Re: Rapid Tooling

From: Brock Hinzmann (
Date: Fri Feb 16 1996 - 02:31:50 EET

I am also very interested in your experiences with Rapid Tooling. I have been
told that injection molded parts must hold to tolerances of plus or minus
0.0002 inch (0.005 millimeter), but that Keltool and RapidTool (DTM process)
generally allow only 0.005 inch (0.127 mm). Although Keltool and RapidTool are
capable of producing at least 10,000 parts, are such parts accurate enough for
your application? Since the requirements for each application may vary, you
might explain your application when you respond.

It is also my understanding that epoxy mold inserts are in common use, but
that they are useful for only 1000 parts or less. What kind of accuracies are
you able to get with those tools. How many parts, with what kind of accuracy,
are you able to produce from epoxy inserts, in your experience? Also, if you
are interested in working with someone to develop a solution to such problems,
let me know.

Brock Hinzmann
SRI International
333 Ravenswood Avenue
Menlo Park, California 94025
voice: +1 +415 859-4350
fax: +1 +415 859-4544


We are looking for efficient "Rapid Tooling" solutions for injection molded
parts. The product is what we can call a "Marginal product". This means that
the forecasted production volume is so low that normal steel-tooling it is
out of reach from a cost point of view. Altogether more than 20 different
parts are included in this product, so here is a great potential of reducing
development time and time to market by new techniques.

The size and complexity of each part varies from rather big ones
(420x250x150mm)with less complexity (single pull, parted along a simple
parting line), to the smaller ones (20x10x10mm) with moderate to high
complexity (multipple pull and more intrecated parting line). Most of the
parts will be found in the group of small ones.

Required accuracy, repeatability and surface finish will be highest for the
smallest parts, comparable to what is normal to parts made with traditional

The total product volume will be 10 000 pcs. of each part.
We are interested in "Rapid Tooling solutions" which can be made from both
master-models and 3D-CAD files.
It is also a possibility to combine tooling for this product with Rapid

Are there someone out there who know companies or service- bureaus that are
capable of doing efficient "Rapid Tooling" solutions? The parts should
preferably also be produced external.

Keltool is probably a possible solution for some of these parts. What is the
experienece with Keltool, or with other rapid tooling processes out there?

Regards: Nils A

Nils Aksel Ruud
SINTEF Rapid Prototyping and Tooling
Rich. Birkelandsv. 2B
N-7034 Trondheim

Phon: + 47-73597125
Fax: + 47-73593670

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