[Solved] Z-level calibration varies with temperature  

RE: Z-level calibration varies with temperature

Posted by: @bobstro

Posted by: @marklgoldberg

Does anyone know what Prusa's current position on this issue is? We can speculate in the forum what Prusa will and won't do all day. Has someone contacted support recently on this issue?

The "official" (public official in any case) response is on the GitHub issue page. I believe #636 is the most active. #561, #367 and and #309 seem to be duplicates.

Edit: Worth noting that some users assuming this is a MINDA issue have actually found other issues.

Reading them, #309 seems to be this issue and included the custom gcode. The others discuss issues such as failure to level and incorrect leveling over the area of the print bed, so they may be combining more than one issue. I don't see any of them with anyone assigned, but one is marked as a feature request and others as bugs. #309 is not marked as either, which is unfortunate, as it is the one most directly matching this issue without others to add confusion. Hopefully, someone at Prusa might give another look at #309.

Regards,

Mark

RE: Z-level calibration varies with temperature

Posted by: @marklgoldberg

[...] I don't see any of them with anyone assigned, but one is marked as a feature request and others as bugs. #309 is not marked as either, which is unfortunate, as it is the one most directly matching this issue without others to add confusion. Hopefully, someone at Prusa might give another look at #309.

I believe johnnydeer is a Prusa developer. He's in Prague at least!

If more people would contribute complete diagnostic, testing and result details (without getting heated) in the github discussion threads, as well as be willing to try some of the work-arounds, that is probably the best way to escalate the issue with Prusa directly. Documenting specifics including environmental issues is immensely helpful as there's no way they can recreate every user's environment. Although gcode may be distasteful to some, trying a few things out may help identify underlying issues or solutions.

RE: Z-level calibration varies with temperature

@marklgoldberg @bobstro

Here's my understanding and experience with the Github issues:

1. #636 "My mesh bed leveling failed and is printing unevenly" - has been linked to faulty M.I.N.D.A. probes / connection / wires, faulty assembly (anything loose), and incorrect M.I.N.D.A height, from what I've seen.

2. #561 - Likely a firmware problem, I haven't experienced or read up on this.

3. #367 - P.I.N.D.A. Feature request, no outlined issue discussion

4. #309 - "Z offset varies by 0.250 mm" - this is the very issue discussed in this thread, this can be caused by a multitude of things (I've experienced some of them), including: heat break slipping / heat brake screws not tightened properly, M.I.N.D.A. mounted too low or too high, faulty M.I.N.D.A., Temperature offset of M.I.N.D.A. probe, printer assembled poorly (loose screws / parts), and oddly enough a firmware bug.

Personally I've experienced: Firmware bugs, heat break slipping, M.I.N.D.A. mounted too low, and the Temperature offset of the M.I.N.D.A. probe.

Thanks!

RE: Z-level calibration varies with temperature

so... seriously, why didn't Prusa at least give us the option to purchase and use a PINDA instead of the MINDA? the buddy board supports it, the firmware can support it, etc... this whole business is ridiculous. 

I can get REFLECTIVE prints with my mini in PLA, it's GREAT when it's dialed in. but having to readjust the z between prints is infuriating.

RE: Z-level calibration varies with temperature

@arklan-uthoslin

That's the question we're all still asking. They have the tables for the P.I.N.D.A. v2 probe for the Mk3s printer, all it takes is pushing it to the mini and adding a way to reference it. It'll take a small amount of work since it's working with an ARM-style MCU, but it's really not that difficult. 

If I didn't care about the warranty and had a week to waste I'd do it myself. And I know almost nothing about coding...but I sure as heck can fumble my way through making custom Raspberry PI servers given enough time.

RE: Z-level calibration varies with temperature

Posted by: @drkmstr

@arklan-uthoslin

That's the question we're all still asking. They have the tables for the P.I.N.D.A. v2 probe for the Mk3s printer, all it takes is pushing it to the mini and adding a way to reference it. It'll take a small amount of work since it's working with an ARM-style MCU, but it's really not that difficult. 

If I didn't care about the warranty and had a week to waste I'd do it myself. And I know almost nothing about coding...but I sure as heck can fumble my way through making custom Raspberry PI servers given enough time.

yea, and knowing someones done it... argh. like, I'll pay for the part, just lemme have it!

RE: Z-level calibration varies with temperature

This is still a thing!

Didn't take long for me to notice this on my brand new Mini.  I didn't even know about this issue until I visited this forum.  

If I run a 1st layer calibration after a cold start or a long cool down, the layer barely sticks to the bed.

Run it a second time without changing any offset, the layer is textbook perfect.

Come on Prusa, you can do better than this.

RE: Z-level calibration varies with temperature

Im having same issue with my new mini I have to lower z after every print.  Support sent me a new minda but it did not change anything.  Hope it gets fixed or ill be forced to get a second mk3 I need another workhorse and thought mini was a decent solution.

RE: Z-level calibration varies with temperature

Another person with the same issue, I think. My printer came a few weeks ago after first layer calibration perfect. Go to print the head is to low, haven't hit the build plate yet but been close. Is this the same as others are experiencing? I didn't realise it might be due to a change in temperature.

What is the Solution here? (Without breaking my warranty) Just wait for Prusa to update Firmware?

RE: Z-level calibration varies with temperature

While I'm waiting for new firmware or a panda probe upgrade I put a marker clip on the upright extrusion.  It's about 60mm up from the bed.   Before I start each print I raise the z to that position.   Seems to help so far.   

RE: Z-level calibration varies with temperature

turns out for me i had a faulty MINDA probe. used to have to recalibrate multiple times between prints and such, regardless of temperature and preheating. once i spokewith prusa supprt and got the replacement (under warranty) installed i haven't had to adjust it once.

RE: Z-level calibration varies with temperature

Same faulty MINDA, got it replaced and is now working fine. Must be some production issues with the MINDAs.

RE: Z-level calibration varies with temperature

@withey89

I did contact them they told me the dev's were working on it and to raise nozzle up at leaast 50 mm after print.  I found the pre-heat fix here on the forum.  I am sending my x-y axis back under warranty for another issue so hoping I get "new" MINDA that works when it comes back.