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Normsthename
12-11-2007, 02:35 PM
I have a client that wants me to produce 400 parts all the same.
The part is a simple company Logo name (6 letters) with 6mm (1/4") high letters on a 2mm base plate.
I have routed a prototype out of acylic and they are happy with it.
But, my CNC router will be machining these for upto 80 hours :eek:
So I had the idea of molding the parts.
The part needs to be white opaque material when finished, and is 190mm (7 1/2" x 30mm(1 1/4") in size.
Anyone know what material / procedure that I could use for this?

TIA

Andy

beone
12-11-2007, 03:33 PM
go to MicroMark.com,get their 2 part silicon mold material, make rubber mold, then cast with their urethane plastic (I wouldn't use the fastest(3min) ittl burn you) to cast. it starts clear but sets white. if not white enough, get some of the white tinting color.
Dave

Normsthename
12-11-2007, 05:10 PM
go to MicroMark.com,get their 2 part silicon mold material, make rubber mold, then cast with their urethane plastic (I wouldn't use the fastest(3min) ittl burn you) to cast. it starts clear but sets white. if not white enough, get some of the white tinting color.
Dave
Thanks Dave for your reply :)
I have had a look at the materials you suggested and they look perfect!
Would I be able to machine a mould out of acylic using my CNC router, and then take a mould off of that using the Silicone.
Then produce the actual part using the urethane?
How good a finish does the mould have to be for the silicone not to stick?

Thanks

Andy

Chuck Reamer
12-11-2007, 07:01 PM
We cast silicon in molds all the time, we usually make the molds out of UHMW polyethylene and they release with very little problems. A really good surface finish will make the final part look better so make it as smooth as possible.

We usually use Smooth On products and have had no problems with them to date.

beone
12-11-2007, 09:03 PM
You got it. Machine the master part, then make a silicon mold off it. This type of silicon mold material will not stick to anything but itself(so they say). then cast the parts for the customer out of urethane.
do the part well, the silicon picks up increadible detail. I don't know how many parts you can get per mold--probably not 400.
Dave

Normsthename
12-12-2007, 06:34 AM
I don't know how many parts you can get per mold--probably not 400
I was planning on machining a multi-part mould (8 per mould) so it would have to do 50 mouldings approx.
I will possibly also make another silicone mould to speed up the process :)

Thanks

Andy

High Seas
12-12-2007, 06:43 AM
Sounds like a brilliant plan - Smooth-on products are great - they have metal powders you may want to experiment with too (read - higher price for cold cast bronze) bits. Be sure an pop some pics here to show your results if your custmers permit!
:cheers: Jim

High Seas
12-12-2007, 09:25 AM
Sounds like a brilliant plan - Smooth-on products are great - they have metal powders you may want to experiment with too (read - higher price for cold cast bronze) bits. Be sure an pop some pics here to show your results if your custmers permit!
:cheers: Jim