An experimental study on the development and application of ultra high accuracy and high-speed groove die set

摘要

This research designed and developed a groove type die set which improved life span of the die set by eliminating point-contacts of steel balls with the guide post. The guide post consisted of a steel-ball retainer, a steel-ball retainer stopper, a guide bush, a guide pin, a snap ring, and a spring. The steel-ball retainer has 72 holes with 8 columns of 9 holes in each column. The inner surface of the guide bush was grinded (surface roughness: Ra = 0.2 μm, accuracy: 0 ～ -0.002 mm) after NC turning and it was treated with heat. Also, a line of small intermediate pocket was processed inside of the guide bush for lubrication and elimination of foreign materials. Guide grooves for steel balls were processed using a wire EDM (Electrical Discharge Machining) after the heat treatment. With such a design of the guide post stated above, loads against steel balls could be dispersed greatly by the line contacts through the guide groove between the guide pin and the guide bush, and the life span of the guide post could be expanded semi-permanently.