在Y7125磨齿机上磨削齿轮刀具的砂轮修形轨迹计算

根据Y7125磨齿机的磨齿原理和齿轮啮合原理,建立了磨削齿轮刀具的数学模型,基于齿轮坐标系中的齿形方程,得到砂轮坐标系中的截形方程,据此确定了精确磨削修形齿轮刀具的砂轮截形曲线,并给出了解析实例。     

双端面磨削中砂轮修整形貌的几何学分析

针对双端面磨削中高精度与高效率难以同时实现的问题,以上砂轮磨削面形貌为研究对象,建立了修整后的上砂轮磨削面坐标方程,分析了工件磨除量在磨削区内的分布。分别建立了下砂轮坐标系、修整坐标系和上砂轮坐标系,通过空间几何坐标变换和MATLAB软件仿真,绘制了上砂轮磨削面的Z向坐标沿砂轮半径方向的变化曲线、上砂轮磨削面内任意点到下砂轮磨削面的距离随工件转角的变化曲线,分析了上砂轮磨削面的不同形貌对双端面磨削加工精度及精度保持性的影响。实验结果与计算分析吻合,验证了计算分析的正确性。     

F-Theta自由曲面透镜的精密与镜面磨削

针对光学玻璃的F-Theta自由曲面透镜加工困难等问题,提出将金刚石砂轮的椭圆环面代替圆环面,进行F-Theta自由曲面磨削加工,研究形状误差的补偿磨削方法和光学玻璃的镜面磨削工艺。根据F-Theta透镜的自由曲面建立砂轮与工件相切的刀具轨迹法向算法。采用#46粗金刚石砂轮修整成椭圆环面,提出自由曲面磨削的法向误差补偿加工模式。最后,采用#3000超细金刚石砂轮的椭圆环面进行轴向磨削试验。试验结果表明:传统的垂直误差补偿磨削可减小面形误差45.9%及其PV值11.6%;而新提出的法向误差补偿磨削可减小面形误差47.9%及其PV值41.5%。此外,超细砂轮磨削可使得自由曲面的粗糙度达到28 nm,其镜面磨削工艺有别于较粗砂轮磨削工艺。因此,椭圆环面砂轮的法向补偿磨削是提高自由曲面加工精度的有效方法,而且,无需研磨抛光就可以实现光学玻璃的自由曲面镜面磨削。     

基于视觉的毛坯件磨削路径规划方法

以某型号刹车片支架为研究对象,对不规则曲线磨削路径规划进行了研究,提出了一种基于视觉的毛坯件磨削路径规划方法。分别对刹车片支架的毛坯件与标准工件图像进行图像处理,将等参数步长法与等弦高误差法相结合,对毛坯件与标准工件的一条边缘进行离散,且将得到的图像坐标系下的离散点变换至世界坐标系下。对世界坐标系下的离散点进行三次样条插值与拟合,通过对比确定毛刺部分,进而判断毛刺高度,确定磨削路径。所提出的基于视觉的毛坯件磨削路径规划方法为毛刺判别与不规则路径规划提供了解决方案,并为进一步实现机器人自动化磨削提供了技术支持。     

磨削油在硬质合金刀具高质量磨削过程中的应用研究

为研究磨削油对硬质合金刀具高质量磨削的影响,通过对两种不同磨削油的清洗性、渗透性及冷却性等基本性能进行测试,分析磨削硬质合金刀具时对机床负载、砂轮工作表面、硬质合金刀具磨削表面质量以及磨削温度的影响规律。试验结果表明：砂轮表面形貌变化、砂轮磨耗磨损和机床负载主要受磨削油清洗性能的影响,磨削油的清洗性能越好,WC在砂轮工作表面黏附越少,砂轮表面形貌变化、砂轮磨耗磨损和机床负载越小;硬质合金刀具圆周刃崩边大小及前刀面粗糙度主要受磨削油渗透性能的影响,其渗透性能越好,磨削区越易形成油膜,圆周刃崩边大小及前刀面粗糙度值越小;磨削区温度主要受磨削油冷却性能的影响,其冷却性能越好,带走的磨削热越多,磨削区温度越低。     

圆锥球头立铣刀的CNC磨削模型及工艺

复杂形状刀具结构上的复杂性导致了磨削加工的复杂性。利用圆锥球头立铣刀这一典型复杂形状刀具,对其圆锥部分和球头部分的刀刃曲线的连续性进行了分析,然后对刀刃结构和加工特性进行研究,再利用Frenet标架来确定砂轮的摆放姿态,实现利用活动坐标系控制机床坐标的插补进给,并通过磨削实例验证。     

一种粗铣刀周齿分屑槽的数控磨削工艺算法

针对粗铣刀分屑槽形状的磨削工艺，对粗铣刀周齿分屑槽结构参数进行了定义，建立了加工坐标系及切深引导曲线方程；借助运动学理论，提出了砂轮磨削姿态和砂轮磨削轨迹的计算方法；在VC++环境开发了一套算法模块，并对其进行了仿真验证及与Numroto磨削软件的仿真结果对比。结果表明，该轨迹算法能够较好的实现预期效果，具有较好的刀具结构扩展性和加工精度。     

硬质合金磨削裂纹的产生与预防

对于硬质合金刀具在磨削过程中采用碳化硅砂轮磨削产生裂纹的原因进行了阐述,目的是为了以后在硬质合金刀具加工中减少裂纹.同时由于硬质合金刀具用途广泛,能够减少磨削裂纹的产生,可以提高硬质合金刀具的刃磨水平.     

硬质合金刀具的电解磨削

硬质合金刀具在金属切削加工上日益广泛地被应用,对如何提高硬质合金刀具的刃磨质量,不断提高生产率和零件加工质量,已成为迫切需要解决的问题。目前各厂采用碳化硅或金刚石砂轮进行硬质合金刀具的粗、精磨削,砂轮损耗大,刃磨工序繁,磨削时产生热,容易使刀片出现裂纹、烧伤、崩刃等现象,且刃磨质量差,效率较低。金刚石砂轮磨削时虽能获得较高的表面质量,但砂轮价格贵,有一定的局限性。硬质合金刀具的电解磨削是克服机械磨削缺点,稳定获得▽▽▽▽10以上光洁度的一种有效加工方法。现介绍如下。     

金刚石砂轮加工整体硬质合金刀具的磨削参数选择

磨削参数会影响磨削质量、砂轮的使用寿命以及加工效率,本文阐述了磨削整体硬质合金刀具所用的砂轮类型,列举了在磨削中常见的问题并分析了问题产生的原因及在磨削参数方面应采取的措施。介绍了一种快速确定合适的磨削参数的方法,该方法用于将磨削参数经验数据扩展至新规格刀具的加工中。     

五轴工具磨床通用后置处理研究

数控机床后置处理能将刀位轨迹转换为机床数控加工程序,其先进程度对零件加工质量和效率有重要影响。目前五轴工具磨床后置处理大都专机专用或另外购买专用后置处理模块。通过对五轴工具磨床的结构类型分析,建立通用五轴工具磨床运动模型,并采用机床运动创成函数将砂轮的位姿转换为机床各轴的运动量,从而得到五轴工具磨床通用后置处理方法,提高了五轴工具磨床后置处理算法的通用性。     

新型游动坐标法及其在复杂形状刀具数控磨削中的应用

通过分析复杂形状刀具的几何角度和数控磨削工艺 ,提出一种新型游动坐标系的刀位计算方法 ,应用该方法可简便地进行复杂形状刀具数控磨削的刀位计算 ,并可实现复杂形状刀具几何角度的精确磨削。通过三维仿真及实际磨削加工试验验证了该刀位计算方法的实用性。     

模具二维轮廓铣削加工刀具轨迹的仿真模型

开发了模具二维轮廓铣削加工刀具轨迹生成系统,此系统在模具加工车间使用,按实际使用的刀具半径进行编程,直接在机床外部计算出无干涉的加工轨迹,加工时不用引入刀具半径补偿,避免了加工干涉。系统还具有直观、简单的图形用户界面及刀具轨迹可视化功能,在模具的生产制造中有着一定的实用价值,而且对于其它类型工件二维轮廓加工也同样适用。     

Development of an analysis system for geometric contour error evaluation in ultra-precision machining for microlens arrays

A basic principle for acquiring precisely shaped machined parts is to create dense tool path data. However, as the density of tool paths increases, the volume of data increases. The significant increase in data consumes more memory and machining time. Therefore, the creation of tool path data of unlimited density is impractical. This paper proposes a contour error evaluation system. The system makes correct decisions based on the expected quality of a workpiece. Specifically, the user creates tool path data by calculating deviations in the contour in relation to variations in the intervals of the tool path. The user can create tool paths by adjusting the amount of tool path data within the desired quality level. Accordingly, before the start of the machining process, the user can predict any machining loss likely to result from the excessive amount of data created in the creation phase. In addition, the tool path data of the proposed system are experimentally compared with the actual shape of a part machined with a microlens array machining system.     

塑料注塑的CAD／CAE／CAM（Ⅴ）注塑模计算机辅助制造

给出了一个加工复杂注塑模的ＣＡＭ系统，包括从毛坯到合乎设计要求的模具成品的加工过程的多个环节，主要对加工的刀具轨迹的自动生成及干涉检查、曲面检测轨迹的自动生成及干涉检查、精加工的刀具轨迹的自动生成作了详细介绍。     

A manufacturing model of helical groove on rotary burr and a universal post processing method

A systematic machining theory and precision method to determine cutter location in a grinding system is presented for rotary burr. First, the helical cutting edge on various kinds of revolving surfaces is built. Then, based on the geometry model of the helical cutting edge, the smooth spiral rake surface with constant normal rake angle and flank surface can been formed during the one-pass grinding process by this method. No interference between the grinding wheel and workpiece happens by the wheel special rotation. The method has the characteristic of detaching the grinding wheel path solution from specified machining conditions. The grinding wheel path is suitable for different NC machine tools through post processing. Meanwhile, a mechanism kinematic model of the NC machine tool is built, and a generalized algorithm for post-processing of multi-axis NC machine tools is presented. This model is applied to arbitrary configuration of NC machine tool, and the motion value for each axis will be generated by the inputting structure and motion parameters of the machine tool. The model, together with the machining method mentioned in this paper, make the calculation and generation of the grinding wheel path simpler and universal. At last, the validity of the method given in the paper is identified by an example of grinding.     

Capturing the tacit knowledge of the skilled operator to program tool paths and tool orientations for robot belt grinding

This paper describes a novel methodology for generating grinding tool paths, orientations and grinding parameters based on the captured trajectories of a surface finishing tool operated by the skilled operator. First, a variable frame size moving window principal component analysis is performed on the trajectories. Next, features such as the amplitude, speed of the tool centre point, direction of travel, average position, contact force and orientation of the grinder are calculated. Kernel k-means clustering is applied to the trajectory’s feature vectors for segmentation into the tool path primitives. The robotic tool path primitives would be ordered similar to the manual tool path primitives in the grinding strategy. The robotic tool path primitives are then generated based on the boundaries of the manual tool path primitive in a computer-aided manufacturing software. Anchor points are selected from the corners and at intermediate sections along the robotic tool path to inherit the orientations of the manual tool path. Using the inherited skilled operator tool orientations, spherical linear interpolation and spherical spline quaternion interpolation are used to interpolate the orientations for the robotic tool path points along the cross curves, followed by the flow curves, respectively. A finite element model of the belt grinding process is also introduced to quantify the effect of the contact wheel serrations on the material removal rate. This is to account for the difference in contact wheel design between the handheld and robotic grinding tool. The programmed robotic tool paths generated from the trajectories captured from a skilled operator were proven to be able to grind the workpiece to the desired profile within the desired tolerance in a pre-production environment.     

叶片复杂曲面的机器人抛磨工艺规划

为了实现复杂曲面工件的智能抛磨加工,对叶片复杂曲面进行机器人抛磨工艺规划。对抛磨点位置规划算法和基于最大接触原则的抛磨姿态规划算法进行了研究。首先,通过平行截面法获得抛磨路径割线,以非均匀有理B样条(NURBS)曲线描述。接着,提取曲线特征参数,根据设定的阈值进行抛磨点规划,再基于抛磨轮与工件的最大接触原则进行抛磨点姿态规划,从而得到完整的抛磨路径。然后,将工件位姿从工件坐标系转换到TCP坐标系。最后,搭建了柔性抛磨系统仿真平台生成机器人控制程序。实验结果表明,此方法规划的路径可用于叶片复杂曲面的机器人抛磨加工。分别用本文规划所得路径和CAM软件规划所得路径对叶片进行抛磨加工,测得表面粗糙度分别为0.695~0.930μm和2.803~3.243μm。本文提出的抛磨位姿规划方法可用于复杂曲面工件的抛磨路径规划,使工具和工件保持最大接触,从而避免了位姿不合理所产生的过抛和欠抛。     

用于复杂空间曲面加工的机器人磨削系统

开发的用于复杂曲面的磨削机器人磨削系统由六自由度ABB机器人和砂带磨削机组成,其工艺流程包括工具和工件位姿标定、加工路径离线编程、自动磨削加工和检测。弹簧、比例阀构成的力补偿系统保证了磨削过程中接触力的稳定。该系统加工出的汽轮机叶片形面误差和表面质量比传统方法加工出的叶片有大幅度提高。     

非球面平行法磨削技术研究

文中针对硬脆材料非球面光学元件平行法磨削技术进行了研究,从加工原理上分析了平行法磨削技术不同于传统非球面磨削技术的特点,并通过几何关系建立了两轴联动非球面平行法磨削加工时球头砂轮运动模型,为非球面平行法磨削加工系统结构设计和数控系统轨迹计算奠定了基础.