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geekhack Projects => Making Stuff Together! => Topic started by: Techpriest on Thu, 17 July 2014, 12:58:52

Title: Resin Plates
Post by: Techpriest on Thu, 17 July 2014, 12:58:52

Hey guys,
So my move to the midwest is finally complete but there is still a few things I need to do before I'm ready to start shipping aluminum plates again.

I've been thinking about the plates alot lately and wanted to see what you guys would think of cast resin plates?  I was thinking it would be an easy and low-cost solution that could be shipped fairly quickly and made on-demand in smaller batches.  Any opinions? Is this something you'd consider purchasing?

Thanks,
Techpriest

Title: Re: Resin Plates
Post by: Findecanor on Thu, 17 July 2014, 15:48:16

If I were you I would skip the idea of casting resin plates. To get started would take too much effort before you would be able to produce them in adequate quantity and quality, and if you skimp on that then that could hurt your reputation.
I have done stuff in urethane, epoxy and polyester. The RTV and casting resins shrink while curing and the resins are brittle, so you would still need to machine a new master with larger dimensions that take those things into account.
I think that laser-cut acrylic would be a better choice.

Title: Re: Resin Plates
Post by: jacobolus on Thu, 17 July 2014, 16:55:06

Probably easier and more reliable to use a water-jet cutter, a laser cutter, or a CNC mill, and cut them out of steel/aluminum/acrylic/wood/...

I’m sure you could figure out a way to make plates via injection molding or casting (or 3d printing, etc.), but it sounds a lot harder to get right, and most common plastics don’t seem like a good material for it anyway.

Title: Re: Resin Plates
Post by: Dodgy on Tue, 22 July 2014, 16:02:55

Resin casting plates would take some work, but, you might be able to do it on an open faced mold that's perfectly level. I think you could probably get away with casting them without any pressurization but degassing might be a bit of work. Not impossible, and thinking about it, you probably wouldn't need to actually mix as much resin as I'm imagining to fill the mold.

Title: Re: Resin Plates
Post by: Techpriest on Wed, 30 July 2014, 13:04:40

Thanks for the replies guys, will keep exploring and thinking of different ways to bring the cost down from laser cutting.

Title: Re: Resin Plates
Post by: dorkvader on Thu, 31 July 2014, 00:02:34

Quote from: Techpriest on Wed, 30 July 2014, 13:04:40

Thanks for the replies guys, will keep exploring and thinking of different ways to bring the cost down from laser cutting.

If only you had a hard vacuum handy, you could e-beam cut one with a CRT (which are very cheap, high power, easy to drive, and already focused). as it stands, you'll poison the cathode before you can get any real cutting done. Stupid atmosphere.

Title: Re: Resin Plates
Post by: Oobly on Thu, 31 July 2014, 07:50:47

I would think punched aluminium or steel would end up cheapest, but laser or water cut acrylic is nice.

Resins are usually rather brittle and I don't think I'd want to use it as a material for plates, but it could make for an interesting "solid" case and plate design, molded in one piece of resin (with the PCB and switches molded in, you'd have to seal the switches somehow I guess).

Title: Re: Resin Plates
Post by: dorkvader on Thu, 31 July 2014, 14:40:29

Quote from: Oobly on Thu, 31 July 2014, 07:50:47

I would think punched aluminium or steel would end up cheapest, but laser or water cut acrylic is nice.

Resins are usually rather brittle and I don't think I'd want to use it as a material for plates, but it could make for an interesting "solid" case and plate design, molded in one piece of resin (with the PCB and switches molded in, you'd have to seal the switches somehow I guess).

cheapest in quantity for sure, but the cost of manufacturing a die that large for a punch big enough to handle it is quite expensive.