Recycling PET Polymer Blocks

There are machines that are used in the molding industry to regrind thermoplastics such as PET for reuse.

I don't know if the 1.2mm requirement can be met with a single pass, though.

Google regrind machines.

Regrinding a 300mm cube would be significantly difficult.

I suspect that a better method would be found in the timber industry equipment used to produce wood chips. I imagine something like a big power plane with notched blades instead of flat.

By the way, if you're wanting to re-process the PET in a moulding machine you would like to have no "dust" smaller than 0.7mm also. That's because fine dust stops the material flowing in the hopper throat and also through the barrel of the moulding machine.

"Regrinding a 300mm cube would be significantly difficult"

I don't do well at metrics. Except for a few bullet diameters, I'm pretty much illiterate. Runners and sprues aren't nearly that big though.

You are right.

Cheers.