It needs long time to carve a molding die of bumper, which has a large and deep cavity. To shorten the milling time, we must make the machining more performable and accurate, and develop the new technology of CAM. In the milling sequence, Primary Roughing, which cut out 90% of the stock, should be more and more performable. So we established Tilt-Plunging and Curve-Fit Spiral Cutting techniques. These techniques will reduce lateral force to the tool, and make remains more small. With the techniques, we reduced both machining and NCdata preparing time to one half. 1 ref., 14 figs.