
Ask HN: mass-manufacture plastic - dobloon
I have a physical product with a finished design that I'd like to sell. Making the circuit is easy enough, but the way I made the plastic isn't scalable. I'd like to make 10-20 copies of my product. Ideally, there's some kind of cheap moldable plastic, anybody out there have any idea what I should use?
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rjprins
I've studied industrial design for a few years, here is what I can tell you:

Plastics is a very large subject and there are a lot of criteria that can be
involved. You criteria apparantly are:

    
    
      - Can be made in small series. (ie. no injection molding or extrusion)
      - Holds electrical circuitry.
      - Serves mainly the purpose of container. 
      (no exceptional stresses, no special features, 
      must be able to open and close in some way.)
      - Consumer product, so must have somewhat nice finish.
      - Should be tappable for screws?
      - Production accuracy within 1-2 millimeters?
      - Can be made in your own workshop?
    

Here are some small-series techniques you could look into:

    
    
      - (Resin) casting
      - Dip molding/casting
      - Heat molding
      - Spin casting
      - Vacuum forming
      - Hand laminating or spraying
    

I don't know what materials are exactly applicable to what technique, but for
your purpose some common materials are: PP, PS, Styrene-butadiene, ABS
(especially), PA6, Polyester (resin).

Goodluck!

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krschultz
Protomold.com is your best bet, ultimately you can make a larger run off the
molds where as milling won't tell you anything about the viability of it as an
injection molded product. Also injection molding is a bit more complicated
than just drawing up a shape so you might need some expertise if you are going
down that road.

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nkurz
I've been doing some home molding with High Impact Polystyrene (HIPS) and with
clear PETG. The polystyrene is opaque, white, strong, and particularly easy to
work with. It's also cheap (about $50 for a 1/8" 4'x8' sheet).

Vacuum molding at home with an oven and a vacuum cleaner can produce
surprisingly good results. Searching the web for "vacuum molding" or "vacuum
forming" should turn up some decent tutorials.

TAPPlastics.com is pretty good for small quantities (especially if you are
near one of their stores), but others (like Interstate Plastics) have better
prices on full sheets. TAP has HIPS at their store near me, although I don't
see it listed on their web site.

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cmos
I always try and find a way to make it out of metal in smaller quantities (and
larger for that matter).

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HeyLaughingBoy
Do you have drawings of the product? At such a small quantity, probably only
vacuum forming or machining will be cost effective. eMachineShop might be
worth looking into, or canvass the Web for a hobby machinist with a CNC mill
that will do them for cheap.

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cmars232
Maybe one of those online fabrication sites (don't know of any off the top of
my head, but you could find some on fabbaloo.com)? Or are they still too
expensive?

Too bad you don't need more than 10-20, then you could probably use a factory
in China.

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mhb
Depends on the surface finish you want, amount of post-fabrication hand work
you want to do, price, strength, size...

You could look at www.shapeways.com

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ken
For that size order, something like emachineshop.com might be the ticket.

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madaerodog
consider this <http://harkopen.com/projects/reprap>

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mah
stereolithography

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naish
Stereolithography is usually fine for evaluating product form, but the cured
polymers aren't (usually) functional. Fused deposition systems (from
Stratasys) produce functional parts from ABS, similar in strength and
workability (for drilling/tapping holes, finishing surfaces, etc.) to
injection molded parts.

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kingkongrevenge
Look up "tool and die" in the yellow pages.

