[kevinro]

I am starting to have issues with my PCNC 1100. Seems to be lacking power at times. Specifically:

1/4" Carbide 3 flute mill doing slot clearing from Fusion 360.
.375 DOC
.0400 WOC
5100 RPM
32 in/min

Chip load is .0021

According to GWizard, should require .0918hp, which doesn't seem like a lot. The motor faults and shuts off. The fault light blinks then goes out.

Q1: Anyone else see behavior like this?
Q2: When the motor faults, the mill keeps running the program with the X/Y/Z which seems like a bad idea.

I have also seen the motor bog down during a deep drilling operation with full retract using a 1/8" drill bit in aluminum. I am doing .0625 pecks and a full retract. That seems gutless to me.

Kevin

[oneineight]

Does it do that with new sharp tools?

[kevinro]

Does it do that with new sharp tools?

Unfortunately, yes! I thought of that to and grabbed out a brand new drill bit (screw length, decent quality) and carbide endmill never used before. I just switched to a Lakeshore Carbide variable flute and had better results by doing a .25 DOC. Still, this shouldn't be enough load to stop the machine, especially with a 1/8" twist drill bit.

[popspipes]

I am starting to have issues with my PCNC 1100. Seems to be lacking power at times. Specifically:

1/4" Carbide 3 flute mill doing slot clearing from Fusion 360.
.375 DOC
.0400 WOC
5100 RPM
32 in/min

Chip load is .0021

According to GWizard, should require .0918hp, which doesn't seem like a lot. The motor faults and shuts off. The fault light blinks then goes out.

Q1: Anyone else see behavior like this?
Q2: When the motor faults, the mill keeps running the program with the X/Y/Z which seems like a bad idea.

I have also seen the motor bog down during a deep drilling operation with full retract using a 1/8" drill bit in aluminum. I am doing .0625 pecks and a full retract. That seems gutless to me.

Kevin

Maybe check for loose power connections? It doesnt sound like too much load, spindle /motor bearings if the problem is intermittent.

[Uman]

Take a good look at the VFD in the control cabinet and the associated electrical connections. Verify VFD input power volts and use a clamp on amp meter to measure input current. There are some posts with pics related to VFD/spindle calibration that will help you get familiar with it.

[CadRhino]

Have you gone over the belt/tensioning? Have you tried changing belts/position?

Take a good look at the VFD in the control cabinet and the associated electrical connections. Verify VFD input power volts and use a clamp on amp meter to measure input current. There are some posts with pics related to VFD/spindle calibration that will help you get familiar with it.

[oneineight]

Like popspipes and UMAN say, I would be checking for loose connections and input power voltage.
It could be low voltage on just one leg of your power.

[keen]

And the spindle turns by hand freely?

Keen

[tmarks11]

If the VFD is shutting the motor down due to load, it should give you an "OVL.d" error on the VFD display.

No errors on the VFD? Just the VFD shutting off completely? Not an overload condition. VFD doesn't power itself off in that condition.

The spindle door microswitch will make that happen if it is a bit loose. Maybe it is vibrating under load. Also (as others suggested), a lose power connection to the VFD or lose control wiring on the VFD could do that.

Does it sound like the motor is noggin down and slowing just before the trip?

[R.DesJardin]

If the VFD is shutting the motor down due to load, it should give you an "OVL.d" error on the VFD display.

No errors on the VFD? Just the VFD shutting off completely? Not an overload condition. VFD doesn't power itself off in that condition.

The spindle door microswitch will make that happen if it is a bit loose. Maybe it is vibrating under load. Also (as others suggested), a lose power connection to the VFD or lose control wiring on the VFD could do that.

Does it sound like the motor is noggin down and slowing just before the trip?

What year and model of machine? Motor door switch, you'll notice the motor slow because it's been tripped off by the switch. The axis does keep moving. My Series 2 did this a couple times til I changed the door switch latch. It was before the current latch design. As always check all the connections, I try to do this yearly. Just use a screwdriver to verify nothing is loosened.