Analysed problems with MINDA probe
Hello Community,
I would like to share my results of an analysis of my Prusa Mini.
Problem description
The bed leveling was fine and I startet a print (PLA 215/60°), which was sucessfull. Then I started a second print, and the first layer was more than 1mm too high. Fixed that with live adjustment. So far so good.
One day later I changed to ASA (260/100°) and the nozzle scratched my steel sheet and destroyed it.
That was driving me crazy and I made so many first level calibrations to fix it, bot nothing helps. For me the probe seems to be fine checked with this manual:
https://help.prusa3d.com/de/article/minda-testing_134024 --> All fine!
Then I went to a friend with a working Prusa Mini to do some tests... Our test setup was an RPI with octoprint and bed level plugin.
Results
First run with my Mini (cold state)
Recv: Bilinear Leveling Grid:
Recv: 0 1 2 3
Recv: 0 +0.093 +0.179 +0.075 -0.075
Recv: 1 +0.041 +0.186 +0.114 +0.028
Recv: 2 -0.062 +0.078 +0.127 +0.118
Recv: 3 -0.104 +0.059 +0.132 +0.108
Second run with my Mini (preheated from first run)
Recv: Bilinear Leveling Grid:
Recv: 0 1 2 3
Recv: 0 +0.141 +0.187 +0.077 -0.059
Recv: 1 +0.059 +0.197 +0.141 +0.090
Recv: 2 +0.057 +0.193 +0.210 +0.203
Recv: 3 +0.040 +0.179 +0.252 +0.267
Third run with bed temp 100°
Recv: Bilinear Leveling Grid:
Recv: 0 1 2 3
Recv: 0 +0.102 +0.190 +0.085 -0.072
Recv: 1 +0.076 +0.259 +0.212 +0.151
Recv: 2 +0.108 +0.283 +0.307 +0.273
Recv: 3 +0.076 +0.243 +0.315 +0.323
First run with another Mini (cold state)
Recv: Bilinear Leveling Grid:
Recv: 0 1 2 3
Recv: 0 +0.725 +0.488 +0.221 -0.032
Recv: 1 +0.811 +0.613 +0.366 +0.058
Recv: 2 +0.813 +0.582 +0.373 +0.112
Recv: 3 +0.799 +0.544 +0.375 +0.107
Second run with the other Mini (preheated from first run)
Recv: Bilinear Leveling Grid:
Recv: 0 1 2 3
Recv: 0 +0.746 +0.467 +0.201 -0.015
Recv: 1 +0.776 +0.554 +0.305 +0.031
Recv: 2 +0.781 +0.524 +0.319 +0.093
Recv: 3 +0.803 +0.531 +0.352 +0.126
Third run with bed temp 100°
Recv: Bilinear Leveling Grid:
Recv: 0 1 2 3
Recv: 0 +0.679 +0.454 +0.208 -0.042
Recv: 1 +0.790 +0.598 +0.368 +0.066
Recv: 2 +0.781 +0.564 +0.368 +0.116
Recv: 3 +0.761 +0.518 +0.351 +0.101
Reason and solution
As you can see, my MINDA probe seems to be more and more confused, then warmer it gets. So it is faulty. My replacement is one it's way for free by Prusa.
This seems to be a problem in general with this sensor and it is definitly not a work around to heat it up before as recommended by many in here.
It's just damaged and needs to be changed by Prusa ...
RE: Analysed problems with MINDA probe
Status update: New MINDA arrived, problems gone!
RE: Analysed problems with MINDA probe
Great, thanks for reporting back!
I’m waiting for replacement MINDA now as well. Hoping new one will be working correctly.
RE: Analysed problems with MINDA probe
Paper against heat - or magnetic interference?
may i give it a try...hmmm
RE: Analysed problems with MINDA probe
@toz
Well, after 2 months printing almost everyday.... it works. Z offset set to -0.905 since tests started
RE: Analysed problems with MINDA probe
[...] Well, after 2 months printing almost everyday.... it works. Z offset set to -0.905 since tests started
I don't have a Mini to test with, but I love the simplicity of your approach. If heat is the problem, insulate against the heat. It seems SuperPINDA is Prusa's long-term fix, but you've got a possible answer for those who can't or won't upgrade. Now I'm wondering if a reverse approach would have worked for PINDAv1 (which I do have). Build up a little heat mini enclosure around the PINDA to contain the heat.
This feels a bit like finally finding an elegant solution to problems I had on my Apple II computer. Late, but still good to know about.
and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan