Hi

I'm doing a university project and I am required to make some food safe moulds for chocolate, the aim is to keep the cost as low as possible, the best way to do this as much as I know is to use a smooth solid material and a cnc milling machine to carve the design that I want and use vacuum forming to make a food safe mould out of it. the reason that I said smooth and solid is that it would hold us nicely for the vacuum forming machine to do it's thing. now my only issue is that I don't know what the cheapest material that I can use would be, some one recommended plexiglass but I don't think working with it would be easy and I'm pretty sure I would be able to find cheaper material as well, any help would be greatly appreciated

Regards
Parham