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Punch and Die Relationships for Producing Projections

IP.com Disclosure Number: IPCOM000047907D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Goodrich, RA: AUTHOR

Abstract

It is well known to form projections in sheet metal for the purpose of facilitating resistance projection welding. Special consideration must be given to the punch and die relationships when producing projections in titanium metal and projections in low carbon steel for multi-component sheet metal assemblies. Recommended hot forming techniques for producing projections in titanium are not satisfactory because uniform dimensions are not achieved consistently. The proper punch and die relationships are dependent upon the material thickness, and the projections are formed in the thicker piece where the pieces to be joined are of unequal thickness. Fig.

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Punch and Die Relationships for Producing Projections

It is well known to form projections in sheet metal for the purpose of facilitating resistance projection welding. Special consideration must be given to the punch and die relationships when producing projections in titanium metal and projections in low carbon steel for multi-component sheet metal assemblies. Recommended hot forming techniques for producing projections in titanium are not satisfactory because uniform dimensions are not achieved consistently. The proper punch and die relationships are dependent upon the material thickness, and the projections are formed in the thicker piece where the pieces to be joined are of unequal thickness.

Fig. 1 illustrates a punch and die where C is the diameter of the die, DR is the spherical break radius, E is the height of the die cavity, F is the punch height, and JR is the blend radius. These dimensions in the past have not included the 2XJR blend radius. The lack of this dimension causes a high stress point in the sheet metal projection transition area, as shown at point 1 in Fig. 2. For materials 0.031 to 0.188 inch thick, the projection height is in .025 inch for multicomponent assemblies greater than four square inches and less than 1800 square inches. The largest permissible variation in projection height per machine sequence is 0.002"/component to be welded. To produce projections within this tolerance, a pressure pad stripper 20 is interposed between the pun...