At 04:29 PM 11/6/96 +0100, you wrote:
>Someone asked about Keltool. Here are excerpts from an article last year
>which describes it.
>
>>
>>In the Keltool process, a stereolithography part designed by a tool and mold
>>specialist is made as a negative of the final shape. The negative pattern is
>>placed in a box filled with RTV rubber, which cures and hardens. Ultrafine
>>metal powder (Stellite, A-6 tool steel particles) is then poured into the
>>rubber positive. The powder has some thermoplastic binder in it, as well as
>>a varied size distribution (from 0.5 to 20 microns) for tight packing and
>>high fill ratio. The molded powder form is heated in a low-temperature oven
>>(100 C) to create a green part. The green part is then demolded and fired in
>>a furnace at 1300 C, which burns out the binder and sinters the part
>>together. The sintered parts can then be infiltrated with copper to produce
>>a tool. The resulting small parts have dimensional accuracy to 0.001 inch
>>per linear inch.
>
>----------------------------------------------------
>Yakov Horenstein Tel: +39 2 65 35 12
>Milano, Italy Fax: +39 2 2900 6208
>
>
>
Hi Yakov,
Thanks for the article on Keltool it was very informative, up until the last
line,
which claims a accuracy of 0.001 inch per linear inch. What this section of
the article
didn't say was there is to my knowledge an 8% shrinkage overall from the
.STL master.
We have found that shrinkage can be the villan in any form of SLA
replacement material for tool creation.
I could be wrong and there may be recent improvement in the Keltool process.
I would like to hear from someone who can give us an update.
Regards,
Michael Wilson
Project Manager,
Polycarbonate Parts in "ACES build" mould
Aurora Search Inc. (Canada)
Email: art2part@unixg.ubc.ca
Web:http://www.interchg.ubc.ca/art2part
voice:604-644-1829
fax:403-282-1238
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