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First layer problems on wide print  

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Tooqui
(@tooqui)
New Member
First layer problems on wide print

Hi All,

Actually this is not about a first print as I have been using my prusa MK3S+ for some time with good results. Situation is I have only printed kind of small prints, like 10x10 cm or so max (on XY dimensions).

I was trying to print several smaller prints at the same time using nearly all the surface of the steel sheet and then I found a disgrace. Outer pieces just won´t stick to bed per areas.

I started my journey on forums, blogs and, I could probably say hell as well. 

- I am not using the nylock mod. I use the standard spacers provided. 

- I am using the steel sheet not the powder coated one.

- I have run the mesh bed levelling up to 7x7 and 5 retries

- I have this result (which doesn't look very good I am afraid)  => https://ibb.co/zJLSYb9

- I can print a 60x60x0,1 square in  the center without any issues and good 1st layer in my opinion

- I tried to print the 3x3 advanced levelling print and the disaster came in. => https://ibb.co/0QH5RKM

Some areas it prints some other doesn't.  I have tried to manually change the first layer z value but no matter what I do can not get even results across the surface.

I have read about the bed level correction values in FW but I am concerned about the proper orthogonal printing since per G81 results I have a 0,5mm deviation corner to corner and I am unsure the printer can manage that properly. At 0,15 layer height it means more than 3 layers depending on the  position.

Any proper help would be appreciated.

PS: Yes, I am also reading about the nylock mod but also unsure if this is needed at all these days. If so, prusa would have designed the bed that way not with spacers right?

 

Thank you.

 

This topic was modified 2 months ago 2 times by Tooqui
Posted : 21/07/2021 5:37 pm
Dan Rogers
(@dan-rogers)
Noble Member
Start with a clean bed

Before you go off and try and make a bed modification - I'd recommend a couple of steps.

1.  Soap and water the steel sheet with a mild, scent free dish soap.  Hot water, use a scrubby.  Get that sucker clean.  Then only handle the edges.  This is 99% of weird bed won't stick issues.

2.  Re-tighten your bed.  Loosen the little cone-headed screws that hold the print bed to the bed frame (not remove, just loosen).  Then heat the bed to 260 with preheat.  Be careful from here on things are quite hot.  Then tighten the screws in two passes (a little tight, then tighter)  in the following order while the bed is hot.

Center screw.  Back Left.  Front Right.  Back Right, Front Left.  Center back.  Center Front.  Center Left.  Center Right.

Tighten in two passes.

Let it cool.

Try now.

Posted : 22/07/2021 7:19 am
Diem
 Diem
(@diem)
Noble Member

I agree with @dan-rogers, begin with a thorough wash - use plenty of HOT water, and this may be enought for non critical prints.

Cheerio,

Posted : 22/07/2021 9:32 am
JoanTabb
(@joantabb)
Moderator
adhesion

I also enable 7x7 mesh bed levelling, and use Life adjust Z my way, I also enable 7x7 mesh bed levelling, and use Life adjust Z my way, 
and run the heatbed at 60 to 70C for PLA. 

regards Joan

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 : 22/07/2021 1:34 pm
Tooqui
(@tooqui)
New Member
Topic starter answered:
On the way back to print

Hi All,

Thank you for your input. I followed @dan-rogers recommendations and also contacted support. 

Basically I had to re-do the installation of the heatbed screws and so on on 80º as 260º seemed to be a bit hotter than average 😉

After that re-calibrate XYZ (the paper thing you know) run first layer, print central square 60x60, printed 3x3.

On support they confirmed my bed had a nasty surface and pointed me to the bed level correction. I also asked them about nilock mod and they did not recommend. 

So now I am here => https://help.prusa3d.com/en/article/bed-level-correction_2267

My results are far way better now => https://ibb.co/whm6VJ0

yet not really perfect It is challenging combining the Z calibration (for center) together with sides bed correction as one single step actually affects how overall 3x3 print results. I am referring in my case going from -1.345 to -1.352 and just on decimal change on the correction levels.  CHANGE ONE VALUE AT A TIME AND PRINT A TEST EVERY TIME.

anyway after this situation what I can recommend:

- Start from scratch don't start jumping from solution to solution because you will end up lost and screwed.

- Patience

- WRITE DOWN the test method you are to follow, and follow it. Make a note of results with marker on actual test prints. Do not discard them.

- always go one step further (on values) when you not sure if good or bad so you can choose the best result and hence the value your machine need.

- Why not again PATIENCE and METHOD

 

Thank you all.

Posted : 23/07/2021 7:38 am
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