Z axis is binding

lasershark1
Posts: 143
Joined: Sun Apr 22, 2012 1:52 am

Re: Z axis is binding

Post by lasershark1 » Fri Jun 29, 2012 1:58 pm

As it turns out, thats not my issue at all. The motor does the same thing when it's not mounted in the Shapeoko. Does it with a different driver. Does it with a DIFFERENT MOTOR.

Must be something on the shield itself. Can a bad capacitor cause that? I'm going to resolder everything on the Z axis part tonight - should I replace the caps?

drs29
Posts: 13
Joined: Sun Jul 01, 2012 2:54 am
Location: Newmarket, ON

Re: Z axis is binding

Post by drs29 » Sun Jul 01, 2012 10:59 pm

I had a similar issue with my Z-AXIS, and originally thought it was the motor. I swapped it with the X-AXIS motor, and the problem persisted.

Turns out, I just needed to mess with the trim POT on the gbrlshield that is between the RESET switch and the power connector. I made small adjustments, then suddenly the Z-AXIS started working perfectly!
ShapeOko #457: 4040 X-axis + OpenRail + Metal V-Wheels, Dual Y motors, ACME Z upgrade, Open end plates + Inverted belts.

Colecago
Posts: 136
Joined: Fri Jun 08, 2012 5:31 pm

Re: Z axis is binding

Post by Colecago » Sun Jul 01, 2012 11:29 pm

drs29 wrote:I had a similar issue with my Z-AXIS, and originally thought it was the motor. I swapped it with the X-AXIS motor, and the problem persisted.

Turns out, I just needed to mess with the trim POT on the gbrlshield that is between the RESET switch and the power connector. I made small adjustments, then suddenly the Z-AXIS started working perfectly!
So is this a current limit issue most likely?

lasershark1
Posts: 143
Joined: Sun Apr 22, 2012 1:52 am

Re: Z axis is binding

Post by lasershark1 » Mon Jul 02, 2012 12:24 am

I believe it is. If the pot is turned too high, it pumps too much power into the motor causing it to, in technical terms, "freak out" and not turn til the power reduces.

Turn the pot down, it'll fix it.

rowblue
Posts: 12
Joined: Wed Jun 13, 2012 3:06 pm
Location: Oak Forest, IL

Re: Z axis is binding

Post by rowblue » Sun Jul 08, 2012 5:04 am

I literally just put all my ShapeOko stuff away out of frustration with this exact problem. It looks and sounds like it's binding and the motor is just screaming. I will try turning down the current and report back in the morning. Hopefully we can save some more folks from this problem.

rowblue
Posts: 12
Joined: Wed Jun 13, 2012 3:06 pm
Location: Oak Forest, IL

Re: Z axis is binding

Post by rowblue » Sun Jul 08, 2012 3:23 pm

Ok, turning down the current helped for sure. Probably solved 90% of the no-step on the z-axis. Still it seems like there is a speed limit on the z axis. Doesn't look like it can go much faster than 700mm/min after that I get the same symptom (i.e. screaming motor). I can probably live with that as long as it continues to step reliably.

lasershark1
Posts: 143
Joined: Sun Apr 22, 2012 1:52 am

Re: Z axis is binding

Post by lasershark1 » Sun Jul 08, 2012 4:14 pm

Thtas true because the Z has to turn a LOT faster to get the speed, given the 1.25mm pitch on the screw. Youd have to turn blazingly fast to get a better speed.

That being said, why would you ever need Z to move that quickly? It's X and Y that need to be able to scan fast.

thomashl
Posts: 1
Joined: Mon Jul 09, 2012 3:35 am

Re: Z axis is binding

Post by thomashl » Mon Jul 09, 2012 3:39 am

For what it's worth, I had the exact same problem and spent the afternoon pulling my hair out to no avail until I read this post. Turning the pot fixed it. Thanks.

FabricatorCraig
Posts: 58
Joined: Fri Jul 27, 2012 3:17 am

Re: Z axis is binding

Post by FabricatorCraig » Fri Jul 27, 2012 3:25 am

lasershark1 wrote: First, I made a new mount for the Z-axis motor. Mine was not lined up right - when the allthread was in the bearing, you could see the coupler bending - the hole for the bearing was not centered right. So I made a new one (laser cut wood) and that solved THAT problem (coupler was straight once all mounted).
So, did you (or anyone else) fully resolve this problem? I am running into this exact same issue... after much tweaking and troubleshooting, I am not much closer to a reliable Z-axis nor an operational machine because of that axis. Would you mind sharing the design files for the alternate motor/bearing plate so I can give that a whirl? I can certainly recreate it from scratch, but if you've already got something that is dialed in and helps.... :-)

Thanks!

-craig
-----------------Craig The Fabricator-----------------
SO1 - (1) Red Powder-Coat & (1) Non-Painted Steel
SO2 - (2) w/ lots of I.C. & other upgrades
SO3 - Serial #447

lasershark1
Posts: 143
Joined: Sun Apr 22, 2012 1:52 am

Re: Z axis is binding

Post by lasershark1 » Fri Jul 27, 2012 1:45 pm

FabricatorCraig wrote:
lasershark1 wrote: First, I made a new mount for the Z-axis motor. Mine was not lined up right - when the allthread was in the bearing, you could see the coupler bending - the hole for the bearing was not centered right. So I made a new one (laser cut wood) and that solved THAT problem (coupler was straight once all mounted).
So, did you (or anyone else) fully resolve this problem? I am running into this exact same issue... after much tweaking and troubleshooting, I am not much closer to a reliable Z-axis nor an operational machine because of that axis. Would you mind sharing the design files for the alternate motor/bearing plate so I can give that a whirl? I can certainly recreate it from scratch, but if you've already got something that is dialed in and helps.... :-)

Thanks!

-craig
Its not an alternate plate, just one thats slightly adjusted as mine was a little off - I gotta see if I saved it, thing is tho, do you have a laser to cut it?

The pot was 100% absolutely positively my problem. I turned it down some (measuring the level with my multimeter) and it stopped the problem instantly.

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