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  Subjects -> MANUFACTURING AND TECHNOLOGY (Total: 283 journals)
    - CERAMICS, GLASS AND POTTERY (25 journals)
    - MACHINERY (32 journals)
    - MANUFACTURING AND TECHNOLOGY (175 journals)
    - METROLOGY AND STANDARDIZATION (3 journals)
    - PACKAGING (15 journals)
    - PAINTS AND PROTECTIVE COATINGS (5 journals)
    - PLASTICS (27 journals)
    - RUBBER (1 journals)

MACHINERY (32 journals)

Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9)
Advanced Energy Materials     Hybrid Journal   (Followers: 18)
Applied Mechanics Reviews     Full-text available via subscription   (Followers: 24)
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: 8)
Engenharia Agrícola     Open Access  
High Speed Machining     Open Access   (Followers: 1)
High Temperature Materials and Processes     Hybrid Journal   (Followers: 5)
International Journal of Machine Tools and Manufacture     Hybrid Journal   (Followers: 6)
International Journal of Machining and Machinability of Materials     Hybrid Journal   (Followers: 5)
International Journal of Manufacturing Technology and Management     Hybrid Journal   (Followers: 9)
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: 1)
Journal of Machinery Manufacturing and Automation     Open Access   (Followers: 3)
Journal of Mechanics     Hybrid Journal   (Followers: 17)
Journal of Strain Analysis for Engineering Design     Hybrid Journal   (Followers: 6)
Journal of Terramechanics     Hybrid Journal   (Followers: 1)
Machine Design     Partially Free   (Followers: 43)
Machines     Open Access   (Followers: 2)
Materials     Open Access   (Followers: 6)
Mechanics Based Design of Structures and Machines: An International Journal     Hybrid Journal   (Followers: 3)
Micromachines     Open Access   (Followers: 3)
Practical Machinery Management for Process Plants     Full-text available via subscription  
Pump Industry Analyst     Full-text available via subscription  
Russian Engineering Research     Hybrid Journal  
Sensor Review     Hybrid Journal   (Followers: 1)
Surface Engineering and Applied Electrochemistry     Hybrid Journal   (Followers: 7)
Journal Cover International Journal of Machine Tools and Manufacture
  [SJR: 3.363]   [H-I: 81]   [6 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0890-6955
   Published by Elsevier Homepage  [2801 journals]
  • Generalized mechanics and dynamics of metal cutting operations for unified
           simulations
    • Abstract: Publication date: May 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 104
      Author(s): Z.M. Kilic, Y. Altintas
      This paper presents the unified modeling of mechanics and dynamics of metal cutting operations such as turning, boring, drilling and milling. The distribution of chip thickness along the cutting edges of tools are evaluated using the generalized geometric and kinematic model of the operations [1]. The effect of relative vibrations between the cutting edge and workpiece segments are considered. The force contributed by each oblique cutting edge segment is evaluated from shear stress, shear angle and friction coefficient defined in orthogonal cutting data base. The tool cutting loads are evaluated by summing the differential cutting forces along all engaged cutting edges using the generalized geometric transformations presented in [1]. The chatter stability is solved in modal coordinate system, and the forced vibration marks left on the finish surface are predicted in discrete time domain. The process damping, multiple-regenerative phase delays which depend on the tool geometry and operations are considered. The application of the proposed unified mechanics and dynamics model is demonstrated experimentally in drilling, milling with indexable cutters and various end mills, and in opening large holes with multi-functional drilling/boring heads.


      PubDate: 2016-02-08T04:29:35Z
       
  • Study on cutting force model in ultrasonic vibration assisted side
           grinding of zirconia ceramics
    • Abstract: Publication date: Available online 27 January 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Xingzhi Xiao, Kan Zheng, Wenhe Liao, Heng Meng
      Ultrasonic vibration assisted side grinding (UVASG) has outstanding performance in machining hard-and-brittle materials, such as ceramics. The cutting force is the key factor that affects the machined surface/subsurface quality, which has been investigated both experimentally and theoretically. However, the combined effect of both ductile removal and brittle fracture removal on cutting force model in UVASG of ceramics has not been reported yet. In this study, a theoretical cutting force model is proposed with the consideration of the ductile-to-brittle transition removal mechanism in UVASG of ceramics. The critical cutting depth of ductile-to-brittle transition has been determined experimentally to distinguish the ductile region and brittle region. Besides, the average cutting depths have been derived for the modeling of the cutting forces in ductile and brittle region, respectively. Then the number of active diamond grits has been presented for the development of the final cutting force model. The parameter K is introduced to represent the influence of overlapping and intersection between different diamond grits. In addition, the relationship between cutting force and input variables has been revealed through the model. Finally, the pilot experiments are conducted to verify the theoretical model. The experimental results are consistent well with the model predictions. Therefore, the theoretical model can be applied to evaluate the cutting force, and it can provide better understanding of the effects of ductile removal and brittle fracture removal on the cutting force during UVASG of ceramics.


      PubDate: 2016-01-29T13:13:47Z
       
  • Comment on “ A novel approach for the prediction of the milling
           stability based on the Simpson method” By Z. Zhang, H. Li, G. Meng
           and C. Liu, International Journal of Machine Tools & Manufacture
           99 (2015) 43–47
    • Abstract: Publication date: Available online 20 January 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): C.G. Ozoegwu



      PubDate: 2016-01-23T01:43:34Z
       
  • Generalized modelling of cutting tool geometries for unified process
           simulation☆
    • Abstract: Publication date: Available online 22 January 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Z.M. Kilic, Y. Altintas
      This paper presents a generalized geometric model of cutting tools for the purpose of predicting the mechanics and dynamics of machining operations. The model starts by defining the tangent and rake face vectors at discrete elements along the cutting edge. The discrete cutting edge elements are assembled mathematically to form either an insert or solid cutting edge, which are further transformed to design turning, boring, drilling, milling and other tools by considering the geometry and kinematics of cutting operations. Homogeneous transformation matrices are used to successively locate and orient the cutting edge within the insert, tool and process coordinate frames. Industry-standard tool-in-use planes are used to obtain the effective geometry for all cutting operations. In total 15 geometric parameters are used for identifying the geometry of an arbitrary tool. Radial and axial runouts are considered in the model. Generalized model is demonstrated by modelling the geometry of sample drills, indexable and serrated milling tools. The generalized model allows unified prediction of machining operations with one mathematical model which covers all operations and tool geometries.


      PubDate: 2016-01-23T01:43:34Z
       
  • Material removal mechanism in ultrasonic vibration assisted polishing of
           micro cylindrical surface on SiC
    • Abstract: Publication date: Available online 15 January 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Qingliang Zhao, Zhiyuan Sun, Bing Guo
      In consideration of the high hardness of the mold insert material SiC, ultrasonic vibration was introduced in the abrasive polishing (AP) of the linear micro cylindrical surface aiming to enhance the surface quality while improving the machining efficiency. However, the interaction behavior in between the material and polishing tool under ultrasonic vibration has not been studied so far. In this paper, the material removal mechanism of ultrasonic vibration assisted polishing (UVAP) on micro cylindrical SiC surface was investigated to fulfill a fundamental understanding of this process in comparison to the conventional polishing without employing ultrasonic vibration. The collection method of high frequency friction forces was firstly proposed to analyze the friction behavior on the SiC cylindrical surface. Then the relationship between ultrasonic vibration, friction force and micro cylindrical surface quality was studied respectively. The experimental results indicated that when the ultrasonic vibration was applied, the friction force decreased accordingly corresponding to a better surface quality. In addition, the lubrication condition was discussed in UVAP process based on the establishment of the stribeck curve. Furthermore, the wear coefficients were calculated through measuring the material removal depth, the surface morphologies were measured by a scanning electron microscopy in revealing the different material removal modes under various different polishing parameters. Through computation and analysis, it shows that the lower polishing force and relative lower speed as well as the higher vibration frequency and amplitude could result in a lower surface roughness and less polishing marks of micro cylindrical surface on SiC. Finally, the cylindrical arrays were successfully polished with the optimized parameters on precision diamond ground SiC surfaces.


      PubDate: 2016-01-19T04:53:09Z
       
  • IFC - Editorial board
    • Abstract: Publication date: March 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 102




      PubDate: 2016-01-19T04:53:09Z
       
  • Mechanics of fibre deformation and fracture in vibration-assisted cutting
           of unidirectional fibre-reinforced polymer composites
    • Abstract: Publication date: Available online 15 January 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Weixing Xu, Liangchi Zhang
      Fibre orientation significantly affects the surface integrity of the machined fibre-reinforced polymer (FRP) composites. Crushing or bending-dominated fibre fracture in the machining of FRPs is governed by fibre orientation relative to the cutting direction. This paper revealed the mechanics behind such phenomena and developed a reliable predictive model for cutting FRPs. The analysis integrated the effect of the whole fibre orientation range from 0° to 180°. Both traditional cutting and elliptic vibration-assisted (EVA) cutting of unidirectional FRPs were analysed by integrating microstructure-based and equivalent homogeneous deformation zones. A systematic experiment was also carried out. A comprehensive comparison of the mechanics predictions with the experiments shows that the model has captured the major material removal mechanisms and can be used to predict fibre deformation, fibre-matrix debonding, fibre fracture, subsurface damage and cutting forces in both traditional and vibration-assisted cutting. It was identified that fibre orientation affects subsurface damage and cutting forces significantly, and that EVA cutting can minimize the orientation effect. There is a critical fibre orientation at which subsurface damage and cutting force in feed direction would reach their worst situations.


      PubDate: 2016-01-19T04:53:09Z
       
  • A review of fly cutting applied to surface generation in ultra-precision
           machining
    • Abstract: Publication date: Available online 6 January 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): S.J. Zhang, S. To, Z.W. Zhu, G.Q. Zhang
      Fly cutting in ultra-precision machining (UPM), termed ultra-precision fly cutting (UPFC), is an intermittent cutting process in which a diamond tool is mounted with a spindle to intermittently cut a workpiece. The process offers the high flexibility necessary for fabricating freeform, micro/nano-structural surfaces, as well as hybrid structural surfaces with sub-micrometric form error and nanometric surface roughness, and its constant cutting velocity provides uniform high surface quality. However, in addition to its low machining efficiency, UPFC’s intermittent cutting process results in distinctive surface generation mechanisms, covering intermittent tool-workpiece relative motion, tool geometry imprinted into a machined surface, and surface material separation and deformation. General factors, such as cutting conditions, tool geometry, material factors (material property change, material swelling and recovery, and material separation mechanism), kinematic and dynamic errors, assembling errors, cutting strategies, tool path, and workpiece geometry, are individual to UPFC and universal in UPM. Accordingly, this paper focuses on the current investigation of fly cutting applied into surface generation in UPM. Conclusions are reached and the challenges and opportunities for further studies are discussed.
      Graphical abstract image

      PubDate: 2016-01-07T09:50:35Z
       
  • On chip formation of bone orthogonal cutting mechanism
    • Abstract: Publication date: Available online 1 January 2016
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhirong Liao, Dragos A. Axinte
      Bone cutting is an important procedure in most surgery operations; therefore, understanding the mechanism by which the chip forms is important to design tools for optimising the surgery process. However, only very few studies to address this issue exist. In this paper, a transition from shear cutting, shear-crack cutting and fracture cutting modes with the increase of uncut chip thickness in orthogonal bone cutting was presented. To address these phenomena, a fracture mechanics based cutting model was proposed for the chip formation and cutting process. The influence of the anisotropy of bone to the orthogonal cutting was studied in reference to chip formation and thus, considered in the model to explain the chip morphologies in different cutting directions relative to the bone fibres (i.e. osteon). The experimental result shows to be consistent well with the proposed model yielding a maximum error of predicted transition uncut chip thickness of 10%. On the other hand, analysis of surface morphology revealed that significant differences exist in material damage mode related to the cutting mode and direction. Moreover, the proposed bone orthogonal cutting mechanism was also validated by the cutting force analysis from both static and dynamic components points of view. Based on this study, a maximum uncut chip thickness in a unique anisotropic material as bone to guide the selection of more advanced cutting process (e.g. drilling, milling and sawing) was proposed.


      PubDate: 2016-01-03T09:35:52Z
       
  • An accurate prediction method of cutting forces in 5-axis flank milling of
           sculptured surface
    • Abstract: Publication date: Available online 31 December 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Xing Zhang, Jun Zhang, Bo Pang, WanHua Zhao
      The instantaneous uncut chip thickness and entry/exit angle of cutter/workpiece engagement continuously vary with tool path and workpiece geometry in 5-axis flank milling of sculptured surface, which results in the obvious time-varying characteristic for consecutive cutting forces. An accurate prediction method for cutting force in 5-axis flank milling of sculptured surface is proposed in this paper. Comprehensively considering curved tool path and actual tool motion process with cutter runout (offset and inclination) effects, an accurate representation model for instantaneous uncut chip thickness during cutter/workpiece engaging in 5-axis flank milling is presented firstly, which can reach a higher accuracy and efficiency with the aid of linear iteration process than the methods published. Then, based on the thin plate milling experiments, an efficient calibration procedure for cutter runout parameters and specific cutting force coefficients is given and further verified in practice. Finally, a series of validation experiments are conducted under different cutting conditions, and the results reveal that there is a very good agreement between the experimental and simulation data both in shape and magnitude and prove the effectiveness and accuracy of the proposed method.


      PubDate: 2016-01-03T09:35:52Z
       
  • A ballbar test for measurement and identification the comprehensive error
           of tilt table
    • Abstract: Publication date: Available online 24 December 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jian-xiong Chen, Shu-wen Lin, Xiao-long Zhou, Tian-qi Gu
      This paper proposes a comprehensive geometric error measurement and identification method for a tilt table equipped in a five-axis machine tool with two turntables using the double ballbar. Three positional errors of the socket, caused by both the volumetric error and linkage error of the tilt table, are measured in the sensitive directions with simple circular paths. A mathematics model is applied to map the relationship between the night results that are from three installation positions of the socket and all the errors of the tilt table. Firstly, all the measured results are applied to establish the average axis that is just with the linkage error of the tilt table using the newly developed circular fitting method, rather than solving the large-scale linear equations. Then, the linkage error is treated as the trend item in the measured results for it keeps constant during the rotation of the tilt table. Hence, the volumetric error is identified by the remaining part of the measured results, which are obtained by subtracting the part caused by the linkage error, using the pseudo invert matrix method. Meanwhile, an error model is established to analyze the influence of the installation errors of the socket and the tool cup. Two simple correction procedures, using a low-cost electron clamp and an easily operated circular path, are developed to eliminate these two installation errors before the ballbar test. Finally, a verification experiment, by comparing the predicted value from the identified errors with the measured results by the ballbar, is carried out to validate the effectiveness and correctness of the proposed method.


      PubDate: 2015-12-26T04:45:57Z
       
  • IFC - Editorial board
    • Abstract: Publication date: February 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 101




      PubDate: 2015-12-18T08:10:12Z
       
  • Investigation of pulse electrochemical sawing machining of micro-inner
           annular groove on metallic tube
    • Abstract: Publication date: Available online 11 December 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): G.X. Liu, Y.J. Zhang, S.Z. Jiang, J.W. Liu, G.K. Gyimah, H.P. Luo
      Pulse electrochemical sawing micro-machining (PECSM) is a non-conventional process. Having features of no tool wear, no cutting force, and good surface quality, this process is suitable for machining micro-grooves on the inner wall of hole. The rotating dentate cathode (RDC) is beneficial for the distribution of electrolyte and electrolytic products removal, thus reducing the effects of concentration polarization on the electrochemical reaction. This study focuses on the PECSM of micro-inner annular groove on 304 stainless steel tube using a pH-neutral NaClO3 electrolyte. To study the effects of RDC on the process, the bubble layer structure (BLS) adhered to the surface of RDC was photographed using a high-speed camera. Under the condition of immersion, the symmetric distribution of two kinds of BLS adhered to the RDC surface. The four selected parameters (radius of dentate cathode, rotational speed of RDC, initial gap, feed rate) with different levels were carried out to study the process of PECSM micro-inner annular grooves on 304 stainless steel tube. Experimental results indicate that PECSM has high potential for machining micro-inner annular groove on metallic tube. A micro-inner annular groove that is 340μm in depth and 263μm in width was fabricated on a 304 stainless steel tube.


      PubDate: 2015-12-14T04:20:08Z
       
  • Surface generation of freeform surfaces in diamond turning by applying
           double-frequency elliptical vibration cutting
    • Abstract: Publication date: Available online 30 November 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Xiaoqin Zhou, Chengming Zuo, Qiang Liu, Jieqiong Lin
      A new freeform surface generation method for the difficult-to-cut materials is proposed in this paper. Fast tool servo and slow slide servo diamond turning are the main generation technologies for freeform surfaces, whereas they cannot machine the freeform surfaces of difficult-to-cut materials very effectively. On the other hand, elliptical vibration cutting has demonstrated its excellent performance in material processing, especially for the difficult-to-cut materials. Nevertheless, it is unable to generate the freeform surfaces very successfully. Therefore, this paper proposes the double-frequency elliptical vibration cutting method for the freeform surface diamond machining on the difficult-to-cut materials, which provides the high-frequency elliptical vibration to improve the machinability in material removal and the low-frequency reciprocating movements for the freeform surface profile generation. The relative movements between the tool and the workpiece are analyzed, and because of the Y direction elliptical vibration, the cutting plane does not always cross the workpiece center, which makes the tool path generation, the tool geometry selection and the surface topography prediction very different from those in the conventional fast tool servo or slow slide servo diamond turning. A new tool path generation method is proposed, and the selection of the tool geometry parameters is discussed. The surface generation process is analyzed, based on which the topography model for the machined surfaces is constructed. Three typical freeform surfaces are machined on the die steel workpieces, which verifies the feasibility of the proposed tool path generation strategies. In addition, the experimental results agree well with the surface topography predictions, which validates the effectiveness of the topography model. This model also applies to the diamond turning processes with tool motion in the Y direction, such as turning with EVC.


      PubDate: 2015-12-04T08:09:40Z
       
  • Modeling and compensation of volumetric errors for five-axis machine tools
    • Abstract: Publication date: Available online 1 December 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Sitong Xiang, Yusuf Altintas
      This article proposes a method to measure, model and compensate both geometrically dependent and independent volumetric errors of five-axis, serial CNC machine tools. The forward and inverse kinematics of the machine tool are modeled using the screw theory, and the 41 errors of all 5 axes are represented by error motion twists. The component errors of translational drives have been measured with a laser interferometer, and the errors of two rotary drives have been identified with ballbar measurements. The complete volumetric error model of a five-axis machine has been modeled in the machine's coordinate system and proven experimentally. The volumetric errors are mapped to the part coordinates along the tool path, and compensated using the kinematic model of the machine. The compensation strategy has been demonstrated on a five-axis machine tool controlled by an industrial CNC with a limited freedom, as well as by a Virtual CNC which allows the incorporation of compensating all 41 errors.


      PubDate: 2015-12-04T08:09:40Z
       
  • A new approach to improving the machining precision based on dynamic
           sensitivity analysis
    • Abstract: Publication date: Available online 2 December 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Liping Zhao, Hongren Chen, Yiyong Yao, Guangzhou Diao
      This paper proposes a new approach to improving the machining precision based on dynamic sensitivity analysis. Firstly, the movement transmission chain of machine tools is analyzed to establish the error propagation model. The model can be used to calculate the error sensitive coefficient of each component. Secondly, the deformation of each component is acquired depending on the finite element analysis. Combining the error sensitive coefficient and deformation, the sensitive error components of machine tools are identified. Thirdly, according to the sensitive error components, the layout of the machine tool is modified and the stiffness of sensitive error component is improved to reduce the machining error of machine tools. A simulation example about globoidal cam machine tools is conducted. Comparing the machining error of vertical globoidal cam machine tool and horizontal globoidal cam machine tool in the simulation, the feasibility of the method is verified. This method not only increases the stiffness of the sensitive error component, but also changes the layout of the machine tool based on dynamic sensitivity analysis results. Therefore, it can provide a new approach to improving the machining accuracy. Finally, an experiment was conducted to verify the validity the correctness of the conclusions.


      PubDate: 2015-12-04T08:09:40Z
       
  • Vibration analysis and suppression in robotic boring process
    • Abstract: Publication date: Available online 27 November 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Yingjie Guo, Huiyue Dong, Guifeng Wang, Yinglin Ke
      The industrial robot, due to its flexibility, is considered as a promising option to accomplish the fine boring work of the aircraft intersection holes. However, the robot has a relatively low stiffness and is easily subjected to chatter vibration in the boring process, resulting in difficulty in guaranteeing the machining quality. In this article, the mechanism of the vibration in the robotic boring process is analyzed, and a novel vibration suppression method based on the pressure foot is proposed. First, a robotic boring system is presented. Based on its cutting characteristics and stiffness characteristics, the mechanism of the vibration is analyzed, followed by the study of the tool path during the boring operation. It is found that in the robotic boring process it is the robot itself vibrates rather than the boring bar, which usually vibrates in the traditional CNC machine tools. And the type of the vibration is found to be a forced vibration with a displacement feedback. Furthermore, a novel method making use of the pressure foot is proposed to suppress the vibration of the robot. Finally, large numbers of boring experiments have been conducted and the results verify the correctness of the vibration mechanism and the effectiveness of the vibration suppression method.


      PubDate: 2015-11-30T00:17:29Z
       
  • Correlation between preload and no-load drag torque of ball screws
    • Abstract: Publication date: Available online 27 November 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Chang-Guang Zhou, Hu-Tian Feng, Zeng-Tao Chen, Yi Ou
      This paper examines the relationship between the preload and no-load drag torque of ball screws. Based on a new equation to calculate the normal contact load between balls and the screw raceway under no external load, a new correlation between preload and no-load drag torque is proposed. Meanwhile, a novel preload-adjustable ball screw mechanism and a drag torque measuring system are constructed. Three LCM300 load cells and a force sensor are implemented for obtaining the experimental data from the constructed systems. Preload and no-load drag torque are obtained and analyzed. It is found that there is a large gap between the calculated preload by traditional formula and the measured value. The experimental results, agreeing well with the theoretical values calculated in this paper, show there exists a linear correlation between preload and drag torque in a preloaded ball screw mechanism. Furthermore, the derivation of the drag torque would be decreased when increasing the preload, which can improve the stability of the screw during its operation. This study provides an accurate correlation to obtain the preload through the no-load drag torque for preloaded ball screws, which is significant for better performance of ball screws as well as the CNC machine tools.


      PubDate: 2015-11-30T00:17:29Z
       
  • Real Time Parameter Based Contour Error Estimation Algorithms for Free
           Form Contour Following
    • Abstract: Publication date: Available online 28 November 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Hung-Ruey Chen, Ming-Yang Cheng, Chun-Hsien Wu, Ke-Han Su
      The contour following task of a multi-axis servo system is one of the most important applications of modern Computer Numerical Control (CNC) machine tools, and is widely seen in many types of CNC machining. Hence, the reduction of contour error occurring in the contour following process is paramount and deserves more comprehensive investigation. In general, the calculation of precise contour error in real time is very challenging if not impossible, in free-form curve following tasks. To deal with such a problem, this paper proposes six real-time contour error estimation methods for free-form parametric curves. The feasibility of these methods is verified with several NURBS parametric curve contour following experiments. In addition, experimental results reveal that the proposed methods can provide more accurate contour error estimation for various free-form curves than the other estimation algorithms tested in the experiments. With the proposed contour error estimation approach, advanced motion control schemes can be designed to efficiently reduce contour errors of contour following tasks.


      PubDate: 2015-11-30T00:17:29Z
       
  • Micro-patterning technique using a rotating cutting tool controlled by an
           electromagnetic actuator
    • Abstract: Publication date: February 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 101
      Author(s): JongHyun Kim, Sun-Kyu Lee
      This work describes a micro-patterning or surface texturing technique on the fixed work surface using a proposed new spindle system with a rotating cutting tool controlled in real time. The proposed spindle system creates micro-sized patterns using rotating tools such as a micro-milling tool and a micro-grinding wheel. The shaft of the spindle is suspended by air bearings, and an electromagnetic actuator controls the radial motion of the spindle housing instead of the shaft. This generates a micro-pattern array on the electro-less Ni-coated workpiece in the micro-milling process. A PID controller is adopted to make the system stable, and adaptive feedforward cancellation is used to effectively compensate for the run-out of the spindle system during machining. The machining results show that this compensation improves the pattern accuracy. It is expected that micro-patterning using the proposed spindle system can be applied over a large surface area.


      PubDate: 2015-11-26T12:33:05Z
       
  • Hybrid Additive and Subtractive Machine Tools-Research and Industrial
           Developments
    • Abstract: Publication date: Available online 22 November 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Joseph M. Flynn, Alborz Shokrani, Stephen T. Newman, Vimal Dhokia
      By synergistically combining additive and subtractive processes within a single workstation, the relative merits of each process may be harnessed. This facilitates the manufacture of internal, overhanging and high aspect ratio features with desirable geometric accuracy and surface characteristics. The ability to work, measure and then rework material enables the reincarnation and repair of damaged, high-value components. These techniques present significant opportunities to improve material utilisation, part complexity and quality management in functional parts. The number of single platform workstations for hybrid additive and subtractive processes (WHASPs) is increasing. Many of these integrate additive directed energy deposition (DED) with subtractive CNC machining within a highly mobile multi-axis machine tool. Advanced numerical control (NC), and computer aided design (CAD), manufacture (CAM) and inspection (CAI) help to govern the process. This research reviews and critically discusses salient published literature relating to the development of WHASPs, and identifies future avenues for research and development. It reports on state-of-the-art WHASP systems, identifying key traits and research gaps. Finally, a future vision for WHASPs and other hybrid machine tools is presented based upon emerging trends and future opportunities within this research area


      PubDate: 2015-11-26T12:33:05Z
       
  • IFC - Editorial board
    • Abstract: Publication date: January 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 100




      PubDate: 2015-11-21T04:11:47Z
       
  • Feasibility study of the ultrasonic vibration filing of carbon fiber
           reinforced silicon carbide composites
    • Abstract: Publication date: February 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 101
      Author(s): Yan Wang, Vinod K. Sarin, Bin Lin, Huan Li, Scott Gillard
      In this paper, ultrasonic vibration filing (UVF) is considered as a new method for inner surface machining of deep cavity component, which is made of carbon fiber reinforced silicon carbide composites (C/SiC). The mathematical models obtained by kinematics analysis are taken out to reveal the machining principle of UVF. The surface formation mechanism is explained by surface residual height theory. The surface roughness, machining force and the surface microstructure are investigated and compared between UVF, common filing (CF) and common grinding (CG). It can be found that different grain size has a large influence on the surface morphology, which indicated the machining quality could be improved by control of the grain size. Ultrasonic vibration amplitude is considered as the most important ultrasonic parameter in UVF, it has a big influence on surface quality and machining force. According to the research, UVF is an effective machining method for inner shape processing of deep cavity workpiece, as well as improving the topography of the machined surface. Compared with traditional machining methods, UVF have an obviously improvement in surface quality and shape precision.


      PubDate: 2015-11-13T09:34:57Z
       
  • Polymer/CeO2-Fe3O4 multicomponent core–shell particles for
           high-efficiency magnetic-field-assisted polishing processes
    • Abstract: Publication date: Available online 6 November 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Junji Murata, Yoshihito Ueno, Koushi Yodogawa, Takahito Sugiura
      Novel multicomponent core–shell particles have been developed for use in high-efficiency magnetic-field-assisted polishing processes. The core–shell particles consist of core polymer particles covered by a shell composed of magnetic particles and abrasive grains. The particle preparation process involves agitation of the particle mixture in a dry ambient atmosphere with an appropriate controlled temperature, which is a simple and low-cost technique compared with the conventional sintering and granulation process used for the preparation of magnetic abrasives. Although the prepared polymer/CeO2-Fe3O4 multicomponent core–shell particles exhibit inferior glass-polishing performance compared to CeO2 abrasives without an applied magnetic field, they reveal a markedly higher removal rate in the presence of the magnetic field than that exhibited by conventional abrasives and mixed compounds (Fe 3 O 4 and CeO 2 ). Furthermore, polishing using the core–shell particles with the magnetic field shows the potential to achieve a superior material surface quality compared to conventional polishing.
      Graphical abstract image

      PubDate: 2015-11-08T22:04:27Z
       
  • Feed fluctuation of ball screw feed systems and its effects on part
           surface quality
    • Abstract: Publication date: Available online 3 November 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Tao Liang, Dun Lu, Xiaojun Yang, Jun Zhang, Xiaobo Ma, Wanhua Zhao
      Feed fluctuation plays an important role on the part surface quality during the precision machining. In this paper, an analytical electromechanical model is developed to reveal the essential characteristics of the feed fluctuation for ball screw feed system, where the feedback control and driving circuit are equivalent to a “controlled current-source” and the mechanical transmission is modeled as a two-mass system. The analytical expression of displacement fluctuation is deduced and then the characteristics of feed fluctuation are investigated. Finally the influence of feed fluctuation on machining quality is analyzed. The results show that when the frequency of torque ripple is closer to the natural frequency of feed systems, the amplitude of displacement fluctuation increases significantly while that of the torque ripple has a sharp decrease. The displacement fluctuation along the feed direction contributes to the bright and dark stripes on the surface of workpiece in a precise cylindrical turning.


      PubDate: 2015-11-04T22:03:13Z
       
  • Parametric chip thickness model based cutting forces estimation
           considering cutter runout of five-axis general end milling
    • Abstract: Publication date: Available online 4 November 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zerun Zhu, Rong Yan, Fangyu Peng, Xianyin Duan, Lin Zhou, Kang Song, Chaoyong Guo
      In the process of sculpture surfaces machining, due to the changes of the cutter orientation and the inevitable eccentricity between tool and spindle, machining parameters optimization based on five-axis cutting force is quite a challenge. To solve this problem, this study proposes a new method, cutting edge element moving(CEEM) method, to calculate instantaneous undeformed chip thickness(IUCT), to distinguish cutter/workpiece engagement(CWE) area and to simulate five-axis machining cutting force considering runout for general end mills. On the basis of upper work, the parameter representation of IUCT is deduced by the parametric expression of coordinate transformation matrix and feed vector, and resolved to three sub models about tool orientation, tool orientation change and cutter runout. At last, cutting force coefficients and cutter runout parameters are calibrated by cutting test and dial gauge testing. And inclined axis cutting test for bull nose mill, cylinder face-milling test for ball end mill and conical surface flank milling test for flat end mill are carried out to verify the effectiveness of the proposed model and related decomposition model. Combined with the specific test, some analysis about peak values, mean values and peak to peak difference values of cutting forces in various tool orientations are conducted, and the effect to cutting force from the changes of lead and tilt angles are evaluated. Some conclusions obtained and the methods utilized can be used to optimize tool orientation and feed rate etc.


      PubDate: 2015-11-04T22:03:13Z
       
  • Suppression of the Inflection Pattern in Ultraprecision Grinding through
           the Minimization of the Hydrodynamic Force using a Toothed Wheel
    • Abstract: Publication date: Available online 28 October 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Yeon Hwang, Gyu Ha Kim, Young-Bok Kim, Jeong-Ho Kim, Sun-Kyu Lee
      Fluid coolant has been widely used for cooling, lubrication, and the removal of cutting chips in the grinding process; however, it can generate grinding marks due to the hydrodynamic force especially in case of a lack of the spindle stiffness. This leads to inflection patterns on the workpiece, with sub-micrometer level of waviness, which is quite critical in rotationally symmetric ultraprecision grinding. In this study, we propose the use of a toothed wheel which is remarkably efficient in suppressing the inflection pattern by minimizing the hydrodynamic pressure. A toothed wheel has a simple geometry with a peripheral surface similar to a saw. The teeth disturb the generation of the coolant flux layer and noticeably decrease the hydrodynamic force. Furthermore, the toothed wheel increases the net grinding force due to the tangential cutting edge. This study simulated the hydrodynamic pressure in the grinding process and validated the flat surface grinding results by varying the tooth geometry. A comparison showed that the hydrodynamic force was decreased by 20–35% and that the inflection pattern of the ground surface was markedly decreased in rotational symmetric grinding.


      PubDate: 2015-10-31T21:44:46Z
       
  • Effect of Dynamic Recrystallization at Tool-Chip Interface on Accelerating
           Tool Wear during High-Speed Cutting of AISI1045 Steel
    • Abstract: Publication date: Available online 24 October 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): C.L. Pu, G. Zhu, S.B. Yang, E.B. Yue, S.V. Subramanian
      Acceleration of tool crater wear in high-speed cutting is usually attributed to the high tool–chip interface temperature increasing diffusion coefficient( D E f f ), where the role of microstructure is ignored. The main purpose of this paper is to study the influence of microstructure evolution at second shear zone on tool element diffusion ability and crater wear with increasing cutting speed, which establishes the base for the research of tool wear evolution forecast. Based on the Orthogonal turning experiment of AISI1045 steel, the effect of cutting speed( V ) on crater wear and microstructure of second shear zone was notable: (1)the crater wear increased drastically at 361mmin−1< V < 560mmin−1, in which the change to lower or higher cutting speed was relatively flat; (2)the images obtained by field-emission scanning electron microscopy showed dramatically microstructure evolution occurred at second shear zone, and extremely refined dynamic recrystallization grain, with 80nm to 300nm grain size, was formed as cutting speed increased. The very fine dynamic recrystallization grain significantly increased the fraction of high-diffusion channel (grain boundary area), and thus the diffusion coefficient was enhanced. Based on this idea, the impact of dynamic recrystallization grain, coupled with tool–chip interface temperature calculated by Oxley model, on diffusion coefficient was explored by Hart equation. The analysis has shown that the influence of dynamic recrystallization grain on tool crater wear was significant by increasing D E f f .


      PubDate: 2015-10-28T07:21:53Z
       
  • A study on droplets sizes, their distribution and heat exchange for
           minimum quantity cooling lubrication (MQCL)
    • Abstract: Publication date: Available online 26 October 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Radoslaw W. Maruda, Grzegorz M. Krolczyk, Eugene Feldshtein, Franci Pusavec, Michal Szydlowski, Stanislaw Legutko, Agnieszka Sobczak-Kupiec
      The paper analyses the influence of emulsion mist formation parameters and the nozzle distance from the tool–chip interface, on the droplet velocity at the nozzle outlet, on active medium atomization angle as well as on the diameter and number of droplets supplied to the cutting zone. The deformation coefficient of the droplets falling on the surface and the wetting angle have also been determined. In the work it has been proved that the strongest influence on the droplets diameter have the air flow and the distance of the nozzle from the cutting zone. It has been shown that larger angle of the stream splitting ensures that the droplets do not join each other in the air, and consequently assures small diameter on the surface. Additionally, the results show that the emulsion mass flow does not change the droplets diameters by more than 12%. It has been determined that smaller the droplets diameter is, higher content of active compounds in the tribofilms formed on the machined surface is present. In this way the paper presents the analysis and directions of MQCL adjustment trends needed to improve the machining performance.


      PubDate: 2015-10-28T07:21:53Z
       
  • Theoretical modelling and FE simulation on the oblique diamond turning of
           ZnS crystal
    • Abstract: Publication date: January 2016
      Source:International Journal of Machine Tools and Manufacture, Volume 100
      Author(s): W.J. Zong, Z.M. Cao, C.L. He, C.X. Xue
      In diamond turning of Cleartran ZnS crystal, the input cutting parameters have significant influences on the appearance of pit or crack defects on the finished surface. Therefore, a novel oblique cutting model is developed in this work to improve the surface quality of Cleartran ZnS crystal, in which a crack-free surface is supposed to be finished in a brittle–ductile coupled mode. And subsequently, fly-cutting experiments are performed to find the brittle–ductile transition depth of Cleartran ZnS substrates, which is employed to qualitatively determine the critical uncut chip thickness and predict the critical cutting parameters, including depth of cut, tool feed rate and rake angle. Moreover, a 3D finite element cutting model of Cleartran ZnS crystal is also constructed by using the nanoindentation test and dimensional analysis method, with which the crack propagation in chip formation can be simulated. In such a way, the predicted critical cutting parameters can be validated by the cutting experiments and finite element simulation. The results show that the oblique cutting process is an effective approach to relax the critical cutting parameters and reduce the shear stress ahead of tool cutting edge, which in return heavily suppresses the crack propagation and grain breakage. As a result, the achieved surface quality is improved.


      PubDate: 2015-10-28T07:21:53Z
       
  • Modeling the dependency of edge chipping size on the material properties
           and cutting force for rotary ultrasonic drilling of brittle materials
    • Abstract: Publication date: Available online 22 October 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jianjian Wang, Pingfa Feng, Jianfu Zhang, Chenglong Zhang, Zhijian Pei
      Edge chipping induced by rotary ultrasonic drilling (RUD) restricts the applications of brittle materials. It should be possible to reduce or eliminate edge chipping by optimizing the process parameters based on efficient theoretical modeling of the size of the edge chip. However, to date, no publications are available on the predictive modeling of edge chipping during RUD of brittle materials. This paper presents an analytical model for predicting the edge chipping size during RUD of brittle materials by considering both effects of cutting force and subsurface cracks induced by machining on the occurrence of edge chipping. The relationships between the edge chipping size, processing variables (material properties and ultrasonic amplitude), and the cutting force were established theoretically. The coefficients in the model were obtained by conducting RUD tests on K9 optical glass specimens. Subsequently, the model was validated by conducting RUD tests on sapphire specimens. Using this model, the edge chipping size can be predicted during RUD of brittle materials. The experimental and predicted results were in good agreement.
      Graphical abstract image

      PubDate: 2015-10-23T08:55:54Z
       
  • A uniform expression model for volumetric errors of machine tools
    • Abstract: Publication date: Available online 23 October 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhenya He, Jianzhong Fu, Hongyao Shen, Xianmin Zhang
      This paper proposes a new method, a Self-adaptive Mathematical Expression Model (SMEM), to describe volumetric errors of machine tools based on Non-Uniform Rational B-Spline (NURBS). The NURBS parameters of expression model were optimized by an improved Genetic Algorithm (GA). Simulation method was adopted to verify the effectiveness of the parameter optimization method of the SMEM, and the measurement experiment and machining experiment with error compensation based on the SMEM were conducted on a five-axis machining center with a titling rotary table. It was found that the SMEM can be used to uniformly express the position-dependant error parameters. Compared with the traditional methods, which adopt largely discrete database tables or polynomial method, the presented method is more concise, accurate and robust. In addition, volumetric errors of any position among the workspace of the machine tools can be quickly obtained by searching the SMEM of error parameters. And volumetric error of tool paths and the actual surface of the machining parts also can be expressed by the SMEM. The accuracy of the linear measured paths can have a great improvement of 70.63% with error compensation based on the SMEM. The accuracy of the part's predicted machining precision using the SMEM was 76.34%, and the surface profile error of the part can be improved significantly, up to 61.29%, when the SMEM was used for error compensation. Therefore, the expression model established in this study is feasible and robust, and could be used to express error parameters and volumetric errors. Moreover, it could be used to predict machining precision of part before machining and provide the basis for error compensation.


      PubDate: 2015-10-23T08:55:54Z
       
  • IFC - Editorial board
    • Abstract: Publication date: December 2015
      Source:International Journal of Machine Tools and Manufacture, Volume 99




      PubDate: 2015-10-19T08:42:00Z
       
  • Mechanism for changes in cutting forces for down-milling of unidirectional
           carbon fiber reinforced polymer laminates: Modeling and experimentation
    • Abstract: Publication date: Available online 13 October 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Satoru Maegawa, Yuta Morikawa, Shinya Hayakawa, Fumihiro Itoigawa, Takashi Nakamura
      In this study, a new cutting model for the machining of unidirectional CFRP laminates was developed to examine the mechanism for changes in the cutting forces with tool wear. This model is based on Zhang's model and divides the cutting zone into two characteristic deformation regions; chipping and pressing. Furthermore, CFRP milling tests were performed using two kinds of cutting tools: tungsten carbide (WC–Co) and polycrystalline diamond (PCD). Based on the experimental results with the developed cutting model, the net cutting forces to make a cut chip and press CFRP laminates under the flank surface of the tool were quantitatively evaluated. Consequently, it was found that the former does not depend on the progress of the tool wear, but the later increases with tool wear. Additionally, based on the results in this study, a new technique for reducing cutting forces during CFRP machining, which is based on the use of two layer tool that has a wear resistance distribution at around the tool edge was introduced.


      PubDate: 2015-10-15T11:31:43Z
       
  • State-of-the-art in surface integrity in machining of nickel-based super
           alloys
    • Abstract: Publication date: Available online 13 October 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): A. Thakur, S. Gangopadhyay
      Nickel-based super alloys are gaining more significance, now-a-days, with extensive applications in aerospace, marine, nuclear reactor and chemical industries. Several characteristics including superior mechanical and chemical properties at elevated temperature, high toughness and ductility, high melting point, excellent resistance to corrosion, thermal shocks, thermal fatigue and erosion are primarily responsible for wide domain of application. Nevertheless, machined surface integrity of nickel-based super alloys is a critical aspect which influences functional performance including fatigue life of the component. This review paper presents state-of-the-art on various surface integrity characteristics during machining of nickel-based super alloys. Influence of various cutting parameters, cutting environment, coating, wear and edge geometry of cutting tools on different features of surface integrity has been critically explained. These characteristics encompass surface roughness, defects (surface cavities, metal debris, plucking, smeared material, redeposited material, cracked carbide particles, feed marks, grooves and laps), metallurgical aspects in the form of surface and sub-surface microstructure phase transformation, dynamic recrystallization and grain refinement and mechanical characteristics such as work hardening and residual stress. Microstructural modification of deformed layer, profile of residual stresses and their influence on fatigue durability has been given significant emphasis. Future research endeavour might focus on development of new grades, advanced processing techniques of the same to ensure their superior stability of microstructure and thermo-mechanical properties along with advanced manufacturing processes like additive manufacturing to achieve highest level of fatigue durability of safety critical components while maintaining acceptable surface integrity and productivity.


      PubDate: 2015-10-15T11:31:43Z
       
  • Identification of different geometric error models and definitions for the
           rotary axis of five-axis machine tools
    • Abstract: Publication date: Available online 9 October 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Shuang Ding, Xiaodiao Huang, Chunjian Yu, Xiangyu Liu
      Geometric errors are the major error sources of machine tools. Different geometric error models have been used in published studies according to the different definitions of geometric errors of the rotary axis. This is considerably dangerous as it makes the definition of geometric errors ambiguous and may reduce the effect of geometric error identification and compensation. This phenomenon has not been noticed yet. In this paper, another two used geometric error models of rotary axis are firstly introduced and analyzed, named as “Error first model” and “Motion first model”, respectively. These two models were both verified correctly by an example. After a detailed comparison, errors identified with these two models are discovered to have a certain relationship. “Error first model” is preferred for the modeling and definition of geometric errors of rotary axis. An experiment has been conducted on a 5-axis machine tool to demonstrate the correctness of our research. The results show that the identified geometric errors of rotary axis according to the two error models are greatly different and deserved to be concerned.


      PubDate: 2015-10-10T18:38:36Z
       
  • Influence of thermodynamics within molten pool on migration and
           distribution state of reinforcement during selective laser melting of
           AlN/AlSi10Mg composites
    • Abstract: Publication date: Available online 9 October 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Donghua Dai, Dongdong Gu
      A transient three dimensional model for describing the thermo-capillary convection and migration behavior and the resultant distribution state of reinforcing particles during selective laser melting of AlN/AlSi10Mg is proposed. The powder-solid transformation, temperature dependent physical properties and interaction between the reinforcement and the melt are taken into account. The effect of the laser energy per unit length (LEPUL) on the molten pool dynamics, cooling rate and the resultant sizes and distribution state of AlN reinforcement has been investigated. It shows that the thermo-capillary convection pattern changes from inward flow pattern to outward one, due to the appearance of the oxidation in molten pool. Therefore, the morphology of the top surface undergoes a continuous variation from the balling phenomenon, to the discontinuous tracks and finally to the formation of a flat and dense one. Meanwhile, both the clockwise and counterclockwise convection patterns are produced in the molten pool, caused by the interaction of reinforcing particles and the melt. An increase in LEPUL will significantly intensify the thermo-capillary convection whereas result in a decrease in the cooling rate of the molten pool. As LEPUL decreases from 1800J/m to 450J/m, the distribution state of AlN particles changes from the severe aggregation, then to the formation of partial aggregation and finally to the homogeneous distribution in the solidified matrix. The particle sizes of AlN reinforcement are experimentally acquired, which are in a good agreement with the results predicted by simulation.


      PubDate: 2015-10-10T18:38:36Z
       
  • IFC - Editorial board
    • Abstract: Publication date: November 2015
      Source:International Journal of Machine Tools and Manufacture, Volume 98




      PubDate: 2015-10-03T03:58:32Z
       
  • The linear inverse problem in energy beam Processing with an application
           to abrasive waterjet machining
    • Abstract: Publication date: Available online 10 September 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): A. Bilbao Guillerna, D. Axinte, J. Billingham
      The linear inverse problem for energy beam Processing, in which a desired etched profile Is known and a trajectory of the beam that will create it must be found, Is studied in this paper. As an example, abrasive waterjet machining (AWJM) Is considered here supported by extensive experimental investigations. the behaviour of this process can be described using a linear model when the Angle between the jet and the surface Is approximately constant during the process, as occurs for shallow etched profiles. the inverse problem Is usually solved by simply controlling dwell time in proportion to the required depth of milling, without considering whether the target surface can actually be etched. to address this, a Fourier analysis Is used to show that High frequency components in the target surface cannot be etched due to the geometry of the jet and the dynamics of the machine. in this paper, this frequency domain analysis Is used to improve the choice of the target profile in such a way that it can be etched. the dynamics of the machine also have a large influence on the actual movement of the jet. it Is very difficult to describe this effect because the controller of the machine Is usually unknown. a simple approximation Is used for the choice of the slope of a step profile. the tracking error between the desired trajectory and the real one Is reduced and the etched profile Is improved. several experimental tests are presented to show the usefulness of this approach. Finally, the limitations of the linear model are studied.


      PubDate: 2015-09-13T11:06:06Z
       
  • The interlayer gap and non-coaxiality in stack drilling
    • Abstract: Publication date: Available online 10 September 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Yuhao Gao, Dan Wu, Chenggen Nan, Xinguo Ma, Yunfei Dong, Ken Chen
      Interlayer gap formation during through-hole drilling in stacked structures is a common problem in large assembly operations. The resulting interfacial burrs and non-coaxial stacked holes deteriorate the machining quality and increase the overall assembly time and costs. This study presents both experimental work and theoretical analysis to understand the interlayer gap formations and non-coaxiality occurrences in the drilling of stacked structures of broad skins and narrow stringers, which imitate typical structures of large assemblies. First, some stack drilling experiments are specially designed and are performed to observe that the stacked holes are non-coaxial in a regular fashion by measuring the hole diameters of the upper layer, lower layer and interface. Then, a simplified mechanical model of the stacks is built in 2-D to study how the interlayer gaps and non-coaxiality are formed during stack drilling. Through quantitative analysis based on the simplified model, it is noted that the stack stiffness, drilling thrust force and pressing force have important impact on the interlayer gaps and non-coaxiality. Finally, finite element methods are adopted to present the deformations in 3-D. The calculation results agree with the theoretical explanations for non-coaxiality given by the analytical simplified model. In addition, the beneficial effects of the fasteners and ribs are discussed based on the calculation results, and thus, they could contribute to proposals for better designs for stack drilling.
      Graphical abstract image

      PubDate: 2015-09-13T11:06:06Z
       
  • Improving Machined Surface Textures in Avoiding Five-Axis Singularities
           Considering Tool Orientation Angle Changes
    • Abstract: Publication date: Available online 3 September 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhiwei Lin, Jianzhong Fu, Xinhua Yao, Yangfan Sun
      This paper looks into the irregular machined surface textures appearing in the process of avoiding five-axis singularities using the C-space based tool orientation translation method. At first, the mechanism for the appearances of the irregular surface textures is analyzed. A cutting simulation in VERICUT reveals that irregular surface textures are actually caused by lacking control of the tool orientation angles in the orientation modification process. Realizing that, a modified particle swarm optimization (PSO) is intergraded into the previous tool orientation translation method. In the PSO, the particle evolving equations are redefined and a mutation operation is added. The objective of the PSO is to find an optimal translating vector in the C-space so that the changed tool orientation angles can reach minimum values. In this way, the surface textures can be controlled. Three comparative cutting experiments with fillet endmills are carried out to verify the effect of the proposed method. The experimental results show that: (1) with the tool orientation translation method, the five-axis singular problem can be well avoided; and (2) with the optimal translating vector found by the PSO, the machined surface textures can be greatly improved.


      PubDate: 2015-09-04T15:52:48Z
       
  • Experimental evaluation of the lubrication performance of MoS2/CNT
           nanofluid for minimal quantity lubrication in NI-based alloy grinding
    • Abstract: Publication date: Available online 3 September 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Yanbin Zhang, Changhe Li, Dongzhou Jia, Dongkun Zhang, Xiaowei Zhang
      A nanofluid minimum quantity lubrication with addition of one kind of nanoparticle has several limitations, such as grinding of difficult-to-cutting materials. Hybrid nanoparticles integrate the properties of two or more kinds of nanoparticles, thus having better lubrication and heat transfer performances than single nanoparticle additives. However, the use of hybrid nanoparticles in nanofluid minimum quantity lubrication grinding has not been reported. This study aims to determine whether hybrid nanoparticles have better lubrication performance than pure nanoparticle. A hybrid nanofluid consisting of MoS2 nanoparticles with good lubrication effect and CNTs with high heat conductivity coefficient is investigated. The effects of the hybrid nanofluid on grinding force, coefficient of friction, and workpiece surface quality for Ni-based alloy grinding are analyzed. Results show that the MoS2/CNT hybrid nanoparticles achieve better lubrication effect than single nanoparticles. The optimal MoS2/CNT mixing ratio and nanofluid concentration are 2:1 and 6wt.%, respectively.


      PubDate: 2015-09-04T15:52:48Z
       
  • Recent advances in AFM tip-based nanomechanical machining
    • Abstract: Publication date: Available online 3 September 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Yongda Yan, Yanquan Geng, Zhenjiang Hu
      As one of the tip-based nanomanufacturing (TBN) approaches, the atomic force microscope tip-based nanomechanical technique has already been used to successfully fabricate nanodots, nanolines and two-dimensional or three-dimensional nanostructures on flat or even curved surfaces. This technique exhibits the unique properties of low-cost with simple, highly accurate and flexible control. First, the advances in these areas are reviewed along with the applications of these structures. Second, chemical and thermal energies are also integrated with the mechanical effects, resulting in some new nanomanufacturing methods to extend the scope of the existing TBN methods. The state of the art in this area is then presented. Multi energy resources will become a new growth area for this method. Finally, based on the normal force control strategy of this technique, a summary of the development of several novel micro/nanomachining systems is given. It is hoped that this review will serve to aid in the advance of the existing design and manufacture of micro/nanomechanical machine systems with nanometer accuracy.


      PubDate: 2015-09-04T15:52:48Z
       
  • Investigation on the displacement fluctuation of the linear motor feed
           system considering the linear encoder vibration
    • Abstract: Publication date: Available online 3 September 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Xiaojun Yang, Dun Lu, Jun Zhang, Wanhua Zhao
      Optical linear encoder is generally adopted to realize the full-closed loop control for the linear motor feed system. Its reading head installed on the worktable may vibrate as a result of the excitation of disturbance harmonics, which leads to the encoder’s error. This study aims to investigate the mechanism of displacement fluctuation due to the encoder’s error caused by the worktable vibration in the linear motor feed system. The vibrating modes of feed system are analyzed firstly, and then the influences of three torsional vibrations on encoder’s errors are investigated. The transfer function between disturbance and output response is proposed to analyze the influence of encoder’s error on the displacement fluctuation. The relationships among vibration, encoder’s error, thrust harmonic and displacement fluctuation are discussed in detail. The results show that the encoder’s error can produce obvious displacement fluctuation for the linear motor feed system, which is actually an electromechanical coupling process due to the direct drive and full-closed loop control. Finally, three effective measures are put forward to diminish the system displacement fluctuation.


      PubDate: 2015-09-04T15:52:48Z
       
  • A novel approach for the prediction of the milling stability based on the
           Simpson method
    • Abstract: Publication date: Available online 3 September 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhao Zhang, Hongguang Li, Guang Meng, Chong Liu
      In this paper a new approach is presented for predicting the milling stability based on the Simpson method. Generally the milling dynamic process is described as a linear time-periodic system with a single discrete time delay. By dividing the tooth passing period equally into a finite set of time intervals, the Simpson method is utilized in each time interval to estimate the state items. Then the state transition matrix over one tooth passing period is constructed, and the milling stability could be predicted by the Floquet theory. The convergence rate of the proposed method is discussed, and two benchmark examples are conducted. The results show that the proposed method achieves satisfactory accuracy and efficiency.


      PubDate: 2015-09-04T15:52:48Z
       
  • Generalized Modeling of chip geometry and cutting Forces in multi-point
           thread turning
    • Abstract: Publication date: Available online 28 August 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Mohammad Rezayi Khoshdarregi, Yusuf Altintas
      A generalized mechanics model of multi-point thread turning operations is presented. The cross section of the chip is determined from the thread profiles of the current and previous teeth as well as the infeed settings of the tool. The chip is discretized along the cutting edge, and the cutting force coefficients are evaluated for each element considering the varying effective oblique cutting angles and chip thickness. Nonlinear Kienzle force model is used to account for the effect of edge radius at low chip thickness values. Total cutting forces are obtained by resolving the elemental forces in the insert coordinate system, and integrating them along the engaged teeth. The experimentally validated generalized mechanics model can be used to predict the chip and cutting load distributions for multi-point inserts with custom thread profiles and infeed plans. The model can be used for both process planning and insert design.


      PubDate: 2015-08-30T15:37:58Z
       
  • Generalized method for the analysis of bending, torsional and axial
           receptances of tool-holder-spindle assembly
    • Abstract: Publication date: Available online 29 August 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Yun Yang, Wei-Hong Zhang, Ying-Chao Ma, Min Wan
      Existing researches for the prediction of tool point receptances have focused on developing dedicated methods for cutting tools used in each single cutting operation such as milling and drilling processes. This paper presents a generalized method for the analysis of the tool point receptances of cutting tools suitable for being mounted on a rotating spindle. Translational and rotational dynamic responses related to all axes (X, Y and Z) are simultaneously modeled in a unified way to predict the tool point bending, torsional and axial receptances of all kinds of rotating tools, such as milling, drilling and boring cutters. To facilitate modeling, the tool-holder-spindle assembly is divided into four substructures, i.e., spindle-holder subassembly, shank of tool, fluted part of tool and tool-holder joint interface. The fluted part of tool is modeled as a three-dimensional Timoshenko beam with varying cross-section, while the tool-holder joint interface is regarded as a zero-thickness distributed layer and modeled as a joint substructure composed of a set of independent spring-damper elements. Assembling criterion is derived to couple the dynamic responses of all substructures to calculate the tool point receptances. Meanwhile, compared with past experimental means, a measurement procedure to eliminate the adapter's mass effect on torsional and axial receptances is designed. The proposed method is experimentally proven for two kinds of rotating tools, i.e., mills and drills.


      PubDate: 2015-08-30T15:37:58Z
       
  • Pre-compensation of Servo Contour Errors using a Model Predictive Control
           Framework
    • Abstract: Publication date: Available online 20 August 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Shiyi Yang, Amir H. Ghasemi, Xiangxing Lu, Chinedum E. Okwudire
      Methods for pre-compensating contour errors in servo systems by adding components of the predicted contour error to the reference position command have recently been proposed in the literature. Such methods are very effective when the curvatures of the desired path are small but their performance degrades at locations of sharp curvature because they lack look-ahead capabilities. This paper presents an improved method for pre-compensating contour errors in servo systems by modifying reference position commands using a model predictive control framework. The pre-compensation value at any given location along the desired path is defined as a weighted average of contour errors within a prediction horizon, and the weights are selected to minimize the sum of squares of the estimated contour errors over the chosen prediction horizon. Constraint enforcement functionalities are also built into the proposed method to ensure that the pre-compensated reference commands stay within specified velocity and acceleration limits. Simulations and experiments are used to compare the performance of the proposed method to a recently-proposed pre-compensation approach which lacks look-ahead and constraint enforcement capabilities. Significant improvements in contouring accuracy over the existing method are demonstrated.


      PubDate: 2015-08-21T15:05:48Z
       
  • Single setup identification of component errors for rotary axes on
           five-axis machine tools based on pre-layout of target points and shift of
           measuring reference
    • Abstract: Publication date: Available online 14 August 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhouxiang Jiang, Bao Song, Xiangdong Zhou, Xiaoqi Tang, Shiqi Zheng
      This paper proposes a single setup identification method of 12 component errors of rotary axes on five-axis machine tools by using a touch trigger probe and an artefact. At first, a basic idea of pre-layout of target points combined with the shift of measuring reference is proposed. Influence of setup errors of touch trigger probe and artefact on measuring results is identified quantitatively and included in error models. A single setup measuring method is then designed to identify 12 component errors of rotary axes on five-axis machine tools with a tilting head and a rotary table. The expansion of this basic idea on five-axis machine tools with other configurations is also provided. Validation and uncertainty analysis of the identified values are also provided. The measuring accuracy is guaranteed by the complete error model while the measuring efficiency is improved significantly by the single setup measuring method.


      PubDate: 2015-08-18T14:51:48Z
       
  • A two-layered cross coupling control scheme for A three-dimensional motion
           control system
    • Abstract: Publication date: Available online 12 August 2015
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Dainlin Zhang, Jixiang Yang, Yuanhao Chen, Youping Chen
      A two-layered modeling and compensation scheme is proposed to reduce the contouring error of a three-dimensional motion control system. In the proposed scheme, the contouring error model of the three-dimensional motion control system is divided into two layers: the top layer and the bottom layer. The proposed multi-layered structure of the contouring error model presents more flexibility in the control system design because the cross coupling controllers in different layers can be designed separately. In this paper, a nonlinear PI controller and a position error compensator are designed in the bottom layer in order to achieve high contouring accuracy in the XY plane, while a unilateral compensator is designed in the top layer to further reduce contouring error in the three dimensional space. Finally, experiments are performed to verify the performance of the proposed two-layered modeling and compensation scheme. Experiment results show that the designed two-layered cross coupling controller can obtain higher contouring accuracy than traditional cross coupling controller both in the XY plane and in the XYZ space.


      PubDate: 2015-08-14T14:19:36Z
       
 
 
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