Weird pulling / waves on first layer  

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DadOf6
(@dadof6)
Active Member

Hello!

Struggling a bit with what I figured would be a simple print.  It's a simple case for Dig-Uno.  The first layer for the case is just a big flat piece.

I am using MatterHackers Build PLA for this.

Best Answer by bobstro:

Posted by: @dadof6

[...] I get a nice square, and it sticks, but when you pull it up the extrusions don't touch one another, but they stick to the bed.  

That's an indication that you're still too high. Once Live-Z is set properly, the square should peel up as one piece and not pull apart easily. You should be able to pull it off the sheet and view a light through it. If I'm impatient and pull it up while still hot, it will stretch but not pull apart at the extrusion lines. 

I'd reduce Live-Z by 0.06-0.08 and try the square again.

 

Posted : 03/03/2021 3:23 pm
DadOf6
(@dadof6)
Active Member

Hmm I am not sure why all of my details did not end up in this post. Let me try again. I will attach pics of everything I describe.

I don't think overall that I have an adhesion issue (except for the waves).  It is fine on the edges just gets worse in the middle.  The lid works just fine.  It's not solid.

I tried a number of things.  Slowing nozzle speed, speeding up nozzle.  Adjusting live Z.  Higher bed temp, lower bed temp.  Higher nozzle temp, lower nozzle temp.

The next things I want to try are turning the fan on the first layer at 100%, or changing width/depth of first layer. 

 

Posted : 03/03/2021 3:53 pm
bobstro
(@bobstro)
Illustrious Member

I think your Live-Z is still a bit high. You're not getting good adhesion. It's always tricky to try to interpret pics though.

If you have not already done so, try using Jeff Jordan's "Life Adjust" procedure for calibrating your Live-Z setting. It is much easier to use and understand than the onboard routine and much easier to make mid-print adjustments accurately with. In general, start high (less negative) and work lower (more negative) in large increments (e.g. 0.1mm) until the filament starts to stick on its own. When you've got your Live-Z setting adjusted properly, you should be able to gently rub the extruded lines on the PEI surface without dislodging them.  Then start lowering (more negative) the level until there are no gaps between layers. You should not be able to peel the lines apart after printing, but the top should be regular. 
My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 03/03/2021 3:59 pm
Dan Rogers
(@dan-rogers)
Prominent Member

I agree w/bobstro - those lines are barely squished at all.

 

Posted : 03/03/2021 4:15 pm
DadOf6
(@dadof6)
Active Member

@bobstro

Thanks - yes I did try that as well - a few times.  I get a nice square, and it sticks, but when you pull it up the extrusions don't touch one another, but they stick to the bed.  I assume that's due to first layer thickness/width settings on LiveAdjust vs. the dig-uno case.  I don't have a photo result of LiveAdjust right now - I'll have to print another one and send it.

Posted : 03/03/2021 4:34 pm
bobstro
(@bobstro)
Illustrious Member
Posted by: @dadof6

[...] I get a nice square, and it sticks, but when you pull it up the extrusions don't touch one another, but they stick to the bed.  

That's an indication that you're still too high. Once Live-Z is set properly, the square should peel up as one piece and not pull apart easily. You should be able to pull it off the sheet and view a light through it. If I'm impatient and pull it up while still hot, it will stretch but not pull apart at the extrusion lines. 

I'd reduce Live-Z by 0.06-0.08 and try the square again.

 

My notes and disclaimers on 3D printing and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan...
Posted : 03/03/2021 4:40 pm
DadOf6
(@dadof6)
Active Member

Thanks @bobstro & @dan-rogers!  Yes, I was being too delicate in my live-z.  When I'd initially done it with the smooth sheet I ended up getting marks on the sheet like I had hit the nozzle on it, so I was rather tentative.  I redid the Live Adjust and was more aggressive.  Not perfect yet but no more waves!  Thanks again for your quick responses!

Posted : 03/03/2021 10:51 pm
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