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  Subjects -> MANUFACTURING AND TECHNOLOGY (Total: 292 journals)
    - CERAMICS, GLASS AND POTTERY (26 journals)
    - MACHINERY (33 journals)
    - PACKAGING (16 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: 18)
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: 5)
Engenharia AgrĂ­cola     Open Access  
Foundations and Trends® in Electronic Design Automation     Full-text available via subscription  
High Speed Machining     Open Access   (Followers: 1)
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: 5)
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 Mechanics     Hybrid Journal   (Followers: 16)
Journal of Strain Analysis for Engineering Design     Hybrid Journal   (Followers: 5)
Journal of Terramechanics     Hybrid Journal   (Followers: 1)
Machine Design     Partially Free   (Followers: 64)
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: 1)
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: 3.363]   [H-I: 81]   [5 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0890-6955
   Published by Elsevier Homepage  [2969 journals]
  • Pulsed ultrasonic assisted electrical discharge machining for finishing
    • 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
    • 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
    • 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
  • Chatter free tool orientations in 5-axis ball-end milling
    • Abstract: Publication date: Available online 20 April 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Sun Chao, yusuf Altintas
      Dies, molds and parts with complex free form surfaces are usually machined with ball end mills on 5-axis CNC machining centers. This paper presents automatic adjustment of tool axis orientations to avoid chatter along the tool path. The process mechanics and dynamics of ball end milling are modeled in cutter-workpiece engagement coordinate system. The structural dynamics of tool and workpiece are transformed to cutter-workpiece engagement coordinates by considering the tool path and the kinematics of the machine tool. The stability of the 5-axis ball end milling is modeled at each tool path location, and the chatter free tool axis orientations are searched iteratively using Nyquist criterion while avoiding gouging limits. The tool path, i.e. cutter location (CL) file, is updated to generate chatter free, 5-axis ball end milling of the parts. The proposed algorithm has been experimentally proven in 5-axis ball end milling tests.

      PubDate: 2016-04-23T17:53:58Z
  • Review of micro/nano machining by utilizing elliptical vibration cutting
    • Abstract: Publication date: Available online 22 April 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jianguo Zhang., Tao Cui, Cheng Ge, Yongxin Sui, Huaijiang Yang
      Textured surfaces with sophisticated micro/nano structures can provide interesting and advanced functions. In order to promote those unique functions into the practical use, high performance manufacturing technologies are required. Nowadays, elliptical vibration cutting (EVC) is attracting more and more attentions due to its excellent machining performances, especially the advantageous in the precision machining of difficult-to-cut materials. The emphasis on this literature review is the micro/nano machining technology by applying EVC. The development of the EVC technology is simply introduced, and then the advantageousness of EVC in the machining process is explored in detail. As following, the development of different EVC devices are introduced, and the applications of the micro/nano structure fabrication is detailedly expatiated by applying the different types of elliptical vibrators. By controlling the motion of the ultra-precision machine tool itself, the micro/nano structure can be accurately fabricated on various workpiece materials with the reduction of cutting forces, burr generation, tool wear, et al. in EVC process. Moreover, a unique amplitude control sculpturing method, where the depth of cut is arbitrary changed by controlling the vibration amplitude in the machining process, is introduced. By applying the amplitude control sculpturing method, ultra-precision micro/nano structures can be efficiently sculptured especially on the difficult-to-cut materials. Finally, the elliptical vibration texturing process is also explored in the fast micro/nano machining of the simple and regular structures. The EVC technology is expected to promote the development of micro/nano machining process in the actual industrial applications.

      PubDate: 2016-04-23T17:53:58Z
  • An experimental and theoretical investigation on the brittle ductile
           transition and cutting force anisotropy in cutting KDP crystal
    • Abstract: Publication date: Available online 23 April 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Shengfei Wang, Chenhui An, Feihu Zhang, Jian Wang, Xiangyang Lei, Jianfeng Zhang
      As a typical brittle material, Potassium Dihydrogen Phosphate (KDP) crystal exhibits anisotropic mechanical property during processing. The most general method to produce smooth and crack-free KDP surface is single point diamond fly-cutting (SPDF). In processing KDP by SPDF, cutting direction has great influence on the cutting force and the quality of the machined surface. Thus, selecting an optimal cutting direction is of great significance in decreasing the cutting force and improving the surface quality. In this paper, influence of cutting direction on the brittle ductile transition (BDT) depth and cutting force in machining KDP crystal has been investigated. Cutting experiments are carried out on the (001), Doubler and Tripler plane of KDP crystal to find out the change law of cutting force and BDT depth related to cutting direction. Theoretical models for calculating the cutting force and conditions for achieving crack-free surface in cutting by circular edge cutter have also been established. The predicted results coincide well with the experiment results, which have proved the validity of the proposed models. The experimental results in this study can provide guidelines for optimizing the processing parameters in fly-cutting of KDP crystal, and the theoretical models can be extended to study the cutting mechanism of other brittle materials.

      PubDate: 2016-04-23T17:53:58Z
  • Modelling of Cutting forces in orbital drilling of titanium alloy
    • Abstract: Publication date: Available online 14 April 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): P.A. Rey, J. LeDref, J. Senatore, Y. Landon
      Orbital drilling is a highly complex machining operation. Due to the tool helical trajectory, the chip thickness is highly variable along the cutting edges and during the tool revolution. This can be made even more difficult by the cutting tool geometry, which can be also very complex. This explains why cutting forces are very difficult to model and to estimate for different cutting tool geometries. The aim of this study is to develop a cutting forces model depending on the tool geometry and cutting conditions in order to control the final quality of the machined borehole. First, the geometry of the chip is modelled taking into account the parameters defining the trajectory and the tool geometry. A cutting force model, based on the instantaneous chip thickness, is then set up. An experimental study validates the modelling through measurements of cutting forces made during orbital drilling tests. From this modelling, it is possible to optimize the cutting parameters and the geometry of the cutting tool in order to control the loading on the tool and thus the final quality of the borehole.

      PubDate: 2016-04-19T12:37:37Z
  • IFC - Editorial board
    • Abstract: Publication date: June 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 105

      PubDate: 2016-04-14T12:14:08Z
  • 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
  • Impact-driven ejection of micro metal droplets on-demand
    • Abstract: Publication date: Available online 5 April 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jun Luo, Lehua Qi, Yuan Tao, Qian Ma, Claas Willem Visser
      On-demand metal droplet deposition will be a cornerstone technology in 3D metal printing. However, suitable small nozzles are hardly available, limiting the resolution and surface finish of final products. Here, the ejection of record-small metal droplets with a diameter of only 0.55±0.07 times the nozzle diameter was demonstrated. To this end, a novel metal drop-on-demand (DoD) generator for high-temperature metal processing was designed and manufactured. A metal rod was utilized to transfer a vibration pulse, which was required to eject a liquid droplet, from a low-temperature region to the high-temperature liquid metal close to the nozzle. The influence of the pulse characteristics on the droplet ejection regime was studied experimentally and numerically. A 2D axisymmetric numerical model revealed that the shorter pulses allow reducing the droplet size, with the pulse duration of 13μs resulting in the smallest feasible droplets. A novel method to create such short pulses, by impacting the metal-ring connected rod with a solid impactor was manufactured and tested, and the benefits of this method over more the spring-type pulse transfer was experimentally confirmed. This research provides a feasible way to achieve ejection of the small metal droplet on-demand.

      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
  • A comprehensive error analysis method for the geometric error of
           multi-axis machine tool
    • Abstract: Publication date: Available online 3 April 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jian-xiong Chen, Shu-wen Lin, Xiao-long Zhou
      In this paper, a comprehensive error analysis method is proposed to discover how the geometric error propagation through every motion axis, and to find out which error parameters have greater impact on the tool posture error at the end of the kinematic chain. As the geometric error of a motion axis can be regarded as the differential movement, an error model for a four-axis machine tool is established to calculate the tool posture error with all the geometric error parameters. Then a cumulative process of the differential movements of every axis is proposed to describe the error propagation process when moving the tool to the given position. Moreover, the workspace of the machine tool is discretized into an amount of points with a uniform sampling method on the measured positions of the geometric error. Then, a Spearman rank correlation method is presented to find out how closely linked between a single error parameter and the tool posture error all over the sampling workspace. Hence, the ten key error parameters are selected according to the analysis results in the three-axis and four-axis sampling workspace. Finally, an experiment is conducted on the four-axis machine tool with a three-axis controlled trajectory to verify the effectiveness and correctness of the proposed method using a double ballbar.

      PubDate: 2016-04-05T12:29:54Z
  • Micro-dimple pattern process and orthogonal cutting force analysis of
           elliptical vibration texturing
    • Abstract: Publication date: Available online 29 March 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Rendi Kurniawan, Gandjar Kiswanto, Tae Jo Ko
      Elliptical vibration cutting (EVC) has been studied extensively due to its superior performance. Benefits include reduced cutting force, tool wear, burrs, and surface roughness. This paper demonstrates the fabrication of a micro-dimple pattern using elliptical vibration texturing (EVT) based on the EVC method. An analytical model of the texturing process and an orthogonal cutting force analysis are presented. The micro-dimples were successfully established on Al-6061 using different vibration frequencies. The accuracy of the micro-dimples was measured and compared to an analytical model in order to validate the texturing process. The orthogonal cutting force model was used to simplify the cutting mechanism analysis. The effect of transient shear angle is not considered in the texturing process due to the small slope angle of the tool path. The result shows that the analytical model of the cutting force corresponds well with the experimental data.

      PubDate: 2016-04-01T12:17:36Z
  • Modeling and compensation for spindle’s radial thermal drift error
           on a vertical machining center
    • Abstract: Publication date: Available online 18 March 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Kuo Liu, Mingjia Sun, Tiejun Zhu, Yuliang Wu, Yu Liu
      In the present work, spindle’s radial thermal drift error (RTDE) was studied on a vertical machining center. RTDEs in X-direction and Y-direction of a vertical machining center were tested and the main direction of RTDE was determined as Y-direction. RTDEs in Y-direction and temperatures in key points of spindle were tested using different rotating speeds. RTDE models under different postures were established and the compensation strategy was presented. Thereafter, the influence of geometric parameters on the prediction of results was obtained using advanced first order second moment method. The compensation effects were verified using both simulation and experiment. The results indicated that high accuracy and strong robustness can be achieved with the proposed model, even if the rotating speed of spindle randomly changed, or the spindle was disturbed by the cooling system.

      PubDate: 2016-03-18T09:23:48Z
  • Modeling and analysis of a novel approach in machining and structuring of
           flat surfaces using face milling process
    • Abstract: Publication date: Available online 12 March 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Mohammadjafar Hadad, Mohammadjavad Ramezani
      In this paper, a new and innovative method for regular structuring and special patterning of workpiece surface applying face milling process is presented. The patterns have been generated on surface by particular positioning of workpiece and tool, milling passes in different directions, and as well as special angular position of spindle in typical vertical milling machine. The model for the geometry of the cutting tool was first developed and subsequently, a new simulation model for surface pattern by face milling process was established. Mathematical models are presented to describe the cutting tool geometry and position (including orientation and location) in space. To verify this method, calculation and simulation programs (MATLAB and CAD programming software) are developed. This study provides a fundamental understanding for the pattern milling process, based on this, the influence of different milling process parameters on pattern geometry (including insert angles and radius) is discussed. The simulation results could be used to optimize the pattern milling and conventional milling processes, and also to improve the workpiece surface quality or predict the surface pattern by given face milling parameters.

      PubDate: 2016-03-14T18:37:03Z
  • IFC - Editorial board
    • Abstract: Publication date: May 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 104

      PubDate: 2016-03-14T18:37:03Z
  • Developments in electrochemical discharge machining: A review on
           electrochemical discharge machining, process variants and their hybrid
    • Abstract: Publication date: Available online 9 March 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Tarlochan Singh, Akshay Dvivedi
      Electrochemical discharge machining (ECDM) is a hybrid non-conventional machining process, used to machine electrically conductive and non-conductive materials. It is a preferred process to fabricate micro scale features like micro holes, micro channels, microwaves and 3-dimensional intricate shapes on variety of materials. In order to improve the efficacy of ECDM process, certain technical augmentations are provided with basic configuration of ECDM. These augmentations result in developments of ECDM process variants. Further, research community has developed ECDM based triplex hybrid methods for further process enrichment. This review article presents a comprehensive review of these recent developments in ECDM process, its variants and their triplex hybrid methods. The future research possibilities are identified and presented as research potentials.

      PubDate: 2016-03-14T18:37:03Z
  • Thermal volumetric effects under axes cycling using an invar R-test device
           and reference length
    • Abstract: Publication date: Available online 10 March 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Elie Bitar-Nehme, J.R.R. Mayer
      Thermal errors of machine tools are in part caused by the variation of ambient temperature as well as the heat internally generated by the machine. These deformations are a major source of quasi-static machining errors and are thought to be related to temperatures and temperature gradients within the machine structure. This article presents a study of the thermal volumetric behavior of a five-axis machine tool. The study uses direct volumetric error measurements within the machine work volume for specific combinations of five-axis commands. Thermally induced volumetric distortion errors are studied in relation to a specifically designed machine activity sequence during which the power at each of the five-axis motors and the spindle are measured. The experimental measurement setup consisting of a thermally stable volumetric error sensor and a reference scale bar is presented. The study allows quantifying the effect of every axis’ activity on the Cartesian components of the volumetric distortion. Rotary axes are found to be the major contributors to the tested machine's thermal errors. Thermal coupling is observed whereby the activity of a rotary axis strongly affects a neighbouring linear axis.

      PubDate: 2016-03-14T18:37:03Z
  • Identification and compensation of main machining errors on surface form
           accuracy in ultra-precision diamond turning
    • Abstract: Publication date: Available online 11 March 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Xianlei Liu, Xiaodong Zhang, Fengzhou Fang, Shugui Liu
      Ultra-precision diamond turning is widely used in manufacturing the optical surfaces with nanometric accuracy. However, the machining errors especially geometric errors have a significant influence on the form accuracy of machined surfaces. A machining error model for a three-axis ultra-precision lathe is established based on multi-body system (MBS) theory to study the effect of geometric errors on the coordinate distortion and form accuracy. The machining errors are classified into five categories according to the coordinate distortions direction. These errors generate the coordinate distortions along the X direction, Y direction, radial direction, circumferential direction, and axial direction respectively. Five error categories have different effects on different typical surfaces, and the main machining errors on the form accuracy are identified according to the difference of the form error distribution for different surface shapes. Simulation is implemented to verify the influence of the machining errors on the form accuracy. One plane-spherical surface was proposed and machined to separate the main machining errors, which are used to be compensated in the machining experiments. The form accuracy of one freeform surface is proved to achieve a significant improvement finally.

      PubDate: 2016-03-14T18:37:03Z
  • A generic instantaneous undeformed chip thickness model for the cutting
           force modeling in micromilling
    • Abstract: Publication date: Available online 9 March 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Li Kexuan, Zhu Kunpeng, Mei Tao
      The precise modeling of the instantaneous undeformed chip thickness is one of the key issues in the mechanics of micromilling. While most current models noticed the influences of the tool tip trochoidal trajectory and tool runout, they took account only the workpiece removed by immediate passing tooth but not more preceded teeth. These lead to inaccuracy when the single edge cutting occurred, which has been identified to be a prevalent phenomenon in micromilling operation. In this paper, the actual cutting area in micromilling is derived, and then a generic instantaneous undeformed chip thickness model is proposed by considering the cutting trajectory of all passing teeth in one cycle. Additionally, this study derives a criteria that could determine the single-edge-cutting phenomenon in multi-tooth micromilling from the geometric relations. The accuracy of the model is verified by the real experimental data and the result are shown superior to known models.

      PubDate: 2016-03-09T18:17:08Z
  • Corrigendum to: “A novel approach for the prediction of the milling
           stability based on the Simpson method” [Int. J. Mach. Tools Manuf.
           99 (2015) 43–47]
    • Abstract: Publication date: Available online 2 March 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhao Zhang, Hongguang Li, Guang Meng, Chong Liu

      PubDate: 2016-03-09T18:17:08Z
  • Effect of servo and geometric errors of tilting-rotary tables on
           volumetric errors in five-axis machine tools
    • Abstract: Publication date: Available online 10 February 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Wenzheng Ding, Xiaochun Zhu, Xiaodiao Huang
      The tilting-rotary table becomes a standard accessory for five-axis machine tools. An approach for volumetric errors evaluation taking into account servo and geometric errors of the tilting-rotary table is proposed in this paper. A simple machining model of volumetric circles is used to evaluate volumetric errors due to servo errors of the tilting-rotary table. A kinematic error model is used to predict the volumetric errors resulting from geometric errors associated with the tilting-rotary table. Then effects of the two error sources are added to predict the total volumetric errors. A test part obtained by improving the cone frustum specified in NAS979 is presented to validate this method. Cases studies with cutting experiments are carried out on a commercial five-axis machine tool. The results show that the proposed model is effective to evaluate the effect of servo and geometric errors of the tilting-rotary table on volumetric errors in the five-axis machine tool.

      PubDate: 2016-02-12T22:12:40Z
  • Generalized mechanics and dynamics of metal cutting operations for unified
    • Abstract: Publication date: May 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 104
      Author(s): Z.M. Kilic, Y. Altintas
      This paper presents the unified modeling of mechanics and dynamics of metal cutting operations such as turning, boring, drilling and milling. The distribution of chip thickness along the cutting edges of tools are evaluated using the generalized geometric and kinematic model of the operations [1]. The effect of relative vibrations between the cutting edge and workpiece segments are considered. The force contributed by each oblique cutting edge segment is evaluated from shear stress, shear angle and friction coefficient defined in orthogonal cutting data base. The tool cutting loads are evaluated by summing the differential cutting forces along all engaged cutting edges using the generalized geometric transformations presented in [1]. The chatter stability is solved in modal coordinate system, and the forced vibration marks left on the finish surface are predicted in discrete time domain. The process damping, multiple-regenerative phase delays which depend on the tool geometry and operations are considered. The application of the proposed unified mechanics and dynamics model is demonstrated experimentally in drilling, milling with indexable cutters and various end mills, and in opening large holes with multi-functional drilling/boring heads.

      PubDate: 2016-02-08T04:29:35Z
  • Generalized modelling of cutting tool geometries for unified process
    • Abstract: Publication date: Available online 22 January 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Z.M. Kilic, Y. Altintas
      This paper presents a generalized geometric model of cutting tools for the purpose of predicting the mechanics and dynamics of machining operations. The model starts by defining the tangent and rake face vectors at discrete elements along the cutting edge. The discrete cutting edge elements are assembled mathematically to form either an insert or solid cutting edge, which are further transformed to design turning, boring, drilling, milling and other tools by considering the geometry and kinematics of cutting operations. Homogeneous transformation matrices are used to successively locate and orient the cutting edge within the insert, tool and process coordinate frames. Industry-standard tool-in-use planes are used to obtain the effective geometry for all cutting operations. In total 15 geometric parameters are used for identifying the geometry of an arbitrary tool. Radial and axial runouts are considered in the model. Generalized model is demonstrated by modelling the geometry of sample drills, indexable and serrated milling tools. The generalized model allows unified prediction of machining operations with one mathematical model which covers all operations and tool geometries.

      PubDate: 2016-01-23T01:43:34Z
  • An accurate prediction method of cutting forces in 5-axis flank milling of
           sculptured surface
    • Abstract: Publication date: Available online 31 December 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Xing Zhang, Jun Zhang, Bo Pang, WanHua Zhao
      The instantaneous uncut chip thickness and entry/exit angle of cutter/workpiece engagement continuously vary with tool path and workpiece geometry in 5-axis flank milling of sculptured surface, which results in the obvious time-varying characteristic for consecutive cutting forces. An accurate prediction method for cutting force in 5-axis flank milling of sculptured surface is proposed in this paper. Comprehensively considering curved tool path and actual tool motion process with cutter runout (offset and inclination) effects, an accurate representation model for instantaneous uncut chip thickness during cutter/workpiece engaging in 5-axis flank milling is presented firstly, which can reach a higher accuracy and efficiency with the aid of linear iteration process than the methods published. Then, based on the thin plate milling experiments, an efficient calibration procedure for cutter runout parameters and specific cutting force coefficients is given and further verified in practice. Finally, a series of validation experiments are conducted under different cutting conditions, and the results reveal that there is a very good agreement between the experimental and simulation data both in shape and magnitude and prove the effectiveness and accuracy of the proposed method.

      PubDate: 2016-01-03T09:35:52Z
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Heriot-Watt University
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