Special Issue "The High Efficiency Machining Process and Machining of Complex Materials"

A special issue of Applied Sciences (ISSN 2076-3417). This special issue belongs to the section "Mechanical Engineering".

Deadline for manuscript submissions: closed (31 December 2019).

Special Issue Editors

Dr. Moises Batista
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Guest Editor
Department of Mechanical Engineering and Industrial Design, School of Engineering, University of Cadiz, E11519 Puerto Real, Spain
Interests: mechanical engineering, conventional and non-conventional machining, tool wear, machining tribology
Special Issues and Collections in MDPI journals
Dr. Severo Raul Fernandez-Vidal
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Guest Editor
Department of Mechanical Engineering and Industrial Design, University of Cadiz, School of Engineering, Campus de Puerto Real
Interests: mechanical engineering, conventional and non-conventional machining, tool wear, machining tribology
Prof. Dr. Jorge Salguero
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Guest Editor
Faculty of Engineering, Department of Mechanical Engineering and Industrial Design, University of Cadiz. Adva. Universidad de Cadiz 10, E11519 Puerto Real, Spain
Interests: machining; tool wear; tribology; laser texturing; surface engineering; light alloys
Special Issues and Collections in MDPI journals
Prof. Dr. Joao Paulo Davim
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Guest Editor
Department of Mechanical Engineering, University of Aveiro, Campus Santiago, 3810-193 Aveiro, Portugal
Interests: mechanical and industrial engineering; materials; machining; tribology; sustainable manufacturing; higher education for sustainability; engineering education
Special Issues and Collections in MDPI journals

Special Issue Information

Dear Colleagues,

The industrial production is undergoing some pragmatics changes. These changes are defined by key enabling technologies, also known as KET, implying a turning point in our understanding the production.

In this way, the production must be adapted to new performance models, where all the elements involved in the production system must improve their role in the best possible way. In other words, the production system must increase its efficiency significantly.

Traditionally, machining processes are a production operation in which the efficiency is generally low. Therefore, the search for a high efficiency machining process is a strategic necessity for the industry.

On top of that, the industry has the need to use complex, high-performance materials, which requires high-efficiency processes in order to improve the overall outcome.

This Special Issue is open to advances in the following two aspects: the improvement of the efficiency of the machining processes and the advancement of the use of complex materials in the machining process, involving the following:

  • An mproved, efficient machining process (conventional and non-conventional);
  • A new, high-efficiency machining process;
  • Traditional machining applied to complex materials;
  • New machining processes applied to complex materials;
  • Improved, efficient machining of complex materials;
  • The application of a KET to improve the machining process;
  • New tools, new characterization methods, and tool wear control;
  • An adaptive machining process;
  • Improvement of the performance of the machining process;
  • A hybrid machining process.

Dr. Moises Batista
Dr. Severo Raul Fernandez-Vidal
Dr. Jorge Salguero
Prof. Dr. J. Paulo Davim
Guest Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 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

  • Machining
  • Complex materials
  • Improved efficiency
  • Performance

Published Papers (14 papers)

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Research

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Open AccessArticle
Characterization and Defect Analysis of Machined Regions in Al-SiC Metal Matrix Composites Using an Abrasive Water Jet Machining Process
Appl. Sci. 2020, 10(4), 1512; https://doi.org/10.3390/app10041512 - 23 Feb 2020
Cited by 3
Abstract
Metal matrix composite (MMC) materials are increasingly used in industrial sectors such as energy, structural, aerospace, and automotive. This is due to the improvement of properties by the addition of reinforcements. Thus, it is possible to obtain properties of higher strength, better rigidity, [...] Read more.
Metal matrix composite (MMC) materials are increasingly used in industrial sectors such as energy, structural, aerospace, and automotive. This is due to the improvement of properties by the addition of reinforcements. Thus, it is possible to obtain properties of higher strength, better rigidity, controlled thermal expansion, and elevated wear resistance. However, due to the extreme hardness achieved during their manufacture, these composites pose a challenge to the conventional machining industry due to the rapid deterioration experienced by cutting tools. This article therefore proposes the use of an unconventional machining method that is becoming increasingly widely used: abrasive water jet cutting. This process is characterized by high production rates, absence of wear, and environmental friendliness, among other advantages. Experimental tests were carried out in order to analyze results that minimize the formation of defects in the machining of metal matrix composite consisting of aluminium matrix with silicon carbide (Al-SiC MMC). To this end, results were analyzed using Scanning Optical and Electron Microscope (SOM/SEM) techniques, the taper angle was calculated, and areas with different surface quality were detected by measuring the roughness. Full article
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Open AccessArticle
Study of the Influence of Helical Milling Parameters on the Quality of Holes in the UNS R56400 Alloy
Appl. Sci. 2020, 10(3), 845; https://doi.org/10.3390/app10030845 - 24 Jan 2020
Cited by 1
Abstract
Helical milling has been positioned as an alternative to conventional drilling, where the advantages it offers make it very attractive for use on difficult-to-machine alloys such as the titanium alloy UNS R56400. However, the correlation between the indicator of hole quality and the [...] Read more.
Helical milling has been positioned as an alternative to conventional drilling, where the advantages it offers make it very attractive for use on difficult-to-machine alloys such as the titanium alloy UNS R56400. However, the correlation between the indicator of hole quality and the kinematic parameters has rarely been studied. The kinematics are what bring most advantages and that is why it is necessary to know their influence. In this aspect, there are different focuses of problems associated with the complexity of the process kinematics, which makes it necessary to undertake a deeper analysis of the process and to carry out a preliminary study. To address this problem, a DOE (Design of Experiments) is proposed to identify the sensitivity and the main trends of the properties that define the quality holes with respect to the kinematic parameters. At the same time, a nomenclature is proposed to unify and avoid misinterpretations. This study has allowed us to obtain conclusive results that offer very relevant information for future research Full article
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Open AccessArticle
Properties of the Surface Layer After Trochoidal Milling and Brushing: Experimental Study and Artificial Neural Network Simulation
Appl. Sci. 2020, 10(1), 75; https://doi.org/10.3390/app10010075 - 20 Dec 2019
Abstract
The aim of this study was to investigate the effect of milling and brushing cutting data settings on the surface geometry and energy parameters of two Mg alloy substrates: AZ91D and AZ31. In milling, the cutting speed and the trochoidal step were modified [...] Read more.
The aim of this study was to investigate the effect of milling and brushing cutting data settings on the surface geometry and energy parameters of two Mg alloy substrates: AZ91D and AZ31. In milling, the cutting speed and the trochoidal step were modified (vc = 400–1200 m/min and str = 5–30%) to investigate how they affect selected 2D (Rz, Rku, Rsk, RSm, Ra) and 3D (Sa, Sz, Sku, Ssk) roughness parameters. The brushing treatment was carried out at constant parameters: n = 5000 rev/min, vf = 300 mm/min, ap = 0.5 mm. The surface roughness of specimens was assessed with the Ra, Rz, and RSm parameters. The effects of the two treatments on the workpiece surface were analyzed comparatively. It was found that the roughness properties of the machined surface may be improved by the application of a carbide milling cutter and ceramic brush. The use of different machining data was also shown to impact the surface free energy and its polar component of Mg alloy specimens. Complementary to the results from the experimental part of the study, the investigated machining processes were modelled by means of statistical artificial neural networks (the radial basis function and multi-layered perceptron). The artificial neural networks (ANNs) were shown to perform well as a tool for the prediction of Mg alloy surface roughness parameters and the maximum height of the profile (Rz) after milling and brushing. Full article
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Open AccessArticle
Experimental and Numerical Study of Edge Defects When Turning 17vol.% SiCp/2009Al Composites
Appl. Sci. 2019, 9(18), 3817; https://doi.org/10.3390/app9183817 - 11 Sep 2019
Cited by 2
Abstract
In this work, a three-dimensional large-deformation thermo-elastic-plastic finite element model for oblique cutting was established to analyze edge defects during the machining of 17vol.% SiCp/2009Al composites. The formation process of edge defects at the workpiece exit during turning was investigated, and [...] Read more.
In this work, a three-dimensional large-deformation thermo-elastic-plastic finite element model for oblique cutting was established to analyze edge defects during the machining of 17vol.% SiCp/2009Al composites. The formation process of edge defects at the workpiece exit during turning was investigated, and the influence of depth of cut, feed rate, and spindle speed on the edge defect sizes at the workpiece exit was explored. The results show that a negative deformation plane began to form as the cutting tool approached the exit end of cut, and the resultant cracks propagated towards the negative shear deformation plane, which led to workpiece edge defects. In addition, the size of edge defects increased with increasing depth of cut and feed rate, while the spindle speed had less influence on the size of edge defects. The numerical results of the effects of cutting parameters on edge defects were also compared to those of the turning experimental data, and were found to be in reasonable agreement. Full article
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Open AccessArticle
Contrast Experiments in Dielectrophoresis Polishing (DEPP)/Chemical Mechanical Polishing (CMP) of Sapphire Substrate
Appl. Sci. 2019, 9(18), 3704; https://doi.org/10.3390/app9183704 - 06 Sep 2019
Cited by 1
Abstract
The broad applications of sapphire substrates in many fields warrants an urgent demand for a highly efficient and high precision polishing method for the sapphire substrates. The authors proposed a novel sapphire substrate polishing method that is based on the dielectrophoresis (DEP) effect. [...] Read more.
The broad applications of sapphire substrates in many fields warrants an urgent demand for a highly efficient and high precision polishing method for the sapphire substrates. The authors proposed a novel sapphire substrate polishing method that is based on the dielectrophoresis (DEP) effect. The principle of dielectrophoresis polishing (DEPP) is described. A non-uniform electric field was added in the polishing area to drive abrasives moving in the direction towards the plate by the DEP force. The amount of abrasives that participates in the polishing action increases as the distribution of polishing slurry on sapphire surface changes, leading towards the improvement of sapphire polishing both in quality and efficiency. Comparative experiments between DEPP and traditional chemical mechanical polishing (CMP) were carried out. It was found that the maximum increase of sapphire MRR for DEPP is 71%, reaching 13 mg/h, and the minimum increase was 9.5%, reaching 4.6 mg/h. The surface roughness of the sapphire substrate decreases faster and more uniform with DEPP. The final surface roughness of the sapphire substrate after DEPP was Ra 0.87 nm and the flatness was 0.3078 waves (RMS value), which is better than 0.6863 waves (RMS value) of sapphire substrate with traditional CMP polishing. Full article
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Open AccessArticle
A Dedicated Design Strategy for Active Boring Bar
Appl. Sci. 2019, 9(17), 3541; https://doi.org/10.3390/app9173541 - 28 Aug 2019
Cited by 2
Abstract
Unstable vibrations (i.e., chatter) onset is one of the main limits to productivity in deep boring bar processes. Active damping systems allow to increase machining stability in different configurations (i.e., tool setup), without requiring cutting system dynamic characterization. Design of an active boring [...] Read more.
Unstable vibrations (i.e., chatter) onset is one of the main limits to productivity in deep boring bar processes. Active damping systems allow to increase machining stability in different configurations (i.e., tool setup), without requiring cutting system dynamic characterization. Design of an active boring bar involves the development of monitoring system (sensors), actuation system and control logic. While several control logics were evaluated and discussed, few design solutions were presented in the literature, focusing only on building prototypes to demonstrate control logic effectiveness. In the presented work, a deep analysis of the main issues and requirements related to active boring design was carried out and a systematic approach to tackle all the critical aspects was developed. The results of the proposed method are: (i) optimal actuators positioning able to damp vibration along two directions; (ii) preload system design guaranteeing the correct actuator preloading for the operating conditions; (iii) covers design to protect actuators and ensure the dynamic and static equivalence between active and standard boring bar. Following this approach, an active boring bar was designed, realized and tested. The results prove the required equivalence between active and original boring bar and assess the damping effect. Full article
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Open AccessArticle
A Study on the Deformation Behavior of a Microstructure Depending on Its Shape and the Cutting Section in the Precision Cutting of a Functional Part
Appl. Sci. 2019, 9(14), 2940; https://doi.org/10.3390/app9142940 - 23 Jul 2019
Abstract
The shape accuracy of microstructures is an important factor that directly affects the quality and performance of products. Nevertheless, it is difficult to find a study for the shape accuracy of microstructures below several microns. This study aimed to reduce the shape error [...] Read more.
The shape accuracy of microstructures is an important factor that directly affects the quality and performance of products. Nevertheless, it is difficult to find a study for the shape accuracy of microstructures below several microns. This study aimed to reduce the shape error in the precision machining of microstructures with a repeated triangular cross-sectional shape with a width of 5 µm or less. Two important factors in this study were the morphological features of the microstructure to be fabricated and the cross-sectional shape of the chip. The tool path was modified in consideration of these two factors. Before the tool path change, the shape error due to the deformation of the triangular micropattern in a DOC (depth of a cut) of 1 µm was about 0.39 µm. However, after the tool path was modified, the shape error due to deformation did not occur while maintaining the DOC at 1 µm. Full article
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Open AccessArticle
Study on the Design and Cutting Performance of a Revolving Cycloid Milling Cutter
Appl. Sci. 2019, 9(14), 2915; https://doi.org/10.3390/app9142915 - 21 Jul 2019
Cited by 1
Abstract
Problems such as low machining efficiency, severe tool wear and difficulty in safeguarding surface quality always exist in the machining process of titanium alloy with ball-end milling cutters. To address these issues, the design and manufacture of a revolving cycloid milling cutter for [...] Read more.
Problems such as low machining efficiency, severe tool wear and difficulty in safeguarding surface quality always exist in the machining process of titanium alloy with ball-end milling cutters. To address these issues, the design and manufacture of a revolving cycloid milling cutter for titanium alloy processing were studied in this paper. Firstly, the mathematical model of the revolving cycloid milling cutter contour surface was established. The parametric equation of an orthogonal helix cutting edge curve of a revolving cycloid milling cutter is presented. Then, the bottom boundary curve of the rake face is introduced. The five-axis grinding trajectory equation of revolving cycloid milling cutter rake face was derived based on the edge curve equation and coordinate transformation. Next, fabricating the revolving cycloid milling cutter and detecting the grinding accuracy of tool profile and geometric angle were performed. At last, a contrast test regarding the performance of the revolving cycloid milling cutter and the ball-end milling cutter in cutting titanium alloy TC11 was carried out. According to the test results, in comparison to the ball-end milling cutter, the revolving cycloid milling cutter had a smaller ratio of the axial force to the tangential force. Moreover, its flank face wore more slowly and evenly. As a result, a good surface processing quality can be maintained even under larger wear conditions, demonstrating an outstanding cutting performance. Full article
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Open AccessArticle
Cutting Force and Cutting Quality during Tapered Milling of Glass Magnesium Board
Appl. Sci. 2019, 9(12), 2533; https://doi.org/10.3390/app9122533 - 21 Jun 2019
Cited by 1
Abstract
In this paper, the effects of tool geometry and cutting parameters on cutting force and quality were investigated during the tapered milling of glass magnesium (MGO) board with diamond cutters. The results were as follows: firstly, both the cutting force and roughness of [...] Read more.
In this paper, the effects of tool geometry and cutting parameters on cutting force and quality were investigated during the tapered milling of glass magnesium (MGO) board with diamond cutters. The results were as follows: firstly, both the cutting force and roughness of the machined surface were positively correlated with the taper angle of the cutters and the cutting depth, but negatively related to the spindle speed. Then, the cutting depth had the largest influence on the cutting force and surface roughness, followed by the taper angle and spindle speed. Thirdly, the taper angle had a significant influence on the cutting force, but not on the surface roughness. The contribution of the spindle speed to both the cutting force and the surface roughness were significant, while the cutting depth had an insignificant effect on the cutting force and the surface roughness. Finally, the optimal cutting condition for the tapered milling of glass magnesium board was found to be a taper angle of 15°, a spindle speed of 5000 rpm (cutting speed of 36.63 m/s), and a cutting depth of 0.5 mm, which are proposed for industrial production in order to achieve greater cutting quality and economic benefit. Full article
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Open AccessArticle
Machinability of Stone—Plastic Materials During Diamond Planing
Appl. Sci. 2019, 9(7), 1373; https://doi.org/10.3390/app9071373 - 01 Apr 2019
Cited by 5
Abstract
This paper investigated the machinability of a stone–plastic composite (SPC) via orthogonal cutting with diamond cutters. The objective was to determine the effect of cutting depth on its machinability, including cutting forces, heat, chip formation, and cutting quality. Increased cutting depth promoted an [...] Read more.
This paper investigated the machinability of a stone–plastic composite (SPC) via orthogonal cutting with diamond cutters. The objective was to determine the effect of cutting depth on its machinability, including cutting forces, heat, chip formation, and cutting quality. Increased cutting depth promoted an increase in both frictional and normal forces, and also had a strong influence on the change in normal force. The cutting temperatures of chips and tool edges showed an increasing trend as cutting depth increased. However, the cutting heat was primarily absorbed by chips, with the balance accumulating in the cutting edge. During chip formation, the highest von Mises strain was mainly found in SPC ahead of the cutting edge, and the SPC to be removed partially passed its elastic limit, eventually forming chips with different shapes. Furthermore, the average surface roughness and the mean peak-to-valley height of machined surfaces all positively correlated to an increase in cutting depth. Finally, with an increase in cutting depth, the chip shape changed from tubular, to ribbon, to arc, to segmental, and finally, to helical chips. This evolution in chip shape reduced the fluctuation in cutting force, improving cutting stability and cutting quality. Full article
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Open AccessArticle
Optimization of Replaced Grinding Wheel Diameter for Minimum Grinding Cost in Internal Grinding
Appl. Sci. 2019, 9(7), 1363; https://doi.org/10.3390/app9071363 - 31 Mar 2019
Cited by 7
Abstract
This paper shows an optimization study on calculating the optimum replaced wheel diameter in internal grinding of stainless steel. In this work, the effects of the input factors, including the initial diameter, the grinding wheel width, the ratio between the length and the [...] Read more.
This paper shows an optimization study on calculating the optimum replaced wheel diameter in internal grinding of stainless steel. In this work, the effects of the input factors, including the initial diameter, the grinding wheel width, the ratio between the length and the diameter of the work-pieces, the dressing depth of cut, the wheel life and the radial grinding wheel wear per dress on the optimum replaced grinding wheel diameter were considered. Also, the effects of cost components, including the cost of the grinding machine and the wheel cost were examined. Moreover, to estimate the influences of these parameters on the optimum replaced diameter, a simulation experiment was given and conducted by programming. From the results of the study, a regression equation was proposed to calculate the optimum replaced diameter. Full article
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Open AccessArticle
Enhancement of the Localization Effect during Electrochemical Machining of Inconel 718 by Using an Alkaline Solution
Appl. Sci. 2019, 9(4), 690; https://doi.org/10.3390/app9040690 - 18 Feb 2019
Cited by 6
Abstract
Electrochemical machining (ECM) is a cost-effective method for the machining of difficult-to-cut Inconel 718 superalloy. However, the machining accuracy of ECM is still limited by the poor localization effect due to the existence of stray corrosion. In this paper, a mixed solution of [...] Read more.
Electrochemical machining (ECM) is a cost-effective method for the machining of difficult-to-cut Inconel 718 superalloy. However, the machining accuracy of ECM is still limited by the poor localization effect due to the existence of stray corrosion. In this paper, a mixed solution of neutral NaNO3 and alkaline NaOH is used to improve the localization effect during ECM of Inconel 718. The potentiodynamic polarization curves and current efficiencies for metal dissolution are measured, and the micro morphologies are examined. The results show that the use of an alkaline solution can promote the formation of a compact passive film on the surface of Inconel 718. ECM tests with cylindrical electrodes are specially designed to verify the effect of alkaline solution on the localization of anodic dissolution. The experimental results indicated that the stray corrosion of the non-machined surface of Inconel 718 alloy can be effectively eliminated by using a mixed solution of NaNO3 and NaOH. The surface roughness of the non-machined area can be noticeably improved. Full article
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Review

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Open AccessReview
Prediction Methods and Experimental Techniques for Chatter Avoidance in Turning Systems: A Review
Appl. Sci. 2019, 9(21), 4718; https://doi.org/10.3390/app9214718 - 05 Nov 2019
Cited by 5
Abstract
The general trend towards lightweight components and stronger but difficult to machine materials leads to a higher probability of vibrations in machining systems. Amongst them, chatter vibrations are an old enemy for machinists with the most dramatic cases resulting in machine-tool failure, accelerated [...] Read more.
The general trend towards lightweight components and stronger but difficult to machine materials leads to a higher probability of vibrations in machining systems. Amongst them, chatter vibrations are an old enemy for machinists with the most dramatic cases resulting in machine-tool failure, accelerated tool wear and tool breakage or part rejection due to unacceptable surface finish. To avoid vibrations, process designers tend to command conservative parameters limiting productivity. Among the different machining processes, turning is responsible of a great amount of the chip volume removed worldwide. This paper reports some of the main efforts from the scientific literature to predict stability and to avoid chatter with special emphasis on turning systems. There are different techniques and approaches to reduce and to avoid chatter effects. The objective of the paper is to summarize the current state of research in this hot topic, particularly (1) the mechanistic, analytical, and numerical methods for stability prediction in turning; (2) the available techniques for chatter detection and control; (3) the main active and passive techniques. Full article
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Open AccessReview
Review of Machining Equipment Reliability Analysis Methods based on Condition Monitoring Technology
Appl. Sci. 2019, 9(14), 2786; https://doi.org/10.3390/app9142786 - 11 Jul 2019
Cited by 2
Abstract
The condition of mechanical equipment during machining is closely related to the accuracy and roughness of the workpiece. In an intelligent sensing environment, a large amount of multi-source data reflecting status information are generated during processing, and a number of studies have been [...] Read more.
The condition of mechanical equipment during machining is closely related to the accuracy and roughness of the workpiece. In an intelligent sensing environment, a large amount of multi-source data reflecting status information are generated during processing, and a number of studies have been conducted for machining equipment reliability analysis. In this paper, the reliability analysis method of machining equipment based on condition monitoring technology is taken as the main line. And an up-to-date comprehensive survey of multi-source information during the cutting process, failure physical analysis for signal selection and reliability assessment based on condition information will be provided. Finally, the future challenges and trends will also be presented. It is a feasible and valuable research direction to evaluate the reliability of machining equipment for product quality characteristics. Full article
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