Slashdot Mirror
Making Casings for Prototype Electronic Devices?
kiddailey asks: "I'm working on a project for self-enrichment that involves creating a working prototype of an electronic device. I've made a model of the basic shape of the device out of Sculpey (tm) and want to use it as a mold to make the actual plastic housing that I can then insert the electronics into. Has anyone done something like this before? Is there any way to achieve this without a significant R&D buget?"
I generally use wood, light, strong, cheap, but labour intensive to shape. And flammable :)
-Yarn - Rio Karma: Excellent
You could send your design as a cad file to Toybuilders and they'll 3d print you one.
However as you've already made your model you'll want it scanned. There are companies that will do this for you too - though they dont quote prices like Toybuilders do, so I guess it'll be expensive.
I noticed from Neco's page that a Rapid Prototyping and Manufacturing exhibition is taking place in Cincinatti on Tuesday (29th April) until May 2. If you get the list of exhibitors I am sure someone will be able to help.
Cheers,
Baz
You could always use that as a 'plug' (male model) from which to make a female mold (out of glassfibre or plaster).
You can then make a thin shell casing from the female mold, in glassfibre or carbon (looks _very_ cool).
Hydrocal is a hard plaster/cement type compound that works _really_ well for short run molds, or for one-off parts, generic plaster works well. If the shape is complex, eg. has undercuts, then you'll need to make the mold from silicone. Check out Special Effect Supply, they seem to stock a lot of the stuff.
Once you have the mold, you can then lay up a part using polyester (Yuck!) or epoxy resin and glass, carbon or kevlar fabric. Glass fabrics are now also available in colors (I've seen red, silver and blue) if you don't want to paint the final part. Another option is to cast the part using a polyurethane resin, (try ProCast
)
You will probably have to make a multi-part mold in order to define a wall thickness, though.
Maybe check out FibreGlast for some ideas.
There are _much_ more elegant ways to do this (eg. CNC machining), but molded glass or polyurethane is probably about the easiest / cheapest method of prototyping this sort of thing. With a bit of effort, you can get _really_ professional looking results.
It depends on how crazy you want to get. If it's going to metal, try going down to your local machine shop and asking them, OR post a question on Rec.crafts.metalworking
Even if it needs to be cast, that can be done (esp if you want it done in Al) - you could look up "Backyard Foundry"
Of course, now we're talking about a REAL geek hobby - Metalworking! Hot metal, dangerious tools, and it takes a brain
-- 73 de KG2V For the Children - RKBA! "You are what you do when it counts" - the Masso
Check out Lindsay books. Make sure you get a dead tree catalog, not all their books are online. They have books on how to do a lot of cool things that you can apply. Glass, sheet metal, poured metal, pottery, Plastic (injection or vacuum) molding. All on a dot it yourself from scraps. Most of their books are from the early 1900's, so they are obsolete compared to modern mythods, but still useful. Note that you would have to be crazy to do some of what they will tell you how to do. It would still be fun to do it though.
Yahoo has a group of Hobbicast If you are interested in metal casting (my personal interest). I'm sure there are other groups for those interested in other materials.
Have fun!
CNC Machining - Perfect - we used to have it done all the time
Charlie
-- 73 de KG2V For the Children - RKBA! "You are what you do when it counts" - the Masso
Well, sheet metal is easy, it's stamped. For about $500 for a decent compressor, and another $200 for a 40 ton hydrraulic press (this is how much pressure, not how much it weighs) you'd have the basic machinery. Small dies would be rather cheap, maybe as little as 5-10 hours work, and $100 raw materials. A die, by the way, fits in the press, and acts like a cookie cutter. It can cut, bend, and stretch metal, even into shapes that you wouldn't think possible.
I've been wanting to do this for awhile, but even the simplest die still requires a decent machine shop. Harbor Freight Tools does have a cheapy mill (metal cutting/shaping tool) for about $300....
Plastic pieces require an injection molding maachine. The molds are carved out of aluminum generally, and would be cheap to make. They're chemically treated (anodized), and I've found a local firm that will do it cheaply (about $20 per). Generally, even used injection mold machines are too expensive for the hobbyist ($5000+) but I've heard of people building their own.
If you'rer serious, but strapped for cash, a dremel and some vises can do alot for simple things. It is only sheet metal, after all, and if you're careful, you can bend it precisely and attractively. Never been able to make them look as slick or mass produced, though.