Geeetech

anyone else having issues with random skipping of z-steps?
My A30 skips raising the z axis at random during prints. I have adjusted the VREF for the z axis up to 1.15v as suggested. also oiled the screws and made sure that the z-axis moves freely and does not bind. I still get the occasional missed z axis move.

Is there a printer in this price range that actually works?

Hi


You have practically applied all the most important adjustments.

I would also check the distance between the transverse beam ( on the right and left side) and the drives.
It must be even. Otherwise the mechanism may become blocked.

Also try to slow down the printer and observe if there has been any improvement.

I also made sure that no wheels are loose or binding, and checked that the beam is level with the rest of the frame using a digital level. I also replaced the stepper screw couplers because they were off-center, causing a wobble.
Should I try for an even higher VREF value for Z than 1.15? perhaps check the Power supply voltage?
Any suggestions would be helpful.

Hi


I quietly hope that our content of this topic.
Turning up current - A4988.

Personally, I am not in favour of setting a high current. But it may be worth checking for a moment for a test.
First of all, find out what is the nominal current of your electric drives. Next, you can consciously adjust the current.

Be cautious during experiments.

I think I'll decide to prepare a solid guide on the problems associated with the movement of the Z axis drive.
This topic is quite broad and, as you can see, it creates problems not only for users of DIY models.

As an experiment, try loosening the screws that hold the anti-backlash nut (which the z-axis lead screw runs through). If the z axis now moves easier and smoother up and down it's full travel, and you get zero skipping, then you have one of two issues. The fist likely cause is that the z-axis plate is not properly bent. I've seen many of these where that plate is not bent at a perfect 90 degree angle which causes binding of the axis. You may have to remove the plate and try to gently bend it to 90* with a hammer.
The second possible cause is that the lead screws are either bent, or have thread damage. If that is the case, you will need to replace the lead screws.

The printer shipped with all of the lead screw hub to bracket screws loose. I mistakenly tightened them. Apparently the brackets are not completely straight. I loosened the screws again and the binding issue is gone.