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Advances and Trends in Non-conventional, Abrasive and Precision Machining 2022
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Advances and Trends in Non-conventional, Abrasive and Precision Machining 2022

A special issue of Machines (ISSN 2075-1702). This special issue belongs to the section "Advanced Manufacturing".

Deadline for manuscript submissions: closed (15 January 2024) | Viewed by 12143

Special Issue Editors

Prof. Dr. Mariusz Deja

E-Mail Website
Guest Editor
Department of Manufacturing and Production Engineering, Faculty of Mechanical Engineering, Gdańsk University of Technology, 80-233 Gdańsk, Poland
Interests: adaptive and dynamic process planning; modelling and developing new tools for abrasive processes; design for additive manufacturing DFAM
Special Issues, Collections and Topics in MDPI journals
Dr. Angelos P. Markopoulos

E-Mail Website
Guest Editor
Section of Manufacturing Technology, School of Mechanical Engineering, National Technical University of Athens, 15780 Athens, Greece
Interests: manufacturing technology; machining processes; non-conventional machining; modeling and simulation
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The modern highly competitive industrial environment demands machining and production processes resulting in exceptional quality and precision. The general trend to design and manufacture more complicated mechanical components, along with the rapidly moving forward material science, raise the need to incorporate and develop new machining techniques in the manufacturing process. Nonconventional machining processes differ from conventional ones, as they utilize alternative types of energy, such as thermal, electrical, and chemical, to form or to remove material. Commonly, the energy source has high power density, while the process features prodigious accuracy, and the capability to produce and handle demanding shapes and geometries. Examples of nonconventional machining processes are electrical discharge machining (EDM), electrochemical machining (ECM), laser processing, and laser-assisted machining. Abrasive processes like grinding, lapping, polishing, and superfinishing are constantly developing and allow for obtaining a fine surface finish along with high efficiency.   

There is an increased scientific and commercial interest in in-depth understanding, and further development of the aforementioned nonconventional and precision machining processes. Research is moving forward through experimental studies, as well in the field of modeling and simulation, exploiting the increased available computational power. Multiphysics and multidisciplinary and multiscale modeling are powerful tools in the effort to optimize existing nonconventional precision machining processes, as well to develop novel ones. As their wider use by the industry swiftly grows, research has to be focused on them, not only due to the academic and scientific interest, but also for the possible financial gain.

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

Prof. Dr. Mariusz Deja
Dr. Angelos P. Markopoulos
Guest Editors

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 submissions that pass pre-check are 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 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 2400 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

  • laser processing/laser-assisted machining
  • high-density power machining
  • electrodischarge machining
  • electrochemical machining
  • abrasive processes
  • lapping/polishing/superfinishing
  • ultrasonic machining
  • water jet machining/abrasive water jet machining
  • burnishing
  • other nonconventional machining
  • precision machining
  • micro- and nanomachining
  • machine tools
  • modeling and simulation
  • surface quality and integrity
  • manufacturing systems
  • nanomaterials

Published Papers (11 papers)

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Research

16 pages, 6839 KiB  
Article
Research on Cutting Edge form Factor of Milling Tool after Drag Finishing Preparation Based on Discrete Element Method
by Lihong Zhou, Yongguo Wang and Dejin Lv
Machines 2024, 12(4), 236; https://doi.org/10.3390/machines12040236 - 04 Apr 2024
Viewed by 370
Abstract
Cutting edge preparation is a precision machining process that improves the surface quality of cutting tools through the relative movement of abrasives and the tool. Research on removing materials in drag finishing can be greatly beneficial to tool manufacturing. This paper proposes the [...] Read more.
Cutting edge preparation is a precision machining process that improves the surface quality of cutting tools through the relative movement of abrasives and the tool. Research on removing materials in drag finishing can be greatly beneficial to tool manufacturing. This paper proposes the hypothesis that both abrasive wear and erosion wear act on the surface of milling tools and discusses the material removal models for abrasive wear and erosion wear. The influence of immersion depth, abrasive velocity, abrasive radius, and abrasive density on the material removal rate in two material removal forms is compared and validated by discrete element simulations. The results show that immersion depth has a greater impact on abrasive wear, while abrasive properties have a greater impact on erosion wear. The correlation between simulation results and theoretical models demonstrates the sensitivity of the two forms of wear on this surface to parameter change differences. Dragging finishing was conducted to verify the effectiveness of the simulation, and the effects of immersion depth, dragging velocity, and abrasive properties on the edge radius and form factor (K value) were studied. Full article
(This article belongs to the Special Issue Advances and Trends in Non-conventional, Abrasive and Precision Machining 2022)
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15 pages, 11573 KiB  
Article
Image-Based Tool Characterization and DEM Simulation of Abrasive Brushing Processes
by Anton Hoyer and Eckart Uhlmann
Machines 2024, 12(3), 171; https://doi.org/10.3390/machines12030171 - 01 Mar 2024
Viewed by 1024
Abstract
Brushing with bonded abrasives is a finishing process used for deburring, edge rounding, and roughness reduction. However, due to the complex motion, chipping, and wear behavior of abrasive filaments, industrial brushing processes have historically relied on empirical knowledge. To gain a better understanding [...] Read more.
Brushing with bonded abrasives is a finishing process used for deburring, edge rounding, and roughness reduction. However, due to the complex motion, chipping, and wear behavior of abrasive filaments, industrial brushing processes have historically relied on empirical knowledge. To gain a better understanding of filament interactions, a physical model based on the discrete element method was developed to simulate process forces and contact areas. Filament patterns of round brushes were determined through the use of laser line triangulation and image processing. These filament patterns showed interlocked filaments and yielded more accurate results when used in brushing simulations than the oversimplified square patterns, which were used in previous research. Simulation confirms the occurrence of filament interactions, distinguishes between sweeping and striking filament motions, and reveals dynamic behavior at high brushing velocities that may increase undesirable tool wear. Full article
(This article belongs to the Special Issue Advances and Trends in Non-conventional, Abrasive and Precision Machining 2022)
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20 pages, 7105 KiB  
Article
A Comparative Study of Efficient Modeling Approaches for Performing Controlled-Depth Abrasive Waterjet Pocket Milling
by Nikolaos E. Karkalos and Panagiotis Karmiris-Obratański
Machines 2024, 12(3), 168; https://doi.org/10.3390/machines12030168 - 29 Feb 2024
Viewed by 813
Abstract
Non-conventional processes are considerably important for the machining of hard-to-cut alloys in various demanding applications. Given that the surface quality and integrity, dimensional accuracy, and productivity are important considerations in industrial practice, the prediction of the outcome of the material removal process should [...] Read more.
Non-conventional processes are considerably important for the machining of hard-to-cut alloys in various demanding applications. Given that the surface quality and integrity, dimensional accuracy, and productivity are important considerations in industrial practice, the prediction of the outcome of the material removal process should be able to be conducted with sufficient accuracy, taking into consideration the computational cost and difficulty of implementation of the relevant models. In the case of AWJ, various types of approaches have been already proposed, both relying on analytical or empirical models and developed by solving partial differential equations. As the creation of a model for AWJ pocket milling is rather demanding, given the number of parameters involved, in the present work, it is intended to compare the use of three different types of efficient modeling approaches for the prediction of the dimensions of pockets milled by AWJ technology. The models are developed and evaluated based on experimental results of AWJ pocket milling of a titanium workpiece by an eco-friendly walnut shell abrasive. The results indicate that a semi-empirical approach performs better than a two-step hybrid analytical/semi-empirical method regarding the selected cases, but both methods show promising results regarding the realistic representation of the pocket shape, which can be further improved by a probabilistic approach. Full article
(This article belongs to the Special Issue Advances and Trends in Non-conventional, Abrasive and Precision Machining 2022)
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13 pages, 2393 KiB  
Article
Implementation of Grey Wolf, Multi-Verse and Ant Lion Metaheuristic Algorithms for Optimizing Machinability of Dry CNC Turning of Annealed and Hardened UNIMAX® Tool Steel
by Nikolaos A. Fountas, Ioannis Papantoniou, Dimitrios E. Manolakos and Nikolaos M. Vaxevanidis
Machines 2024, 12(3), 156; https://doi.org/10.3390/machines12030156 - 24 Feb 2024
Cited by 1 | Viewed by 796
Abstract
Advances in machining technology and materials science impose the identification of optimal settings for process-related parameters to maintain high quality and process efficiency. Given the available resources, manufacturers should determine an advantageous process parameter range for their settings. In this work, the machinability [...] Read more.
Advances in machining technology and materials science impose the identification of optimal settings for process-related parameters to maintain high quality and process efficiency. Given the available resources, manufacturers should determine an advantageous process parameter range for their settings. In this work, the machinability of a special tool steel (UNIMAX® by Uddeholm, Sweden) under dry CNC turning is investigated. The working material is examined under two states; annealed and hardened. As major machinability indicators, main cutting force Fz (N) and mean surface roughness Ra (μm) were selected and studied under different values for the cutting conditions of cutting speed, feed rate, and depth of cut. A systematic experimental design was established as per the response surface methodology (RSM). The experimental design involved twenty base runs with eight cube points, four center points in the cube, six axial points, and two center points in the axial direction. Corresponding statistical analysis was based on analysis of variance and normal probability plots for residuals. Two regression models referring to main cutting force and surface roughness for both the annealed and hardened states of the material were developed and used as objective functions for subsequent evaluations by three modern meta-heuristics under the goal of machinability optimization, namely multi-objective grey wolf algorithm, multi-objective multi-verse algorithm and multi-objective ant lion algorithm. All algorithms were found capable of providing beneficial Pareto-optimal solutions for both main cutting force and surface roughness simultaneously whilst regression models achieved high correlation among input variables and optimization responses. Full article
(This article belongs to the Special Issue Advances and Trends in Non-conventional, Abrasive and Precision Machining 2022)
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20 pages, 5081 KiB  
Article
Investigation of Dynamic Behavior and Process Stability at Turning of Thin-Walled Tubular Workpieces Made of 42CrMo4 Steel Alloy
by Kamel Mehdi, Peter Pavol Monka, Katarina Monkova, Zied Sahraoui, Nawel Glaa and Jakub Kascak
Machines 2024, 12(2), 120; https://doi.org/10.3390/machines12020120 - 08 Feb 2024
Viewed by 863
Abstract
During machining, the surface of the machined materials is damaged and tool wear occurs, sometimes even to complete failure. Machining of thin-walled parts is generally cumbersome due to their low structural rigidity. The study deals with the effect of the feed rate and [...] Read more.
During machining, the surface of the machined materials is damaged and tool wear occurs, sometimes even to complete failure. Machining of thin-walled parts is generally cumbersome due to their low structural rigidity. The study deals with the effect of the feed rate and the thickness of the thin-walled part on the dynamic behavior and stability of the turning process during the roughing and finishing of thin-walled tubular workpieces made of steel alloy 42CrMo4. At the same time, the cutting forces and deformations of the workpiece were also evaluated via numerical and experimental approaches. The numerical study is based on a three-dimensional (3D) finite element model (FEM) developed using the ABAQUS/Explicit frame. In the model, the workpiece material is governed by the behavior law of Johnson–Cook. Numerical and experimental results show that the cutting forces and the quality of the machined surface depend not only on the choice of cutting parameters but also on the dynamic behavior of thin-walled parts due to their low rigidity and low structural damping during the machining operation. Cutting forces are proportional to the feed rate and inversely proportional to the thickness of the part. Their variations around the average values are low for roughing tests where the wall-part thickness is higher or equal to 3.5 mm. However, these variations intensify for finishing tests where the wall thickness is less or equal to 1.5 mm. Indeed, the recorded FFT spectra for a finishing operation show several harmonics that occurred at around 550 Hz, and the amplitude of the peaks, which describes the level of power contained in the signals, shows an increase similar to that of the amplitudes of the temporal signal. The flexibility of the part generates instability in the cutting process, but the frequencies of the vibrations are higher than the frequency of rotation of the part. Full article
(This article belongs to the Special Issue Advances and Trends in Non-conventional, Abrasive and Precision Machining 2022)
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15 pages, 7116 KiB  
Article
Analysis of Roughness, the Material Removal Rate, and the Acoustic Emission Signal Obtained in Flat Grinding Processes
by Piotr Sender, Irene Buj-Corral and Jesús Álvarez-Flórez
Machines 2024, 12(2), 110; https://doi.org/10.3390/machines12020110 - 06 Feb 2024
Viewed by 762
Abstract
In this work, the analysis of the acoustic emission (AE) signal in grinding processes is addressed. The proposed analysis method decomposes the acoustic signal into three frequency ranges. The total energy of each range is determined, as well as the highest frequency. Different [...] Read more.
In this work, the analysis of the acoustic emission (AE) signal in grinding processes is addressed. The proposed analysis method decomposes the acoustic signal into three frequency ranges. The total energy of each range is determined, as well as the highest frequency. Different grinding experiments were carried out, according to a full factorial design of experiments (DOE), in which feed speed, depth of cut, and transversal step (table cross feed) were varied. Arithmetic average roughness Ra and the material removal rate (MRR) were determined. It was observed that Ra depends mainly on the transversal step, followed by feed speed and the interaction between the transversal step and depth of cut, while MRR is greatly influenced by the transversal step. According to multi-objective optimization with the Derringer–Suich function, in order to simultaneously minimize Ra and maximize MRR, a transversal step of 9 mm per longitudinal pass, feed speed of 20 m/min, and depth of cut of 0.020 mm should be selected. Full article
(This article belongs to the Special Issue Advances and Trends in Non-conventional, Abrasive and Precision Machining 2022)
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17 pages, 4577 KiB  
Article
An Experimental and Numerical Study of the Laser Ablation of Bronze
by Esmaeil Ghadiri Zahrani, Vasiliki E. Alexopoulou, Emmanouil L. Papazoglou, Bahman Azarhoushang and Angelos Markopoulos
Machines 2024, 12(1), 63; https://doi.org/10.3390/machines12010063 - 16 Jan 2024
Viewed by 843
Abstract
The use of lasers in various precise material removal processes has emerged as a viable and efficient alternative to traditional mechanical methods. However, the laser ablation of materials is a complex, multi-parameter process where scanning paths need to be repeated multiple times. This [...] Read more.
The use of lasers in various precise material removal processes has emerged as a viable and efficient alternative to traditional mechanical methods. However, the laser ablation of materials is a complex, multi-parameter process where scanning paths need to be repeated multiple times. This repetition causes changes in the absorption and temperature distribution along the scanning path, thereby affecting the accuracy of the ablation. Therefore, it is crucial to thoroughly study these phenomena. This article presents an experimental and numerical study on the laser ablation of bronze (DIN: 1705) in a multi-track ablation process. Specifically, six consecutive passes using a ns laser at three different energy densities were conducted. After each pass, measurements of the ablation depth and pile-up height were taken at three distinct points along the track (start, middle, and end) to evaluate the efficiency and quality of the process. To gain a deeper understanding of the underlying physical mechanisms, a numerical simulation model based on the Finite Element Method (FEM) was developed. The effective absorptivity was defined through reverse engineering, and the material’s cooling rates were also estimated. This study’s findings provide significant insights into the influence of machining parameters on the ablation process and its progression with varying numbers of consecutive repetitions. A primarily linear correlation was deduced between the ablation depth, energy density, and number of repetitions, while the relationship with the pile-up height appeared to be more ambiguous and nonlinear. The estimated cooling rates ranged from 106 to 1010 [K/s]. Additionally, a heat accumulation phenomenon and a gradual temperature increase resulting from consecutive laser scans were also observed. A good agreement between the simulation results and experiments for the ablation depths was observed. Full article
(This article belongs to the Special Issue Advances and Trends in Non-conventional, Abrasive and Precision Machining 2022)
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15 pages, 7028 KiB  
Article
A New Slurry for Photocatalysis-Assisted Chemical Mechanical Polishing of Monocrystal Diamond
by Junyong Shao, Yanjun Zhao, Jianhui Zhu, Zewei Yuan, Haiyang Du and Quan Wen
Machines 2023, 11(6), 664; https://doi.org/10.3390/machines11060664 - 20 Jun 2023
Cited by 1 | Viewed by 1254
Abstract
Diamond needs to have a perfectly smooth surface due to the growing requirements in the fields of electronic semiconductors, optical windows and high-fidelity loudspeakers. However, the polishing of diamonds is highly challenging due to their exceptional hardness and chemical stability. In this study, [...] Read more.
Diamond needs to have a perfectly smooth surface due to the growing requirements in the fields of electronic semiconductors, optical windows and high-fidelity loudspeakers. However, the polishing of diamonds is highly challenging due to their exceptional hardness and chemical stability. In this study, a new polishing slurry is prepared for the proposed photocatalysis-assisted chemical mechanical polishing (PCMP) approach to obtain an ultra-smooth surface for large-area diamond. The analyses and experimental findings revealed the significance of the photocatalyst, abrasive, electron capture agent and pH regulator as essential components of the PCMP slurry. TiO2 with a 5 nm pore size and P25 TiO2 possess improved photocatalysis efficiency. Moreover, diamond removal is smooth under the acidic environment of H3PO4 due to the high oxidation–reduction potential (ORP) of the slurry, and, during the methyl orange test, P25 TiO2 exhibits reasonable photocatalytic effects. Moreover, in 8 h, a smooth surface free of mechanical scratches can be obtained by reducing the surface roughness from Ra 33.6 nm to Ra 2.6 nm. Full article
(This article belongs to the Special Issue Advances and Trends in Non-conventional, Abrasive and Precision Machining 2022)
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16 pages, 7640 KiB  
Article
Gear Wheel Finishing with Abrasive Brushing Tools to Improve the Surface Quality of Tooth Flanks for the Industrial Application
by Bernhard Gülzow and Eckart Uhlmann
Machines 2022, 10(12), 1220; https://doi.org/10.3390/machines10121220 - 15 Dec 2022
Cited by 2 | Viewed by 1604
Abstract
A high surface quality of tooth flanks can improve the service life and the performance of gears, as well as reduce acoustic emissions. However, high demands on the gear geometry pose a challenge for the finishing of tooth flank surfaces because the dimensional [...] Read more.
A high surface quality of tooth flanks can improve the service life and the performance of gears, as well as reduce acoustic emissions. However, high demands on the gear geometry pose a challenge for the finishing of tooth flank surfaces because the dimensional accuracy that can be achieved with modern grinding processes must not be impaired by the finishing process. A preceding study has shown fundamentally that profiled abrasive brushing tools can be used to improve the quality of individual tooth flank surfaces. Due to the integration into the grinding machine, it represents a promising alternative to common finishing applications. Before the process can be used in an industrial environment, process reliability and tool life must be examined. For this purpose, complete reference gearwheels (39 × 10) were finished with the brushing tools. It could be shown that the surface roughness can be reliably reduced by ΔRa ≈ 0.2 µm by using a single brush for an entire gearwheel without changing the gear geometry. In addition to the influence of the tool specifications on the work result, the influence of the initial roughness after grinding was considered in particular. It was found that the achievable surface roughness depends significantly on the depth of the grinding grooves, as these are retained as desired, while the roughness peaks are fully smoothed. Furthermore, a device for the machine-integrated profiling and dressing of brushing tools was successfully designed, implemented, and tested. Full article
(This article belongs to the Special Issue Advances and Trends in Non-conventional, Abrasive and Precision Machining 2022)
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17 pages, 4910 KiB  
Article
Prediction of the Roughness Reduction in Centrifugal Disc Finishing of Additive Manufactured Parts Based on Discrete Element Method
by Marco Kopp and Eckart Uhlmann
Machines 2022, 10(12), 1151; https://doi.org/10.3390/machines10121151 - 01 Dec 2022
Cited by 4 | Viewed by 1321
Abstract
One major drawback of additive manufacturing is the poor surface quality of parts, which negatively affects mechanical and tribological properties. Therefore, a surface finishing is necessary in most cases. Due to a high material removal rate, centrifugal disc finishing is a promising mass [...] Read more.
One major drawback of additive manufacturing is the poor surface quality of parts, which negatively affects mechanical and tribological properties. Therefore, a surface finishing is necessary in most cases. Due to a high material removal rate, centrifugal disc finishing is a promising mass finishing operation for an effective surface finishing of additive manufactured parts. However, due to machining the workpieces in a freely movable manner, the process is hardly controllable, and the process design is often based on time-consuming and cost-intensive trial-and-error approaches. Especially when it comes to the machining of complex-shaped workpieces, finishing results are barely predictable. Therefore, the aim of this study is to set up a numerical simulation of the centrifugal disc finishing based on the Discrete Element Method (DEM) to predict finishing results. A procedure to determine the required DEM input parameters is presented and the simulation was validated using a freely movable force sensor. The results of the finishing experiments with additive manufactured workpieces made of Ti-6Al-4V were correlated with the simulated results. The derived correlation was used to predict local differences in the roughness reduction, which occurred when finishing workpieces with a limited accessibility to the surface. As a result, it is concluded that the complex relationship between the type of media, the accessibility to the surface, and the achievable finishing results can be modeled using the DEM. Full article
(This article belongs to the Special Issue Advances and Trends in Non-conventional, Abrasive and Precision Machining 2022)
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14 pages, 1801 KiB  
Communication
Theoretical Assessment of the Role of Bond Material during Grinding of Superhard Materials with Diamond Wheels
by János Kundrák, Vladimir Fedorovich, Angelos P. Markopoulos, Ivan Pyzhov and Yevgeniy Ostroverkh
Machines 2022, 10(7), 543; https://doi.org/10.3390/machines10070543 - 05 Jul 2022
Cited by 2 | Viewed by 1541
Abstract
The grinding of superhard materials poses an important challenge to manufacturing industry, due to the increased wear and the high possibility of fracture of both the wheel and workpiece material. Various strategies have been proposed for effective grinding of these materials, but further [...] Read more.
The grinding of superhard materials poses an important challenge to manufacturing industry, due to the increased wear and the high possibility of fracture of both the wheel and workpiece material. Various strategies have been proposed for effective grinding of these materials, but further research is still required, especially in cases in which the hardness of the wheel and the workpiece are almost equal. In this study, the role of the bond of a diamond grinding wheel during the processing of superhard materials, such as synthetic diamond, is investigated using theoretical models and FE simulation. Six different types of bonds are studied and the effect of their properties on the stress distribution of workpiece material is determined. Results indicate that even a slight increase in elastic modulus can affect considerably the stress state of the workpiece, directly affecting the critical embedding value of grains into the bond, something that can alter considerably the efficiency of grinding superhard materials. Thus, grinding wheels with bonds of high elastic modulus should be selected in order to increase grain retention, increase processing efficiency, and reduce specific consumption even at higher cross feeds and wheel speeds. Full article
(This article belongs to the Special Issue Advances and Trends in Non-conventional, Abrasive and Precision Machining 2022)
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