沖壓加工跳屑現象之改善

Abstract

跳屑現象在沖壓過程當中是常久以來一直存在的問題，然而防止的對策亦是各家說法不一，各項採取預防改善對策及此方面的問題都是由操作沖壓作業者憑藉經驗去設法減少事故之發生；對於跳屑產生的條件及原因缺乏深入的理解，更沒有系統化的探討，而未來沖壓作業必將朝自動化及無人化進展，被加工材及成品更是要求尺寸及形狀精度品質情況下，在自動化或無人作業發生跳屑的行為，將直接或間接造成沖頭及母模之破裂或折損，使沖壓製品表面壓痕而影響製品品質。嚴重的情況將造成沖壓線停機而使得生產性大為降低，造成很大的損失。 本研究探討沖壓材料硬度、沖頭-沖模間隙、沖頭倒角、沖頭刀刃的鈍銳等四個主要加工參數對跳屑產生的影響，並以田口式參數設計規劃實驗及運用DOE實驗設計法，進行實驗分析來改善目前跳屑問題。 實驗結果得到採用較小間隙、較軟材質、且利用沖頭之倒角方式可以改善跳屑的現象達到順利生產之目的。

The “scrap bump up” phenomenon in blanking process has been existing for very long time. Engineers in the field adopt every possible countermeasures to prevent it. Most of these countermeasures depend on operator's experience. Due to lack of understanding for scrap bump up’s formation mechanism, there is no systematized discussion . However, with the progress in manufacture automation, scrap bump up has becoming more and more important. Bump up of the scraps in automated manufacturing process will cause the punch and die’s breakdown directly or indirectly. It induces scrap marks on blanking’s product and influences the quality of the products. In some situations the phenomenon will cause shut down of the entire production line.

The purpose of this research is to investigate the influence of four main processing parameters：material hardness、punch and die clearance、punch chamfer、punch radii. On the formation of scrap bunp up, Taguchi experimental analysis was adopted for the investigation. Experiment results indicate that smaller die and punch clearance, soft materials and proper selection of the punch chamfer radius will prevent the scrap bump up in blanking.