Profile error compensation in high precision 3D micro-EDM milling

Together with the product miniaturization trend, manufacturing technologies to fabricate small size shapes are highly demanded for micro-mold and die industry. Among the versatile machining processes, micro-EDM milling is superior owing to its negligible cutting force. By using layer by layer removal strategy in association with CAM software for tool path generation, intricate 3D micro-shapes could be produced. However, there exist some systematic errors which affect the dimensional accuracy and the final form of obtained shapes. This study attempts to identify and analyze the error components of 3D micro-EDM milling process. It is found that aside from the inherent machining gap and the indispensible electrode wear, the corner radius of virtual electrode is also of prime importance in determining the machining accuracy. In this study, geometric models are presented to simulate its effects. It is detected that the profile error could be reduced by implementing the corner radius into virtual electrode model. For verification, typical 3D micro-shapes formed by the inclined planes and a partial sphere are fabricated with and without the new model for virtual electrode geometry.