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  Subjects -> MANUFACTURING AND TECHNOLOGY (Total: 296 journals)
    - CERAMICS, GLASS AND POTTERY (26 journals)
    - MACHINERY (33 journals)
    - PACKAGING (15 journals)
    - PLASTICS (28 journals)
    - RUBBER (2 journals)

MACHINERY (33 journals)

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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: 6)
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: 101)
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  [3043 journals]
  • 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)
  • 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
    • 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
  • Global Tool-path Smoothing for CNC Machine Tools with Uninterrupted
    • Authors: Shingo Tajima; Burak Sencer
      Abstract: Publication date: Available online 16 March 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Shingo Tajima, Burak Sencer
      Majority of tool-paths for high-speed machining is composed of series of short linear segments, so-called G01 moves. This discrete tool-path format limits the achievable speed and accuracy of CNC machines. To generate continuous feed motion along sharp cornered tool-paths, most NC systems smooth corners locally using a pre-specified curve or a spline and slow down to be able to change the feed direction within machine kinematic limits. Path speed is dramatically reduced for accuracy if sharp corners are within close vicinity. This paper proposes a new real-time interpolation algorithm for NC systems to generate continuous rapid feed motion along short segmented linear tool-paths by smoothing local and adjacent corners that are within close vicinity. Instead of locally modifying the corner geometry with a spline, the proposed algorithm directly blends axis velocities between consecutive linear segments based on the jerk limited acceleration profile (JLAP) and generates cornering trajectories within user-specified contour errors and kinematic limits of the drives. A novel Look-Ahead Windowing (LAW) technique is developed to plan tangential feed profile with uninterrupted acceleration to continuously smooth the path. The feed profile is optimized to generate rapid motion along overlapping adjacent corners. Simulation and experimental results demonstrate effectiveness of the proposed method to interpolate accurate Cartesian high-speed motion along short-segmented tool-paths for machining free-form surfaces found in dies, molds and aerospace parts.

      PubDate: 2017-03-20T03:16:31Z
      DOI: 10.1016/j.ijmachtools.2017.03.002
  • 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
  • IFC - Editorial board
    • Abstract: Publication date: March 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 114

      PubDate: 2017-02-10T13:07:40Z
  • 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
  • Tool deflection model and profile error control in helix path contour
    • Authors: Yanglin Peng; Yifan Dai; Ci Song; Feng Shi
      Pages: 1 - 8
      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
      DOI: 10.1016/j.ijmachtools.2016.08.005
      Issue No: Vol. 111 (2016)
  • Functional Accuracy Investigation of Work-Holding Rotary Axes in Five-Axis
           CNC Machine Tools
    • Authors: Mehrdad Vahebi Nojehdeh; Behrooz Arezoo
      Pages: 17 - 30
      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
      DOI: 10.1016/j.ijmachtools.2016.09.002
      Issue No: Vol. 111 (2016)
  • IFC - Editorial board
    • Abstract: Publication date: February 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 113

      PubDate: 2016-12-26T08:43:25Z
  • Analysis of the wear of forging tools surface layer after hybrid surface
    • Authors: Marek Hawryluk; Zbigniew Gronostajki; Marcin Kaszuba; Sławomir Polak; Paweł Widomski; Jerzy Smolik; Jacek Ziemba
      Abstract: Publication date: Available online 23 December 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Marek Hawryluk, Zbigniew Gronostajki, Marcin Kaszuba, Sławomir Polak, Paweł Widomski, Jerzy Smolik, Jacek Ziemba
      The performed research involved a thorough analysis of the phenomena occurring at an early stage of performance of selected forging tools – stamps (up to 4000 manufactured forgings), used in the second hot forging operation of a lid-type forging, which made it possible to point to the hybrid layer with the highest wear resistance, in order to increase tool life. Three different coatings were applied: AlCrTiSiN, Cr/CrN and AlCrTiN. The coatings were tested on 19 tools, and 3 representatives for each coating were selected, followed by their through research analysis. In particular, the analysis concerned the manner of wear of the hybrid layers and their resistance to specific degradation mechanisms. Based on the performed studies, it was possible to select the most optimal hybrid layer, which allows one to improve tool life. The preliminary results showed that the best effects for the whole tool working surface were obtained for the Cr/CrN layer, characterizing in high adhesion as well as the lowest Young's modulus E and hardness. In the case of high tool forces and the related friction, the best results were obtained for the AlCrTiN coating, which, beside its good adhesion properties, also characterizes in the highest abrasive wear resistance.

      PubDate: 2016-12-26T08:43:25Z
      DOI: 10.1016/j.ijmachtools.2016.12.010
  • 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
  • Evaluation of tool steel alloy performance in a milling operation through
           operational dynamic parameters
    • Authors: Tomas Österlind; Lorenzo Daghini; Andreas Archenti
      Abstract: Publication date: Available online 22 December 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Tomas Österlind, Lorenzo Daghini, Andreas Archenti
      Dynamic characteristics of machine tools and cutting tools have gained much attention from researchers and industry as it is one of the major factors limiting productivity due to excessive vibrations such as chatter during the cutting process. Numerous factors have to be taken into consideration when selecting material of the cutter body. This paper presents a comparison between two cutter bodies with the same geometry but made out of different alloys. Pre-hardened steel and conventional tool steel were investigated in order to highlight the advantages of selecting correct material to achieve high performance tools with respect of chatter resistance. The experimental part of this paper consists of impact testing, machining tests and surface integrity measurements. Operational dynamic parameters obtained through auto-regressive moving average model estimates from machining tests under stable and unstable conditions was used to characterise the performance. The findings are in correlation with material damping research and chatter analysis, thus giving a strong coupling to material selection in tool holders for enhanced process stability. The research also shows that operational dynamic properties obtained through indirect measurements is a valuable tool for process stability characterisation.

      PubDate: 2016-12-26T08:43:25Z
      DOI: 10.1016/j.ijmachtools.2016.12.009
  • 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
  • A buckling model for flange wrinkling in hot deep drawing aluminium alloys
           with macro-textured tool surfaces
    • Authors: Kailun Zheng; Junyi Lee; Jianguo Lin; Trevor A. Dean
      Abstract: Publication date: Available online 18 December 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Kailun Zheng, Junyi Lee, Jianguo Lin, Trevor A. Dean
      The work described in this paper is the development of a buckling model based on the classical energy method of flange area material using a one-dimensional beam geometry assumption to predict flange wrinkling in hot deep drawing aluminium alloys with macro-textured blankholder surfaces. A series of deep drawing experiments utilising different macro-textured tool surfaces were performed to investigate the effects of process parameters and texture features on flange wrinkling. The results have shown that wrinkling occurs when the hollow dimension of radially grooved textures reached a certain magnitude dependent on process conditions. A dislocation-driven based damage mechanism (CDM) material model for aluminium alloys at elevated temperatures was used to model the viscoplastic behaviour during deformation. The newly developed buckling model was validated by comparison with experimental results. The predicted results showed that the resistance to wrinkling increases with increasing forming temperature and decreasing forming speed, depending on the particular viscoplastic characteristics of the work-piece. The effects of texture ratio and draw ratio on wrinkling were found to be more significant than the effects of the temperature and strain rate. The buckling model developed in this paper can be used to model the flange wrinkling phenomena, as well as the non-isothermal feature in the hot stamping condition using the macro-textured tool surfaces.

      PubDate: 2016-12-19T07:56:27Z
      DOI: 10.1016/j.ijmachtools.2016.12.008
  • 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
  • A Comparative Investigation on Temperature Distribution in Electric
           Discharge Machining Process through Analytical, Numerical and Experimental
    • Authors: Hamid Reza Fazli Shahri; Ramezanali Mahdavinejad; Mehdi Ashjaee; Amir Abdullah
      Abstract: Publication date: Available online 14 December 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Hamid Reza Fazli Shahri, Ramezanali Mahdavinejad, Mehdi Ashjaee, Amir Abdullah
      Electric discharge machining (EDM) is a widely-used non-traditional machining process in manufacturing of complicated structures based on localized thermal loads. Because of numerous difficulties in measuring temperature, no adequate knowledge on temperature distribution of workpiece, tool and plasma channel is available. On one hand, a large number of dispersedly-published papers have been reported so far to model the temperature distribution whether analytically or numerically. On the other hand, an enormous amount of experimental attempt has been put into measuring the temperature by directly-measuring methods. In this study, a comprehensive review of analytical, numerical and experimental investigations on temperature prediction has been provided to organize different methods to integrate them as useful information for elucidating the differences between approaches and identifying their proximities to the real temperature distribution. This review also prepares a classification of the different methods of investigating temperature and provides an overview of some of the recent advances in this area to help researchers on selecting appropriate approaches among analytical, numerical and experimental techniques depends on applications and the availabilities of those techniques. The assumptions, limitations and features of different methods are described. Finally, the paper shows some required enhancements for EDM process to improve the total accuracy of temperature prediction as well as recommendations for future studies.

      PubDate: 2016-12-19T07:56:27Z
      DOI: 10.1016/j.ijmachtools.2016.12.005
  • Mechanics of tapping process with emphasis on measurement of feed error
           and estimation of its induced indentation forces
    • Authors: Min Wan; Ying-Chao Ma; Jia Feng; Wei-Hong Zhang
      Abstract: Publication date: Available online 8 December 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Min Wan, Ying-Chao Ma, Jia Feng, Wei-Hong Zhang
      Feed error induced by the mismatch between the spindle motor and Z-axis motor of the machine can significantly influence the cutting loads during thread tapping process. In this paper, a comprehensive study, which allows predicting the feed error-induced force together with measuring the actual tapping feed error, is presented by establishing simplified methods. Convenient experimental setup and procedure are first proposed to measure the actual feed error by using a laser tachometer along with a laser interferometer, followed by modeling the contact status between the tap flank and workpiece under feed error as an indentation effect, under which the corresponding indentation force is derived as a simplified proportional function of the indentation volume by using the basic principle of contact mechanics. Identification scheme is also developed to determine the proportional coefficient, i.e. the indentation force coefficient. Total tapping forces are obtained by summing cutting forces related to material removal mechanism and the indentation forces associated with feed error. Experimental verifications have been carried out to validate the proposed methods.

      PubDate: 2016-12-12T14:18:32Z
      DOI: 10.1016/j.ijmachtools.2016.12.003
  • Influence of grain wear on material removal behavior during grinding
           nickel-based superalloy with a single diamond grain
    • Authors: Chenwei Dai; Wenfeng Ding; Jiuhua Xu; Yucan Fu; Tianyu Yu
      Abstract: Publication date: Available online 6 December 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Chenwei Dai, Wenfeng Ding, Jiuhua Xu, Yucan Fu, Tianyu Yu
      In order to explore the effect of grain wear on material removal behavior during grinding nickel-based superalloy Inconel 718, the grinding experiment with a single diamond grain was carried out. The variations of grain wear, grinding force and force ratio, and pile-up ratio were investigated under the conditions of undeformed chip thickness (UCT) ranging from 0.2 to 1 μm. The results show that a critical UCT value, such as 0.3 μm, could be determined according to the pile-up ratio and could also be used to quantify the material removal process. The wear behavior of a diamond grain shows four types, such as crescent depression on the rake face, abrasion on the flank face, grain micro-fracture, and grain macro-fracture. Furthermore, these classifications were determined by the dwell time of rubbing, ploughing and cutting at different UCT values applied. The grinding force ratio increased with increasing of the negative rake angle of a diamond grain. In the rubbing and ploughing stages, the material removal efficiency is proportional to the wear width on the rake face. However, in the cutting stage, the material removal efficiency is diminished in the absence process of crescent depression.
      Graphical abstract image

      PubDate: 2016-12-06T04:55:52Z
      DOI: 10.1016/j.ijmachtools.2016.12.001
  • 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
  • IFC - Editorial board
    • Abstract: Publication date: January 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 112

      PubDate: 2016-11-29T02:02:03Z
  • 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
  • Polishing-pad-free electrochemical mechanical polishing of
           single-crystalline SiC surfaces using polyurethane–CeO2 core–shell
    • Authors: Junji Murata; Koushi Yodogawa; Kazuma Ban
      Abstract: Publication date: Available online 26 November 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Junji Murata, Koushi Yodogawa, Kazuma Ban
      A novel method for electrochemical mechanical polishing (ECMP) of the single-crystalline SiC surface, which has extremely high mechanical and chemical strength compared to conventional electronic materials, is reported. The method does not employ a polishing pad; it comprises electrochemical oxidization of the SiC surface and subsequent removal of the oxide by CeO2 from the polyurethane–CeO2 core–shell particles. The core–shell particles are used to maintain a gap between the polishing plate (cathode) and the SiC wafer (anode), which enables efficient anodic oxidation of the inert SiC surface. The core–shell particles, composed of the elastic polyurethane core covered with an abrasive layer of small and soft CeO2 particles prepared by a simple and low-cost process, can be used to obtain a smooth SiC surface without using a polishing pad. The ratio of polyurethane to CeO2 in the core–shell particles is optimized to obtain core particles that are fully covered with the shell particles without leaving excess CeO2 particles. Using the fabricated core–shell particles, the conventional CMP process is unable to remove the SiC surface without anodization. While a continuous bias during polishing produces a rough SiC surface owing to the oxide film remaining on the treated surface, as confirmed by current measurements and X-ray analysis, a periodically applied bias, whose conditions were determined by the theoretical growth rate and residual thickness of the oxide film, reduces the number of scratches, and a smooth surface with sub-nanometer roughness is obtained. The obtained value of surface roughness is in good agreement with the calculated value determined using conventional grinding theory. Compared to a conventional polishing process with a colloidal SiO2 slurry, the proposed method shows superior polishing efficiency without the need for a polishing pad. SEM observation of the core–shell particles shows that the particles have durability against the strong electric field between the electrodes.

      PubDate: 2016-11-29T02:02:03Z
      DOI: 10.1016/j.ijmachtools.2016.11.007
  • A Computational Fluid Dynamics (CFD) Model for Effective Coolant
           Application in Deep Hole Gundrilling
    • Authors: K.S. Woon; G.L. Tnay; M. Rahman; S. Wan; S.H. Yeo
      Abstract: Publication date: Available online 25 November 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): K.S. Woon, G.L. Tnay, M. Rahman, S. Wan, S.H. Yeo
      Effective coolant application in deep hole gundrilling is crucial to prevent rapid degradation and failure of drills through high performance cooling, lubrication and chip evacuation. This paper presents a novel methodology to increase effectiveness of coolant application through strategic optimization of gun drill designs that leads to appreciable tool life improvement, based on computational fluid dynamics (CFD) analysis. Through the analyses of coolant flow characteristics and rheological properties, conventional designs of critical drill geometries like nose grind contour, coolant hole configuration and shoulder dub-off angle, which are detrimental to coolant application and hence tool life are determined. A new, optimized gun drill design for the drilling of deep holes on Ni-based alloys is proposed. All findings are experimentally substantiated.

      PubDate: 2016-11-29T02:02:03Z
      DOI: 10.1016/j.ijmachtools.2016.11.008
  • Upgraded stability analysis of milling operations by means of advanced
           modeling of tooling system bending
    • Authors: Totis Albertelli; Torta Sortino Monno
      Abstract: Publication date: Available online 25 November 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): G. Totis, P. Albertelli, M. Torta, M. Sortino, M. Monno
      The problem of undesired self-excited chatter vibrations in milling is very common. However, only in the last two decades some significant achievements for the theoretical understanding of this intricate phenomenon have been accomplished. Nevertheless, state of the art dynamic models are still not able to completely explain milling dynamics and chatter onset during some conventional milling operations performed by conventional cutting tools. In this research work, a revolutionary model of tooling system dynamics and of the regenerative effect in milling will be presented. The new model introduces a significant correction to the predicted stability borders when the cutter diameter is relatively large in comparison with tooling system overhang and when curved or inclined cutting edges are applied. Accordingly, the new approach may be of great interest for many industrial applications. The model has been successfully validated by performing experimental modal analysis, cutting force coefficient identification and stability lobes diagram determination, through many specific cutting tests. In the considered case study, where the afore mentioned geometrical features of the tooling system were still moderate, a significant shift of the stability borders of about +25% was experimentally observed and correctly predicted by the new approach.
      Graphical abstract image Highlights

      PubDate: 2016-11-29T02:02:03Z
  • Robustness Modeling Method for Thermal Error of CNC Machine Tools Based on
           Ridge Regression Algorithm
    • Authors: Hui Liu; Ming Miao Xin Yuan Wei Xin Dong Zhuang
      Abstract: Publication date: Available online 23 November 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Hui Liu, En Ming Miao, Xin Yuan Wei, Xin Dong Zhuang
      For thermal error compensation technology of CNC machine tools, the collinearity between temperature sensitive points is the main factor for determining the predicted robustness of thermal error model. The temperature sensitive points are input variables of the thermal error model. This paper studies the thermal error of Leaderway V-450 type CNC machine tools during different seasons. It is found that although the commonly used temperature sensitive point selection methods can significantly reduce the collinearity between temperature sensitive points, the correlation between some of the selected temperature-sensitive points and thermal error is weak. This causes the temperature-sensitive points to be variable and the predicted accuracy and robustness of thermal error to be reduced. Therefore, in this paper, the temperature sensitive points are selected directly by their correlation with thermal error to eliminate variability. However, the experimental results also show that the collinearity between temperature sensitive points is very large. Hence, the ridge regression algorithm is used to establish a thermal error model to inhibit the bad influence of collinearity on the thermal error predicted robustness. Thus, the “robustness ridge regression machine tool thermal error modeling method” is proposed, the “RRR method” for short. In addition, in the “RRR method”, the correlation coefficient is used to measure the correlation between temperature sensitive points and thermal error instead of the commonly used gray correlation; because this paper finds that the gray correlation algorithm is essentially inapplicable for measuring a negative correlation. Based on the thermal error experiment data for the whole year, the “RRR method” is compared with two currently used methods, and the results show that the “RRR method” can significantly enhance the long-term predicted accuracy and robustness of thermal error. Finally, the application effect of practical compensation shows that the “RRR method” is usable and effective.

      PubDate: 2016-11-29T02:02:03Z
  • 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
  • IFC - Editorial board
    • Abstract: Publication date: December 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 111

      PubDate: 2016-11-02T07:48:31Z
  • Study on ductile mode machining of single crystal silicon by mechanical
    • Authors: Dae-Hee Choi; Je-Ryung Lee; Na-Ri Kang; Tae-Jin Je; Ju-Young Kim; Eun-chae Jeon
      Abstract: Publication date: Available online 1 November 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Dae-Hee Choi, Je-Ryung Lee, Na-Ri Kang, Tae-Jin Je, Ju-Young Kim, Eun-chae Jeon
      Nano patterns on single crystal silicon are generally manufactured by photolithography, which can form limited cross-sectional shapes such as U-shapes or rectangular channels. Though V-shaped patterns are widely used in the optical industries because they concentrate light, they are challenging to manufacture by conventional photolithography. Mechanical machining is useful in manufacturing various kinds of cross-sectional shapes including V-shapes with various apex angles, but is hard to apply to single-crystal silicon due to its brittle fracture. Here we suggest a novel way of mechanical machining of single-crystal silicon that suppresses brittle fracture below the critical point (the ductile-brittle transition point) as determined by nano scratch testing. We find that the first drop point of the cutting force corresponds to a critical point and define the critical forces as the thrust force and the cutting force at the critical point. The critical forces are varied by the applied force per unit length, which is the possibility that the cutting tool interacts with mechanically weak atomic bonds. When the applied force per unit length is zero (a general condition of mechanical machining), the cutting speed does not affect the variation of the critical forces or the quality of the machined pattern. Based on analysis of the experimental results, we suggest that the single-crystal silicon can be mechanically machined without brittle fracture at high cutting speed if the thrust force is smaller than the critical force of zero applied force per unit length.

      PubDate: 2016-11-02T07:48:31Z
      DOI: 10.1016/j.ijmachtools.2016.10.006
  • The concept and progress of intelligent spindles: A review
    • Authors: Hongrui Cao; Xingwu Zhang; Xuefeng Chen
      Abstract: Publication date: Available online 17 October 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Hongrui Cao, Xingwu Zhang, Xuefeng Chen
      Intelligent spindles are core components of the next-generation of intelligent/smart machine tools in the Industry 4.0 Era. The purpose of this paper is to clarify the concept of intelligent spindles and provide an in-depth review of the state-of-the-art of related technologies. A new integrated concept for intelligent spindles is proposed, followed by descriptions of required characteristics, key enabling technologies and expected intelligent functions. Relevant research that may be beneficial to the development of intelligent spindles is reviewed from six thrust areas, which include monitoring and control of tool condition, chatter, spindle collision, temperature/thermal error, spindle balance, and spindle health. Finally, current limitations and challenges are discussed, and future trends of intelligent spindles are prospected from various perspectives.
      Graphical abstract image

      PubDate: 2016-10-21T18:13:01Z
      DOI: 10.1016/j.ijmachtools.2016.10.005
  • Straightness error modeling and compensation for gantry type open
           hydrostatic guideways in grinding machine
    • Authors: Jun Zha; Fei Xue; Yaolong Chen
      Abstract: Publication date: Available online 6 October 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jun Zha, Fei Xue, Yaolong Chen
      This study presents an approach to model and compensate the vertical straightness error of gantry type open hydrostatic guideways. The straightness error is measured at different measurement points on the beam using a laser interferometer. To investigate different trends in the straightness error, a static analysis model is established, based on the error averaging effect considering the guiderail profile error. The linear deviation of the slider is computed and the vertical straightness error is calculated using a least-square method. The simulation results indicate that the measurement points have a big impact on the straightness error. The minimum value appeared when measurement point located at the middle of the X beam. And more closer to Y guide rails, higher value will be. The positions of the measurement points are chosen according to the change trend of the vertical straightness error. Finally, vertical straightness error is compensated and the compensation results are compared between different coordinate values. Experimental results show that the straightness error model and error compensation strategy help to effectively improve the accuracy of gantry type open hydrostatic guideways in grinding machines.

      PubDate: 2016-10-08T14:18:23Z
      DOI: 10.1016/j.ijmachtools.2016.10.002
  • Grinding forces in micro slot-grinding (MSG) of single crystal sapphire
    • Authors: J. Cheng; J. Wu; Y.D. Gong; X.L. Wen; Q. Wen
      Abstract: Publication date: Available online 6 October 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): J. Cheng, J. Wu, Y.D. Gong, X.L. Wen, Q. Wen
      Micro-slot grinding (MSG) is an important processing method for the micro-machining of hard brittle crystalline materials. Modelling the MSG of crystal material is necessary to understand its precision micro-machining aspects. In this paper, a predictive model is developed for the grinding force in MSG in three different orientations of single crystal sapphire: the C-orientation {0001}, A-orientation {11 2 ( _ ) 0} and R-orientation {1 1 ( _ ) 02} are established. The crystalline effects of the density of Al+, -Al+ and D Al +; the density of O- hollows D O -; the number of crystal layers ζ; and the weak shape of different orientations are incorporated. Three group experiments (144 paths) are performed, and the differences in the grinding forces from three orientations, {0001}, {11 2 ( _ ) 0} and {1 1 ( _ ) 02}, are discussed. The grinding forces of the A-orientation {11 2 ( _ ) 0} are higher than of the other two orientations {0001} and {110 2 ( _ ) }, and the number of crystal layers ζ is shown to play a vital role in determining the grinding force required for MSG of sapphire. The force ratio r F (F x/F y) is between 0.6 to 0.8, and the r F of {110 2 ( _ ) } is more stable than for the {11 2 ( _ ) 0} and {0001} orientations. A comparison with existing models and experimental data shows that the model used in this study fits the experimental data better, especially at lower feeding rates.

      PubDate: 2016-10-08T14:18:23Z
      DOI: 10.1016/j.ijmachtools.2016.10.004
  • Analytical Modeling for Thermal Errors of Motorized Spindle Unit
    • Authors: Teng Liu; Weiguo Gao; Dawei Zhang; Yifan Zhang; Wenfen Chang; Cunman Liang; Yanling Tian
      Abstract: Publication date: Available online 23 September 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Teng Liu, Weiguo Gao, Dawei Zhang, Yifan Zhang, Wenfen Chang, Cunman Liang, Yanling Tian
      Modeling method investigation about spindle thermal errors is significant for spindle thermal optimization in design phase. To accurately analyze the thermal errors of motorized spindle unit, this paper assumes approximately that 1) spindle linear thermal error on axial direction is ascribed to shaft thermal elongation for its heat transfer from bearings, and 2) spindle linear thermal errors on radial directions and angular thermal errors are attributed to thermal variations of bearing relative ring displacements. Based on prerequisites, an analytical modeling method is developed to analyze these spindle thermal errors. Firstly, thermal-mechanical models of rotating ring geometry and interference assembled rotating ring geometries are established, for thermal variation modeling of relative ring displacements of short cylindrical roller bearing and angular contact ball bearing. Secondly, these thermal variation models are associated with heat-fluid-solid coupling FE (finite element) simulation technique, to model spindle linear thermal errors on radial /axial directions and angular thermal errors by the analytical simulation method. Consequently, verification experiments clarify that the presented method is accurate for spindle thermal errors modeling, and can be effectively applied into the design and development phases of motorized spindle units.

      PubDate: 2016-09-24T08:04:24Z
      DOI: 10.1016/j.ijmachtools.2016.09.008
  • Research on the dynamics of ball screw feed system with high acceleration
    • Authors: Jun Zhang.; Huijie Zhang Chao Wanhua Zhao
      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
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Heriot-Watt University
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