Page 14 - MetalForming November 2022

Tooling by Design
instead result from a high-quality sur- face-preparation process. To determine this, verify that the die component has been machined with the proper amount of clearance to accommodate thickening, and polish to a level accept- able for coating application. Next, install the die sections in the die with- out coating them and then document the results.
3. Address adhesive-wear problems directly.
If galling persists, increase the wear resistance of the die component and reduce the contact friction between the tooling and the workpiece. This requires proper tool-steel selection and heat treatment to ensure surface hard- ness that resists abrasive wear. Proper lubrication selection and application reduces contact friction.
4. Address lubrication only after complying with rules 1 through 3.
Usually, lubrication represents the first countermeasure attempted—a quick, low-cost solution—when galling persists. However, if not the root cause, lubrication proves a short-lived solu- tion. As changes in material thickness, friction conditions, process tempera- ture and adhesive-wear conditions vary over time, so will the effectiveness of the lubricant. The typical countermea- sure: Change the lubricant concentra- tion or change out for something “bet- ter.” Oftentimes, the problem area ends up flooded with a constant flow of lubricant, creating a housekeeping issue and increased operational costs.
Using the proper lubricant and con- trolling its application (volume and location) prove crucial to a successful stamping operation. However, this approach is most effective when not used to offset die-related problems
Follow these four rules before pur- suing surface treatments. Otherwise, the expensive coating may do nothing more than cover up an underlying— and perhaps less-expensive—die problem. MF
Next month: Addressing tool steel chipping and wear.
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