Piercing (metalworking)

From Wikipedia, the free encyclopedia

This article does not cite any references or sources. (June 2007) Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed.

This article or section contains instructions, advice, or how-to content. The purpose of Wikipedia is to present facts, not to teach subject matter. Please help improve this article by removing or rewriting the how-to content, which may qualify for a move to http://www.wikihow.com/ or http://howto.wikia.com/.

The process of piercing or forming a hole of desired shape typically, in sheet metal. The sheet metal is placed between a male and female tool members namely, the punch and die. The amount of clearance between a punch and die for piercing is governed by the thickness and strength of the work-piece material being pierced. The punch-die clearance determines the load or pressure experienced at the cutting edge of the tool, commonly known as point pressure. Excessive point pressure can lead to accelerated wear and ultimately even catastropic failure. Material specific piercing guidelines typically available in tool and die maker handbooks. As a general rule of thumb, for thin materials, the clearance should be small and there should be a sliding fit to prevent ragged edges or burrs. For thicker materials, there should be significantly higher clearance. Burr height is typically used as an index to measure tool wear as it is easiest to measure during production.