for Journals by Title or ISSN
for Articles by Keywords
help
  Subjects -> MANUFACTURING AND TECHNOLOGY (Total: 297 journals)
    - CERAMICS, GLASS AND POTTERY (26 journals)
    - MACHINERY (33 journals)
    - MANUFACTURING AND TECHNOLOGY (184 journals)
    - METROLOGY AND STANDARDIZATION (4 journals)
    - PACKAGING (15 journals)
    - PAINTS AND PROTECTIVE COATINGS (5 journals)
    - PLASTICS (28 journals)
    - RUBBER (2 journals)

MACHINERY (33 journals)

Showing 1 - 33 of 33 Journals sorted alphabetically
Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9)
Advanced Energy Materials     Hybrid Journal   (Followers: 24)
Applied Mechanics Reviews     Full-text available via subscription   (Followers: 26)
BER : Consumer Goods Industries Survey     Full-text available via subscription  
BER : Intermediate Goods Industries Survey     Full-text available via subscription   (Followers: 1)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
CORROSION     Full-text available via subscription   (Followers: 20)
Electric Power Components and Systems     Hybrid Journal   (Followers: 7)
Engenharia Agrícola     Open Access  
Foundations and Trends® in Electronic Design Automation     Full-text available via subscription  
High Speed Machining     Open Access   (Followers: 4)
High Temperature Materials and Processes     Hybrid Journal   (Followers: 5)
International Journal of Machine Tools and Manufacture     Hybrid Journal   (Followers: 7)
International Journal of Machining and Machinability of Materials     Hybrid Journal   (Followers: 6)
International Journal of Manufacturing Technology and Management     Hybrid Journal   (Followers: 8)
International Journal of Precision Technology     Hybrid Journal  
International Journal of Rapid Manufacturing     Hybrid Journal   (Followers: 4)
International Journal of Rotating Machinery     Open Access   (Followers: 2)
Journal of Machinery Manufacture and Reliability     Hybrid Journal   (Followers: 2)
Journal of Machinery Manufacturing and Automation     Open Access   (Followers: 2)
Journal of Modeling in Mechanics and Materials     Partially Free  
Journal of Strain Analysis for Engineering Design     Hybrid Journal   (Followers: 6)
Journal of Terramechanics     Hybrid Journal   (Followers: 5)
Machine Design     Partially Free   (Followers: 106)
Machines     Open Access   (Followers: 2)
Materials     Open Access   (Followers: 7)
Mechanics Based Design of Structures and Machines: An International Journal     Hybrid Journal   (Followers: 4)
Micromachines     Open Access   (Followers: 3)
Practical Machinery Management for Process Plants     Full-text available via subscription  
Pump Industry Analyst     Full-text available via subscription   (Followers: 2)
Russian Engineering Research     Hybrid Journal  
Sensor Review     Hybrid Journal   (Followers: 2)
Surface Engineering and Applied Electrochemistry     Hybrid Journal   (Followers: 5)
Journal Cover International Journal of Machine Tools and Manufacture
  [SJR: 2.746]   [H-I: 100]   [7 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0890-6955
   Published by Elsevier Homepage  [3031 journals]
  • Error Calibration of Controlled Rotary Pairs in Five-axis Machining
           Centers Based on the Mechanism Model and Kinematic Invariants
    • Authors: Zhi Wang; Delun Wang; Yu Wu; Huimin Dong; Shudong Yu
      Pages: 1 - 11
      Abstract: Publication date: Available online 20 April 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhi Wang, Delun Wang, Yu Wu, Huimin Dong, Yu Shudong
      The mechanism model of ball bar testing for a two-axis rotary table of 5-axis machining center is discussed, and a new ball bar method to measure the three-dimensional motions of the rotary pairs in multi-axis machining center is developed based on the mechanism model. Then, the fixed axes and moving axes of the rotary pairs are identified by using spherical image circle fitting and striction circle fitting, according to the kinematic invariants of nominal rotation and the measured motions. The structure errors and kinematic pair errors of the rotary pairs are defined and identified by using the fixed and moving axes, and the kinematic model of the two-axis rotary table is deduced with those errors. The simultaneous two-axis motions of the rotary table are measured to verify the proposed calibration method. The experimental results show good agreements with the predicted results calculated by the calibrated kinematic model. Furthermore, the accuracy of the simultaneous multi-axis motions of the machining center is improved when the identified errors are corrected.

      PubDate: 2017-04-24T12:15:52Z
      DOI: 10.1016/j.ijmachtools.2017.04.011
      Issue No: Vol. 120 (2017)
       
  • A systematic approach on analyzing the relationship between straightness
           & angular errors and guideway surface in precise linear stage
    • Authors: Hao Tang; Ji-an Duan; Qiancheng Zhao
      Pages: 12 - 19
      Abstract: Publication date: Available online 19 April 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Hao Tang, Ji-an Duan, Qiancheng Zhao
      In this paper, a systematic approach on how to calculate the straightness and angular errors based on measuring guideway surface and fitting curve is introduced. Straightness and angular errors play an important role in precise system, which can undermine the system accuracy, especially in multi-axis motion structure. Conventional method adopts a periodic function to represent the guideway surface. However, for majority environments, the guideway surface curve is random depending on different machining processes. Thus, it is necessary to develop a precise method to obtain the guideway surface curve for calculating the straightness & angular errors. Instead of adopting trigonometric function to represent the guideway surface, this paper measures the guideway first. By analyzing the characteristics of machining process for guide rail, the proper characteristic functions are selected in curve fitting based on the measurement results, and an accurate analytical expression of guideway surface is obtained. Therefore, the SaA error values can be calculated with corresponding formulas based on the expression. Compared with previous method, the new approach is more accurate in curve fitting and error calculation, which can be applied in other similar environment through the same procedure. Furthermore, by analyzing the measured results of guideway surface, the new approach procedure can be regarded as a bridge between the pattern of measured guideway surface and corresponding manufacture process, which is seldom discussed in other research works. This new approach is also comprehensive and systematic in error analysis in precise linear stages, which is beneficial to derive the distribution of straightness and angular errors for engineers before installation in design part. A case study of a precise linear stage by following the procedure in the new approach is developed, and the comparison between calculation and measured results proves the validation of the new approach.

      PubDate: 2017-04-24T12:15:52Z
      DOI: 10.1016/j.ijmachtools.2017.04.010
      Issue No: Vol. 120 (2017)
       
  • Orthogonal cutting of cortical bone: Temperature elevation and fracture
           toughness
    • Authors: Arne Feldmann; Philipp Ganser; Lutz Nolte; Philippe Zysset
      Pages: 1 - 11
      Abstract: Publication date: August 2017
      Source:International Journal of Machine Tools and Manufacture, Volumes 118–119
      Author(s): Arne Feldmann, Philipp Ganser, Lutz Nolte, Philippe Zysset
      During surgical procedures, the heat development of bone cutting can lead to thermal cell necrosis and secondary implant instability. Therefore, fundamental knowledge on heat development and temperature control is crucial. This paper investigates the basic principles of the machining of cortical bone in an orthogonal cutting process. Cutting forces, temperature elevation and chip formation were measured in real time for two different rake angles and six different cutting depths. A non-linear relationship between cutting depth and cutting forces as well as temperature elevation was found. The cutting behavior changed from a ductile to two distinguishable fracture cutting modes with increasing cutting depth. A linear correlation between cutting forces and temperature elevation of both bone chip and workpiece was determined ( R 2 = 0.8697 ). An increasing rake angle lowered cutting forces and temperature elevations significantly and was explained using a fracture mechanics approach. Additionally, a new method to calculate the fracture toughness of (quasi-)brittle materials from orthogonal cutting tests was introduced.

      PubDate: 2017-04-10T11:54:27Z
      DOI: 10.1016/j.ijmachtools.2017.03.009
      Issue No: Vol. 118-119 (2017)
       
  • Laser powder bed fusion of Ti-6Al-4V parts: Thermal modeling and
           mechanical implications
    • Authors: Mohammad Masoomi; Scott M. Thompson; Nima Shamsaei
      Pages: 73 - 90
      Abstract: Publication date: Available online 14 April 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Mohammad Masoomi, Scott M. Thompson, Nima Shamsaei
      A continuum-scale modeling approach is developed and employed with three-dimensional finite element analysis (FEA), for simulating the temperature response of a Ti-6Al-4V, two-layered parallelepiped with dimensions of 10 × 5 x 0.06 mm3 during Laser Powder Bed Fusion (L-PBF), a metals additive manufacturing (AM) method. The model has been validated using experimental melt pool measurements from the literature and also accounts for latent heat of fusion and effective, temperature-dependent transport properties. The discretized temperature, temperature time rate of change (i.e. cooling rate) and temperature gradient are investigated for various scan strategies and number of lasers, i.e. 1, 2 or 4. The thermal response inherent to multi-laser PBF (ML-PBF) is investigated. The number of sub-regional areas of the powder bed dedicated to individual lasers, or ‘islands’, was varied. The average, maximum cooling rate and temperature gradient per layer, as well as the spatial standard deviation, or uniformity, of such metrics, are presented and their implications on microstructure characteristics and mechanical traits of Ti-6Al-4V are discussed. Results demonstrate that increasing the number of lasers will reduce production times, as well as local cooling rates and residual stress magnitudes; however, the anisotropy of the residual stress field and microstructure may increase based on the scan strategy employed. In general, scan strategies that employ reduced track lengths oriented parallel to the part's shortest edge, with islands ‘stacked’ in a unit-row, proved to be most beneficial for L-PBF.

      PubDate: 2017-04-17T15:21:39Z
      DOI: 10.1016/j.ijmachtools.2017.04.007
      Issue No: Vol. 118-119 (2017)
       
  • Servo performance improvement through iterative tuning feedforward
           controller with disturbance compensator
    • Authors: Jianhua Wu; Yong Han; Zhenhua Xiong; Han Ding
      Pages: 1 - 10
      Abstract: Publication date: June 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 117
      Author(s): Jianhua Wu, Yong Han, Zhenhua Xiong, Han Ding
      Servo system is widely used in NC machines and its performance directly determines the precision of the machines. In most situations, the control structure for the servo system usually contains a cascaded P-PI feedback controller and a feedforward controller. This paper focuses on the feedforward controller parameters tuning to improve the servo performance. The feedforward controller consists of a model inversion and a parameterized disturbance model. Its parameters are tuned iteratively using the last cycle motion results. This method has the good extrapolation capability to the references and the performance improvement capacity. Moreover, it is easy to implement in real machines due to the simplicity and thus is of interest to control engineers. Experiments are carried out on an industrial prototype system. The results show that the proposed tuning method can improve the servo performance rapidly and the references are not required to keep the same during the tuning process.

      PubDate: 2017-02-16T05:03:14Z
      DOI: 10.1016/j.ijmachtools.2017.02.002
      Issue No: Vol. 117 (2017)
       
  • Direct Fabrication of Unsupported Inclined Aluminum Pillars based on
           Uniform Micro Droplets Deposition
    • Authors: Daicong Zhang; Lehua Qi; Jun Luo; Hao Yi; Xianghui Hou
      Pages: 18 - 24
      Abstract: Publication date: Available online 3 January 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Daicong Zhang, Lehua Qi, Jun Luo, Hao Yi, Xianghui Hou
      In order to investigate forming directly complex parts without support materials or structures by uniform micro droplets deposition technique, the present work focus on fabricating the unsupported inclined aluminum pillars through offset deposition. An experimental system is developed to produce and deposit uniform molten aluminum droplets. A model is introduced to describe the inclined angle of the droplet deposition at different offset ratios. A one dimensional heat transfer model is proposed to help select the initial temperature parameters of the impinging droplet and the previous solidified droplet to ensure that the fusion occurs. No melting, partial melting and excessive melting region at different offset ratios are determined. The correspondence between offset ratio and inclined angle is considered to be a simple cosine function, and the hypothesis is verified by experiments. The influence of deposition error on an inclined angle of pillars is studied. Internal microstructure of droplet fusion is observed in order to ensure good metallurgical bonding. All of these studies show the feasibility of fabricating directly unsupported inclined aluminum pillars in the limited angle range by using uniform micro droplets.

      PubDate: 2017-01-06T10:07:38Z
      DOI: 10.1016/j.ijmachtools.2017.01.001
      Issue No: Vol. 116 (2017)
       
  • Theoretical and experimental investigation of spindle axial drift and its
           effect on surface topography in ultra-precision diamond turning
    • Authors: Quanhui Wu; Yazhou Sun; Wanqun Chen; Guoda Chen
      Pages: 107 - 113
      Abstract: Publication date: May 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 116
      Author(s): Quanhui Wu, Yazhou Sun, Wanqun Chen, Guoda Chen
      In ultra-precision diamond turning (UPDT), the spindle axial drift directly affects the machining accuracy. Due to the difficulty of measuring the spindle drift during the machining process, the spindle axial drift was rarely studied. In this paper, an experimental method is used to prove and measure the existence of the spindle axial drift at the machining process, and the influence of spindle drift error on the machined surface is further studied. A mechanical model of the spindle system is considering the mass eccentricity, and the dynamic behavior of the spindle in working conditions are simulated with the mathematical model. Periodicity whirl of the spindle is found in the simulation, which is verified by the end face turning experiments. Then, the influence of the spindle vibration on surface topography is discussed, considering the spindle rotation speed and its dynamic balance. Meanwhile, the vibration frequencies induced by the spindle rotation are detected by the signal analyzer, and the detected frequency has been found to agree well with the experimental wave period of the workpiece surface (WS). This study is quite meaningful for deeply understanding the influence rule of spindle unbalanced error from the viewpoint of machined surface and vibration frequency. The research results are useful for the spindle error control and machined surface error prediction.

      PubDate: 2017-02-10T13:07:40Z
      DOI: 10.1016/j.ijmachtools.2017.01.006
      Issue No: Vol. 116 (2017)
       
  • Special issue on far east innovations in super-fine machining
    • Authors: Anthony T. Beaucamp; Dragos Axinte
      First page: 1
      Abstract: Publication date: April 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 115
      Author(s): Anthony T. Beaucamp, Dragos Axinte


      PubDate: 2017-03-02T11:26:59Z
      DOI: 10.1016/j.ijmachtools.2017.02.001
      Issue No: Vol. 115 (2017)
       
  • Prediction of surface roughness in abrasive waterjet trimming of fiber
           reinforced polymer composites
    • Authors: J. Schwartzentruber; J.K. Spelt; M. Papini
      Abstract: Publication date: Available online 25 May 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): J. Schwartzentruber, J.K. Spelt, M. Papini
      Surface roughness is a valuable metric when assessing abrasive waterjet machining (AWJM) cut quality. This paper presents 2D and 3D models capable of predicting the surface roughness during abrasive waterjet (AWJ) trimming of composite substrates. The composites used were a carbon-fiber laminate with an epoxy resin and a random oriented carbon-fiber/vinyl ester. The models were based on an earlier rigid-plastic erosive particle indentation model capable of predicting crater sizes using the particle impact and substrate properties. In the 2D model, single particle impact craters were aligned to form multi-particle impact profiles that were iteratively superimposed until a steady-state surface roughness was achieved. The 3D model generated conical craters that were individually superimposed until a steady-state surface roughness was achieved. The models were capable of predicting the surface roughness with an average error of 10% and 16%, for the 2D and 3D models, respectively. The models show that the surface roughness decreased with an increase in particle velocity, a decrease in kerf taper, and an increase in the dynamic hardness of the target.

      PubDate: 2017-05-27T08:40:38Z
      DOI: 10.1016/j.ijmachtools.2017.05.007
       
  • Corrigendum to “Theoretical and experimental investigation of spindle
           axial drift and its effect on surface topography in ultra-precision
           diamond turning” [International Journal of Machine Tools &
           Manufacture 116 (2017) 107–113]
    • Authors: Quanhui Wu; Yazhou Sun; Wanqun Chen; Guoda Chen
      Abstract: Publication date: Available online 23 May 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Quanhui Wu, Yazhou Sun, Wanqun Chen, Guoda Chen


      PubDate: 2017-05-27T08:40:38Z
      DOI: 10.1016/j.ijmachtools.2017.05.003
       
  • IFC - Editorial board
    • Abstract: Publication date: August 2017
      Source:International Journal of Machine Tools and Manufacture, Volumes 118–119


      PubDate: 2017-05-12T05:30:51Z
       
  • A REVIEW OF HELICAL MILLING PROCESS
    • Authors: Robson Bruno Dutra Pereira; Lincoln Cardoso Brandão; Anderson Paulo de Paiva; João Roberto Ferreira; J. Paulo Davim
      Abstract: Publication date: Available online 9 May 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Robson Bruno Dutra Pereira, Lincoln Cardoso Brandão, Anderson Paulo de Paiva, João Roberto Ferreira, J. Paulo Davim
      Helical milling is an alternative hole-making machining process which presents several advantages when compared to conventional drilling. In the helical milling process, the tool proceeds a helical path while rotates around its own axis. Due to its flexible kinematics, low cutting forces, tool wear, and improved borehole quality may be achieved. This paper presents a review of the helical milling process. As a first paper aiming to describe the current state of the art of helical milling process, the recent works about this process were summarized to point out the future trends in this field. Initially, the advantages of the helical milling were presented with regard to conventional drilling. Subsequently, the kinematics of the process was presented to standardize the nomenclature and to provide knowledge about the movements and parameters of helical milling. It was demonstrated the feed velocity decomposition in frontal and peripheral directions. Undeformed chip and cutting volumes of frontal and peripheral cut were described, and the ratio between the cutting volumes removed by frontal and peripheral cut was demonstrated to be dependent only of the borehole and tool diameters. Cutting forces and temperature studies were also summarized, corroborating that the helical milling is a smooth hole-making process. Afterward, tool life and wear studies in helical milling were summarized, testifying that the tool wear evolution can be monitored in frontal and peripheral cutting edges, with frontal cutting edges, in most cases, defining the tool life. Some statistical and soft computing applications on helical milling were also mentioned. To provide initial guidelines for applying helical milling, a screening of the current literature was performed summarizing equipment and cooling techniques used, and the levels of cutting conditions of helical milling applied for hole-making different materials. The quality of boreholes obtained by helical milling was assessed in terms of dimensional, geometrical, and microgeometrical deviations, besides burr and delamination levels, assuring that it can be obtained finished boreholes with helical milling. In the conclusions, future possibilities on research about helical milling were pointed out. This general review of helical milling may be referenced as a summary of the current results obtained in experimental and theoretical studies and to provide future research needs and opportunities.

      PubDate: 2017-05-12T05:30:51Z
      DOI: 10.1016/j.ijmachtools.2017.05.002
       
  • Experimental and Modeling Characterization of Wear and Life Expectancy of
           Electroplated CBN Grinding Wheels
    • Authors: Tianyu Yu; Ashraf F. Bastawros; Abhijit Chandra
      Abstract: Publication date: Available online 3 May 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Tianyu Yu, Ashraf F. Bastawros, Abhijit Chandra
      Wear and life expectancy of a nickel-electroplated monolayer of cubic boron nitride grinding wheels are characterized based on the wheel surface topological evolution, observed after grinding Inconel 718 super-alloys. The wheel is for surface or cylindrical grinding, and having 250 mm diameter, 10mm thickness and B40/50 coarse grit size. A unique grit-workpiece interaction process, leading to a non-uniform spatial distribution of the grit wear has been identified. Largest grits have been observed to pullout rapidly, resulting in load redistribution to their surroundings, and leading to the attritious and fracture wear phase. The detailed analysis showed that the stresses on the cutting grits arising from the thermal shock are 3–5 folds those arising from mechanical cutting forces, and reach an order of magnitude differences for the high efficiency deep grinding (HEDG) process. It is also found that the grit wear rate is primarily dependent on the workpiece feed rate rather than the grinding wheel speed. The total wheel life is then constructed as the sum of pullout life (Phase-I) and attritious and fracture wear life (Phase-II). Model predictions for the total wheel life compare well to the experimental observations. This facilitates comparisons of different types of grinding configurations and design space exploration. As an example, the HEDG process is compared to a regular high speed grinding, and it is observed that HEDG configuration can deliver much higher material removal for the same amount of wheel wear.

      PubDate: 2017-05-07T05:23:47Z
      DOI: 10.1016/j.ijmachtools.2017.04.013
       
  • Chemical-mechanical wear of monocrystalline silicon by a single pad
           asperity
    • Authors: Lin Wang; Ping Zhou; Ying Yan; Bi Zhang; Renke Kang; Dongming Guo
      Abstract: Publication date: Available online 3 May 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Lin Wang, Ping Zhou, Ying Yan, Bi Zhang, Renke Kang, Dongming Guo
      Chemical mechanical polishing (CMP) processes have been widely used in many fields with the ability to obtain an ultra-smooth surface. However, a comprehensive understanding of the material removal mechanisms at single pad asperity scale is still lacking, where a large number of abrasive particles are entrapped in the pad asperity/wafer microcontact area and then participate into polishing. In this study, two different pad asperity-scale material removal models are derived based on the indentation-sliding mechanism and chemical bond removal mechanism, respectively. Furthermore, series of pad asperity scale polishing tests are conducted on monocrystalline silicon wafer surface by using a polyoxymethylene (Pom) ball to mimic a single pad asperity. The results show that under the asperity-scale, material removal is highly related to the chemical reaction time between sequential asperity-wafer interactions, indicating the chemical control of the removal rate by controlling the reacted layer thickness. In particular, it is found that the reacted layer thickness follows the diffusion equation, and atoms within not only the topmost surface layer, but also the next or deeper layer can participate in the chemical reaction. Material removal behavior can be well explained by the dynamic formation and breakage of the interfacial chemical bonds between the Si atoms and SiO2 particles, rather than the indentation-sliding mechanism. It is further confirmed that no damage, such as lattice distortion or dislocation, is found in the subsurface of a wafer by the high-resolution transmission electron microscopy (HRTEM). This study provides new insights into the material removal mechanisms in CMP at an asperity-scale.

      PubDate: 2017-05-07T05:23:47Z
      DOI: 10.1016/j.ijmachtools.2017.05.001
       
  • Analysis of Grit Interference Mechanisms for the Double Scratching of
           Monocrystalline Silicon Carbide by Coupling the FEM and SPH
    • Authors: Nian Duan; Yiqing Yu; Wenshan Wang; Xipeng Xu
      Abstract: Publication date: Available online 27 April 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Nian Duan, Yiqing Yu, Wenshan Wang, Xipeng Xu
      Three-dimensional twice scratching and double scratching of monocrystalline silicon carbide with two cone-shaped grains were simulated by coupling the finite element (FEM) and smoothed particle hydrodynamics (SPH) to resolve the mesh distortion problem caused by using the FEM. Twice-scratching experiments were performed under three different conditions to validate the coupled finite element (FE) and SPH model in the scratching simulation with two diamond grits. The experimental results were compared to the simulation results. For twice scratching, the simulation results conform with the experimental results, indicating the validity of the coupled FE and SPH model. Thus, the coupled FE and SPH model was used to simulate the double-scratching process under different conditions. The results of the double-scratching simulation showed that the interference damages in the scratching process occurred under three circumstances: the interference of lateral cracks, the interference of lateral cracks and plastic damage, and the interference of plastic damage. The influence of distance on the interference damage of the two diamond grits in the Y-direction was analysed. The changes in the maximum depth and width in the interference region and the scratching force with the distance of the two grains in the Y-direction are illustrated.

      PubDate: 2017-05-01T01:22:15Z
      DOI: 10.1016/j.ijmachtools.2017.04.012
       
  • A fundamental investigation on ultrasonic vibration-assisted laser
           engineered net shaping of stainless steel
    • Authors: Weilong Cong; Fuda Ning
      Abstract: Publication date: Available online 21 April 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Weilong Cong, Fuda Ning
      Laser engineered net shaping (LENS), a laser beam deposition additive manufacturing method, has been utilized as a key technology in the direct manufacturing or repairing of metal parts. However, deposition defects such as pores, cavity, micro-cracks, residual stress, and uncertain microstructures always exist in the LENS fabricated parts, which will greatly affect the qualities and mechanical properties. In this paper, a novel ultrasonic vibration-assisted (UV-A) LENS process is proposed to reduce or eliminate the common defects due to the nonlinear actions and influences of ultrasonic vibration in molten materials. An experimental investigation is conducted on the effects of ultrasonic vibration on fabricated part geometry, powder utilization efficiency, surface roughness, geometry of molten pool and dilution zone, pores and micro-cracks, and grain size of the LENS-deposited AISI 630 stainless steel. The mechanical properties including tensile properties and hardness of the fabricated parts are evaluated and compared between UV-A LENS and LENS without ultrasonic vibration. The results show that process with ultrasonic vibration led to higher powder utilization efficiency, smaller flatness and surface roughness, and larger molten pool dimensions. Pores and micro-cracks were successfully reduced and crystal grains were significantly refined in UV-A LENS process. The improvement of these geometrical and microstructural characteristics induced by ultrasonic vibration further led to the increase in both tensile properties and hardness of LENS fabricated parts. The fundamental investigation in this work will help to establish an efficient and effective process for additive manufacturing and remanufacturing of metal parts with significantly improved qualities.

      PubDate: 2017-04-24T12:15:52Z
      DOI: 10.1016/j.ijmachtools.2017.04.008
       
  • Investigation on hybrid micro-texture fabrication in elliptical
           vibration-assisted cutting
    • Authors: Chen Zhang; Guilin Shi; Kornel F. Ehmann
      Abstract: Publication date: Available online 21 April 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Chen Zhang, Guilin Shi, Kornel F. Ehmann
      Various micro-texturing methods have been used to control surface topography. However, most of the available methods are inherently difficult to adopt for the efficient generation of intricate micro-textures on cylindrical surfaces. In this paper, a novel ultrasonic elliptical vibration-assisted cutting technique based on a micro-texturing model is proposed to fabricate hybrid micro-textures with different geometric characteristics. In the proposed elliptical vibration-assisted hybrid micro-texturing method an intricately shaped primary micro-texture is generated by elliptical vibration-assisted cutting, while the desired secondary textures are simultaneously constructed through a controlled intersection with neighboring elliptical vibration-assisted cutting loci. The cutting loci for the fabrication of the hybrid micro-textures is mathematically calculated according to a geometric model of hybrid micro-texturing. The topography of the hybrid dimples is analyzed to verify the correctness of the cutting locus generation method. Locus compensation methods, considering the elliptical vibration locus and the tool nose radius are proposed to reduce fabrication errors during the hybrid dimple generation process. Micro-scale hybrid dimples, which are in close compliance with the results of the mathematical calculations, were successfully fabricated on machined cylindrical surfaces. The comparison of the results shows that the proposed method is satisfactory and can be used to predict and generate hybrid micro-textures on cylindrical surfaces.

      PubDate: 2017-04-24T12:15:52Z
      DOI: 10.1016/j.ijmachtools.2017.04.009
       
  • Process Development Toward Full-Density Stainless Steel Parts with Binder
           Jetting Printing
    • Authors: Truong Do; Patrick Kwon; Chang Seop Shin
      Abstract: Publication date: Available online 14 April 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Truong Do, Patrick Kwon, Chang Seop Shin
      In the Additive Manufacturing (AM) community, the binder jet printing (BJP) process is known to produce parts not suitable for most structural applications due to the insufficient consolidation of the powder in the finished part. A new processing protocol for the BJP is presented to reach near full density and better surface finish for stainless steel (SS) parts. Two main modifications from the standard BJP processing are (1) the use of the mixtures of various powders and (2) the adaptation of a full sintering cycle in a vacuum furnace. Two distinct average particle sizes of SS powder were used to improve the packing density in the printing stage. Improving the packing density of the printed powder helps to consolidate the powder better and to reduce the shape distortion in the final parts. More importantly, an extremely small amount of the sintering additive was added to enhance the densification, which reduces the sintering time and temperature. In particular, up to 0.5 weight % of boron compounds as sintering additives were used to achieve a near full density in the final part. Thus, the starting powder, consisting of two distinct SS powders and sintering additive, is mixed before building a part in a layer-by-layer fashion. After completing the printing process with a binder phase, the printed powders are cured and the binder phase is burned out at 460 °C before sintering at 1250 °C for 6hours in a vacuum furnace to reach near-full densities (up to 99.6%). A subtle difference between SS 420 and SS 316 was evident because the enhanced oxidation during the binder burnout cycle on SS 316 due to a higher surface area of the SS 316 powder used in the experiment. The main contribution of this work is to provide the BJP process an important ability to fully consolidate the powders under an isothermal condition, which enable us to produce the final parts without residual stresses.

      PubDate: 2017-04-17T15:21:39Z
      DOI: 10.1016/j.ijmachtools.2017.04.006
       
  • A build surface study of Powder-Bed Electron Beam Additive Manufacturing
           by 3D thermo-fluid simulation and white-light interferometry
    • Authors: Subin Shrestha; Kevin Chou
      Abstract: Publication date: Available online 11 April 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Subin Shrestha, Kevin Chou
      In this study, a three dimensional (3D) thermo-fluid model for the Powder Bed Electron Beam Additive Manufacturing (PB-EBAM) process was developed using ANSYS FLUENT software. Temperature dependence of both the surface tension and material physical properties was incorporated. In addition, the melt-pool free-surface dynamics was established using the volume of fluid (VOF) approach, taking into account the energy, volume fraction and flow equations at the interface when heated by a moving heat source. The developed model was applied to study the beam speed effect in the raster scanning scenario. In addition, the surfaces of PB-EBAM-fabricated Ti-6Al-4V parts were analyzed using a white-light interferometer. The results show that, in general the build surface roughness along the beam moving direction slightly increases with the scanning speed. On the other hand, the hatch spacing noticeably affects the surface roughness in the transverse direction. The experimentally acquired average surface roughness increased from about 3µm for lower speed about 483mm/s to 11µm for higher speed case about 1193mm/s. In addition, the average roughness of 4.28µm, 5.5µm, and 9.84µm were obtained from simulation for different beam speeds which shows similar trend as that of experiment.

      PubDate: 2017-04-17T15:21:39Z
      DOI: 10.1016/j.ijmachtools.2017.04.005
       
  • Compensation of Frequency Response Function Measurements by Inverse RCSA
    • Authors: Kadir Kiran; Harsha Satyanarayana; Tony Schmitz
      Abstract: Publication date: Available online 8 April 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Kadir Kiran, Harsha Satyanarayana, Tony Schmitz
      This paper describes an analytical approach for compensating accelerometer-based (contact-type) modal testing results for both mass loading and cable energy dissipation (damping). The inverse Receptance Coupling Substructure Analysis (RCSA) approach is implemented, where a lumped parameter model of the accelerometer-cable is decoupled from the measured receptance (or frequency response function) to isolate the structure's receptance. Experimental results are presented for a 12.7 mm diameter cantilever rod, a 6.35 mm diameter cantilever rod, and clamped-clamped-clamped-free boundary condition thin ribs.

      PubDate: 2017-04-10T11:54:27Z
      DOI: 10.1016/j.ijmachtools.2017.04.004
       
  • A five-axis geometric errors calibration model based on the common
           perpendicular line (CPL) transformation using the product of exponentials
           (POE) formula
    • Authors: Yu Qiao; Youping Chen; Jixiang Yang; Bing Chen
      Abstract: Publication date: Available online 7 April 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Yu Qiao, Youping Chen, Jixiang Yang, Bing Chen
      Geometric error calibration is a key procedure to improve machining accuracy of five-axis CNC machine tools. This paper proposes a new position independent geometric errors (PIGEs) calibration model of five-axis serial machine tools based on the product of exponentials (POE) formula. The proposed model is characterized by the common perpendicular line (CPL) transformation which is adopted to express the deviation between the nominal axis twist and the actual one. One major advantage of the proposed model is the axis twists in the proposed calibration procedure with CPL model strictly fit the constraints of the revolute axis and prismatic axis, thus the calibration procedure avoids the normalization and orthogonalization as required by existing calibration models based on POE formula. The other advantage of the proposed CPL model is that it only needs 4 independent parameters for PIGEs of a revolute axis and 2 for PIGEs of a prismatic axis, rather than 6 parameters for each axis as required by existing models. Apparently, the decrease of parameters brings a shrink to the scale of the identification coefficient matrix, and thus decreases the calculation amount. The proposed model is validated by simulations and experiments.

      PubDate: 2017-04-10T11:54:27Z
      DOI: 10.1016/j.ijmachtools.2017.04.003
       
  • A study on laser multi-focus separation technology of thick KDP crystal
    • Authors: Peng Liu; Leimin Deng; Jun Duan; Baoye Wu; Xiaoyan Zeng; Ying Shangguan; Xizhao Wang
      Abstract: Publication date: Available online 7 April 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Peng Liu, Leimin Deng, Jun Duan, Baoye Wu, Xiaoyan Zeng, Ying Shangguan, Xizhao Wang
      KDP crystal is an important electro-optic material in various laser systems, and belongs to very difficult-to-cut material, especially for thick crystals. In this study, an innovative separation method—laser multi-focus separation technology (LMFS) for thick KDP crystal has been developed by skillfully combining femtosecond laser and LMFS optical system of fiber laser for the first time. In this way, the uniformities of temperature and thermal stress distributions along crystal thickness and the utilization efficiency of the laser energy are greatly improved. A penetration crack along crystal thickness could be formed and its propagation direction could be controlled to achieve safe and high-quality separation. The separating thickness of LMFS (50 mm) is at least 4 times thicker than that of existing laser separating technologies, and the separating efficiency of LMFS (200 μm/s) is at least 20 times faster than that of traditional mechanical methods. The generation mechanism of multi-focus was expounded by optical analysis and design, and verified by an established LMFS optical system. A numerical simulation was also established to analyze the dynamic distributions of temperature and thermal stress of KDP crystal generated by the LMFS optical system, and explore the separation mechanism of LMFS. In addition, a window of appropriate processing parameters was predicted by a series of numerical simulations to successfully separate a thick KDP crystal with the thickness of 50 mm. The quality of the separated sidewall surface was clean and flat (roughness of 10.857nm, flatness of 3.5389 μm) without any contamination, subsurface damage and edge fragmentation. The experimental results proved the feasibility of LMFS, and are in good agreement with the theoretical analysis.
      Graphical abstract image

      PubDate: 2017-04-10T11:54:27Z
      DOI: 10.1016/j.ijmachtools.2017.04.002
       
  • Modeling of the Instantaneous Milling Force per Tooth with Tool Run-out
           Effect in High Speed Ball-end Milling
    • Authors: Zhu Kunpeng; Zhang Yu
      Abstract: Publication date: Available online 6 April 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhu Kunpeng, Zhang Yu
      In the high speed milling, the tool run-out affects the cutting force greatly and results in pre-matured tool life. To investigate this relationship, an improved instantaneous milling force per tooth is proposed, with inclusion of tool run-out effect. The un-deformed chip thickness considering tool run-out are defined and modeled, according to the geometrical relationships and axial milling ranges per tooth. Meanwhile, instead of the studying the conventional average flank wear, tool wear per tooth is studied for more sensitive correlation with force. Based on milling tests with Inconel 718, the error of the force model prediction is found less than 1% against the experimental data, and the correlation between the axial instantaneous milling force and tool wear per tooth is above 0.9. The results have shown that the proposed model can accurately describe the instantaneous force per tooth including tool run out effect, and the axial force component is a good indication of tool wear condition.

      PubDate: 2017-04-10T11:54:27Z
      DOI: 10.1016/j.ijmachtools.2017.04.001
       
  • On the correlation between thermoelectricity and adhesive tool wear during
           blanking of aluminum sheets
    • Authors: Philipp Tröber; Hannes Alois Weiss; Thomas Kopp; Roland Golle; Wolfram Volk
      Abstract: Publication date: Available online 6 April 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Philipp Tröber, Hannes Alois Weiss, Thomas Kopp, Roland Golle, Wolfram Volk
      Blanking is one of the most frequently used manufacturing processes. Its profitability strongly depends on the development of tool wear, since this determines the decisive factors of part quality, process stability and service intervals. Reducing the wear can only be achieved by gaining a sufficient understanding of the interactions which cause it. One important factor in this context is the temperature increase in the shear zone due to the partial dissipation of inelastic work. The resulting temperature gradient in the tool, combined with the electric contact between the workpiece and the tool, generates thermoelectric voltages and currents. The thermoelectric currents are suspected to have an especially strong influence on adhesive wear, but the mutual correlation between them during blanking operations is not clear. Therefore, several blanking examinations were carried out with the aluminum alloy 5083. The thermoelectric currents and voltages were measured instantaneously in the tool and their impact on the development of wear was shown by externally manipulating the occurring thermoelectricity.

      PubDate: 2017-04-10T11:54:27Z
      DOI: 10.1016/j.ijmachtools.2017.03.005
       
  • Towards understanding the cutting and fracture mechanism in ceramic matrix
           composites
    • Authors: O. Gavalda Diaz; D.A. Axinte
      Abstract: Publication date: Available online 2 April 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): O. Gavalda Diaz, D.A. Axinte
      Ceramic Matrix Composites (CMCs) are increasingly used for the manufacture of high-value parts for several industries such as the aerospace, nuclear and automotive. Nevertheless, their heterogenic, anisotropic and brittle nature make difficult to characterise the machining process and therefore, an in-depth understanding of the cutting mechanics is needed. In this regard, this paper aims to understand the different behaviours of CMCs while employing orthogonal cutting. The first part of this article proposes a novel theoretical approach to explain the different types of cutting behaviours (fracture and shear cutting) based on the inelastic and orthotropic properties of the CMC's by using a high imaging system and measuring the cutting forces. The second part aims to understand the cutting and fracture mechanism by developing for the first time a specific analytical model for each of the three main orthotropic orientations, defined by the three main relative fibre orientations respect to the feed direction, which are found in cutting of CMCs. This is approached by the calculation of the specific cutting energy needed to fracture the CMC's during cutting (energy release rate, G c ) using fracture mechanics and cutting theories. This analytical model has been successfully validated for a Carbon/Carbon composite with the experimental data obtained for the brittle cutting and by introducing the concept of a rising R-curve in cutting models. Moreover, comparing the results obtained for the energy release rate for the brittle and semi-ductile mode, it is observed that the material experiences an important change in the energy release rate according to the brittle-to-semi-ductile transition occurring while reducing the depth of cut. Finally, a novel monitoring method based on the vibrations of the sample has been found successful to understand the type of crack formation appearing while cutting CMCs.

      PubDate: 2017-04-03T11:45:39Z
      DOI: 10.1016/j.ijmachtools.2017.03.008
       
  • Abrasive cylindrical brush behaviour in surface processing
    • Authors: František Novotný; Marcel Horák; Michal Starý
      Abstract: Publication date: Available online 31 March 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): František Novotný, Marcel Horák, Michal Starý
      Mechanical disintegration of glass surface layers by the action of composite filaments of a cylindrical brush is a new and unique technology for flat glass frosting. So far, similar tools have been used for metal treatment, e.g. for tool edge grinding or for surface treatment of stainless metal sheets. The technology has a high application potential, and facilitates the creation of new types of products for use in the fields of interior glass, domestic architecture, furniture, and lighting. Firstly, the paper describes the theoretical solutions of the new principle of frosting, and how the acquired knowledge can have a wider applicability in the fields of deburring, grinding of surfaces and edges of metal materials etc. Then, it presents a simulation of the kinetics of a separate filament brush, including an evaluation of the marks formed. Subsequently, the results are verified by laboratory experiments. In the conclusion, we recommend technical conditions for implementing the process of surface frosting.
      Graphical abstract image

      PubDate: 2017-04-03T11:45:39Z
      DOI: 10.1016/j.ijmachtools.2017.03.006
       
  • Mechanics of turn-milling operations
    • Authors: Alptunc Comak; Yusuf Altintas
      Abstract: Publication date: Available online 30 March 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Alptunc Comak, Yusuf Altintas
      Turn-milling machines, which are capable of carrying out turning and milling operations, are widely used in machining complex parts in one set-up. However, due to the complex kinematics and tool-workpiece interaction, turn milling operations are mainly carried out by relying on costly machining trials and experience. This paper presents the mechanics of turn-milling operations to predict cutting forces, torque and power requirements. Typical turn milling process involves three linear (x,y.z) and two rotary drives of the machine tool. The resulting feed vector is modeled as a function of linear velocities of the drives, and angular speeds of workpiece and tool spindles. The generalized chip thickness distribution is modeled as a function of linear feed drive motions, tool and workpiece spindle rotations. The cutting force predictions are experimentally verified for sample cylindrical and ball end mills. The identification of productive tool and workpiece spindle speeds is demonstrated using chip load limit of the tools and torque-power constraints of the turn milling machine tools.

      PubDate: 2017-04-03T11:45:39Z
      DOI: 10.1016/j.ijmachtools.2017.03.007
       
  • IFC - Editorial board
    • Abstract: Publication date: June 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 117


      PubDate: 2017-03-27T10:58:49Z
       
  • Milling chatter suppression in viscous fluid: a feasibility study
    • Authors: Zhao Zhang; Hongguang Li; Guang Meng; Song Ren
      Abstract: Publication date: Available online 18 March 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhao Zhang, Hongguang Li, Guang Meng, Song Ren
      During the machining process, chatter is the key factor that limits productivity. In the present study, experimental investigations are concerned which assess the feasibility by submerging the milling system in viscous fluid to mitigate milling chatter. Higher stability limit is obtained with the proposed approach, which indicates that the milling efficiency can be improved greatly under viscous fluid condition. The stability improvement can be attributed to the variations of the milling system dynamic characteristics and cutting force coefficients. Due to the extra energy loss, the damping of the milling system increases significantly under viscous fluid condition. The rigidity of the workpiece remains unchanged while the frequency of the milling system decreases due to the added mass of the viscous fluid. Additionally, the cutting force coefficients are calibrated and the results indicate that compared with the dry milling the cutting force coefficients reduce significantly under viscous fluid condition. The explanations are verified by the experiments, which validate the effectiveness of the proposed approach on the suppression of milling chatter.

      PubDate: 2017-03-20T03:16:31Z
      DOI: 10.1016/j.ijmachtools.2017.02.005
       
  • Laser Powder Bed Fusion of Nickel Alloy 625: Experimental Investigations
           of Effects of Process Parameters on Melt Pool Size and Shape with Spatter
           Analysis
    • Authors: Luis E. Criales; Yiğit M. Arısoy; Brandon Lane; Shawn Moylan; Alkan Donmez; Tuğrul Özel
      Abstract: Publication date: Available online 18 March 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Luis E. Criales, Yiğit M. Arısoy, Brandon Lane, Shawn Moylan, Alkan Donmez, Tuğrul Özel
      Laser powder bed fusion (L-PBF) as an metal additive manufacturing process that can produce fully dense 3D structures with complex geometry using difficult-to-process metal powders such as nickel-based alloy 625 which is one of the choice of metal materials for fabricating components in jet engines and gas turbines due to its high strength at elevated temperatures. L-PBF process parameters and scan strategy affect the resultant built quality and structural integrity. This study presents experimental investigations of the effects of process parameters and scan strategy on the relative density, melt pool size and shape. Fabricated test coupons were analyzed with two objectives in mind: i) to determine how close each coupon was to fully dense and ii) to determine melt pool dimensions (width and depth) and shape for each coupon. The identification and definition of a dynamic melt pool has been performed, a condition which indicates that melt pool geometry is constantly changing as the laser scans and moves along a single track. In order to gain in-depth understanding of the laser fusion processing of powder material, an in-situ thermal camera video recording is performed and analyzed for meltpool size, spattering particles, and heating and cooling rates during processing of powder material nickel alloy 625. The results reveal in-depth process information that can be used for further validation of modelling studies and adopted for the industrial practice.

      PubDate: 2017-03-20T03:16:31Z
      DOI: 10.1016/j.ijmachtools.2017.03.004
       
  • Machined Surface Temperature in Hard Turning
    • Authors: Lei Chen; Bruce L. Tai; Rahul G. Chaudhari; Xiaozhong Song; Albert J. Shih
      Abstract: Publication date: Available online 16 March 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Lei Chen, Bruce L. Tai, Rahul G. Chaudhari, Xiaozhong Song, Albert J. Shih
      Machined surface temperature is critical in turning of hardened steels because high surface temperature can lead to the formation of the white layer, which may have negative impacts on the steel fatigue life. This paper presents two experimental methods to measure machined surface temperatures in hard turning. The first method, based on a tool-foil thermocouple, estimates the machined surface temperature using a metal foil embedded in the workpiece to measure the tool tip temperature. The second method uses a thermocouple embedded in the tool with its tip continuously sliding on the machined surface behind the cutting edge during hard turning. A three-dimensional thermal model is developed and the inverse heat transfer method is applied to find the machined surface temperature near the cutting edge. For validation, hard turning tests were conducted and the cutting forces, tool-foil voltages and embedded thermocouple voltages were measured simultaneously at three levels of feed rates. The peak machined surface temperature occurred along the intersection of cutting edge and the machined surface. Its magnitude was mainly determined by the shear plane heat source and further increased due to flank face frictional heat source. Measurement results showed comparable predictions between the two developed methods with an average deviation of 30°C over the 500°C to 800°C range. These two methods, although based on very different approaches, have both proven feasible for the measurement of hard turning machined surface temperatures.

      PubDate: 2017-03-20T03:16:31Z
      DOI: 10.1016/j.ijmachtools.2017.03.003
       
  • A Model of Tool Wear in Electrical Discharge Machining Process Based on
           Electromagnetic Theory
    • Authors: Jingyu Pei; Lenan Zhang; Jianyi Du; Xiaoshun Zhuang; Zhaowei Zhou; Shunkun Wu; Yetian Zhu
      Abstract: Publication date: Available online 7 March 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jingyu Pei, Lenan Zhang, Jianyi Du, Xiaoshun Zhuang, Zhaowei Zhou, Shunkun Wu, Yetian Zhu
      In electrical discharge machining (EDM) process, tool wear is an inevitable phenomenon that adversely affects the geometrical accuracy of machined features. A theoretical model accounting for tool wear during EDM process is hence the basis study for high precision machining. However, in most modeling studies on tool wear and electrode shape, the sparking process is only factorized by the geometric configuration, i.e. the distance between electrodes. The real sparking process related to the fundamental physics is not addressed in these geometric models, which can produce large discrepancies with the experimental results. In this paper, a model of tool wear in EDM is proposed, which accounts for the electric field inside the dielectric fluid using electromagnetic (EM) theory. The spark is proposed to occur at the position where the local electric intensity reaches maximum and exceeds the breakdown strength of the dielectric fluid. This model is shown to provide the physical insight of the real EDM situation, and to give a more accurate prediction of tool wear compared with traditional geometric property based modeling. With these merits, this proposed model can be applied to predict tool wear in various machining processes. To evaluate this model, simulations of EDM die sinking and ED milling are carried out. The results by this electric field model were compared with both geometric model and experiments. By analyzing the profiles of the tool end, the differences in mechanism between the electric field and geometric model are identified. In addition, this electric field model is also applied to simulate the conic tool forming process in the fix-length compensation with micro-milling, which cannot be thoroughly addressed by the geometric model. The model presented in this paper is capable of capturing the key features of the tool wear in a variety of machining processes.

      PubDate: 2017-03-08T20:28:24Z
      DOI: 10.1016/j.ijmachtools.2017.03.001
       
  • Erratum to “Effect of friction at chip-tool interface on chip geometry
           and chip snarling” [Int. J. Mach. Tools Manuf. 107 (2016) 60–65]
    • Authors: Yasuyoshi Saito; Shoki Takiguchi; Takeshi Yamaguchi; Kei Shibata; Takeshi Kubo; Wataru Watanabe; Satoru Oyama; Kazuo Hokkirigawa
      Abstract: Publication date: Available online 6 March 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Yasuyoshi Saito, Shoki Takiguchi, Takeshi Yamaguchi, Kei Shibata, Takeshi Kubo, Wataru Watanabe, Satoru Oyama, Kazuo Hokkirigawa


      PubDate: 2017-03-08T20:28:24Z
      DOI: 10.1016/j.ijmachtools.2017.02.004
       
  • IFC - Editorial board
    • Abstract: Publication date: May 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 116


      PubDate: 2017-03-02T11:26:59Z
       
  • IFC - Editorial board
    • Abstract: Publication date: April 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 115


      PubDate: 2017-03-02T11:26:59Z
       
  • Effect of non-proportional damping on the dynamics and stability of
           multi-cutter turning systems
    • Authors: Marta Janka Reith; Gabor Stepan
      Abstract: Publication date: Available online 28 February 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Marta Janka Reith, Gabor Stepan
      Parallel turning operations offer considerable potential in increasing productivity, since they ensure high material removal rates and high feasible accuracy simultaneously. According to preliminary calculations, the stable parameter region for a 2-cutter turning system can significantly be extended by its dynamical detuning via modifying the natural frequency of one of the tools. Mechanical models are presented for a 2-cutter turning tool fixture to predict the dynamics and stability properties of the system. First, a 2-degree-of-freedom (DoF) model with dynamically uncoupled cutters is analysed. A test fixture incorporating 2 cutters was built, in order to verify theoretical predictions on cutting stability. Measurement results resulted in the extension of the mechanical model with another DoF, which captures the physical coupling between the tools. Experiments indicate that for close natural frequencies, the corresponding modal dampings are essentially different, consequently, the damping properties of the 3-DoF model can properly be modelled by non-proportional damping only. It is also shown that the presence of this non-proportional damping results in a significant increase in the robust chip width limit of stable cutting, which enhances the effect of detuning the tool frequencies in the 2-cutter turning system even further.

      PubDate: 2017-03-02T11:26:59Z
      DOI: 10.1016/j.ijmachtools.2017.02.006
       
  • An experimental investigation and modeling of micro array replication with
           Zr-based bulk metallic glass using a hot embossing process
    • Authors: Xiang Zhang; Yongsheng Luo; Junfeng Li; Bowen Dun; Shiyang He; Shujie Yan; Qian Li
      Abstract: Publication date: Available online 14 February 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Xiang Zhang, Yongsheng Luo, Junfeng Li, Bowen Dun, Shiyang He, Shujie Yan, Qian Li
      Zirconium-based bulk metallic glass (Zr-based BMG) is a potential material for micro/nano molds. In this study, we investigated the flow characteristics of Zr-based BMG in the supercooled liquid region (SLR) with a series of uniaxial compression tests. The Newtonian viscosity model of Zr-based BMG is constructed by fitting with the experimental results based on the Arrhenius equation. The hot embossing process which can be seen as a combination of two kinds of simultaneous flows is theoretically analyzed based on Navier-Stokes (N-S) equations. The velocity and pressure fields in a BMG sample have been evaluated. Two kinds of filling modes are proposed considering the interfacial tension and oxide layer that forms on the BMG surface. The exact solutions are obtained when the cavities of the micro arrays are circular, triangular and rectangular in shape based on N-S equations. The theoretical solutions, considered surface resistance, are in good agreement with our experimental results. These models can be used to describe the fillings of metallic glass in micro hot embossing process. Finally, we studied the effects of micro cavity size and shape on BMG filling, and found that the cavities of micro rectangular array are easier filling in same feature size, however, the cavities of micro circular array are easier filling in same area. The exact models developed in this paper can be used to calculate the BMG filling heights in the cavities of micro arrays and verify the reliability of simulation results in future mold designs.

      PubDate: 2017-02-16T05:03:14Z
      DOI: 10.1016/j.ijmachtools.2017.02.003
       
  • Surface Roughness of Two-Frequency Elliptical Vibration Texturing (TFEVT)
           Method for Micro-Dimple Pattern Process
    • Authors: Rendi Kurniawan; Gandjar Kiswanto; Tae Jo Ko
      Abstract: Publication date: Available online 19 January 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Rendi Kurniawan, Gandjar Kiswanto, Tae Jo Ko
      This study presents a two-frequency elliptical vibration texturing (TFEVT) method that adds elliptical vibration cutting (EVC) to a conventional texturing (CT) method. The TFEVT method improves the surface roughness compared to the CT method during a micro-dimple texturing process. Kinematic analysis and a theoretical surface roughness model are presented based on the effect of the tool edge radius. The effect of this radius cannot be neglected since it is nearly equal to the undeformed chip thickness at the micro scale. The replication of the tool edge radius profile, the effect of the material spring back, and the residual error were also considered in the surface roughness model. The surface roughness of a micro-dimple also includes the replication of the tool edge radius profile, which can be determined by using a replication technique. The deflection of material spring back is formulated according to the value of the minimum principal stress in the tertiary deformation zone between the flank face and the machined surface, and the plastic strain value is determined based on elasto-plastic deformation theory. Experimental and simulation results were compared to validate the surface roughness model.

      PubDate: 2017-01-21T00:49:39Z
      DOI: 10.1016/j.ijmachtools.2016.12.011
       
  • Porosity evolution and its thermodynamic mechanism of randomly packed
           powder-bed during selective laser melting of Inconel 718 alloy
    • Authors: Mujian Xia; Dongdong Gu; Guanqun Yu; Donghua Dai; Hongyu Chen; Qimin Shi
      Abstract: Publication date: Available online 17 January 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Mujian Xia, Dongdong Gu, Guanqun Yu, Donghua Dai, Hongyu Chen, Qimin Shi
      To further investigate the porosity evolution during selective laser melting (SLM) Inconel 718 alloy, a transient mesoscale model with a randomly packed powder-bed has been proposed by finite volume method (FVM), taking consideration of the phase transition, variation of thermo-physical properties and interfacial force. The thermodynamics within molten pool and resulting porosity evolution behavior of a set of laser scanned tracks with various laser scanning speeds were studied using numerical approach. The results evidently revealed that the operating peak temperature was reduced obviously as increasing the scanning speeds. Accordingly, the high cooling rate, short lifespan and limiting depth of pool and small velocity of molten liquid flow were obtained under a high scanning speed. Scanning speed played a crucial role in determining the type of porosity in the terminally SLM-processed Inconel 718 components. At a high scanning speed of 500 mm/s, the top surface was primarily dominated by open porosity, accompanying with large-sized inter-layer porosity on the cross section, due to a limiting energy input penetrated into the powder-bed and incomplete melting of powder. By contrast, as a relatively low scanning speed of 200 mm/s was employed, the top surface appeared to be smooth free of less metallurgical porosity and no apparent inter-layer porosity on the cross section surface attributing to the escaping of porosity, indicating an well metallurgical bonding of the neighboring layer towards the building direction. Simultaneously, the physical mechanism was thoroughly discussed. The simulated distribution of porosity was found to be consistent with the experimental measurements.
      Graphical abstract image

      PubDate: 2017-01-21T00:49:39Z
      DOI: 10.1016/j.ijmachtools.2017.01.005
       
  • A novel cutting tool design to avoid surface damage in bone machining
    • Authors: Zhirong Liao; Dragos A. Axinte; Dong Gao
      Abstract: Publication date: Available online 12 January 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhirong Liao, Dragos A. Axinte, Dong Gao
      With its anisotropic structure, bone machining occurs as shear/serrated cutting mechanisms at low values of uncut chip thickness while at high values it results in fracture cutting mechanisms which lead to significant tissues damages; hence, utilising conventional tools at high material removal rates comes with drawback on surface damages, situation that needs to be avoided. This paper reports on a novel design of a milling cutter which includes on the back of main cutting edge a succession of micro-cutting edges arranged on an Archimedes spiral that allows the limitation of surface damage. That is, by adjusting the feed rate, this tool design allows the change of the cutting mechanism as follows: (i) “shear/serrated” cutting mode: when the feed rate is smaller than a pre-established threshold, only the main cutting edges work which yields a shear/serrated cutting mechanism; (ii) combined “fracture & shear” cutting mode occurring at high feed rate caused by: the main cutting edges working in fracture cutting mechanism while the subsequent micro-cutting edges work under shear cutting mechanism, combination which leads to significant reduction of bone surface damages. This new tool concept was materialised on a solid diamond composite, characterised by excellent heat conduction and low wear rates. Cutting experiments with various values of feed rates showed that the proposed tool designed concept significantly reduced the fracture damage of bone cut surface as well as cutting temperature compared with the dimensionally equivalently conventional tool.

      PubDate: 2017-01-14T10:12:46Z
      DOI: 10.1016/j.ijmachtools.2017.01.003
       
  • On a stochastically grain-discretised model for 2D/3D temperature mapping
           prediction in grinding
    • Authors: Hao Nan Li; Dragos Axinte
      Abstract: Publication date: Available online 11 January 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Hao Nan Li, Dragos Axinte
      Excessive grinding heat might probably lead to unwanted heat damages of workpiece materials, most previous studies on grinding heat/temperature, however, assumed the wheel-workpiece contact zone as a moving band heat source, which might be not appropriate enough to capture the realistic situation in grinding. To address this, grinding temperature domain has been theoretically modeled in this paper by using a stochastically grain-discretised temperature model (SGDTM) with the consideration of grain-workpiece micro interactions (i.e. rubbing, ploughing and cutting), and the full 2D/3D temperature maps with highly-localised thermal information, even at the grain scale (i.e. with the thermal impacts induced by each individual grain), has been presented for the first time. To validate theoretical maps, a new methodological approach to capture 2D/3D temperature maps based on an array of sacrificial thermocouples have also been proposed. Experimental validation has indicated that the grinding temperature calculated by SGDTM showed a reasonable agreement with the experimental one in terms of both 1D temperature signals (i.e. the signals that are captured at a specific location within the grinding zone) and the 2D/3D temperature maps of the grinding zone, proving the feasibility and the accuracy of SGDTM. This study has also proved that, as expected, the heat fluxes are neither uniformly-distributed along the wheel width direction nor continuous along the workpiece feed direction. The proposed SGDTM and the temperature measurement technique are not only anticipated to be powerful to provide the basis for the prevention of grinding thermal damage (e.g. grinding burns, grinding annealing and rehardening), but also expected to be meaningful to enhance the existing understanding of grinding heat/temperature than using the common approach depending on the single thermocouple technique.

      PubDate: 2017-01-14T10:12:46Z
      DOI: 10.1016/j.ijmachtools.2017.01.004
       
  • Heat transfer and material ablation in hybrid laser-waterjet microgrooving
           of single crystalline germanium
    • Authors: Hao Zhu; Jun Wang; Peng Yao; Chuanzhen Huang
      Abstract: Publication date: Available online 5 January 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Hao Zhu, Jun Wang, Peng Yao, Chuanzhen Huang
      A numerical model describing the heat transfer and material ablation in a hybrid laser-waterjet microgrooving process for a single crystalline germanium (Ge) is developed, considering the relevant physical phenomena involved, such as laser-induced plasma (or optical breakdown) in water, laser beam attenuation in the plasma zone, heat transfer in Ge substrates, and waterjet cooling and impinging effects. The model is then verified, which shows that the respective calculated and measured quantities are in reasonably good agreement. A numerical simulation study is then carried out using the developed model and demonstrates that the shielding effect of the laser-induced plasma increases with the laser pulse energy. In addition, the irradiated material can be expelled by a waterjet at its soft-solid status, and heat accumulation in the workpiece is effectively removed by the waterjet cooling effect during the off-pulse period, so that laser heating induced thermal damage is minimized. The effect of processing parameters on the ablation process is also analysed. It has been noticed that an increase in laser pulse energy leads to a deeper groove, and an increase in the applied water pressure decreases the threshold workpiece temperature for material removal.

      PubDate: 2017-01-06T10:07:38Z
      DOI: 10.1016/j.ijmachtools.2017.01.002
       
  • Singularities in five-axis machining: cause, effect and avoidance
    • Authors: R.J. Cripps; B. Cross; M. Hunt; G. Mullineux
      Abstract: Publication date: Available online 31 December 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): R.J. Cripps, B. Cross, M. Hunt, G. Mullineux
      Singular configurations of five-axis machines have long been observed. Machining near to such singularities drastically affects the behaviour of machine axes movements. Singularities have been linked to the kinematic chain of the machine configuration but not necessarily machine axes movement. The first contribution of this paper is a link between cutter motion in work-piece and machine coordinate systems. This leads to a description for the machine axes movements for a given tool path. Unstable machine axes movements are discovered near singular configurations of the rotary axes. By relating these configurations to orientations in the workpiece coordinate system, a simple approach that avoids singularities by reorienting the workpiece is proposed. Machining tests verify the effectiveness of this approach.

      PubDate: 2017-01-06T10:07:38Z
      DOI: 10.1016/j.ijmachtools.2016.12.002
       
  • A NURBS interpolator with constant speed at feedrate-sensitive regions
           under drive and contour-error constraints
    • Authors: Zhen-yuan Jia; De-ning Song; Jian-wei Ma; Guo-qing Hu; Wei-wei Su
      Abstract: Publication date: Available online 22 December 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhen-yuan Jia, De-ning Song, Jian-wei Ma, Guo-qing Hu, Wei-wei Su
      This paper presents a systematic NURBS interpolator with constant speed at feedrate-sensitive regions under drive and contour-error constraints to generate a smooth and contour-error limited NURBS toolpath without a large feedrate variation, thus balancing the machining quality, precision, and efficiency. After introducing the concept of feedrate-sensitive regions, the scheduled feedrate in this paper keeps constant at most areas and only varies smoothly within partial of the transition regions, which is beneficial to the machining quality. The servo-lag induced contour error in real machining is considered as an additional constraint accompanied by the geometric and drive constraints during feedrate scheduling, so that the contour error can be bounded from the source, thus improving the machining precision. A 2nd-order Runge-Kutta parametric interpolation method with parameter compensation and transition-point feedrate correction, based on displacement-controlled feedrate generation, is presented for generation of not only the smooth feedrate profile without abrupt change at transition points between constant and variable speed regions, but also the desired interpolation points with an extremely small feedrate fluctuation. The proposed systematic interpolation method contains two blocks: offline pre-processor and online interpolator. The parameter-feedrate set of acceleration/deceleration-start points is created in the pre-processor such that the smooth feedrate profile and desired toolpath can be generated in the online interpolator without complex look-ahead algorithms. Performance of the presented interpolator are evaluated both by simulations and by experimental tests.

      PubDate: 2016-12-26T08:43:25Z
      DOI: 10.1016/j.ijmachtools.2016.12.007
       
  • A novel multi-jet polishing process and tool for high-efficiency polishing
    • Authors: C.J. Wang; C.F. Cheung; L.T. Ho; M.Y Liu; W.B. Lee
      Abstract: Publication date: Available online 18 December 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): C.J. Wang, C.F. Cheung, L.T. Ho, M.Y Liu, W.B. Lee
      Traditional fluid jet polishing (FJP) is limited by its low material removal rate and its applicability to medium-large size surfaces. This paper presents a novel multi-jet polishing (MJP) process and tools based on FJP which can implement high-efficiency polishing on large-scale surfaces or lens array surfaces. The MJP makes use of a purposely designed nozzle which possesses many regularly distributed holes, whose number can be a few to several hundred. Moreover, each hole can spray out a high-energy fluid jet leading to a dramatic increase of material removal. Its feasibility is firstly analyzed through a Computational Fluid Dynamics (CFD) simulation. Hence, its surface generation mechanisms in the integrated polishing mode and discrete polishing mode are studied. After that, a series of polishing experiments on different materials are conducted to validate its polishing performance as compared to single jet polishing (SJP). The experimental results show that the MJP tool can realize a much higher material removal rate, together with compatible surface roughness to SJP. Hence, the MJP tool has the potential to implement high-efficiency polishing on medium-large size surfaces and lens array surfaces.
      Graphical abstract image

      PubDate: 2016-12-19T07:56:27Z
      DOI: 10.1016/j.ijmachtools.2016.12.006
       
  • Multiple criteria optimisation in coated abrasive grinding of titanium
           alloy using minimum quantity lubrication
    • Authors: Chunliang Kuo; Yichia Hsu; Chunhui Chung; Chao-Chang Arthur Chen
      Abstract: Publication date: Available online 16 December 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Chunliang Kuo, Yichia Hsu, Chunhui Chung, Chao-Chang Arthur Chen
      This paper investigates the influences of minimum quantity lubrication (MQL) to material removal, surface integrity and temperature in the grinding of titanium alloys (Ti-6Al-4V) using coated abrasive discs. Titanium alloys are used for the slumping moulds when shaping soda-lime glass, due to their good corrosion resistance. However, during the grinding process the temperature can be over 300 ℃ in microseconds due to the inherent low thermal conductivity of titanium alloys, leading to a degradation of surface quality and integrity. In this work, the developed grinding model considers the effects of grit number, grinding speed, normal load pressure and MQL on the grinding force ratio. The developed model, which was composed of operating parameters, was calibrated by experimental results such as grit number, grinding speed, normal load pressure and the use of MQL to a precision level of 83.98%. The produced ultra-fine surface (~Ra 0.1 μm) demonstrates the progression of the adhesion, the plastic deformation following the fretting and sealing actions on the workpiece surface. The improvement of the surface integrity in its microhardness (~395HV0.025) prolonged the tool life and benefited the productivity. The observed objectives in the material removal rate and surface quality are influenced by the operating abrasives, grinding speed, normal loading pressure and blasting pressure in the grinding action. The control of the thresholds in the load and temperature could vary the surface conditions; whilst MQL provided instant effects to the work's hardening and thermal softening in grinding. The developed multiple criteria model in the response surface method (RSM), suggests the optimised parameter set and results when weightings of surface roughness and material removal rate are given.

      PubDate: 2016-12-19T07:56:27Z
      DOI: 10.1016/j.ijmachtools.2016.12.004
       
  • Brittle-ductile transition in shape adaptive grinding (SAG) of SiC
           aspheric optics
    • Authors: Anthony Beaucamp; Peter Simon; Phillip Charlton; Christopher King; Atsushi Matsubara; Konrad Wegener
      Abstract: Publication date: Available online 30 November 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Anthony Beaucamp, Peter Simon, Phillip Charlton, Christopher King, Atsushi Matsubara, Konrad Wegener
      Silicon carbide is a ceramic material with a desirable combination of high thermal and mechanical stability, making it ideal for optical application in aerospace and next generation lithography. It is however notoriously difficult to machine down to super-fine finish when the shape is other than flat or spherical. In this paper, we describe the application of a “semi-elastic” machining method called shape adaptive grinding (SAG), in which an elastic tool is combined with rigid pellets made of nickel or resin, to which super abrasives are bonded. A comprehensive model of the physical interaction between SAG tool and workpiece is proposed, and used to understand the mechanics driving brittle-ductile transition on ceramic materials such as SiC. Machining parameters adequate for optical finishing are then derived from the model and demonstrated on an aspheric silicon carbide workpiece, which was manufactured by reaction bonding and coated with a layer of pure SiC by chemical vapour deposition (CVD). Through SAG processing and final polishing, this aspheric mirror was improved from an initial form error of 40µm down to 112nm Peak-to-Valley, with no residual damage visible on the surface.
      Graphical abstract image

      PubDate: 2016-12-06T04:55:52Z
      DOI: 10.1016/j.ijmachtools.2016.11.006
       
  • Ductile machining of single-crystal silicon for microlens arrays by
           ultraprecision diamond turning using a slow tool servo
    • Authors: Mao Mukaida; Jiwang Yan
      Abstract: Publication date: Available online 27 November 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Mao Mukaida, Jiwang Yan
      Microlens arrays of single-crystal silicon are required increasingly in advanced IR optics. In this study, we attempted to machine spherical concave microlens arrays on a single-crystal silicon wafer by slow tool servo diamond turning. The form error, surface topography, material phase transformation, and cutting force characteristics were investigated experimentally. It was found that brittle fracture occurred preferentially at one side (the exit side of tool feed) of the lens dimples when cutting direction is along <110> and tool feed rate is high. Amorphous silicon phase was generated significantly at one side (the exit side of tool feed) of the dimples as tool feed rate increased. The peak values and the direction angles of cutting forces changed with tool feed rate, crystal orientation, and the cutting direction. Two kinds of tool wear, namely, micro chippings and flank wear were observed in different regions of the tool edge where undeformed chip thickness is different. Spherical microlens arrays with a form error of ~300 nmPV and surface roughness of ~6 nmSa were successfully fabricated.
      Graphical abstract image

      PubDate: 2016-11-29T02:02:03Z
      DOI: 10.1016/j.ijmachtools.2016.11.004
       
  • Damage-free finishing of CVD-SiC by a combination of dry plasma etching
           and plasma-assisted polishing
    • Authors: Hui Deng; Katsuyoshi Endo; Kazuya Yamamura
      Abstract: Publication date: Available online 26 November 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Hui Deng, Katsuyoshi Endo, Kazuya Yamamura
      To realize the damage-free finishing of CVD-SiC substrates, which are used as materials for space telescope mirrors and glass lens molds, plasma chemical vaporization machining (PCVM) and plasma-assisted polishing (PAP) were combined. In this study, the properties of such CVD-SiC substrates, including their surface morphology, composition and crystalline orientation, were investigated. Lapping using diamond abrasives and conventional chemical mechanical polishing (CMP) using CeO2 slurry were conducted for comparison with the proposed atmospheric-pressure-plasma-based finishing process. Many scratches and a subsurface damage (SSD) layer were formed by the diamond lapping of CVD-SiC. Conventional CMP using CeO2 slurry was conducted for the damage-free finishing of CVD-SiC. However, the polishing efficiency was very low. In the proposed process, PCVM, which is a noncontact dry etching process, was performed to remove the SSD layer while PAP, which combines plasma modification and soft abrasive polishing, was performed for damage-free surface finishing. PCVM was conducted on a diamond-lapped CVD-SiC surface. After PCVM for a short duration of 5min, the scratches and SSD layer formed by lapping were completely removed, although the surface roughness was slightly increased. PAP using a resin-bonded CeO2 grindstone was conducted to decrease the surface roughness of CVD-SiC processed by diamond lapping and PCVM for 5min, for which a loose-held-type grindstone was demonstrated to be very useful. A flat and scratch-free surface with an rms roughness of 0.6nm was obtained after PAP finishing.

      PubDate: 2016-11-29T02:02:03Z
      DOI: 10.1016/j.ijmachtools.2016.11.002
       
  • Variation of surface generation mechanisms in ultra-precision machining
           due to relative tool sharpness (RTS) and material properties
    • Authors: M. Azizur Rahman; M. Raihan Amrun; Mustafizur Rahman; A. Senthil Kumar
      Abstract: Publication date: Available online 23 November 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): M. Azizur Rahman, M. Raihan Amrun, Mustafizur Rahman, A. Senthil Kumar
      The need for ultra-fine surface generation by machining in micrometer and sub-micrometer scales is increasing rapidly for fabrication of micro products. However, there are limitations of bringing down the process from macro to micro to ultra-precision level due to the variation of the physical phenomenon responsible for surface generation process which is significantly dependent on tool edge radius. To analyze the tool edge radius effect, the governing process parameter identified as the ratio of undeformed chip thickness (a) to tool edge radius (r), which is known as relative tool sharpness, RTS (a/r). However, there are lacking of mathematical models to quantify the micro-mechanics of the material deformation during the surface generation process. In this study, a mathematical model has been established for the material removal mechanism with relation to edge radius effect. The novelty of this model lies in its ability to quantify the instantaneous material flow angle (φ ne ) for a particular tool-workpiece combination with relative tool sharpness (RTS). The proposed model is able to capture the trend of the change of surface generation mechanism from shearing to extrusion to ploughing and rubbing. The transition of the deformation behaviour is predicted form the mathematical model and orthogonal cutting experiments were conducted for the validation of the results for two materials (Mg and Cu alloy). Under identical machining conditions, micro-chips and machined surface integrity of Cu and Mg alloy exhibited different characteristics. For the best nanometric finishing, the ‘extrusion-like’ machining zone is identified where the RTS value for Cu alloy is found smaller than that for Mg alloy. Hence, smaller grain material (Cu alloy, ~35µm) provides smaller RTS value than larger grain material (Mg alloy, ~126µm) for achieving superior surface finishing. Therefore, material properties play an important role for the relative tool sharpness (RTS) during the variation of high quality surface generation mechanism.

      PubDate: 2016-11-29T02:02:03Z
      DOI: 10.1016/j.ijmachtools.2016.11.003
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs
Your IP address: 54.198.118.102
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2016