Development of vision guided diamond turning tools automatic lapping system

With the development of ultra-precision machining technology for aspheric surface and optical free-form surface, the demands of high-precision circular arc monocrystal diamond turning tools are increasing. At present, most diamond turning tools are manufactured by skilled workers, so the market demands for precision and efficiency are difficult to be satisfied. In this research, an vision guided diamond turning tools automatic lapping system was developed. Using shape-based template matching method to improve the tool' initial installing precison, and then profile information of cutting edge in sub-pixel precision was obtained by image processing technologies. High precision diamond cutting edge can be achieved under pertinent lapping. This method can avoid the error which is inevitably caused by refixturing process for off line measurement in the traditional lapping process, and reduce the influence of human factors in lapping results. In cutting edge truing experiments, diamond tools with radius 1 mm, 0.5 mm and 0.2 mm were measured sucessfully by image processing method. It could acquire the profile information needed by automatic lapping online, and provide a guarantee for development of automatic lapping system in accuracy and efficiency. Cutting edge of profile tolerance ≤ ± 1µm was finished in experiments.