A robust approach to enhance adaptability of skiving cutter in manufacturing gear injection molds with variable shrinkage rates

Gear mold is typically manufactured through an EDM process employing a gear electrode core. In addition, the gear electrode is commonly machined using a milling or hobbing process. Nevertheless, the milling process generates only a single tooth groove in one machining cycle. Additionally, the hob cutter geometry is redesigned when changing the plastic’s shrinkage rate. Therefore, this study introduces a robust approach to applying the skiving process, focusing on cutter reutilization in manufacturing gear electrodes with different shrinkage rates. First, the cutting edge of the skiving cutter is located on the imaginary gear, where the imaginary gear correctly meshes with the basic rack of the gear electrode at a predefined shrinkage rate. The generating rack of the cutter is generated by predicting and solving the meshing condition with the cutting edge. Accordingly, the cutter body is produced by simulating the meshing kinematics with the generating rack. Subsequently, the tool path is adjusted by adding the additional motions for the machining axes within the inner closed loop to reuse the cutter with different shrinkage rates. The changing range of the shrinkage rate during cutter reutilization is determined by applying the outer closed loop. The numerical examples verify the effectiveness and practicality of the proposed method.