Development of a micro punching machine tool for micro lens array on steel mold

Micro lens arrays (MLAs) are widely applied in different areas to fulfill different functions. Ultra-precision diamond cutting technology can generate MLA with sub-micrometer form accuracy and nanometer surface roughness but mostly for nonferrous material. In this paper, a three-axis micro punching machine tool is developed to use diamond tool to produce MLAs on steel mold. The developed micro punching machine realizes high-feed and high-precision motions by a macro-micro composite structure. An on-site measurement system based on machine vision is designed to provide evaluation results for MLAs and compensation data for the PZT. The fabrication methodologies for MLAs are studied under the consideration of the output voltage of PZT, tool path generation, and machining parameters. Experiments are conducted to testify the machine tool and the on-site measurement system by machining of MLAs on mold steel. The experimental results show that the micro punching machine can produce MLAs on hard materials with sub-micrometer form accuracy, and the evaluation results from the on-site measurement are close to those from the white-interference profiler.