How to achieve a fully filled in first layer
 

How to achieve a fully filled in first layer  

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Bonjipoo
(@ben-9)
Active Member

Ive been trying to achieve a fully filled in first layer.  When i say that i mean absolutely smooth first layer on the smooth sheet or no lines visible on the textured sheet.  Have spent hours with different filaments and different z heights to try to achieve a fully filled first layer but without luck.

Often the first layer is perfect near the perimeters but when the nozzle move across the centre of the print lines appear.
Its as if near the perimeter the filament is fused to the previous line but when it moves toward the centre of the part the filament isn't.  Maybe this is because near the perimeters the previous line of filament still carries some temperature so they squish together perfectly but in the centre its cooled enough so only the newly extruded line squishes.

 

Have tried increasing extrusion multiplier until stringing and also read about reducing extrusion width on first layer which helps a lot as it effectively increases the resolution.  More lines but they are smaller.  Dont think you can increase extrusion on just the first layer?

Any thoughts on this would be great. An any pictures of perfect first layer would also be great to see.

Best Answer by bobstro:

Posted by: @ben-9

Ive been trying to achieve a fully filled in first layer.  When i say that i mean absolutely smooth first layer on the smooth sheet or no lines visible on the textured sheet.  Have spent hours with different filaments and different z heights to try to achieve a fully filled first layer but without luck.

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 on-board 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. 

Often the first layer is perfect near the perimeters but when the nozzle move across the centre of the print lines appear.
Its as if near the perimeter the filament is fused to the previous line but when it moves toward the centre of the part the filament isn't.  Maybe this is because near the perimeters the previous line of filament still carries some temperature so they squish together perfectly but in the centre its cooled enough so only the newly extruded line squishes.

I think this is a separate issue. Troubleshoot them one at a time:

  • The gaps between 1st layer extrusions indicates your Live-Z setting it too high (not negative enough). Use Jeff's "Life Adjust" calibration print to adjust it until you get that even top layer with no gaps. When you lift the 75x75 square, it should come off as one piece and not be easy to tug apart.
  • The line as the nozzle moves across the bed is addressed with z-lift. You can adjust this under Printer Settings->Extruder 1->Retractions->Lift Z. This will raise the nozzle before moving over previously printed parts, and is used to reduce that scarring effect.
  • Although you can adjust z-lift, you should try to figure out why it's happening. It's likely a bit of ooze is dripping out of the nozzle and gets dragged across the top surfaces. What filament are you using? If not using a Prusa filament or one that exactly matches a filament profile, it's likely you need to tune the filament profile. It's easy to do.

Have tried increasing extrusion multiplier until stringing and also read about reducing extrusion width on first layer which helps a lot as it effectively increases the resolution.  More lines but they are smaller.  Dont think you can increase extrusion on just the first layer?

I think this explains your scarring issue. Do not try to fix 1st layer issues with a lot of over-extrusion. Any over-extrusion will carry into your entire print and result in poor vertical walls and horrid supports. Set the extrusion multiplier to 1 for the 1st layer Live-Z adjustments.

Get your Live-Z right 1st. Then look at Prusa's guide on calibrating your extrusion multiplier for your filament. Filament gets runnier as it is heated, so you might consider reducing your nozzle temp 5-10C. What filament are you using and what temperatures are you printing with?

Any thoughts on this would be great. An any pictures of perfect first layer would also be great to see.

I've got some notes here on Live-Z calibration (using Jeff's approach) and more notes on extrusion multiplier calibration here

Posted : 28/07/2020 9:18 pm
jsw
 jsw
(@jsw)
Honorable Member

I usually do not have any obvious lines on the textured sheet.

On the smooth sheet, I've done the 3x3 Z calibration and I'm looking at a print now, and if you look closely you can see the perimeter margin, but it's not obvious from a foot away.  I just tried to take a quick photo of it to post here but it does not show up very well at all in the photo.

Often times lowering the Z will fill in lines.

This post was modified 2 months ago by jsw
Posted : 28/07/2020 9:27 pm
Bonjipoo
(@ben-9)
Active Member

@jsw

Yeah. Thanks for that.  I wondered if increased bed temperatures would help?

Posted : 28/07/2020 9:45 pm
jsw
 jsw
(@jsw)
Honorable Member

I'm assuming PLA here.  Some say that increasing the bed temp to maybe 70C or so helps with adhesion.  My experience is that it does not really make that much difference, if any.

Posted : 28/07/2020 9:47 pm
Bonjipoo
(@ben-9)
Active Member

@jsw

Yes I'm currently using PLA.  You see i know it is possible because the Prusa mini LCD cover is printed with a textured sheet and there are no lines on the surface at all although that is printed with PETG which i have also tried.

Posted : 29/07/2020 11:21 am
bobstro
(@bobstro)
Illustrious Member
Posted by: @ben-9

Ive been trying to achieve a fully filled in first layer.  When i say that i mean absolutely smooth first layer on the smooth sheet or no lines visible on the textured sheet.  Have spent hours with different filaments and different z heights to try to achieve a fully filled first layer but without luck.

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 on-board 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. 

Often the first layer is perfect near the perimeters but when the nozzle move across the centre of the print lines appear.
Its as if near the perimeter the filament is fused to the previous line but when it moves toward the centre of the part the filament isn't.  Maybe this is because near the perimeters the previous line of filament still carries some temperature so they squish together perfectly but in the centre its cooled enough so only the newly extruded line squishes.

I think this is a separate issue. Troubleshoot them one at a time:

  • The gaps between 1st layer extrusions indicates your Live-Z setting it too high (not negative enough). Use Jeff's "Life Adjust" calibration print to adjust it until you get that even top layer with no gaps. When you lift the 75x75 square, it should come off as one piece and not be easy to tug apart.
  • The line as the nozzle moves across the bed is addressed with z-lift. You can adjust this under Printer Settings->Extruder 1->Retractions->Lift Z. This will raise the nozzle before moving over previously printed parts, and is used to reduce that scarring effect.
  • Although you can adjust z-lift, you should try to figure out why it's happening. It's likely a bit of ooze is dripping out of the nozzle and gets dragged across the top surfaces. What filament are you using? If not using a Prusa filament or one that exactly matches a filament profile, it's likely you need to tune the filament profile. It's easy to do.

Have tried increasing extrusion multiplier until stringing and also read about reducing extrusion width on first layer which helps a lot as it effectively increases the resolution.  More lines but they are smaller.  Dont think you can increase extrusion on just the first layer?

I think this explains your scarring issue. Do not try to fix 1st layer issues with a lot of over-extrusion. Any over-extrusion will carry into your entire print and result in poor vertical walls and horrid supports. Set the extrusion multiplier to 1 for the 1st layer Live-Z adjustments.

Get your Live-Z right 1st. Then look at Prusa's guide on calibrating your extrusion multiplier for your filament. Filament gets runnier as it is heated, so you might consider reducing your nozzle temp 5-10C. What filament are you using and what temperatures are you printing with?

Any thoughts on this would be great. An any pictures of perfect first layer would also be great to see.

I've got some notes here on Live-Z calibration (using Jeff's approach) and more notes on extrusion multiplier calibration here

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 : 29/07/2020 4:20 pm
geoper2 liked
Bonjipoo
(@ben-9)
Active Member

@bobstro

Thank you for your indeptht reply.  I have actually been using the life adjust method.  Its much better i agree but it think my problem has more been identifying when the nozzle is at the correct height setting.  This takes some experience i guess.  

I am currently using an expensive ColorFabb Colour on Demand PLA.  It should be good stuff and does seem to be. Have also used Prusament which is great but not enough colors. 

Ive had some success today and it seems stupid when i say it but i realised that one way to remove the lines was to remove the lines and use a different pattern for the bottom infill. See the picture for before and after.  The best pattern in my mind to really break up the stripes was the Hilbert pattern.  Here are the results.  An almost perfect bottom layer on a textured sheet although one corner has lifted which could still indicate the Z is too high.

 

On the right the original issue using rectilinear pattern.  Its fully filled in.  One corner has lifted and stripes but otherwise ok.
On the left the last print using the Hilbert Pattern.  Fully filled in. One corner lifted.  Almost perfect.

Not sure if this would work with the smooth sheet or if this is just cheating.

Posted : 29/07/2020 5:29 pm
bobstro
(@bobstro)
Illustrious Member
Posted by: @ben-9

[...] I am currently using an expensive ColorFabb Colour on Demand PLA.  It should be good stuff and does seem to be. Have also used Prusament which is great but not enough colors. 

Oh man, don't use the good stuff for these calibration prints! Basic PLA is fine. Once you get your Live-Z set correctly, you can make fine adjustments for specific filaments with the extrusion multiplier and filament diameter settings in your filament settings profile.

Ive had some success today and it seems stupid when i say it but i realised that one way to remove the lines was to remove the lines and use a different pattern for the bottom infill.

That works, but you want "worst case" for calibration. Stick to rectilinear using the "Life Adjust" method.

See the picture for before and after.  The best pattern in my mind to really break up the stripes was the Hilbert pattern.  Here are the results.  An almost perfect bottom layer on a textured sheet although one corner has lifted which could still indicate the Z is too high.

Wait a sec. If only one corner is lifting, that more than likely is an adhesion issue, not Live-Z. Particularly if the lifted bit printed correctly. I can't stress the importance of adhesion enough. You need a really clean bed THEN do Live-Z calibration.

On the right the original issue using rectilinear pattern.  Its fully filled in.  One corner has lifted and stripes but otherwise ok.
On the left the last print using the Hilbert Pattern.  Fully filled in. One corner lifted.  Almost perfect.

Play with those patterns once you get a good Live-Z. You're close.

Not sure if this would work with the smooth sheet or if this is just cheating.

Many people, myself included, have poor luck with PLA adhesion on the textured sheet. A good cleaning with dish soap under a hot kitchen sink can help in some cases. If you have the option, I'd recommend trying it on a smooth sheet first. Once you see Live-Z done properly, you'll recognize it quickly and be able to adjust it in seconds. Get it working on the smooth first, then try to repeat the process on the textured sheet.

Stick with it. Realizing that these 2 steps were critical was a real turning point for me early on. Joan will set you on the right path! Good luck with it.

 

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 : 29/07/2020 5:41 pm
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