Creating molds from 3D Printing?

[Valter]

Valter,
I have done both, if there is undercut detail in the figure you will have to go with a silicon mold pulled from a original, the reason for this is the silicon will allow you to be able to remove the part if there is alot of undercuts etc. it will stretch to be able to remove cast part. With a silicon mold you can re-use it many times and its pretty durable compared to a hard printed mold. If it is a simple (example hollow easter bunny) that has little detail like arms etc. you could print the mold, but with a printed mold it is rigid and have to think ahead on getting part out.
check out http://alumilite.com for some great mold tutorials.
the process is really dependent on the figure and end use. I have a model of a infants head from a customer that makes dolls, to cast this solid is not really feasible since the end product would weight around 5 pounds. so in this case my rotational casting machine fits perfectly to cast hollow parts. now the head weights ounces instead of pounds and functions perfectly for its intended use.

in short you should print the original vapor smooth or post process it however to get want you want and make a silicon mold of it.

Thank you very much.

My 3D models (most them) are complex. So I'm thinking that a silicon mold will be the only way to get a good copy. navkram, just for curiosity. How many copies your silicon mold support with a sculpture with 20 cm tall? Polyester, polyurethane, vynilester Resin?
Thanks again. Excuse my english.