Thanks for the advice, tool manufacturer said the slow speed is down to heat, if there is too much heat build up then instead of cutting the flute clogs, putting extra pressure on the axis motors as the fluted are no longer cutting, then stall detect turns motors off.. So lower rpm , 7-10,000 rpm can keep tool cooler, and avoid resin melting if that's the problem.basically he said its entirety dependent on the exact property of the carbon resin.