共查询到19条相似文献,搜索用时 156 毫秒
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针对现有带锯的锯切负载模型误差较大且无法预测动态特性等问题,将锯切负载特性分为稳态特性和动态特性进行研究。引入锯齿的锯削与刮削并存原理和斜锯齿等效原理,提出等齿距工况下单个锯齿的锯切负载稳态特性模型;引入锯切进给过程的微位移等效原理,优化锯切负载的锯削部分负载动特性;引入套齿周期特性和锯带传动的周期特性,建立了变齿距工况下单锯齿锯切负载的动特性模型。结果表明,单齿、套齿以及锯带传动的周期特性与实验结果吻合,并且3个主要锯切负载频率的误差不超过4%,因此,提出的模型可以较好地预测实际锯切负载动态特性。 相似文献
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《工具技术》2017,(11):25-29
采用正交试验方法对钛合金进行切削试验,研究了切削用量和刀具前角对切削力和锯齿化程度的影响规律,并采用金相显微镜对锯齿形切屑的切屑形貌和绝热剪切带内材料特征进行观察和分析。结果表明:进给量和背吃刀量对切削力的影响高度显著,刀具前角对进给力的影响高度显著而对主切削力的影响显著;刀具前角、进给量、切削速度对锯齿化程度的影响显著性依次减小;随着锯齿形切屑变形程度增加,绝热剪切带内组织特征由形变带向转变带转化;锯齿形切屑裂纹形成于绝热剪切带与下一个梯形基块的交界处,并沿绝热剪切带方向扩展;刀具前角对裂纹影响较显著,当刀具前角为10°时,裂纹更加明显。 相似文献
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根据弧齿锥齿轮轮坯、刀盘及机床调整参数,建立了弧齿锥齿轮的三维加工模型。研究了金属切削加工有限元分析中所涉及的刀屑界面摩擦模型、刀屑接触定义、切屑分离准则等相关关键技术。建立了弧齿锥齿轮铣齿加工过程的有限元模型,通过ABAQUS软件仿真模拟出了不同工艺参数和刀具参数下的铣齿加工过程,得到了切削层形态及应力分布结果。研究结果表明:刀具前角增大,切削层变形减小,主切削力减小;切削速度增大,主切削力减小;刀具的合理前角应取为20°,切削速度应根据实际情况取较大值。同时也为选取和研究弧齿锥齿轮加工工艺参数提供了一套有效的方法。 相似文献
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<正>在生产加工过程中为使带锯条与被锯工件保留一定间隙而使锯齿交替分布于锯带左右两侧,锯条在切削过程中形成切削间隙,锯齿向锯带侧面的凸出量,即分齿量。分齿量的大小和偏差在标准中有明确要求,且分齿量的分布情况对锯条切削寿命和锯切金属表面的质量关系很大,因此在生产过程中必须严格检验和控制。工艺要求在分齿加工过程 相似文献
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刀具几何参数对钛合金铣削力和表面完整性的影响 总被引:1,自引:0,他引:1
针对TC18钛合金铣削过程,采用正交试验研究了硬质合金刀具几何参数对铣削力和表面完整性的影响,建立了铣削力经验模型,并分析了铣削力对刀具前角、后角和螺旋角的绝对灵敏度和相对灵敏度;采用田口法分析了刀具几何参数对表面粗糙度和表面残余应力的影响。结果表明:大前角、小后角、大螺旋角的条件下铣削力较小,铣削力对刀具螺旋角的变化最敏感,对后角次之,对前角最不敏感;铣削表面均为残余压应力,刀具螺旋角对表面粗糙度的影响显著,刀具后角对表面残余应力的影响显著。 相似文献
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采用ANSYS有限元分析软件,建立了螺旋齿拉刀一个刀齿的有限元模型,通过加载求解,得到拉刀刀齿工作时受力后的位移和应力分布情况。利用正交实验分析方法,对拉刀的前角、后角、刃倾角、齿距等参数进行了分析和优化,为改进拉刀受力情况、合理设计拉刀结构以及对拉刀进行失效分析提供了理论依据。 相似文献
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任意齿差纯滚动活齿传动齿形设计方法及啮合特性研究 总被引:3,自引:0,他引:3
由于高次多项式类曲线具有无刚、柔性冲击的特点,为实现任意齿差纯滚动活齿传动,提出基于五次多项式类曲线的新齿形设计方法。基于转速变换和包络原理,推导出中心轮齿廓方程,制定中心轮避免齿形干涉的设计条件,分析中心轮齿形曲率半径变化规律,阐释活齿轴半径对中心轮齿形的影响;根据活齿传动啮合原理,以压力角表达式表征啮合特性,并对影响最小压力角及传力齿廓区间大小的表征参数进行分析,为任意齿差纯滚动活齿传动结构几何参数的选择提供了设计依据。给出设计实例,验证理论分析结果的有效性,仿真结果表明,高次多项式类任意齿差纯滚动活齿传动受力效果好,传动平稳,设计方法简单,易于形成模块化与系列化设计,具有广阔的应用前景。 相似文献
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Shuangxi Xie 《The International Journal of Advanced Manufacturing Technology》2013,67(9-12):2619-2626
Accurate tooth surface and good surface quality are critical to achieve the low-noise bevel gear drives. Face milling, traditionally works as tooth roughing process, can now possibly be used for finishing process because its high speed can produce good tooth surface quality. But with the previous simplified cutter geometric model in tooth modeling, the high accurate tooth surface cannot be obtained. In this paper, a genuine face milling cutter geometric model for spiral bevel and hypoid gears is proposed. This model exactly matches with the cutter geometry in the industrial application when not considering the fabrication tolerances and tool wear . In the modeling, the blades of the genuine cutter are parameterized with blade angle, rake angles, and relief angles. The side and circular cutting edges of blades are represented on the blade rake plane, rather than the normal plane as the simplified cutter geometry. The mathematic model of the genuine tool profiles on the normal plane is derived. It can be conveniently used by the existing tooth modeling program and easily customized by specifying the geometric parameters. In comparison with the genuine tool profile with the simplified tool profile, the big geometric errors of the simplified blade profile are founded, which proves that the genuine cutter geometric model is correct and essential. 相似文献
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Chunhui Ji Jing Shi Yachao Wang Zhanqiang Liu 《The International Journal of Advanced Manufacturing Technology》2013,68(1-4):365-374
The interaction between the tool rake face and the chip is critical to chip morphology, cutting forces, surface quality, and other phenomena in machining. A large body of existing literature on nanometric machining or nano-scratching only considers the overall friction behavior by simply regarding the total force along tool movement direction as the friction force, which is not suitable for describing the intriguing friction phenomena along the tool/chip interface. In this study, the molecular dynamic (MD) simulation is used to model the nanometric machining process of single crystal copper with diamond tools. The effects of three factors, namely, tool rake angle, depth of cut, and tool travel distance, are considered. The simulation results reveal that the normal force and friction force distributions along tool/chip interface for all cases investigated are similarly shaped. It is found that the normal force consistently increases along the entire tool/chip interface when a more negative rake angle tool is used. However, the friction force increases as the rake angle becomes more negative only in the contact area close to the tool tip, and it reverses the trend in the middle of tool/chip interface. Meanwhile, the increase of depth of cut overall increases the normal force along the tool/chip interface, but the friction force does not necessarily increase. Also, the progress of tool into the work material does not change the patterns of normal force, friction force, or friction coefficient distributions to a great extent. More importantly, it is discovered that the traditional sliding model with a constant friction coefficient can be used to approximate the later section of friction distributions. However, no friction model for traditional machining is appropriate to describe the first section of friction distributions obtained from the MD simulation. 相似文献
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高速车削镍基高温合金GH4169的切削力仿真研究 总被引:1,自引:0,他引:1
基于Deform 3D仿真软件建立了GH4169高温合金高速车削的有限元模型,采用四因素三水平正交试验方法研究了切削用量和刀具几何参数对切削力的影响规律,并建立了切削力经验公式。研究结果表明:在高速车削GH4169的过程中,对切削力影响最大的参数是切削深度,其次是进给量和前角,最后是刀尖圆弧半径;切削力随切削深度和进给量的增大而增大,随前角的增大呈现先降低又升高的趋势,而刀尖圆弧半径增大时切削力变化不大;最佳参数组合为:进给量0.2mm/r,切削深度0.4mm,前角10°,刀尖圆弧半径0.2mm。 相似文献
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M. A. H. Mithu G. Fantoni J. Ciampi 《The International Journal of Advanced Manufacturing Technology》2011,55(9-12):969-982
The bandsawing as a multi-point cutting operation is the preferred method for cutting off raw materials in industry. Although cutting off with bandsaw is very old process, research efforts are very limited compared to the other cutting process. Appropriate online tool condition monitoring system is essential for sophisticated and automated machine tools to achieve better tool management. Tool wear monitoring models using artificial neural network are developed to predict the tool wear during cutting off the raw materials (American Iron and Steel Institute 1020, 1040 and 4140) by bandsaw. Based on a continuous data acquisition of cutting force signals, it is possible to estimate or to classify certain wear parameters by means of neural networks thanks to reasonably quick data-processing capability. The multi-layered feed forward artificial neural network (ANN) system of a 6?×?9?×?1 structure based on cutting forces was trained using error back-propagation training algorithm to estimate tool wear in bandsawing. The data used for the training and checking of the network were derived from the experiments according to the principles of Taguchi design of experiments planned as L 27. The factors considered as input in the experiment were the feed rate, the cutting speed, the engagement length and material hardness. 3D surface plots are generated using ANN model to study the interaction effects of cutting conditions on sawblade. The analysis shows that cutting length, hardness and cutting speed have significant effect on tooth wear, respectively, while feed rate has less effect. In this study, the details of experimentation and ANN application to predict tooth wear have been presented. The system shows that there is close match between the flank wear estimated and measured directly. 相似文献