[cadop]

I have found tons of information where people want to make a cnc positive and create a silicone mold. I am trying to find a way to directly CNC the silicone. I have a sheet of silicone 10mm thick x 50x50mm.

What is the best bit for cutting this type of material?

[bhurts]

You will most likely never get acceptable results regardless of the bit you use. It is no good trying to cut something that deflects severely. You can try freezing it before cutting but to work it would need to be a very short cycle time. As for making a positive to create a mold. That is really the best method since when the mold wears out making a new on is very easy.

Ben

[cadop]

The freezing idea is interesting. I am actually doing this in a research lab. We make things similar to silicone and sometimes silicon with different types of embedded components. So there is a reason for not just making a positive in a different material.

We do have access to plenty of liquid nitrogen, im thinking it may be possible to setup a rig to continually cool the material.

[awerby]

The other problem you're going to have is holding onto it while you're trying to machine it. Nothing sticks to silicone rubber very well (with the possible exception of more silicone rubber) so most adhesives won't work, and it's too floppy to hold in a vise or with strap clamps. A vacuum pod is probably your best bet; that plus the liquid nitrogen could possibly combine to be a machining solution.