Don't forget that, in addition to SLA as amaster for Keltool cnc patterns
or cnc negatives also work out, sometimes giving more precise results.
Keltool was a process before the SLA machine was born.
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.
>
>>Keltool, a metal-sintering technology
>>invented by 3M Co. to rapidly and economically
>>create tools for small metal parts (no larger than 6 inches) that could be
>>reproduced in quantities from several hundred to millions.
>>
>>An .STL master is used to make long-life production
>>tooling from Stellite, A-6 tool steel, and a composite material of A-6 tool
>>steel, tungsten carbide, and a copper alloy. In the composite material, the
>>dispersion of tungsten carbide enhances wear resistance, while copper
>>improves thermal conductivity by about 30 percent.
>>
>>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
>
>
>
>
Randy Erickson
erickson@metalcast.com
Metalcast Engineering
4800 Coliseum Way
Oakland, CA 94601
510-534-2320 fx 510-536-3322
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