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LePaul

Lot's of trouble leveling bed since heated bed install

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Hi...so with my UMO, I am used to heating the print head to 180 and using a sheet of paper to level the bed.

Since the heated bed, its very problematic.

I heat the bed to 70C and the printhead to 180

I used a sheet of paper and use the 3 points, making sure the paper can pass through.

However I notice on the outer edges of the 3 points, say the center area (left of and right of), I have to adjust for those areas further.

About 50% of the time, once the print starts, somehow the alignment is off and now the bed is too close.

I've been using a business card (the one that came with the ColorFabb filament) hoping that a bit thicker paper might be the cure. Well, now I don't have that smooshed-down plastic we want for the first layer.

I don't see a way to calibrate through the Ulticontroller...so I've continued to experiment manually.

Help!

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Are you leveling with the nozzle on top of the 3 point screws? You shouldn't be leveling the back left and right or you'll go insane since you'll be leveling 4 points with 3 point leveling.

This is what I would do:

Level the Center back position first, with the nozzle directly over the screw. Tighten the screw until you feel a bit of the spring tension. You want this somewhere in the middle in terms of tension so you can loosen or tighten later.

Adjust your Z-end switch so that it approximately clicks at that position.

Now fine adjust the leveling screw in the center back so that the glass is paper length away.

Do the same for the front left and front right corners (again directly over the screw)

This should get you pretty level. Print this pattern and fine tune the screws until you get your nice smoosh, and proper sticking. (scale by 2x) https://www.youmagine.com/designs/bed-level-pattern

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As i see it the heat bed kit is the same as the one in the UM2?

If so when you adjust the rear point, you have it so it only just starts to bite the paper. so you can easily slide the paper in and out from under the nozzle but its touching.

as the front screws are all the way in the front of the glass, the glass can deflect. so if the rear screw is adjusted tight onto the paper then the front will deflect heaps before it gets to the same level of tightness.

Then you adjust the front so its the same as the back. You can slide the paper in and out from under the nozzle but it touches and the glass doesn't deflect downwards when you push the paper under.

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You are right. What I do it's to level on the three points, (bed deflects indeed). Then I move the head a bit inside (imagine a triangle and make it smaller) like 2-3 cm in each side of the triangle. Then readjust. That's why I use a gauge feller. To make a 0.08 pass without friction and a 0.10 that can't pass (and that you see that front sides deflects). Gauge fellers are like 2-4€.

Edited by Guest

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"I've been using a business card (the one that came with the ColorFabb filament) hoping that a bit thicker paper might be the cure. Well, now I don't have that smooshed-down plastic we want for the first layer."

Using a thicker card means your z-offset is larger so your bed is further away from the nozzle, giving your that result. Also bear in mind that sheets of A4 paper can have a different thickness depending on where you are or where they were manufactured. eg UK seems to be different to mainland Eu.

I use a thicker card for levelling but I change the z-offset in the gcode to adjust the nozzle to bed difference.

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Just to be sure, like yellowshark says...

Read this post

https://ultimaker.com/en/community/10335-glass-plate-not-flat#reply-91504

I had one bed of y umo+ with that and just had to drill a bit the screw holes so they didn't curve my glass.

Also I had other bed that was curved on the front center, but I fixed that by a bit of brute force (I still have a 0.05 gap on the front, but since the glass it's flat and it's so small gap, it doesn't affect the heat.

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Good day

I don't think the glass is warped and from what I recall of the assembly, the screws sank into the countersunk holes completely fine. But it is certainly worth checking the glass and re-examining those holes.

I was wondering how far those screws should be tightened on the bed. Ultimaker's document only said "Don't screw them in too tight". I think your suggestion about a measurement makes more sense (again, I wish they would review their documentation)

assembly.JPG.831f3d6870b398069260faf53889b5a3.JPG

The order of calibration you mention also makes good sense! I felt like I was going in circles with some test prints. I had the right gap height going on, start print and then it was suddenly too high and no plastic being extruded. While the print was still trying to run, I attempted to slide a piece of paper between the print head and bed...it wouldn't fit through.

I also have a minor problem with the z-cap rubbing on the back left of the machine.

Now the documentation on the bed leveling annoys me some...notice there is step 73, 75 and 76. Where is 74! As someone that does documentation in IT, stuff like that drives me crazy :O

5a3316cdd552a_bedlevel.thumb.JPG.bcf9e4e617b25cdc0bf6f4ccb76e834b.JPG

assembly.JPG.831f3d6870b398069260faf53889b5a3.JPG

5a3316cdd552a_bedlevel.thumb.JPG.bcf9e4e617b25cdc0bf6f4ccb76e834b.JPG

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When you look through the bed (aluminium and upper metal/glass) you will see the black connect (heat/pt100). You can screw as much as you want, but don't let the black connector touch the aluminium by 2mm or so.

 

Ok, so as far as the bed height/distance you are referring to....

I had a printed robot and tipped it sideways, sort of used that as a 'jig' so to be best guess, all three screws were in an equal distance

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YOU ARE ALL DOING IT WRONG!!! MY WAY IS BEST!!!:angry:

lol. Mostly just kidding.

Once you level with paper, never do it again. That gets you close. Then level by printing a skirt or brim or just printing your next part. As it does the brim turn all 3 screws THE SAME AMOUNT. It's a panicked feeling the first time trying to hurry up and adjust before the skirt is done. But you should adjust during the start of EVERY print as it's good practice. Even if you turn them all 1/4 turn and then turn them back. This way you know instinctively which way to rotate to squish more or to squish less. By the 10th time it will be a non-thinking action. you will just reach to a screw and turn it the right way to squish more (or less).

If you then find it's levelled perfection in one corner but not another then you can turn the screws different amounts. Advanced adjustment is that when a corner without a screw needs to go up you think of the whole glass as a see-saw. For example if you want to squish more in the back left corner you want bed to go up there so down in the front right corner. But to not mess up the previously perfect leveling on the front right you adjust the other 2 screws up to bring the front right back where it was.

It's rare that I have to do this extra step - really the "paper method" gets it level quite well and then the on-the-fly method gets it just right.

Also note that on the UM2 the printer sets the bed at ".8mm above 0" position also known as Z=0.8mm which is about right for a piece of paper.

But on the UMO you are leveling the Z=0mm position. So you want it tight on the paper. Or alternatively after leveling squish the bed up into the nozzle by about 0.5mm or 1 full turn (M3 screws are 0.5mm thread pitch so .5mm for each full rotation).

One more thing - usually if it's clearly not squishing enough I do a half turn at a time. If it's close but needs slight tweaking I do about a 1/4 turn at a time.

To get parts to stick to the glass (or tape) you need to level it a bit squished which is more squished than the normal technique gives you with a tiny elephant foot on the bottom layer only. For parts that don't need to stick but need to be more dimensionally accurate and where you don't want to cut/file off that elephants foot then you level it not-so-squished.

Edited by Guest

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For my prints I did that method, but I had different prints on repetition and I did a mix of your stuff.

I launch a print (almost always first layer at 0.3). Then I print a 50x50mm flat square and adjust the stuff manually after a calibration. Then when the lines are at the 'good spot', visually speaking, I stop the print, remove the printed layer (one layers peels off hot without any force) then I cold down the head (at 90 clean it to remove residue) then I do home and move the head to the area where it was printing a great first layer. For me that's 0.08 gauge (umo+) passing without almost any force (but vibrating with the head fan (I have one fan like um2 pointed to the ptfe&peek). 0.1 gauge passes hard.

This method allows you to repeat over and over the first layer as you see fit without manual adjustments.

Ofc you need a gauge feller to measure the distance.

Edited by Guest

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