微细电火花加工的微细电极在线检测

设计了微细电极在线检测系统。系统由卤素灯光源、变焦显微镜头、CCD摄像机和6自由度支架组成,具有1.61 μm的分辨率和113~729的放大率。在Linux平台下,基于V4L2 API开发了图像采集程序,使用mmap()内存映射方法获取图像数据。实现了IplImage数据结构和QImage类的转换,使图像既可以基于OpenCV进行处理,又可以基于Qt进行显示,通过Canny边缘检测算法提取了微细电极的边缘轮廓。实现了电极在线观测的G代码功能,进行了块状电极电火花磨削微细轴的实验。实验结果表明系统可以在线观察电极状态和在线测量电极尺寸,在线测量值与扫描电镜离线测量值的相对误差在5%以内, 解决了微细电火花加工的微细电极在线制造和检测等难题。

Micro electrodes on-line measurement in micro EDM

An on-line measurement system was proposed. It is composed of a halogen type light source, a zoom lens, a CCD camera and a bracket that has 6-degree of freedom. It has a resolution of 1.61 μm and a magnification of 113~729. Based on the Linux operating system, an image capturing program was developed with the V4L2 API, in which the image data was acquired with the method of mmap() memory map. The conversion between the data structure of IplImage and the class of QImage was implemented. Therefore the image could be processed by using OpenCV, as well as showed with Qt. The contour of micro electrodes can be extracted by means of the Canny edge detector. Furthermore, the G code for on-line measurement was also developed. The experiment of block electrodes Electrical Discharge Machining (EDM) grinding was carried out. It shows that the relative error between the on-line measurement system (OMS) and the scanning electron microscope (SEM) is less than 5%. It also shows that the system can be used to deal with the difficulties in micro electrodes on-line fabrication and measurement in micro EMD.