Welcome to the SeeMeCNC Community

Hello,

So I finally got the Max working again, but am running into some...oddities.

To sum the prior:

* Updated carriages to the new version
* Tricklaser CF arms
* Added astrodyn dampers
* More disassembly-reassembly then I care to admit

The issue I'm having is with fluctuations in Z0. For some reason, when I use the rostock to zero, its fine and I get the paper-test working. When I try to do Z0 again, it can be off by +/- 5-15mm. There doesn't seem to be a pattern for where it goes wrong.

I'm not really sure how to figure this out. Mechanically I've tried tightening and checking things are square and such. Part of me is very uncertain about the new carriages, as I had a lot of issues getting them to ride the rails evenly across all three. Using the new script, I noticed that rather than the nozzles going up or down at the towers, it seems like they rise in travel between the towers and center.

I was able to get a few cubes printed, and they looked OK, though one wall was kind of bowed out - that is likely do to a lack of calibrations.

My last pass-through has the three towers at the right heights, but getting Z0 to stick has been...difficult.

Ideas?

What else might I be missing here? Going to try flashing EEPROM just in case: HR is 140, steps per mm is 80

A round number for H-radius is a pretty odd thing. Have you tried adjusting it to get them all at the same height? I had similar problems where I would set the Z0 for the middle, and the edges would be way off. Also, check that your endstops are fairly tightly mounted. they are small enough I've overlooked them often, and random fluctuations sounds like a mechanical, rather than a calibration issue. If you can get the same offset repeatedly with the same calibration, then it's a software/calibration issue. Also, belt tension is a possible issue. I'd double check it.

I'm fairly certain that from the described symptoms, it's a horizontal radius problem. Mine is using the seemeCNC ball arms rather than trick laser, and is ~143.27. You'll have to play with it to try and make corrections, or find the calibration spreadsheet Artxeeg (I think), posted here.

If it's off by 5+ mm it can only really be one of two things, either the endstops are moving, or your losing steps during the move home and back to the plate.
If it's the latter it's most likely mechanical, I'd check the inside of the belts for abnormal wear, then with the steppers disengaged run the carriages up and down by hand slowly feeling for sticky spots, and comparing the motion between the towers.
The former would be obvious if you wiggle the end stop switches, they shouldn't move.
It's also possible that the drivers have insufficient or too much current which can also result in lost steps, but with the digipots on the Rambo it's not usually the issue.

Xenocrates wrote:A round number for H-radius is a pretty odd thing. Have you tried adjusting it to get them all at the same height? I had similar problems where I would set the Z0 for the middle, and the edges would be way off. Also, check that your endstops are fairly tightly mounted. they are small enough I've overlooked them often, and random fluctuations sounds like a mechanical, rather than a calibration issue. If you can get the same offset repeatedly with the same calibration, then it's a software/calibration issue. Also, belt tension is a possible issue. I'd double check it.

I'm fairly certain that from the described symptoms, it's a horizontal radius problem. Mine is using the seemeCNC ball arms rather than trick laser, and is ~143.27. You'll have to play with it to try and make corrections, or find the calibration spreadsheet Artxeeg (I think), posted here.

I haven't done all the HR changes yet - mostly because I can't get the Z0 to stick. It's hard to properly diagnose whether I'm too high/low on any given area when it keeps fluctuating.

I went through my belts one more time, they should be solid. Endstops also feel solid. It's not quite the same offset - its +/- 5-15 depending. It's hard to say.

Polygonhell wrote:If it's off by 5+ mm it can only really be one of two things, either the endstops are moving, or your losing steps during the move home and back to the plate.
If it's the latter it's most likely mechanical, I'd check the inside of the belts for abnormal wear, then with the steppers disengaged run the carriages up and down by hand slowly feeling for sticky spots, and comparing the motion between the towers.
The former would be obvious if you wiggle the end stop switches, they shouldn't move.
It's also possible that the drivers have insufficient or too much current which can also result in lost steps, but with the digipots on the Rambo it's not usually the issue.

The belts seem to run OK - I don't feel any sticky or sliding spots. That said, I had some issues getting the new carriages to work properly. I haven't discounted something being wrong on that end. I might have to disengage the belts and do the fall-test again to see if one or more of the carriages are not falling uniformly.