for Journals by Title or ISSN
for Articles by Keywords
help
  Subjects -> MANUFACTURING AND TECHNOLOGY (Total: 253 journals)
    - CERAMICS, GLASS AND POTTERY (24 journals)
    - MACHINERY (32 journals)
    - MANUFACTURING AND TECHNOLOGY (151 journals)
    - METROLOGY AND STANDARDIZATION (3 journals)
    - PACKAGING (13 journals)
    - PAINTS AND PROTECTIVE COATINGS (5 journals)
    - PLASTICS (25 journals)

MACHINERY (32 journals)

Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9)
Advanced Energy Materials     Hybrid Journal   (Followers: 13)
Applied Mechanics Reviews     Full-text available via subscription   (Followers: 23)
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: 3)
Electric Power Components and Systems     Hybrid Journal   (Followers: 5)
Engenharia AgrĂ­cola     Open Access  
Foundations and Trends® in Electronic Design Automation     Full-text available via subscription  
High Temperature Materials and Processes     Full-text available via subscription   (Followers: 4)
International Journal of Machine Tools and Manufacture     Hybrid Journal   (Followers: 4)
International Journal of Machining and Machinability of Materials     Hybrid Journal   (Followers: 5)
International Journal of Manufacturing Technology and Management     Hybrid Journal   (Followers: 8)
International Journal of Precision Technology     Hybrid Journal  
International Journal of Rapid Manufacturing     Hybrid Journal   (Followers: 2)
International Journal of Rotating Machinery     Open Access   (Followers: 1)
ISRN Mechanical Engineering     Open Access   (Followers: 5)
Journal of Machinery Manufacture and Reliability     Hybrid Journal  
Journal of Machinery Manufacturing and Automation     Open Access   (Followers: 1)
Journal of Mechanics     Hybrid Journal   (Followers: 16)
Journal of Strain Analysis for Engineering Design     Hybrid Journal   (Followers: 4)
Journal of Terramechanics     Hybrid Journal   (Followers: 1)
Machine Design     Partially Free   (Followers: 8)
Machines     Open Access  
Materials     Open Access   (Followers: 5)
Mechanics Based Design of Structures and Machines: An International Journal     Hybrid Journal   (Followers: 2)
Micromachines     Open Access   (Followers: 1)
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: 4)
Journal Cover International Journal of Machine Tools and Manufacture
   Journal TOC RSS feeds Export to Zotero [6 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0890-6955
     Published by Elsevier Homepage  [2563 journals]   [SJR: 2.724]   [H-I: 71]
  • A generalized on-line estimation and control of five-axis contouring
           Errors of CNC machine Tools
    • Abstract: Publication date: Available online 24 August 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jixiang Yang , Yusuf Altintas
      Nonlinear and configuration-dependent five-axis kinematics make contouring errors difficult to estimate and control in real time. This paper proposes a generalized method for the on-line estimation and control of five-axis contouring errors. First, a generalized Jacobian function is derived based on screw theory in order to synchronize the motions of linear and rotary drives. The contouring error components contributed by all active drives are estimated through interpolated position commands and the generalized Jacobian function. The estimated axis components of contouring errors are fed back to the position commands of each closed loop servo drive with a proportional gain. The proposed contouring error estimation and control methods are general, and applicable to arbitrary five-axis tool paths and any kinematically admissible five-axis machine tools. The proposed algorithms are verified experimentally on a five-axis machine controlled by a modular research CNC system built in-house. The contouring errors are shown to be reduced by half with the proposed method, which is simple to implement in existing CNC systems.


      PubDate: 2014-09-04T22:46:10Z
       
  • Improving CNC contouring accuracy by robust digital integral sliding mode
           control
    • Abstract: Publication date: Available online 4 September 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Xue-Cheng Xi , Wan-Sheng Zhao , Aun-Neow Poo
      Integral sliding mode control (ISMC) has been employed and shown to improve contouring accuracy in the presence of external disturbances and model uncertainties. An ISMC controller directly reduces the tracking error of each individual axis, thereby reducing the overall contour errors indirectly. An ISMC controller drives the system dynamics back onto the sliding surface if there exists a deviation from the predefined surface. In the design of an ISMC controller, it is crucial to choose an appropriate sliding surface as this has a great impact on system performance and on chattering. In current approaches, the sliding mode surface is chosen largely based on a rule of thumb which is only applicable for systems with open-loop poles having imaginary parts. In this paper, an approach is presented to design the sliding surface using principles of robust digital control so that both the regulation and robustness requirements can be satisfied. The natural frequency of the dominant closed-loop poles are chosen such that the modulus of the output sensitivity function lies within robustness bounds. Resonant pole-zero filters are then used to reshape the output sensitivity function in specific frequency regions. Experiments showed that when the output sensitivity function is kept within the robustness bounds, chattering can be avoided and the contour errors resulting from vibrations can be reduced. The introduction of a pole-zero filter also allowed the attenuation band to be expanded so that the low frequency components of the contour errors are attenuated.


      PubDate: 2014-09-04T22:46:10Z
       
  • Depth-of-cut errors in ELID surface grinding of zirconia-based ceramics
    • Abstract: Publication date: Available online 30 August 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): H. Tang , Z.H. Deng , Y.S. Guo , J. Qian , D. Reynaerts
      Based on the analysis of a surface grinding system and the material removal mechanism, a mathematic model has been proposed to predict the accumulated error between the total set depth-of-cut (DoC) and the total actual depth-of-cut (ADoC) in multi-pass surface grinding of zirconia-based ceramic materials. Design of Experiments (DoE) approach has been implemented to carry out experiments. The influence of the set DoC of each grinding pass, the total set DoC, and the grinding wheel velocity on the accumulated errors in ADoC has been investigated in details in surface grinding of zirconia-based ceramics both with electrolysis in-process dressing (ELID) and without ELID. It has been observed that the accumulated DoC errors increase faster in the first a few passes and gradually reach a saturation after a certain total DoCs (about 8–10 grinding passes) and a higher step DoC leads to a faster (fewer passes) saturation of the accumulated DoC errors. Compared to grinding without ELID, it has been found that ELID-grinding is characterized with better process stability and ELID offers positive effects on material removal rate (MRR), especially in case of removing large volume of material with the same grinding parameters.


      PubDate: 2014-09-04T22:46:10Z
       
  • IFC - Editorial board
    • Abstract: Publication date: November 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 86




      PubDate: 2014-08-18T21:40:31Z
       
  • Validation of volumetric error compensation for a five-axis machine using
           surface mismatch producing tests and on-machine touch probing
    • Abstract: Publication date: Available online 12 August 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Mehrdad Givi , J.R.R. Mayer
      In order to validate volumetric error compensation methods for five-axis machine tools, the machining of test parts have been proposed. For such tests, a coordinate measuring machine (CMM) or other external measurement, outside of the machine tool, are required to measure the accuracy of the machined part. In this paper, a series of machining tests are proposed to validate a compensation strategy and compare the machining accuracy before and after the compensation using only on-machine measurements. The basis of the tests is to machine slots, each completed using two different rotary axes indexations of the CNC machine tool. Using directional derivatives of the volumetric errors, it is possible to verify that a surface mismatch is produced between the two halves of the same slot in the presence of specific machine geometric errors. The mismatch at the both sides of the slot, which materialize the machine volumetric errors are measured using touch probing by the erroneous machine itself and with high accuracy since the measurement of both slot halves can be conducted using a single set of rotary axes indexation and in a volumetric region of a few millimetres. The effect of a compensation strategy is then validated by comparing the surface mismatch value for compensated and uncompensated slots.


      PubDate: 2014-08-14T21:30:41Z
       
  • A method of using turning process excitation to determine dynamic cutting
           coefficients
    • Abstract: Publication date: Available online 12 August 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Kuanmin Mao , Ming Zhu , Weiwei Xiao , Bin Li
      Identification of the dynamic cutting force coefficients is essential in cutting process modeling. The excitation equipment employed to produce dynamic cutting process are usually sophisticated and may lead to potential error. An alternative method of turning process excitation is proposed to simplify the procedure of cutting dynamics measurement. A cantilever workpiece used in cylindrical turning process has been modeled with a double degree-of-freedom system that supports variable dynamic parameters. The structural dynamics of the equivalent system are analyzed with the theoretical derivation and the finite element simulations. The influence of structural dynamic variation on the chatter frequency is investigated, based on which the self-excited chatter is considered as a method of the turning process excitation. This method is applied in the cutting dynamics tests. The dynamic cutting force coefficients could be measured through a single chattering turning process. Stability analysis is conducted for verification of the measured dynamic cutting coefficients.


      PubDate: 2014-08-14T21:30:41Z
       
  • A new error measurement method to identify all six error parameters of A
           rotational axis of A machine tool
    • Abstract: Publication date: Available online 11 August 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhenya He , Jianzhong Fu , Liangchi Zhang , Xinhua Yao
      This paper presents a new error measurement method, a Dual Optical Path Measurement Method (DOPMM), to identify error parameters of the rotational axis of a machine tool along its error sensitive directions. The method development was carried out on a motorized rotary stage equipped with a Doppler laser instrument. An error measurement experiment and a machining experiment were conducted on a five-axis machining center with a titling rotary table. It was found that the DOPMM can identify all of the six volumetric error parameters with the simple algebraic operations. Compared with the existing ball bar tests, which need a mathematical error modeling of machine tools to separate the error parameters, the identified process of DOPMM is more simple and easier to understand. And the operation of machine tools during the measurement is much easier than that of the existing ball bar tests. The experimental results showed that the part precision can have a significant improvement of 68% when the identified error parameters are used for error compensation. Hence, the measurement method established in this study is sensible and efficient, and could be used for the error compensation on a wide range of machine tools to improve their machining precision.


      PubDate: 2014-08-11T21:20:44Z
       
  • Feed speed scheduling method for parts with rapidly varied geometric
           feature based on drive constraint of NC machine tool
    • Abstract: Publication date: Available online 11 August 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zhenyuan Jia , Ling Wang , Jianwei Ma , Kai Zhao , Wei Liu
      Parts with rapidly varied geometric feature are widely applied in the fields of aerospace, energy power, and automobile, and are difficult to process because of the more special structure and the higher requirement of machining precision. As the existence of rapidly varied geometric feature and during the NC manufacturing process of this kind of parts, the actual moving speed of the workbench of the NC machine tool cannot reach the feed speed set in the NC program timely due to the drive constraint of NC machine tool. Furthermore, the machine tool would vibrate violently with the drive constraint when employing the constant machining parameter to process the parts with rapidly varied geometric feature, which seriously restricts the improvement of processing this kind of parts with high quality and high efficiency. In order to manufacture such parts with high quality and high efficiency, a sub-regional processing method with variable machining parameters is proposed. Firstly, the generation mechanism of the machining error is studied, and its mathematical model is built. Then the change rule of the machining error influenced by the curvature and the NC programmed feed speed is found out. Finally, taking the drive constraint and the machining error requirement into account, the relationship between the programmed feed speed and the curvature is established, and the corresponding programmed feed speeds to different curvatures are obtained. Taking the NC machining of the edge line of spiral microstrip antenna, which is an equiangular spiral, for example, the experiment results show that compared with the machining result with constant machining parameter, the maximum machining error of the sub-regional processing method with variable machining parameters decreases by 35.51% and the average value of the machining error decreases by 46.65%. For another example, the clover rose line is machined and the processing quality is also improved. This study proves that the method distributing the programmed feed speeds based on the curvature variation can improve the machining precision and ensure processing efficiency, and provides an effective method to manufacture parts with rapidly varied geometric feature.


      PubDate: 2014-08-11T21:20:44Z
       
  • Experimental and numerical studies of the solution heat treatment,
           forming, and in-die quenching (HFQ) process on AA5754
    • Abstract: Publication date: Available online 1 August 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Omer El Fakir , Liliang Wang , Daniel Balint , John P. Dear , Jianguo Lin , Trevor A. Dean
      An FE model of the solution Heat treatment, Forming and in-die Quenching (HFQ) process was developed. Good correlation with a deviation of less than 5% was achieved between the thickness distribution of the simulated and experimentally formed parts, verifying the model. Subsequently, the model was able to provide a more detailed understanding of the HFQ process, and was used to study the effects of forming temperature and speed on the thickness distribution of the HFQ formed part. It was found that a higher forming speed is beneficial for HFQ forming, as it led to less thinning and improved thickness homogeneity.


      PubDate: 2014-08-05T21:02:35Z
       
  • Mechanics and dynamics of thread milling process
    • Abstract: Publication date: Available online 29 July 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Min Wan , Yusuf Altintas
      This paper presents the mechanics and dynamics of thread milling operations. The tool follows a helical path around the wall of the pre-machined hole in thread milling, which has varying tool-part engagement and cut area during one threading cycle. The variation of cut area that reflects the kinematics of threading as well as structural vibrations is modeled along the helical, threading path. The mechanics of the process are first experimentally proven, followed by the formulation of dynamic thread milling which is periodic in threading cycle, in a semi-discrete time domain. The stability of the operation is predicted as a function of spindle speed, axial depth of cut, cutter path and tool geometry. The mechanics and stability models are experimentally proven in opening M16×2 threads with a five-fluted helical tool on a Steel AISI1045 workpiece.


      PubDate: 2014-08-01T20:44:30Z
       
  • Dynamics of Ultra-High-Speed (UHS) Spindles used for Micromachining
    • Abstract: Publication date: Available online 30 July 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Bekir Bediz , B. Arda Gozen , Emrullah Korkmaz , O. Burak Ozdoganlar
      Micromachining dynamics commonly dictate the attainable accuracy and throughput that can be obtained from micromachining operations. The dynamic behavior of miniature ultra-high-speed (UHS) spindles used in micromachining critically affects micromachining dynamics. As such, there is a strong need for effective techniques to characterize the dynamic behavior of miniature UHS spindles. This paper presents a systematic experimental approach to obtain the speed-dependent two-dimensional dynamics of miniature UHS spindles through experimental modal analysis. A miniature cylindrical artifact with 5mm overhang is attached to (and rotating with) the spindle to enable providing the dynamic excitations to and measuring the resulting motions of the spindle. A custom-made impact excitation system is used to reproducibly excite the spindle dynamics up to 20kHz while controlling the impact force. The resulting radial motions of the spindle are measured in two mutually-perpendicular directions using two independent fiber-optic laser Doppler vibrometers (LDVs). To ensure the mutual orthogonality of the measurements, the two lasers are aligned precisely using an optical procedure. A frequency-domain filtering approach is used to remove the unwanted spindle motion data from the measurements, thereby isolating the dynamic response. The spindle dynamics is then represented in the form of frequency response functions (FRFs). A global curve-fitting technique is applied to identify natural frequencies and damping ratios. The developed approach is demonstrated on a miniature UHS spindle with aerodynamic bearings, and dynamic characteristics are analyzed at different spindle speeds and collet pressures. The spindle speed is shown to have a significant effect on dynamic response, especially at higher spindle speeds, while the collet pressure is observed not to have any significant effect on the spindle dynamics. It is concluded that the presented approach can be used to characterize the dynamics of miniature UHS spindles effectively.


      PubDate: 2014-08-01T20:44:30Z
       
  • A review of modeling and simulation of laser beam machining
    • Abstract: Publication date: October 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 85
      Author(s): Pedram Parandoush , Altab Hossain
      Laser beam machining (LBM) is a widely used thermal advance machining process capable of high accuracy machining of almost any material with complex geometries. CO2 and Nd:YAG lasers are mostly used for industrial purposes. Drilling, cutting, grooving, turning and milling are the applications of LBM with different material removal mechanisms. Modeling and simulation of the LBM process is indispensable for optimization purposes. Modeling can be done by implementing analytical, numerical, experimental and artificial intelligence-based methods. This paper provides a review of the various methods used for modeling and simulation of the laser beam machining process as well as key researches done in this field so far.


      PubDate: 2014-07-27T20:26:40Z
       
  • Development and implementation of a NURBS interpolator with smooth
           feedrate scheduling for CNC machine tools
    • Abstract: Publication date: Available online 22 July 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Min Liu , Yu Huang , Ling Yin , JianWen Guo , XinYu Shao , GuoJun Zhang
      Parametric interpolation for Non-Uniform Rational B-Spline (NURBS) curve has become more important than ever before in the control of CNC machine tools. An effective NURBS interpolator not only can obtain accurate contour trajectories, but also have smooth dynamics performance. This paper proposes a numerically efficient NURBS interpolation scheme which consists of two stages namely preprocessing and interpolating. In the stage of pre-processing, the parameter interval is split into several blocks at breakpoints and an iterative numerical quadrature method is applied for each block. By means of the iterative quadrature method, the initial parameter intervals of each block are divided into several subintervals according to the arc length approximation error. Meanwhile, the curvature of each knot and the cubic polynomial coefficients of each subinterval are obtained. Then the critical points with large curvature of each block are found from the candidate points and the tolerated speed of each critical point is calculated according to the constraints of chord error and centripetal acceleration. Hence, the feedrate scheduling based on the S-shaped acceleration profile for each block can be preplanned via the approximate arc length of each subinterval, the tolerated speed of each critical point and kinematics characteristics such as acceleration/deceleration and jerk limits of the machine tools. In the stage of interpolating, the parameter of the next interpolation point can be calculated directly using the cumulative arc length and the cubic polynomial coefficients of each subinterval. Finally, a series of numerical simulations and real machining experiments are conducted , and the simulation and experimental results have showed the good performance of the proposed NURBS interpolator both in efficiency and accuracy.
      Graphical abstract image Highlights

      PubDate: 2014-07-27T20:26:40Z
       
  • A real-time look-ahead interpolation algorithm based on Akima curve
           fitting
    • Abstract: Publication date: October 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 85
      Author(s): Yunsen Wang , Dongsheng Yang , Yinzhong Liu
      To process the complex geometric-shapes consisting of discrete data points, this paper presents a real-time look-ahead interpolation algorithm based on Akima curve fitting. The algorithm consists of two modules: pretreatment module and real-time interpolation module. The pretreatment module firstly adopts the bi-chord and tangent-chord criteria to identify those continuous Akima blocks and calculates the linking velocity between two adjacent blocks according to the required machining accuracy. Then the five-point Akima method is used to fit the continuous blocks into a Akima spline curve. In the real-time interpolation module, the look-ahead interpolation is executed to ensure that the processing error is limited in a satisfying range, and the Newton iteration method is employed to calculate the parameters when interpolating Akima spline blocks. Simulations and experimental results demonstrate that the Akima spline is more suitable when processing discrete data points. And the proposed look-ahead interpolation algorithm could reduce the feedrate fluctuation to satisfactory level and implement high-quality CNC processing.


      PubDate: 2014-07-27T20:26:40Z
       
  • Fabrication of hollow nickel micro-spheres with high degree of hollowness
           by silicon powder-mixed spark erosion
    • Abstract: Publication date: October 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 85
      Author(s): Huabei Peng , Deping Yu , Xun Zhang , Shanling Wang , Yuhua Wen
      For the purpose of developing a simple, fast and low cost method to fabricate the hollow nickel micro-spheres, the hollow nickel micro-spheres with high degree of hollowness were fabricated by silicon powder-mixed spark erosion (SPMSE) in the present paper. Morphologies and loose packed densities of hollow nickel micro-spheres fabricated by the SPMSE and conventional spark erosion (CSE) respectively were studied. The results showed that the hollow nickel micro-spheres fabricated by the SPMSE are bigger and exhibit higher degree of hollowness as compared to the CSE. It is expected that the powder-mixed spark erosion can fabricate hollow nickel micro-spheres with satisfactory particle size and hollowness through adjusting the particle size of silicon powders and machining parameters, even selecting other kinds of semi-conductive or conductive powders. In addition, the powder-mixed spark erosion can also fabricate other kinds of hollow metallic micro-spheres.
      Graphical abstract image

      PubDate: 2014-07-27T20:26:40Z
       
  • An approach for measuring the FRF of machine tool structure without
           knowing any input force
    • Abstract: Publication date: November 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 86
      Author(s): Xinyong Mao , Bo Luo , Bin Li , Hui Cai , Hongqi Liu , Fangyu Pen
      Measuring the dynamics of a machine tool is important for improving its processing or design. In general, the dynamics of the machine tool structure is identified by the experimental modal analysis approaches that require the measurement of both the input loadings and the corresponding structural responses. However, the primary limitation for this method is that the input loadings are difficult or impossible to be measured when the machine tool is under operational conditions. In this paper, a method that is based on random decrement technology was used to identify the operational modal parameters of a machine tool without the knowledge of any of the inputs. To estimate the frequency response functions, FRFs, a structural change method was proposed. The approach is based on the sensitivity of the eigenproperties to structural modifications caused by the drive positions. The proposed method was verified experimentally by traditional hammer tests. Because no elaborate excitation equipment is used, the dynamics of the machine tool structure with arbitrarily feed rate or working position can be easily identified using the proposed active excitation modal analysis method.


      PubDate: 2014-07-27T20:26:40Z
       
  • A machining test to calibrate rotary axis error motions of five-axis
           machine tools and its application to thermal deformation test
    • Abstract: Publication date: November 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 86
      Author(s): Soichi Ibaraki , Yusuke Ota
      This paper proposes a machining test to parameterize error motions, or position-dependent geometric errors, of rotary axes in a five-axis machine tool. At the given set of angular positions of rotary axes, a square-shaped step is machined by a straight end mill. By measuring geometric errors of the finished test piece, the position and the orientation of rotary axis average lines (location errors), as well as position-dependent geometric errors of rotary axes, can be numerically identified based on the machine׳s kinematic model. Furthermore, by consequently performing the proposed machining test, one can quantitatively observe how error motions of rotary axes change due to thermal deformation induced mainly by spindle rotation. Experimental demonstration is presented.


      PubDate: 2014-07-27T20:26:40Z
       
  • IFC - Editorial board
    • Abstract: Publication date: October 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 85




      PubDate: 2014-07-27T20:26:40Z
       
  • Developments in the non-traditional machining of particle reinforced metal
           matrix composites
    • Abstract: Publication date: November 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 86
      Author(s): A. Pramanik
      The non-traditional machining of particulate reinforced metal matrix composites is relatively new. However, researchers seem to pay more attention in this field recently as the traditional machining of particulate reinforced metal matrix composites is very complex. This research investigates different non-traditional machining, such as electro-discharge, laser beam, abrasive water jet, electro-chemical and electro-chemical discharge machining of this composite materials. The machining mechanism, material removal rate/machining speed and surface finish have been analysed for every machining process. This analysis clearly shows that vaporisation, melting, chemical dissolution and mechanical erosion are the main material removal mechanisms during non-traditional machining. The thermal degradation and the presence of reinforcement particles mainly damage the machined surface. The understanding of electro-discharge, laser beam and abrasive water jet machining is more developed than that of electro-chemical and electro-chemical discharge machining for particulate reinforced MMC.


      PubDate: 2014-07-27T20:26:40Z
       
  • Critical cutting speed for onset of serrated chip flow in high speed
           machining
    • Abstract: Publication date: November 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 86
      Author(s): G.G. Ye , Y. Chen , S.F. Xue , L.H. Dai
      The transition of continuously smooth chip flow to periodically serrated chip flow as the cutting speed increasing is one of the most fundamental and challenging problems in high speed machining. Here, an explicit expression of the critical cutting speed for the onset of serrated chip flow, which is given in terms of material properties, uncut chip thickness and tool rake angle, is achieved based on dimensional analysis and numerical simulations. It could give reasonable predictions of the critical cutting speeds at which chips change from continuous to serrated for various metallic materials over wide ranges of uncut chip thickness and tool rake angle. More interestingly, it is found that, as the turbulent flow is controlled by the Reynolds number, the transition of the serrated chip flow mode is dominated by a Reynolds thermal number. Furthermore, the influences of material properties on the emergence of serrated chip flow are systematically investigated, the trends of which show good agreement with Recht’s classical model.


      PubDate: 2014-07-27T20:26:40Z
       
  • Investigation of the effects of cryogenic treatment applied at different
           holding times to cemented carbide inserts on tool wear
    • Abstract: Publication date: November 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 86
      Author(s): Nursel Altan Özbek , Adem Çiçek , Mahmut Gülesin , Onur Özbek
      Cutting tool costs is one of the most important components of machining costs. For this reason, tool life should be improved using some methods such as cutting fluid, optimal cutting parameters, hard coatings and heat treatment. Recently, another one of the methods commonly used to improve tool life is cryogenic treatment. This study was designed to evaluate the effects of different holding times of deep cryogenic treatment on tool wear in turning of AISI 316 austenitic stainless steel. The cemented carbide inserts were cryogenically treated at −145°C for 12, 24, 36, 48 and 60h. Wear tests were conducted at four cutting speeds (100, 120, 140 and 160m/min), a feed rate of 0.3mm/rev and a 2.4mm depth of cut under dry cutting conditions. The wear test results showed that flank wear and crater wear were present in all combinations of the cutting parameters. However, notch wear appeared only at lower cutting speeds (100 and 120m/min). In general, the best wear resistance was obtained with cutting inserts cryogenically treated for 24h. This case was attributed to the increased hardness and improved micro-structure of cemented carbide inserts. These improvements were confirmed through hardness, image processing, and XRD analyses.


      PubDate: 2014-07-27T20:26:40Z
       
  • A systematic optimization approach for the calibration of parallel
           kinematics machine tools by a laser tracker
    • Abstract: Publication date: November 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 86
      Author(s): Jia-Feng Wu , Rui Zhang , Rui-He Wang , Ying-Xue Yao
      Parallel kinematics machine has attracted attention as machine tools because of the outstanding features of high dynamics and high stiffness. Although various calibration methods for parallel kinematics machine have been studied, the influence of inaccurate motion of joints is rarely considered in these studies. This paper presents a high-accuracy and high-effective approach for calibration of parallel kinematics machine. In the approach, a differential error model, an optimized model and a statistical method are combined, and the errors of parallel kinematics machine due to inaccurate motion of joints can be reduced by this approach. Specifically, the workspace is symmetrically divided into four subspaces, and a measurement method is suggested by a laser tracker to require the actual pose of the platform in these subspaces. An optimized model is proposed to solve the kinematic parameters in symmetrical subspaces, and then arithmetical mean method is proposed to calculate the final kinematic parameter. In order to achieve the global optimum quickly and precisely, the initial value of the optimal parameter is directly solved based on the differential error model. The proposed approach has been realized on the developed 5-DOF hexapod machine tool, and the experiment result proves that the presented method is very effective and accurate for the calibration of the hexapod machine tool.
      Graphical abstract image

      PubDate: 2014-07-27T20:26:40Z
       
  • Fabrication of hybrid micro/nano-textured surfaces using rotary ultrasonic
           machining with one-point diamond tool
    • Abstract: Publication date: November 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 86
      Author(s): Shaolin Xu , Keita Shimada , Masayoshi Mizutani , Tsunemoto Kuriyagawa
      A novel rotary ultrasonic texturing (RUT) technique is proposed to fabricate hybrid periodic micro/nano-textures on flat surfaces. Different from conventional rotary ultrasonic machining, a tailored one-point diamond tool was manufactured and employed for RUT on surfaces of electroless nickel–phosphorus (Ni–P) plating. A one-dimensional longitudinal-vibration mode is used. The combined effect of ultrasonic vibration, rotation and feed motion leads to high-frequency periodic change of cutting edge׳s motion, which is the basic principle for the RUT process. Therefore, to accurately predict and control the texturing process, the cutting locus is firstly mathematically calculated. Hybrid periodic micro/nano-textures comprising linear grooves at the micrometer scale and sinusoidal grooves at the micrometer or nanometer scale were successfully fabricated on machined surfaces, which are in compliance with the results of the mathematical calculations. Different types of surface textures were generated by changing machining conditions. The surface generation mechanism of RUT is illustrated and discussed by analyzing the surface textural features, the cutting locus and the tool tip׳s geometry, including various tool faces, cutting edges, and the cutting corner. The requirements for RUT technique are concluded.


      PubDate: 2014-07-27T20:26:40Z
       
  • Experimental investigation of drilling damage and stitching effects on the
           mechanical behavior of carbon/epoxy composites
    • Abstract: Publication date: Available online 17 July 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Yosra Turki , Malek Habak , Raphaël Velasco , Zoheir Aboura , Kamel Khellil , Pascal Vantomme
      The main purpose of composite materials drilling is the need to put together different parts of a structure, in aeronautics for example. Machining generates damages which affect mechanical properties and have to be taken into account during manufacturing process. The objective of this study is to experimentally analyze the influence of drilling on a carbon/epoxy composite, to investigate the relationships among damages, cutting forces, mechanical properties of the drilled specimens and crack propagation. Stitching and a range of spindle speed and feed have been tested when drilling with a classic twist drill. The effect of each parameter has been assessed in terms of thrust force, moment (during machining) and defects, and then linked to mechanical test results. Experimental results have shown significant influences of feed and composite configuration on delamination. Furthermore, cyclic tensile tests have shown that reducing damage and using stitching help increasing tensile strength.


      PubDate: 2014-07-27T20:26:40Z
       
  • Investigation of a new incremental counter forming in flexible roll
           forming to manufacture accurate profiles with variable cross-sections
    • Abstract: Publication date: Available online 14 July 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jong-Cheol Park , Dong-Yol Yang , MyongHwan Cha , DonGun Kim , Jae-Bok Nam
      A roll-formed profile with variable cross-sections fabricated by flexible roll forming has a shape error, such as warping, because of geometrical deviations in transitional zones of the profile between the initial metal strip and the roll-formed profile. To reduce the shape error, a new process called incremental counter forming (ICF) is proposed. Our investigation of the ICF process shows that the longitudinal strain distribution at the flange of the roll-formed profile can be controlled by combinations of forming parameters of the ICF process. As the forming parameters increase the longitudinal strain distribution in the concave zone, the shape error decreases. However, when the longitudinal strain distribution in the straight zone reaches a critical limit, the additional longitudinal strain works as an excessive longitudinal strain to worsen the shape error. An analytical model, which describes the longitudinal strain at the flange during roll forming, is adopted to reveal that the increase of the longitudinal strain is induced by increasing derivatives of a bending angle, which is controlled by the forming parameters of the ICF process. Finally, the FE simulation has been carried out to compare with the experimental results, which show that the ICF process is effective for reducing the shape error of the profile with variable cross-sections in flexible roll forming.


      PubDate: 2014-07-27T20:26:40Z
       
  • An investigation of workpiece temperature variation of helical milling for
           carbon fiber reinforced plastics (CFRP)
    • Abstract: Publication date: Available online 10 July 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jie Liu , Guang Chen , Chunhui Ji , Xuda Qin , Hao Li , Chengzu Ren
      Better prediction about the temperature distribution of workpiece has a great significance for improving performance of cutting process, especially relating to the workpiece of carbon fiber reinforced plastics (CFRP). In this paper, a heat transfer model is developed to investigate the temperature distribution of CFRP workpiece in helical milling process. Depending on characteristics of helical milling, two kinds of heat sources have been presented, the geometrical shapes of which are modeled as semicircle arc and line. The complex trajectory of each heat source relative to the stable workpiece has been studied. Based on the analysis, unsteady state three-dimensional governing equation of heat transfer in CFRP workpiece with adiabatic boundary condition is proposed. The solution procedure of this nonhomogeneous heat transfer equation consists of two steps: it is transformed into homogeneous equation according to the heat transfer theory firstly; and then the homogeneous equation is solved using the separation of variables. Basing on the solution of the homogeneous equation, the temperature distribution resulting from the moving semicircle arc heat source and the line heat source has been studied detailedly. In order to calculate the heat generation in the helical milling process, a cutting force model is presented and the heat partition transferring into the CFRP workpiece is solved using the Conjugate Gradient Method. A series of tests of helical milling for CFRP are conducted, and the experiment results agree well with the results calculated by the predicted model. This model can be extended to optimize the cutting condition and restrain the thermal damage of the CFRP workpiece.


      PubDate: 2014-07-27T20:26:40Z
       
  • Novel ancillary device for minimising machining vibrations in thin wall
           assemblies
    • Abstract: Publication date: Available online 5 June 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): K. Kolluru , D. Axinte
      Milling thin wall structures is challenging due to their low stiffness and hence consequential vibration problems. Most of the research in this area was focussed on minimising chatter vibrations – either through generation of stability lobes or by employing targeted damping solutions such as piezoelectric damping; such solutions are suitable only for damping resonant vibrations. However, most of the thin wall structures also get poor surface finish due to forced vibrations either at tooth cutting frequency or tool natural frequencies. In this work, relying on the importance of improving mass and stiffness for greater vibration reduction in milling circular thin-wall components, an innovative articulated device pre-tensioned by torsion springs is proposed. The concept is novel in the sense that it is compact and light-weight and can be used on any shape of thin wall structure. Employing such a device does not alter the nature of dynamic characteristic of the structure thus ensuring better control of achieved dimension of structure. Significant (8 times) vibration reduction was observed using proposed device.


      PubDate: 2014-06-14T15:51:09Z
       
  • A Review of Process Advancement of Novel Metal Spinning
    • Abstract: Publication date: Available online 23 May 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Qinxiang Xia , Gangfeng Xiao , Hui Long , Xiuquan Cheng , Xiangfei Sheng
      Metal spinning technology has seen a rapid development in recent years. Novel spinning processes, such as non-axisymmetric spinning, non-circular cross-section spinning and tooth-shaped spinning, are being developed. This has challenged the limitation of traditional spinning technology being used for manufacturing axisymmetric, circular cross-section, and uniform wall-thickness parts. In this paper, the classification of the traditional spinning processes is proposed based on the material deformation characteristics, the relative position between roller and blank, mandrel spinning and mandrel-free spinning, and temperature of the blank during spinning. The advancement of recently developed novel spinning processes and corresponding tool design and equipment development are reviewed. The classification of the novel spinning processes is proposed based on the relative position between the rotating axes, the geometry of cross-section and the variation of wall-thickness of spun parts. The material deformation mechanism, processing failures and spun part defects of the aforementioned three groups of novel spinning processes are discussed by analyzing four representative spinning processes of industrial applications. Furthermore other novel spinning processes and their classification as reported in the literature are summarized.


      PubDate: 2014-06-14T15:51:09Z
       
  • Thermal modelling and characteristics analysis of High speed press system
    • Abstract: Publication date: Available online 11 June 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Enlai Zheng , Fang Jia , Sihong Zhu
      The traditional thermal model of presses neglects the effect of roughness between two contact surfaces on the contact conduction coefficient, which causes the analysis to have a low accuracy. The primary objective of this work is to propose an improved thermal model of the high speed press system with the thermal contact resistance between solid joints and the change of the heat generation power with the temperature of bearings considered to analyze its thermal characteristics. Based on the fractal model and the change of the heat generation power, a complete thermal model for the high speed press system is developed. The temperature histories and the time for reaching thermal equilibrium condition of the high speed press system are explored by the finite element (FE) method. The experimental results demonstrate that the complete model is more accurate than the model without considering the thermal contact resistance and the change of the heat generation power. The thermal expansion of the high speed press system is also investigated, which can provide a theoretical basis for design of structure and intelligent lubrication system to improve its precision.
      Graphical abstract image

      PubDate: 2014-06-14T15:51:09Z
       
  • Characterization of friction behaviour of AZ80 and ZE10 magnesium alloys
           under lubricated contact condition by strip draw and bend test
    • Abstract: Publication date: October 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 85
      Author(s): Maziar Ramezani , Thomas Neitzert , Timotius Pasang , M.A. Sellès
      In this paper, a sheet metal forming simulator (SMFS) is used for evaluation of the frictional behaviour of AZ80 and ZE10 magnesium alloys under lubricated contact conditions. The results showed that the friction coefficient increases by increasing the contact pressure and decreasing the sliding velocity. A friction model is further developed for lubricated contact taking into account the surface roughness characteristics and the viscosity of lubricant. The proposed model showed very good agreement with the results of experiments. Finite element (FE) simulations were also carried out to investigate the effect of key process parameters on the results of SMFS. Based on the results of the FE model, the coefficient of friction increases by increasing the bending angle and pin diameter; however, these increases are not significant.


      PubDate: 2014-06-14T15:51:09Z
       
  • IFC-Editorial board
    • Abstract: Publication date: September 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 84




      PubDate: 2014-06-14T15:51:09Z
       
  • Warse Klingenberg: A memorial
    • Abstract: Publication date: September 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 84
      Author(s): Trevor Dean



      PubDate: 2014-06-14T15:51:09Z
       
  • IFC - Editorial board
    • Abstract: Publication date: July–August 2014
      Source:International Journal of Machine Tools and Manufacture, Volumes 82–83




      PubDate: 2014-06-14T15:51:09Z
       
  • A novel magnetic actuator design for active damping of machining tools
    • Abstract: Publication date: October 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 85
      Author(s): Fan Chen , Xiaodong Lu , Yusuf Altintas
      Parts and cutting tools with large structural flexibility experience both forced and chatter vibrations during machining, resulting in poor surface finish or damage to the machine. This paper presents the design principles of a novel 3 degrees of freedom linear magnetic actuator which increases the damping and static stiffness of flexible structures during machining. The proposed actuator can deliver 248N force in two radial (x, y) directions and 34N×m (torque) in torsional (θ) direction up to 850Hz. The force and torque reduces to 107N and 14.5N×m at 2000Hz, hence it can actively damp a wide range of structural modes. The magnetic force is linearized with respect to the input current using magnetic configuration design strategy. Loop shaping controllers are designed for active damping of boring bar vibrations. The static and dynamic stiffnesses of the boring bar were considerably increased with the designed actuator, leading to a significant increase in chatter-free material removal rates during cutting tests.


      PubDate: 2014-06-14T15:51:09Z
       
  • The feedrate scheduling of parametric interpolator with geometry, process
           and drive constraints for multi-axis CNC machine tools
    • Abstract: Publication date: October 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 85
      Author(s): Yuwen Sun , Yang Zhao , Jinting Xu , Dongming Guo
      Parametric interpolator has been widely adopted in machining sculptured parts. Accordingly, the feedrate scheduling of parametric interpolator plays a role in CNC machine tools especially for multi-axis machines with linear and rotary axes, since a smooth movement is beneficial for achieving better surface geometry as well as shorter machining time. This paper presents a new feedrate scheduling method for the five-axis machining of geometrically complex part with geometry, process and drive constraints. The satisfaction conditions of constraints are first built and the proportional adjustment of feedrate sensitive regions is proved to be suitable for simultaneously reducing the magnitudes of constraints such as angular acceleration, linear acceleration, axis accelerations and jerks. The initial feedrate profile is first constructed with confined chord error, angular velocity and axis velocities owing to the independence of these constraints. Then, for each iterative adjustment a curve evolution strategy is used to deform the target feedrate profile to the adjusted positions instead of the re-interpolation of feedrate profile, until the final desired feedrate profile is achieved without violated constraints. Simulations and experiments are conducted and the results validate the performances of the proposed method.


      PubDate: 2014-06-14T15:51:09Z
       
  • Modeling and experimental study on micro-fracture behavior and restraining
           technology in micro-grinding of glass
    • Abstract: Publication date: October 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 85
      Author(s): Jun Cheng , Chao Wang , Xuelong Wen , Yadong Gong
      This study presents a new fracture restraining technique for micro-grinding of glass and micro-fracture behavior in micro-grinding of glass is investigated. Penetration depth p 0 and loading force F g of single abrasive are discussed. A predicting model, which quantitatively predicts fracture size l c , is built based on single abrasive micro-interaction theory and elastic strain energy theory. A novel micro-fracture restraining coat, made with resin material, is developed and fabricated onto the work piece׳s surface to provide an extra restraining force for micro-grinding. Experimental machining examples indicate that l cy is reduced from 232.64μm to 32.61μm, and a promotion of 50 times productivity is achieved. Moreover, acrylic resin and epoxy resin are tested for different resins, and it is found that epoxy resin coat provides a ductile mode propelling effect, and acrylic resin coat induces a non-uniform effect which causes a large fracture size and its rapid growth. It is demonstrated that this technology successfully restrains the fracture formation during micro-grinding of glass, and this study proposes the analytical model that captures the main trend of l c results in this experiment. Application of this knowledge is expected to significantly contribute to the precision micro-machining industry of hard–brittle materials.


      PubDate: 2014-06-14T15:51:09Z
       
  • A novel design of brush scrubbing in post-CMP cleaning
    • Abstract: Publication date: October 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 85
      Author(s): Zuqiang Qi , Wanjia Lu , Weiming Lee
      Concentric and eccentric brush scrubbing behaviors of the hard disk drive (HDD) substrates in post-chemical mechanical polishing (CMP) process have been investigated with kinetic brush–disk contact trajectory analysis and hydrodynamic fluid velocity simulation as well as experimental studies. The adhesion forces as well as the hydrodynamic drag force for particle removal are also discussed. The brush nodules–disk contact trajectories with eccentric scrubbing cover the full surface of the disk, however, the trajectories with concentric scrubbing only accumulate on several concentric circular bands aligned along the discrete distribution of brush nodules. The fluid hydrodynamic force with eccentric scrubbing is larger than that with concentric scrubbing. The experimental results have found that the disk surfaces with eccentric scrubbing have approximately 40% lower particle count than that with concentric scrubbing. The modeling analysis and experimental results have found that the eccentric scrubbing has higher particle removal efficiency for the work piece with a hole at the center.


      PubDate: 2014-06-14T15:51:09Z
       
  • Mechanism investigation of friction-related effects in single point
           incremental forming using a developed oblique roller-ball tool
    • Abstract: Publication date: October 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 85
      Author(s): B. Lu , Y. Fang , D.K. Xu , J. Chen , H. Ou , N.H. Moser , J. Cao
      Single point incremental forming (SPIF) is a highly versatile and flexible process for rapid manufacturing of complex sheet metal parts. In the SPIF process, a ball nose tool moves along a predefined tool path to form the sheet to desired shapes. Due to its unique ability in local deformation of sheet metal, the friction condition between the tool and sheet plays a significant role in material deformation. The effects of friction on surface finish, forming load, material deformation and formability are studied using a newly developed oblique roller ball (ORB) tool. Four grades of aluminum sheet including AA1100, AA2024, AA5052 and AA6111 are employed in the experiments. The material deformation under both the ORB tool and conventional rigid tool are studied by drilling a small hole in the sheet. The experimental results suggest that by reducing the friction resistance using the ORB tool, better surface quality, reduced forming load, smaller through-the-thickness-shear and higher formability can be achieved. To obtain a better understanding of the frictional effect, an analytical model is developed based on the analysis of the stress state in the SPIF deformation zone. Using the developed model, an explicit relationship between the stress state and forming parameters is established. The experimental observations are in good agreement with the developed model. The model can also be used to explain two contrary effects of friction and corresponding through-the-thickness-shear: increase of friction would potentially enhance the forming stability and suppress the necking; however, increase of friction would also increase the stress triaxiality and decrease the formability. The final role of the friction effect depends on the significance of each effect in SPIF process.


      PubDate: 2014-06-14T15:51:09Z
       
  • Study on removal mechanism and removal characters for SiC and fused silica
           by fixed abrasive diamond pellets
    • Abstract: Publication date: October 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 85
      Author(s): Zhichao Dong , Haobo Cheng
      Fixed abrasive is known as a high-efficient and stable technique for fabricating various materials. This work studies the removal mechanism and removal characters of fixed abrasive diamond pellets (FADPs) for lapping SiC and fused silica. The critical sizes of diamond particles changing brittle fracture to ductile removal (with better surface roughness and less damages) are figured out for SiC (9.56μm) and fused silica (0.53μm). Multi-distribution models are presented and a mathematical removal model is built based on Preston law. Then, removal characters of FADPs are investigated, including removal profile, removal rate, linear removal, removal stability, surface roughness, subsurface damage etc. Results show that (i) the removal shape is predictable and the removal rate is highly correlative with diamond size, velocity and pressure; (ii) the cumulative removal is temporally linear and removal stability is within ±10%; (iii) SiC can be ductilely lapped by 1.5, 3, 5μm pellets, with best roughness Ra=4.8nm and a specular surface for optical metrology; (iv) removal of fused silica is mostly brittle fracture and it can change as semi-ductile by 1.5μm pellets, with a non-specular or semi-specular surface which is hard for optical metrology; (v) subsurface damage is highly dependent on diamond size, but free to pressure and velocity. Finally, two engineering applications validated its feasibility in uniform or deterministic lapping/polishing of optical mirrors.


      PubDate: 2014-06-14T15:51:09Z
       
  • Rounding and stability in centreless grinding
    • Abstract: Publication date: July–August 2014
      Source:International Journal of Machine Tools and Manufacture, Volumes 82–83
      Author(s): W. Brian Rowe
      The paper presents a method for selecting grinding conditions and assists researchers to understand the complex dynamics of centreless grinding. It overcomes the problem of deriving dynamic stability charts for particular geometries and difficulty of interpreting such charts to adjust work speed to overcome lobing problems. Classic dynamic stability charts cannot assess stability levels in proximity to integer lobes, a particular problem for centreless grinding. The paper overcomes these problems employing a simply calculated new dynamic stability parameter A dyn. The new parameter A dyn simplifies the optimisation of grinding variables including set-up geometry and work speed in relation to resonant frequency. It is difficult to interpret relative dynamic stability of centreless grinding by classical methods for different set-ups, work speeds and numbers of lobes. A new method is employed in this paper based on the well-established Nyquist stability criterion. The dynamic stability parameter A dyn is based on the real part of the characteristic equation. It is easily computed and presented on a single chart for particular work speed, resonant frequency and for a wide range of numbers of lobes. The method clearly shows the effect on rounding strength both for stable and unstable conditions. Most authors computing dynamic stability charts have ignored positive down boundaries and negative up boundaries showing a lack of a comprehensive treatment for a situation that conflicts with recommendations for conventional positive up boundaries. The new method simplifies this problem. Small differences in set-up geometry and work speed selection can be easily assessed. The new method can be used as a diagnostic tool for adjusting grinding conditions to overcome roundness problems. The user is not constrained by a historic set-up range since there are practical situations where other set-ups are preferred such as small tangent angles for large and heavy work-pieces, and even negative tangent angle for some types of centreless machine. Previous research is reviewed to provide an understanding of the need for a new approach to stability. Practical implications are explained for selection of grinding conditions. The method is supported by reference to experimental results.


      PubDate: 2014-04-29T06:51:12Z
       
  • Stiffness design of machine tool structures by a biologically inspired
           topology optimization method
    • Abstract: Publication date: Available online 1 April 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Baotong Li , Jun Hong , Zhifeng Liu
      This paper introduces a novel approach for designing the stiffener layout inside large machine tools by applying the self-optimal growth principle of plant ramifications in nature. Firstly, numerical studies are carried out in order to confirm the potential of leaf venation as concept generators for creating the optimal load-bearing topology for stiffened machine tool structures. Then, a mathematical model explaining the optimality of plant morphogenesis is presented. Based on this, an evolutionary algorithm is developed, which uses three growth strategies to determine the candidate stiffeners to grow or atrophy with respect to the loads applied. The proposed growth-based method could generate a distinct stiffener layout, which is different to those produced by the conventional topology optimization methods, and thus offers unique possibilities for improving the design efficiency and commonality for machine tool development. The suggested approach is finally applied to the re-design of an actual grinding machine column, on which the numerical analyses and experimental tests conducted exemplify the performance enhancement, and therefore is a good choice for the stiffener layout design of machine tool structures.


      PubDate: 2014-04-29T06:51:12Z
       
  • 5-axis Adaptive Flank Milling of Flexible Thin-walled Parts Based on the
           On-machine Measurement
    • Abstract: Publication date: Available online 18 April 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Nuodi Huang , Qingzhen Bi , Yuhan Wang , Chao Sun
      Deformation of the part and cutter caused by cutting forces immediately affects the dimensional accuracy of manufactured parts. This paper presents an integrated machining deviation compensation strategy based on on-machine measurement (OMM) inspection system. Previous research attempts on this topic deal with deformation compensation in machining of geometries in 3-axis machine tools only. This paper is the first time that concerned with 5-axis flank milling of flexible thin-walled parts. To capture the machined surface precision dimensions, OMM with a touch-trigger probe installed on machine's spindle is utilized. Probe path is planned to obtain the coordinate of the sampling points on machined surface. The machined surface can then be reconstructed. Meanwhile, the cutter's envelope surface is calculated based on nominal cutter location source file (CLSF). Subsequently, the machining error caused by part and cutter deflection is calibrated by comparing the deviation between the machined surface and the envelope surface. An iteration toolpath compensation algorithm is designed to decrease machining errors and avoid unwanted interference by modifying the toolpath. Experiment of machining the impeller blade is carried out to validate the methodology developed in this paper. The results demonstrate the effectiveness of the proposed method in machining error compensation.


      PubDate: 2014-04-29T06:51:12Z
       
  • Finite element and experimental studies of the formation mechanism of edge
           defects during machining of SiCp/Al composites
    • Abstract: Publication date: Available online 19 April 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Li Zhou , Yang Wang , ZongYi Ma , Xiaolin Yu
      In this paper, a multi-particle micro finite element model with a random particle distribution in SiCp/Al composites was developed using ABAQUS software. The formation mechanism of edge defects near the exit of orthogonal cutting was analyzed, and the effects of cutting parameters on the sizes of edge defects were investigated. The results indicate that both the brittle fracture of SiC particles and the plastic flow of Al matrix occur in the process of the edge defects formation. Additionally, the cutting speed has little effect on the sizes of edge defects but the cutting depth has a significant effect on the height and length of edge defects. The numerical results were also compared to the orthogonal cutting experimental data and found to be in reasonable agreement.


      PubDate: 2014-04-29T06:51:12Z
       
  • Experimental determination of the tool-chip thermal contact conductance in
           machining process
    • Abstract: Publication date: Available online 23 April 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Vahid Norouzifard , Mohsen Hamedi
      Tool-chip contact is still a challenging issue that affect the accuracy in numerical analysis of machining processes. The tool-chip contact phenomenon can be considered from two points of view: mechanical and thermal contact. Although, there are extensive published literature which addresses the friction modeling of the tool-chip interface, the thermal aspects of the tool-chip contact has not been investigated adequately. In this paper, an experimental procedure is adopted to determine the average thermal contact conductance (TCC) in the tool-chip contact area in machining operation. The tool temperature and the heat flux in tool-chip contact area were determined by inverse thermal solution. Infra-red thermography was also used to measure the average chip temperature near the tool-chip interface. To investigate the effects of the work piece material properties on the tool-chip TCC, AISI 1045, AISI 304 and Titanium materials were considered in the machining experiments. Effects of the cutting parameters such as cutting velocity and feed rate on TCC were also investigated. Evaluating of the tool-chip thermal contact conductance for the tested materials shows that TCC is directly proportional to the thermal conductivity and inversely proportional to the mechanical strength of the work piece. The thermal contact conductance presented in this paper can be used in the future numerical and analytical modeling of the machining process to achieve more accurate simulations of the temperature distribution in the cutting zone and better understanding of the tool-chip contact phenomena.


      PubDate: 2014-04-29T06:51:12Z
       
  • Stability Analysis and Optimization Algorithms for the Set-Up of Infeed
           Centerless Grinding
    • Abstract: Publication date: Available online 21 April 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): D. Barrenetxea , J. Alvarez , J.I. Marquinez , I. Gallego , I. Muguerza Perello , Peter Krajnik
      This paper introduces new algorithms for analysis and optimization of infeed centerless grinding, based on high-level integration of grinding models into a web-based simulation. This holistic approach to simulation facilitates system-level simulation and solvers for several interlinked problems associated with the process mechanics. Emphasis is on structuring the model-based simulation as well as adapting and incorporating the underlying models into the algorithms. Geometric lobing-, chatter- and spinning-related process stability, as well as a time domain continuity equation, are integrated into the simulation to analyze the main quality-related limitations of the process. Once the process stability is assured for the process set-up, optimization strategies and a new infeed cycle definition function are proposed to achieve a minimal or target cycle time. An example of experimental optimization is provided to compare a high-quality process with a target cycle time to an optimized high-productivity process - demonstrating a 70% reduction in cycle time.


      PubDate: 2014-04-29T06:51:12Z
       
  • Conservation Law of Surface Roughness in Single Point Diamond Turning
    • Abstract: Publication date: Available online 28 April 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): W.J. Zong , Y.H. Huang , Y.L. Zhang , T. Sun
      In this work, a comprehensive model is established to predict the surface roughness achieved by single point diamond turning. In addition to the calculation of the roughness components in relation to the kinematics and minimum undeformed chip thickness, the newly developed model also takes the effects of plastic side flow and elastic recovery of materials as machined into account. Moreover, the ‘size effect’ has also been successfully integrated into the model, i.e. that an inflection point appears in the trend line of predicted surface roughness as the ratio of maximal undeformed chip thickness to cutting edge radius (h Dmax/r n) is equal to one unit. Face turning experiments validate that the maximal prediction error is only 13.35%. As the ratio of h Dmax/r n is large than one unit, both the prediction and experiments reveal that a conservation law exists in diamond turned surface roughness, owing to the competitive effects of kinematics, minimum undeformed chip thickness, plastic side flow and elastic recovery of materials on surface formation. Under the conservation law, the freedom control for an invariable surface roughness can be fulfilled in response to a quantitative ratio of h Dmax/r n, either through an accurate configuration of feed rate and depth of cut with fixed tool nose radius and cutting edge radius, or by a reasonable selection of tool nose radius and controlled cutting edge radius with designed feed rate and depth of cut.


      PubDate: 2014-04-29T06:51:12Z
       
  • Identification of the specific cutting force for geometrically defined
           cutting edges and varying cutting conditions
    • Abstract: Publication date: July–August 2014
      Source:International Journal of Machine Tools and Manufacture, Volumes 82–83
      Author(s): Berend Denkena , Jost Vehmeyer , Daniel Niederwestberg , Peter Maaß
      Cutting force modeling is a major discipline in the research of cutting processes. The exact prediction of cutting forces is crucial for process characterization and optimization. Semi-empirical and mechanistic force models have been established, but the identification of the specific cutting force for a pair of tool and workpiece material is still challenging. Existing approaches are depending on geometrical idealizations and on an extensive calibration process, which make practical and industrial application difficult. For nonstandard tools and five axis kinematics there does not exist a reasonable solution for the identification problem. In this paper a co-operative force model for the identification of the specific cutting forces and prediction of integral forces is presented. The model is coupled bidirectionally with a multi-dexel based material removal model that provides geometrical contact zone information. The nonlinear specific forces are modeled as polynomials of uncut chip thickness. The presented force model is not subjected to principal restrictions on tool shape or kinematics, the specific force and phase shift are identified with help of least square minimization. The benefit of this technique is that no special calibration experiments are needed anymore, which qualifies the method to determine the specific forces simultaneously during the machining process. In this paper, experiments with different cutting conditions are analyzed and systematically rated. Finally, the method is validated by experiments using different cutting conditions.


      PubDate: 2014-04-29T06:51:12Z
       
  • Ballbar dynamic tests for rotary axes of five-axis CNC machine tools
    • Abstract: Publication date: July–August 2014
      Source:International Journal of Machine Tools and Manufacture, Volumes 82–83
      Author(s): Wei-Tai Lei , Wen-Chung Wang , Tien-Ching Fang
      This paper proposes a new ball bar test method for the inspection of dynamic errors of rotary axes in five-axis CNC machine tools. The test circle is defined in a workpiece coordinate system and the ball bar test is performed by simultaneously driving of linear–rotary axis couple. The effects of the center position and the radius on the setting values, rotational range and measurement sensitivity of the rotary axis were investigated. The proposed ball bar test is performed in two steps: the circular positioning and the circular tracking with a continuous feed. Axial dynamic errors are obtained by subtracting the measured tracking errors from the positioning errors. A ball bar test system (BBTS) was developed to plan the tool path and the tool orientation, to communicate with the five-axis CNC controller and to process the measured data. Error patterns were simulated regarding the gain mismatch, backlash and tracking direction to help a fast diagnosis of the error sources. Simulations and experimental results prove the effectiveness of the new test method.


      PubDate: 2014-04-29T06:51:12Z
       
  • Characteristics of stiffness and contact stress distribution of a
           spindle–holder taper joint under clamping and centrifugal forces
    • Abstract: Publication date: July–August 2014
      Source:International Journal of Machine Tools and Manufacture, Volumes 82–83
      Author(s): Chao Xu , Jianfu Zhang , Pingfa Feng , Dingwen Yu , Zhijun Wu
      An understanding of the contact characteristics of a spindle–holder joint in machine tools calls for an in-depth analysis of its performance under machining conditions. This study specifically aims to model a spindle–holder taper joint to predict the stiffness and stress distribution under different clamping and centrifugal forces. A spindle–holder taper joint subjected to clamping and centrifugal forces was modeled using the finite element method. The stress distribution of the interface was revealed and it was found that the von-Mises stress had a non-linear distribution because of the clamping force of the holder. The centrifugal forces were included in the model to analyze the deformation of the joint. At high speed the centrifugal force caused a stress concentration at the large end of the holder. A typical 7/24 taper joint of a BT50 holder was investigated to identify the stiffness using a special experimental platform. The axial and radial stiffnesses, as well as the hysteresis cycles were obtained to predict the contact characteristics with different clamping forces. The experimental results showed that the model presented in this study was efficient in predicting the characteristics of the spindle–holder joint. The method presented is useful in identifying the dynamics of a spindle–holder and can thus be used to optimize the spindle system.


      PubDate: 2014-04-29T06:51:12Z
       
  • A thermal error model for large machine tools that considers environmental
           thermal hysteresis effects
    • Abstract: Publication date: July–August 2014
      Source:International Journal of Machine Tools and Manufacture, Volumes 82–83
      Author(s): Bo Tan , Xinyong Mao , Hongqi Liu , Bin Li , Songping He , Fangyu Peng , Ling Yin
      Environmental temperature has an enormous influence on large machine tools with regards to thermal deformation, which is different from the effect on ordinary-sized machine tools. The thermal deformation has hysteresis effects due to environmental temperature, and the hysteresis time fluctuates with seasonal weather. This paper focused on the hysteresis nonlinear characteristic, analyzing the thermal effect caused by external heat sources. Fourier synthesis, time series analysis and the Newton cooling law were combined to build a time-varying analytical model between environmental temperature and the corresponding thermal error for a large machine tool. A multiple linear regression model based on the least squares principle was used to model the internal heat source effects simultaneously. The two models were united to make up a synthetic thermal error prediction model called the environmental temperature consideration prediction model (ETCP model). A series of experiments were performed using a large gantry type machine tool to verify the accuracy and efficiency of the predicted model under random environments, random times and random machining conditions throughout an entire year. The proposed model showed high robustness and universality, with over 85% thermal error, with up to 0.2mm was predicted. The mathematical model was easily integrated into the NC system and could greatly reduce the thermal error of large machine tools under ordinary workshop conditions, especially for long-period cycle machining.


      PubDate: 2014-04-29T06:51:12Z
       
 
 
JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327
 
About JournalTOCs
API
Help
News (blog, publications)
JournalTOCs on Twitter   JournalTOCs on Facebook

JournalTOCs © 2009-2014