I use standard end mills for cutting carbon fibre sheets. Generally the cutters are 2 to 3 mm diameter, with a flute length of about 8 mm. I use 3- and 4-flute end mills. These work quite well if they are surfaced (TiN) or solid carbide. Uncoated or HSS tooling becomes dull very quickly.

Now I need to work with an aramid composite, where the core is carbon fibre and the outer layers are Kevlar. Overall thickness is 2.5 to 5.0 mm.

The surface layers are not cutting cleanly - leaving a fine fuzz that is a pain to remove.

The cutter is cooled by airjet, spindle speed is at the maximum setting of 10,000 RPM. I have tried feed rates from 5 mm/sec to 25 mm/sec at various cutting depths without any significant improvement.

How could I improve the quality of the cut? I would like to try alternative types of cutters or machining strategies.

  • $\begingroup$ One suggestion : experiment with abrasive - such as wet sanding with carborundum "wet and dry" paper to find a faster way to remove the fuzz. $\endgroup$ Feb 17 '17 at 21:24
  • $\begingroup$ Thank you Brian. For some situations an abrasive would be appropriate. With very intricate shapes it is unfortunately not an option, particularly where the surface finish must be protected. Aramid fibre is surprisingly resilient to emery cloth! $\endgroup$ Feb 17 '17 at 21:52
  • $\begingroup$ Have you tried a propane or MAPP torch for destroying the fuzz? Don't linger more than half a second in one spot. $\endgroup$ Feb 18 '17 at 7:12
  • $\begingroup$ or brush it with a hot tip soldering gun if they are few in number. Ceramic cutters can make holes in aramid cloth, so pre-cutting is an option. $\endgroup$
    – Narasimham
    Feb 18 '17 at 19:44
  • $\begingroup$ Buffing with some polishing compound (= abrasive) might be better than emery cloth on intricate shapes, if you can find the right pressure/speed/compound. $\endgroup$ Feb 18 '17 at 21:59

I would suggest trying a diamond-coated end mill. We use those to mill graphite and carbon-fiber products at my job.


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