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Key engineering materials
Trans Tech Publications Ltd.
Key engineering materials

Trans Tech Publications Ltd.

半月刊

1013-9826

Key engineering materials/Journal Key engineering materials
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    Research of Gyroscopic Effects on the Stability of High Speed Milling

    Xiqing XuWeixiao TangShanshan Sun
    p.369-372页
    查看更多>>摘要：High-speed milling (HSM) which is characterized as high productivity and low power consumption can be widely used in the manufacture industry. However, while the speed of spindle-tool reach the high speed range, the prediction of its stable milling faces more difficulties, as the gyroscopic effects become prominent. In this paper, a dynamics model of HSM system was set up considering the influence of gyroscopic moment due to high rotating speed of spindle-tool. Then a method was proposed by transforming time-varying stiffness system into fixed-step time invariant one. Finally the stability lobes diagrams (SLD) was elaborated. The results shows that the gyroscopic effects due to high rotating speed have non-negligible impact on the stability limitation, which must be considered for the predicting of stability limit in the high speed milling.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Chatter Stability Prediction in High Speed Milling Considering Multi-Degree of Freedom

    S.S. SunW.X. TangX.Q. Xu
    p.373-376页
    查看更多>>摘要：Chatter problems occurring during high speed milling affect the quality of the finished workpiece and, to a lesser extent, the tool life and the spindle life. Therefore, the prediction of stable milling regions is a critical requirement for high speed milling operations. In this paper, a dynamic model of a high speed spindle system considering the multi-mode dynamics is elaborated for the purposed of stability prediction. A stability lobes diagram (SLD) shows the boundary between chatter-free machining operations and unstable processes, in terms of axial depth of cut as a function of spindle speed. These diagrams are used to select chatter-free combinations of machining parameters. The proposed method enables a new stability lobes diagram to be established that takes into account the effect of spindle speed on multi-mode dynamic behavior.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    A KNOWLEDGE MANAGEMENT METHOD BASED ON ONTOLOGY FOR AP1000 NUCLEAR

    LIN LinZHANG YongjianYIN Lu
    p.377-380页
    查看更多>>摘要：A knowledge management method for AP1000 nuclear is proposed. Based on the modularization characteristic of AP1000, the set of AP1000 ontology is created. Because the first nuclear power based on AP1000 is still being developed, the ontology model of AP1000 is hard to construct now. The particle swarm optimization is adopted to extract the relatively independent instance models from the complexity AP1000 instance model, which map into the conception models called basis ontology. In order to implement the comparison between two conceptions, using the idea of the DNA inheritance in a family, a similarity measure model of the conception is developed. By means of the general-special relation between the conceptions, the similarity measure model and the basis ontology, the knowledge retrieval for AP1000 is implemented.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Optimal Cutting Parameters for Precision Machining Process

    Qinghua SongWeixiao TangXing AiYi Wan...
    p.381-384页
    查看更多>>摘要：Semi-discretization method is applied to construct stability chart and performance contour in the parametric space for milling processes. The method creates a mapping of the system responses in a finite dimensional state space. Based on the discipline of that, the smaller the largest absolute value (μ_(max)) of the characteristic multipliers of the mapping is, the faster the system converges to zero, minimization of μ_(max) leads to optimal stable limit. The optimal limits are obtained by using stability chart and performance contours. Additional, a novel analytical method for selection of optimal depth of cut (axial depth of cut) is presented. An example of 2-DOF down-milling model is employed to demonstrate the method. It is shown that the spindle speeds corresponding to the optimal depths of cut locate the left side of the resonant spindle speeds, and the optimal cutting parameters pair (spindle speed and depth of cut) can be used to offer high finishing accuracy in precision machining.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Study on the Friction and Wear Behavior of Grind-hardened Layer

    Jianhua ZhangPeiqi GeLei ZhangYang Yu...
    p.385-388页
    查看更多>>摘要：The grind-hardening technology utilizes the grinding heat to harden the surface of the workpiece. The friction and wear performance of the grind-hardened layer is one of the important parameters. In this paper, the friction and wear performance of the grind-hardened layer was studied by the friction and wear experiment. The wear rate and the friction coefficient of the grind-hardened steel were studied by comparing with conventional hardened steel and non-hardened steel. The surface worn morphology and the collected wear debris of the grind-hardened steel were observed during the experiment. The wear mechanism of the grind-hardened steel was analyzed under different friction conditions.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    A Two-Stage Method for Cell Formation Based on Machine Utility

    Le CaoShuge LiFei Liu
    p.389-392页
    查看更多>>摘要：Cell formation is one of the key issues in cellular manufacturing research. A two-stage cell formation method is proposed. With this approach, parts are first clustered into different groups based on similarity factor; then, machines are assigned to these part groups according to the principle of maximum machine utility. Examples show that the proposed method is feasible in grouping parts and machines into cells so that machine utilization and manufacturing systems efficiency are improved.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Influence of Feed on Spiral Inner Grooves Formation with Ploughing

    Yong TangDong YuanLongsheng LuDaxiang Deng...
    p.393-396页
    查看更多>>摘要：Ploughing technology has been applied in manufacturing micro grooves on the outer surface of copper tube. In order to study the formation of spiral grooves on the inner surface of tube, a FEM model operated on DEFORM is established. Two ploughing processes are simulated. At first, an initial groove is manufactured on the workpiece, and then a nearby groove, which will influence the initial groove's geometry, is manufactured with twelve feeds separately. The groove's geometries, including groove width, inclined angle and fin height, are detected. Geometry comparison between the two grooves show that different feed results in different groove shape. According to the geometry change tendency of grooves, the feed can be divided into three different intervals.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Study on the Coated Tool Disability and the Work-piece Surface Quality in High Speed Cutting

    Jin Xu
    p.397-400页
    查看更多>>摘要：The results of the experimental researches show that the high speed cutting tool is disabled in two modes of gradual wear and rapid breakage as HSC proceeds. Tool breakage occurs in low speed cutting. In process of HSC, the tool disability is the combination of flank face wear, boundary wear and cutting edge slope-plane wear. Under the action of the tool cutting movement, the ridges and furrows and burnthrough speckles and the molten metal daub phenomena come into being on the machined surface. With cutting speed increasing, it is weakened that tool wear has adverse effects on the forming of machined surface, and the workpiece surface quality is improved to a certain extent.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Effect of the Internal Stress of Polished Thick Diamond Film on the Infrared Transmittance at Different Temperature

    Rongfa ChenZhaoxia ShenIianggang DaiXianliang Zhang...
    p.401-404页
    查看更多>>摘要：The optical-grade diamond film was prepared by DC plasma jet CVD method, and a double-sided polishing was made by EDM and mechanical polishing technology. The investigations of the internal stress at different temperature on the infrared transmission were tested in detail. SEM and AFM were used to study the polished surface morphology, surface roughness was 0.12nm and 0.25nm. XRD and Raman were characterized on the diamond films, the results showed a higher intrinsic quality. The internal stress distribution and infrared transmittance were investigated at 25℃ and 100℃ temperature respectively. The infrared transmission mechanism of diamond film was also discussed. The main reason of decreasing of infrared transmittance was the increasing grain collisions, which caused more scattering and absorption of incident light with temperature increasing.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd

    Study on Working Hardening for AISI-1020 and AISI-1045 Steel Fine-blanking with Negative Clearance

    J.H. LiW.F. FanZ.M. Zhang
    p.405-408页
    查看更多>>摘要：This paper carries through pure shearing fine-blanking processing experiment with negative clearance for the AISI-1020、 AISI-1045 steel and the relations curves of the blanking force and the blanking stroke is obtained. The micro hardness of the sheared surface for the blanked work pieces in breadthways and lengthways direction is measured by Vickers-micro hardness instrument (MH-6), thereby the relations curves of punch stroke and the micro-hardness of the blanking work pieces are gained. The relation between work hardening degree and blanking clearance for the negative blanking is obtained too. This paper focuses on formation mechanism of work hardening for the negative blanking and analyzes the work hardening capability of blanked work piece. The work hardening degree is compared to the materials which possess different hardening index. The research shows that the work hardening degree of the blanking work pieces is strengthened evidently by the fine-blanking with negative clearance and the hardening layer of blanking fracture could enhance structure intensity and wear resistance of blanking work piece evidently. Therefore, it could enhance fatigue strength exceedingly and extend the working life of work piece greatly.
      原文链接:
    • NETL
    • NSTL
    • Trans Tech Publications Ltd