Reduction of friction in compression of plates by load pulsation

To prevent a sharp rise in load in compression of plates, a compression process using load pulsation was developed. In this process, the compression load is partially released during the forming to re-lubricate the surfaces of the plate. Gaps on the outer surfaces of the plate were caused in each release of unload by the difference in elastic recovery between the die and the plate, and the liquid lubricant is automatically fed into the gap. In the compression of an aluminium alloy plate, the effects of the releasing ratio of the load and the number of release on the reduction in compressive load were examined. Compressive load was considerably reduced by the load pulsation, and the thickness of the compressed plate was decreased. The occurrence of the gaps in the partial release of load was verified by corroding the surfaces of the plate in a compression experiment. It was found that the load pulsation having the automatic re-lubrication function is effective in preventing the increase in the load in the compression of plates.