Page 38 - MetalForming January 2017
P. 38

 Confused About Tool Coatings?
Key areas abound where manufacturers can identify stamping challenges and narrow coating options to avoid a lack of success or, worse, even more problems.
Stamping operations often can leave fabricators perplexed and frustrated with tooling failures and the quality of finished parts. Galling, microfractures, chipping, breakage and numerous other chal- lenges lead to costly downtime, unnec- essary tool wear and added costs for frequent tool sharpening or remanu- facturing.
When the problem isn’t obvious, and continued troubleshooting leads
Jeremy Edson is the global product man- ager for the stamping division at Wilson Tool International, White Bear Lake, MN: 866/752-6531;
These Tips Will Help
to even more confounding results, combining the right coating for the particular application and material can make the difference.
Incorporating coatings can help manufacturers in a number of ways, by:
• Eliminating secondary operations • Producing higher-quality parts
• Increasing tool life
• Increasing tool-edge life
• Adding lubricity
• Minimizing adhesion. Determining the ideal combination
of coating, application and material can be a lesson in trial and error. There are key areas, however, where metal- formers can identify stamping chal- lenges and narrow the options to avoid a lack of success or, worse, even more problems.
Assess the Application
A simple task that often yields com- plex information, assessing the appli- cation and identifying potential pitfalls and challenge areas are the first steps in identifying the coating and tool-
steel combination that will work best. Piercing, blanking, trimming, form- ing, high-pressure forming, high-heat applications, high-impact applica- tions—all of these present unique sets of challenges when selecting the right tool coating. A basic coating will garner results and add longer life to the tool,
no matter the type of application. When a basic coating fails to provide sufficient results, however, metalform- ers can move to a harder coating. For piercing, blanking and forming appli- cations in particular, coatings with a hardness of 2900 to 4000 HV are ideal. The coefficient of friction for these coatings should be between 0.3 and
0.6 for maximum results.
Tool coatings for these types of
applications include proprietary coat- ings available from tooling manufac- turers, as well as TiCrN and TiZrN. While all of these coatings result in increased wear resistance, improved surface finish and added toughness, many proprietary options and TiCrN are particularly helpful in reducing galling.
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