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  Subjects -> MANUFACTURING AND TECHNOLOGY (Total: 297 journals)
    - CERAMICS, GLASS AND POTTERY (26 journals)
    - MACHINERY (33 journals)
    - MANUFACTURING AND TECHNOLOGY (184 journals)
    - METROLOGY AND STANDARDIZATION (4 journals)
    - PACKAGING (15 journals)
    - PAINTS AND PROTECTIVE COATINGS (5 journals)
    - PLASTICS (28 journals)
    - RUBBER (2 journals)

MACHINERY (33 journals)

Showing 1 - 33 of 33 Journals sorted alphabetically
Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9)
Advanced Energy Materials     Hybrid Journal   (Followers: 26)
Applied Mechanics Reviews     Full-text available via subscription   (Followers: 26)
BER : Consumer Goods Industries Survey     Full-text available via subscription  
BER : Intermediate Goods Industries Survey     Full-text available via subscription   (Followers: 1)
BER : Manufacturing Survey : Full Survey     Full-text available via subscription   (Followers: 2)
CORROSION     Full-text available via subscription   (Followers: 20)
Electric Power Components and Systems     Hybrid Journal   (Followers: 7)
Engenharia Agrícola     Open Access  
Foundations and Trends® in Electronic Design Automation     Full-text available via subscription  
High Speed Machining     Open Access   (Followers: 4)
High Temperature Materials and Processes     Hybrid Journal   (Followers: 5)
International Journal of Machine Tools and Manufacture     Hybrid Journal   (Followers: 7)
International Journal of Machining and Machinability of Materials     Hybrid Journal   (Followers: 6)
International Journal of Manufacturing Technology and Management     Hybrid Journal   (Followers: 8)
International Journal of Precision Technology     Hybrid Journal  
International Journal of Rapid Manufacturing     Hybrid Journal   (Followers: 4)
International Journal of Rotating Machinery     Open Access   (Followers: 2)
Journal of Machinery Manufacture and Reliability     Hybrid Journal   (Followers: 2)
Journal of Machinery Manufacturing and Automation     Open Access   (Followers: 2)
Journal of Modeling in Mechanics and Materials     Partially Free   (Followers: 1)
Journal of Strain Analysis for Engineering Design     Hybrid Journal   (Followers: 8)
Journal of Terramechanics     Hybrid Journal   (Followers: 5)
Machine Design     Partially Free   (Followers: 122)
Machines     Open Access   (Followers: 2)
Materials     Open Access   (Followers: 7)
Mechanics Based Design of Structures and Machines: An International Journal     Hybrid Journal   (Followers: 5)
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: 3)
Surface Engineering and Applied Electrochemistry     Hybrid Journal   (Followers: 6)
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  [3044 journals]
  • Laser powder bed fusion of nickel alloy 625: Experimental investigations
           of effects of process parameters on melt pool size and shape with spatter
           analysis
    • Authors: Luis E. Criales; Yiğit M. Arısoy; Brandon Lane; Shawn Moylan; Alkan Donmez; Tuğrul Özel
      Pages: 14 - 36
      Abstract: Publication date: October 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 121
      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 modeling studies and adopted for the industrial practice.

      PubDate: 2017-07-23T10:02:56Z
      DOI: 10.1016/j.addma.2016.11.004
      Issue No: Vol. 13 (2017)
       
  • Modelling of flow stress by correlating the material grain size and chip
           thickness in ultra-precision machining
    • Authors: M. Azizur Rahman; Mustafizur Rahman; A. Senthil Kumar
      Pages: 57 - 75
      Abstract: Publication date: December 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 123
      Author(s): M. Azizur Rahman, Mustafizur Rahman, A. Senthil Kumar
      Inducing compressive stress on the machined surface is a desirable practice in ultra-precision metal cutting to improve the part quality. An important parameter to analyse the machining performance is the material flow stress, which plays a crucial role in the material deformation characteristics in machining. As the dimensions of the workpiece descend from macro to micro scale in metal forming, the flow stress reduces accordingly. Hence, based on the ‘surface model’ analogy developed for metal forming coupled with the crystal plasticity effect, an attempt has been made in this study to construct a flow stress model for ultra-precision machining process. While developing the model, for the first time, the size factor (η, d/h o ) is introduced to incorporate the material ‘grain size effect’ in ultra-precision machining. The proposed model is validated with experimental results of Al6082 alloy of different grain sizes. Orthogonal turning experiments were conducted on an ultra-precision machine by utilizing the concept of ‘cutting edge radius effect’, which is identified as the relative tool sharpness (RTS) and quantified as the ratio of undeformed chip thickness (h c ) to edge radius (r n ). In this paper, the investigation on the material flow stress is carried out by considering the phenomenon of the shifting material flow separation (cutting) from primary deformation zone to material deformation (ploughing and rubbing) at tertiary deformation zone. The distribution of contact stresses along the tool rake and flank faces at the minimum value of RTS (h c /r n ) of 0.01 substantiates the ploughing effect (compressive stresses are induced into the machined layer) rather than chip separation. Moreover, the distinct variation of the machined surface quality and μ-chip morphology at the extreme low and high RTS conditions distinguishes the material ploughing effect from the cutting effect. Additionally, for the same RTS value, it is found that different grain materials (Cu and Mg alloy) exhibited variations in flow stress, chip morphology and surface quality. Therefore, material grain size is an influential factor for analysing machining performance with material flow stress at ultra-precision level.

      PubDate: 2017-09-02T14:20:40Z
      DOI: 10.1016/j.ijmachtools.2017.08.001
      Issue No: Vol. 123 (2017)
       
  • Calculation model for surface roughness of face gears by disc wheel
           grinding
    • Authors: Yanzhong Wang; Yang Liu; Xiaomeng Chu; Yueming He; Wei Zhang
      Pages: 76 - 88
      Abstract: Publication date: December 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 123
      Author(s): Yanzhong Wang, Yang Liu, Xiaomeng Chu, Yueming He, Wei Zhang
      Face gears have been widely used in the transmission systems of aviation and vehicle as a new form of transmission. In order to improve the bearing capacity and reliability of face gears, it is necessary to study the grinding surface roughness of face gears, so as to guide the grinding process of face gears. A mathematical model of roughness based on disc wheel grinding for face gears is proposed. The model can calculate tooth surface roughness based on grinding machining principle of face gear by disc wheel, considering roughness caused by material removal by grinding wheel wear and the discretized generating movement between grinding wheel and workpiece. Supported by the proposed model, the distribution of surface roughness of face gear is analyzed. The model is verified by experimental data, the influence of grinding parameters on the surface roughness is summarized, and the grinding optimization scheme is put forward.
      Graphical abstract image

      PubDate: 2017-09-02T14:20:40Z
      DOI: 10.1016/j.ijmachtools.2017.08.002
      Issue No: Vol. 123 (2017)
       
  • A selectively-coupled shear localization model for friction stir welding
           process window estimation
    • Authors: Xianjun Pei; Pingsha Dong
      Pages: 89 - 104
      Abstract: Publication date: December 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 123
      Author(s): Xianjun Pei, Pingsha Dong
      This paper presents a novel computational procedure specifically aimed at gaining modeling capabilities for estimating friction stir welding (FSW) process window. The proposed model first combines a three-dimensional (3D) transient heating effects with a one-dimensional (1D) shear localization process leading to shear band development within one pin revolution. The resulting shear band width is then compared with the minimum material flow layer thickness required for satisfying both mass conservation and velocity continuity conditions in a two-dimensional (2D) planar material flow around the tool pin. If the shear band width formed within one pin revolution is equal or larger than the minimum material flow layer thickness, conditions for developing a quality weld prevail. Otherwise, conditions for developing various forms of weld defects can be identified, depending upon shear localization behavior predicted. Specifically, the proposed model is shown capable of elucidating some of the major defect formation mechanisms observed in experiments, such as “lack of fill”, “abnormal stirring”, “surface galling”, and “excessive flash”, etc. As a result, the selectively-coupled shear localization model enables a theoretical estimation of FSW process window typically represented as a regime of welding speed and stir tool rotation speed combination for a given application, within which acceptable weld quality should be expected. Its application in FSW process window estimation is demonstrated by considering three types of aluminum alloys. In all cases, good agreements are achieved between model-estimated and experimentally-determined process windows. In addition, the proposed model also enables a theoretical estimation of optimum welding parameters within an established process window, e.g., for achieving maximum welding speed while maintaining good weld quality.

      PubDate: 2017-09-02T14:20:40Z
      DOI: 10.1016/j.ijmachtools.2017.08.003
      Issue No: Vol. 123 (2017)
       
  • Feasibility study of the novel quasi-elliptical tool servo for vibration
           suppression in the turning of micro-lens arrays
    • Authors: Zhiwei Zhu; Suet To; Wu-Le Zhu; Peng Huang
      Pages: 98 - 105
      Abstract: Publication date: November 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 122
      Author(s): Zhiwei Zhu, Suet To, Wu-Le Zhu, Peng Huang
      In fast or slow tool servo (F-/STS) diamond turning of micro-lens arrays (MLAs), the inherent non-smooth servo motion will lead to undesired tool vibrations, and it can significantly deteriorate the quality of the machined surface. Starting from a mathematical explanation of the underlying mechanism for vibration suppression, a quasi-elliptical tool servo (QETS) technique and the corresponding optimal toolpath determination algorithm are proposed to overcome the inherent defects in F-/STS turning of MLAs. As for the QETS, the inherent non-smooth servo motion in the F-/STS is proposed to be decomposed into two smooth quasi-harmonic motions along the cutting and servo motion directions, which then constructs the quasi-elliptical trajectory. Taking advantage of the smooth nature of the two decomposed motions, the undesired tool vibrations induced by the motion non-smoothness in the F-/STS can be significantly eliminated, accordingly facilitating the generation of MLAs with homogeneous and smooth surfaces. Finally, the new concept is verified through numerical simulation of the tool motion and experimental demonstration by turning a typical hexagonal aspheric MLA.

      PubDate: 2017-07-10T02:38:10Z
      DOI: 10.1016/j.ijmachtools.2017.06.004
      Issue No: Vol. 122 (2017)
       
  • Volumetric accuracy evaluation for five-axis machine tools by modeling
           spherical deviation based on double ball-bar kinematic test
    • Authors: Lei Zhong; Qingzhen Bi; Yuhan Wang
      Pages: 106 - 119
      Abstract: Publication date: November 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 122
      Author(s): Lei Zhong, Qingzhen Bi, Yuhan Wang
      This paper presents a new spherical deviation measurement method to evaluate the volumetric accuracy of five-axis machine tools based on double ball-bar measurements. Nine circular test paths with three kinds of tool axis directions in XY, YZ and ZX planes are planned to construct a typical sphere. The radial deviations measured by ball-bar are used to calculate the spherical deviation, which is defined as the maximum radial range of deviations around a least-squares sphere. Compared to the circular deviation described in ISO10791.6, which could only reflect the errors in one test path with one kinds of tool axis direction separately, the proposed method can reflect not only each test path's error, but also the offset errors between different test paths. And it could comprehensively quantify the effect of accuracies of the five axes together in three-dimensional space. The proposed method for five-axis machine tool can not only reflect the tool center position errors caused by three linear axes, but also indicate the tool axis direction errors caused by two rotary axes. The proposed method is verified through simulations and experiments on a five-axis machine tool.

      PubDate: 2017-07-10T02:38:10Z
      DOI: 10.1016/j.ijmachtools.2017.06.005
      Issue No: Vol. 122 (2017)
       
  • Identification of milling process damping using operational modal analysis
    • Authors: Min Wan; Jia Feng; Ying-Chao Ma; Wei-Hong Zhang
      Pages: 120 - 131
      Abstract: Publication date: November 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 122
      Author(s): Min Wan, Jia Feng, Ying-Chao Ma, Wei-Hong Zhang
      This paper provides a novel approach for identifying the process damping directly from chatter-free milling tests. First, power spectrum density matrix of cutter's deflections is theoretically derived by introducing transfer function and random excitation force, and the spectral decomposition of the power spectrum density matrix is formulated as an explicit function of modal parameters. Then, exponential attenuation method is adopted to extract the damping ratios from the inverse Fourier transformation result of the decomposed form. Finally, tangential and radial ploughing force coefficients, which are utilized to characterize process damping, are simultaneously calculated based on energy balance principle. Besides, experimental setup consisting of displacement sensors is specially designed to measure the cutter's deflections, which are further used to calculate the power spectrum density required in the above identification procedure. It is experimentally proven that the accuracy of chatter stability limits in milling process is improved when the proposed process damping model is considered.

      PubDate: 2017-07-10T02:38:10Z
      DOI: 10.1016/j.ijmachtools.2017.06.006
      Issue No: Vol. 122 (2017)
       
  • An intelligent wheel position searching algorithm for cutting tool grooves
           with diverse machining precision requirements
    • Authors: Guochao Li; Honggen Zhou; Xuwen Jing; Guizhong Tian; Lei Li
      Pages: 149 - 160
      Abstract: Publication date: November 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 122
      Author(s): Guochao Li, Honggen Zhou, Xuwen Jing, Guizhong Tian, Lei Li
      Searching for and adjusting to the appropriate wheel positions for designed grooves are among the key issues in the manufacturing of the end mill, drill and other integral cutting tools. Along with the increasing requirements of product categories and quality, a large number of non-traditional and customized grooves continuously appear. However, as multivariable, nonlinear and multiple target problems, it is difficult to obtain the desired wheel position. Therefore, we introduce an intelligent method to search for the optimum wheel position for the designed groove with the known wheel geometry. According to practice, the basic parameters of the groove and wheel geometries are introduced, and the problems studied in this paper are explained. As a foundation, a robust algorithm is built to predict machined grooves with a series of equal distribution points and three parameters: the rake angle, core radius and groove width. The influence that the wheel positions have on groove geometries is then analyzed. Then, an objective function considering different machining requirements is built, and the optimum wheel positions are searched for while the function is solved. Furthermore, an enhanced niche particle swarm optimization (NPSO) algorithm is developed to solve the problem. Finally, 6 experiments are carried out to verify and analyze the algorithm. The results show that the algorithm can effectively find the desired wheel positions according to different machining precision requirements.

      PubDate: 2017-07-23T10:02:56Z
      DOI: 10.1016/j.ijmachtools.2017.07.003
      Issue No: Vol. 122 (2017)
       
  • Identification of geometric errors of rotary axis on multi-axis machine
           tool based on kinematic analysis method using double ball bar
    • Authors: Hong-jian Xia; Wei-chao Peng; Xiang-bo Ouyang; Xin-du Chen; Su-juan Wang; Xin Chen
      Pages: 161 - 175
      Abstract: Publication date: November 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 122
      Author(s): Hong-jian Xia, Wei-chao Peng, Xiang-bo Ouyang, Xin-du Chen, Su-juan Wang, Xin Chen
      Accuracy identification of geometric errors of rotary axis is important for error compensation of the multi-axis machine tool. However, it is not easy because of the influence of setup error of measurement instrument, and there exists angular errors and displacement errors need to be identified simultaneously. In this paper, a decoupled method based on double ball bar is proposed to identify the geometric errors of rotary axis including both position independent geometric error (PIGE) and position dependent geometric error (PDGE). A formulation for ball bar measurement is derived from kinematic analysis to reveal the relationship between sensitivity direction and setup position of ball bar. The angular errors and displacement errors can be identified separately when choosing the appropriate setup position and direction of ball bar. It can effectively reduce the interaction influence between them and improve the accuracy. To identify the 4 PIGEs, a method by averaging the measured results of ball bar to compute the eccentricity and slant of rotary axis is proposed. And, the PDGEs are leaved to mainly describe the oscillation of geometric errors of rotary axis. It is useful to correct the deviation error resulting from setup error of ball bar. For the identification of 6 PDGEs, by means of adjusting setup position and direction of ball bar, they can be identified one by one along the sensitivity direction of ball bar. Furthermore, in order to reduce the influence of setup error of ball bar, the sensitivity analysis is performed to obtain the sensitivity of measured results of ball bar with respect to setup error. According to the sensitivity characteristics of setup error, a method is presented to correct the PDGEs. Finally, several numerical simulations and experiments are conducted to verify the theoretical model and the proposed identification method. The results from the simulations and experiments demonstrate that the method can identify the geometric errors of rotary axis effectively and accurately.

      PubDate: 2017-08-03T05:50:55Z
      DOI: 10.1016/j.ijmachtools.2017.07.006
      Issue No: Vol. 122 (2017)
       
  • Corrigendum to “Theoretical and experimental investigation of spindle
           axial drift and its effect on surface topography in ultra-precision
           diamond turning” [International Journal of Machine Tools &
           Manufacture 116 (2017) 107–113]
    • Authors: Quanhui Wu; Yazhou Sun; Wanqun Chen; Guoda Chen
      Pages: 176 - 178
      Abstract: Publication date: November 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 122
      Author(s): Quanhui Wu, Yazhou Sun, Wanqun Chen, Guoda Chen


      PubDate: 2017-09-02T14:20:40Z
      DOI: 10.1016/j.ijmachtools.2017.05.003
      Issue No: Vol. 122 (2017)
       
  • Special Issue on the State-of-the-Art in North American Manufacturing
           Research
    • Authors: Yusuf Altintas; Albert J. Shih; Tuğrul Özel
      First page: 1
      Abstract: Publication date: October 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 121
      Author(s): Yusuf Altintas, Albert J. Shih, Tuğrul Özel


      PubDate: 2017-07-23T10:02:56Z
      DOI: 10.1016/j.ijmachtools.2017.07.002
      Issue No: Vol. 121 (2017)
       
  • Mechanics of turn-milling operations
    • Authors: Alptunc Comak; Yusuf Altintas
      Pages: 2 - 9
      Abstract: Publication date: October 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 121
      Author(s): Alptunc Comak, Yusuf Altintas
      Turn-milling machines, which are capable of carrying out turning and milling operations, are widely used in machining complex parts in one set-up. However, due to the complex kinematics and tool-workpiece interaction, turn milling operations are mainly carried out by relying on costly machining trials and experience. This paper presents the mechanics of turn-milling operations to predict cutting forces, torque and power requirements. Typical turn milling process involves three linear (x,y.z) and two rotary drives of the machine tool. The resulting feed vector is modeled as a function of linear velocities of the drives, and angular speeds of workpiece and tool spindles. The generalized chip thickness distribution is modeled as a function of linear feed drive motions, tool and workpiece spindle rotations. The cutting force predictions are experimentally verified for sample cylindrical and ball end mills. The identification of productive tool and workpiece spindle speeds is demonstrated using chip load limit of the tools and torque-power constraints of the turn milling machine tools.

      PubDate: 2017-07-23T10:02:56Z
      DOI: 10.1016/j.ijmachtools.2017.03.007
      Issue No: Vol. 121 (2017)
       
  • Machined surface temperature in hard turning
    • Authors: Lei Chen; Bruce L. Tai; Rahul G. Chaudhari; Xiaozhong Song; Albert J. Shih
      Pages: 10 - 21
      Abstract: Publication date: October 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 121
      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 500–800°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: 2017-07-23T10:02:56Z
      DOI: 10.1016/j.ijmachtools.2017.03.003
      Issue No: Vol. 121 (2017)
       
  • Global tool-path smoothing for CNC machine tools with uninterrupted
           acceleration
    • Authors: Shingo Tajima; Burak Sencer
      Pages: 81 - 95
      Abstract: Publication date: October 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 121
      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: 2017-07-23T10:02:56Z
      DOI: 10.1016/j.ijmachtools.2017.03.002
      Issue No: Vol. 121 (2017)
       
  • Error Calibration of Controlled Rotary Pairs in Five-axis Machining
           Centers Based on the Mechanism Model and Kinematic Invariants
    • Authors: Zhi Wang; Delun Wang; Yu Wu; Huimin Dong; Shudong Yu
      Pages: 1 - 11
      Abstract: Publication date: Available online 20 April 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhi Wang, Delun Wang, Yu Wu, Huimin Dong, Yu Shudong
      The mechanism model of ball bar testing for a two-axis rotary table of 5-axis machining center is discussed, and a new ball bar method to measure the three-dimensional motions of the rotary pairs in multi-axis machining center is developed based on the mechanism model. Then, the fixed axes and moving axes of the rotary pairs are identified by using spherical image circle fitting and striction circle fitting, according to the kinematic invariants of nominal rotation and the measured motions. The structure errors and kinematic pair errors of the rotary pairs are defined and identified by using the fixed and moving axes, and the kinematic model of the two-axis rotary table is deduced with those errors. The simultaneous two-axis motions of the rotary table are measured to verify the proposed calibration method. The experimental results show good agreements with the predicted results calculated by the calibrated kinematic model. Furthermore, the accuracy of the simultaneous multi-axis motions of the machining center is improved when the identified errors are corrected.

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

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

      PubDate: 2017-04-10T11:54:27Z
      DOI: 10.1016/j.ijmachtools.2017.03.009
      Issue No: Vol. 118-119 (2017)
       
  • Effects of pin thread on the in-process material flow behavior during
           friction stir welding: A computational fluid dynamics study
    • Authors: Gaoqiang Chen; Han Li; Shuai Zhang; Qilei Dai; Xibo Wang; Gong Zhang; Qingyu Shi
      Abstract: Publication date: Available online 15 September 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Gaoqiang Chen, Han Li, Shuai Zhang, Qilei Dai, Xibo Wang, Gong Zhang, Qingyu Shi
      Pin thread is one of the most common geometrical features for the friction stir welding (FSW) tools. The main purpose of employing the pin thread is to improve the in-process material flow behaviors during FSW. However, it has not been fully understood how exactly the pin thread influences the material flow because of the lack of in-process observation. In this study, we aim to analyze the effect of pin thread on the in-process material flow during FSW of an AlMgZn alloy by using numerical simulation based on computational fluid dynamics (CFD). In our numerical simulation, the transient rotation of the threaded pin is implemented explicitly via fully transient control of the zone motion, and the mechanical interaction at the tool-workpiece interface is considered via the recent developed shear-stress-based frictional boundary condition. The numerical simulation has been validated by the experimental measured temperatures at 8 different locations, the distribution of marker materials and the geometry of deformation zone in the weld. Based on the numerical simulation results, three effects of the pin thread on the material flow have been elucidated. First, accelerated flow velocity and enhanced strain rate is induced owing to the use of the pin thread, which is attributed to the fact that the interfacial sticking is preferable inside the thread groove opening. Second, the pin thread has an effect to trap material in the high-velocity zone inside the thread groove opening, which causes a many-circle flow pattern around the threaded pin. Third, the pin thread contributes to a vertical pressure gradient, which is important for the in-process material transfer from the top to the bottom. The approaches and concepts in this study can be applied for further fundamental investigation of FSW and the computer aided design of the welding tools.

      PubDate: 2017-09-19T12:33:08Z
      DOI: 10.1016/j.ijmachtools.2017.09.002
       
  • A new physics-based model for equilibrium saturation determination in
           binder jetting additive manufacturing process
    • Authors: Hadi Miyanaji; Shanshan Zhang; Li Yang
      Abstract: Publication date: Available online 11 September 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Hadi Miyanaji, Shanshan Zhang, Li Yang
      In binder jetting additive manufacturing (BJ-AM) process, the features are created through the interaction between droplets of the liquid binding agent and the layered powder bed. The amount of binder, which is termed binder saturation, depends strongly on the liquid binder and powder bed interaction including the spreading (i.e. lateral migration) and penetration (vertical migration) of the binder in powder bed, and is of crucial importance for determining the accuracy and strength of the printed parts. In the present study, a new physics-based model is developed to predict the optimal saturation levels for the green part printing, which is realized via capillary pressure estimation that is based on the binder and powder bed interactions in the equilibrium state. The proposed model was evaluated by both the Ti6Al4V and 420 stainless steel powders that exhibit different powder characteristics and packing densities. In order to estimate the equilibrium saturation using the proposed model, the physical characteristics such as average contact angle between the binder and powder material, specific surface area of powder particles, saturation and capillary pressure characterization curve were determined. Features with various degrees of dimensions (1-D, 2-D, 3-D) were printed out using M-Lab ExOne printer for determining the equilibrium saturation. Good agreement was observed between the theoretical predictions and experimentally measured saturation levels for the Ti6Al4V powder. On the other hand, the model underestimated the optimal saturation level for the 420 stainless steel powder, which was likely caused by the micro-surface areas from powder particle surface that do not contribute to the binder-powder bed interactions.

      PubDate: 2017-09-13T12:25:14Z
      DOI: 10.1016/j.ijmachtools.2017.09.001
       
  • Multi-dimensional chatter stability for enhanced productivity in different
           parallel turning strategies
    • Authors: Milad Azvar; Erhan Budak
      Abstract: Publication date: Available online 1 September 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Milad Azvar, Erhan Budak
      Simultaneous turning with extra cutting edges increases the material removal rate (MRR), and thus the productivity of the process. On one hand, chatter could be a fatal threat to the productivity and part quality in simultaneous turning operations of slender and flexible workpieces. On the other hand, stability of flexible part turning can be increased significantly if the process parameters are selected properly. In practice, however, ensuring a stable parallel turning of a flexible workpiece is approached by the costly process of trial and error. In order to tackle this problem, a multi-dimensional model for chatter stability analysis of parallel turning operation is presented where the effects of components' dynamics, i.e. workpiece and cutters, in addition to insert's geometry are accounted for. The stability model is formulated for two configurations of the parallel turning operation in frequency and time domains, and verified experimentally. Chatter-free and high productivity cutting conditions are determined through optimal parameter selection employing stability maps generated for each configuration.

      PubDate: 2017-09-02T14:20:40Z
      DOI: 10.1016/j.ijmachtools.2017.08.005
       
  • An efficient error compensation method for coordinated CNC five-axis
           machine tools
    • Authors: Dan Zhao; Yunbo Bi; Yinglin Ke
      Abstract: Publication date: Available online 1 September 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Dan Zhao, Yunbo Bi, Yinglin Ke
      The paper introduces a new automatic drilling and riveting system for aircraft assembly which is composed of two five-axis machine tools in coordination. As a dual-machine system, relative position and orientation accuracy of coordinated machines is the decisive factor for high fastening quality. Considering all static/quasi-static error sources deteriorating relative positioning accuracy, an effective error compensation method which consists of a new error prediction model and an error compensation strategy is proposed for coordinated five-axis machines. Based on the decomposition concept, the coordinated workspace of dual machines is described as the superposition of the coordinated workspace of prismatic joints (CWP) and the coordinated workspace of revolute joints (CWR). They are separated to study the influence on the objective error, and a combined interpolation algorithm based on the shape functions is proposed for error prediction, which can avoid the curse of dimensionality essentially and be efficient to predict the relative position and orientation errors at any desired pose in the coordinated workspace of dual machines. For the error compensation of dual-machine system, a basic strategy is proposed which is to take the position and orientation of the driving machine as the reference and compensate the predicted error for the driven machine through the motion commands modification. To verify the feasibility of proposed method, experiments have been performed on the developed dual-machine system with different error compensation methods. The results show that the proposed method is more efficient which needs less time for sampled data measurement and calculation, and the relative positioning accuracy of the compensated dual-machine system is improved to 0.072 mm and 0.017° which meet the requirements for automatic drilling and riveting in aircraft assembly.

      PubDate: 2017-09-02T14:20:40Z
      DOI: 10.1016/j.ijmachtools.2017.08.007
       
  • Cutting temperature and resulting influence on machining performance in
           rotary ultrasonic elliptical machining of thick CFRP
    • Authors: Daxi Geng; Zhenghui Lu; Guang Yao; Jiajia Liu; Zhe Li; Deyuan Zhang
      Abstract: Publication date: Available online 1 September 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Daxi Geng, Zhenghui Lu, Guang Yao, Jiajia Liu, Zhe Li, Deyuan Zhang
      As a novel non-conventional machining process, rotary ultrasonic elliptical machining (RUEM) has been successfully used for drilling thick carbon fiber-reinforced plastics (CFRPs) recently. In order to reduce the thermal damage, the measurement of cutting temperature is important when RUEM of CFRP. In this research, the cutting temperatures in both RUEM and grinding drilling (GD) were measured by an infrared camera under dry condition. Temperature trends as functions of feed rate and cutting speed were obtained and the results showed that compared to GD, RUEM can effectively reduce the maximum temperature by 18.8% and 13.1% at the feed rate of 75 and 150 μm/rev respectively. Both mechanisms of temperature reduction and chip adhesion prevention in RUEM were analyzed. In addition, SEM observation of the machined surface revealed that better microstructure was obtained in RUEM compared to GD under the same cutting condition.

      PubDate: 2017-09-02T14:20:40Z
      DOI: 10.1016/j.ijmachtools.2017.08.008
       
  • Mechanics and multi-regenerative stability of variable pitch and variable
           helix milling tools considering runout
    • Authors: Jinbo Niu; Ye Ding; LiMin Zhu; Han Ding
      Abstract: Publication date: Available online 1 September 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jinbo Niu, Ye Ding, LiMin Zhu, Han Ding
      Variable pitch and variable helix (VPVH) milling tools are usually utilized to mitigate regenerative chatter vibrations by destroying the vibration phases between adjacent teeth. But this chatter suppression mechanism may considerably be disturbed by the inevitable tool runout, which could also change the phases, even to a larger extent. Thus the cutting performance of VPVH tools in terms of mechanics and dynamics should be re-evaluated by taking runout into consideration. This paper firstly sets up the mechanistic model for VPVH tools and then presents a combined nonlinear optimization procedure to identify the cutting coefficients and runout parameters. Secondly, the dynamic system of VPVH tools considering runout is modeled by a periodic-coefficient delay differential equation with multiple underdetermined delays. Afterwards, the generalized Runge-Kutta (GRK) method is extended to tackle the runout-induced multi-regenerative effects and thus to analyze the milling process stability. The accuracy and efficiency of the GRK method is validated using published numerical examples. A series of cutting experiments with a commercially available VPVH tool are performed to verify the presented mechanistic and dynamic models. It confirms that runout cannot be neglected when evaluating the cutting performance of VPVH tools. Finally, the joint influences of runout and pitch/helix angles on cutting forces and chatter stability of VPVH tools are discussed in detail based on the proposed approach.

      PubDate: 2017-09-02T14:20:40Z
      DOI: 10.1016/j.ijmachtools.2017.08.006
       
  • Flow behavior of powder particles in layering process of selective laser
           melting: Numerical modeling and experimental verification based on
           discrete element method
    • Authors: Hui Chen; Qingsong Wei; Shifeng Wen; Zhongwei Li; Yusheng Shi
      Abstract: Publication date: Available online 1 September 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Hui Chen, Qingsong Wei, Shifeng Wen, Zhongwei Li, Yusheng Shi
      Powder-layering is an essential process of selective laser melting (SLM), but the underlying mechanisms of powder movement and packing at particle scale is unclear. Based on discrete element method (DEM), this study proposed a numerical model to investigate the flowing behavior of powder layered by a blade, where the contact force and cohesion force between individual particles were considered. DEM simulations gave visual morphologies of the flow profiles and velocity fields for powder-layering at particle scale, as well as the relationships between the quality of powder bed and the layering parameters. The model was validated by experiment results in terms of the macroscopic profiles of powder during layering, showing good prediction accuracy. Then, dynamic repose angle (DRA) and mass flow rate (MFR) were defined to make quantitative evaluation on the powder flow. Preliminary research shows that, the powder fluidity increases with the decreasing of particle friction coefficients, resulting in a denser and more uniform powder bed. The decreasing of particle radius R over the range of R > 21.8 μm can benefit the powder fluidity. However, when the particle radius decreases in the range of R < 21.8 μm, the weight of cohesion force rises and thus makes the powder fluidity worse. The increase of layering speed enhances the dilation of moving particles, and the decrease of layering height intensifies the local force-arches in particles. These will reduce the continuity and stability of the powder flow and is unfavorable for improving the density or uniformity of the layered powder bed.
      Graphical abstract image

      PubDate: 2017-09-02T14:20:40Z
      DOI: 10.1016/j.ijmachtools.2017.08.004
       
  • An analytical local corner smoothing algorithm for five-axis CNC machining
    • Authors: Jixiang Yang; Alexander Yuen
      Abstract: Publication date: Available online 31 July 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jixiang Yang, Alexander Yuen
      Linear motion commands of computer numerical control (CNC) machine tools need to be smoothed at the transition corners in order to guarantee continuous and steady machining. However, because of the complex kinematic constraints, very few researches have devoted to developing analytical and high order continuous corner smoothing algorithms of five-axis tool paths, although it is important to guarantee both high calculation efficiency and good dynamic performance of five-axis CNC machining. This paper develops an analytical C 3 continuous corner smoothing algorithm of five-axis tool paths by locally inserting specially designed quintic micro splines into the transition corners of five-axis linear commands. C 3 continuity of the tool tip position and the tool orientation are guaranteed along the entire tool path. The maximal approximation errors of the tool tip position and the tool orientation are both constrained in the workpiece coordinate system. The synchronization of the tool tip position and tool orientation are mathematically guaranteed at the junctions of the linear and spline segments. The proposed corner smoothing algorithm can calculate all control points of the locally inserted tool tip position and tool orientation splines analytically without any iteration, which makes it very suitable to on-line calculation. Experiments on an in-house developed five-axis CNC platform verify that the maximal approximation errors of both tool tip position and tool orientation are constrained, and the proposed C 3 continuous corner smoothing algorithm has higher tracking accuracy and lower acceleration frequency content at higher frequencies than the C 2 continuous algorithm.

      PubDate: 2017-08-03T05:50:55Z
      DOI: 10.1016/j.ijmachtools.2017.07.007
       
  • Theoretical and experimental study of magnetic-assisted finish cutting
           ferromagnetic material in WEDM
    • Authors: Zhi Chen; Yanming Zhang; Guojun Zhang; Yu Huang; Chunhua Liu
      Abstract: Publication date: Available online 30 July 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhi Chen, Yanming Zhang, Guojun Zhang, Yu Huang, Chunhua Liu
      A method of magnetic assisted finish cutting ferromagnetic material is proposed to improve machining performance in WEDM, and theoretical and experimental study of this method is implemented to illustrate its improving mechanism. Firstly, the motion trajectory model of electron beam is presented for the first time to clarify the effect of constant magnetic field on increasing the discharge crater in single pulse discharge process, and theoretical model and experiment indicate that additional constant magnetic field can efficiently suppress the divergence phenomenon, increase energy density of electron beam and shorten discharge gap breakdown time. Secondly, the charged debris motion curve of magnetic assisted finish cutting is worked out, and it reveals that more charged debris can be washed away when the direction of Lorentz force is the same with dielectric flushing. Additionally, a set of experiment is accomplished to investigate the improving effect of constant magnetic field, and experiment result represents that significantly improvement (material removal rate (MRR) maximum increase by 44.0%, and surface roughness (Ra) maximum reduce by 30.5%) has been obtained. Eventually, by the method of multi-objective optimization, a group of Pareto optimal set of MRR and Ra is worked out to satisfy different requirement of practical manufacture.

      PubDate: 2017-08-03T05:50:55Z
      DOI: 10.1016/j.ijmachtools.2017.07.009
       
  • A multiscale evaluation of the surface integrity in boring trepanning
           association deep hole drilling
    • Authors: Huang Zhang; Xingquan Shen; Arixin Bo; Yaoming Li; Haifei Zhan; Yuantong Gu
      Abstract: Publication date: Available online 23 July 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Huang Zhang, Xingquan Shen, Arixin Bo, Yaoming Li, Haifei Zhan, Yuantong Gu
      Boring trepanning association (BTA) deep hole drilling is one of the most important manufacturing techniques to produce a large length-to-diameter ratio hole for industrial applications. In addressing the challenge of excessive surface damage, inefficiency and poor indexing in BTA deep hole drilling, for which there are limited studies reported. The functional behaviour of deep hole machining and the correlation between the machined surface quality, subsurface layer deformation and the machining conditions are investigated in this paper, together with the drilling mechanism. Various parameter combinations are used to produce different samples on which surface roughness and microstructures are studied. Metallurgical characterization is performed on the subsurface regions, followed by qualitative and quantitative mechanical nanohardness investigations. Electron microscopic analysis reveals various surface features such as grooves and plateaus, folding, material flaking that are exclusive to deep hole drilling. It has been found that improved surface integrity in BTA drilling relies on a trade-off among feedrates and speeds. Although considered sample dependent, combination of a feedrate of 28 mm min−1 and a speed of 630 r min−1 can produce nearly excellent surface integrity. Grain structure observations over the subsurface reveal three different layered zones including an ultrafine grain structure layer, a transitional grain structure layer and a substrate material layer. A significantly hardened (56% increase) surface layer on cutting-and-burnishing region comparing with the solely cutting region is detected. The subsurface grain features are induced by repeated thermo-mechanical functioning that causes grain refinement and thus materials hardening. The different surface integrities are the result of comprehensive functions of the machining parameters and combined drilling mechanism.

      PubDate: 2017-08-03T05:50:55Z
      DOI: 10.1016/j.ijmachtools.2017.07.005
       
  • State-of-the-art in fixture systems for the manufacture and assembly of
           rigid components: A review
    • Authors: A. Gameros; S. Lowth; A. Dragos; A. Nagy-Sochacki; O. Craig; H.R. Siller
      Abstract: Publication date: Available online 22 July 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): A. Gameros, S. Lowth, A. Dragos, A. Nagy-Sochacki, O. Craig, H.R. Siller
      Basic work holding devices (e.g. vices), fixtures and jigs are used to construct a critical interface between a workpiece and an end-effector. This interface performs two main functions: location of the workpiece in the Euclidean space and preservation of the workpiece position against any loads. Despite the critical nature of the part-machine interface, limited attention has been given to work holding systems in the academic community. In this respect, the main objective of this paper is to systematically review the field of fixture design, thus allowing the classification of fixturing systems to identify research trends and niches. This review is broken into four sections: (i) basics of fixturing and work holding; (ii) fixtures for single components. The classification of these systems is based on an evolutionary trend that allows to see how the development of technologies, such as additive manufacture, sensing technologies and actuation systems, affects fixture design; (iii) fixtures for multi-parts (both for batch production and assembly operations), with an emphasis on the unique challenges that arise from the assembling process; and (iv) conclusions, denoting various research trends/opportunities in the areas of fixture design and fixture instrumentation. Examples of these prospects includes the integration of fixtures with sensing technology (incentivise by the growth of industry 4.0) and the construction of truly new multi-part fixturing systems, rather than just the expansion of single component fixtures.

      PubDate: 2017-08-03T05:50:55Z
      DOI: 10.1016/j.ijmachtools.2017.07.004
       
  • IFC - Editorial board
    • Abstract: Publication date: October 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 121


      PubDate: 2017-07-23T10:02:56Z
       
  • Study on position of laser cladded chip breaking dot on rake face of HSS
           turning tool
    • Authors: Chenchun Shi; Aibing Yu; Jianzhao Wu; Weiyang Niu; Yuan He; Xin Hong; Quanbo Shang
      Abstract: Publication date: Available online 6 July 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Chenchun Shi, Aibing Yu, Jianzhao Wu, Weiyang Niu, Yuan He, Xin Hong, Quanbo Shang
      Chip breaker with a raised dot was fabricated on the rake face of high speed steel (HSS) turning tool using laser powder cladding method. Based on chip breaking condition and chip breaking dot position conditions, three position equations of laser cladded chip breaking dot were established. The theoretical position regions of laser cladded chip breaking dot on rake face of tool were determined. Turning experiments of aluminum alloy were carried out. Chip breaking processes were observed with high-speed camera. The calculated position regions of chip breaking dot are in good agreement with the experimental results. Turning tool with chip breaking dot located in the position region on rake face has effective chip breaking ability. There also exists a transition position region of chip breaking dot. The position regions could provide reference for the fabrication of laser cladded chip breaking dot on rake face of HSS cutting tools.

      PubDate: 2017-07-10T02:38:10Z
      DOI: 10.1016/j.ijmachtools.2017.07.001
       
  • IFC - Editorial board
    • Abstract: Publication date: September 2017
      Source:International Journal of Machine Tools and Manufacture, Volume 120


      PubDate: 2017-06-28T03:43:51Z
       
  • Grinding performance of textured monolayer CBN wheels: Undeformed chip
           
    • Authors: Wenfeng Ding; Chenwei Dai; Tianyu Yu; Jiuhua Xu; Yucan Fu
      Abstract: Publication date: Available online 13 June 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Wenfeng Ding, Chenwei Dai, Tianyu Yu, Jiuhua Xu, Yucan Fu
      The ground surface roughness and topography are commonly used to characterize the surface finishing. In the application of textured monolayer CBN wheels, the nonuniformity of wheel topology will render a nonuniform undeformed chip thickness which greatly affects the ground surface. In order to predict the ground surface topography more accurately and efficiently, grinding experiment has been conducted in the current study, with measured grinding wheel topology. The measured surface topology of textured monolayer CBN wheels have been reconstructed by using the Johnson transformation and its inverse transformation. The influence of wheel topology evolution on the undeformed chip thickness nonuniformity has been determined with an improved model. It has been found the ground surface roughness is improved with a continuous reducing undeformed chip thickness nonuniformity. The percentage of active grains, the mean value and standard deviation of undeformed chip thickness have been found the main factors in determining the surface roughness. The reconstructed wheel surface topology has been used to predict the workpiece topography in different stages of the grinding process.

      PubDate: 2017-06-15T13:23:09Z
      DOI: 10.1016/j.ijmachtools.2017.05.006
       
  • Analysis of grinding mechanics and improved predictive force model based
           on material-removal and plastic-stacking mechanisms
    • Authors: Yanbin Zhang; Changhe Li; Heju Ji; Xiaohui Yang; Min Yang; Dongzhou Jia; Xianpeng Zhang; Runze Li; Jun Wang
      Abstract: Publication date: Available online 13 June 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Yanbin Zhang, Changhe Li, Heju Ji, Xiaohui Yang, Min Yang, Dongzhou Jia, Xianpeng Zhang, Runze Li, Jun Wang
      Numerous researchers have developed theoretical and experimental approaches to force prediction in surface grinding under dry conditions. Nevertheless, the combined effect of material removal and plastic stacking on grinding force model has not been investigated. In addition, predominant lubricating conditions, such as flood, minimum quantity lubrication, and nanofluid minimum quantity lubrication, have not been considered in existing force models. This work presents an improved theoretical force model that considers material-removal and plastic-stacking mechanisms. Grain states, including cutting and ploughing, are determined by cutting efficiency (β). The influence of lubricating conditions is also considered in the proposed force model. Simulation is performed to obtain the cutting depth (a g) of each “dynamic active grain.” Parameter β is introduced to represent the plastic-stacking rate and determine the force algorithms of each grain. The aggregate force is derived through the synthesis of each single-grain force. Finally, pilot experiments are conducted to test the theoretical model. Findings show that the model's predictions are consistent with the experimental results, with average errors of 4.19% and 4.31% for the normal and tangential force components, respectively.

      PubDate: 2017-06-15T13:23:09Z
      DOI: 10.1016/j.ijmachtools.2017.06.002
       
  • Maximum undeformed equivalent chip thickness for ductile-brittle
           transition of zirconia ceramics under different lubrication conditions
    • Authors: Min Yang; Changhe Li; Yanbin Zhang; Dongzhou Jia; Xianpeng Zhang; Yali Hou; Runze Li; Jun Wang
      Abstract: Publication date: Available online 13 June 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Min Yang, Changhe Li, Yanbin Zhang, Dongzhou Jia, Xianpeng Zhang, Yali Hou, Runze Li, Jun Wang
      This study investigates the critical maximum undeformed equivalent chip thickness for ductile-brittle transition (DBh max-e ) of zirconia ceramics under different lubrication conditions. A DBh max-e model is developed through geometry and kinematics analyses of ductile-mode grinding. Result shows that DBh max-e decreases with increasing friction coefficient (μ). An experimental investigation is then conducted to validate the model and determine the effect of dry lubrication, minimum quantity lubrication (MQL), and nanoparticle jet minimum quantity lubrication (NJMQL) conditions on DBh max-e . According to different formation mechanisms of debris, the grinding behavior of zirconia ceramics is categorized into elastic sliding friction, plastic removal, powder removal, and brittle removal. Grinding forces per unit undeformed chip thickness (F n/h and F t/h ) are obtained. The lubrication condition affects the normal force and ultimately influences the resultant force on workpiece. In comparison with dry grinding (DBh max-e  = 0.8 μm), MQL and NJMQL grinding processes increase DBh max-e by 0.99 and 1.79 μm respectively; this finding is similar to model result. The theoretical model is then assessed by different volume fractions of nanofluids under NJMQL condition with an average percentage error of less than 8.6%.

      PubDate: 2017-06-15T13:23:09Z
      DOI: 10.1016/j.ijmachtools.2017.06.003
       
  • Formation of uniform metal traces using alternate droplet printing
    • Authors: Jun Luo; Wenqiang Wang; Wei Xiong; He Shen; Lehua Qi
      Abstract: Publication date: Available online 10 June 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jun Luo, Wenqiang Wang, Wei Xiong, He Shen, Lehua Qi
      Formation of uniform traces is fundamental, but challenging, in droplet-based 3D printing. Due to the scalloped surface topography of metal droplets and complex thermal deformation between them, sequentially printed traces tend to form low-quality shapes. Here, an alternate droplet printing method is proposed to print uniform metal traces. Instead of printing droplets successively, discrete droplet array with uniform intervals was first printed. Then, the gaps between droplets were fully filled up in a later printing iteration. Herein, the proper combination of the step interval and the thermal state in the droplet printing process were first investigated to ensure the success of the proposed printing method. Four typical shapes of segments were identified using multiple three-droplet deposition experiments. Moreover, metal trace printing experiments further revealed five distinct trace topographies. In addition, the relationship between the topographies of printed traces and the printing parameters (i.e., temperature of the substrate and printing step size) was studied to establish a trace-shape map. Finally, experiments show that metal traces with the dimensionless roughness (Ra/D d ) of 1.8% were successfully printed. The results demonstrate a significant reduction of the roughness comparing to the literature results printed in consecutive sequence.

      PubDate: 2017-06-11T07:22:58Z
      DOI: 10.1016/j.ijmachtools.2017.05.004
       
  • Virtual pivot alignment method and its influence to profile error in
           bonnet polishing
    • Authors: Junkang Guo; Anthony Beaucamp; Soichi Ibaraki
      Abstract: Publication date: Available online 6 June 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Junkang Guo, Anthony Beaucamp, Soichi Ibaraki
      This paper proposes a measurement and adjustment procedure for virtual pivot errors using the R-test and investigates the influence of virtual pivot errors to the surface profile in bonnet polishing. Initially, kinematic modeling is carried out for describing the location errors of rotary axes and defining overall errors of the virtual pivot arm. Then, the R-test is introduced to measure the three-dimensional displacement of a sphere located at the virtual pivot point and identify location errors. The adjustment procedure for virtual pivot errors is developed by means of mathematical analysis. The measurement and adjustment approach is applied to an ultra-precision polishing machine, on which an adjustment experiment was conducted to validate the proposed method. Based on this, a contrastive polishing experiment on a concave lens is carried out under good and poor virtual pivot errors. The experiment result shows that the maximum form deviation of the polished surface profile is reduced from 241.0 nm to 89.6 nm when good alignment of virtual error is achieved. Analytical simulation based on a material removal model of the bonnet polishing tool and machine is implemented to reveal the influence of virtual pivot errors to polishing quality.

      PubDate: 2017-06-11T07:22:58Z
      DOI: 10.1016/j.ijmachtools.2017.06.001
       
  • Energy distribution modulation by mechanical design for electrochemical
           jet processing techniques
    • Authors: Jonathon Mitchell-Smith; Alistair Speidel; Jennifer Gaskell; Adam T. Clare
      Abstract: Publication date: Available online 31 May 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jonathon Mitchell-Smith, Alistair Speidel, Jennifer Gaskell, Adam T. Clare
      The increasing demand for optimised component surfaces with enhanced chemical and geometric complexity is a key driver in the manufacturing technology required for advanced surface production. Current methodologies cannot create complex surfaces in an efficient and scalable manner in robust engineering materials. Hence, there is a need for advanced manufacturing technologies which overcome this. Current technologies are limited by resolution, geometric flexibility and mode of energy delivery. By addressing the fundamental limitations of electrochemical jetting techniques through modulation of the current density distribution by mechanical design, significant improvements to the electrochemical jet process methods are presented. A simplified 2D stochastic model was developed with the ability to vary current density distribution to assess the effects of nozzle-tip shape changes. The simulation demonstrated that the resultant profile was found to be variable from that of a standard nozzle. These nozzle-tip modifications were then experimentally tested finding a high degree of variance was possible in the machined profile. Improvements such as an increase in side-wall steepness of 162% are achieved over a standard profile, flat bases to the cut profile and a reduction of profile to surface inter-section radius enable the process to be analogous to traditional milling profiles. Since electrode design can be rapidly modified EJP is shown to be a flexible process capable of varied and complex meso-scale profile creation. Innovations presented here in the modulation of resistance in-jet have enabled electrochemical jet processes to become a viable, top-down, single-step method for applying complex surfaces geometries unachievable by other means.
      Graphical abstract image

      PubDate: 2017-06-01T13:16:43Z
      DOI: 10.1016/j.ijmachtools.2017.05.005
       
  • Prediction of surface roughness in abrasive waterjet trimming of fiber
           reinforced polymer composites
    • Authors: J. Schwartzentruber; J.K. Spelt; M. Papini
      Abstract: Publication date: Available online 25 May 2017
      Source:International Journal of Machine Tools and Manufacture
      Author(s): J. Schwartzentruber, J.K. Spelt, M. Papini
      Surface roughness is a valuable metric when assessing abrasive waterjet machining (AWJM) cut quality. This paper presents 2D and 3D models capable of predicting the surface roughness during abrasive waterjet (AWJ) trimming of composite substrates. The composites used were a carbon-fiber laminate with an epoxy resin and a random oriented carbon-fiber/vinyl ester. The models were based on an earlier rigid-plastic erosive particle indentation model capable of predicting crater sizes using the particle impact and substrate properties. In the 2D model, single particle impact craters were aligned to form multi-particle impact profiles that were iteratively superimposed until a steady-state surface roughness was achieved. The 3D model generated conical craters that were individually superimposed until a steady-state surface roughness was achieved. The models were capable of predicting the surface roughness with an average error of 10% and 16%, for the 2D and 3D models, respectively. The models show that the surface roughness decreased with an increase in particle velocity, a decrease in kerf taper, and an increase in the dynamic hardness of the target.

      PubDate: 2017-05-27T08:40:38Z
      DOI: 10.1016/j.ijmachtools.2017.05.007
       
  • IFC - Editorial board
    • Abstract: Publication date: August 2017
      Source:International Journal of Machine Tools and Manufacture, Volumes 118–119


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

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

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

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

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

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

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

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

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

      PubDate: 2017-04-10T11:54:27Z
      DOI: 10.1016/j.ijmachtools.2017.04.004
       
  • 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
       
 
 
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