Took my 3mm thick FC plate to fablab where they have nice cnc router, wanted to cut out some arms for quadcopter frame. All went well but the router bits did not last long. I never used that sort of machine before, so i have few questions, first of what kind of bit i should use for CF ?

My preference for cutting plate is to use abrasive water jet.

Carbon fibre sheets will very quickly kill any router cutters that are not Carbide .. even TIN coated milling tools get blunted very fast .

This is precisely like milling or routing glassfibre printed circuit boards .. 

The same goes for drilling a lot of holes .. the drill has to be Tungsten .. or it will not last ..

Very high speed and sharp+hard tools !!    That is why Water-jet is very good!  It will leave nice edges (not perfect) and if you make sure to start the cut at en edge or at a point on the sheet that will not be used, it works very well.

I have invested in a few tungsten end mills for my Non-CNC milling machine to handle this sort of stuff .. 

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http://www.ebay.com/itm/Kent-10-Fishtail-3-0mm-Diameter-Carbide-Router-Bits-End-Mill-and-Engraving-Burrs-/291486224465?hash=item43ddeed051:g:emoAAOSw~OdVdGH-

you need to use a 'burr' if you in a hurry and cant wait for shipping , then use a tile cutting bit  ...

Dark matter composites have just released some good routing bits and hand held tools with extraction. I'm hoping to get some once my workshop is sorted out

I noticed this when I used to use my band saw for trimming big parts.  The blade didn't last long before it ended up with no teeth (worn away!!).  I now use a carbide tile jigsaw blade for big bits and a carbide or diamond wheel for small bits.  Anything HSS won't last long.  You can use a small carbide burr in a router / mill to cut it but the edge is a bit furry IME.  A tickle with some sand paper takes the fur off.

Does anyone think its possible to cnc rout a CF plate so it comes off the machine without the need to be finish sanded or deburred?

I use carbide burrs from WNT at various feeds and speeds but can't seem to get a perfect edge that doesn't require some kind of finishing.

The PCB cutters provide a pretty good edge although with most machining you will almost always get a sharp edge that needs  light de-burring.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

I am just starting out with a handheld router and carbide bit with good results on the test piece last night.  Edge is smooth as can be, no damage to the surface either, keep in mind the bit is brand new though.  I was testing on 6mm thick CF 

https://www.toolstoday.com/solid-carbide-carbon-graphite-and-carbon-fiber-panel-cutting-router-bits.html?variantids=12012,0&keywords=46264