Tooling for machining fibreglass

[Lugy]

Hi, we've got a large order of fibreglass parts to machine. We get the parts cut to size +1mm on all dimensions so it's not a lot of material we are removing.
At the moment we have started to use a 3 flute 20mm carbide slot drill with an FT314 coating from http://www.fenntool.com/ but are finding they aren't lasting long at all. We are getting around 70 parts to a cutter which obviously isn't very cost effective, especially when we will have around 1000 parts.

Can anyone suggest something better suited to the job?

Cheers

[Geof]

Fiberglas is very abrasive and will eat carbide quickly. Using moderate rpm with a good feed can prolong cutter life but sometimes it gives a poor finish.

If you can switch to an insert cutter you may be able to get better life with ceramic inserts or try PCD coated carbide tools. These are more expensive than regular carbide so overall you may get better tool life but the total cost may not be less.