Special Issue "Precision Machining"

A special issue of Machines (ISSN 2075-1702).

Deadline for manuscript submissions: closed (28 February 2018)

Special Issue Editor

Guest Editor
Prof. Dr. Angelos P. Markopoulos

Section of Manufacturing Technology, School of Mechanical Engineering, National Technical University of Athens
Website | E-Mail
Interests: precision machining; micromachining; non-conventional machining; grinding; nano-manufacturing; cutting tools; difficult-to-machine materials; finite elements simulation; molecular dynamics; soft computing; nanomaterials

Special Issue Information

Dear Colleagues,

Material removal processes are considered exceptionally important manufacturing methods used, worldwide, for the production of mechanical components. A key feature of these processes is their ability to produce final products with high accuracy and of high quality. Conventional and non-conventional machining, as well as abrasive processes, are vital for the production of high quality components from many different materials categories. Automotive, aerospace and medical industries are only some of the sectors that machined components of high dimensional accuracy, exceptional properties, complex sizes and usually from difficult-to-machine materials, are employed.

The research in the refinement of machining or the introduction of new features is ongoing and fast-growing. Precision machining on large scale components but in the micro- and nano-regime as well, concentrate the interest of the researchers. In the success of the research there are other aspects that need to be considered as the machine tools design and control, cutting tools, metrology and quality control, manufacturing systems and automation and of course modeling and simulation with various methods such as finite elements method, molecular dynamics and soft computing.

This Special Issue aims at attracting researchers to present recent advances and technologies in the aforementioned fields and indicate the future trends for precision machining.

 Prof. Dr. Angelos P. Markopoulos

Guest Editor

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. Machines is an international peer-reviewed open access quarterly 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 350 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

  • Precision machining

  • Micro- and nano- machining

  • Machine tools

  • Abrasive processes

  • Non-conventional machining

  • Modeling and simulation

  • Surface quality and integrity

  • Manufacturing systems

  • Precision engineering

  • Nanomaterials

Published Papers (8 papers)

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Research

Open AccessArticle Influence of Hub Parameters on Joining Forces and Torque Transmission Output of Plastically-Joined Shaft-Hub-Connections with a Knurled Contact Surface
Machines 2018, 6(2), 16; doi:10.3390/machines6020016
Received: 27 February 2018 / Revised: 3 April 2018 / Accepted: 4 April 2018 / Published: 9 April 2018
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Abstract
A knurled interference fit is a machine part connection made by a plastic joining, which includes the advantages of commonly-used shaft-hub-connections. The combination of the friction and form fit, which are responsible for torque transmission, results in a higher power density than conventional
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A knurled interference fit is a machine part connection made by a plastic joining, which includes the advantages of commonly-used shaft-hub-connections. The combination of the friction and form fit, which are responsible for torque transmission, results in a higher power density than conventional connections. In this paper, parameter gaps are bridged with the aim of enhance the design calculation of the knurled interference fit. Experimental investigations on the shaft chamfer angle (100Cr6) and hub-diameter-ratio (AlSi1MgMn) were performed. The analytical approaches are developed for calculating the joining force and maximal torque capacity by accounting for experimentally investigated loss of load transmission at high hub-diameter-ratios and high shaft chamfer angles. The presented calculation approach is an accurate tool for the assessment of early machine designs of the knurled interference fit and helps to save from having to perform time-extensive tests. Full article
(This article belongs to the Special Issue Precision Machining)
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Open AccessArticle Theoretical and Experimental Studies of Over-Polishing of Silicon Carbide in Annular Polishing
Machines 2018, 6(2), 15; doi:10.3390/machines6020015
Received: 7 February 2018 / Revised: 28 March 2018 / Accepted: 3 April 2018 / Published: 4 April 2018
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Abstract
Annular polishing technology is an important optical machining method for achieving a high-precision mirror surface on silicon carbide. However, the inevitable over-polishing of the specimen edge in annular polishing deteriorates achieved surface quality. In the present work, we first analytically investigate the kinematic
[...] Read more.
Annular polishing technology is an important optical machining method for achieving a high-precision mirror surface on silicon carbide. However, the inevitable over-polishing of the specimen edge in annular polishing deteriorates achieved surface quality. In the present work, we first analytically investigate the kinematic coupling of multiple relative motions in the annular polishing process and subsequently derive an analytical model that addresses the principle of material removal at specimen edge based on the Preston equation and the rigid body contact model. We then perform finite element simulations and experiments involving annular polishing of silicon carbide (SiC), which jointly exhibit agreement with the derived analytical model of material removal. Full article
(This article belongs to the Special Issue Precision Machining)
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Open AccessArticle Effects of Setting Errors (Insert Run-Outs) on Surface Roughness in Face Milling When Using Circular Inserts
Machines 2018, 6(2), 14; doi:10.3390/machines6020014
Received: 6 March 2018 / Revised: 26 March 2018 / Accepted: 27 March 2018 / Published: 2 April 2018
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Abstract
In face milling, the roughness of the machined surface varies due to the movement of the cutting edge. Changes in roughness parameter values in the axis of rotation (symmetry plane) have been examined at a constant depth of cut for symmetrical milling. In
[...] Read more.
In face milling, the roughness of the machined surface varies due to the movement of the cutting edge. Changes in roughness parameter values in the axis of rotation (symmetry plane) have been examined at a constant depth of cut for symmetrical milling. In this paper, the effect of increasing feed per tooth on the topography of the surface is studied in fly-cutting and in multi-point face milling. The study takes into account the axial run-out of the inserts. Theoretical roughness values were modelled, the real values were tested in experiments and in both cases the impact of the run-out of the cutting edges and the change of the chip cross-section were also taken into account. Based on the performed experiments it can be stated that the accuracy of the introduced roughness prediction method increases with the increase in feed and therefore the application of the method in the case of high-feed milling is particularly effective. The results have also shown that the run-out of the insert significantly effects the roughness of the milled surfaces and therefore the measurement and minimization of these setting errors is essential. Full article
(This article belongs to the Special Issue Precision Machining)
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Open AccessArticle Comparative Analysis of Machining Procedures
Machines 2018, 6(2), 13; doi:10.3390/machines6020013
Received: 28 February 2018 / Revised: 21 March 2018 / Accepted: 22 March 2018 / Published: 28 March 2018
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Abstract
The in-depth analysis of cutting procedure is a topic of particular interest in manufacturing efficiency because in large-scale production the effective use of production capacities and the revenue-increasing capacity of production are key conditions of competitiveness. That is why the analysis of time
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The in-depth analysis of cutting procedure is a topic of particular interest in manufacturing efficiency because in large-scale production the effective use of production capacities and the revenue-increasing capacity of production are key conditions of competitiveness. That is why the analysis of time and material removal rate, which are in close relation to production, are important in planning a machining procedure. In the paper three procedures applied in hard cutting are compared on the basis of these parameters and a new parameter, the practical parameter of material removal rate, is introduced. It measures not only the efficiency of cutting but also that of the whole machining process because it includes the values measured by time analysis as well. In the investigations the material removal rate was analyzed, first on the basis of geometrical data of the component. After that different machining procedures (hard machining) were compared for some typical surfaces. The results can give some useful indications about machining procedure selection. Full article
(This article belongs to the Special Issue Precision Machining)
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Open AccessArticle Precision CNC Machining of Femoral Component of Knee Implant: A Case Study
Machines 2018, 6(1), 10; doi:10.3390/machines6010010
Received: 13 February 2018 / Revised: 27 February 2018 / Accepted: 28 February 2018 / Published: 2 March 2018
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Abstract
The design and manufacturing of medical implants constitutes an active and highly important field of research, both from a medical and an engineering point of view. From an engineering aspect, the machining of implants is undoubtedly challenging due to the complex shape of
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The design and manufacturing of medical implants constitutes an active and highly important field of research, both from a medical and an engineering point of view. From an engineering aspect, the machining of implants is undoubtedly challenging due to the complex shape of the implants and the associated restrictive geometrical and dimensional requirements. Furthermore, it is crucial to ensure that the surface integrity of the implant is not severely affected, in order for the implant to be durable and wear resistant. In the present work, the methodology of designing and machining the femoral component of total knee replacement using a 3-axis Computer Numerical Control (CNC) machine is presented, and then, the results of the machining process, as well as the evaluation of implant surface quality are discussed in detail. At first, a preliminary design of the components of the knee implant is performed and the planning for the production of the femoral component is implemented in Computed Aided Manufacturing (CAM) software. Then, three femoral components are machined under different process conditions and the surface quality is evaluated in terms of surface roughness. Analysis of the results indicated the appropriate process conditions for each part of the implant surface and led to the determination of optimum machining strategy for the finishing stage. Full article
(This article belongs to the Special Issue Precision Machining)
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Open AccessArticle The Dimensional Precision of Forming Windows in Bearing Cages
Machines 2018, 6(1), 9; doi:10.3390/machines6010009
Received: 5 February 2018 / Revised: 23 February 2018 / Accepted: 24 February 2018 / Published: 1 March 2018
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Abstract
In the case of double row tapered roller bearings, the windows found in bearing cages could be obtained using various machining methods. Some such machining methods are based on the cold forming process. There are many factors that are able to affect the
[...] Read more.
In the case of double row tapered roller bearings, the windows found in bearing cages could be obtained using various machining methods. Some such machining methods are based on the cold forming process. There are many factors that are able to affect the machining accuracy of the windows that exist in bearing cages. On the dimensional precision of windows, the clearance between punches and die, the work stroke length, and the workpiece thickness could exert influence. To evaluate this influence, experimental research was developed taking into consideration the height and the length of the cage window and the distance between the contact elements of the cage. By mathematical processing of the experimental results, empirical mathematical models were determined and analyzed. The empirical models highlighted the intensity of the influence exerted by the considered forming process input factors on the dimensional precision of the windows obtained in bearing cages. Full article
(This article belongs to the Special Issue Precision Machining)
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Open AccessArticle Numerical and Experimental Characterization of a Railroad Switch Machine
Machines 2018, 6(1), 6; doi:10.3390/machines6010006
Received: 15 January 2018 / Revised: 10 February 2018 / Accepted: 12 February 2018 / Published: 17 February 2018
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Abstract
This contribution deals with the numerical and experimental characterization of the structural behavior of a railroad switch machine. Railroad switch machines must meet a number of safety-related conditions such as, for instance, exhibiting the appropriate resistance against any undesired movements of the points
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This contribution deals with the numerical and experimental characterization of the structural behavior of a railroad switch machine. Railroad switch machines must meet a number of safety-related conditions such as, for instance, exhibiting the appropriate resistance against any undesired movements of the points due to the extreme forces exerted by a passing train. This occurrence can produce very high stress on the components, which has to be predicted by designers. In order to assist them in the development of new machines and in defining what the critical components are, FEA models have been built and stresses have been calculated on the internal components of the switch machine. The results have been validated by means of an ad-hoc designed experimental apparatus, now installed at the facilities of the Department of Industrial Engineering of the University of Bologna. This apparatus is particularly novel and original, as no Standards are available that provide recommendations for its design, and no previous studies have dealt with the development of similar rigs. Moreover, it has wide potential applications for lab tests aimed at assessing the safety of railroad switch machines and the fulfilment of the specifications by many railway companies. Full article
(This article belongs to the Special Issue Precision Machining)
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Open AccessArticle A Methodology for the Lightweight Design of Modern Transfer Machine Tools
Machines 2018, 6(1), 2; doi:10.3390/machines6010002
Received: 10 December 2017 / Revised: 7 January 2018 / Accepted: 11 January 2018 / Published: 14 January 2018
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Abstract
This paper deals with a modern design approach via finite elements in the definition of the main structural elements (rotary table and working unit) of an innovative family of transfer machine tools. Using the concepts of green design and manufacture, as well as
[...] Read more.
This paper deals with a modern design approach via finite elements in the definition of the main structural elements (rotary table and working unit) of an innovative family of transfer machine tools. Using the concepts of green design and manufacture, as well as sustainable development thinking, the paper highlights the advantages derived from their application in this specific field (i.e., the clever use of lightweight materials to allow ruling out high-consumption hydraulic pump systems). The design is conceived in a modular way, so that the final solution can cover transfers from four to 15 working stations. Two versions of the machines are examined. The first one has a rotary table with nine divisions, which can be considered as a prototype: this machine has been studied in order to set up the numerical predictive model, then validated by experimental tests. The second one, equipped with a rotary table with 15 divisions, is the biggest of the range: this machine has been entirely designed with the aid of the previously developed numerical model. The loading input forces for the analyses have been evaluated experimentally via drilling operations carried out on a three-axis CNC unit. The definition of the design force made it possible to accurately assess both the rotary table and the working units installed in the machine. Full article
(This article belongs to the Special Issue Precision Machining)
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