Page 29 - MetalForming November 2009

Using a different grade of tool steel for each job likely will not allow metalform- ers to enjoy predictable performance.
2) Heat treat correctly. The effort required to correctly heat treat tool- steel components is significant in terms of time and money. However, no other single step will have greater impact on how the tooling will perform. Stam- pers must follow the proper procedure —without shortcuts—to realize the full capability of a particular grade of tool steel. A tool that has been poorly heat treated might work some of the time, but eventually the result will be incon- sistent performance and waste. This is even more evident when using high- alloy, high-performance tool steels that can tend to be much less forgiving.
As a side note, manufacturers of heat treating equipment have made signifi- cant advances in recent years, such as high-pressure quench vacuum furnaces. Metalformers should seek opportunities to leverage those improvements.
3) Avoid inflicting unintentional damage. Work to maintain control of surface integrity when finishing the tooling. For example, overly aggressive grinding or EDM machining can cause poor edge retention, premature wear and an apparent loss of toughness. Care taken during finishing operations to minimize surface damage, remove burrs and maintain good edge quality will provide real value in the end. The more demanding the application, the more critical these considerations become.
Problem Solving and Continuous Improvement
Take a disciplined approach, whether attempting to improve tool perform- ance or actually dealing with a tool fail- ure. The challenge is to accurately deter- mine the primary constraint or root cause of the failure. If at all possible, routinely examine tooling while in serv- ice to gain a clear understanding of how wear develops. By the time the die gets back to the toolroom, it might not be possible to determine how the problem initiated, particularly if a catastrophic failure resulted. Metalformers also
should keep accurate and timely records concerning the specific identity of the tool-steel items used.
Having assembled all of the available facts related to a performance issue or tool failure, begin to untangle the cause- and-effect relationships that underlie the problem. Consider all of the factors that possibly could play a role, beginning with the design of the tooling through
to its actual handling and maintenance in service. The metalformer may need to perform several iterations of lean prob- lem-solving methodology to obtain the desired level of improvement. An actual metallurgical-lab analysis may be indi- cated to provide confirmation of any suspected issues related to tool-steel qual- ity, heat treatment or surface damage. If these issues can be ruled out, the stamper
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