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Special Issue "Special Issue of the Manufacturing Engineering Society (MES)"

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Manufacturing Processes and Systems".

Deadline for manuscript submissions: closed (7 July 2018)

Special Issue Editors

Guest Editor
Prof. Eva M. Rubio

Department of Manufacturing Engineering, Universidad Nacional de Educación a Distancia (UNED), Juan del Rosal 12, E28040-Madrid, Spain
Website | E-Mail
Interests: machining; lightweight materials (magnesium alloys, aluminum alloys, titanium alloys); metal forming technology and processing; sustainable manufacturing; industrial metrology; virtual reality; e-learning; innovation in distance teaching
Guest Editor
Prof. Ana M. Camacho

Department of Manufacturing Engineering, Universidad Nacional de Educación a Distancia (UNED), Juan del Rosal 12, E28040-Madrid, Spain
Website | E-Mail
Interests: metal forming of metallic materials (lightweight alloys, advanced high strength steels); additive manufacturing; industrial metrology; materials technology; development of virtual labs

Special Issue Information

Dear Colleagues,

The Special Issue on the Manufacturing Engineering Society is dedicated to publishing high-quality and original research in the field of Manufacturing Engineering and it is promoted by the Manufacturing Engineering Society.

The main objective of this Special Issue is to publish outstanding papers presenting cutting-edge advances in the field of Manufacturing Engineering and materials processing.

The journal aims to explore the evolution of traditional manufacturing models towards the new requirements of the Manufacturing Industry 4.0 and how manufacturing professionals should face the resulting competitive challenges, in the context of an ever-increasing use of digital information systems and communication technologies. Contributions on emerging methods and technologies, such as those related to additive manufacturing will have special relevance within this Special Issue, as well as those ones where sustainability and environmental issues play a fundamental role in manufacturing.

The main topics covered by this Special Issue are scientific contributions on the following manufacturing research topics:

  • Additive manufacturing and 3D printing
  • Advances and innovations in manufacturing processes
  • Sustainable and green manufacturing
  • Micro and nano-manufacturing
  • Manufacturing of new materials
  • Manufacturing systems: machines, equipment and tooling
  • Robotics, mechatronics and manufacturing automation
  • Metrology and quality in manufacturing
  • Industry 4.0
  • Product Lifecycle Management (PLM) technologies
  • Design, modeling and simulation in manufacturing engineering
  • Production planning
  • Manufacturing engineering and Society

The above list is not exhaustive and papers on other topics associated with advances in manufacturing engineering are also welcome.

Excellent papers selected from the Manufacturing Engineering Society International Conference can be also be part of this Special Issue, provided that the degree of novelty of the contribution is guaranteed and the paper has been not published elsewhere.

It is our pleasure to invite professionals from industry, academic institutions and research centers from around the world to submit their contributions to this Special Issue.

text

Prof. Eva M. Rubio
Prof. Ana M. Camacho
Guest Editors

  • Members of the Manufacturing Engineering Society will benefit from a 15% discount (approx. 200 €) on the article processing charges. If you are not a member yet, please find more information on how to join the society (here). Regular individual member fee 75 €/year, student fee 35 €/year.

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Additive manufacturing
  • 3D printing
  • Machining
  • Forming
  • Moulding
  • Non-traditional manufacturing processes
  • Welding
  • Joining
  • Assembly processes
  • Friction
  • Wear
  • Sustainable manufacturing
  • Green manufacturing
  • Micro-manufacturing
  • Nano-manufacturing
  • Manufacturing systems
  • Robotics
  • Mechatronics
  • Manufacturing automation
  • Metrology
  • Quality in manufacturing
  • Industry 4.0
  • Digital manufacturing
  • Smart manufacturing
  • Virtual manufacturing
  • Product Lifecycle Management (PLM)
  • Modeling and simulation
  • Production planning
  • Ergonomy
  • Safety and risks
  • Heritage

Published Papers (48 papers)

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Open AccessArticle Optimization of Hole-Flanging by Single Point Incremental Forming in Two Stages
Materials 2018, 11(10), 2029; https://doi.org/10.3390/ma11102029
Received: 20 September 2018 / Revised: 12 October 2018 / Accepted: 17 October 2018 / Published: 18 October 2018
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Abstract
Single point incremental forming (SPIF) has been demonstrated to accomplish current trends and requirements in industry. Recent studies have applied this technology to hole-flanging by performing different forming strategies using one or multiple stages. In this work, an optimization procedure is proposed to
[...] Read more.
Single point incremental forming (SPIF) has been demonstrated to accomplish current trends and requirements in industry. Recent studies have applied this technology to hole-flanging by performing different forming strategies using one or multiple stages. In this work, an optimization procedure is proposed to balance fabrication time and thickness distribution along the produced flange in a two-stage variant. A detailed analytical, numerical and experimental investigation is carried out to provide, evaluate and corroborate the optimal strategy. The methodology begins by analysing the single-stage process to understand the deformation and failure mechanisms. Accordingly, a parametric two-stage SPIF strategy is proposed and evaluated by an explicit Finite Element Analysis to find the optimal parameters. The study is focused on AA7075-O sheets with different pre-cut hole diameters and considering a variety of forming tool radii. The study exposes the relevant role of the tool radius in finding the optimal hole-flanging process by the proposed two-stage SPIF. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Improving Pallet Mover Safety in the Manufacturing Industry: A Bow-Tie Analysis of Accident Scenarios
Materials 2018, 11(10), 1955; https://doi.org/10.3390/ma11101955
Received: 22 August 2018 / Revised: 9 October 2018 / Accepted: 9 October 2018 / Published: 12 October 2018
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Abstract
A Belgian manufacturing company uses pallet movers for internal transport. Despite the company’s efforts to improve occupational safety, accidents with pallet movers remain noteworthy. In order to control occupational accidents, it is crucial to have a clear view of the potential accident scenarios
[...] Read more.
A Belgian manufacturing company uses pallet movers for internal transport. Despite the company’s efforts to improve occupational safety, accidents with pallet movers remain noteworthy. In order to control occupational accidents, it is crucial to have a clear view of the potential accident scenarios that are present in a company. The bow-tie method is a way to capture and visualize these accident processes in an integrative way. Included in the bow-tie are safety barriers (both technical as organizational and human) and management delivery systems that can intervene in these accident processes. Once bow-ties are composed, they are an excellent point of departure to assign indicators to the safety barriers and management delivery systems in order to control (i.e., prevent or mitigate) accident scenarios. Two types of indicators can be distinguished. Firstly, there are general indicators that are assigned to management delivery systems interrupting multiple accident scenarios, which can yield a higher safety gain (as they intervene in multiple accident scenarios). Secondly, there are scenario-specific indicators targeting one specific accident scenario, which can be valuable as they target a specific problem in the company. For the development of the bow-ties, a multi-method design with the inclusion of different data sources was used, leading to a comprehensive overview. This makes the bow-tie analysis of internal transport with pallet movers transferable to other settings where pallet movers are used for internal transport. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessFeature PaperArticle Risk Management of Hazardous Materials in Manufacturing Processes: Links and Transitional Spaces between Occupational Accidents and Major Accidents
Materials 2018, 11(10), 1915; https://doi.org/10.3390/ma11101915
Received: 12 September 2018 / Revised: 30 September 2018 / Accepted: 5 October 2018 / Published: 9 October 2018
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Abstract
Manufacturing processes involving chemical agents are evolving at great speed. In this context, managing chemical risk is especially important towards preventing both occupational accidents and major accidents. Directive 89/391/EEC and Directive 2012/18/EU, respectively, are enforced in the European Union (EU) to this end.
[...] Read more.
Manufacturing processes involving chemical agents are evolving at great speed. In this context, managing chemical risk is especially important towards preventing both occupational accidents and major accidents. Directive 89/391/EEC and Directive 2012/18/EU, respectively, are enforced in the European Union (EU) to this end. These directives may be further complemented by the recent ISO 45001:2018 standard regarding occupational health and safety management systems. These three management systems are closely related. However, scientific literature tackles the researching of these accidents independently. Thus, the main objective of this work is to identify and analyse the links and transitional spaces between the risk management of both types of accident. Among the results obtained, three transitional spaces can be pointed out which result from the intersection of the three systems mentioned. Similarly, the intersection of these spaces gives shape to a specific transitional space defined by the individual directives linked to Directive 89/391/EEC. These results are limited from a regulatory and technical perspective. Thus, the results are a starting point towards developing models that integrate the management systems studied. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Influence of Milling Parameters on Mechanical Properties of AA7075 Aluminum under Corrosion Conditions
Materials 2018, 11(9), 1751; https://doi.org/10.3390/ma11091751
Received: 1 July 2018 / Revised: 1 September 2018 / Accepted: 14 September 2018 / Published: 17 September 2018
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Abstract
The paper describes an experimental study developed on the AA7075 T651, which is an aluminum alloy extensively used in the aeronautical industry. This work presents a double approach of investigation where there is no literature about previous research. This includes the analysis of
[...] Read more.
The paper describes an experimental study developed on the AA7075 T651, which is an aluminum alloy extensively used in the aeronautical industry. This work presents a double approach of investigation where there is no literature about previous research. This includes the analysis of the results obtained by the combination of mechanical and chemical actions on the mechanical properties of this material. On the one hand, the combinations of relevant milling parameters (feed rate, cutting speed) on flat samples (flat specimens have been selected by attempting to reproduce with the most accurate way the geometry and the type of machining process known as face milling is usually used in this manufacturing field). On the other hand, the stimulating effect of the corrosion by salt spray on selected batches of specimens was machined in the previous stage. Results from tensile tests performed on the whole of specimens allowed us to evaluate how the main mechanical properties (yield strength, tensile strength, and elongation at break) have been affected by the processes applied. Elongation at the break presents a reduction in an inverse order to feed a rate increase (up to 24.5%) and this reduction is extended (additional 19.17%) in specimens under corrosion conditions, which results in a greater fragility of the material. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Contribution to Reduce the Influence of the Free Sliding Edge on Compression-After-Impact Testing of Thin-Walled Undamaged Composites Plates
Materials 2018, 11(9), 1708; https://doi.org/10.3390/ma11091708
Received: 2 July 2018 / Revised: 29 August 2018 / Accepted: 6 September 2018 / Published: 13 September 2018
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Abstract
Standard Compression-After-Impact test devices show a weakening effect on thin-walled specimens due to a free panel edge that is required for compression. As a result, thin-walled undamaged samples do not break in the free measuring area but near the free edge and along
[...] Read more.
Standard Compression-After-Impact test devices show a weakening effect on thin-walled specimens due to a free panel edge that is required for compression. As a result, thin-walled undamaged samples do not break in the free measuring area but near the free edge and along the supports. They also show a strength reduction due to the free edge which can become potentially relevant for very weakly damaged panels. In order to reduce the free edge influence on the measured strength, a modified Compression-After-Impact test device has been developed. In an experimental investigation with carbon fiber reinforced plastics, the modified device is compared with a standard device. It is shown that thin-walled undamaged specimens investigated with the modified device now mainly break within the free measuring area and no longer at the free edge and along the bearings as it is the case for standard test devices. The modified device does not cause a free edge weakening effect in comparison to standard devices. The modified device is therefore more suitable for determining the compression strengths of undamaged thin-walled composite plates. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Methodology to Reduce Distortion Using a Hybrid Thermal Welding Process
Materials 2018, 11(9), 1649; https://doi.org/10.3390/ma11091649
Received: 6 July 2018 / Revised: 1 September 2018 / Accepted: 3 September 2018 / Published: 7 September 2018
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Abstract
Welding is a thermal process which results in high strain and stress values in the material and leads to its change of phase. This might cause significant distortions in the welded structure, which often becomes a relevant design and manufacturing issue. This study
[...] Read more.
Welding is a thermal process which results in high strain and stress values in the material and leads to its change of phase. This might cause significant distortions in the welded structure, which often becomes a relevant design and manufacturing issue. This study deals with a line-heating-based forming process that is applied at the moment of the welding operation, with the final objective of minimizing distortion. A FEM (finite element method) based on a thermo-elastoplastic approach is used here. The computational method is first calibrated in three stages: heatline forming calibration, flame heat source calibration, and the weld process. The final model presented in this work simulates a hybrid process called htTTT (high-temperature thermal transient tensioning) which was optimized over large T welds to minimize the final distortion of the components. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Force Prediction for Incremental Forming of Polymer Sheets
Materials 2018, 11(9), 1597; https://doi.org/10.3390/ma11091597
Received: 29 June 2018 / Revised: 24 August 2018 / Accepted: 30 August 2018 / Published: 3 September 2018
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Abstract
Incremental sheet forming (ISF) is gaining attention as a low cost prototyping and small batch production solution to obtain 3D components. In ISF, the forming force is key to define an adequate setup, avoiding damage and reducing wear, as well as to determine
[...] Read more.
Incremental sheet forming (ISF) is gaining attention as a low cost prototyping and small batch production solution to obtain 3D components. In ISF, the forming force is key to define an adequate setup, avoiding damage and reducing wear, as well as to determine the energy consumption and the final shape of the part. Although there are several analytical, experimental and numerical approaches to estimate the axial forming force for metal sheets, further efforts must be done to extend the study to polymers. This work presents two procedures for predicting axial force in Single Point Incremental Forming (SPIF) of polymer sheets. Particularly, a numerical model based on the Finite Element Model (FEM), which considers a hyperelastic-plastic constitutive equation, and a simple semi-analytical model that extends the known specific energy concept used in machining. A set of experimental tests was used to validate the numerical model, and to determine the specific energy for two polymer sheets of polycarbonate (PC) and polyvinyl chloride (PVC). The approaches provide results in good agreement with additional real examples. Moreover, the numerical model is useful for accurately predicting temperature and thickness. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Joint Optimization of Process Flow and Scheduling in Service-Oriented Manufacturing Systems
Materials 2018, 11(9), 1559; https://doi.org/10.3390/ma11091559
Received: 25 June 2018 / Accepted: 24 August 2018 / Published: 29 August 2018
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Abstract
Customer-oriented management of manufacturing systems is crucial in service-oriented production and product service systems. This paper develops the selection of dispatching rules in combination with alternative process flow designs and demand mix, for a maintenance, repair and overhaul center (MRO) of turbo shaft
[...] Read more.
Customer-oriented management of manufacturing systems is crucial in service-oriented production and product service systems. This paper develops the selection of dispatching rules in combination with alternative process flow designs and demand mix, for a maintenance, repair and overhaul center (MRO) of turbo shaft engines, both for complete engines and engine modules. After an initial systematic screening of priority dispatching rules, the design of experiments and discrete-event simulation allows a quantitative analysis of the better rules for the alternative process flows with internal and service metrics. Next, the design of experiments with analysis of variance and the Taguchi approach enables a search for the optimal combination of process flow and dispatching rules. The consideration of extra costs for overdue work orders into the costing breakdown provides a quantitative evaluation of the optimum range of load for the facility. This facilitates the discussion of the significant trade-offs of cost, service, and flexibility in the production system and the operational management alternatives for decision-making. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle 3D Printing of Porous Scaffolds with Controlled Porosity and Pore Size Values
Materials 2018, 11(9), 1532; https://doi.org/10.3390/ma11091532
Received: 27 June 2018 / Revised: 21 August 2018 / Accepted: 22 August 2018 / Published: 25 August 2018
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Abstract
3D printed scaffolds can be used, for example, in medical applications for simulating body tissues or for manufacturing prostheses. However, it is difficult to print porous structures of specific porosity and pore size values with fused deposition modelling (FDM) technology. The present paper
[...] Read more.
3D printed scaffolds can be used, for example, in medical applications for simulating body tissues or for manufacturing prostheses. However, it is difficult to print porous structures of specific porosity and pore size values with fused deposition modelling (FDM) technology. The present paper provides a methodology to design porous structures to be printed. First, a model is defined with some theoretical parallel planes, which are bounded within a geometrical figure, for example a disk. Each plane has randomly distributed points on it. Then, the points are joined with lines. Finally, the lines are given a certain volume and the structure is obtained. The porosity of the structure depends on three geometrical variables: the distance between parallel layers, the number of columns on each layer and the radius of the columns. In order to obtain mathematical models to relate the variables with three responses, the porosity, the mean of pore diameter and the variance of pore diameter of the structures, design of experiments with three-level factorial analysis was used. Finally, multiobjective optimization was carried out by means of the desirability function method. In order to favour fixation of the structures by osseointegration, porosity range between 0.5 and 0.75, mean of pore size between 0.1 and 0.3 mm, and variance of pore size between 0.000 and 0.010 mm2 were selected. Results showed that the optimal solution consists of a structure with a height between layers of 0.72 mm, 3.65 points per mm2 and a radius of 0.15 mm. It was observed that, given fixed height and radius values, the three responses decrease with the number of points per surface unit. The increase of the radius of the columns implies the decrease of the porosity and of the mean of pore size. The decrease of the height between layers leads to a sharper decrease of both the porosity and the mean of pore size. In order to compare calculated and experimental values, scaffolds were printed in polylactic acid (PLA) with FDM technology. Porosity and pore size were measured with X-ray tomography. Average value of measured porosity was 0.594, while calculated porosity was 0.537. Average value of measured mean of pore size was 0.372 mm, while calculated value was 0.434 mm. Average value of variance of pore size was 0.048 mm2, higher than the calculated one of 0.008 mm2. In addition, both round and elongated pores were observed in the printed structures. The current methodology allows designing structures with different requirements for porosity and pore size. In addition, it can be applied to other responses. It will be very useful in medical applications such as the simulation of body tissues or the manufacture of prostheses. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle A Tangible Educative 3D Printed Atlas of the Rat Brain
Materials 2018, 11(9), 1531; https://doi.org/10.3390/ma11091531
Received: 29 June 2018 / Revised: 22 August 2018 / Accepted: 23 August 2018 / Published: 25 August 2018
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Abstract
In biology and neuroscience courses, brain anatomy is usually explained using Magnetic Resonance (MR) images or histological sections of different orientations. These can show the most important macroscopic areas in an animals’ brain. However, this method is neither dynamic nor intuitive. In this
[...] Read more.
In biology and neuroscience courses, brain anatomy is usually explained using Magnetic Resonance (MR) images or histological sections of different orientations. These can show the most important macroscopic areas in an animals’ brain. However, this method is neither dynamic nor intuitive. In this work, an anatomical 3D printed rat brain with educative purposes is presented. Hand manipulation of the structure, facilitated by the scale up of its dimensions, and the ability to dismantle the “brain” into some of its constituent parts, facilitates the understanding of the 3D organization of the nervous system. This is an alternative method for teaching students in general and biologists in particular the rat brain anatomy. The 3D printed rat brain has been developed with eight parts, which correspond to the most important divisions of the brain. Each part has been fitted with interconnections, facilitating assembling and disassembling as required. These solid parts were smoothed out, modified and manufactured through 3D printing techniques with poly(lactic acid) (PLA). This work presents a methodology that could be expanded to almost any field of clinical and pre-clinical research, and moreover it avoids the need for dissecting animals to teach brain anatomy. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Simulation of Laser Heating of Aluminum and Model Validation via Two-Color Pyrometer and Shape Assessment
Materials 2018, 11(9), 1506; https://doi.org/10.3390/ma11091506
Received: 4 July 2018 / Revised: 14 August 2018 / Accepted: 20 August 2018 / Published: 22 August 2018
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Abstract
The modeling of laser-based processes is increasingly addressed in a competitive environment for two main reasons: Preventing a trial-and-error approach to set the optimum processing conditions and non-destructive real-time control. In this frame, a thermal model for laser heating in the form of
[...] Read more.
The modeling of laser-based processes is increasingly addressed in a competitive environment for two main reasons: Preventing a trial-and-error approach to set the optimum processing conditions and non-destructive real-time control. In this frame, a thermal model for laser heating in the form of non-penetrative bead-on-plate welds of aluminum alloy 2024 is proposed in this paper. A super-Gaussian profile is considered for the transverse optical intensity and a number of laws for temperature-dependent material properties have been included aiming to improve the reliability of the model. The output of the simulation in terms of both thermal evolution of the parent metal and geometry of the fusion zone is validated in comparison with the actual response: namely, a two-color pyrometer is used to infer the thermal history on the exposed surface around the scanning path, whereas the shape and size of the fusion zone are assessed in the transverse cross-section. With an average error of 3% and 4%, the model is capable of predicting the peak temperature and the depth of the fusion zone upon laser heating, respectively. The model is intended to offer a comprehensive description of phenomena in laser heating in preparation for a further model for repairing via additive manufacturing. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Feature-Based Framework for Inspection Process Planning
Materials 2018, 11(9), 1504; https://doi.org/10.3390/ma11091504
Received: 30 June 2018 / Revised: 17 August 2018 / Accepted: 19 August 2018 / Published: 22 August 2018
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Abstract
Feature-based approaches have been profusely used in the last decades to incorporate domain-specific knowledge in the design and development of technical systems that, according to the new Concurrent Engineering approaches, involves not only the definition of the product, but also of the required
[...] Read more.
Feature-based approaches have been profusely used in the last decades to incorporate domain-specific knowledge in the design and development of technical systems that, according to the new Concurrent Engineering approaches, involves not only the definition of the product, but also of the required manufacturing/inspection/assembly process and the corresponding production system. Although the ability of feature-based modeling to ease and integrate knowledge intensive processes has always been recognised, in practise the different feature-based modeling proposals are strongly dependent on the domain and on the development stage of the solution (conceptual, detailed, etc.). On the other hand, inspection process planning, including the design and selection of the technical system to realize the dimensional and geometrical verification of the manufactured artefacts, has been traditionally considered separately from the rest of the manufacturing process planning, and even also from the product functional specification tasks. In this work, a feature-based framework for inspection process planning, based on a similar approach to the one applied in GD&T (Geometrical Dimensioning & Tolerancing) specification, analysis and validation of product artefacts, is presented. With this work, the proposed framework and feature concept ability to model interaction components belonging to both the product and the inspection system (inspection solution) is proved. Moreover, to facilitate the Collaborative and Integrated Development of Product-Process-Resource, the Inspection Feature has been conceived as a specialization of a generic Feature previously proposed by the authors. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Delphi Prospection on Additive Manufacturing in 2030: Implications for Education and Employment in Spain
Materials 2018, 11(9), 1500; https://doi.org/10.3390/ma11091500
Received: 7 July 2018 / Revised: 9 August 2018 / Accepted: 14 August 2018 / Published: 22 August 2018
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Abstract
The term additive manufacturing (AM) groups together a set of technologies with similar characteristics forming part of the Fourth Industrial Revolution. AM is being developed globally, as evidenced by the standards published by and the agreements between the ISO and the ASTM in
[...] Read more.
The term additive manufacturing (AM) groups together a set of technologies with similar characteristics forming part of the Fourth Industrial Revolution. AM is being developed globally, as evidenced by the standards published by and the agreements between the ISO and the ASTM in 2013. The purpose of this paper is to anticipate the main changes that will occur in AM by 2030 as forecast by more than 100 Spanish experts through Delphi prospection performed in 2018. In this way, the areas, aspects, and business models with the greatest probabilities of occurrence are obtained. The need for technical experts with specific knowledge and skills requires changes to current training syllabuses. Such changes will enable students to have the profiles foreseen in these job trends. The encouragement of STEAM (Science, Technology, Engineering, Arts, and Mathematics) training through the introduction of AM in study plans may be an appropriate alternative. Finally, the consequences of the Fourth Industrial Revolution for the employment market and on jobs, particularly in Spain, are set out and the latest Spanish Research, Development, and Innovation (R&D + I) plans are summarized as the framework for the possible implementation and development of AM. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Some Considerations about the Use of Contact and Confocal Microscopy Methods in Surface Texture Measurement
Materials 2018, 11(8), 1484; https://doi.org/10.3390/ma11081484
Received: 1 July 2018 / Revised: 17 August 2018 / Accepted: 18 August 2018 / Published: 20 August 2018
PDF Full-text (3828 KB) | HTML Full-text | XML Full-text
Abstract
Surface metrology employs various measurement techniques, among which there has been an increase of noteworthy research into non-contact optical and contact stylus methods. However, some deeper considerations about their differentiation and compatibility are still lacking and necessary. This work compares the measurement characteristics
[...] Read more.
Surface metrology employs various measurement techniques, among which there has been an increase of noteworthy research into non-contact optical and contact stylus methods. However, some deeper considerations about their differentiation and compatibility are still lacking and necessary. This work compares the measurement characteristics of the confocal microscope with the portable stylus profilometer instrumentation, from a metrological point of view (measurement precision and accuracy, and complexity of algorithms for data processing) and an operational view (measuring ranges, measurement speed, environmental and operational requirements, and cost). Mathematical models and algorithms for roughness parameters calculation and their associated uncertainties evaluation are developed and validated. The experimental results demonstrate that the stylus profilometer presents the most reliable measurement with the highest measurement speed and the least complex algorithms, while the image confocal method takes advantage of higher vertical and horizontal resolution when compared with the employed stylus profilometer. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Characterization of a New Dry Drill-Milling Process of Carbon Fibre Reinforced Polymer Laminates
Materials 2018, 11(8), 1470; https://doi.org/10.3390/ma11081470
Received: 2 July 2018 / Revised: 7 August 2018 / Accepted: 13 August 2018 / Published: 18 August 2018
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Abstract
Carbon Fibre Reinforced Polymer (CFRP) composites are widely used in aerospace applications that require severe quality parameters. To simplify the assembly operations and reduce the associated costs, the current trend in industry is to optimize the drilling processes. However, the machining of CFRP
[...] Read more.
Carbon Fibre Reinforced Polymer (CFRP) composites are widely used in aerospace applications that require severe quality parameters. To simplify the assembly operations and reduce the associated costs, the current trend in industry is to optimize the drilling processes. However, the machining of CFRP composites is very challenging compared with metals, and several defect types can be generated by drilling. The emerging process of orbital drilling can greatly reduce the defects associated with the traditional drilling of CFRP, but it is a more complex process requiring careful process parameters selection and it does not allow for the complete elimination of the thrust force responsible for delamination damage. As an alternative to traditional and orbital drilling, this work presents a new hole making process, where the hole is realized by a combination of drilling and peripheral milling performed using the same cutting tool following a novel tool path strategy. An original tool design principle is proposed to realize a new drill-milling tool, made of a first drilling and a subsequent milling portion. Two different tool configurations are experimentally tested to evaluate the performance of the newly-conceived combined drill-milling process. This process is quick and easy, and the experimental results show an improvement in the drilled hole quality. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Product Lifecycle Management as Data Repository for Manufacturing Problem Solving
Materials 2018, 11(8), 1469; https://doi.org/10.3390/ma11081469
Received: 2 July 2018 / Revised: 9 August 2018 / Accepted: 14 August 2018 / Published: 18 August 2018
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Abstract
Fault diagnosis presents a considerable difficulty to human operators in supervisory control of manufacturing systems. Implementing Internet of Things (IoT) technologies in existing manufacturing facilities implies an investment, since it requires upgrading them with sensors, connectivity capabilities, and IoT software platforms. Aligned with
[...] Read more.
Fault diagnosis presents a considerable difficulty to human operators in supervisory control of manufacturing systems. Implementing Internet of Things (IoT) technologies in existing manufacturing facilities implies an investment, since it requires upgrading them with sensors, connectivity capabilities, and IoT software platforms. Aligned with the technological vision of Industry 4.0 and based on currently existing information databases in the industry, this work proposes a lower-investment alternative solution for fault diagnosis and problem solving. This paper presents the details of the information and communication models of an application prototype oriented to production. It aims at assisting shop-floor actors during a Manufacturing Problem Solving (MPS) process. It captures and shares knowledge, taking existing Process Failure Mode and Effect Analysis (PFMEA) documents as an initial source of information related to potential manufacturing problems. It uses a Product Lifecycle Management (PLM) system as source of manufacturing context information related to the problems under investigation and integrates Case-Based Reasoning (CBR) technology to provide information about similar manufacturing problems. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Experimental Study of Macro and Microgeometric Defects in Drilled Carbon Fiber Reinforced Plastics by Laser Beam Machining
Materials 2018, 11(8), 1466; https://doi.org/10.3390/ma11081466
Received: 1 July 2018 / Revised: 13 August 2018 / Accepted: 13 August 2018 / Published: 18 August 2018
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Abstract
Plastic matrix composite materials are an excellent choice for structural applications where high strength-weight and stiffness-weight ratios are required. These materials are being increasingly used in diverse industrial sectors, particularly in aerospace. Due to the strict tolerances required, they are usually machined with
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Plastic matrix composite materials are an excellent choice for structural applications where high strength-weight and stiffness-weight ratios are required. These materials are being increasingly used in diverse industrial sectors, particularly in aerospace. Due to the strict tolerances required, they are usually machined with drilling cycles due to the type of mounting through rivets. In this sense, laser beam drilling is presented as an alternative to conventional drilling due to the absence of tool wear, cutting forces, or vibrations during the cutting process. However, the process carries with it other problems that compromise the integrity of the material. One of these is caused by the high temperatures generated during the interaction between the laser and the material. In this work, variance analysis is used to study the influence of scanning speed and frequency on macro geometric parameters, surface quality, and defects (taper and heat affected zone). Also, in order to identify problems in the wall of the drill, stereoscopic optical microscopy (SOM) and scanning electron microscopy (SEM) techniques are used. This experimental procedure reveals the conditions that minimize deviations, defects, and damage in machining holes. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Analysis of Surface Extraction Methods Based on Gradient Operators for Computed Tomography in Metrology Applications
Materials 2018, 11(8), 1461; https://doi.org/10.3390/ma11081461
Received: 6 July 2018 / Revised: 13 August 2018 / Accepted: 14 August 2018 / Published: 17 August 2018
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Abstract
Among the multiple factors influencing the accuracy of Computed Tomography measurements, the surface extraction process is a significant contributor. The location of the surface for metrological applications is generally based on the definition of a gray value as a characteristic of similarity to
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Among the multiple factors influencing the accuracy of Computed Tomography measurements, the surface extraction process is a significant contributor. The location of the surface for metrological applications is generally based on the definition of a gray value as a characteristic of similarity to define the regions of interest. A different approach is to perform the detection or location of the surface based on the discontinuity or gradient. In this paper, an adapted 3D Deriche algorithm based on gradient information is presented and compared with a previously developed adapted Canny algorithm for different surface types. Both algorithms have been applied to nine calibrated workpieces with different geometries and materials. Both the systematic error and measurement uncertainty have been determined. The results show a significant reduction of the deviations obtained with the Deriche-based algorithm in the dimensions defined by flat surfaces. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Fabrication of Polymer Microstructures of Various Angles via Synchrotron X-Ray Lithography Using Simple Dimensional Transformation
Materials 2018, 11(8), 1460; https://doi.org/10.3390/ma11081460
Received: 7 July 2018 / Revised: 6 August 2018 / Accepted: 15 August 2018 / Published: 17 August 2018
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Abstract
In this paper, we developed a method of fabricating polymer microstructures at various angles on a single substrate via synchrotron X-ray lithography coupled with simple dimensional transformations. Earlier efforts to create various three-dimensional (3D) features on flat substrates focused on the exposure technology,
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In this paper, we developed a method of fabricating polymer microstructures at various angles on a single substrate via synchrotron X-ray lithography coupled with simple dimensional transformations. Earlier efforts to create various three-dimensional (3D) features on flat substrates focused on the exposure technology, material properties, and light sources. A few research groups have sought to create microstructures on curved substrates. We created tilted microstructures of various angles by simply deforming the substrate from 3D to two-dimensional (2D). The microstructural inclination angles changed depending on the angles of the support at particular positions. We used convex, concave, and S-shaped supports to fabricate microstructures with high aspect ratios (1:11) and high inclination angles (to 79°). The method is simple and can be extended to various 3D microstructural applications; for example, the fabrication of microarrays for optical components, and tilted micro/nanochannels for biological applications. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Analysis of Favorable Process Conditions for the Manufacturing of Thin-Wall Pieces of Mild Steel Obtained by Wire and Arc Additive Manufacturing (WAAM)
Materials 2018, 11(8), 1449; https://doi.org/10.3390/ma11081449
Received: 7 July 2018 / Revised: 3 August 2018 / Accepted: 13 August 2018 / Published: 16 August 2018
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Abstract
One of the challenges in additive manufacturing (AM) of metallic materials is to obtain workpieces free of defects with excellent physical, mechanical, and metallurgical properties. In wire and arc additive manufacturing (WAAM) the influences of process conditions on thermal history, microstructure and resultant
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One of the challenges in additive manufacturing (AM) of metallic materials is to obtain workpieces free of defects with excellent physical, mechanical, and metallurgical properties. In wire and arc additive manufacturing (WAAM) the influences of process conditions on thermal history, microstructure and resultant mechanical and surface properties of parts must be analyzed. In this work, 3D metallic parts of mild steel wire (American Welding Society-AWS ER70S-6) are built with a WAAM process by depositing layers of material on a substrate of a S235 JR steel sheet of 3 mm thickness under different process conditions, using as welding process the gas metal arc welding (GMAW) with cold metal transfer (CMT) technology, combined with a positioning system such as a computer numerical controlled (CNC) milling machine. Considering the hardness profiles, the estimated ultimate tensile strengths (UTS) derived from the hardness measurements and the microstructure findings, it can be concluded that the most favorable process conditions are the ones provided by CMT, with homogeneous hardness profiles, good mechanical strengths in accordance to conditions defined by standard, and without formation of a decohesionated external layer; CMT Continuous is the optimal option as the mechanical properties are better than single CMT. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Analysis of Force Signals for the Estimation of Surface Roughness during Robot-Assisted Polishing
Materials 2018, 11(8), 1438; https://doi.org/10.3390/ma11081438
Received: 11 July 2018 / Revised: 9 August 2018 / Accepted: 13 August 2018 / Published: 15 August 2018
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Abstract
In this study feature extraction of force signals detected during robot-assisted polishing processes was carried out to estimate the surface roughness during the process. The purpose was to collect significant features from the signal that allow the determination of the end point of
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In this study feature extraction of force signals detected during robot-assisted polishing processes was carried out to estimate the surface roughness during the process. The purpose was to collect significant features from the signal that allow the determination of the end point of the polishing process based on surface roughness. For this objective, dry polishing turning tests were performed on a Robot-Assisted Polishing (RAP) machine (STRECON NanoRAP 200) during three polishing sessions, using the same polishing conditions. Along the tests, force signals were acquired and offline surface roughness measurements were taken at the end of each polishing session. As a main conclusion, it can be affirmed, regarding the force signal, that features extracted from both time and frequency domains are valuable data for the estimation of surface roughness. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Assessment of the Potential Economic Impact of the Use of AM Technologies in the Cost Levels of Manufacturing and Stocking of Spare Part Products
Materials 2018, 11(8), 1429; https://doi.org/10.3390/ma11081429
Received: 30 June 2018 / Revised: 9 August 2018 / Accepted: 9 August 2018 / Published: 14 August 2018
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Abstract
Additive manufacturing (AM) technologies are appropriate manufacturing technologies to produce low rotation products of high added value. Products in the spare parts business usually have discontinuous demand levels of reduced numbers of parts. Indeed, spare parts inventories handle myriad of products that require
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Additive manufacturing (AM) technologies are appropriate manufacturing technologies to produce low rotation products of high added value. Products in the spare parts business usually have discontinuous demand levels of reduced numbers of parts. Indeed, spare parts inventories handle myriad of products that require big immobilized investments while having an intrinsic risk of no-use (for example due to obsolescence or spoilage). Based on these issues, the present work analyses the fundamental cost factors in a real case study of a company dedicated to the supply of spare parts for fluid conduction systems. Real inventory data is assessed to determine the product taxonomy and its associated costs. A representative product of the stock is analyzed in detail on original manufacturing costs, in AM costs and then redesigned with topological optimization to reduce the AM cost levels (via design for additive manufacturing). A general equation for cost assessment is formulated. Given the specific data collected from the company, the parameters in this general equation are calculated. Finally, the general equation and the product cost reduction achieved are used to explore the potential economic impact of the use of AM technologies in the cost levels of manufacturing and stocking of spare part products. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Design of a Scaffold Parameter Selection System with Additive Manufacturing for a Biomedical Cell Culture
Materials 2018, 11(8), 1427; https://doi.org/10.3390/ma11081427
Received: 10 July 2018 / Revised: 8 August 2018 / Accepted: 10 August 2018 / Published: 14 August 2018
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Abstract
Open-source 3D printers mean objects can be quickly and efficiently produced. However, design and fabrication parameters need to be optimized to set up the correct printing procedure; a procedure in which the characteristics of the printing materials selected for use can also influence
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Open-source 3D printers mean objects can be quickly and efficiently produced. However, design and fabrication parameters need to be optimized to set up the correct printing procedure; a procedure in which the characteristics of the printing materials selected for use can also influence the process. This work focuses on optimizing the printing process of the open-source 3D extruder machine RepRap, which is used to manufacture poly(ε-caprolactone) (PCL) scaffolds for cell culture applications. PCL is a biocompatible polymer that is free of toxic dye and has been used to fabricate scaffolds, i.e., solid structures suitable for 3D cancer cell cultures. Scaffold cell culture has been described as enhancing cancer stem cell (CSC) populations related to tumor chemoresistance and/or their recurrence after chemotherapy. A RepRap BCN3D+ printer and 3 mm PCL wire were used to fabricate circular scaffolds. Design and fabrication parameters were first determined with SolidWorks and Slic3r software and subsequently optimized following a novel sequential flowchart. In the flowchart described here, the parameters were gradually optimized step by step, by taking several measurable variables of the resulting scaffolds into consideration to guarantee high-quality printing. Three deposition angles (45°, 60° and 90°) were fabricated and tested. MCF-7 breast carcinoma cells and NIH/3T3 murine fibroblasts were used to assess scaffold adequacy for 3D cell cultures. The 60° scaffolds were found to be suitable for the purpose. Therefore, PCL scaffolds fabricated via the flowchart optimization with a RepRap 3D printer could be used for 3D cell cultures and may boost CSCs to study new therapeutic treatments for this malignant population. Moreover, the flowchart defined here could represent a standard procedure for non-engineers (i.e., mainly physicians) when manufacturing new culture systems is required. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Delamination Study in Edge Trimming of Basalt Fiber Reinforced Plastics (BFRP)
Materials 2018, 11(8), 1418; https://doi.org/10.3390/ma11081418
Received: 29 June 2018 / Revised: 26 July 2018 / Accepted: 27 July 2018 / Published: 13 August 2018
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Abstract
Although there are many machining studies of carbon and glass fiber reinforced plastics, delamination and tool wear of basalt fiber reinforced plastics (BFRP) in edge trimming has not yet studied. This paper presents an end milling study of BFRP fabricated by resin transfer
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Although there are many machining studies of carbon and glass fiber reinforced plastics, delamination and tool wear of basalt fiber reinforced plastics (BFRP) in edge trimming has not yet studied. This paper presents an end milling study of BFRP fabricated by resin transfer molding (RTM), to evaluate delamination types at the top layer of the machined edge with different cutting conditions (cutting speed, feed rate and depth of cut) and fiber volume fraction (40% and 60%). This work quantifies delamination types, using a parameter Sd/L, that evaluates the delamination area (Sd) and the length (L), taking into account tool position in the yarn and movement of yarns during RTM process, which show the random nature of delamination. Delamination was present in all materials with 60% of fiber volume. High values of tool wear did not permit to machine the material due to an excessive delamination. Type II delamination was the most usual delamination type and depth of cut has influence on this type of delamination. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Numerical-Experimental Study of the Consolidation Phenomenon in the Selective Laser Melting Process with a Thermo-Fluidic Coupled Model
Materials 2018, 11(8), 1414; https://doi.org/10.3390/ma11081414
Received: 4 July 2018 / Revised: 7 August 2018 / Accepted: 9 August 2018 / Published: 12 August 2018
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Abstract
One of the main limiting factors for a widespread industrial use of the Selective Laser Melting Process it its lack of productivity, which restricts the use of this technology just for high added-value components. Typically, the thickness of the metallic powder that is
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One of the main limiting factors for a widespread industrial use of the Selective Laser Melting Process it its lack of productivity, which restricts the use of this technology just for high added-value components. Typically, the thickness of the metallic powder that is used lies on the scale of micrometers. The use of a layer up to one millimeter would be necessarily associated to a dramatic increase of productivity. Nevertheless, when the layer thickness increases, the complexity of consolidation phenomena makes the process difficult to be governed. The present work proposes a 3D finite element thermo-coupled model to study the evolution from the metallic powder to the final consolidated material, analyzing specifically the movements and loads of the melt pool, and defining the behavior of some critical thermophysical properties as a function of temperature and the phase of the material. This model uses advanced numerical tools such as the Arbitrary Lagrangean–Eulerian formulation and the Automatic Remeshing technique. A series of experiments have been carried out, using a high thickness powder layer, allowing for a deeper understanding of the consolidation phenomena and providing a reference to compare the results of the numerical calculations. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Accurate Calibration in Multi-Material 3D Bioprinting for Tissue Engineering
Materials 2018, 11(8), 1402; https://doi.org/10.3390/ma11081402
Received: 9 July 2018 / Revised: 1 August 2018 / Accepted: 7 August 2018 / Published: 10 August 2018
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Abstract
Most of the studies in three-dimensional (3D) bioprinting have been traditionally based on printing a single bioink. Addressing the complexity of organ and tissue engineering, however, will require combining multiple building and sacrificial biomaterials and several cells types in a single biofabrication session.
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Most of the studies in three-dimensional (3D) bioprinting have been traditionally based on printing a single bioink. Addressing the complexity of organ and tissue engineering, however, will require combining multiple building and sacrificial biomaterials and several cells types in a single biofabrication session. This is a significant challenge, and, to tackle that, we must focus on the complex relationships between the printing parameters and the print resolution. In this paper, we study the influence of the main parameters driven multi-material 3D bioprinting and we present a method to calibrate these systems and control the print resolution accurately. Firstly, poloxamer hydrogels were extruded using a desktop 3D printer modified to incorporate four microextrusion-based bioprinting (MEBB) printheads. The printed hydrogels provided us the particular range of printing parameters (mainly printing pressure, deposition speed, and nozzle z-offset) to assure the correct calibration of the multi-material 3D bioprinter. Using the printheads, we demonstrated the excellent performance of the calibrated system extruding different fluorescent bioinks. Representative multi-material structures were printed in both poloxamer and cell-laden gelatin-alginate bioinks in a single session corroborating the capabilities of our system and the calibration method. Cell viability was not significantly affected by any of the changes proposed. We conclude that our proposal has enormous potential to help with advancing in the creation of complex 3D constructs and vascular networks for tissue engineering. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Study of the Influence of Shielding Gases on Laser Metal Deposition of Inconel 718 Superalloy
Materials 2018, 11(8), 1388; https://doi.org/10.3390/ma11081388
Received: 28 June 2018 / Revised: 4 August 2018 / Accepted: 6 August 2018 / Published: 9 August 2018
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Abstract
The use of the Laser Metal Deposition (LMD) technology as a manufacturing and repairing technique in industrial sectors like the die and mold and aerospace is increasing within the last decades. Research carried out in the field of LMD process situates argon as
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The use of the Laser Metal Deposition (LMD) technology as a manufacturing and repairing technique in industrial sectors like the die and mold and aerospace is increasing within the last decades. Research carried out in the field of LMD process situates argon as the most usual inert gas, followed by nitrogen. Some leading companies have started to use helium and argon as carrier and shielding gas, respectively. There is therefore a pressing need to know how the use of different gases may affect the LMD process due there being a lack of knowledge with regard to gas mixtures. The aim of the present work is to evaluate the influence of a mixture of argon and helium on the LMD process by analyzing single tracks of deposited material. For this purpose, special attention is paid to the melt pool temperature, as well as to the characterization of the deposited clads. The increment of helium concentration in the gases of the LMD processes based on argon will have three effects. The first one is a slight reduction of the height of the clads. Second, an increase of the temperature of the melt pool. Last, smaller wet angles are obtained for higher helium concentrations. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Surface Quality Enhancement of Fused Deposition Modeling (FDM) Printed Samples Based on the Selection of Critical Printing Parameters
Materials 2018, 11(8), 1382; https://doi.org/10.3390/ma11081382
Received: 29 June 2018 / Revised: 2 August 2018 / Accepted: 6 August 2018 / Published: 8 August 2018
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Abstract
The present paper shows an experimental study on additive manufacturing for obtaining samples of polylactic acid (PLA). The process used for manufacturing these samples was fused deposition modeling (FDM). Little attention to the surface quality obtained in additive manufacturing processes has been paid
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The present paper shows an experimental study on additive manufacturing for obtaining samples of polylactic acid (PLA). The process used for manufacturing these samples was fused deposition modeling (FDM). Little attention to the surface quality obtained in additive manufacturing processes has been paid by the research community. So, this paper aims at filling this gap. The goal of the study is the recognition of critical factors in FDM processes for reducing surface roughness. Two different types of experiments were carried out to analyze five printing parameters. The results were analyzed by means of Analysis of Variance, graphical methods, and non-parametric tests using Spearman’s ρ and Kendall’s τ correlation coefficients. The results showed how layer height and wall thickness are the most important factors for controlling surface roughness, while printing path, printing speed, and temperature showed no clear influence on surface roughness. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Process Parameter Effects on Biocompatible Thermoplastic Sheets Produced by Incremental Forming
Materials 2018, 11(8), 1377; https://doi.org/10.3390/ma11081377
Received: 6 July 2018 / Revised: 3 August 2018 / Accepted: 6 August 2018 / Published: 8 August 2018
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Abstract
There has been increasing interest in the processes that enable part customization and small-batch production in recent years. The prosthetic sector, in which biocompatible materials are used, is one of the areas that requires these types of processes; Incremental Sheet Forming (ISF) technology
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There has been increasing interest in the processes that enable part customization and small-batch production in recent years. The prosthetic sector, in which biocompatible materials are used, is one of the areas that requires these types of processes; Incremental Sheet Forming (ISF) technology can meet these requirements. However, the biocompatible thermoplastic polymers formed by this technology have not yet been tested. Hence, the aim of this paper is to cover this gap in our knowledge by analyzing the effects of process parameters on the ISF process with the aim of optimizing these parameters before the actual production of, in this case, customized prostheses. Tests with polycaprolactone (PCL) and ultra-high molecular weight polyethylene (UHMWPE) were performed. Maximum force, surface roughness and maximum depth were statistically analyzed by means of response surface methodology and survival analysis. Spindle speed and tool diameter were shown to be the most influential process parameters in terms of maximum forming force and surface roughness for both materials. In contrast, survival analysis applied to maximum depth showed a greater influence of tool diameter in PCL sheets and a greater influence of spindle speed in the case of UHMWPE. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle In-Process Measurement for the Process Control of the Real-Time Manufacturing of Tapered Roller Bearings
Materials 2018, 11(8), 1371; https://doi.org/10.3390/ma11081371
Received: 19 June 2018 / Revised: 27 July 2018 / Accepted: 2 August 2018 / Published: 7 August 2018
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Abstract
Tapered roller bearings can accommodate high radial loads as well as high axial loads. The manufacturing process consists of machining processes for ring and component assembly. In this contribution, the parameters of influence on the measurement procedure were studied. These parameters of influence
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Tapered roller bearings can accommodate high radial loads as well as high axial loads. The manufacturing process consists of machining processes for ring and component assembly. In this contribution, the parameters of influence on the measurement procedure were studied. These parameters of influence were classified as environmental, process, and machine parameters. The main objective of this work was to optimize the process using real-time measurements, which required the study of the influence of several parameters on the measurement uncertainty and how to correct their effects. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Cutting Parameter Selection for Efficient and Sustainable Repair of Holes Made in Hybrid Mg–Ti–Mg Component Stacks by Dry Drilling Operations
Materials 2018, 11(8), 1369; https://doi.org/10.3390/ma11081369
Received: 7 July 2018 / Revised: 27 July 2018 / Accepted: 3 August 2018 / Published: 7 August 2018
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Abstract
Drilling is one of the most common machining operations in the aeronautic and aerospace industries. For assembling parts, a large number of holes are usually drilled into the parts so that they can be joined later by rivets. As these holes are subjected
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Drilling is one of the most common machining operations in the aeronautic and aerospace industries. For assembling parts, a large number of holes are usually drilled into the parts so that they can be joined later by rivets. As these holes are subjected to fatigue cycles, they have to be checked regularly for maintenance or repair, since small cracks or damage in its contour can quickly cause breakage of the part, which can have dangerous consequences. This paper focuses on finding the best combinations of cutting parameters to perform repair and maintenance operations of holes in stacked hybrid magnesium–titanium–magnesium components in an efficient, timely, and sustainable (without lubricants or coolants) manner, under dry drilling conditions. For the machining trials, experiments were designed and completed. A product of a full factorial 23 and a block of two factors (3 × 2) was used with surface roughness as the response variable measured as the mean roughness average. Analysis of variance (ANOVA) was used to examine the results. A set of optimized tool and cutting conditions is presented for performing dry drilling repair operations. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Design and Simulation of Production and Maintenance Management Applying the Viable System Model: The Case of an OEM Plant
Materials 2018, 11(8), 1346; https://doi.org/10.3390/ma11081346
Received: 2 July 2018 / Revised: 29 July 2018 / Accepted: 31 July 2018 / Published: 3 August 2018
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Abstract
Designing, changing and adapting organizations to secure viability is challenging for manufacturing companies. Researchers often fail to holistically design or transform production systems. Reasons are often the conflict of interests between production and maintenance, the temporal divergence of their activities and their organizational
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Designing, changing and adapting organizations to secure viability is challenging for manufacturing companies. Researchers often fail to holistically design or transform production systems. Reasons are often the conflict of interests between production and maintenance, the temporal divergence of their activities and their organizational structure. Thus, the aim of this study is to propose a holistic approach of how production and maintenance can be designed, changed or managed. Hereby, the Viable System Model was applied. This structure can be applied to any kind of structured organization and for its management with goals to be achieved in modern society; however, focus of the research is the coordination of production and maintenance management. The goal of the developed model is to be able to react to some potential production environments by taking coordinated decisions correctly and in the right moment based on the needed information. To ensure this, standardized communication channels were defined. In conclusion, this proposed approach enables production systems to have internal mechanisms to secure viability depending on all potential environment scenarios. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle The Influence of Manufacturing Parameters on the Mechanical Behaviour of PLA and ABS Pieces Manufactured by FDM: A Comparative Analysis
Materials 2018, 11(8), 1333; https://doi.org/10.3390/ma11081333
Received: 2 July 2018 / Revised: 27 July 2018 / Accepted: 30 July 2018 / Published: 1 August 2018
Cited by 1 | PDF Full-text (5462 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents a comparative study of the tensile mechanical behaviour of pieces produced using the Fused Deposition Modelling (FDM) additive manufacturing technique with respect to the two types of thermoplastic material most widely used in this technique: polylactide (PLA) and acrylonitrile butadiene
[...] Read more.
This paper presents a comparative study of the tensile mechanical behaviour of pieces produced using the Fused Deposition Modelling (FDM) additive manufacturing technique with respect to the two types of thermoplastic material most widely used in this technique: polylactide (PLA) and acrylonitrile butadiene styrene (ABS). The aim of this study is to compare the effect of layer height, infill density, and layer orientation on the mechanical performance of PLA and ABS test specimens. The variables under study here are tensile yield stress, tensile strength, nominal strain at break, and modulus of elasticity. The results obtained with ABS show a lower variability than those obtained with PLA. In general, the infill percentage is the manufacturing parameter of greatest influence on the results, although the effect is more noticeable in PLA than in ABS. The test specimens manufactured using PLA perform more rigidly and they are found to have greater tensile strength than ABS. The bond between layers in PLA turns out to be extremely strong and is, therefore, highly suitable for use in additive technologies. The methodology proposed is a reference of interest in studies involving the determination of mechanical properties of polymer materials manufactured using these technologies. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Influence of PLA Filament Conditions on Characteristics of FDM Parts
Materials 2018, 11(8), 1322; https://doi.org/10.3390/ma11081322
Received: 30 June 2018 / Revised: 27 July 2018 / Accepted: 28 July 2018 / Published: 31 July 2018
PDF Full-text (11407 KB) | HTML Full-text | XML Full-text
Abstract
Additive manufacturing technologies play an important role in Industry 4.0. One of the most prevalent processes is fused deposition modelling (FDM) due to its versatility and low cost. However, there is still a lack of standardization of materials and procedures within this technology.
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Additive manufacturing technologies play an important role in Industry 4.0. One of the most prevalent processes is fused deposition modelling (FDM) due to its versatility and low cost. However, there is still a lack of standardization of materials and procedures within this technology. This work aims to study the relationship of certain operating parameters and the conditions of poly(lactic acid) (PLA) polymer with the results of the manufactured parts in dimensional terms, surface quality, and mechanical strength. In this way, the impact of some material characteristics is analyzed, such as the pigmentation of the material and the environmental humidity where it has been stored. The manufacturing parameter that relates to these properties has been the extrusion temperature since it is the most influential in this technology. The results are quite affected especially by humidity, being a parameter little studied in the literature. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Replicability of Ultrasonic Molding for Processing Thin-Wall Polystyrene Plates with a Microchannel
Materials 2018, 11(8), 1320; https://doi.org/10.3390/ma11081320
Received: 6 July 2018 / Revised: 25 July 2018 / Accepted: 26 July 2018 / Published: 30 July 2018
PDF Full-text (6765 KB) | HTML Full-text | XML Full-text
Abstract
Ultrasonic molding is a new technology for processing small and micro polymeric components with reasonable cost and energy savings when small and medium batch sizes are required. However, when microcomponents are manufactured, the replicability of different micro features has to be guaranteed. The
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Ultrasonic molding is a new technology for processing small and micro polymeric components with reasonable cost and energy savings when small and medium batch sizes are required. However, when microcomponents are manufactured, the replicability of different micro features has to be guaranteed. The aim is to investigate the capability of ultrasonic molding technology for processing thin-wall plates of polystyrene with a microchannel, analyzing the filling behavior, the optical transparency, and the dimensional accuracy of the thin plate. The replicability of the manufactured microchannel is studied according to dimension and shape. The results reveal that plunger velocity influences transparency and filling cavity, whereas the vibration amplitude has less effect in both cases. The thickness deviation achieved on the final part is below 7% and the replication of the microchannel is better in depth than width, obtaining an average deviation of 4% and 11%, respectively. This replication also depends on the orientation of the microchannels and the distance from the injection gate. The replicability and repeatability for processing thin-wall plates with microchannel in polystyrene polymer are proved in this paper. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Open Source 3D Printed Lung Tumor Movement Simulator for Radiotherapy Quality Assurance
Materials 2018, 11(8), 1317; https://doi.org/10.3390/ma11081317
Received: 29 June 2018 / Revised: 19 July 2018 / Accepted: 26 July 2018 / Published: 30 July 2018
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Abstract
In OECD (Organization for Economic Co-operation and Development) countries, cancer is one of the main causes of death, lung cancer being one of the most aggressive. There are several techniques for the treatment of lung cancer, among which radiotherapy is one of the
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In OECD (Organization for Economic Co-operation and Development) countries, cancer is one of the main causes of death, lung cancer being one of the most aggressive. There are several techniques for the treatment of lung cancer, among which radiotherapy is one of the most effective and least invasive for the patient. However, it has associated difficulties due to the moving target tumor. It is possible to reduce the side effects of radiotherapy by effectively tracking a tumor and reducing target irradiation margins. This paper presents a custom electromechanical system that follows the movement of a lung tumor. For this purpose, a hysteresis loop of human lung movement during breathing was studied to obtain its characteristic movement equation. The system is controlled by an Arduino, steppers motors and a customized 3D printed mechanism to follow the characteristic human breathing, obtaining an accurate trajectory. The developed device helps the verification of individualized radiation treatment plans and permits the improvement of radiotherapy quality assurance procedures. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Single-Shot near Edge X-ray Fine Structure (NEXAFS) Spectroscopy Using a Laboratory Laser-Plasma Light Source
Materials 2018, 11(8), 1303; https://doi.org/10.3390/ma11081303
Received: 27 June 2018 / Revised: 13 July 2018 / Accepted: 25 July 2018 / Published: 28 July 2018
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Abstract
We present a proof of principle experiment on single-shot near edge soft X-ray fine structure (NEXAFS) spectroscopy with the use of a laboratory laser-plasma light source. The source is based on a plasma created as a result of the interaction of a nanosecond
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We present a proof of principle experiment on single-shot near edge soft X-ray fine structure (NEXAFS) spectroscopy with the use of a laboratory laser-plasma light source. The source is based on a plasma created as a result of the interaction of a nanosecond laser pulse with a double stream gas puff target. The laser-plasma source was optimized for efficient soft X-ray (SXR) emission from the krypton/helium target in the wavelength range from 2 nm to 5 nm. This emission was used to acquire simultaneously emission and absorption spectra of soft X-ray light from the source and from the investigated sample using a grazing incidence grating spectrometer. NEXAFS measurements in a transmission mode revealed the spectral features near the carbon K-α absorption edge of thin polyethylene terephthalate (PET) film and L-ascorbic acid in a single-shot. From these features, the composition of the PET sample was successfully obtained. The NEXAFS spectrum of the L-ascorbic acid obtained in a single-shot exposure was also compared to the spectrum obtained a multi-shot exposure and to numerical simulations showing good agreement. In the paper, the detailed information about the source, the spectroscopy system, the absorption spectra measurements and the results of the studies are presented and discussed. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Spiral Bevel Gears Face Roughness Prediction Produced by CNC End Milling Centers
Materials 2018, 11(8), 1301; https://doi.org/10.3390/ma11081301
Received: 6 June 2018 / Revised: 23 July 2018 / Accepted: 25 July 2018 / Published: 27 July 2018
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Abstract
The emergence of multitasking machines in the machine tool sector presents new opportunities for the machining of large size gears and short production series in these machines. However, the possibility of using standard tools in conventional machines for gears machining represents a technological
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The emergence of multitasking machines in the machine tool sector presents new opportunities for the machining of large size gears and short production series in these machines. However, the possibility of using standard tools in conventional machines for gears machining represents a technological challenge from the point of view of workpiece quality. Machining conditions in order to achieve both dimensional and surface quality requirements need to be determined. With these considerations in mind, computer numerical control (CNC) methods to provide useful tools for gear processing are studied. Thus, a model for the prediction of surface roughness obtained on the teeth surface of a machined spiral bevel gear in a multiprocess machine is presented. Machining strategies and optimal machining parameters were studied, and the roughness model is validated for 3 + 2 axes and 5 continuous axes machining strategies. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Study on Near-Net Forming Technology for Stepped Shaft by Cross-Wedge Rolling Based on Variable Cone Angle Billets
Materials 2018, 11(8), 1278; https://doi.org/10.3390/ma11081278
Received: 30 June 2018 / Revised: 17 July 2018 / Accepted: 18 July 2018 / Published: 25 July 2018
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Abstract
Considering problems about concaves at the stepped shaft ends, this paper established the plastic flow kinetic theories about metal deforming during the cross-wedge rolling (CWR) process. By means of the DEFORM-3D finite element software and the point tracing method, the forming process of
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Considering problems about concaves at the stepped shaft ends, this paper established the plastic flow kinetic theories about metal deforming during the cross-wedge rolling (CWR) process. By means of the DEFORM-3D finite element software and the point tracing method, the forming process of stepped shafts and the forming mechanism of concaves at shaft ends were studied. Based on the forming features of stepped shafts, rolling pieces were designed using variable cone angle billets. Single-factor tests were conducted to analyze the influence law of the shape parameters of billet with variable cone angle on end concaves, and rolling experiments were performed for verification. According to the results, during the rolling process of stepped shafts, concaves will come into being in stages, and the increasing tendency of its depth is due to the wave mode, the parameters of cone angle α, the first cone section length n. Furthermore, the total cone section length m has an increasingly weaker influence on the end concaves. Specifically, cone angle α has the most significant influence on the quality of shaft ends, which is about twice the influence of the total cone section length m. The concave depth will decrease at the beginning, and then increase with the increasing of the cone angle α and the first cone section length n, and it will decrease with the increasing of the total cone section length m. Finite element numerical analysis results are perfectly consistent with experimental results, with the error ratio being lower than 5%. The results provide a reliable theoretical basis for effectively disposing of end concave problems during CWR, rationally confirming the shape parameters of billets with a variable cone angle, improving the quality of stepped shaft ends, and realizing the near-net forming process of cross-wedge rolling without a stub bar. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Tool Wear Mechanism in Cutting of Stack CFRP/UNS A97075
Materials 2018, 11(8), 1276; https://doi.org/10.3390/ma11081276
Received: 1 July 2018 / Revised: 19 July 2018 / Accepted: 23 July 2018 / Published: 25 July 2018
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Abstract
The aeronautics industry’s competitiveness has led to the need to increase productivity with one shot drilling (OSD) systems capable of drilling stacks of dissimilar materials (fibre/metal laminates, FML) in order to reduce riveting times. Among the materials that constitute the current aeronautical models,
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The aeronautics industry’s competitiveness has led to the need to increase productivity with one shot drilling (OSD) systems capable of drilling stacks of dissimilar materials (fibre/metal laminates, FML) in order to reduce riveting times. Among the materials that constitute the current aeronautical models, composite materials and aluminium (Al) and titanium (Ti) alloys stand out. These one-pass machining techniques produce high-quality holes, especially when all the elements that have to be joined are made of the same material. This work has followed a conventional OSD strategy and the same cutting conditions applied to CFRP (carbo-fibre-reinforced polymer), Al and CFRP/Al stacked sheets to know the wear mechanisms produced. With this purpose, results were obtained by using current specific techniques, such as microstructural analysis, monitoring of the shear forces and analysis of macrogeometric deviations. It has been determined that when these drilling techniques are applied under the same cutting conditions to stacks of materials of a different nature, the results of the wear mechanisms acting on the tool differ from those obtained when machining each material separately. This article presents a comparison between the effects of tool wear during dry drilling of CFRP and UNS A97075 plates separately and when machined as stacks. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Evaluation of the Functional Performance in Turned Workpieces: Methodology and Application to UNS A92024-T3
Materials 2018, 11(8), 1264; https://doi.org/10.3390/ma11081264
Received: 29 June 2018 / Revised: 18 July 2018 / Accepted: 20 July 2018 / Published: 24 July 2018
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Abstract
Turning of light alloys as aluminum-based UNS A92024-T3 is broadly implemented in the manufacture of critical aircraft parts, so ensuring a good functional performance of these pieces is essential. Moreover, operational conditions of these pieces include saline environments where corrosion processes are present.
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Turning of light alloys as aluminum-based UNS A92024-T3 is broadly implemented in the manufacture of critical aircraft parts, so ensuring a good functional performance of these pieces is essential. Moreover, operational conditions of these pieces include saline environments where corrosion processes are present. In this paper, a methodology for the evaluation of the functional performance in turned pieces is proposed. Specimens affected and not affected by corrosion are compared. In addition, performance in service through tensile stress tests of these parts is considered. The results show that turning improves the functional performance of UNS A92024-T3 alloy and that corrosion can enhance the mechanical properties of this alloy. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Experimental Parametric Relationships for Chip Geometry in Dry Machining of the Ti6Al4V Alloy
Materials 2018, 11(7), 1260; https://doi.org/10.3390/ma11071260
Received: 27 June 2018 / Revised: 16 July 2018 / Accepted: 18 July 2018 / Published: 23 July 2018
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Abstract
The Ti6Al4V alloy is included in the group of difficult-to-cut materials. Segmented chips are generated for a wide range of cutting parameters. This kind of chip geometry leads to the periodic variation of machining forces, tool vibrations, and work part-tolerance inaccuracies. Therefore, the
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The Ti6Al4V alloy is included in the group of difficult-to-cut materials. Segmented chips are generated for a wide range of cutting parameters. This kind of chip geometry leads to the periodic variation of machining forces, tool vibrations, and work part-tolerance inaccuracies. Therefore, the analysis of chip morphology and geometry becomes a fundamental machinability criterion. However, few studies propose experimental parametric relationships that allow predicting chip-geometry evolution as a function of cutting parameters. In this work, an experimental analysis of the influence of cutting speed and feed rate on various chip-geometric parameters in dry machining of the Ti6Al4V alloy was carried out. In addition, the chip morphology and chip microstructure were studied. A clear dependence of certain chip-geometric parameters on the cutting parameters studied was found. From the experimental data, several parametric relationships were developed. These relationships were able to predict the evolution of different geometric parameters as a function of cutting speed and feed, within the tested range of values. The differences between the proposed models and the experimental data were also highlighted. These parametric equations allowed quantifying the value of parameters in which the trend was clear. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Combination of Laser Material Deposition and Laser Surface Processes for the Holistic Manufacture of Inconel 718 Components
Materials 2018, 11(7), 1247; https://doi.org/10.3390/ma11071247
Received: 27 June 2018 / Revised: 17 July 2018 / Accepted: 18 July 2018 / Published: 20 July 2018
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Abstract
The present work proposes a novel manufacturing technique based on the combination of Laser Metal Deposition, Laser Beam Machining, and laser polishing processes for the complete manufacturing of complex parts. Therefore, the complete process is based on the application of a laser heat
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The present work proposes a novel manufacturing technique based on the combination of Laser Metal Deposition, Laser Beam Machining, and laser polishing processes for the complete manufacturing of complex parts. Therefore, the complete process is based on the application of a laser heat source both for the building of the preform shape of the part by additive manufacturing and for the finishing operations. Their combination enables the manufacture of near-net-shape parts and afterwards removes the excess material via laser machining, which has proved to be capable of eliminating the waviness resulting from the additive process. Besides, surface quality is improved via laser polishing so that the roughness of the final part is reduced. Therefore, conventional machining operations are eliminated, which results in a much cleaner process. To validate the capability of this new approach, the dimensional accuracy and surface quality as well as the microstructure of the resulting parts are evaluated. The process has been validated on an Inconel 718 test part, where a previously additively built-up part has been finished by means of laser machining and laser polishing. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Application of Pin-On-Disc Techniques for the Study of Tribological Interferences in the Dry Machining of A92024-T3 (Al–Cu) Alloys
Materials 2018, 11(7), 1236; https://doi.org/10.3390/ma11071236
Received: 28 June 2018 / Revised: 15 July 2018 / Accepted: 17 July 2018 / Published: 18 July 2018
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Abstract
One of the main criteria for the establishment of the performance of a forming process by material removal is based on cutting tool wear. Wear is usually caused by different mechanisms, however, only one is usually considered as predominant or the controller of
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One of the main criteria for the establishment of the performance of a forming process by material removal is based on cutting tool wear. Wear is usually caused by different mechanisms, however, only one is usually considered as predominant or the controller of the process. This experimental research is focused on the application of Pin-on-Disc wear tests, in which the tribological interference between UNS A92024-T3 Aluminum–Copper alloy and tungsten carbide (WC–Co) has been studied. The main objective of this study is focused on the determination of the predominant wear mechanisms involved in the process, as well as the characterization of the sliding and friction effects by using SEM and Energy Dispersion Spectroscopy (EDS) techniques, as applied to WC–Co (cutting tool material)/Al (workpiece material) which are widely used in the aerospace industry. Performed analysis prove the appearance of abrasive wear mechanisms prior to adhesion. This fact promotes adhesion mechanisms in several stages because of the surface quality deterioration, presenting different alloy composition in the form of a Built-Up Layer (BUL)/Built-Up Edge (BUE). Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle On the Performance of Thin-Walled Crash Boxes Joined by Forming
Materials 2018, 11(7), 1118; https://doi.org/10.3390/ma11071118
Received: 7 June 2018 / Revised: 26 June 2018 / Accepted: 28 June 2018 / Published: 29 June 2018
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Abstract
A new joining by forming process that combines lancing and shearing with sheet-bulk compression is utilized to assemble thin-walled crash boxes utilized as energy absorbers. Process design and fabrication of the new crash boxes are analyzed by finite elements and experimentation. Axial crush
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A new joining by forming process that combines lancing and shearing with sheet-bulk compression is utilized to assemble thin-walled crash boxes utilized as energy absorbers. Process design and fabrication of the new crash boxes are analyzed by finite elements and experimentation. Axial crush tests were performed to compare the overall crashworthiness performance of the new crash boxes against that of conventional crash boxes assembled by resistance spot-welding. Results show that the joining process is a good alternative to resistance spot-welding because the new crash boxes can absorb the same crushing energy, and because the new process helps to overcome typical manufacturing problems of welding. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Unexpected Event Prediction in Wire Electrical Discharge Machining Using Deep Learning Techniques
Materials 2018, 11(7), 1100; https://doi.org/10.3390/ma11071100
Received: 13 June 2018 / Revised: 25 June 2018 / Accepted: 26 June 2018 / Published: 28 June 2018
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Abstract
Theoretical models of manufacturing processes provide a valuable insight into physical phenomena but their application to practical industrial situations is sometimes difficult. In the context of Industry 4.0, artificial intelligence techniques can provide efficient solutions to actual manufacturing problems when big data are
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Theoretical models of manufacturing processes provide a valuable insight into physical phenomena but their application to practical industrial situations is sometimes difficult. In the context of Industry 4.0, artificial intelligence techniques can provide efficient solutions to actual manufacturing problems when big data are available. Within the field of artificial intelligence, the use of deep learning is growing exponentially in solving many problems related to information and communication technologies (ICTs) but it still remains scarce or even rare in the field of manufacturing. In this work, deep learning is used to efficiently predict unexpected events in wire electrical discharge machining (WEDM), an advanced machining process largely used for aerospace components. The occurrence of an unexpected event, namely the change of thickness of the machined part, can be effectively predicted by recognizing hidden patterns from process signals. Based on WEDM experiments, different deep learning architectures were tested. By using a combination of a convolutional layer with gated recurrent units, thickness variation in the machined component could be predicted in 97.4% of cases, at least 2 mm in advance, which is extremely fast, acting before the process has degraded. New possibilities of deep learning for high-performance machine tools must be examined in the near future. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Open AccessArticle Effect of Temperature Distribution in Ultrasonically Welded Joints of Copper Wire and Sheet Used for Electrical Contacts
Materials 2018, 11(6), 1010; https://doi.org/10.3390/ma11061010
Received: 31 May 2018 / Revised: 9 June 2018 / Accepted: 12 June 2018 / Published: 14 June 2018
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Abstract
The temperature distribution occurring at the interface while joining a simple electrical contact comprising of a copper wire and a copper sheet using ultrasonic metal welding was analyzed using finite element method. Heat flux due to plastic deformation and friction was calculated and
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The temperature distribution occurring at the interface while joining a simple electrical contact comprising of a copper wire and a copper sheet using ultrasonic metal welding was analyzed using finite element method. Heat flux due to plastic deformation and friction was calculated and provided as input load for simulation of temperature distribution. The results of temperature obtained from simulation are found to be in good agreement with the results of temperature from experiments measured using thermocouple. Special focus was given to how the heat generated at the wire–sheet interface affect the strength of the joint in tension. With the knowledge of heat generated at the interface while welding, it is possible to control the strength of the joint and produce defect free joints. Based on the results from finite element analysis and experiments, it is observed that the influence of heat developed due to friction and plastic deformation of metallic specimens has a significant effect on the progress of welding and strength of the joint. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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Jump to: Research

Open AccessConcept Paper Accelerating High-Throughput Screening for Structural Materials with Production Management Methods
Materials 2018, 11(8), 1330; https://doi.org/10.3390/ma11081330
Received: 5 July 2018 / Revised: 26 July 2018 / Accepted: 30 July 2018 / Published: 1 August 2018
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Abstract
High-throughput screenings are widely accepted for pharmaceutical developments for new substances and the development of new drugs with required characteristics by evolutionary studies. Current research projects transfer this principle of high-throughput testing to the development of metallic materials. In addition to new generating
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High-throughput screenings are widely accepted for pharmaceutical developments for new substances and the development of new drugs with required characteristics by evolutionary studies. Current research projects transfer this principle of high-throughput testing to the development of metallic materials. In addition to new generating and testing methods, these types of high-throughput systems need a logistical control and handling method to reduce throughput time to get test results faster. Instead of the direct material flow found in classical high-throughput screenings, these systems have a very complex structure of material flow. The result is a highly dynamic system that includes short-term changes such as rerun stations, partial tests, and temporarily paced sequences between working systems. This paper presents a framework that divides the actions for system acceleration into three main sections. First, methods for special applications in high-throughput systems are designed or adapted to speed up the generation, treatment, and testing processes. Second, methods are needed to process trial plans and to control test orders, which can efficiently reduce waiting times. The third part of the framework describes procedures for handling samples. This reduces non-productive times and reduces order processing in individual lots. Full article
(This article belongs to the Special Issue Special Issue of the Manufacturing Engineering Society (MES))
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