Y tower shift

[CatDog]

All right, I need help. When I get the bed level I've had to add long set screws in order to do so. Then when printing the layers are all level but as it print they shift away from the Y tower. I've checked the skates, belt tension and the stepper mount screws also checked the wiring for any cross interference. When the set screws are all about even when I lower the head it swings away almost an inch from center. Nothing has fixed it. What else can be done or looked at to fix this?

[Boundless]

Hi,

I am a little confused as to your leveling of the bed. Where did you put long set screws? Are you referring to the end-stop screws at the top? Do you have an example print you could show us?

If there is no play / wobble in your skates and they glide fine on the track, and your belt tension is not too tight or loose, then check every u-joint. Make sure they move freely. I would disconnect the effector platform 2 arms at a time and lift the arms and see if they move freely. Also, spin the u-joints by hand to make sure they are moving freely.

Check all 12 joint connections...think smooth thoughts....

Recalibrate your z height at temp and run through your Scripts in Repetier for bed leveling the X,Y,Z and make sure there are no typos in there.

I hope this will help somewhat diagnose whats going on.

[CatDog]

All of the mechanics look good, the screws were added to the end stops. I've leveled @temp as per instructions and the scripts are all correct. I added the longer set screws because the Y tower calibration was going into the bed and I had to raise it. Y tower end stop is about 1/2 inch different from the X and Z for me to get level with the bed. When printed the Z axis layers are all even, X and Y axis are off.

[dtgriscom]

All of the mechanics look good, the screws were added to the end stops. I've leveled @temp as per instructions and the scripts are all correct. I added the longer set screws because the Y tower calibration was going into the bed and I had to raise it. Y tower end stop is about 1/2 inch different from the X and Z for me to get level with the bed. When printed the Z axis layers are all even, X and Y axis are off.

This is really weird. The fact that your printed part is parallelogrammed means that when the printer tries to move vertically it actually is moving at an angle. But, for the nozzle to move vertically, the end stops don't have to be correctly adjusted, and you don't even have to have the same length delta arms; the Cheapskates just have to all move the same distance up and bingo! vertical. So, if things slant away from the Y tower as the print progresses, then the Y Cheapskate must be moving less than the X and Z Cheapskates. If I'm right, then you had to lengthen the Y tower end stop screw a whole lot more than the X and Z end stop screws. (You weren't clear; is that the case?)

Some things to check:

- Use Repetier-Host to move the effector platform a fixed distance vertically, and measure the motion of the three Cheapskates. They should all move the same distance: do they?

- Is the Y belt seated fully into the Y drive gear? How about the X and Z belts?

- Might you have a different number of steps-per-mm for the Y tower than for the X and Z? Use Repetier-Host to view the printer's EEPROM to see. (I'm sure this could cause what you're seeing, although I'm not sure how it might have happened.)


Let us know,
Dan

[Boundless]

This is strange,

I agree with Dan. It sounds like your Y is not moving enough. Perhaps moving less steps.

And you said the belt appears in good condition? I would think this would happen if the belt was slipping off the stepper gear or it's jumping over teeth on the belt.

Could the gear on the stepper itself be slipping on the stepper shaft? Remember those tiny screws you had to tighten with lok-tite? I wonder if that's it.

Just a theory on my limited experience. I'm new here.

[Tinyhead]

The fact the layers are all still lining up properly suggests to me that it's not a belt or slipping issue.

CatDog, as you mentioned yourself, the Y cheapskate was driving into the bed... you need to complete the bed levelling calibration. You shouldn't have to add longer screws. If one of them is 1/2" difference, it's going to make nothing but problems. It would also explain why the effector sits about an inch off of centre when it's lowered.

[geneb]

I'd check to make sure that the height stop screws are resting against each tower. That's the only thing I know of that would explain having one screw so wildly out of line with the others.

g.