Re: RP of Thin Sheet Metal Parts

From: wayne l foss (
Date: Thu Mar 19 1998 - 18:32:13 EET

Ferrill, Jess B wrote:
> 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
> finished.
> 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
> material:
> 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
> For more information about the rp-ml, see


We have been looking at prototyping systems for printed wiring boards.
These circuit board plotters are like a mini-mill or router and remove
the copper layer from the board stock. They will also do engraving in
softer metals. The end mill bits are as small as 0.4mm dia. and drills
go down to 0.3mm dia. Try the following vendors:

LPKF CAD/CAM Systems, Inc at

T-Tec, Inc at

Also try venders that manufacture engraving equipment.


- Wayne L. Foss                  
- Engineering Services                     Phone  319/295-2631
- Rapid Prototyping Specialist             FAX  319/295-5429
- MS 106-176
- Rockwell Avionics & Communications	 
- 400 Collins Road, NE             
- Cedar Rapids, IA  52498-0001
DISCLAIMER: Unless otherwise indicated, this correspondence is personal
opinion and NOT an official statement of Rockwell Avionics &

For more information about the rp-ml, see

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