Poly-carbonate......best way to engrave

I am trying to engrave a large piece of poly for a friend. It’s not going so well. It is just a line image at .005-.01 deep. I was trying to run it last night at 50 IPM and the Dewalt 611 at between 1 and 2 and I am getting the melt after a few lines. I am using a 60 deg 6 flute v mill, TIA

6 Flute V bit?? I didn’t even know such a thing existed. Try using much fewer flutes, Jay. Like one of these maybe?

He may be using these bits (or something similar) from Dremel - https://www.dremel.com/en-us/Accessories/Pages/ProductDetail.aspx?pid=125

actually just took another look it is technically a carbide bur…I have a fair amount of misc tooling laying around…maybe I should try my 1/4 90 degree drill mill or a 60 degree center drill

On plastic, the fewer flutes, the better.

There is a thread on lexan which is a form of plastic like your doing.
He gives all the details and it may help.

Try one of these to slow your router to a low enough speed to avoid melting. http://www.harborfreight.com/router-speed-control-43060.html
It’ll give you more control, like you had a spindle with VFD.

I have it working well now with a 90 deg drill mill. The harbor frieght speed controls do not work with the dewalt 611 from what I have seen posted. I have some standard 1 flute engraving bits on the way so I expect to get even better results then. thanks

I have one of those Harbor Freight speed controllers and it does not work.
the thing will sputter.
What I did is get the dc spindle and I will be able to switch between the two depending on what I am cutting.
The spindle will go to zero and then up to 12k roughly. I do not have a tach set up to measure it.
The slower spindle allows me to cut Optiplex from Home Depot. No melting and it looks great.