FAILURE ANALYSIS OF A HIGH SPEED STEEL BLANKING MOULD MACHINED BY EDM

摘要

In the manufacture of a forming tool, in addition to the correct choice of the type of steel to be used, the sequence of machining operations is of fundamental importance to obtain high performance tools. Improper execution of the manufacturing run shall leads to premature failure of the mould during its life. The brisk failure of a blanking mould fabricated with HSS - PM S390, manufactured by Electrical Discharge Machining (EDM) is here examined. The initial steel block has been heat treated before machining to obtain the final shape and geometry of the mould. After the EDM process and grinding operations, the mould was given a TiN - PVD coating and put in service. The possible causes of the failure of the mould are hypothesized by controlling the overall production cycle, from the quality of the heat treatment to the accuracy of machining performed on the initial steel block.