dies can be reduced and maintained, the wall thickness of the can be controlled and reduced. All these functions are dependent on the directionality and control of the surface finish on both components.
The punch must have the random isotropic surface discussed in #2 above and the dies must have a negatively skewed surface, discussed in #1 above, that is in the direction of the drawn material (perpendicular to the diameter of the die). When all these criteria are met, one can expect bright OD finished cans that strip eas- ily (reducing scrap) and have a minimally thick wall. Wall thickness is not a trivial matter—savings of up to $10M per year per 0.001" (0.0254-mm) wall thickness reduction in a given can plant have been reported. To summarize: Mass media finishing techniques (barrel, vibratory, centrifugal and spindle finish) can be used to improve part performance and service life, and these processes can be tailored or modified to amplify this effect. Although the ability of these processes to drive down deburring and surface finishing costs when compared to manual procedures is well known and documented, their ability to dramatically affect part performance and service life is not widely recognized, nor well understood.
Abundant opportunities exist for part performance and part life improvement with substantial economic advantages. All that is required is a more thoughtful and purposeful approach to the selection and implementation of the mass finishing processes available to manufacturers. ME
Further Reading
1. Massarsky, Dr. M. L., Davidson, D. A. “Turbo-Charged Abrasive Machining Offers Consistency, Uniformity,” Products Finishing, June 2012 Vol. 76, No. 9, pp. 24-27, Cincinatti, OH: Gardner Publications
2. Clark, Jack, Massarsky, Dr. M. L., Davidson, D. A. “It’s the Finish That Counts”, Metal Finishing, July 2005, pp 24-29, White Plains, NY: Elsevier Science
3. Davidson, D. A., “Precision Finishing Processes in Centrifugal Barrel Equipment,” Metal Finishing, July/August 2005, pp 65-67. White Plains, NY: Elsevier Science
4. Massarsky, Dr. M. L., Davidson, D. A., “Turbo-Abrasive Machining and Turbo-Polishing in the Continuous Flow Manufacturing Environment”, SME Technical Paper MR99-264, [Conference Proceedings: 3rd International Machining and Grinding Conference, Cincinnati, OH, Oct 4–7, 1999] Dearborn, MI: Society of Manufacturing Engineers, 1999.
5.
Davidson, D. A., “Surface Condition Impacts Part Performance,” Metal Finishing, February 2007, White Plains, NY: Elsevier Science
6. Gillespie, LaRoux, Mass Finishing Handbook, pp 68-69, New York, NY: Industrial Press, 2007