雷尼绍测头在西门子828D数控系统中的应用

文章主要介绍了雷尼绍PRIMO测头应用在西门子828D系统数控机床上的联接与调试方法。特别就工件测头机械装配、参数通讯设置、PLC控制编程和信号检测等方面进行了详尽地阐述,最后通过测头标定和测量操作演示了该测头在实际加工中的应用,验证了雷尼绍PRIMO测头应用在西门子828D系统数控机床上的可行性。     

基于对象几何特征的触发检测路径规划

研究一种用于数控机床的零件尺寸检测路径规划方法,检测系统用于对加工对象进行监测反馈.文章提出了一种新的基于对象几何特征的触发检测路径规划方案.经过对象几何特征划分,对零件测量过程的安全距离、探测距离等关键检测路径参数进行计算分析,生成控制G代码文件,并以数控机床作为测量运动驱动机构,其主轴携带触发测头对零件完成测量,最后把检测结果通过串行通讯方式传输到控制计算机,通过FANUC 0i系统实验验证了该方法的有效性和可行性.     

数控机床上测头系统测量程序的开发

测头系统是一种高精度的检测装置,安装在数控机床上可实现刀具测量、基准面找正、工件坐标设定、工件在线检测等功能.在对测头系统的作用、组成、工作原理进行分析的基础上,以在加工中心上自动找正凸圆圆心为例,介绍测头系统测量程序的编制方法,使数控机床的操作变得更加简单、便捷、精确、高效,同时为其他相关程序的编制提供参考.     

基于PC的数控机床全闭环控制系统设计

提出一套能在线监测、实时控制的数控机床全闭环自适应伺服控制系统的解决方案。构建“PC＋自适应控制器”模式,在线检测工件的精度指标或者引起误差的因素,并将检测信号反馈回数控系统,经过数控系统的自动处理,实时调整切削加工参数,从而使所检测的误差因素保持在合理的范围,以提高加工零件的精度。采用适应当前数控机床发展潮流的基于PC机的开放式计算机数控系统,实现了由软件来完成设定的功能,并且大大提高了数控系统的自动化程度和自适应控制能力。     

三维测头在数控加工中的应用

以三维触发式测头为核心的数控机床在线测量系统,能够保证数控机床精度,扩大数控机床功能,改善数控机床性能,提高数控机床效率。用户可以通过编程在加工中进行主动测量。分析了自动测量系统的原理,研究了利用宏程序实现型腔检测、寻找孔的中心、调整磨损补偿的自动测量过程。     

数控测头测量功能宏程序的研究

在线测量系统是在现有加工中心基础上配以测头和计算机,运用数控测头在机床上对工件实现在线检测。测量宏程序是加工中心在线检测的依据,研究利用宏程序实现自动测量的过程,不仅提高了工件的精度,而且降低了劳动强度。     

测量领域的前沿技术

多传感器测量技术 采用多种传感器进行测量和检测已成为一种似乎正在不断加速的发展趋势。在当今的测量中，常用的传感器包括：接触（触发）式测头、在其测尖部位采用色光或邻近效应的测头、摄像视频系统，以及各种类型的激光测头。面世不久的X射线计算机断层扫描（CT）传感器可以对工件进行深层检测。     

虚拟式加工中心在线检测仪的开发

设计一种用于工件在线测量的虚拟式检测仪,从工件CAD图提取测量信息并自动生成检测宏程序,对测量数据分析后给出检测结果.对测头系统误差和评定算法误差进行分析,提出一种通过标定测头有效直径来补偿测头预行程误差的方法.对比验证结果表明,虚拟式在线检测仪能进行较高精度的测量.     

西门子数控机床自动化加工过程测头应用保护改进设计

在德国"工业4.0"和"中国制造2025"的推动下,测头在自动化开发应用领域备受青睐。分析了测头在西门子数控机床自动化加工测量应用中存在的风险。针对测头在测量应用过程无防撞、无防转保护问题,基于测头在西门子数控系统测量应用的实现原理,提出利用数控系统的NC异步调用和PLC逻辑控制的改进策略和解决方法。     

数控加工精度在机检测技术研究现状

通过为数控机床配备零件精度检测用测头以及相应的检测代码,即构成在机检测系统。该技术将加工和检测集成在同一台机床上完成,避免了多次装夹、重复定位误差,可以较好地解决零件精度超差难以修正和辅助时间长等现实问题。主要介绍数控加工精度在机检测技术的国内外研究现状与进展,包括在机检测系统开发应用、测头预行程误差补偿技术和带修正功能的在机检测系统开发等。并指出目前在该领域存在的一些关键问题,急需进一步解决和提升。     

面向自由曲面零件的在线检测技术研究现状

数控机床在线检测系统是集数控机床、测头及计算机等为一体的高度集成化系统.高精度在线检测是实现柔性制造系统连续可靠工作的重要手段,是保证数控机床加工精度和效率的重要措施.在航空、汽车、模具等现代工业生产中出现了越来越多的自由曲面零件,这对测量系统提出了更高的要求,因而对具有自由曲面的零件进行高精度高效率的检测将是当前的一个重要研究方向.本文主要介绍自由曲面零件的在线检测技术在国内外的研究现状与进展,包括检测系统开发、自由曲面零件的接触式测量及路径规划和误差补偿等3部分,指出了目前在该领域存在的有待于进一步解决的关键问题.     

5-Axis adaptive flank milling of flexible thin-walled parts based on the on-machine measurement

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.     

Development and evaluation of an on-machine optical measurement device

Demand for fabricating micro-features such as fine holes, micro-cavity for injection moulding, and micro-pin using both conventional (turning, milling, etc.) and non-conventional edge detection method (EDM), wire cut EDM, etc.) processes is increasing significantly. To successfully achieve micro-machining, development of a miniature machine tool, process technology, and on-machine measurement is essential. However, in such tool-based micro-machining processes, proper tool shape monitoring, precision processing, and dimensional control require significant attention. Since these are tool-based machining processes, tool shape monitoring and control are also important technologies to be established.In this study, an on-machine measuring device was developed based on non-contact optical method to inspect dimensions of the fabricated tools (e.g. electrodes for EDM) as well as the wear of tools used for the respective processes. The developed inspection system uses a laser light source and a photo-electronic device. To minimize errors due to the change of tool measurement position and the Fresnel diffraction of laser light, an edge detection algorithm using a linear discrimination function is proposed in this study. Furthermore, an intensity measuring method was added for specimen with a smaller diameter. The experimental results show that the developed on-machine optical inspection system has the accuracy and stability to effectively monitor the fine dimensions of tools and their wear.     

Application of homogenous transformation matrix to measurement of cam profiles on coordinate measuring machines

A kinematic model is presented to aid the cam profile design task and to determine the NC data required to move an inspection probe to the necessary locations to inspect the surface profile of a spatial cam on a coordinate measuring machine (CMM). The cam profile is designed in accordance with the principles of conjugate surface theory. Homogenous transformation matrices are then employed to derive the CMM ability function matrix and the measuring probe location matrix. The required NC data are obtained by equating the elements in the ability function matrix with the corresponding elements in the probe location matrix in order to solve the CMM link variables. The validity of the proposed approach is verified by carrying out the automatic inspection of a machined cam on a CMM using the NC data computed by the developed algorithm. The methodology presented in this study combines the cam design, machining and inspection activities, and makes possible a flexible and automatic spatial cam design and manufacturing process.     

A multiprocess machine tool for compound micromachining

Compound micromachining is the most promising technology for the production of miniaturized parts and this technology is becoming increasingly more important and popular because of a growing demand for industrial products, with an increased number not only of functions but also of reduced dimensions, higher dimensional accuracy and better surface finish. Compound micromachining processes that combine multiple conventional and non-conventional micromachining processes have the capability to fabricate high aspect ratio microstructures with paramount dimensional accuracy. Such machining should be carried out on the same machine with minimum change of setups. At the same time, on-machine tool fabrication along with on-machine tool and workpiece measurement facilities should also be available for further enhancement of the functionality of the machine and higher productivity. In order to achieve effective implementation of compound micromachining techniques, this research seeks to address four important areas, namely (a) development of a machine tool capable of both conventional micromachining including microturning, micromilling, etc., and non-conventional micromachining including microelectrical discharge machining (micro-EDM), wire-cut electrical discharge machining (WEDM), etc.; (b) process control; (c) process development to achieve the necessary accuracy and quality and (d) on-machine measurement and inspection. An integrated effort into these areas has resulted in successful fabrication of microstructures that are able to meet the miniaturization demands of the industry. This paper presents a few tool-based approaches that integrate micro-EDM, micro-EDG, microturning and microgrinding to produce miniature components on the same machine tool platform in order to demonstrate the capabilities of compound micromachining.     

粒子群算法在等误差直线逼近节点方法中的应用

自由曲线是数控加工中经常遇到的工件外形轮廓曲线,但一般的数控系统只有直线和圆弧插补功能。对于自由曲线的直接数控加工,只能用直线或圆弧去逼近其节点,并进行逼近的走刀加工。等误差直线逼近节点的方法能够使所有逼近线段误差相等,是自由曲线直线逼近节点的有效方法之一。在对等误差直线逼近节点算法的研究中,基于几何运算,提出一种新的等误差直线逼近节点的计算方法。该方法通过建立自由曲线的数学模型,运用粒子群算法迭代求取自由曲线上的刀位点坐标信息,并通过VC++编程,实现自由曲线等误差直线逼近数控系统的开发,并验证了该算法的有效性。     

集成化数控工艺过程设计

本文从集成的角度并结合飞机机加工结构件数控加工ＣＡＰＰ系统ＦＡ－ＣＡＰＰ的集成化数控工艺设计技术，对ＣＡＤ／ＣＡＰＰ／ＣＡＭ的集成，数据库和网络的支持，数控工艺决策专家系统等关键技术问题进行了研究与探讨。     

Design of a six-axis high precision machine tool and its application in machining aspherical optical mirrors

The paper presents the design of a six-axis machining system and its application in fabricating large off-axis aspherical mirrors with sub-aperture lapping techniques. The new system is based on computer-controlled optical surfacing (CCOS), which combines the faculties of grinding, polishing, and on-machine profile measuring, has the features of conventional loose abrasive machining with the characteristics of a tool having multiple degrees of freedom moving in planar model. And a novel dual touch-trigger probe profiler is designed, which is composed of a probe, model METRO-MT60 made by HEIDENHAIN Co., is integrated into the system for measuring the shape accuracy of the tested aspherical surface, another probe modeled METRO-MT12 is designed as a calibrating device for minimizing the cosine error caused by assembly inaccuracy. The new CNC machining system with two kinds of moving coordinate systems, dual tool activities and on-machine measuring is presently developed based on the new concept. The general material removal function during machining is analyzed on the basis of the Preston hypothesis. Further, an alignment test of the measuring profiler is carried out using a leveling rule as a specimen. The accuracy of the optical surfaces measured by the dual probe profiler is found to be within 1 μm PV after removing cosine error and error compensating, achieves to the resolving power of the profiler is about 0.2–0.5 μm, so the developed system can be applied to the shape accuracy measuring of aspheric fabrication with micro precision during fine grinding process according to the calibrating results. Finally, the manufacturing experiments are carried out by virtue of an off-axis oblate ellipsoid mirror with rectangular aperture as 770 mm×210 mm and centered 127 mm. The accuracy of the aspherical mirror improved from the initial form error of 17.648 μm rms to the final one of 0.728 μm rms after grinding for 200 h.     

ARX技术在数控加工中的应用

文章首先基于ARX技术的特点分析了该技术在数控加工中应用的可行性，然后结合MFC技术实现了基于Aut0CAD平台的NC代码查询、加工工艺干预、NC代码的自动编程、NC代码的验证以及加工过程的动态仿真与在线检测等功能，从而使数控加工更精确、更高效，同时也为实现数控加工的CAD／CAM／CIMS一体化提供了一种可行的途径。