Need Advise Cutting ABS Plastic (please)

[tuck]

Hi guys. I have a job to do cutting letters out of 1/4" ABS plastic. I've not cut it before and have heard somewhere that the chips will re-weld (melt) if the cutting speed is too fast or slow and if the bit is spinning too fast or slow. I'm wondering if anyone in here has experience cutting ABS and can give me some tips.

Many Thanks!

[superior]

Mark: Go to Onsrud's website and look around. They have a complete guide line to follow, with all the cutting info you will need. Sorry, I don't have the site in front of me.
Doug

[tuck]

Ok, will do. Thanks, Doug.

[neal@lasertechalaska.com]

I've used 1/4" Spiral O's with good success. Run a test to determine cut speed/RPM. Spiral o's are a micrograin single flute up spiral with a special grind for plastics. I've used them cutting UHMW also.

[tuck]

Thanks, NSchlee. I appreciate that advice. ;-)

[tuck]

Gotcha, NSchlee. Many thanks!

[kerrazy]

Mark,
Onsrud offers feed and speeds for there bits as well. reduce those based on what your tool will do.
For example if you have a PRT you really can only cut 1.5 in/sec. so if they say a feed of 150 in/min and 18000 RPM and you run in inches per second divide the 150 by 60 and you will get 2.5 in/sec. . Your tool will not run that quick with out edge chatter in the parts So that being said reduce your speed to 1 in/sec and reduce your RPM to 7200 if you have a spindle or 10,000 (the lowest possible in a PC router). This will reduce your chances of rewelding to itself.

Onsrud designs its cutters for big CNC's so we have to take there info and scale it back for use on a PRT.
Good luck
Dale

[tuck]

Thanks Dale. Does it help to spray water while it's cutting?

[kerrazy]

not neccesary.
Dale

[tuck]

Ok. The ABS is 1/4". Would you cut it 1 or 2 passes?

[kerrazy]

I would do it in 3 passes, using an offset of .02 for the 1st two passes and cutting only .200 deep. Then I would do a clean up pass for the final thickness on the original part.

Dale

[tuck]

You da man, Dale! ;-)

[earld]

Dale,
Have you noticed a difference in finish with climb cuts or conventional cuts? I was getting a cleaner finish conventional cutting- less welding of chips.
Earl

[kerrazy]

My software does a conventional and then cuts the last pass climb. As I am taking off such a small amount, I get a reasonable edge.

[charles_o]

follow the links for info on routing plastics

http://www.plasticrouting.com/BitSearch.asp?Page=Material
http://www.plasticrouting.com/Van.asp
http://www.onsrud.com/popChart.html