problem with the motor

Nemanja Vujkovic · Post by **Nemanja Vujkovic** » Tue, May 29 2007, 9:04AM

I was cutting some plywood at 480 ipm, and in the middle of the cut the spindel motor stoped while the machine still moved to finish the cut and the bit snaped.
Is this something that happenes often, or is this a problem that needs imidiate attention?

Forrest Chapman · Post by **Forrest Chapman** » Tue, May 29 2007, 10:41AM

Nemanja,

What size bit? How many rpm's? What thickness plywood?

Forrest

Nemanja Vujkovic · Post by **Nemanja Vujkovic** » Tue, May 29 2007, 11:07AM

Forrest

3/8\" vortex three flut compresion bit at 18000 rpm cutting 3/4\" plywood

Forrest Chapman · Post by **Forrest Chapman** » Tue, May 29 2007, 11:50AM

If anything your running to slow which may have caused your bit to overheat and break. You said you heard the motor bog down and stop before breaking the bit. Did the motor start back immediatly after breaking the bit or did the control emergency stop?

Forrest

Nemanja Vujkovic · Post by **Nemanja Vujkovic** » Tue, May 29 2007, 11:57AM

Forrest

yes, it got the rpm's up as soon as the bit broke, and then i put the CNC to E-Stop

Forrest Chapman · Post by **Forrest Chapman** » Tue, May 29 2007, 1:05PM

Its possible your bits are dulling quickly and bogging down. Are your bits turning black?

Forrest

Nemanja Vujkovic · Post by **Nemanja Vujkovic** » Tue, May 29 2007, 2:53PM

not realy
there is few that i burned, but not the one that broke

Forrest Chapman · Post by **Forrest Chapman** » Tue, May 29 2007, 3:18PM

For 3/4\" import chinese or domestic core you should be running 750 to 850 ipm. Maybe faster considering your using a 3 flute bit. Baltic birch is harder and you may need to slow down for it. You should get longer bit life (maybe 100 sheets of cab parts) and will know when the bit is getting dull from how it sounds. If any of your bits are turning black that is an obvious sign of running to slow. This could increasingly dull and heat the bit to the point of breaking it. I hope this is your only problem.

Forrest

Nemanja Vujkovic · Post by **Nemanja Vujkovic** » Wed, May 30 2007, 8:05AM

Thank You Forrest, I will certainly try to increase ipm's today!!!