Success! It seems cutting carbon fiber is sort of hard to find specific information on. After just diving in and cutting it this weekend I can see it is not too bad. For this project I used 1mm bit and 2.4mm bit. Both at a 7mm/sec feed rate in my Dewalt 611. The 2.4mm bit could have been stepped up much higher.
Bits used: http://www.ebay.com/itm/381334240189?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
I wore a dust mask and followed bit with vacuum. Still waiting on my dust shoe.
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First step in my process is CNC some hold down holes that I can run some screws through just outside or in between my project. Used a 2.4mm Bit.
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Cut out any parts that need fine detail with a 1mm bit. GO VERY SLOW. I snapped 4 -1mm bits trying to find the correct feed rate without any of those fancy calculators you guys seem to preach lol.
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Load the 2.4mm bit back in and go to town on the rest of it.
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Nice. CF can be a pain or a pleasure to cut and never seems to be the same each time. 
If you want to cut CF fast look at small abrasive bits rather than milling bits. E.g. Some of the cheap diamond encrusted cutting bits can be pushed through CF very quickly and leaves a very clean finish. Obviously the dust gets everywhere and is really bad for you.
Cheers
Ian
@IanWatkins You wouldn’t happen to have a link to said bits would you? Sounds very similar to the ones I posted.
Sure thing Will.
The ones I used for cutting CF frame parts for a hexacopter which worked really well were the ones by Perma-Grit. E.g. I actually used these ones but there are bigger ones too: http://www.permagrit.com/product.php?cPath=67_84&products_id=314 and Perma Grit Rotary Rod Fine Grit 4mm RF-6F
I found the coarse one didn’t really make a much worse finish than the fine one and could cut fairly quick (I don’t have my notes to hand but it was a sensible cutting speed).
The diamond encrusted ones I mean, are really cheap and cheerful and can bought for pennies for a set of 20 or 30 different shapes, E.g. from eBay here in the UK: http://www.ebay.co.uk/itm/351255169133
They are rubbish for most things but they cut through CF and other composites very well. I’ve used them to “engrave” CF, cut small designs in CF and FR4 and do to do roughing cuts in CF, FR4 and G10. If they break, throw in the bin and forget about it.
The diamond burrs you link to are of course, just a diamond style burr but still carbide. Because you are trying to push these “breakers” through CF and pretty much only cutting the binder, you really do need to cut stupidly slowly with them. I’m actually surprised you managed to get anywhere with the 1mm ones as I think they would bind up pretty easily and break which is probably what happened to you.
Cheers
Ian
Thank you. I will check these out. If anyone has any more tips I would greatly appreciate it.
Nice Work!
Seconding what @IanWatkins said, the dust from CF is super bad for you. As a tip: some have found milling the CF while submerged in shallow water solves the issue. Double sided tape to the bottom of a shallow tray of water.
I’m all set to try this under water method tonight. I’m not sure which rates I should use but I was thinking something close to the aluminum settings in Easel. Any thoughts?
Post a picture of your under water setup!
Cool
My first thoughts are that you make sure the surface to be milled and the waste surface underneath it are true and co planar to the travel of your gantry/tool head.
As far as feeds and speeds are concerned I would go shallow on the DOC and reasonably slow on the feed rate. Possibly start off tweeting it more like aluminum and then ramping up as you go. One thing to take into consideration is how you are securing your material and not to push so hard that the material comes loose.
Controlling milling dust is a great idea no-matter the material!! However, I was not able to find any study which confirmed that carbon fiber dust was particularly toxic or damaging. Do you know of some literature on the actual health risks of exposure?
Thanks!
I think if I were cutting CF a lot then I’d want to be pretty sure the dust isn’t getting into the air. Mainly because of lung disease.
There are other links to studies, but this one from OSHA probably covers the topic as well as others:
https://www.osha.gov/dts/osta/otm/otm_iii/otm_iii_1.html#6
An under water bath would be great for counting harmful CF dust, and I think it would be great for aluminum because it would help with cooling the bit and keep it from clogging
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There are a few videos posted where they mill out a pocket in MDF, crazy glue the metal in place, then fill the pocket with oil so the metal is in a oil bath for the whole carve.
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