Plasma Transfer Arc Welding - Novel Method in Tool Reconditioning 2011-28-0075

Manufacturing processes play a major role not only in the attainment of high product quality, but also in the reduction of manufacturing and consequently also product costs. In manufacturing industries tools used are of major importance in this respect, as it is very expensive and critical in the process since it is tool dominant process and their job to convert products or components. In mass productions, wear and chipping of tools is inevitable. Hence reconditioning of tools play vital role since it is not possible to discard the tools for minor damages or flaw, as the tool cost is very high and expensive. However there are variables to consider geometry, material, defect and coating all play a part in driving the decision to recondition a tool.

The processes generally used for reconditioning of tools are welding overlays, grinding, machining and using it for next applicable size etc. There tend to be disadvantages like haz softening, tool reusable after repeated grinding, chipping off, lesser life etc. The latest trend or new techniques used for the reconditioning of tools is plasma transfer deposition or powder plasma welding (PPW) with the appropriate selection of proper powder composition. It is a process that deposits very precise coatings of perfectly controlled alloys on mechanical parts that are subject to intense wear, significantly extending their service life. We have attempted the reconditioning of our tool using Co-Cr based alloys with the hardness of 70 HRC. The PTA coating not only yielded the better overlays than the base tool but also increased the forming characteristics by producing the part aesthetically better. The process given the way to recondition the tool for more than 3 times and life of the tool become indefinite.