z-axis trouble?

I’ve taken some pictures of a problem I’m having on one of four (4) TAZ 5 printers we use. It appears that the something is wrong with the z-axis as the parts looked very elongated. I’ve printed an individual part out just fine. The pictures show one of thirty parts that were printed all at once on the printer. This part has been printed many, many times successfully on this printer and the other three.

From looking at the pictures can anyone suggest a likely area to investigate to resolve this issue?


Check inside the control box and see if the heat sync that was on the Z axis motor driver is still attached, and that the control box fan is operating correctly. The only other thing I know that would cause that is if the Z steps value changed inadvertently via a firmware update or a LCD panel change

Thanks for your response. Any chance you could post a picture of what your describing?

It’s the heat sink shown in the pictures under here: https://ohai.lulzbot.com/project/c8d1632e-5df4-4844-8f4f-e653379a8fc3/a16b1f2d-5c1f-47fe-a83d-9d68cca5d62c/

The little alluminum thingy with fins on it.

Thank you for your help. My issue was a heat problem as you suggested but it was due to the enclosure temperature being too high such that benefit of the heat sink was not realized (my theory anyhow). Solution was to simply open the enclosure door during printing and let the temperature remain relatively low and also not be able to build up high enough to cause precise loss of the z axis control.

thanks for your prompt reply and for helping us zero in on the area to look at!

My Taz5 has Z-axis inconsistencies - I opened the control box. Reseated the two motor connectors, but noticed there is no heat sink on the Z controller. It’s not floating around in the box, was it always included? Should I get one?

I’m new to this community even though I’ve had my TAZ5 for many years. Am surprised at the reoccurring theme of Z-axis issues. I believe I just responded to you or someone with same issue under different category. Because the Z-travel is a very light duty cycle, I doubt that there is much heat generated in the controller. Unless you power UP the Z-axis for a long distance I don’t think heat or the need for a heat sink is much of an issue. Most long Z-axis stroking is for tall prints when the print head returns to home under weight of the gantry, an easy duty cycle. I suspect misalignment and over-constraint between your chassis and gantry which is causing your ball screw to bind. See the attached. I tried to attach a pdf but only images allowed. Good luck.
Dave O

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