Z problem

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

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.

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.

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.

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

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?

Thank you guys.
So I have already reduced the "Z" speed to this value, and that ...makes a bit of a difference (the Z car have now one of the most carefully maintenance job I have done on it in 10 years, cleaning, oiling bearings, and grease the pinion all the way not just where I can touch , clean all the accumulated old grease, and replace with fresh grease ) I just reduce the jog speed on Z , and on top of everything I am planing a new test , what will be done when the temperature drops around 20 degrees (Celsius, during night time if is going to be necessary) or less to make sure the heat wave is not having a uncounted (or ignored) reason as well . Cut all the "statics" sources to make sure there is none , and see what is happening. Just reducing the Z speed I have a good improvement so far (still bad, but at less I am on the point where I was one week ago ) , but monitoring what Z is doing I still can notice a slow up coming , only a bit, but that is all what is needed to fail making a full cut trough. At less on last test yesterday I cut 3 surfboard ribs, previous day I was hardly making 1 cut and a bad failure was striking constantly. If the next test on this condition is not showing any improvements , what is next? Ordering a new motor ? Is the motor coming with the controller ? Any chance to have a problem with the motherboard ? I have no problem with XY, is that ok to assume the motherboard is ok ? Shopbot would mail a new engine with a "trusted motherboard" (not new) for a test if it is the case ? Obvious if I can figure out what is the problem, I would not hesitate to "fix/replace" the faulty (if there is a faulty) piece/elements. May prove to be a settings problem on the controller. (hoping for the best)

Hi guys,

Please do not ignore us, we need help to fix the problem.

After we post the same details on the forum, we think the z settings where to aggressive, and we try to reduce the values to see what is going to happen.

We clear the software , and we make a fresh install v2.6.46.

We set up the Z values to 12 for cutting and 20 for jogging.

We start testing very cautious, and we run a few test , but only 1 or 2 profiles cut on various materials , plywood, mdf and wood. All works fine on this tests.

So we plan a cutting session.

We eliminate all the source of statics , we start at 4 on night time, so was very nice and cool.

We cut about 1 hour no problem, then the problem is back.

Slowly z lose his alignment, if we have a profile to cut out with tabs, after cutting first tab the z start going up not down , and end up the program about 36mm error compared with his position 25mm (over all go up to 61mm).

At less now we can control the z with the keyboard, so we can bring the z down and 0 again.

What is next step ?

If I order a new Z motor, is coming with the driver ?

X and y works fine, visual inspection on the motherboard is not indicating any problems, do we have any reasons to suspect the motherboard as well ?

Can you send to me a "test" motherboard if the change of the engine is not fixing the problem ?

Please do not ignore my email , work with me , we need to find the problem.

Kind regards Dan

This is a user forum of normal people. This is NOT shopbot tech support. That goes through their email and 800 phone number. I suggested you switch some parts around to isolate the problem, but I don't think you did. If you switch a z motor with a x motor, that will be a test to eliminate if you need a motor. The same can be done for drivers ect... I wish you luck but again this is not where you get factory support.

I will have no chance than to look on changing the motor position.
If I do that , I am going to potentially shift the problem on Y axis .
I was kind of happy because I am not losing x,y alignment and with that , so far not wasted any material , but I guess will have no chance than to do that for next step.
And sorry to spam you with a copy for the support team email, I am now on contact with them again, looks like they have lost one of my emails, and I was afraid I have lost contact with them, and this is my only help now.
Thank you for your time and suggestions it is very much appreciated . Dan

After we follow all the steps, guided by ShopBot support team , we get to the conclusion the error is with the Driver. We shifted the error on "Y"axis where is now more consistent and a lot easy to see. We have ordered and we are waiting a new Driver. I will add a new update after we replace the Driver.
Thank you to everybody who was involved.
Regards Dan