for Journals by Title or ISSN
for Articles by Keywords
help
  Subjects -> MANUFACTURING AND TECHNOLOGY (Total: 291 journals)
    - CERAMICS, GLASS AND POTTERY (26 journals)
    - MACHINERY (32 journals)
    - MANUFACTURING AND TECHNOLOGY (180 journals)
    - METROLOGY AND STANDARDIZATION (3 journals)
    - PACKAGING (15 journals)
    - PAINTS AND PROTECTIVE COATINGS (5 journals)
    - PLASTICS (28 journals)
    - RUBBER (2 journals)

MACHINERY (32 journals)

Showing 1 - 0 of 0 Journals sorted alphabetically
Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9)
Advanced Energy Materials     Hybrid Journal   (Followers: 21)
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: 19)
Electric Power Components and Systems     Hybrid Journal   (Followers: 6)
Engenharia Agrícola     Open Access  
Foundations and Trends® in Electronic Design Automation     Full-text available via subscription  
High Speed Machining     Open Access   (Followers: 3)
High Temperature Materials and Processes     Hybrid Journal   (Followers: 4)
International Journal of Machine Tools and Manufacture     Hybrid Journal   (Followers: 5)
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 Strain Analysis for Engineering Design     Hybrid Journal   (Followers: 6)
Journal of Terramechanics     Hybrid Journal   (Followers: 2)
Machine Design     Partially Free   (Followers: 91)
Machines     Open Access   (Followers: 2)
Materials     Open Access   (Followers: 6)
Mechanics Based Design of Structures and Machines: An International Journal     Hybrid Journal   (Followers: 3)
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]   [5 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0890-6955
   Published by Elsevier Homepage  [3039 journals]
  • Micro-Macro-Mechanical Model and Material Removal Mechanism of Machining
           Carbon Fiber Reinforced Polymer
    • Abstract: Publication date: Available online 14 September 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Bin Niu, Youliang Su, Rui Yang, Zhenyuan Jia
      The present paper studies the material removal mechanism of machining carbon fiber reinforced polymer (CFRP) by a micro-mechanical model, and proposes prediction models of cutting forces from the microscale to the macroscale. At the microscale, the micro-mechanical model for cutting a fiber in orthogonal cutting CFRP is established via the elastic foundation beam theory with explicit description of the carbon fiber and the matrix. The deflection and failure of the fiber constrained by the surrounding composite are analysed under the cutting effects by the tool edge. In addition, the fiber failure under the pressing of the flank face is analysed based on the undulating fiber theory. Analytical expressions are established at the microscale for evaluating the force for cutting a single fiber and the compression force for a single fiber from the flank face. At the macroscale, the chip length is determined by analyzing the characteristics of the cutting force signals of orthogonal cutting experiments. The characteristic chip length is used for establishing the trans-scale prediction model of cutting forces from the microscale to the macroscale. The total cutting and thrust forces at the macroscale during the formation of a chip are predicted based on the micro-mechanical results and the characteristic chip length, which agree well with the experimental results for orthogonal cutting of CFRP. Furthermore, the fiber failure modes and the debonding between the fiber and the matrix under different supporting conditions are discussed by the micro-mechanical model, by which subsurface damages are recognized.


      PubDate: 2016-09-19T05:23:41Z
       
  • Modeling and application of ring stiffness condition for radial-axial ring
           rolling
    • Abstract: Publication date: Available online 7 September 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Lin Hua, Jiadong Deng, Dongsheng Qian, Jian Lan, Hui Long
      Radial-axial ring rolling (RARR) is an advanced incremental metal-forming technology for manufacturing various seamless rings, especially for large scale rings. A primary problem for RARR is to facilitate rolling process stable and form a ring with good dimension and performance. However, RARR is an extremely complex dynamic rolling process with high flexibility. To reasonably control guide roll is an important approach to keep rolling process stable during RARR. In this paper, a mathematical model of ring stiffness condition for RARR was established based on the force method. Then the influence factors to ring stiffness were discussed, especially the section bending moment factor. To verify the ring stiffness model, finite element (FE) simulation was adopted. In addition, a comparison of different ring stiffness models was made. It can be found the proposed stiffness model has a high accuracy. Furthermore, a control method of the pressure in the hydraulic cylinder to adjust the guiding force based on the stiffness model was proposed. By FE simulation of RARR, an appropriate adjustment coefficient to determine the guiding force was obtained. Finally, an experiment of RARR for a large ring was carried out. The rolling process was very smooth and steady, and a super-large ring with diameter more than 9 m was manufactured successfully.


      PubDate: 2016-09-12T19:19:48Z
       
  • The Effects of Fluid Vapor Pressure and Viscosity on the Shapes of
           Abrasive Slurry-jet Micro-machined Holes and Channels
    • Abstract: Publication date: Available online 9 September 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): K. Kowsari, M.H. Amini, M. Papini, J.K. Spelt
      Abrasive slurry jet micro-machining (ASJM) can etch micro-features such as holes and channels in virtually any material. Holes, and to a lesser extent, channels machined in brittle materials using ASJM typically suffer from substantial edge rounding near the opening. This study investigated the erosive mechanism responsible for the rounding in borosilicate glass and sintered zirconium tin titanate targets, and determined the process parameters capable of minimizing the effect. Computational fluid dynamics (CFD) showed that the rounding that occurred during ASJM with a water-based slurry was due to the impact of particles accelerated by the formation and collapse of cavitation bubbles in regions where local pressures were below the vapor pressure of water. Further evidence of this was obtained by comparing the micro-topography in these regions with that produced by an ultrasonic cavitation apparatus in a water-particle slurry. Cavitation-enhanced erosion in ASJM was minimized using liquids such as mineral or soybean oil that have relatively low vapor pressures, resulting in blind and through-holes having sharp entrance and exit holes in glass and sintered zirconium tin titanate. The increased viscosity of the test fluids also altered the particle trajectories observed in the CFD models, causing the cross-sectional shape of the holes to have flatter bottoms and steeper sidewalls. In ductile targets such as copper, edge rounding due to cavitation-enhanced erosion was found to be much smaller than in brittle targets. In glass channels, the use of a soybean oil-based slurry eliminated the edge rounding and resulted in flatter bottoms, but increased the width by approximately 20%.


      PubDate: 2016-09-12T19:19:48Z
       
  • Research on the dynamics of ball screw feed system with high acceleration
    • Abstract: Publication date: Available online 6 September 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jun Zhang., Huijie Zhang, Chao Du, Wanhua Zhao
      For the ball screw feed system with high acceleration, the large inertial force derived from the moving components may change the real contact state of the system kinematic joints, resulting in the changes of the contact stiffness and hence the dynamic characteristics of the feed system. In this study, an equivalent dynamic model of the ball screw feed system is established using lumped parameter method considering the influence of the acceleration. Equivalent axial stiffnesses of screw-nut joints and bearing joints are both derived based on the contact state due to the variation of inertial force. The experiments on the ball screw feed system driven with different accelerations are also performed to verify the dynamic model proposed. The variation of the contact stiffness of the kinematic joints, transmission stiffness and natural frequency of the feed system are discussed with acceleration and the results show that they all reveal sudden changes when acceleration reaches a certain value. Total load, rated dynamic load and screw tension force have a great effect on the system natural frequency at different accelerations. The largest acceleration the feed system can reach is determined by the smaller one of the two critical accelerations for nut joints and bearing joints.


      PubDate: 2016-09-07T18:45:00Z
       
  • Functional Accuracy Investigation of Work-Holding Rotary Axes in Five-Axis
           CNC Machine Tools
    • Abstract: Publication date: Available online 6 September 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Mehrdad Vahebi Nojehdeh, Behrooz Arezoo
      Rotary axes error motions of five-axis CNC machine tools affect dimensional, geometrical and form accuracy of machined features according to structural design and sensitive direction considerations. Work carrying kinematic chains mostly use one rotary axis in radial Fixed Sensitive Direction (radial FSD) setup. The application keeps workpiece axis coaxial with the axis of rotation, preparing more flexibility for machining of complicated features. In spite of conspicuous advantages, in case of poor geometrical quality of machined features, lack of knowledge about error patterns makes the error source isolation process more difficult. This paper investigates the consequences of cycling error motions of radial FSD work-holding rotary axes, in order to prepare intuitive knowledge about possible error patterns. A virtual cutting module equipped with an error-mapping model is generated to simulate the cutting process in vicinity of different error motion scenarios. As a novel approach, comparison of measured deviations with available error patterns facilitates the error source isolation. Experimental results conducted on airfoil cutting process verified the effectiveness of the presented method.


      PubDate: 2016-09-07T18:45:00Z
       
  • Method for identifying feed-drive system dynamic properties using a motor
           current
    • Abstract: Publication date: Available online 1 September 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Xing Liu, Xinyong Mao, Hongqi Liu, Bin Li, Chuangfu Guan, Zisheng Zhang, Bo Luo, Fangyu Peng
      The dynamics of a machine tool ball screw is an important topic in high-precision machining. Capturing the axial and torsional dynamics of the ball screw has an important guiding significance to the stable processing of the machine tool. The traditional methods mainly involve a mounted sensor or direct embedment into the structure and hybrid finite element methods (FEMs), which are inconvenient. The FEM accuracy is limited by the accuracy of the model. This paper reports that feed-drive system vibration is excited by the interactive impact of a screw, ball, and nut, whose interaction is the core of the feed-drive system dynamics. Under the action of current, the ball screw serves as the transmission component of the executive component to control the working condition of the sliding table. This paper proposes a new method that uses the inertia force sequence caused by random idle running of the sliding table to identify the natural frequency of a feed-drive system based on the feed motor current response. First, the corresponding relationship between the current and the vibration of the feed-drive system is studied. The accuracy of the new method based on the current response is analysed by the experiment, which is performed to identify the natural frequency of the feed-drive system. Then, the incentive region is changed to study the identification effect under different interactive impact conditions, where the contact condition of the ball screw is different.


      PubDate: 2016-09-01T17:04:54Z
       
  • IFC - Editorial board
    • Abstract: Publication date: October 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 109




      PubDate: 2016-08-27T11:42:21Z
       
  • Novel Drill Structure for Damage Reduction in Drilling CFRP Composites
    • Abstract: Publication date: Available online 21 August 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhenyuan Jia, Rao Fu, Bin Niu, Baowei Qian, Yu Bai, Fuji Wang
      Drilling holes on CFRP components is inevitable for assembling process in the aviation industry. The drilling-induced damages frequently occur and affect not only the load carrying capacity of components but also the reliability. Therefore, it is of great urgency to enhance drilling quality on CFRP components. The article aims to propose a novel drill structure to change the cutting conditions at the drill exit and effectively reduce damages in drilling CFRP. Considering the drilling-exit constraint condition, a unique two-dimensional cutting model is established to represent the axial cutting of the main cutting edge at the drill exit. Based on the model, the effects of point of action and cutting direction on material removal at the exit are investigated, and the result indicates that cutting CFRP in the upward direction has positive effects on deflection limitation and damage reduction. In order to perform the upward cutting, a novel intermittent-sawtooth drill structure is proposed on the one-shot drill. The theoretical and geometrical analyses of the drilling process reveal that the cutting lips of the structure could reverse the cutting direction from downward to upward and thereby, reduce the drill-exit damages. Furthermore, drilling experiments are conducted and the drill structure is proved to be effective to reduce drilling damages as expected.


      PubDate: 2016-08-23T08:35:00Z
       
  • Tool deflection model and profile error control in helix path contour
           grinding
    • Abstract: Publication date: Available online 18 August 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Yanglin Peng, Yifan Dai, Ci Song, Feng Shi
      Because of finite stiffness of grinding system, grinding force will cause the tool deflection (the difference between actual cutting depth and nominal cutting depth). During helix path contour grinding, the grinding condition are variable at different grinding point which will bring forward different tool deflection and result in dimensional errors. This paper presents an error analysis model during multi-pass grinding, which can predict the accumulation process of surface profile error induced by tool deflection. It establishes the relationship between profile error and grinding parameters. The estimation method of key model parameters is described in the proposed model through series of experiments. According to the error analysis model, we can implement the varied feed rate and varied cutting depth method for compensating the profile error. The grinding experimentation and compensation grinding verifies the validity of error analysis model and effectiveness of compensation method, and the profile error reduced by 82.1% comparing with grinding process without compensation.


      PubDate: 2016-08-23T08:35:00Z
       
  • From the microscopic interaction mechanism to the grinding temperature
           field: An integrated modelling on the grinding process
    • Abstract: Publication date: Available online 17 August 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jingliang Jiang, Ge Peiqi, Shufeng Sun, Dexiang Wang, Yuling Wang, Yong Yang
      The microscopic interaction mechanism between grains and workpiece material in grinding contact zone is extremely complicated which will take many interrelated and coupled factors into consideration, such as grinding wheel topographies, grain distributions, physical and mechanical properties of material, the emergence of grinding forces and heat energies, the partitioning and transfer of grinding heat, etc. However, the current theories and models are unable to integrate all of the above factors into an organic-whole model. Former researchers usually focused on several of above aspects and made assumptions to simplify those theories. However, these assumptions will weaken the mathematical relationship between grinding conditions and ground surface qualities and will increase the difficulties of understanding on the nature of grinding process. The work of this paper is an attempt on this purpose. It is based on the author's previous work of a microscopic interaction mechanism model between grains and workpiece material in grinding contact zone which will describe the interaction situation of a grain with any size, protrusion height and location, then the distributions of each type of grains were obtained. Single plowing and cutting grain force models were developed based on R.L. Hecker's single grain force model and M.E. Merchant's metal cutting theory, then led into grinding force distribution. The heat partition ratio model of W.B. Rowe was applied on the discrete grinding contact zone, a new developed heat flux profile transferred into workpiece surface was obtained, which was usually assumed to be rectangular, triangular and parabolic in shape in former researches. In order to confirm the rationality of this new heat flux profile, a comparison on temperature fields and grinding forces has been made between results from FE-models and experiments, under both wet and dry grinding conditions. Comparison results showed that this new developed integrated grinding process model has more precise prediction ability on grinding forces and grinding temperatures.


      PubDate: 2016-08-17T20:55:41Z
       
  • Prediction of Rounding Phenomenon at Corner Tips in Large-area Electron
           Beam Irradiation
    • Abstract: Publication date: Available online 11 August 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Togo Shinonaga, Akira Okada, Tomoaki Miyoshi
      In large-area electron beam (EB) irradiation method, corner tip of workpiece is generally rounded since removal of material at the tip is done preferentially. Investigation of the shape change is necessary to clarify rounding phenomenon with irradiation of EB. In this study, the shape changes of corner tips were experimentally investigated by Scanning Electron Microscope (SEM) observation of the cross sections. Then, electron track analysis in the EB irradiation was conducted to clarify an electron concentration at the tip. Unsteady heat conduction analysis at the tip was also done with considering the EB concentration at the tip and an electron penetration effect into the surface. The shape changes were estimated by simulation of temperature distribution at the tips. Experimental results show that the curvature radius increases with shot number of EB. The estimated shape changes show quantitatively good agreement with the experimental ones. These results indicate that the rounding phenomenon at the tips by large-area EB irradiation can be predicted by our electron track and unsteady heat conduction analysis model.


      PubDate: 2016-08-13T20:32:40Z
       
  • Investigation on a new hole-flanging approach by incremental sheet forming
           through a featured tool
    • Abstract: Publication date: Available online 9 August 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Tingting Cao, Bin Lu, Hengan Ou, Hui Long, Jun Chen
      One of the major challenges in conventional incremental sheet forming (ISF) is the extreme sheet thinning resulted in an uneven thickness distribution of formed part. This is also the case for incrementally formed parts with hole-flanging features. To overcome this problem, a new ISF based hole-flanging processing method is proposed by developing a new ISF flanging tool. Comparative studies are conducted by performing hole-flanging tests using both ISF conventional ball-nose tool and the new flanging tool to evaluate the sheet deformation behavior and the quality of the final part. Stress distribution and strain variation are investigated by analytical approach and numerical simulation. Experiments have been conducted to validate the analytical model and simulation results, and to further study the fracture behavior. Results show that the new flanging tool generates greater meridional bending than stretching deformation in conventional ISF. The combination of bending-dominated deformation mode with localized deformation of ISF ensures more uniform thickness distribution on hole-flanging part with better resistance to fracture.


      PubDate: 2016-08-13T20:32:40Z
       
  • Chip Formation and Microstructure Evolution in the Adiabatic Shear Band
           When Machining Titanium Metal Matrix Composites
    • Abstract: Publication date: Available online 3 August 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Roland Bejjani, Marek Balazinski, Helmi Attia, Philip Plamondon, Gilles L’Éspérance
      Titanium Metal Matrix Composite (Ti-MMC) is a relatively new class of material, which has high potential applications in the aeronautical and biomedical sectors. Similar to titanium alloys, Ti-MMC produces segmented chips, which are characterized by Adiabatic Shear Bands (ASB). Transmission Electron Microscopy (TEM) observations were performed and dislocations were observed on the atomic scale. Furthermore, the sheared surfaces, as well as the effects of the hard TiC particles on the ASB formation were investigated. It was shown that the grains located in the lightly strained areas within the chip segment are characterized by a high dislocation density. This is contrary to the highly strained areas inside the ASB, where the temperature was estimated to be close to the recrystallization temperature. Analysis of the results showed that no phase transformation took place inside the ASB. The strain and strain rate in the ASB were estimated to reach 7.5 and 4.5x105 s−1, respectively. Using TEM and Focused Ion Beam (FIB) for sample preparation, the microstructure inside the ASB was found to be composed of elongated and equiaxed nano-sized grains. The segmentation mechanism of chips was observed to start from a crack on the material free surface ahead of the tool, and not at the tool tip. Furthermore, the hard particles inside the matrix were found not to be hindering, or retarding the ASB formation. A microstructural evolution model, based on these observations, has also been proposed. To the authors’ best knowledge, TEM studies of ASB for Ti-MMC were never done previously for machining applications.


      PubDate: 2016-08-04T20:04:32Z
       
  • A review of geometrical and microstructural size effects in micro-scale
           deformation processing of metallic alloy components
    • Abstract: Publication date: Available online 28 July 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): M.W. Fu, J.L. Wang, A.M. Korsunsky
      Plastic deformation at the macroscopic scale has been widely exploited in industrial practice in order to obtain desired shape and control the requested properties of metallic alloy parts and components. The knowledge of deformation mechanics involved in various forming processes has been systematically advanced over at least two centuries, and is now well established and widely used in manufacturing. However, the situation is different when the physical size of the workpiece is scaled down to the micro-scale (µ-scale). In such cases the data, information and insights from the macro-scale (m-scale) deformation mechanics are no longer entirely valid and fully relevant to µ-scale deformation behavior. One important reason for the observed deviation from m-scale rules is the ubiquitous phenomenon of Size Effect (SE). It has been found that the geometrical size of workpiece, the microstructural length scale of deforming materials and their interaction significantly affect the deformation response of µ-scale objects. This observation gives rise to a great deal of research interest in academia and industry, causing significant recent effort directed at exploring the range of related phenomena. The present paper summarizes the current state-of-the-art in understanding the geometrical and microstructural SEs and their interaction in deformation processing of µ-scale components. The geometrical and grain SEs in µ-scale deformation are identified and articulated, the manifestations of the SE are illustrated and the affected phenomena are enumerated, with particular attention devoted to pointing out the differences from those in the corresponding m-scale domain. We elaborate further the description of the physical mechanisms underlying the phenomena of interest, viz., SE-affected deformation behavior and phenomena, and the currently available explanations and modeling approaches are reviewed and discussed. Not only do the SEs and their interaction affect the deformation-related phenomena, but they also induce considerable scatter in properties and process performance measures, which in turn affects the repeatability and reliability of deformation processing. This important issue has become a bottleneck to the more widespread application of µ-scale deformation processing for mass production of µ-scale parts. What emerges is a panoramic view of the SE and related phenomena in µ-scale deformation processing. Furthermore, thereby the outstanding issues are identified to be addressed to benefit and promote practical applications.
      Graphical abstract image

      PubDate: 2016-07-29T19:41:48Z
       
  • Relationship between temperature at cut front edge and kerf quality in
           fiber laser cutting of Al–Cu aluminum alloy
    • Abstract: Publication date: October 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 109
      Author(s): Cong Chen, Ming Gao, Xiaoyan Zeng
      The characteristics of the temperature at cut front edge (Tce ) during fiber laser cutting of AA2219 aluminum alloy were studied. A temperature monitoring system employing an infrared laser thermometer was established to record the time-domain T ce . A series of experiments was carried out to explore the relationship between the T ce and kerf quality. There was an optimal T ce range of 1800–1950°C for accepted kerf. By calculating the forces acting on molten pool, the existence of the optimal T ce range was demonstrated, and the effect of the T ce on kerf quality was discussed. The kerf quality was mostly dependent on the angle of the resultant to the downward (θ). Only when the θ was around the minimum of 38° that is corresponding to optimal T ce range, the kerf was accepted because the liquid metal was pushed away smoothly, although the resultant value was small. When increasing or decreasing the T ce outside the optimal range, the kerf was bad because the increased θ intended to push the liquid metal backward to attach on the kerf rather than push them away.


      PubDate: 2016-07-29T19:41:48Z
       
  • Influenceof hatch spacing on heat and mass transfer, thermodynamics and
           laser processability during additive manufacturing of Inconel 718 alloy
    • Abstract: Publication date: Available online 27 July 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Mujian Xia, Dongdong Gu, Guanqun Yu, Donghua Dai, Hongyu Chen, Qimin Shi
      Atransient three-dimensional powder-scale model has been established for investigating the thermodynamics, heat and mass transfer and surface quality within the molten pool during selective laser melting (SLM) Inconel 718 alloy by finite volume method (FVM), considering the powder-solid transition, variation of thermo-physical properties, and surface tension. The influences of hatch spacing (H) on the thermodynamics, heat and mass transfer, and resultant surface quality of molten pool have been discussed in detail. The results revealed that the H had a significant influence on determining the terminally solidified surface quality of the SLM-processed components. As a relative lower H of 40μm was used, a considerable amount of molten liquid migrated towards the previous as-fabricated tracks with a higher velocity, resulting in a stacking of molten liquid and the attendant formation of a poor surface quality with a large average surface roughness of 12.72μm. As an appropriate H of 60μm was settled, a reasonable temperature gradient and the resultant surface tension tended to spread the molten liquid with a steady velocity, favoring the formation of a flat surface of the component and an attendant low average surface roughness of 2.23μm. Both the surface morphologies and average surface roughness were experimentally obtained, which were in a full accordance with the results calculated by simulation.


      PubDate: 2016-07-29T19:41:48Z
       
  • A predictive model of grinding force in silicon wafer self-rotating
           grinding
    • Abstract: Publication date: Available online 27 July 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jinglong Sun, Fei Qin, Pei Chen, Tong An
      Silicon wafer thinning is mostly performed by the method of self-rotating grinding. In grinding, the grinding force is a crucial factor of affecting the grinding performance, form accuracy and surface/subsurface thinning quality. To control the thinning quality of ground wafer, grinding force is the most essential factor need to be controlled. However, no theoretical model is developed to correlate grinding parameters to grinding force yet. In this article, a theoretical model is established based on the removal behavior of silicon, including cutting and sliding. For the first time, the effects of processing parameters, wafer radial distance and crystal orientation on grinding force are quantitatively described in a theoretical model. Excess grinding force causes local damage of wafer in the form of subsurface cracks, as a determinant factor on the quality of wafer. Therefore, nine sets of self-rotating grinding experiments with variable processing parameters are performed, and the depth of subsurface cracks h are measured to evaluate the damage of ground wafer. Based on the scratching theory of single abrasive grain, the relationship between h and the normal grinding force F nt is found, which is also validated by the experimental results. Finally, an optimized two-stage process is proposed to control subsurface cracks and improve material removal rate simultaneously, according to the predictive model of grinding force.


      PubDate: 2016-07-29T19:41:48Z
       
  • Studyon a 5-axis precision and mirror grinding of glass freeform surface
           without on-machine wheel-profile truing
    • Abstract: Publication date: Available online 27 July 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): J Xie, Z J Deng, J Y Liao, N Li, H Zhou, W X Ban
      Theprecision freeform grinding depends on the on-machine truing of diamond wheel, leading to the inefficiency of grinding system. Hence, a virtual ball-end algorithm along with a fixed tool posture angle is proposed for the 5-axis grinding of glass by using a self-dressing diamond wheel. The objective is to realize the precision and mirror freeform grinding without any wheel-profile truing. First, virtual ball-end grinding, ground freeform surface and freeform errors compensation were modeled in 5-axis grinding system, respectively; then tool interference, envelope trace height, grain cutting depth and ground surface roughness were systemically investigated in connection with tool posture angle, tool sizes, grain protrusion variables, abrasive parameters and self-dressing coefficient; finally, the 5-axis grinding experiments of F-theta freeform glass lens were performed. It is shown that the virtual ball-end algorithm is valid for the 5-axis freeform grinding with a self-dressing abrasive tool. Increasing tool posture angle decreases the grain cutting depth to the critical cutting depth from brittle cutting to ductile cutting, but it increases the risk of tool interference. The mirror freeform grinding may be parameterized by material behavior, tool size and posture, grinding conditions and abrasive tool performance. On the base of virtual ball-end algorithm, the form errors compensation enhances the mirror-ground freeform accuracy by 26%. It is confirmed that the 3-μm-size diamond grinding without on-machine truing is feasible to fabricate the precision and mirror freeform glass along with the tool posture angle of 30°.
      Graphical abstract image

      PubDate: 2016-07-29T19:41:48Z
       
  • IFC - Editorial board
    • Abstract: Publication date: September 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 108




      PubDate: 2016-07-25T11:48:25Z
       
  • Crack-free ductile mode grinding of fused silica under controllable dry
           grinding conditions
    • Abstract: Publication date: Available online 21 July 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Wei Wang, Peng Yao, Jun Wang, Chuanzhen Huang, Hongtao Zhu, Bin Zou, Hanlian Liu, Jiwang Yan
      A crack-free ductile mode grinding of fused silica was realized by a controllable dry grinding process in this research, which is attributed to the improvement of fused silica's ductile machinability induced by the high grinding temperature. The plastic deformation of fused silica consists of shear flow and densification. Plastic deformation mechanisms and cracking behaviors related to densification were investigated firstly by high temperature nanoindentation experiments to reveal the ductile-brittle transition mechanisms. Fused silica exhibits less densification and more shear flow at high temperature than room temperature. The critical ductile-brittle transition load of fused silica is lower at high temperature than room temperature. These results may lead to the improvement of the fused silica's ductile machinability at high temperature. Dry grinding experiments were conducted to investigate the effect of grinding depth. A mathematical model is established to predict the maximum temperature in workpiece. A novel infrared radiation (IR) transmission on-line measurement method was presented to acquire the workpiece temperature in the contact zone directly. The predicted results coincide well with the experiment results. Contrary to the conventional experience, a large grinding depth is beneficial for the surface quality and integrity in the dry grinding of fused silica due to the increased grinding temperature; however, the excessive grinding depth results in grinding wheel burn. The ductile grinding depth of the fused silica increases from sub-micrometers to 5μm by dry grinding which makes the grinding process more controllable and effective.


      PubDate: 2016-07-25T11:48:25Z
       
  • Pulsed ultrasonic assisted electrical discharge machining for finishing
           operations
    • Abstract: Publication date: Available online 15 July 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): M. Goiogana, J.A. Sarasua, J.M. Ramos, L. Echavarri, I. Cascón
      Electrical Discharge Machining (EDM) is a non-conventional machining process specially suitable for manufacturing hard-to-machine materials or geometrically complex parts. Many investigations have been presented combining EDM with ultrasonic (US) vibration of the electrode, but most of them have been intended to enhance the material removal rate of the process. In this paper US assisted EDM process has been used in order to improve the surface roughness in a finishing operation. For that purpose a copper rod tool electrode and a 1.2344 tempered alloy steel workpiece have been used. A pulsed US assisted EDM mode (PUEDM) has been developed and compared with the current EDM process and EDM assisted with continuous US vibration (UEDM). The results show that PUEDM process can improve the surface roughness and homogeneity of the machined surfaces in finishing EDM operations.


      PubDate: 2016-07-18T11:38:26Z
       
  • Textured grinding wheels: A review
    • Abstract: Publication date: Available online 6 July 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Hao Nan Li, Dragos Axinte
      Textured grinding wheels (TGWs) are wheels that have both specially-designed active and passive grinding areas on their geometrically active surfaces. The active area allows TGWs to perform the intermittent grinding process such that total wheel-workpiece contact time, average grinding forces and temperature in the cutting zone can be reduced. The passive area (or textures) refers to the non-grinding area where no grain is located at and the main functions of it include serving as reservoirs to transport more coolants/lubricants into the grinding zone and providing larger chip disposal space. With the increasingly demanding requirements from industries, the continuous evolution of TGWs has been enforced. However, to the best of the authors’ knowledge, no comprehensive review on TGWs has been reported yet. To address this gap in the literature, this paper aims to present an informative literature survey of research and engineering developments in relation to TGWs, define and categorise TGW concepts, explain basic principles, briefly review the concept developments, discuss key challenges, and further provide new insights into understanding of TGWs for their advanced future engineering applications.


      PubDate: 2016-07-09T14:28:48Z
       
  • Chatter Prediction for the Peripheral Milling of Thin-walled Workpieces
           with Curved Surfaces
    • Abstract: Publication date: Available online 5 July 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Yun Yang, Wei-Hong Zhang, Ying-Chao Ma, Min Wan
      Workpiece dynamics is the dominant factor which should be taken into consideration in chatter prediction of peripheral milling of thin-walled workpieces. Usually, material removal, tool position and varying dynamic displacements of the workpiece along the tool axis influence the workpiece dynamics. However, these three aspects were not considered simultaneously in the existing researches. This paper comprehensively investigates the effect of varying workpiece dynamics on the stability in peripheral milling of thin-walled workpieces with curved surfaces. A new dynamic model of tool and workpiece system is proposed to consider the dynamic behavior of tool and workpiece as well as the influences of engagement and tool feed direction. Interaction between tool and thin-walled workpiece is modeled at discrete nodes along the axial depth of cut. An efficient method based on structural dynamic modification scheme is developed to characterize the effect of material removal upon the in-process workpiece dynamics. This is done by only performing modal analysis on the FEM model of initial workpiece, while mode shapes and natural frequencies of the in-process workpiece can be calculated without re-building and re-meshing the instant FEM model at each tool position. The proposed model and method are verified by the milling process of two thin-walled workpieces concerning a plate and a workpiece with curved surface. Comparisons of numerical and experimental results show that chatter can be accurately predicted for the peripheral milling of thin-walled workpieces.


      PubDate: 2016-07-09T14:28:48Z
       
  • Discrete-element modelling of the grinding contact length combining the
           wheel-body structure and the surface-topography models
    • Abstract: Publication date: Available online 6 July 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): J.L. Osa, J.A. Sánchez, N. Ortega, I. Iordanoff, J.L. Charles
      Phenomena governing the grinding process are largely related to the nature and evolution of contact between grinding wheel and ground component. The definition of the contact area plays an essential role in the simulation of grinding temperatures, forces or wear. This paper presents a numerical model that simulates the contact between grinding wheel and workpiece in surface grinding. The model reproduces the granular structure of the grinding wheel by means of the discrete element method. The surface topography is applied on the model surface taking into account the dressing mechanisms and movements of a single-point dresser. The individual contacts between abrasive grits and workpiece are studied regarding the uncut chip thickness, assuming viscoplastic material behaviour. Simulation results are evaluated with experimental measurements of the contact length. The results remark the importance of surface topography and dressing conditions on the contact area, as well as wheel deflection.


      PubDate: 2016-07-09T14:28:48Z
       
  • Performance and modeling of Paired polishing process
    • Abstract: Publication date: Available online 7 July 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Tianyu Yu, David T. Asplund, Ashraf F. Bastawros, Abhijit Chandra
      Paired polishing process (PPP) is a variant of the chemical mechanical polishing process which facilitates defect mitigation via minimization of maximum force as well as effective planarization via profile driven determination of force gradient. The present embodiment of PPP machine employs two polishing wheels, radially spanning the wafer surface on a counter-gimbaled base. The PPP machine is deployed to experimentally investigate the role of the process parameters on the surface roughness evolution, and the effective material removal rate. Two sets of copper and aluminum blanket layers were polished under a range of applied down force, polishing wheel speed and transverse feed rate to examine the scalability of the process parameters for different material constants. The experimental measurements along with the topological details of the polishing pad have been utilized to develop a mechanistic model of the process. The model employs the soft wheel-workpiece macroscopic contact, the polishing wheel roughness and its amplification to the local contact pressure, the kinematics of abrasive grits at the local scale, and the collective contribution of these individual micro-events to induce an effective material removal rate at the macroscale. The model shows the dependence of the material removal on the ratio of wheel rotational to feed speed for the PPP process, in a form of an asymptote that is scaled by the surface hardness of each material. The PPP machine exploits this insight and utilizes an oblique grinding technique that obviates the traditional trade-off between MRR and planarization efficiency.


      PubDate: 2016-07-09T14:28:48Z
       
  • Predicting mobile machine tool dynamics by experimental dynamic
           substructuring
    • Abstract: Publication date: Available online 22 June 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Mohit Law, Hendrik Rentzsch, Steffen Ihlenfeldt
      Predicting mobile machine tool dynamics prior to moving the machine to a new part and/or location is essential to guide first-time-right in situ machining solutions. This paper considers such a priori prediction of assembled dynamics under varying base/part/contact characteristics by applying dynamic substructuring procedures. Assembled dynamics are predicted by substructural coupling of the machine's known free-free response with the known response of any base/part measured at location. Since obtaining the machine's free-free response remains non-trivial, we instead extract the machine's dynamics using substructure decoupling procedures. Substructuring is carried out using measured frequency response functions. Methods are tested for robustness, and are experimentally validated.


      PubDate: 2016-06-26T17:37:50Z
       
  • Evolution and equivalent control law of surface roughness in
           shear-thickening polishing
    • Abstract: Publication date: Available online 23 June 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Min Li, Binghai Lyu, Julong Yuan, Weifeng Yao, Fenfen Zhou, Meipeng Zhong
      A comprehensive surface roughness model is established to predict the average surface roughness achieved by shear-thickening polishing (STP) based on calculation of Brinell hardness number (BHN), shear-thickening mechanism and plastic indentation on abrasive wear theory. The model takes the effects of material hardness and plastic wear into account in addition to the calculation of the surface roughness factors concerning the normal pressure, slurry performance, et al. The “size effect” as the ratio of abrasive size to solid colloidal particle size, has also been successfully integrated into the model. STP experiments validate that the maximal difference of surface roughness between theoretical and experimental results is no greater than 12.02%. The surface evolution process can be theoretically and experimentally described with certain feasibility and veracity. An inflection point appears in the trend line of predicted surface roughness when the ratio approaches to 0.5. An equivalent control law of surface roughness in STP exists when the ratio is greater than 0.5 and is revealed by the model and experiments due to the competing effects of kinematics, indentation depth, cutting width, plastic plowing of materials on surface formation. The freedom control for an invariable surface roughness can be achieved by STP according to the equivalent control law. The prediction model for brittle materials shall be revised based on material properties and more removal forms.


      PubDate: 2016-06-26T17:37:50Z
       
  • Cutting force prediction for ultra-precision diamond turning by
           considering the effect of tool edge radius
    • Abstract: Publication date: Available online 23 June 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): P. Huang, W.B. Lee
      Many studies have been conducted to develop algorithms for cutting force prediction in a variety of machining process. However, few studies have developed the cutting force prediction algorithm by considering the effect of tool edge radius in ultra-precision diamond turning, including fast tool servo/slow tool servo assisted diamond turning. This paper presents a cutting force prediction algorithm for the ultra-precision diamond turning, which is able to take into account the effect of tool edge radius. The developed algorithm is general for predicting cutting force in most cylindrical diamond turning processes such as fast tool servo/ slow tool servo assisted diamond turning. Experiments are conducted to validate the cutting force prediction algorithm. The experimental results verify the assumed relationship between the chip formation and the minimum chip thickness, where the work material is entirely removed when the uncut chip thickness is larger than a certain value. The estimated value of minimum chip thickness is obtained. The measured cutting force shows good agreement with the simulated value. In addition, the friction induced vibration due to elastic recovery occurs when a worn diamond cutting tool is adopted in the experiment.


      PubDate: 2016-06-26T17:37:50Z
       
  • The effects of dub-off angle on chip evacuation in single-lip deep hole
           gun drilling
    • Abstract: Publication date: Available online 28 May 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): G.L. Tnay, S. Wan, K.S. Woon, S.H. Yeo
      Without proper chip evacuation, gun drills will fail under intense thermal and mechanical loading during deep hole drilling of high temperature superalloys like Inconel 718. In gundrilling, the efficiency in evacuating chips is governed by the geometry of gun drills that defines the hydraulic boundary conditions for coolant and chip flow. In this paper, we propose a novel computational fluid dynamics (CFD) model that is capable to simulate and quantify the chip transportation behavior under high pressure coolant for drill geometry optimization. This is demonstrated through a case study on improving the shoulder dub-off design of commercial gun drills, which have a high tendency in trapping chips at the hole bottom. A more effective design criterion for the shoulder dub-off is thus proposed.


      PubDate: 2016-06-16T18:04:30Z
       
  • Dual Sliding Mode Contouring Control with High Accuracy Contour Error
           Estimation for Five-axis CNC Machine Tools
    • Abstract: Publication date: Available online 1 June 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Xiangfei Li, Huan Zhao, Xin Zhao, Han Ding
      Five-axis CNC machine tools are widely used in the manufacturing of the complex parts, and the contour error is the key indicator for the accuracy of the final product. Contour error, by definition, is a geometrical quantity solely dependent on the current actual tool pose and the reference trajectory. Contouring control is the main method to reduce or eliminate it. In this paper, based on the geometrical information of the reference trajectory, a high accuracy contour error estimation method for five-axis machine tools is proposed. Then, to avoid the time-consuming calculation of the inverse and derivative of the Jacobian matrix, to reduce tracking and contour errors simultaneously as well as suppress the chattering in the control signal, a dual sliding mode contouring control method is proposed. The dual sliding surface is selected for each drive separately, which integrates the traditional PD-type tracking sliding surface, a PD-type contouring sliding surface consisting of the axis component of the contour errors, and the input signal together. Experiments are conducted on a tilting-rotary-table type five-axis CNC machine tool. The results demonstrate that the contour errors estimated using the proposed method are very close to the true ones, and compared with the traditional sliding mode controller, the proposed method can reduce the contour error and the chattering behavior effectively.


      PubDate: 2016-06-16T18:04:30Z
       
  • Chatter detection in milling process based on the energy entropy of VMD
           and WPD
    • Abstract: Publication date: Available online 8 June 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhao Zhang, Hongguang Li, Guang Meng, Xiaotong Tu, Changming Cheng
      This paper presents a novel approach to detect the milling chatter based on energy entropy. By using variational mode decomposition and wavelet packet decomposition, the cutting force signal is decomposed into two group of sub-signals respectively, and each component has limited bandwidth in spectral domain. Since milling chatter is characterized by the change of frequency and energy distribution. Therefore the energy features extracted from the two group of sub-signals are considered and the energy entropies are obtained, which can be utilized to demonstrate the condition of the milling system synthetically. Several milling tests are conducted and the results show that the proposed method can effectively detect the chatter at an early stage.


      PubDate: 2016-06-16T18:04:30Z
       
  • Experimental studies and CFD simulation of the internal cooling conditions
           when drilling Inconel 718
    • Abstract: Publication date: Available online 8 June 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Ekrem Oezkaya, Nicolas Beer, Dirk Biermann
      When drilling the superalloy Inconel 718 twist drills are faced with high thermomechanical loads. Owing to the low thermal conductivity of the workpiece material a large amount of the generated heat has to be transported away from the tool by the coolant. In this paper, the influence of the coolant pressure and the diameter of the coolant channels have been studied. The experiments have been supported by using computational fluid dynamics (CFD) simulations and were focused on the tool wear and the bore quality. The CFD simulation is a valuable tool which supported the present investigation, that a higher mass flux has no advantage regarding tool life and bore quality; moreover, the modification of the channel diameters has not reduced the thermal loads. In all investigated processes, dead zones near the cutting edge and the counter edge could not be reduced by increasing the flow rate. Only by the use of higher coolant pressures, the tool life could be significantly increased, as well as the bore quality. The investigations prove that especially when metrological methods reach their limits, the CFD is a suitable tool; which supports the design process effectively by giving a better insight into the coolant flow resulting from the complex drilling processes.


      PubDate: 2016-06-16T18:04:30Z
       
  • Sphere forming mechanisms in vibration-assisted ball centreless grinding
    • Abstract: Publication date: Available online 16 June 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Weixing Xu, Dandan Cui, Yongbo Wu
      This paper aims to clarify the sphere forming mechanisms in vibration-assisted ball centreless grinding, a new technique for effectively processing balls using ultrasonic vibrations. Based on a comprehensive analysis of the ball rotation motion, geometrical arrangement and stiffness of the whole grinding system, a reliable mechanics model was successfully developed for predicting the sphere forming process. Relevant experiments conducted showed that the model had captured the mechanics and the major sphere forming mechanisms in ball centreless grinding. It was found that the ball whole surface can be well ground with a high accuracy, while efficiency is much enhanced compared with that in the traditional methods. The ball rotational speed which is controlled by the ultrasonic regulator has a great impact on final sphericity, and the speed controlled by the ultrasonic shoe dominates the whole processing time. To achieve a stable and high precision grinding, the ball needs to rotate rhythmically, and the wheel feed per step and the ball location angle should be controlled in a critical range.


      PubDate: 2016-06-16T18:04:30Z
       
  • Contouring control for three-axis machine tools based on nonlinear
           friction compensation for lead screws
    • Abstract: Publication date: Available online 11 June 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Ba Dinh Bui, Naoki Uchiyama, Kenneth Renny Simba
      Friction is the main disturbance in mechanical systems especially in computerized numerical control machine tools with high precision, speed, and performance requirements. Much recent research have proven that a controller with friction compensation provides better performance. Some classical friction models such as the Coulomb-viscous-Stribeck friction model, the Lugre model, and the Generalized Maxwell Slip (GMS) model have been proposed to compensate for frictional effects to reduce the contour error and to improve the surface quality. However, most of the conventional friction models focus on frictional properties in pre-sliding regime and low velocity sliding regime. These models do not fully describe and compensate for friction in machine tool systems in case of high speed motion or insufficient lubrication. This paper presents a new friction model that combines the conventional Coulomb-viscous friction model and a nonlinear sinusoidal component for fully describing the friction behaviour of feed drive systems. In addition, this study presents controller design with feed forward compensation based on the proposed friction model. Experiments were conducted to compare the control performance between the proposed and the conventional friction models. Experimental results indicate that the mean contour error has been significantly reduced by 26% after applying the proposed controller.


      PubDate: 2016-06-16T18:04:30Z
       
  • Effect of friction at chip–tool interface on chip geometry and chip
           snarling in tapping process
    • Abstract: Publication date: August 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 107
      Author(s): Yasuyoshi Saito, Shoki Takiguchi, Takeshi Yamaguchi, Kei Shibata, Takeshi Kubo, Wataru Watanabe, Satoru Oyama, Kazuo Hokkirigawa
      During tapping processes, the chip snarling problem must be resolved to improve manufacturing efficiency. In this study, we used an electroless plating method to develop a tapping tool coated with Ni−P/abrasive-particle composite film to solve the chip snarling problem. The tapping test was conducted at 10m/min (conventional cutting velocity) and 50m/min with a machining center. The cutting torque and thrust force were measured using a dynamometer. The results of the tapping test indicate that the developed tapping tool coated with the composite film prevented chip snarling at 10m/min and 50m/min. The dimensionless diameter for the developed tapping tool, which is the diameter of the chip curl divided by the width of the helical flute, was less than 1.0 for both cutting conditions, whereas that for steam-treatment and TiCN film is greater than 1.0. Furthermore, we estimated the coefficient of friction between the rake face of the cutting edge of the tapping tool and the chip from the thrust force and cutting torque. The estimated coefficient of friction for the tapping tool coated with the composite film (>1.23) was greater than that for the other methods (<1.23). These results indicate that a high coefficient of friction (>1.23) is necessary to prevent chip snarling, and due to the high coefficient of friction, the developed tapping tool can prevent chip snarling even at a speed of 50m/min.


      PubDate: 2016-06-16T18:04:30Z
       
  • Kinematic corner smoothing for high speed machine tools
    • Abstract: Publication date: September 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 108
      Author(s): Shingo Tajima, Burak Sencer
      This paper presents a novel kinematic corner smoothing technique for high-speed CNC machine tools. Typically, reference tool-paths compromised of short G01 moves are geometrically smoothed by means of arcs and splines within the NC system. In this study, a continuous feed motion is generated by directly planning jerk limited velocity transitions for the drives in the vicinity of sharp corners of the tool-path. This approach completely eliminates the need for geometry based path smoothing and feed planning. Contouring errors at sharp corners are controlled analytically by accurately calculating cornering speed and duration. Since proposed approach bases on kinematically planning axis motion profiles, it exploits acceleration and jerk limits of the drives and delivers a near-time optimal motion. Experimental validation and comparisons are presented to show significant improvement in the cycle time and accuracy of contouring Cartesian tool-paths.


      PubDate: 2016-06-16T18:04:30Z
       
  • IFC - Editorial board
    • Abstract: Publication date: August 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 107




      PubDate: 2016-06-16T18:04:30Z
       
  • A thermo-electro-mechanical simulation model for hot wire cutting of EPS
           foam
    • Abstract: Publication date: August 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 107
      Author(s): Kiril P. Petkov, Jesper H. Hattel
      A one-dimensional thermo-electro-mechanical mathematical model describing the effects taking place within a Ni–Cr20% wire used in a hot-wire cutting process for free forming and rapid prototyping of expanded polystyrene (EPS) is investigated and simulated. The model implements and solves three semi-coupled non-linear differential equations (the heat diffusion equation, the electrical diffusion equation and the static equilibrium equation) with temperature dependent parameters in order to predict the temperature, kerfwidth, longitudinal stress and displacement, and other process parameters during cutting of EPS in contact with a cutting tool made of an electrically heated metal wire attached to a robot device. The finite difference method is used to solve the coupled equations in the two environments (domains) in which the hot-wire operates, namely air and EPS. The model is calibrated against experimentally obtained data. Novel findings are a transient temperature-dependent kerfwidth prediction and a relation between kerfwidth and the cutting angle as measured from the horizontal direction. These are important relations in the aim for higher geometrical accuracy of the hot-wire cutting process.


      PubDate: 2016-06-16T18:04:30Z
       
  • Modeling and simulation of the high-speed milling of hardened steel SKD11
           (62 HRC) based on SHPB technology
    • Abstract: Publication date: September 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 108
      Author(s): Chengyong Wang, Feng Ding, Dewen Tang, Lijuan Zheng, Suyang Li, Yingxing Xie
      An easy-to-produce sawtooth chip is the main feature of the high-speed milling of hardened steel. In previous works, a theoretical geometric model was proposed for the sawtooth chip formation to predict the strain and strain rate in the shear band during chip formation; these properties are important when describing the deformation characteristics for the cutting of hardened steel materials. In the cutting process, however, the changes and distributions of stress and strain can hardly be obtained using a theoretical model. This paper modifies the conventional empirical Johnson–Cook constitutive equation by employing stress–strain curves at high temperature and a high strain rate obtained using split Hopkinson pressure bar technology and considering the negative strain rate effect and temperature effect of the material, especially for SKD11 (62 HRC) hardened steel. A thermo-mechanical coupled two-dimensional planar strain finite element model for the high-speed milling of SKD11 hardened steel with a modified Johnson–Cook constitutive equation is presented. The geometric characteristics of chip formation during the high-speed milling of SKD11 are predicted and the results are in good agreement with experimental results. Employing the modified finite element model, the stress and strain in the shear band during high-speed cutting are quantitatively analyzed and found to be in close agreement with the results of a theoretical model analysis. It is found that the cutting speed has a critical value at which the stress and strain reach a certain value and the distributions of stress and strain change in the shear band, resulting in the generation of a sawtooth chip. Moreover, the cutting force, cutting temperature, and selection of a coated tool are discussed according to results obtained with the modified finite element model. The cutting force and difference in temperature decrease while the temperature increases as the cutting speed increases. Compared with a TiAlN-coated tool, a TiSiN-coated tool performs better in cutting SKD11 hardened steel in terms of the cutting temperature.


      PubDate: 2016-06-16T18:04:30Z
       
  • Improving machined surface texture in avoiding five-axis singularity with
           the acceptable-texture orientation region concept
    • Abstract: Publication date: September 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 108
      Author(s): Zhiwei Lin, Jianzhong Fu, Hongyao Shen, Guanhua Xu, Yangfan Sun
      The singular phenomenon is common in five-axis machining process. Most of the existing methods try to solve the problem by deforming the tool orientations or inserting extra cutter locations after the tool path is generated, with the drawbacks that (1) the machining geometry errors are not respected and (2) irregular machined surface textures might be caused. This paper dedicates to improve the machined surface textures in the scenario of avoiding the five-axis singularities. In this paper, the acceptable-texture orientation region (ATOR) concept is proposed. If the tool orientation is picked inside the ATOR, the resulted surface texture is considered to be acceptable. Based on this concept, the tool orientations are optimized locally. For a given tool path, if the orientation curve crosses the singular circle, it is locally modified out of the circle with a bridge point locating schema and a cubic B-spline interpolation technique. Eventually, the obtained new orientation curve goes around the singular circle like a rubber band to avoid the singular problem and remains unmodified to achieve the best machined surface qualities for the rest pieces. As the process is implemented at the tool path planning stage, the machining geometry errors can also be respected.


      PubDate: 2016-06-16T18:04:30Z
       
  • IFC - Editorial board
    • Abstract: Publication date: July 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 106




      PubDate: 2016-05-13T16:40:14Z
       
  • Suppression of the time-varying vibration of ball screws induced from the
           continuous movement of the nut using multiple tuned mass dampers
    • Abstract: Publication date: Available online 13 May 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Min Wang, Tao Zan, Xiangsheng Gao, Songwei Li
      Considering the time-varying vibration characteristics of the ball screw caused by the continuous movement of the nut, this paper takes the form of a hollow screw shaft structure containing multiple tuned mass dampers (MTMD) to achieve the lateral multi-mode vibration control of the screw shaft. The screw shaft is modeled as an Euler-Bernoulli beam with elastic supports at both ends and the position of the nut. Each tuned mass damper (TMD) is connected to the screw shaft via an elastic spring and a viscous damping element. After establishment of the lateral dynamic model of the screw shaft which taking into account the changing positon of the nut and the multiple resonant responses of the shaft, the optimum design parameters of each TMD can be determined using a numerical optimization algorithm based on the mode summation method. The multiple resonant responses of the screw shaft installed with the optimally designed MTMD are analyzed to demonstrate the robust design of the MTMD for the lateral time-varying vibration control of the screw shaft. Theoretical studies and experimental results show that the proposed design method of the MTMD can remarkably improve the lateral dynamic stiffness of the screw shaft.


      PubDate: 2016-05-13T16:40:14Z
       
  • Investigation on the position drift of the axis average line of the
           aerostatic bearing spindle in ultra-precision diamond turning
    • Abstract: Publication date: Available online 12 May 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): P. Huang, W.B. Lee, C.Y. Chan
      To evaluate the performance of the spindle, many techniques have been proposed to measure the spindle error motion. However, few studies have focused on the investigation of the position drift of the axis average line (AAL). In the present study, the AAL of the aerostatic bearing spindle is investigated both theoretically and experimentally. An error model is developed to analyze the errors which contribute to the error of depth of cut in slow tool servo assisted turning. Moreover, an experiment of microstructure fabrication is conducted to investigate the amplitude error of microstructures along both axial and radial direction of the cylindrical workpiece. The effects of spindle error motion, spindle unbalance induced eccentricity, thermal error and position drift of AAL are analyzed. The results indicates that the position drift of AAL varies significantly in terms of the variation of the spindle speed due to the hydrodynamic effect, and the relation between the drift and the spindle speed is nonlinear.


      PubDate: 2016-05-13T16:40:14Z
       
  • Continuous trench, pulsed laser ablation for micro-machining applications
    • Abstract: Publication date: Available online 5 May 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): G.B.J. Cadot, D.A. Axinte, J. Billingham
      The generation of controlled 3D micro-features by pulsed laser ablation in various materials requires an understanding of the material's temporal and energetic response to the laser beam. The key enabler of pulsed laser ablation for micro-machining is the prediction of the removal rate of the target material, thus allowing real-life machining to be simulated mathematically. Usually, the modelling of micro-machining by pulsed laser ablation is done using a pulse-by-pulse evaluation of the surface modification, which could lead to inaccuracies when pulses overlap. To address these issues, a novel continuous evaluation of the surface modification that use trenches as a basic feature is presented in this paper. The work investigates the accuracy of this innovative continuous modelling framework for micro-machining tasks on several materials. The model is calibrated using a very limited number of trenches produced for a range of powers and feed speeds; it is then able to predict the change in topography with a size comparable to the laser beam spot that arises from essentially arbitrary toolpaths. The validity of the model has been proven by being able to predict the surface obtained from single trenches with constant feed speed, single trenches with variable feed speed and overlapped trenches with constant feed speed for three different materials (graphite, polycrystalline diamond and a metal-matrix diamond CMX850) with low error. For the three materials tested, it is found that the average error in the model prediction for a single trench at constant feed speed is lower than 5 % and for overlapped trenches the error is always lower than 10 %. This innovative modelling framework opens avenues to: (i) generate in a repeatable and predictable manner any desired workpiece micro-topography; (ii) understand the pulsed laser ablation machining process, in respect of the geometry of the trench produced, therefore improving the geometry of the resulting parts; (iii) enable numerical optimisation for the beam path, thus supporting the development of accurate and flexible computer assisted machining software for pulsed laser ablation micro-machining applications.


      PubDate: 2016-05-07T13:09:02Z
       
  • Cutting forces in micro-end-milling processes
    • Abstract: Publication date: Available online 6 May 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Xuewei Zhang, Kornel F. Ehmann, Tianbiao Yu, Wanshan Wang
      Micro-end-milling is capable of machining complex structures in a wider variety of materials at the micro- and meso-scales as compared to other micro machining processes. However, the exact prediction of cutting forces in micro-end-milling is still not fully developed. In order to predict the general three-dimensional cutting force components, the related cutting edge radius size-effect, tool run-out, tool deflection and the exact trochoidal trajectory of tool flute are considered and presented in the proposed analytical prediction model. The proposed cutting force model also includes an algorithm for the calculation of the variable entry and exit angles caused by tool run-out and tool deflection. In the cutting force prediction model, the actual instantaneous uncut chip thickness is evaluated by considering the theoretical instantaneous uncut chip thickness, the minimum uncut chip thickness and a certain critical chip thickness value governed by three types of material removal mechanisms, in the elastic and the elastic-plastic deformation region and the complete chip formation region, respectively. To verify the model, the parameters of tool run-out and tool deflection were obtained from experimental measurements. The proposed cutting force model is validated through micro slot end milling tests with a two-flute carbide micro-end-mill on Al6061 workpieces. The experimental results agree with simulation results very well. The proposed theoretical model offers a basis for real-time machining process monitoring as well as cutting parameters optimization.


      PubDate: 2016-05-07T13:09:02Z
       
  • A load identification method for the grinding damage induced stress (GDIS)
           distribution in silicon wafers
    • Abstract: Publication date: Available online 29 April 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Ping. Zhou, Shance Xu, Ziguang Wang, Ying Yan, Renke Kang, Dongming Guo
      Subsurface damage (SSD) and grinding damage induced stress (GDIS) result in deformation and strength degradation of a ground silicon wafer. The Stoney equation is widely used as a non-destructive method for finding GDIS in a silicon wafer prepared by the rotational grinding method. However, the basic assumptions of the Stoney equation ignore the detailed information on the GDIS in a ground wafer. In this paper, a new method is proposed for analyzing GDIS distribution in a silicon wafer thinned by grinding. The wafer is diced into small chips for identification of stress state with a load identification method. The results show that the stresses are not independent of the direction as assumed in the Stoney equation, and the ratio of the two principal stresses in the damage layer is approximately 2:3 under the grinding conditions of a #3000 diamond wheel with a spark-out time of 5 seconds. Moreover, the principal stress direction is obviously aligned with the grinding direction but independent of the crystalline orientation. The SSD is observed with a Transmission Electron Microscope (TEM), which shows numerous plane defects parallel to the {111} planes. It can be deduced from the results that the defects are non-uniformly distributed in the subsurface with their directions in the slip direction of the grinding abrasives. However, the principal stresses at any points have their respective values close to each other. The results of this study are unique and unexpected.


      PubDate: 2016-05-02T12:56:34Z
       
  • Origins for the size effect of surface roughness in diamond turning
    • Abstract: Publication date: Available online 7 April 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): C.L. He, W.J. Zong, T. Sun
      In this work, a novel surface roughness prediction model, in which the kinematics, plastic side flow, material spring back and random factors are considered, is theoretically formulated to reveal the underlying mechanisms for the observed size effect of surface roughness in diamond turning. In this newly developed model, the copy effect of tool edge waviness is successively integrated into the kinematic component, and a yield stress and minimum undeformed chip thickness related function is constructed for calculating the material spring back. For the component of plastic side flow, the effects of minimum undeformed chip thickness, tool nose radius, feed rate as well as cutting width are took into account. Moreover, the component of random factors is assumed to follow a Gaussian distribution. Theoretical predictions and experimental validations show that the feed rate dependent size effect of surface roughness as observed on the fine grain substrate is derived from the decrement of the kinematic component being less than the increment of the plastic side flow component. For the coarse grain substrate, the large and hard inclusion inevitably appears in the matrix. Therefore, the size effect of surface roughness can be attributed to the formation of pit defect and deep groove on the finished surface at large feed rate and the protrusion of hard inclusion from the finished surface at low feed rate.
      Graphical abstract image

      PubDate: 2016-04-09T04:36:49Z
       
  • Dual laser beam revising the separation path technology of laser induced
           thermal-crack propagation for asymmetric linear cutting glass
    • Abstract: Publication date: Available online 8 April 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Chunyang Zhao, Hongzhi Zhang, Lijun Yang, Yang Wang, Ye Ding
      Owing to the properties of high-transmittance, wear-resisting and lightweight brittle, glass plays an important role in various electronic equipment screens. The laser induced thermal-crack propagation (LITP) can separate the glass with the advantage of the high-quality, high-efficiency and high-strength. However, the deviation of the separation path (which means the material don′t separate in the path of laser scanning) is one of the serious problems in asymmetric linear cutting glass with LITP. In this study, a dual laser beam revision the separation path technology (DLBRP) has been developed for the first time by skillfully arranging two defocused diode pump solid state laser (1064nm). The principle of DLBRP is expounded. This paper studied several factors's effects on the cutting quality such as Master laser power (P M ), scanning speed (V M ) and laser spot diameter (D M ).The smaller the Master laser spot diameter, the smaller deviation of the separation path. The effects of revision factors including Accompanying laser power (P A ), Accompanying laser spot diameter on the material surface (D A ) and the horizontal relative distance between the Master laser and Accompanying laser (∆X) were investigated. The optimum processing parameters were presented in this paper. The cambered separation path (which means the material gets separated in the arc way) in asymmetry linear cutting glass (which means the cutting path deviating from the symmetry axis of the material in a large scale, and the area of two separated parts is varied widely) could be revised into the straight one. A numerical simulation on the thermal stress and the dynamic propagation of crack in the DLBRP for asymmetric linear cutting glass with LITP was developed to analyze the revision mechanism, which is corresponding to the theoretical analysis and experimental results. The analysis of experimental results and numerical simulation results shows that the DLBRP technology can effectively revise the deviation of the separation path in asymmetry linear cutting glass with LITP. Besides, the clean surface without any pollution and surface damage can be achieved.


      PubDate: 2016-04-09T04:36:49Z
       
  • Investigation of non-uniform preload on the static and rotational
           performances for spindle bearing system
    • Abstract: Publication date: Available online 2 April 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Li. Xiaohu, Li Huanfeng, Zhang Yanfei, Hong Jun
      In order to eliminate the deflection of spindle under external loading, a new non-uniform preload for spindle bearing system is proposed in this paper, and the effect of non-uniform preload on the static and rotational performances of the spindle system is explored both theoretically and experimentally. Seeking to reveal the role of non-uniform preload in spindle static and rotational performances under external radial loading, the equivalent transformation model is firstly built to simplify the non-uniform preload applied on the bearing. Then a simulation model is employed to analyze the variable static and rotational performances of spindle under different preload conditions. A test rig is designed to equip with spindle bearing system, inside which the measurement system is arranged to experimentally investigate how the spindle static and rotational accuracy are influenced by non-uniform preload, varying external load and rotating speeds. The results under different preload conditions show that the non-uniform preload with reasonable equivalent magnitude and direction can effectively adjust the spindle rotating center and compensate the spindle rotation error, and thus improves the rotational accuracy of the spindle system under complicated and alternating working conditions. This provides a new compensation method to the spindle deflection and rotational motion error through adjusting the non-uniformly distributed preload on the spindle bearing system.


      PubDate: 2016-04-05T12:29:54Z
       
  • Effect of drilling allowance on TBC delamination, spatter and re-melted
           cracks characteristics in laser drilling of TBC coated superalloys
    • Abstract: Publication date: Available online 2 April 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhengjie Fan, Xia Dong, Kedian Wang, Wenqiang Duan, Rujia Wang, Xuesong Mei, Wenjun Wang, Jianlei Cui, Xin Yuan, Chengying Xu
      Laser drilling of inclined holes on Ni-based superalloys coated with thermal barrier coatings (TBC) was studied using numerical simulation and experiments. Two types of drilling, three steps-laser drilling (TSLD) method and the one step laser drilling (OSLD), were employed for making comparison. The simulation results demonstrate that relatively strong vortex effect of assist gas at hole entrance and the drilling allowance of the substrate hole can deflect the trajectories of melt flow from leading edge TBC wall. This phenomenon may isolate leading edge of the hole from the ejecting molten material. Thus, shearing stress effect was prevented. The characteristics of TBC delamination, spatter at the TBC leading edge and re-melted cracks along the TBC trailing edge are investigated by comparing the characteristics of the melt flow obtained via simulation and experiment. The combined results suggest that the TBC/substrate multilayer can avoid these defects applying the TSLD technology.


      PubDate: 2016-04-05T12:29:54Z
       
 
 
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
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2016