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Can anybody comment on making your own plastic pieces, whether through
casting (as in the case of acrylics) or through injection moulding?  I'd
guess that both methods would require first the making of moulds for
churning out prototypes, and then obtaining material for filling the
moulds up with?  I read somewhere that plastics injection moulding employs
little plastic pellets that are exposed to heat and liquefied, and then
pumped into the moulds.  I'd suppose that foundries specializing in
plastics could work with initial prototypes before they actually do a real
production run.
 
Since the difficulty in making pieces is the same no matter where you do
it, a more serious question to ask, is whether production expenses would
be less if products were manufactured in one part of the world as opposed
to another.
 
Where are most plastic chess pieces manufactured in the United States?

Are there alternative sources for plastic pieces than the US?