hi, I am designing an electronic tool as a hobby project. As I want it to be professional an durable made I use the prototype production of the electronic board houses to produce the boards I designed. the soldering i did myself. Now its time to start on the housing of my project and I wondered if there is low cost prototype service that allows me to order pieces out of plastic as i designed them. If I search for plastic prototyping there is a 3D printer or an expensive mold needed. But in my case i just need smal pieces and not a great amount of them. hopefully you (the members of mechanicaldesignforum) can help me out with this question. note: i didn't designed them yet on a 3D program. First I want to know some design rules and minimum requirements, possibilities of material and especialy the costs
for rapid prototyping you can do: SLA, but that is typically brittle and lower strength plastic. It is fast and the cheapest of the RP processes SLS offers tougher resins (nylon) but parts are typically a little fuzzy - ot have a lesser surface finish FDM is pretty good mechanical properties but a funky surface finish the next step up is quick turn machining such as FirstCut then if you need more than a couple of dozen parts you can do proto mold. They are the same company as first cut, but do aluminum tools. None of them are really inexpensive. If you want one or two "real" parts, meaning parts that you can actually use in the field, then SLS or machining would be the best bets. IMHO.
Hi keuninkske As 'maniacal_engineer' said - many of these rapid prototyping methods are not cheap. But then I suppose it depends on how big this assembly is and its use (handheld/desktop/on an oil rig). You could always try www.shapeways.com first. This will give you a cheap and quick way of assessing the design before you spend to much more. I use a local SLA company - about £120 for two halves of a TV remote sized box. Or maybe you could approach a local college and ask the design class to design and make you a box?? Could be fun! You could also just buy off-the-shelf boxes - http://www.pactecenclosures.com/ or http://www.okw.co.uk/ Good luck - would be good to see some photos of the finished product. Alex
I agree with the previous posts. When we are prototyping, we typically get the parts machined to prove the concept. This costs a lot less then going striaght to a molder. I've used First Cut in the past and have had great success. They can be a little pricy but their turn-a-round is really quick. Protomold has many limitaions in the molding aspect of it but they are still pretty quick. If really depends on the complexity of the part, what material you are going to use and how many you are going to be buying. These factors will really help determine what the best process is to use.
I don't see where anyone else has suggested using a master to create a temporary rubber mold. The material used for the part(s) would likely be a urethane, so you can choose your durometer (to a point). Depending on the complexity of the designs, the rubber mold could last for half a dozen parts or only one each (one each would make the process expensive). There are prototyping houses which specialize in doing this. It's not exactly cheap, but then with an elastic mold you may have the option of having undercuts and other features which might be tricky otherwise.
I agree with Mark, Vaccum casting would be a cost-effective prototyping way to produce around 20 samples made of PU (Polyurethanes
I use to work for a FDM machine supplier who also provided a small sub-contract service. The funky finish on the models can be reduced by using thinner layering, but this adds to the cost as it can double and treble the cycle time. To make the models smooth you can rub them down with scotchbrite or apply MEK.
