Z problem

[dan78]

Hi guys,

I have Shopbot Standard 20212 , and few weeks back , I start having hard to understand and pin point problems with the "Z" . Initially I was suspecting "statics" , so I eliminate "grounding" problem , to make sure are not the statics what makes my Z to go uncontrolled.
Anyway long story short , Z is not lessening, it is going down less few mm than should go , occasionally out of the blue go up , even when I try to "Z0" soma time , fails , Z going in the routine up. Same times when lives 0,0 (Z, Y) point , makes a few mm up then go , and obvious , never recover Z position again. Lots of debugging is already done...try to see if any similar frustrating experience, and some idea , where to start to narrow , seems like , everything I have to do from this point is going to cost. Hope to spend correct. Thank you for your time. Regards DAN

[ken_rychlik]

shopbot tech support is a free phone call or email away. That said, I would remove the motor and see how smooth, tight, loose, the z moves up and down by hand without the motor. Eliminate the mechanical aspect first. Look at the gear wear and how tight the gear is on the motor. That will be free and help you narrow down the problem.

[dan78]

Thank you, I send them an email so I can touch base with them. I have removed the motor, and z was moving smoothly, release one bearing and slow start coming down, was steady with both bearings. Install control software 3.8 no change, I actually feel is worse. Rolled back control 3.6 and can cut max 3 profile ok, then z go the way wants, I can fell when start failing, occasionally makes a bit of up tic before is placed on cutting position, where fails , is not going deep how should go, or even worse is going up. Try to see if anyone have something similar, and what was the path to find the problem. On this stage....I am afraid I need to look after a new motor.

[ken_rychlik]

That tick noise is the stepper motor loosing steps probably. You may can change the settings to slow down the z rapid movements and that might be enough to get it going. Check wiring connections from the controller all the way to the motor. The most common thing to fail is a driver. You should have at least 4 drivers allowing you to be able to swap drivers and see if that helps. Naturally all of this swapping is done with the power off and unplugged.

[dan78]

Thank you, on this stage I have the Z movements, set up default after a fresh installation of the control software, I will try to reduce by 1/2, to see what is happening, thank you for the idea.
Regards Dan

[bill.young]

Along with lowering the cutting speed, try reducing the Z-axis Jog speed as well in the ShopBot software. You could be losing steps during the jog moves when it first lifts and plunges?