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  Subjects -> MANUFACTURING AND TECHNOLOGY (Total: 258 journals)
    - CERAMICS, GLASS AND POTTERY (24 journals)
    - MACHINERY (32 journals)
    - MANUFACTURING AND TECHNOLOGY (155 journals)
    - METROLOGY AND STANDARDIZATION (3 journals)
    - PACKAGING (14 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: 11)
Applied Mechanics Reviews     Full-text available via subscription   (Followers: 20)
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: 6)
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: 3)
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: 2)
Journal of Mechanics     Hybrid Journal   (Followers: 16)
Journal of Strain Analysis for Engineering Design     Hybrid Journal   (Followers: 3)
Journal of Terramechanics     Hybrid Journal   (Followers: 1)
Machine Design     Partially Free   (Followers: 6)
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
   [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]
  • 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
       
  • IFC - Editorial board
    • Abstract: Publication date: March 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 78




      PubDate: 2014-04-29T06:51:12Z
       
  • Fine finishing of internal surfaces using elastic abrasives
    • Abstract: Publication date: March 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 78
      Author(s): V.S. Sooraj , V. Radhakrishnan
      The paper describes a simple and innovative approach of using elastic abrasives for generating ultra fine finish on internal surfaces of tubular specimens. Elastic abrasive is a unique concept of using abrasive embedded elastomeric balls having the special capability to deform in conformity to work surface and thereby imparting a very fine refinement of its profile without altering the form. The mechanism of material removal in the proposed methodology is analysed using a mathematical model and its validation was done using a systematic experimentation procedure. Response surface methodology using central composite design is applied for the experimental study to investigate the effect of axial pressure, abrasive grain size and longitudinal stroke velocity of elastic abrasives on the surface finish. The process discussed in this paper is a simple and cost effective option to produce micro/nano-finish on the internal surfaces of a wide range of industrial components including hollow specimens, high aspect ratio bores and sleeves.


      PubDate: 2014-04-29T06:51:12Z
       
  • A macroscopic mechanical model of wire electrode deflection considering
           temperature increment in MS-WEDM process
    • Abstract: Publication date: March 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 78
      Author(s): Guojun Zhang , Zhi Chen , Zhen Zhang , Yu Huang , Wuyi Ming , He Li
      In medium-speed wire electrical discharge machining (MS-WEDM), wire in the area near the guide wheel and between the two guide wheels obviously form the wire bending deformation due to wire tension, electrostatic force, electrodynamics force, hydrodynamic force, temperature increment, etc. Besides, the wire deflection would have a direct influence on the machining accuracy, productivity and stability. In this paper, first of all, main causes of wire electrode deformation are proposed to better understand its fundamental mechanism. Second, two macroscopic mechanical models of wire deflection are developed in the area near the guide wheel and between the two guide wheels considering temperature increment and wire vibration in machining 20mm-thickness workpiece process, respectively. Moreover, the numerical solution of deflection in the area near the guide wheel and the theoretical solution of deflection between the two guide wheels has been worked out. Then, the analysis of the variation trend of wire deflection and the influences of wire deflection on the machining process have been conducted. Eventually, from the confirmation experiment and comparison with other researchers’ models, it has been proved that the macroscopic mechanical models of wire deflection in MS-WEDM process are reasonable and reliable. In addition, according to macroscopic mechanical models, some of the practical approaches of reducing wire deflection have been proposed to improve machining accuracy, and these high-precision models can be applied into NC system to set a compensation for wire deflection in the future.


      PubDate: 2014-04-29T06:51:12Z
       
  • 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
       
  • Material removal behavior in ultrasonic-assisted scratching of SiC
           ceramics with a single diamond tool
    • Abstract: Publication date: April 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 79
      Author(s): Jianguo Cao , Yongbo Wu , Dong Lu , Masakazu Fujimoto , Mitsuyoshi Nomura
      Ultrasonic-assisted grinding (UAG) has been extensively employed in manufacturing industries for processing hard and brittle materials. However, its potential has not been sufficiently developed because the material removal mechanism in UAG has not been elucidated. This paper focuses on the material removal mechanism in the UAG of silicon carbide (SiC) ceramics by investigating the material removal behaviors in ultrasonic-assisted scratching (UAS) of SiC ceramics. The UAS test was conducted on an NC (Numerical Control) surface grinder connected to a self-designed ultrasonic unit; a single diamond tool was fixed onto the end-face of the ultrasonic unit to achieve an ultrasonic vibration (UV). Conventional scratching (CS) test was also carried out on the same experimental rig but without UV for comparison. During testing, the material deformation/fracture behavior and the scratching forces were investigated. The experimental results show that (1) there are two scratching modes in the UAS process depending on actual depth of cut: an intermittent mode and a continuous mode; (2) the mean groove depth in UAS is much bigger than that in CS, indicating that the cutting ability of the tool was significantly improved by the assistance of the UV; (3) the critical depth of cut is increased by 56.25% once UV is applied; the stiffness of the experiment setup is improved in the UAS compared to CS; the UV in y-direction strongly contributes to the material removal, whereas the UV in z-direction only results in variation of the cutting trace and hardly contributes to the material removal in the UAS process; (4) in UAS, the scratching forces sinusoidally fluctuate with the same period as that of the UV of the tool when the material removal is in ductile mode, when the material removal is in brittle mode, the forces heavily vary but the period is different from that of the UV of the tool; (5) the cutting efficiency of the tool is improved by the assistance of the UV. The impact and cutting action at the tool tip on the machining surface are the main factors contributing to the material removal. The observed features were rationalized by analyzing kinematic characteristics of the tool and material removal mechanism in UAS. This study confirms that UAG is a highly effective processing method for machining hard and brittle materials.


      PubDate: 2014-04-29T06:51:12Z
       
  • Least squares approximated stability boundaries of milling process
    • Abstract: Publication date: April 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 79
      Author(s): C.G. Ozoegwu
      First and second order least squares methods are used in generating simple approximation polynomials for the state term of the model for regenerative chatter in the milling process. The least squares approximation of delayed state term and periodic term of the model does not go beyond first order. The resulting discrete maps are demonstrated to have same convergence rate as the discrete maps in other works that are based on the interpolation theory. The presented discrete maps are illustrated to be beneficial in terms of computational time (CT) savings that derive from reduction in the number of calculation needed for generation system monodromy matrix. This benefit is so much that computational time of second order least squares-based discrete map is noticeably shorter than that of first order interpolation-based discrete map. It is expected from analysis then verified numerically that savings in CT due to use of least squares theory relative to use of interpolation theory of same order rises with rise in order of approximation. The experimentally determined model parameters used for numerical calculations are extracted from literature.


      PubDate: 2014-04-29T06:51:12Z
       
  • Research on the Chip Formation Mechanism during the high-speed milling of
           hardened steel
    • Abstract: Publication date: April 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 79
      Author(s): Chengyong Wang , Yingxing Xie , Lijuan Zheng , Zhe Qin , Dewen Tang , Yuexian Song
      An easy-to-produce sawtooth chip is the main feature of the high-speed milling process for hardened steel. This chip may lead to a high-frequency periodic fluctuation of the cutting force and accelerate the tool׳s wear rate. This study investigated the process of chip formation and the change in chip morphology during the high-speed milling of hardened steel (51, 62HRC). The formation condition of continuous and sawtooth chips and various characteristics of the sawtooth chip, such as cutting speed, feed rate, axial depth of cut, and others, were also studied. The results showed that the chip of materials with different hardnesses could be controlled as a continuous chip through the optimisation of a combination of cutting speed, feed per tooth, and cutting depth. If the feed per tooth and axial depth of the cut were too large within the range of proper cutting speeds generated by a continuous chip, the chip morphology turned into a sawtooth. Increasing the cutting speed during the cutting process not only strengthened the material׳s hardness but also increased the local temperature of the shear band rapidly and aggravated the material׳s heat softness. When these parameters became balanced, the shear deformation became highly localised in the shear band and resulted in adiabatic shear. A quantitative evaluation of the sawtooth-shaped chip׳s deformation degree was performed using the cross-sectional area and angle of the sawtooth chip. By establishing a geometric model of the sawtooth chip formation during the high-speed milling of hardened steel, that was used to predict the shear strain and strain rate during chip formation, the range of shear angles generating a sawtooth chip was calculated to be 40–60°.


      PubDate: 2014-04-29T06:51:12Z
       
  • A Hydrodynamic and Kinematic Analysis of Chemical Mechanical Planarization
           Mechanism in Double Sided Polisher
    • Abstract: Publication date: Available online 14 April 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Zuqiang Qi , Wanjia Lu , Weiming Lee
      In this study, a hydrodynamic and kinematic analysis of the double sided chemical-mechanical planarization (CMP) mechanism is discussed. The workpieces are disk substrates with a hole at the center. The hydrodynamic results show that the disk surface has a positive fluid pressure zone and a negative pressure zone. The positive pressure zone squeezes out the used slurry and the negative pressure zone sucks in the fresh slurry. The high pressurized slurry with abrasive particles has a significant interaction with the disk surface and removes the material. The self rotation of the disks inside the carriers is beneficial for the uniformity and global planarization of the disks. The kinematic analysis results show that a transient center of the carriers exists and the velocity magnitude and direction change abruptly at this position. It should be avoided on the disk surface, because such a transient center is a halt point which may cause defects on the disk surface. The velocity at the carrier center is steady, but the velocity at the carrier edge has a larger oscillation with a higher average number. The critical waviness and surface integrity can be optimized via the kinematic parameters by the abrasive particle trajectories on the disk surface.


      PubDate: 2014-04-29T06:51:12Z
       
  • IFC - Editorial board
    • Abstract: Publication date: April 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 79




      PubDate: 2014-04-29T06:51:12Z
       
  • A general approach for error modeling of machine tools
    • Abstract: Publication date: April 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 79
      Author(s): Wenjie Tian , Weiguo Gao , Dawei Zhang , Tian Huang
      This paper presents a general and systematic approach for geometric error modeling of machine tools due to the geometric errors arising from manufacturing and assembly. The approach can be implemented in three steps: (1) development of a linear map between the pose error twist and source errors within machine tool kinematic chains using homogeneous transformation matrix method; (2) formulation of a linear map between the pose error twist and the error intensities of a machine tool; (3) combination of these two models for error separation. The merit of this approach lies in that it enables the source errors affecting the compensatable and uncompensatable pose accuracy of the machine tool to be explicitly separated, thereby providing designers and/or field engineers with an informative guideline for the accuracy improvement by suitable measures, i.e. component tolerancing in design, manufacturing and assembly processes, and error compensation. Two typical multi-axis machine tools are taken as examples to illustrate the generality and effectiveness of this approach.


      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
       
  • The effects of design parameters on the laser-induced in-plane deformation
           of two-bridge actuators
    • Abstract: Publication date: May–June 2014
      Source:International Journal of Machine Tools and Manufacture, Volumes 80–81
      Author(s): Jacek Widłaszewski
      Laser-based non-contact micro-adjustment method is a way of going beyond limits of traditional mechanical techniques applied for precise alignment during assembly of miniature opto-electro-mechanical devices. The two-bridge actuator is an on-board structure that allows for adjustments with micrometer, sub-micrometer or sub-miliradian accuracy. Successful industrial application of the method requires a thorough understanding of mechanics of the laser-induced deformation process. The effects of two fundamental design parameters, i.e., the width and the distance between the bridges, on in-plane plastic deformation of the actuator are examined in this work. Experimentally validated theoretical model explains how design parameters, material data and laser pulse parameters affect the final deformation angle of the actuator. The derived mathematical formulae show dependence of the constraint ratio, thermal stresses and thermally-induced plastic deformation on the design parameters of the structure. The proposed solution can be used for optimization of two-bridge actuators.


      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
       
  • Modeling of microcrack formation in orthogonal machining
    • Abstract: Publication date: May–June 2014
      Source:International Journal of Machine Tools and Manufacture, Volumes 80–81
      Author(s): Dattatraya Parle , Ramesh K. Singh , Suhas S. Joshi , G.V.V. Ravikumar
      Researchers have observed formation of microcracks during metal cutting and attributed their occurrence to various phenomena. Shaw postulated that under the combined shear and normal stress conditions on shear plane, microcracks could occur when strain in the shear plane exceeds the failure limit of material. However, the phenomenon of microcrack formation is difficult to capture experimentally. Therefore, this paper presents a finite element (FE) model to simulate the microcrack formation during orthogonal cutting. The model has been validated by performing orthogonal micro-cutting experiments and error in cutting force prediction is less than 11.5%. The simulation helps identify locations at which microcracks are formed in the shear zone using the mathematical and FEA models. Furthermore, the contribution of the specific energy (energy/volume) associated with the microcrack formation to the total specific energy of the shear zone has been evaluated. Contribution of microcracks to specific shear zone energy is found to be in the range of 0–20% for AISI 1215 and 0–15% for AISI 1045 under different machining conditions.


      PubDate: 2014-04-29T06:51:12Z
       
  • The relation between chip morphology and tool wear in ultra-precision
           raster milling
    • Abstract: Publication date: May–June 2014
      Source:International Journal of Machine Tools and Manufacture, Volumes 80–81
      Author(s): Guoqing Zhang , Suet To , Gaobo Xiao
      In the field of ultra-precision machining, the study of the relation between chip morphology and tool wear is significant, since tool wear characteristics can be reflected by morphologies of cutting chips. In this research, the relation between chip morphology and tool flank wear is first investigated in UPRM. A cutting experiment was performed to explore chip morphologies under different widths of flank wear land. A geometric model was developed to identify the width of flank wear land based on chip morphology. Theoretical and experimental results reveal that the occurrence of tool flank wear can make the cutting chips truncated at both their cut-in and cut-out sides, and reduce the length of cutting chips in the feed direction. The width of truncation positions of the cutting chip can be measured and used to calculate the width of flank wear land with the help of the mathematical model. The present research is potentially used to detect tool wear and evaluate machined surface quality in intermittent cutting process.
      Graphical abstract image

      PubDate: 2014-04-29T06:51:12Z
       
  • IFC - Editorial board
    • Abstract: Publication date: May–June 2014
      Source:International Journal of Machine Tools and Manufacture, Volumes 80–81




      PubDate: 2014-04-29T06:51:12Z
       
  • On the mechanics and material removal mechanisms of vibration-assisted
           cutting of unidirectional fibre-reinforced polymer composites
    • Abstract: Publication date: May–June 2014
      Source:International Journal of Machine Tools and Manufacture, Volumes 80–81
      Author(s): Weixing Xu , L.C. Zhang
      This paper aims to reveal the material removal mechanisms and the mechanics behind the vibration-assisted cutting (VAC) of unidirectional fibre reinforced polymer (FRP) composites. Through a comprehensive analysis by integrating the core factors of the VAC, including fibre orientation and deformation, fibre–matrix interface, tool–fibre contact and tool–workpiece contact, a reliable mechanics model was successfully developed for predicting the cutting forces of the process. Relevant experiments conducted showed that the model has captured the mechanics and the major deformation mechanisms in cutting FRP composites, and that the application of ultrasonic vibration in either the cutting or normal direction can significantly decrease cutting forces, minimise fibre deformation, facilitate favourable fibre fracture at the cutting interface, and largely improve the quality of a machined surface. When the vibrations are applied to both the cutting and normal directions, the elliptic vibration trajectory of the tool tip can bring about an optimal cutting process. There exists a critical depth of cut, beyond which the fibre–matrix debonding depth is no longer influenced by the vibration applied on the tool tip.


      PubDate: 2014-04-29T06:51:12Z
       
  • Extension of Tlusty׳s law for the identification of chatter
           stability lobes in multi-dimensional cutting processes
    • Abstract: Publication date: July–August 2014
      Source:International Journal of Machine Tools and Manufacture, Volumes 82–83
      Author(s): Andreas Otto , Stefan Rauh , Martin Kolouch , Günter Radons
      Chatter vibrations in cutting processes are studied in the present paper. A unified approach for the calculation of the stability lobes for turning, boring, drilling and milling processes in the frequency domain is presented. The method can be used for a fast and reliable identification of the stability lobes and can take into account nonlinear shearing forces, as well as process damping forces. The applicability of Tlusty׳s law, which is a simple scalar relationship between the real part of the oriented transfer function of the structure and the limiting chip width, is extended to milling and any other multi-dimensional chatter problem without neglecting the coupled dynamics. The given analysis is suitable for getting a deep understanding of the chatter stability dependent on the parameters of the cutting process and the structure. Basic examples based on experimental data of real machine tools include the dependence of the stability behavior on the rotational direction in turning, the effect of axial–torsional structural coupling in drilling, and the dynamics of slot milling.


      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
       
  • Receptance coupling for tool point dynamic prediction BY fixed boundaries
           approach
    • Abstract: Publication date: Available online 8 January 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Iker Mancisidor , Aitor Urkiola , Rafael Barcena , Jokin Munoa , Zoltan Dombovari , Mikel Zatarain
      The material removal capability of machines is partially conditioned by self-excited vibrations, also known as chatter. In order to predict chatter free machining conditions, dynamic transfer function at the tool tip is required. In many applications, such as high-speed machining (HSM), the problematic modes are related to the flexibility of the tool, and experimental calculation of the Frequency Response Function (FRF) should be obtained considering every combination of tool, toolholder and machine. Therefore, it is a time consuming process which disturbs the production. The bibliography proposes the Receptance Coupling Substructure Analysis (RCSA) to reduce the amount of experimental tests. In this paper, a new approach based on the calculation of the fixed boundary dynamic behaviour of the tool is proposed. Hence, the number of theoretical modes that have to be considered is low, instead of the high number of modes required for the models presented up today. This way, the Timoshenko beam theory can be used to obtain a fast prediction. The accuracy of this new method has been verified experimentally for different tools, toolholders and machines.


      PubDate: 2014-01-11T15:46:57Z
       
  • Heating and material removal process in hybrid laser-waterjet ablation of
           silicon substrates
    • Abstract: Publication date: Available online 7 January 2014
      Source:International Journal of Machine Tools and Manufacture
      Author(s): V. Tangwarodomnukun , J. Wang , C.Z. Huang , H.T. Zhu
      A hybrid laser-waterjet micromachining technology has recently been developed for near damage-free micro-ablation. It uses a laser to heat and soften the target material and a waterjet to expel the laser-softened elemental material to decrease thermal damages and increase the material removal. A computational model for the hybrid laser-waterjet micro-grooving process for single crystalline silicon is presented in this paper using an enthalpy-based finite difference method. Laser heating and waterjet cooling and expelling with the temperature-dependent silicon properties are considered in the model to predict the temperature profiles of silicon and groove characteristics under different machining conditions. The simulation results show that the introduction of a high pressure waterjet enables to remove material at its soft-solid status much below its melting temperature, while the waterjet cooling effect can reduce the workpiece temperature during the laser non-pulse period and eliminate the effect of heat accumulation, so that the thermal damage induced by laser heating is minimized. The temperature field model is also used to predict the groove depth and profile, and it is found that the model can reasonably represent the machined groove characteristics when comparing to the experimental data.


      PubDate: 2014-01-11T15:46:57Z
       
  • IFC - Editorial board
    • Abstract: Publication date: February 2014
      Source:International Journal of Machine Tools and Manufacture, Volume 77




      PubDate: 2013-12-30T10:14:11Z
       
  • An Examination of the Fundamental Mechanics of Cutting Force Coefficients
    • Abstract: Publication date: Available online 21 December 2013
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Minghai Wang , Lei Gao , Yaohui Zheng
      In metal cutting, the cutting force is the key factor affecting the machined surface, and is also important in determining reasonable cutting parameters. The research and construction of cutting force prediction models therefore has great practical value. The accuracy of cutting force prediction largely depends on the cutting force coefficients of the material. In the average cutting force model, cutting force coefficients are considered to be constant. This study makes use of experiments to investigate the cutting force coefficients in the average cutting force model, with a view to accurately identifying cutting force coefficients and verifying that they are related only to the tool-workpiece material couple and the tool geometrical parameters, and are not affected by milling parameters. To this end, the paper first examines the theory behind identifying cutting force coefficients in the average cutting force model. Based on this theory, a series of slot-milling experiments are performed to measure the milling forces, fixing spindle speeds and radial/axial depths of cutting, and linearly varying the feed per tooth. The tangential milling force coefficient and the radial milling force coefficient are then calculated by linearly fitting the experimental data. The obtained results show that altering the milling parameters does not change the milling force coefficients for the selected tool/workpiece material combination.
      Graphical abstract image

      PubDate: 2013-12-23T03:05:09Z
       
  • A novel spindle inclination error identification and compensation method
           in ultra-precision raster milling
    • Abstract: Publication date: Available online 21 December 2013
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Guoqing Zhang , Suet To , Gaobo Xiao
      In the ultra-precision raster milling (UPRM) process, the existence of spindle inclination error can directly affect the dimensional accuracy of machined components. This study developed a novel spindle inclination error identification and compensation method based on the groove cutting in UPRM. In this method, the tilt angle of the intersection curve of two toruses (ICTT) generated from two neighboring rotary cuts in UPRM was measured to identify the spindle inclination error. A mathematical model was developed to simulate the ICTT profile and present the relationship between the tilt angle of ICTTs and the spindle inclination error by solving the differential of the ICTT function, by which the spindle inclination error can be solved under the given cutting parameters and the tilt angle of ICTTs. The effects of cutting parameters on the tilt angle of ICTTs were explored. An error compensation procedure was designed and a group of groove cutting experiments was conducted to identify and compensate the spindle inclination error. The theoretical and experimental results show that the proposed method can compensate for the spindle inclination error effectively and accurately.


      PubDate: 2013-12-23T03:05:09Z
       
  • Simulation model of debris and bubble movement in consecutive-pulse
           discharge of electrical discharge machining
    • Abstract: Publication date: Available online 11 November 2013
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jin Wang , Fuzhu Han
      Debris concentration and bubble volume fraction in the bottom gap between the electrode and workpiece affects the state of consecutive-pulse discharge and the efficiency of electrical discharge machining (EDM). Thus, the mechanisms of debris and bubble movement during consecutive-pulse discharge should be elucidated. However, these mechanisms have not been fully understood because of debris and bubble movement in the machining gap is difficult to simulate and observe. This study proposes a three-dimensional model of flow field with liquid, gas, and solid phases for machining gap in EDM. The mechanisms of debris and bubble movement in the machining gap during consecutive-pulse discharge were analyzed through the model. Debris and bubble movement in consecutive-pulse discharge was observed through experiments. The results showed that the proposed simulation model is feasible. The bubble expansion is the main way that the bubbles exclude from machining gap. Much debris moves outside the machining gap following the excluded bubbles, which is the main way that the debris excludes from machining gap. The bubble expansion becomes strong with the increase of the discharge current and pulse-on time.
      Graphical abstract image

      PubDate: 2013-11-12T09:26:46Z
       
  • Further insight into the chip formation of ferritic-pearlitic steels:
           Microstructural evolutions and associated thermo-mechanical loadings
    • Abstract: Publication date: Available online 6 November 2013
      Source:International Journal of Machine Tools and Manufacture
      Author(s): C. Courbon , T. Mabrouki , J. Rech , D. Mazuyer , F. Perrard , E. D'Eramo
      The main objective of this paper is to clarify the deformation mechanisms of ferritic-pearlitic steels in metal cutting and correlate them to the associated thermo-mechanical loadings. Dry orthogonal cutting tests have been performed on a normalized AISI 1045 steel with coated carbide tools. Experimental evidences of a drastic grain refinement process in the main deformation zones are advanced on the basis of optical microscope, field emission scanning electron microscope (FESEM) and Electron BackScaterred Diffraction (EBSD). Microstructural evolutions leading to a grain size down to 200nm and fragmented cementite are especially emphasised. A numerical approach is further employed to target and quantify the loadings applied to the machined material and extract further information on the Secondary Shear Zone (SSZ). Strains amplitude appears to be the driving parameter of these evolutions via a dynamic recrystallization process promoted by an intense and localised heat generation. The present contribution highlights that in-depth and micro scale investigations of chip formation including microstructural aspects are still required.


      PubDate: 2013-11-09T04:54:44Z
       
  • A Novel Approach to Machining Condition Monitoring of Deep Hole Boring
    • Abstract: Publication date: Available online 7 November 2013
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Wenrong Xiao , Yanyang Zi , Binqiang Chen , Bing Li , Zhengjia He
      In the optimization of deep hole boring processes, machining condition monitoring (MCM) plays an important role for efficient tool change policies, product quality control and lower tool costs. This paper proposes a novel approach to the MCM of deep hole boring on the basis of the pseudo non-dyadic second generation wavelet transform (PNSGWT). This approach is developed via constructing a valuable indicator, i.e., the wavelet energy ratio around the natural frequency of boring bar. Self-excited vibration occurs at the frequency of the most dominant mode of the machine tool structure. Via modeling dynamic cutting process and performing its simulation analysis during deep hole boring, it is found that the vibration amplitudes in the nature frequency of the machine tool rise with the tool wear. The PNSGWT that has relative adjustable dyadic time-frequency partition grids, good time-frequency localizability and exact shift-invariance is used to extract the wavelet energy in the specified frequency band. Accordingly, the MCM of deep hole boring can be implemented by means of normalizing the wavelet energy. Finally, a field experiment on deep hole boring machine tool is conducted, and the result shows that the proposed method is effective in the process of monitoring tool wear and surface finish quality for deep hole boring.


      PubDate: 2013-11-09T04:54:44Z
       
  • On the mechanics of chip formation in Ti6Al4V turning with spindle speed
           variation
    • Abstract: Publication date: Available online 1 November 2013
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Elio Chiappini , Stefano Tirelli , Paolo Albertelli , Matteo Strano , Michele Monno
      Titanium alloys are hard-to-cut materials and need to be machined at relatively low cutting speeds with obvious negative consequences on the profitability of machining. In order to enhance material removal rate (MRR), a strategy that relies on higher depths of cut could be chosen if vibrational issues due to regenerative chatter did not occur. A lot of research was done to suppress regenerative chatter without detrimental effects on productivity. One of the most interesting chatter suppression methods, mainly due to its flexibility and relative ease of implementation, is spindle speed variation (SSV), which consists in a continuous modulation of the nominal cutting speed. Sinusoidal spindle speed variation (SSSV) is a specific technique that exploits a sinusoidal law to modulate the cutting speed. The vast scientific literature on SSV was mainly focused on cutting process stability issues fully neglecting the study of the mechanics of chip formation in SSV machining. The aim of this work is to fill this gap: thus, finite element method (FEM) models of Ti6Al4V turning were setup to simulate both SSSV and constant speed machining (CSM). The models consider both the micro-geometry of the insert and the coating. Numerical results were experimentally validated on dry turning tests of titanium tubes exploiting the experimental assessment of cutting forces, cutting temperatures and chip morphology. Tool-chip contact pressure, tool engagement mechanism and the thermal distribution in the insert are some of the analysed numerical outputs because they cannot be easily assessed by experimental procedures. These quantities were useful to compare thermo-mechanical loads of the insert both in CSM and SSSV machining: it was observed that the loads significantly differ. Compared to CSM, the modulation of the cutting speed involves a higher tool-chip contact pressure peak, a higher maximum temperature and higher temperature gradients that could foster the main tool wear mechanisms.


      PubDate: 2013-11-04T20:05:20Z
       
  • Experimental Study of Surface Generation and Force Modeling in
           Micro-grinding of Single Crystal Silicon Considering Crystallographic
           Effects
    • Abstract: Publication date: Available online 30 October 2013
      Source:International Journal of Machine Tools and Manufacture
      Author(s): J. Cheng , Y.D. Gong
      In this study, surface formation mechanism in micro-grinding of single crystal silicon is investigated based on analysis of undeformed chip thickness h m . A predicting model of grinding force considering crystallographic effects in micro-grinding of single crystal silicon is built. In this model, micro-grinding process of single crystal silicon is divided into two steps by one line on which h m of single grit equals to lattice constant. Two micro-grinding experiments with different ranges of cutting depths and feed rates have been designed and conducted on single crystal silicon to verify the model this paper proposes. The relationship between micro-grinding parameters and crack length l c is investigated and the empirical formula of l c is derived based on analysis of experiment results. Ductile-regime transitions in micro-grinding process of single crystal silicon have been revealed, 20nm and 100nm are turned out to be two critical conditions based on analysis of experiment results. It is found that the grinding force has a sudden change when micro-grinding process comes within material's crystal boundary in experiment. The force predicting model this paper proposes has well explained this phenomenon in micro-grinding of single cyrstal silicon. When micro-grinding undeformed chip thickness h m belows 0.5nm, micro grinding force doesn't decrease with the decrease of cutting parameters but has a rising tendency, and these experimental measurements also provide a support to the result of model this paper proposes.


      PubDate: 2013-11-01T03:06:00Z
       
  • Geometric Error Measurement and Identification for Rotary Table of
           Multi-axis Machine tool Using Double Ballbar
    • Abstract: Publication date: Available online 28 October 2013
      Source:International Journal of Machine Tools and Manufacture
      Author(s): Jian-xiong Chen , Shu-wen Lin , Bing-wei He
      In this paper, comprehensive geometric errors, including linkage errors and volumetric errors, of a rotary table are measured totally by employing a double ballbar and obtained by a two-step identification procedure. The derivations of the center of the ball installed on the table are measured in the error sensitive directions with newly developed serial of two axes controlled circular paths. Hence, there are nine results measured from three mounting positions of the ball at the same rotation angle. These results are used to form the identification model based on the homogeneous transformation. Moreover, a sensitive analysis method is applied to select the optimum installation parameters of the ballbar to diminish the influence of the inaccuracy of the measurement parameters. As the mounting position errors of the socket on the table are inevitable during the installation of the balls, a new correction procedure is developed as well. Finally, an experiment is conducted on the four-axis machining center. The comparison results between the predicted errors and the measured results are shown to verify the proposed method.


      PubDate: 2013-11-01T03:06:00Z
       
 
 
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