Taz 6 Z axis thinks it's half the height?

Hi folks,

I’ve got a weird problem with my Taz 6. The Z axis keeps defaulting it’s max height, to approximately half of what it should be. This is causing all of my prints to be squished into half of their designed height. I was advised to move the Z axis all the way up and then all the way down, followed by a factory reset. This appears to solve the problem, because I can then get the z axis to travel all the way up to it’s true height limit. However, when I send a print from Cura, the damn thing seems to forget the factory reset and compresses the print. please see the attached image of the print in it’s squished form next to the actual version of the print. In the background of the image, you’ll see the tool head at the height that it seems to think it’s maximum height is… (hopefully that makes sense). :cry:
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Did you ever get this fixed?

I really need to revive this 5yo topic because my 5yo machine is dealing with this exact issue and due to the change of ownership of Lulzbot, their support is nearly non-existent.

Is it possible that anyone else has experienced this issue and can share the solution that worked for them? I’ll break-down my experience so you can hopefully see why the previous solutions don’t seem to apply to my case.

I have a TAZ4 running the most recent version of the firmware 2014Q3. The firmware was manually selected and installed via CURA and worked great for months. While printing one cold winter night here in Colorado, I touched the frame of the printer and a small static shock caused the printer to freeze and reboot. When it rebooted, the settings for my steppers had reverted to the “stock” settings for steps. For my “Z” axis this means it set it to 1600steps. My Test/Acceptance record that came with the printer, and the setting that has been set since I got the printer has been 400steps.

I proceeded to put the settings back to what I understood to be correct, but now my machine only moves 25% of the input distance (A 10MM move yields 2.5MM of travel). Both Z motors turn in unison and at 400steps, they move smoothly with no drama. Obviously I tried increasing the steps 4X because it’s how I’d logically get back to full moment, but when set at 1600steps, the motors spin-up dramatically and lock up instantly causing all kinds of commotion and drama.

Lulzbot has been nearly 0% helpful only suggesting I re-install the firmware. Since sharing that solution was not successful, I have gotten zero response in more than 2 days.

My stepper board does not seem to be overheating. My fan is operating exactly as it should, and I have removed the cover from the board housing and am testing the Z axis movement with no heat in the nozzle or bed. There should be nothing taxing the board to the point it overheats.

Did something change in the firmware that requires the TAZ 4 to run with steppers set at 1600steps rather than the 400 listed in my Acceptance Record? Has anyone reduced the stepper ramp and speed to adjust for this and found that to be successful?

Thanks for checking out my zombie thread. I’d start another one, but this context fit so well.

Hey jtenkely,

I’m dealing with a similar issue with two of my Taz 6’s and have reached out for support as well with no response so far. The first of the two just needed regular maintenance and cleaning but my second machine z axis issue still persists. I’ve been looking for solutions for the Taz 6 as well as on other lulzbot machines since the hardware is pretty similar in many aspects.

I did see a suggestion about cleaning the pins of the Z axis connectors both at the board and axis.

It definitely isn’t an overheating issue for me, either.

While I know this is rather unhelpful for your Taz 4, I am out searching for a solution before I attempt to replace the board as a remedy (and see if even that works). This does seem to be a common problem but can be caused by any number of things. I noticed cleaning and maintenance is the most common solution with all lulzbot models, but still this problem can be a persistent one.

I’ve scoured my emails to find how I fixed this. It was so long ago I have forgotten what I did, and I must have solved it over the phone because I can’t find the email. I would try resetting the esteps or maybe try going back to an older firmware. To be honest, I’ve pretty much given up on my Taz’s. I originally bought Lulzbot machines because of the incredible support. That has pretty much dried up since they were sold. When I do use my Taz’s I’ve abandoned Cure LE, Prusa slicer now has profiles for the TAZ 6. It prints much nicer now. Maybe try that and see what happens? Sorry I couldn’t be of more help. Thanks to Covid I’ve had such little access to my Lab I feel like I’m forgetting how everything works!

After a late night of tinkering. I have actually found a resolution.

Given that I was only moving 25% of the distance, I started with trying to get to 100%. To do that I took the steps/mm back up to 16000. The issue at that point was the motors trying to spin-up so quickly that they just lock and grind. I concluded that it might be that the motors were going to full-chooch at the moment a command was sent, so I checked the V-Max speed setting in the “Motion” portion of my LCD controller. Sure enough, mine was set at 8 on a range of 1-8. I reduced the Z motor V-Max speed down to 3 and tested it. Everything worked fantastic, albeit a touch slowly. I stepped the Z motor speed back up a couple clicks to 6 and things are working exactly as I had hoped. Great quality. Quiet motors. I claim victory (and in 2020 that means you actually have to win!).

Thanks for the forum to externally process and for all the bits and nuggets people have left lying around that I was able to piece together into something… still haven’t heard back from Lulzbot. ¯_(ツ)_/¯¯

Agreed. I inherited the lulzbots coming into the makerspace and they were not regularly maintained. Immediately changed that, but also went ahead and bought a bunch of Prusas and a Fusion F410. Support for those machines has been flawless in the years I’ve been using them, while lulzbots have had a steady drop in response time until… nothing at all.

Jtenkely, I’m glad you found a solution. I may try that with my machines as well. Most of the time poking around the forums (even for different machines) has led to solutions when I am unable to reach support.

I’m glad you got your taz working! I am curious what firmware you’re running, and why you had to do this configuration manually. In solving your problem, you’ve recreated the default velocity settings for firmware configured for 1600 microsteps/rev. The question is why did you have to do this if you successfully reinstalled the firmware, which should reset the system to workable values?

When I look at stock taz 4 configs like this config this config, 400 is the default Z step config for a taz 4. From what I can tell, this changed to 1600 on the taz 5. (I own neither of these, so many grains of salt here) So 1600 doesn’t look like a default on the 4 but maybe there is a newer firmware for the 4 with this setting. But its unlikely that your eeprom settings were randomly overwritten to this value via the miracle of ESD. It sounds like maybe you experienced a mismatch between the firmware and the eeprom defaults. This can happen if the firmware is installed without rewriting the eeprom, or vice-versa. I mention this because it would be frustrating if you solved your immediate movement issues, but the underlying causal factor is still in an unresolved state. Note that M502 followed by M500 will reset eeprom setting to their default as defined in the firmware.