Need Help!- Spindle Load Problem on CNC 88HS

[phat]

Hi Everyone,

We've had a CNC 88HS for nearly six months or so - bought at an auction - and have had intermittent issues with the spindle inconsistently losing RPM during operation making the machine unreliable. We contacted Fadal who sent out their "best guy" - he recommended an (expensive) encoder change - we did and it didn't help the issue. Whenever the spindle RPM starts to wander, the "Spindle Load" meter reports excessively high load.

This morning we turned on the machine and the "Spindle Load" meter shot up to ~90% without any spindle motion at all (see the attached photo.) I'm assuming the problem is related to our previous RPM issues.

One suggestion has been made internally (here) that perhaps we should clean up all the PCBs (ex. contacts to the back plane inside the control panel) to see if that helps resolve the problem.

Does anyone have another suggestion? Any help would be greatly appreciated.

BTW, we're located in Fremont (Bay Area.)

Thanks.

- Phat

[denmar]

CHECK THE SPINDLE ORIENT HALL EFFECT SWITCH ABOVE THE PULLEY.

[Neal]

Denmar--
FYI-- the hall switch on the magnet only tells the machine that the spindle is running or not. It does not report any relationship to RPM. That is the spindle encoder's job. The hall switch on the spindle is also used for rigid tapping.

Neal

[denmar]

.

[dominus]

Hello phat! Have you solved the problem? I think i have similiar problem here. when i activate c axis(only positioned, not rotating), there is exessive load on spindle. if i activate c axis and brake, load slowly increases, until there is overload alarm.if i press e-stop button beafore overload, spindle rotates little. it seems like it constantly wants to move.. with only c-axis activated i can rotate spindle 0,5cm left and right(it's not holding strongly it's position, but it returns to original osition).

[fadalserviceguy]

Hi - you don't mention what the Spindle Drive is and also if the Spindle has H.T> or the old 6 belt system - also if you drop air pressure during the day the belt hi/low may lose tension - another check is make sure your 3 phase input is a consant 220 vac - Dave

[PGrantz]

Hi Phat,
I would be interested in knowing who the Fadal "best guy" was. Many people claim they are Fadal service though that is not always true.
If I (the factory) have sold you a drive or service that did not fix the problem, please let me know and I will make it right.
Beyond that, what is the serial number and I can look up the build history. I can then recommend the proper resolution.

[fadalserviceguy]

phat - if the encoder did not fix it and you are sure your 3 phase is ok - the reason i asked about your spindle drive you have is because if you have a Baldor drive it sould have a keypad that can assist you with dianostics - if you have the AMC or Black Box i have seen what your describing and there are no dianostics on this drive - also it's rare but the spindle controler bd. could cause this - last since you bought the VMC at auction has any one checked the Spindle motor itself for shorts , even high meg shorts can cause intermintant problems-
fadadserviceguy

[carbidecraters]

Replace the meter and check the wiring in the pendant.