磨料加工的最新进展

市场状况 据美国《磨料磨具产品与市场》报告预测,到2004年,整个磨料磨具产品的需求总量将达到58亿美元,年均增长4％。航天和电子产品市场的增长将带动制造业对磨料磨具的需求,保守的估计也将会达到年均增长3.8％。其中,磨料将占有最大的销售份额,之后是粘结磨具。随着产品的进步,使用寿命不断增长,需求量将受     

平面齿轮齿形加工

一、平面齿轮的制造平面齿轮齿形制造通常有两种方法 :展成切削和模具成形。对于展成切削 ,笔者是在普通插齿机上加工一对锥齿轮 ,使工件轴线与插齿刀轴线垂直相交 ,模拟工作状态进行加工。图 1所示为改装插齿机传动系统图。插齿刀作往复直线及连续旋转运动 ,以实现切削和展成 ,工件则作定传动比的旋转运动 ,且可以相对移动 ,以实现进给加工到要求的深度。若刀具与相应齿轮的几何参数相同 ,则可加工相配的平面齿轮。一般刀具用高速钢及硬质合金材料制造 ,可以加工非淬火的钢制工件。工件加工后若还要提高精度可采用剃或研磨加工。对于模具成…     

磨粒固化气囊光整技术及试验研究

针对模具激光强化表面高硬度、高耐磨性以及局域硬度差异等问题,提出了一种磨粒固化气囊光整加工新技术,以期实现模具激光强化表面的高效精密自动化光整加工.该技术将处于游离态的磨粒通过高分子粘结剂固化于橡胶基体表层,使磨粒群获得更稳定的支撑,形成了更有效和平稳的切削效果.根据磨粒固化气囊的性能要求,从材料特性着手,确定出通过酸性硅酮密封胶将磨粒直接固化在丁苯橡胶基体表面,以制得磨粒固化气囊的工艺方法;借助机器人辅助加工平台,对制得的不同粘结层厚度的磨粒固化气囊进行了光整试验研究.研究结果表明:通过控制磨粒固化气囊的均匀性,加强复合层的粘结效果,可以降低工件表面粗糙度,提高加工效率,为模具高效光整加工奠定了坚实的基础.     

Abrasive waterjet machining simulation by SPH method

Abrasive waterjet machining (AWJM) is a non-conventional process. The mechanism of material removing in AWJM for ductile materials and existing erosion models are reviewed in this paper. To overcome the difficulties of fluid–solid interaction and extra-large deformation problem using finite element method (FEM), the SPH-coupled FEM modeling for abrasive waterjet machining simulation is presented, in which the abrasive waterjet is modeled by SPH particles and the target material is modeled by FE. The two parts interact through contact algorithm. The creativity of this model is multi-materials SPH particles, which contain abrasive and water and mix together uniformly. To build the model, a randomized algorithm is proposed. The material model for the abrasive is first presented. Utilizing this model, abrasive waterjet penetrating the target materials with high velocity is simulated and the mechanism of erosion is depicted. The relationship between the depth of penetration and jet parameters, including water pressure and traverse speed, etc., are analyzed based on the simulation. The results agree with the experimental data well. It will be a benefit to understand the abrasive waterjet cutting mechanism and optimize the operating parameters.     

Further investigation into extrusion of trocoidal gear sections considering three-dimensional plastic flow

In the present study, theoretical development proposed in previous work carried out in extrusion of clover sections in relation to a generalized die design method is presented in the extended scope for three-dimensional extrusion of trocoidal gear sections from round billets with experimental verification. Computations are carried out for clover and trocoidal gear sections. The CAD/CAM of the suggested dies is introduced for the experiments. Experiments are carried out for a clover section and a trocoidal gear section with eight teeth. Al 2024 aluminum billets were used as the working material. Half-cut specimens are used for flow visualization of the extrusion process. The theoretical predictions are in good agreement with the experimental results in extrusion load and metal flow.     

数字齿轮加工的基本运动

提出数字齿轮加工的两种基本运动同步运动和插补运动。适应这两种运动所需要的控制系统都是位置控制系统。利用这两种运动进行综合可以加工出各种各样的齿轮。     

Abrasive tools for hole machining in robotic systems

The operation of a single abrasive grain in internal grinding by a composite abrasive wheel is considered. In particular, the transition from deformation to microcutting is analyzed on the basis of the Kragel’skii criterion.     

Effect of machining characteristics on polishing ceramic blocks

In this study, experiments were conducted to examine the effects of polishing parameters such as polishing time, load, rotational speed, diamond size, and concentration when polishing ceramic blocks. It was shown that the material removal rate rises with the increase in polishing time from 20 to 30 min, but drops with the increase from 30 to 40 min. The material removal rate increases with an increase in the load, rotational speed, diamond size, and concentration, respectively. Within the range examined, the surface roughness improves with a longer polishing time, higher rotational speed, smaller diamond size, and lower concentration. The parallelism is highly dependent on the material removal rate. Three main failure mechanisms: cracks, deep pits, and fractures were observed.     

提高齿轮加工质量的几种方法

介绍齿轮在加工过程中提高加工质量的几种方法,正确的使用这些方法加工齿轮可以有效的提高齿轮的加工精度,降低制造成本。     

齿轮啮合侧隙对数控插齿机加工精度的影响

根据数控电子导套插齿机的结构特点,从齿轮侧隙对插削加工斜齿轮精度的影响角度出发,利用虚拟样机技术对插削过程中齿轮侧隙的变化情况进行分析,提出转速变化影响侧隙位置的概念,并详细阐述了当插齿机转速变化时齿轮侧隙与加工精度的关系。     

斜齿锥齿轮产型轮的数控加工

介绍了利用UG生成斜齿锥齿轮产型轮的刀具轨迹进而获得数控代码,并在此基础上由4轴联动加工中心完成其齿廓加工的基本思想和具体步骤。为该类齿轮的数字化加工提供了有益的参考。     

电火花加工内齿轮

介绍电火花加工内齿轮及其工艺,并对其中的技术难题和关键技术进行了分析.用此方法加工成本低,效率高,操作方便,产品质量稳定.     

齿轮虚拟加工仿真系统研究

应用Visual Basic6.0可视化语言编程形象地模拟出齿轮加工时的动态过程.介绍虚拟加工系统的模块结构和功能,阐述应用VB开发运行于Windows操作系统下的齿轮加工过程仿真系统的关键技术和方法.利用该系统能够在较短的时间内显示出不同参数的标准渐开线齿轮和变位齿轮齿廓的范成过程和齿形的变化,以及其三维实体参数化模型.本系统不仅克服了利用齿轮范成仪做实验时参数不能改变的局限性,而且为齿轮三维参数化造型设计和数控加工提供一种实用、有效的方法.     

变直径弧面分度凸轮的加工

从凸轮与滚子在空间的啮合关系入手,分析了变直径刀具加工弧面分度凸轮的运动关系,确定了采用刀位补偿原理加工变直径弧面分度凸轮基本思路,推导了变直径刀具的补偿方向和补偿量的计算公式,最后利用CAXA和CAMAND等软件的后处理功能,实现了刀位验证.     

锥齿轮齿形加工的第二次革命

一种新型锥齿轮铣床和磨床为未来的机床制造业树立了一个典范。刀具头架回转而不是工件齿轮回转的单立柱方案为锥齿轮制造者开辟了一个可能获利的新天地，新方案的优点是占地面积小、经济性好，最佳的排屑和卓越的铣削结果。     

摆线齿轮计算及数控加工

着重介绍了内外摆线齿轮齿形坐标计算方法,并利用CAXA数控铣软件编制加工中心程序。     

普通铣床加工椭圆柱齿轮

根据椭圆曲线形成原理,在椭圆柱轮廓上分段计算出齿轮参数,找出了其内在变化规律,利用这些规律在普通铣床上加工椭圆柱齿轮。     

滚削大质数螺旋齿轮机床挂轮的优化选择

滚削大质数螺旋齿轮必须使用分齿、进给、差动三组挂轮。由于实际挂轮的传动比与理论值之差异,会造成被加工齿轮的误差。笔者推荐一种改进的方法,可消除分齿挂轮及进给挂轮带来的误差,最终造成齿轮误差的仅有差动挂轮,这样可大幅提高被加工齿轮的精度。