Finish on soft plastics

[Dean jeffery]

I'm going to order a 3mm cutter that's the max size without tool change, then see how it pans out.

But the main problem was with nylon and that's only 2mm thick.

Yes we are talking soft materials here and taking .1 off in plastic with a dull cutter is not the technique one should use.

When cutting soft plastics the cutter needs to be razor sharp.

[A_Camera]

I'm going to order a 3mm cutter that's the max size without tool change, then see how it pans out.

But the main problem was with nylon and that's only 2mm thick.

Yes we are talking soft materials here and taking .1 off in plastic with a dull cutter is not the technique one should use.

When cutting soft plastics the cutter needs to be razor sharp.

Yes, of course razor sharp cutter is is the best and I did not mean using a dull cutter. OK, the definition of "dull" is difficult, but my definition is if I cannot feel the edges then it is dull and won't usi that cutter any more, no matter if it is soft/hard/thin or thick material which I want to cut.

Another thing I am doing and which also reduces deflection and vibration is that I try to use cutters with considerably larger shafts than the cutter itself. I found it especially important for cutters below 3mm diameter. My spindle is ER11 so I am using 6mm shaft as much as possible. Perhaps it is just my imagination, but I think it improves the quality.

When it comes to 2mm nylon, I really don't know. Never tried that thin, but I think the biggest challenge is the fixture. How do you do it? Do you have a vacuum table? Personally I'd use some sort of glue or double sided tape, because I don't have a vacuum table, and I think it is important that the sheet is fixed and prevented from deflection, flexing or vibrating. So it is not just the cutter, even material flexing can cause the same issues.

[Dean jeffery]

Now that's a good point the cutter shank diameter, I will make sure I try and get at lest 6mm.

I use DS tape for everything I cut and if needed also add bolts, bolts added when cutting carbon or alloy.

I still only use tape when machining .3-.4 carbon but then I only use .6-.8 dia cutters.

The DS tape works really well and can be difficult to remove parts once machined, no that's not saying they don't move that's why bolts was added to thicker carbon and alloy.