Precision Grinding of the Large Aspect Ratio Micro-Tooth Internal Threads with Ceramic-Bond CBN Wheels

This paper conducted research on precision grinding of the large aspect ratio internal threads with ceramic-bond CBN wheels. Firstly, a combinatorial truing method by laser and mechanical truing for ceramic-bond CBN grinding wheels was developed. The effects of laser power, truing time, and truing depth on the laser truing process were investigated. In order to enhance truing accuracy, a predictive model for subsequent mechanical truing parameters was established via response surface methodology. Secondly, based on the in-situ measurement system, the axial and radial tool setting methods of the internal threads are established, and the standardized tool setting steps are constructed. The axial tool setting error is less than 5 μm, and the radial tool setting error is less than 10 μm. Finally, the influence of truing frequency on thread profile errors was investigated, and a mathematical model relating worn wheel angles to maximum allowable grinding depths was established. Based on the above process, the large aspect ratio micro-tooth internal threads with average profile angle 90.12°, mean pitch diameter 21.062 mm, average pitch 1 mm, and mean root radius 85 μm was ground.