Machining paper covered plastic

[kaizad]

Hi,

We recently purchased a high speed router for machining plastic (acrylic, nylon, fiberglass). The parts are covered with paper for protection from scratches and has to be present when machining. The issue is that while machining with a conventional upcut endmill, the paper is not cut clean and either wraps around the cutter or then lifts off the part increasing the risk of pits, scratches etc. We did try using a downcut router bit, which cut the paper but chips did not evacuate cleanly and were re-cut resulting in all sorts of problems. I would really appreciate it if anyone has suggestions on how the paper can be cut clean and at the same time chips pose no problems. Please let me know if you need any further information too.

 

[jbel]

You could try a very light cut at high feed to get rid of the paper and then go back and cut the plastic underneath.

 

[kaizad]

jbel,

Thanks for the reply. I forgot to mention that I did take a light cut but it didn't work with an upcut endmill. A downcut router bit did work but the machine does not have a tool changer and hence we would have to change tools once the light cut is completed which again is not very efficient. Would you know of any special cutters which might work?

Thanks again.

 

[BillPSU]

You could try a reverse spiral endmill or a high spiral endmill. These are specialty tool but can be made.

 

[aamoroso]

I would suggest a 2 flute tool, very high rpm (you probably already are). We used to put clear shipping tape over polished parts to prevent chip scratch, worked well if you put it on nice and flat.

Try using Air as coolant to clear chip and burr while cutting. If you blast the air on the tool while cutting it will break away the debris.