Ask HN: How does one prototype a physical product?

#1

Post by rgr » Thu, Jan 22, 2009, 7:47 PM UTC

I have an idea for a product I want to prototype. It's a physical object, sort of like a plastic toy. It doesn't have a microprocessor or any electronics for that matter. Unfortunately, my background is in software, and I don't know zilch about industrial or mechanical engineering, especially when it comes to plastic manufacturing (unless you consider playing with legos as a kid relevant experience).

Where do I start? Any pointers will be greatly appreciated.

Re: Ask HN: How does one prototype a physical product?

#2

Post by ph0rque » Thu, Jan 22, 2009, 7:55 PM UTC

Make a CAD model of it, then send that file to get it prototyped. I've used http://www.redeyeondemand.com and http://www.quickparts.com before; didn't have any extreme experiences with either of them (either good or bad).

Re: Ask HN: How does one prototype a physical product?

#3

Post by npk » Thu, Jan 22, 2009, 8:24 PM UTC

How complicated is it? Can you make it yourself? It's probably best if you do. If you have something you want to make in quantitiy, you'll want to hire someone who is experienced with tooling up a factory efficiently. What you're doing is not really engineering, but more like "drafting".

If you live in the bay area: http://techshop.ws/

If it's relatively simple, you can find a CAM house that will build the part for you, but then it becomes expensive. This place has an FDM house (wikipedia for details): http://www.emachineshop.com

You can find cheap drafters on craigslist who can make a solid model of your part that you would ship to the machine shop.

good luck

Re: Ask HN: How does one prototype a physical product?

#4

Post by NonEUCitizen » Thu, Jan 22, 2009, 8:33 PM UTC

from visiting techshop, i found out that google SketchUp (plus a plugin) can be used as the CAD tool for their Dimension SST. SketchUp tutorials: http://sketchup.google.com/training/videos.html

Re: Ask HN: How does one prototype a physical product?

#5

Post by bprater » Thu, Jan 22, 2009, 8:35 PM UTC

Great question.

There is very little magic to the prototyping phase. Google 'rapid prototype' (maybe add 'plastic' to it) and find a shop that has a price that is in your budget. (The price usually has to do with size of the blank they will work on for you.)

Spend a bit of time looking at the different methods of creating a prototype from plastic. Some use a type of "printer", others carve it from a chunk of plastic. Find out the pros-and-cons of the different methods. (Cost vs accuracy vs material.)

Find out what software format they import from and build your prototype in software that can export in that format. Email them the data, your credit card number, and in a few days, you should have your prototype!

Enjoy this phase -- the tricky/expensive part is going from the prototype phase to production.

Re: Ask HN: How does one prototype a physical product?

#6

Post by tstegart » Thu, Jan 22, 2009, 8:38 PM UTC

Clay, paper mache, foam, legos, wire, sheet metal, balsa, glass, wood. You can carve a mold and inject molten plastic (styrofoam beads) at home (preferably well ventilated). You can also melt soft metals and use sand molds.

Thats simple prototyping. To get an exact replica, in the same materials you want to use for final production, there are shops that will make plastic or metal molds from CAD files, or can carve with lathes, etc.

Edit, I should add wax. Its actually an incredible material for prototyping. It carves especially well, and you can add pieces if they fall off accidentally, or you decide to change the design. If you don't like it, melt it down and form a new block. Lastly, when you're ready to make a mold, you can encase it in sand or another substance, and then melt the wax away to leave your shape.

Re: Ask HN: How does one prototype a physical product?

#7

Post by gamache » Thu, Jan 22, 2009, 8:42 PM UTC

How about a RepRap, the Replicating Rapid Prototyper? http://www.reprap.org

Re: Ask HN: How does one prototype a physical product?

#8

Post by mhb » Thu, Jan 22, 2009, 9:02 PM UTC

For 3D modeling, I like Rhino (http://www.rhino3d.com) ($800). The support the company provides on their usenet group is unbelievably good and there is a huge community of extraordinarily helpful users.

Shapeways for rapid prototyping (http://www.shapeways.com). Many people who use Shapeways use Blender which is a free 3D modeler.

Re: Ask HN: How does one prototype a physical product?

#9

Post by brk » Thu, Jan 22, 2009, 9:18 PM UTC

I've done this a few times. Mostly for industrial design projects like product bezels and cases and such.

I usually "carve" something out of wood and paint to get an idea of physical appearances, fit, etc. From that I'll usually make a fiberglass model (so that I can test fit something that is close to the actual dimensions/thickness of the actual item). Then I Google for a local freelance CNC shop in my area and commission a formal CAD drawing and prototype milled out of a plastic.

From there you can generally figure if your design is right for injection molding, vacuum forming, etc. Find the right CAD guy and they can often help guide you somewhat with the design as well.

Happy to help if you need more info.

Re: Ask HN: How does one prototype a physical product?

#10

Post by knieveltech » Thu, Jan 22, 2009, 9:19 PM UTC

It doesn't make sense to bother with jobbing out initial fabrication of a prototype unless you've got VERY deep pockets and absolutely plan on going into production. Unless both of these are true I suggest modeling the part from balsa or foam and then cast your prototype in resin or low temperature metal.