My printings get all very skewed

#1

First of all Hi, to the Forum. OK. Now, I’m having a quite serious problem with the resulted prints which seem skewed to the Y-axis as I indicate to the attached pictures I’ve uploaded. I have noticed by having used different resins, that when I decrease the print speed on cura profile, the problem seems to get corrected although it takes too much time and playing with laser power too. I’m building with layer height of 0.050 mm and the recommended print speed of 130 and laser power of 58 doesn’t seem to help.

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#2

Not all resins are created equally - the settings for the 50um profile are based on you using the peopoly resin and not third party resins. What is the resin being used, is it listed in the suggested resin exposure settings spreadsheet, and are you using the recommended settings for it?

Also, are you using the latest moai cura version of 2.6.2 -14? Asking because that seems to be a continuous theme/problem lately of people not having installed the latest software and profiles.

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#3

what type of resin is that? can you also share system settings and your leveling numbers per the Leveling Wiki
http://wiki.peopoly.net/doku.php?id=moai:leveling

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#4

Hi! The resin I used is the Nextdent (Purple) which is listed as a brand in the suggested resin exposure settings spreadsheet, but because of its color I used values close to the Funtodo resin settings (pink). So I’ve built in 50um with various Print Speeds( 15,30= destroying the table in combination with low power such as 46,54)After having corrected “I suppose’’ the z-leveling by having screwed clockwise and opposite the 4 bolts , having done the hand corrected calibration by focusing the laser cross in the center printings still get skewed. Of course I have used the Peopoly’s Gray resin as well but with the same skewed results. To tell the truth this is happening occasionally which makes things even harder to get an assumption. For example if I try to print four objects the 2 may print well when the other 2 will fail. Currently I’m using the latest firmware for the Peopoly Moai printer and the 2.6.2 Cura version as I find that this combination works best and 2.6.2 environment is more suitable for me. My current printer and cura settings and the A,B,C & D cylinder heights for the z-leveling are as follows:
A=10.68 / B=10.70/ C=10.32/ D=10.67.
X Size= 896 , Y Size=911, X deviation=100, Y deviation=100, Smooth=50, Z moto speed=8, PM moto speed=30.
ADVANCED SETTINGS:
Laser Power=49(For the ring).For the 4 cylinders=58. XY Speed Set=4, Z Reset Position=1878, PM Reset Position=60, Z Follows=50
CURA SETTINGS: Print Speed =90, Initial Layer Height=0.1mm, Built Plate Adhesion Type= Brim=2.5mm.
Also I get these results no matter the resin I use (look for the attached picture). I mean the cylinders and not only are moved close to the door. Any suggestions or thoughts?

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#5

have you went through the advance calibration to make sure your galvo and laser is positioned correctly?

Advance Moai calibration guide:

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#6

Hi! Yes I have done the advance calibration twice but on the first one, the instructions were telling me to place the shorter spacing of the printed PDF – calibration-circle closest to the door , when in a newer similar document it was pointing to the opposite side i.e : closest to the z-axis. Doing the calibration based on the second scenario, solved the whole printing area displacement to the door, but has no effect to the skewed problem as I’m still trying to print with the NextDent (purple) resin on 50 & 25 um. As it is seen in the picture below for many objects that I’ve printed on different speeds, the skew problem is obvious and especially when printing on 25um. As the skew distortion is towards the door, when I change the PM Reset Position=40 and the Z-Follows=40, the side at which the distortion takes place changes to the opposite i.e.the back. I have been trying with values in between but it doesn’t get to the desired level. So here are some questions:
The parameters with which I can play are relevant limited to those? :  Laser Power,  PM Reset Position, Z-Follows and from Cura Settings, only the proposed default parameters for the Moai, or can I add others too? For Cura I know that I can add more settings for the .gcode file, but will these have any effect on my printings?
What macklebee says is right, but I suppose that you haven’t tried all the available resins, and the given list with the proposed resins and Settings is only for the ones that you had successful results. Could you also make a list of the resins that you’ve tried to print with, but couldn’t get decent results?
Do you get from my descriptions the assumption that the problem is due to the resin type or that I should play more with specific parameters on the printer and cura, in order to succeed? You see, as I will have this problem solved, I’ll be able to move to another resin type.
Finally could it be a problem related to the galvos as they may have been displaced during shipment?
Thanks!

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#7

This is a shift on the Z axis so it should have nothing to do with galvo. This kind of shift is usually built plate or vat not secured. The leveling number looks good.

Do you still have some peopoly resins left? Can you swap back and do a quick test and see if that looks good.

these are the checkup to make sure key screws are locked down:
wiki.peopoly.net/doku.php?id=moai-checkup

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#8

Hi! Yes, I still have some Peopoly resin to test with and this is what I did. After I double checked all the screws to be tight, redid the z-leveling to a freshly new vat and used the DIY-gcode (which builds at 100um), the four cylinders are all skewed towards the door and a little bit to the left of the printer. I also played a lot with the PM Reset Position & Z-Follows but nothing…Its weird because at the very beginning I could at least print the DIY-gcode and the test-ring, quite proper. Now I’ll try to raise the laser power as someone else from the forum said that he solved this issue by doing that, and I’ll upload more relevant pictures. Any farther steps to follow?

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#9

So you printed 4 cylinders using our own resin with default setting and it is still tilted.

Since your level numbers looks good, power setting is not recommended to be changed. If it is not sticking, something is affecting the light. Check the protective glass on top of galvo, galvo mirrors and the vat to see if anything is damaged on it.

let’s solve the sticking to plate issue before moving to next.

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#10

Hi, I need to add my problems to this post. The sylinders are good in hight, 10,80±0,05. I have done the advanced levelling procedure and the two rings are pretty my dead on the center of the print-out. Still, its very skewed prints as you can judge by looking at the pictures below. I have recently cleaned the protective glass over the galvo, which I fastened with TEC-7. I wonder if this might be the cause though, so I might take it off to check if this is tilted and then causes the skewedness. If that is the case, there should be some warning on the issue of fastening the protective glass, and something you might want to address in coming updates… I’ll come back to you on this as soon as I have tried printing without the protective glass.

They are all tilting towards the left side.

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#11

Did you make sure that the build plate was tightly fastened when you printed? The one time I had it skew like that, the build plate moved because it was slightly loose

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#12

Unfortunately it happens every time for me,but I will take your suggestion into account, for sure!

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#13

When you assembled the printer did you check the bolts on the Z-axis trolley? That can cause a similar behavior to a loose build plate.

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#14

I was having this issue as well on some of my cylindrical shaped parts. I was hand tightening the build plate.

I have a fdm machine as well so I printed the spanner from thingiverse. Now that I am able to snug it down, my problem has vanished.

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#15

Thanks, I just discovered that whole z-axis trolley was skewed. So I have tried to level it now, which means that I need to the whole leveling thing anew for the vat…Think this is the cause of the problem. I’ll let you know when I get the whole thing leveled and do another round of printing/leveling

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#16

Hi! Tried to tighten it as hard as I could, but have discovered that the error was in the z-axis trolley, which was very skewed…Thanks for the tip anyhow!

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#17

for skewed print or random layer shift

do a quick check up:

Moai Checkup guide
http://wiki.peopoly.net/doku.php?id=moai-checkup

and make sure everything is tighten up.

also bad leveling can cause skewed prints as well

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#18

Hi again! Sorry, but no luck. I have very carefully gone through the Moai Checkuo guide. I did correct the tilt-motor somewhat and thought that it would do the trick, but it did not change anything in particular. I have uploaded some pictures so that you can get a closer look. If you look at the reading of the micrometer, you will see that the “bolts” are between 10.73 and 10.92. I could fine-tune it more, of course - but that does not do anything to the skewedness, I am afraid. I also read another thread here that there was a problem with settings in Cura. Well, I have not used Cura for these - so I don’t think that would be the problem - but maybe its good to consider if there’s a software issue, and not mechanical? I really don’t know were to go from now on…

The rod indicates the direction of the plate, it is where built plate connects inside the printer

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#19

Try turning off the Z follows, set it to zero. Then post some new pictures with them on the build plate.

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#20

Ok, I’ll try it out. Back in a bit…

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