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BoxJockey
(@boxjockey)
Active Member
Bed Adhesion Issues

I have been using my printer for almost six months with nothing but success. I honestly have not had to trouble shoot anything up until this point. However recently I have been having issues with corners lifting off the bed.

I went through an entire spool of this filament with no problems, so I ordered another.
https://www.amazon.com/gp/product/B016EH6VF0/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1

Currently sitting at 215 on the hot end and 55 on the bed which has worked on everything up until this point. I have not altered any slicer settings. I wipe down the entire bed with 93% Isopropyl alcohol before every print. As an example the Prusa logo test print has printed fine in the past but now the corners lift.

Since the problems began I have tried both increasing and decreasing hot end temp. Both increasing and decreasing bed temp. I have tried printing on different areas of the bed, and different Z rotations all with the same result. Last night I did a full re-calibration but still no luck. I have also tried another brand of PLA that came fresh out of a sealed bag and while it was slightly better, the corners still lifted. I had seen some posts suggesting a light sanding of the PEI coating but that seemed a little scary as I have done everything in my power not to damage it thus far. I am all ears for any suggestions!!

Posted : 22/08/2017 12:06 am
benjamin.s9
(@benjamin-s9)
Active Member
Re: Bed Adhesion Issues

Have you tried printing on different sections of the heat bed? Maybe the entire heat bed is not heating correctly.

Posted : 22/08/2017 1:33 am
BoxJockey
(@boxjockey)
Active Member
Topic starter answered:
Re: Bed Adhesion Issues

Yeah, I tried sort of north south east west around the center and then out towards the extremes of the build plate but no dice. Is there any chance PEI weakens over time?

Posted : 22/08/2017 1:36 am
aaron.s5
(@aaron-s5)
Noble Member
Re: Bed Adhesion Issues

Something to try. My experience is that IPA is great at removing some contaminates, but not all. I use IPA between prints, but every once in a while I do a more thorough cleaning doing three steps.

1) Windex. Seems to remove oils, but does leave a residue.
2) Acetone. Seems to remove plastics and dust.
3) IPA. Seems to remove other things.

This thee step combo usually gets my bed back in a nearly new place.

Also, I presume you have not had a Live Z Adjust change that is masquerading as Bed Adhesion Issue?

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Posted : 22/08/2017 1:55 am
Rob Nance
(@rob-nance)
Eminent Member
Re: Bed Adhesion Issues

I find on large flat prints a bed temp of 62 with PLA makes everything happy, stops any warping. Also, it might just be the filament, or the time of year, the print/s, so don't let the fact that it's worked fine until this point make you think there isn't room to improve/alter based on the slice.

Posted : 22/08/2017 5:52 am
mavu
 mavu
(@mavu)
Estimable Member
Re: Bed Adhesion Issues


Something to try. My experience is that IPA is great at removing some contaminates, but not all. I use IPA between prints, but every once in a while I do a more thorough cleaning doing three steps.

1) Windex. Seems to remove oils, but does leave a residue.
2) Acetone. Seems to remove plastics and dust.
3) IPA. Seems to remove other things.

This thee step combo usually gets my bed back in a nearly new place.

Also, I presume you have not had a Live Z Adjust change that is masquerading as Bed Adhesion Issue?

I second this, but only the second step.

I use acetone exclusively, and it restores the stickiness wonderfully.
Acetone removes fats and oils much more thoroughly than ipa ever could.

Posted : 22/08/2017 12:14 pm
bob.b2
(@bob-b2)
Trusted Member
Re: Bed Adhesion Issues


I had seen some posts suggesting a light sanding of the PEI coating but that seemed a little scary as I have done everything in my power not to damage it thus far. I am all ears for any suggestions!!

Dont be scared, just do it. But use a fine grit paper, 1000 or more.. I use 3000 grit wet sanding "sponge". Just a few strokes is enough, you will see the color change and your PEI will work like new again. And considering the thickness of the sheet, and how little a 1000+ grit paper removes with a few strokes, you can almost certainly do this until your printer falls apart.

Posted : 22/08/2017 1:09 pm
JeffJordan
(@jeffjordan)
Moderator
Re: Bed Adhesion Issues

it might well be that your pinda has hit something during a (failed ?) print and dislocatet itself a little bit, especially when you are using the mk2s design. or that the +5V Vcc voltage changed a little bit (due to a degrading capacitor), which affects the pinda sensitivity.

so I would check the first layer setup again.

dem inscheniör is' nix zu schwör...

Posted : 22/08/2017 5:47 pm
BoxJockey
(@boxjockey)
Active Member
Topic starter answered:
Re: Bed Adhesion Issues

First off, thank you all for the rapid responses! This has been a huge help!!

So I scooped up some acetone to give the bed a good cleaning. Then I followed that first layer setup post which definitely identified some setup issues on my end. After all that the Prusa logo printed just fine, however I am still hitting a snag on the print that started all this, but I have a feeling it is more a lack of understanding on my part than anything else. But before I get to that I wanted run this by you all. Below is the final first layer test print (the single layer 75mm by 75mm square), the one I ended up calling a success. Apologies for not being the best of pictures:

This took place after a full XYZ re-calibration and I have not moved the printer or anything like that. It might be hard to see in the pic, but in the bottom right corner (which is the side towards the LCD) there are little gaps where the diagonal lines meet the perimeter. These are absent at the top right. In fact the lines themselves at the bottom right are visibly less flattened that the top left. Like the entire bed is angled up from the bottom right to the top left. Is that something that should go away with re-calibrations?

Back to the issues with the original print. From some reading I have done it seems like it might be related to corners, but here is my question. So the Prusa logo prints fine and it has 90 degree corners. If I were to make that first layer test a cube (so 75x75x75) should I realistically be able to print that without a brim and not have the corners lift? Perhaps asked another way, does the prusa logo work only because it is relatively small? Again, thank you so much for all the help on this!!!

Posted : 24/08/2017 3:24 am
JeffJordan
(@jeffjordan)
Moderator
Re: Bed Adhesion Issues


....
If I were to make that first layer test a cube (so 75x75x75) should I realistically be able to print that without a brim and not have the corners lift? Perhaps asked another way, does the prusa logo work only because it is relatively small? Again, thank you so much for all the help on this!!!

it should be no problem to print such a cube without any brim, in fact it should be the default procedure !
the larger the surface between pei-sheet and object, the better the adhesion.

so you only need a brim if you've got tiny objects with a small base... or if they are relatively tall... or if your first layer setup is poor!

but don't try to print a "solid" block (infill=100%), use an infill of about 25% or 33%.

if you dialed in your z-live adjustment properly and got your pei-sheet cleaned up tidy, you may even run into issues getting the cube loose from the heatbed. so it might be a good idea to add a mouse-ear at a corner, which you can use to loosen the part (getting your spatula under it).

dem inscheniör is' nix zu schwör...

Posted : 24/08/2017 1:30 pm
BoxJockey
(@boxjockey)
Active Member
Topic starter answered:
Re: Bed Adhesion Issues

Hmmm, I will try cleaning again. What I am trying to print is a rectangle with the shortest side being roughly twice the length of the shortest side of the Prusa logo. Logo works great but the front two corners on the larger rectangle always pull off the bed mid print.

Should I be concerned at all with that variance in the single layer test or is that pretty standard?

Posted : 24/08/2017 8:53 pm
aaron.s5
(@aaron-s5)
Noble Member
Re: Bed Adhesion Issues

There should be little variance to the Live Z level. People have identified two issues that lead to variances.

1) When you start the print (starts with pre-heat then Cal test, then starts to print) if you start with the print head low to the heated surface, it seems to affect the PINDA sensor. If you start each print with Z at ~100mm or so, this seems to mitigate it. People have modified the start up .gcode to also address this, search the forum. I have found very little variance when I start the print with the extruder up.

2) The center two screws that hold down the bed can come loose with all the motion and vibration. If they are loose, the bed actually moves and this results in what appears to be variability in the Live Z setting when it is really a variability is Z.

Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss. If you solve your problem, please post the solution…

Posted : 25/08/2017 2:28 am
BoxJockey
(@boxjockey)
Active Member
Topic starter answered:
Re: Bed Adhesion Issues

Double checked the screws and all was snug. I typically start a ways above the bed (maybe 60-70mm) just because it is easier to grab any stray filament, but I will give it a go at 100!

After reading through Jeff's first layer post I have another question though. I noticed several people mention, Jeff included I believe, that once the single layer test print is completed it can be very hard to remove from the bed. In my case, I lay a razor blade flat on the bed and then angle it up just enough to get under a corner. With one corner loose it pulls off really easy. Should it not be that easy? If so, would that suggest there is still a cleanliness issue with the bed?

Posted : 28/08/2017 5:42 pm
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