Plastic engraving....melts/loads up bit

[baltic_birch]

Material:
http://www.inoplas.com/products/interior/primaryplus.asp

1/16 thick black w/ white interior


Bit:

http://www1.mscdirect.com/CGI/NNSRIT?PMAKA=60058609


I can do small text ok.

Problem is with any lines more than an inch long.

It basically starts to melt a ball on the end of the bit and then engraving goes downhill.

I set my router at 1 ips and rpm at 12k.
I'm engraving 10 mils depth.

What settings should I be using to stop the melting? Faster or slower move speed? Change RPM?

Thanks!!!!!!!!!!!!!

Andrew

[GlenP]

I have watched a engraving shop do some glass once and they had to constantly spray a liquid (looked like window glass cleaner) on the glass. What about some sort of cooling for the bit. Maybe go talk to a local engraving shop and ask them, their machines are much smaller but who knows maybe if you get it working they would hire you for larger jobs they have been turning away.
Good Luck

[br928]

Move faster and/or slower RPMs. The bit is to hot and the chips are not taking the heat away. If this is standard engraving plastic then you may want to purchase engraving bits for this purpose. I buy mine here, http://www.artisan-es.com/. I also have an engraving machine. I have succesfully used end mills with this type material too.

[Brady Watson]

Make yourself an airgun for under $20:

http://www.bradywatson.com/Aluminum.htm

It's nothing more than a scrap piece of MDO cut to fit the spindle, some all thread, a Husky brand blow gun kit with football inflator and a few brass 90s and close nipples.

-B