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Uneven First Layer (how accurate is the SuperPINDA?)  

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uHu
 uHu
(@uhu)
Active Member
Uneven First Layer (how accurate is the SuperPINDA?)

Hi

Already using the MK3S+ for some time and never had 1st layer issues (or I didn't notice).
Now with TPU I got some waves on the 1st layer from being too close. So I readjusted the Z-Calibration.

Going back to PLA, I noticed this:

I redid the XYZ Calibration on the Printer, but nothing changed.
I also turned around the powder coated bed (so front is on the back), and it changed almost nothing.
So it seems, that the heatbed is slightly higher at the front.

Now, I am a bit confused.
I thought the PINDA probe would measure those differences and the printer would automatically compensate for it.
(I use the standard setting with the 9 points, which are probed before the print.)

 

When I set -30 for the rear in the Bed Level Correction, I get this:

So the difference seems to be slightly bigger than 30µm.
Also there seems to be a further valley in the middle.

This seems to be like a lot to me.
I am not sure, if the mesh of the probe is actually used.
When I watched the Z-axis motors closely, they also did not turn at all, when the printhead was moving over the bed printing the Perimeters (suggesting a perfectly flat surface).

Just some days before I could see them rotating, when moving from left to right on the X-Axis ... but that was before I redid the XYZ-Calibration.
So it seems, that it's working.
I am just puzzled, why it's not doing anything now to compensate for the >30µm differences. Is this just below the accuracy of that probe?

Posted : 08/11/2022 10:33 am
uHu
 uHu
(@uhu)
Active Member
Topic starter answered:
RE:

I did a proper 1st-Layer-Test now.
The following image was made with the Bed Level Correction reset to zero.

Especially strange is the field marked with "L", which seems to be too far away from the nozzle, while the fields left and right beneath it seem closer.
With the 9-point probing, this spot is not measured. But comparing the top middle field to the bottom middle field, there's still a difference at 2 measured spots.
Still not sure, if this kind of deviation is normal for the SuperPINDA probe.

It might be worth mentioning, that it's pretty cold in the printing room right now (open window).
So this might have an influence (by warping the bed more when heating .. or influencing the temperature-compensation of the probe).

This post was modified 1 year ago 3 times by uHu
Posted : 08/11/2022 1:00 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Uneven First Layer (how accurate is the SuperPINDA?)

Super pinda is not temperature compensated. It may be hanging as it warms up during the probing .

Try auto homing your extruder before starting the next print 

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

Posted : 08/11/2022 2:28 pm
Neophyl
(@neophyl)
Illustrious Member
RE: Uneven First Layer (how accurate is the SuperPINDA?)

Also you might want to turn on 7x7 probing from the lcd menu for better coverage.

I always preheat for 5-10 minutes first to give the bed time to equalise and with the old non super pinda that has a thermistor inside I get that to a set working temp using the bed preheat before probing and with that set up its is very consistent.

Posted : 08/11/2022 2:35 pm
uHu
 uHu
(@uhu)
Active Member
Topic starter answered:
RE: Uneven First Layer (how accurate is the SuperPINDA?)

Thx for the tips!
Will try them out later. Have a print running right now.

Posted : 08/11/2022 2:52 pm
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