Engraving Plastic

[german]

Hi guys, I need some advice in what bit to use; I want to pocket some text like about 1/4 inch hight, 1/8 between vectors and 1/16 deep on plastic, and the text bottom must be flat,I have been loking around with no luck, any clue will be appreciated.
thanks in advanced.

German.

[ryan_slaback]

German,
I have been engraving signs for my school with a 1/16" bit in plastic. I will look at my speeds for sure when I get back to school, but there are a couple things I can tell you.

1. SLOW router speed or the plastic melts and sticks in the bit.

2. Rip off the protective plastic before you machine it. I had issues with the covering getting stuck on the router bit and causing it to stick chips and melt the plastic.

[wayne_walker]

German,

Ryan is right on - Low RPM and cut a little faster. I cut ABS at 10,000 RPM (router) and 2.5 IPS with a 3/8" 2 flute straight bit and blow air on it. I don't cut very aggressive only .125" deep. This combination has worked well for me. I do a clean up pass at full depth. The air helps a lot.

Wayne

[paco]

If you don't want end mill type bit; tipped off (say 0.02-0.04") engraving bit. No true point.

[german]

Thank you guys for all the information you send me, I will try that as soon as I can.
Ryan, did you use a regular end mill bit or ball end bit?
Paco, you mean make a ball end out a end mill bit?
Thank you egain.

German.

[ryan_slaback]

German, I used a regular end mill type bit. This one to be exact: http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/bit_straight.html

[paco]

No, I meant to use an engraving bit (http://www.oracal.md/oracal-eng/reklama/img/engravingbitsetforsteel2.jpg) instead of an end mill type. You didn't mentioned in your first post so I thought it was worth to mention since engraving bit are intend to engrave. Small ball end could give a nice result also...