[cncsdr]

can you engrave on carbon fiber with and endmill and does anyone know if it looks good?

[greybeard]

The only carbon fibre I've used, which were pre-impregnated sheets laminated together, had an attractive "trellis-work" pattern - like cross hatching. This, pleasing in itself, might make reading your engraving a bit difficult.
I suppose it would depend on the scale of the work compared with the size of the sheet pattern.
John
PS I found it an incredibly abrasive material on the tool edges. Mind you, I was using a 9 thou piercing saw blade with 100 teeth to the inch.

[NC Cams]

We used carbide to hand machine laminated graphite R/C car chassis and, we too, found the stuff to be incredibly hard on tools.

We started using sanpaper "tootsie" rolls to do the work as it was ultimately cheaper for our needs - trouble is, the graphite would cut the daylights out of the rolls and thus size control had to be constantly adjusted by "eye". You could hardly use "tootsie rolls" in CNC.

Perhaps diamond or some other "super" abrasive would be the way to go - or water jet.....

[warpedmephisto]

Another idea - If you're just looking to do surface engraving you could use a thin layer of clear material (epoxy, acrylic, etc.) over the top of the carbon fiber and actually engrave into that instead of the woven cloth. This would retain the neat woven look of the cloth without actually cutting into it and would still have the engraved look on the surface. Since you're making a shallow cut the layer would only have to be 5-10 thou thick. Just an idea if you're worried about tooling or fraying.