Influence of servo press slide motion on dimensional accuracy of cold backward extruded aluminum alloy

摘要

A crank press is not controlled the slide motion. But a servo press is flexible to control the slide motion. For examples, it is possible that the punch stroke is kept at bottom dead point and the direction of crank rotation is reversed during deformation. Furthermore, slide oscillation is set up during one stroke. So the servo press is sometimes used to sheet forming. However it is not use so much for bulk forming. We focus influence of the servo press slide motion on dimensional accuracy of backward extrusion for aluminum alloy by using the servo press. We use the servo press H1F80 (KOMATSU). The stroke speed is set 40 spm. It means that the average speed is about 173 mm/s. And we select typical four slide motions. The specimen is 30.1 mm in diameter and 19.0 mm in height. And it treated aluminum fluoride and soap coating for the lubricant. The reduction in height is 50% and the stroke is 10 mm. We measure the variation of inner and outer diameter, and the variation of roundness in both inner and outer diameter. As the result, the motion, which is rose up the punch at two times above from the bottom dead point, is the best dimensional accuracy of these four slide motions.