MESH leveling not working properly? 1st layer height issues.
 
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Rat_Patrol
(@rat_patrol)
Trusted Member
MESH leveling not working properly? 1st layer height issues.

Yup, another one of these. 

Video of what its doing:

https://photos.app.goo.gl/2UAmUAEzMryZL2hr6

I have been printing for about 4 years now, having completely rebuilt a couple printers, so I'm not a novice.

So far I have done with no change:

  • Installed 4.0.1 fw. Then backed up to 4.0.0. A couple factory resets.
  • Loosened and then re-tightened the 3 screws holding the X-Z assembly onto the Y assembly
  • Loosened and then re-torqued the bed screws. Torque specs on all assembly screws from Prusa would be nice...
  • Received/installed a new MINDA probe (after it failed to home at all after a couple days of printing)

Been back and fourth with Prusa CS via email and chat, nobody knows what to do.

Its kind of hard to use this machine with the first layer being completely all over the map. Fat chance of even attempting the textured sheet, which sits in the corner until this is resolved.

Thoughts?

Posted : 08/01/2020 4:58 pm
MrTeliP liked
Alpengeist
(@alpengeist)
Eminent Member
RE: MESH leveling not working properly? 1st layer height issues.

have you already solved the problem?

Posted : 17/01/2020 10:26 am
Rat_Patrol
(@rat_patrol)
Trusted Member
Topic starter answered:
RE: MESH leveling not working properly? 1st layer height issues.

Not really. Loosening the XZ assembly to Y assembly screws to get better manual alignment has made the problem manageable, and I can continue printing smaller parts in the middle of the bed. Currently, the back-left of the bed seems to be high, and the first layer is squished to near contact with the nozzle there.

 

According to the Prusa tech I had on chat last, the ABL doesn't really work yet. I guess there is some MESH capability, but the bed needs to be level for it to work. I was assured they are working on it and to keep checking for a new FW release.

Posted : 17/01/2020 4:23 pm
Alpengeist
(@alpengeist)
Eminent Member
RE: MESH leveling not working properly? 1st layer height issues.

I watched your video ... I had exactly the same thing on a MINI ... the second one runs great ...

try to loosen the heating bed completely ... so remove all nine screws ... carefully pull the heating bed out towards the back ...

you now see the hexagon bolts on the table ... turn them all loosely ...

Now turn it with your tool until you feel a slight resistance ... then turn it about 1mm further ...

you do this with all bolts ...

when you have done that, slide the heating bed back into position and screw everything just as tight as with the bolts ...

do you know the crosswise screwing of a surface?

 

it worked for me ... even the first time ... Z leveling works ...
and the first layer of a printed part also looks flawless ...

my reasoning was:

when a part is heated ... it expands ...
but if a part is screwed tight and heated ... then it cannot expand homogeneously and begins to bend ...

Our heating bed is screwed down nine times ... this results in four caged areas that expand differently when exposed to heat

by screwing the heating bed on more easily, it can expand better ...

Then there are the hole tolerances of the bolted bolts ...
this is where our plate comes in and is forced into a position with countersunk screws ...
the heating plate is nothing more than a circuit board made of FR4 material ... and has this material
through their production a certain direction of expansion ...

hope you have success with it ... I'm definitely glad that it works for me again

Posted : 17/01/2020 5:22 pm
Rat_Patrol
(@rat_patrol)
Trusted Member
Topic starter answered:
RE: MESH leveling not working properly? 1st layer height issues.

I have actually replaced the Y carriage (original had a slight warp, Prusa send a new one), so I have been through those bolts. I'll back them off though, make them just snug enough to not loosen up on their own. Hopefully it works!

I also just completed the heat break fix, so far extrusions are looking much better.

Posted : 17/01/2020 5:27 pm
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