Grinding worm wear evaluation and its influence on gear surface topography in continuous generating gear grinding

Due to complex geometry and movement involved in continuous generating gear grinding, the grinding worm wear characterization is different from that in regular grinding processes. Grinding worm wear evaluation with accumulated removed material volume was investigated through wear status evolution experiments. By changing grinding parameters in orthogonal experiments, grinding worm surfaces with various wear status and their resulting gear surface roughness were obtained. The results show that the fractal dimension could be used to roughly quantify grinding worm wear status. A nearly linear relationship was found between the fractal dimension and the removed material volume. Grinding speed, normal stock, feed rate, and shifting value were proven to have great influence on grinding worm wear. A significant negative correlation was found between the fractal dimension and surface roughness. However, due to shifting movement, both coarse grinding parameters and finished grinding parameters can affect gear surface. Smaller fractal dimensions were found to result in smoother gear surfaces and vice versa. Based on the result, grinding parameters in continuous generating grinding were recommended. Grinding speed should be as high as possible considering the machine tool capability. Normal stock of 0.02–0.09 mm, feed rate of 50–100 mm/min, and shifting value of 7 mm should be adopted in finished grinding.