Z-level calibration varies with temperature
Hi,
I'm having issues with first layer calibration on my MINI. The difference between cold printer z-level value and after finished print is about 500, so I need watch and adjust first layer with every single print.
Is anyone having similar issue?
Support confirmed that M.I.N.D.A. doesn't have a thermistor unlike P.I.N.D.A. on Mk2.5 or Mk3 due to MINI being a low cost printer. That explains why I've never run into this with my old Mk2.5.
I was checking the buddy board schematics and firmware a bit and there is one pin on the probe connector that is for thermistor and currently it's not connected, but I've haven't been able to identify if it's actually used in the firmware.
Since PINDA is only 90Kc ($3.50) more expensive than MINDA I don't really understand why it was decided to save MINI cost here.
Has anyone thought or tried to use PINDA in MINI? If it works, I'd go for it and buy it from Mk3 spare parts, but I thought I'd rather ask here before I dismount it from my Mk2.5 just to try.
Thanks,
Honza
Best Answer by Honza:
I've ordered SuperPINDA on Black Friday and upgraded yesterday. https://shop.prusa3d.com/en/spare-parts/1396-superpinda.html
Calibration is no longer messed up and holds at any temperature.
First print today started at 15C, second at 30C (enclosure temp after 2 hours of ABS printing), both kept the same z-level perfectly.
Prusa engineering did an awesome job in fixing this.
Thank you!
RE: Z-level calibration varies with temperature
I am experiencing the exact same issue. I made a quick spreadsheet with linked plots showing the differences.
https://docs.google.com/spreadsheets/d/1n3qKVI80dKMmc-eSm6O3HZD5gDbHZ-0_29ghAAEJTq8/edit?usp=sharing
Prusa Mini Silicone Bed Leveling Mod: https://bbbenji.github.io/PMSBLM/
RE: Z-level calibration varies with temperature
I've experienced the same thing. I just did several G29s and started off being off in the .2mm range and ended up almost 2mm out after 20 minutes of the bed and hotend heated to 170c and 50c. Seems like it could be problematic getting a consistent first layer.
RE: Z-level calibration varies with temperature
The Mk2, never had a thermistor on the Pinda, and it was a bit of a problem
so the "antidote" was to always start in the same way..
I start with the extruder at 60mm height, and to the left of the heatbed, heat the printer,
then do Live Z...
if it needs a second session, raise the extruder to 60mm and complete live Z again...
then when you start the next print, raise the extruder to 60mm again, and then heat the printer so that the the settings are as similar as possible for each event.
regards Joan
I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK
RE: Z-level calibration varies with temperature
I've experienced the same thing. I just did several G29s and started off being off in the .2mm range and ended up almost 2mm out after 20 minutes of the bed and hotend heated to 170c and 50c. Seems like it could be problematic getting a consistent first layer.
^ It is. I barely got my new printer printing.
I'll try writing some GCODE tonight to get the probe temperature stabilized based off of what I'm learning about the Mk2. oof. :I
RE: Z-level calibration varies with temperature
I'm experiencing the exact same issues as described here. It has been impossible to get a consistent z-offset value. It's too high, then too low, and it keeps going back and forth. Quite frustrating. I hope a fix is developed for this very soon, either via software or hardware.
RE: Z-level calibration varies with temperature
Unfortunately I have exactly the same problem: the z-level does not hold calbibration, it is pure chance if a print works. Live adjust is not a real option, as the start of the part is already ruined. When I restart the print, the z-level has already changed again and ruins the next attempt.
Unfortunately I have to put the MINI aside until a good solution is found 🙁
RE: Z-level calibration varies with temperature
My workaround has been to preheat my Mini for at least 5min before I begin printing from a cold start. This has eliminated the problem for me and can get clean reproducible prints every time.
Prusa Mini Silicone Bed Leveling Mod: https://bbbenji.github.io/PMSBLM/
RE: Z-level calibration varies with temperature
I will try that. Thank you for the hint.
RE: Z-level calibration varies with temperature
Are the MINDA and PINDA physically the same size, so are they interchangeable from a mechanical point of view?
Texy
RE: Z-level calibration varies with temperature
What I have read the PINDA has 1 wire more(4 wire), the MINDA(3 wire) and there is no pin to connect on the Buddyboard -- but correct me if i am wrong
Mini with FW:4.4.1 + SuperPINDA + Bondtech Heatbreak + PC4-M8 couplers + 1 piece boden
RE: Z-level calibration varies with temperature
@oxygen
It looks like the board has a 4-pin connector.
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Look at the top left connector, that is where the MINDA probe connects to.
Also if you look at the footage from ERRF 2019, they're using a PINDA on one of their minis.
RE: Z-level calibration varies with temperature
I have a feeling that the PINDA probe probably is compatible with the MINI, because if you look at the Buddy board schematics, you see this:
RE: Z-level calibration varies with temperature
Also, the back side of the Buddy board looks like this:
RE: Z-level calibration varies with temperature
OK, that is good news. do we know if the firmware is doing something with the value coming from the thermistor?
My best guestimate is that in the mk2 of the mini we are going to replace the MINDA with a PINDA
Mini with FW:4.4.1 + SuperPINDA + Bondtech Heatbreak + PC4-M8 couplers + 1 piece boden
RE: Z-level calibration varies with temperature
OK, that is good news. do we know if the firmware is doing something with the value coming from the thermistor?
Do you mean if a PINDA was fitted to a Mini? I''d be surprised if the firmware supports it (by default), but if earlier demo Mini's have it, as suggested by posts above, then it'd be a 'good thing'.
Texy
RE: Z-level calibration varies with temperature
It is good news that the Buddy board has the ability to host a Pinda (with 4th wire for a thermistor) Personally I feel a little bit of sadness why PR switched from a proven concept with temperature compensation to one without.
But then there is room for us to buy upgrade kits for our printer (good thing) I understand why a € 4.09 difference between a PINDA and a MINDA (on a total cost of 15.08 for a PINDA) is a big thing an PR wanted to address a bigger audience and had to lower the total cost.
I feel while rambling on that I am still torn, but trust the people at PR to address this.
Mini with FW:4.4.1 + SuperPINDA + Bondtech Heatbreak + PC4-M8 couplers + 1 piece boden
RE: Z-level calibration varies with temperature
I sure hope this gets addressed as well. Its a pain to have to raise the z axis every time. Makes me sad as I hoped the mini would have been as pain free and user friendly as the MK3. Prusa to the rescue PLEASE!!
RE: Z-level calibration varies with temperature
My workaround has been to preheat my Mini for at least 5min before I begin printing from a cold start. This has eliminated the problem for me and can get clean reproducible prints every time.
I tried that and it works reasonably well. I still hope there will be abetter solution. Thank you for your help.
RE: Z-level calibration varies with temperature
Same issue here. Every Mini will have this issue. Is there a way to automate the 5min preheat?