RP of Thin Sheet Metal Parts

From: Ferrill, Jess B (bferrill@amp.com)
Date: Thu Mar 19 1998 - 16:05:30 EET

In the electrical connector business we frequently need to make rapid
prototypes of small thin metal parts (typically 0.005 to 0.015 inch or
0.13 to 0.38 mm. thick) to tolerances in the range of +/-.005 inch (0.1
mm) or better. The parts might have rectangular or round openings,
interrupted slots, tabs, etc. The narrowest cut slots or holes would be
about 0.015 to 0.020 inch (0.40 mm) wide. (The finished or profiled flat
part might be thought of as similar to a single paper doll cutout).

The profiled parts may then be formed by folding into the final shapes.
For our quick prototypes we currently use wire and plunge EDM or
photoetching followed by hand forming using prototype forming dies in a
small press. Materials might be copper alloys or stainless steel. Sheet
raw material sizes could be several inches per side on up to feet, but
individual parts are normally less than three or four inches in the
longest dimension. Typical prototype runs might be several hundred
individual parts. Capital costs of the equipment are less a concern
than time required to produce several hundred parts. Our ideal system
would also be capable of
producing thousands of parts until a production stamping dieset could be

I wonder if anyone has any fresh ideas. The ideal method would be
controlled from a solid CAD model or similar quickly generated CAD
layout (Pro/E with sheet metal module available).
The ability to cut stacked multiple sheets might offer a speed advantage

I am exploring the following methods to cut the profile shapes in flat

1) Laser cutting: (suitable for thin metals?, clean edges?, shiny
surfaces a problem?)
2) CNC punching or nibbling: (small precision parts, need for lots of
special punches? speed?)
3) Abrasive water jet: (capable of narrow slots?)
4) Plasma jet: (clean smooth edges?, capable of narrow slots?)

Any other ideas or comments on the above would be appreciated!

Thank you,

Britt Ferrill
AMP, Inc.
(336) 727-5387

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