What should be the width of the first layer calibration. with .4mm nozzle?
 
Notifications
Clear all

What should be the width of the first layer calibration. with .4mm nozzle?  

  RSS
jwedwards
(@jwedwards)
New Member
What should be the width of the first layer calibration. with .4mm nozzle?

I I  have the ability to optically measure the width ( not height) of the first layer single line. Can anyone provide me with what should be the proper width? I can measure width to an accuracy of .0065mm

Posted : 02/07/2021 5:53 pm
bobstro
(@bobstro)
Illustrious Member
RE: What should be the width of the first layer calibration. with .4mm nozzle?

The 1st layer extrusions are intended to squish together to form a cohesive sheet for good adhesion. There is no single "correct" value.

You could print a vertical wass one extrusion wide and measure that. It should be close to your set perimeter width.

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 : 02/07/2021 7:46 pm
RedDawg
(@reddawg)
Estimable Member
RE: What should be the width of the first layer calibration. with .4mm nozzle?

The "optimum" width will also differ from filament to filament and between build sheets, smooth/textured/ ambient  temperature, etc, so no, there is not one width that is going to be best for all situations. 

1. "Creativity is the sudden cessation of stupidity." and "Any problem can be solved with the materials in the room." -Edwin Land, inventor of the Polaroid Land Camera. 2. "If I can't fix it, it isn't broken." -Me....
Posted : 02/07/2021 10:40 pm
Leviatank
(@leviatank)
New Member
RE: What should be the width of the first layer calibration. with .4mm nozzle?
Posted by: @reddawg

The "optimum" width will also differ from filament to filament and between build sheets, smooth/textured/ ambient  temperature, etc, so no, there is not one width that is going to be best for all situations. 

Thank you for this post. Good luck.

PrepaidCardStatus...
Posted : 08/07/2021 7:26 am
Durahl
(@durahl)
Trusted Member
I second that Question - In a different way

I recently came across the same question but in instead of the width I was wondering about the height.

Fairly early on after I got my i3 MK3S I immediately changed the stock settings in the profiles Prusa ships within PrusaSlicer so I may have accidentally skipped a moment of revelation?

Anyway... I pretty much always 3D Print with 0.3mm Layer height and 0.6mm width ( on a 0.4mm Nozzle ) as it allows me to get more bearable print times simply by only having to print 2 instead of 3 perimeters while retaining the same strength ( 2x 0.6 = 3x 0.4 ).

Not exactly sure why but for my last project I decided to have the first layer be 3D Printed at 0.2 ( 0.35mm width ) instead of my usual 0.3mm layer height ( and 0.35mm width ) after having two prints fail due to poor adhesion to the PC PEI Print bed - One can easily spot if the first layer, while still printing, is adhering poorly with holes forming between the lines - And the 0.2mm attempt was laid down BEAUTIFULLY even when compared to 0.3 that didn't fail.

So yea... With a 0.1mm difference hardly being perceivable by eye when doing the first layer calibration I too was wondering what the proper height of the square at the end of the Calibration process should read ( for both the Smooth or Powdercoat PEI Sheet ) when measured with Calipers.

Posted : 22/07/2021 10:29 am
jwedwards
(@jwedwards)
New Member
Topic starter answered:
WIDTH LISTED IN PRUSA SLICER.

In Prusa slicer under printsettings>advanced there is a setting for extrusion width. and for a .4mm nozzle the default is .42mm I ended up at about .430mm +/- for a smooth sheet and it seems to work  well. I will say that when measuring with this precision, the line width will vary some but the .430mm is more or less an average.

Posted : 22/07/2021 1:12 pm
bobstro
(@bobstro)
Illustrious Member
The prime line is not generated using the slicer settings
Posted by: @jwedwards

In Prusa slicer under printsettings>advanced there is a setting for extrusion width. and for a .4mm nozzle the default is .42mm I ended up at about .430mm +/- for a smooth sheet and it seems to work  well. I will say that when measuring with this precision, the line width will vary some but the .430mm is more or less an average.

That setting only affects lines generated with the slicer. The prime line is exclusively under the control of your start gcode and does not use the PrusaSlicer settings. You can prove this for yourself. Open up PrusaSlicer and look at the start gcode. With Expert mode enabled, take a look at Printer Settings->Custom G-Code->Start G-Code and locate these lines:

G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E12.5 F1000.0 ; intro line

Change the value after the E parameter. For example, swap the 12.5 and 9.0 values or simply tweak them up or down. You'll notice your prime line width changing with prints made with the modified setting regardless of your extrusion width settings in PrusaSlicer.

If your prime line is indeed changing width, it likely is because of variations in your Live-Z setting and the amount of "squish" applied at lower layers. It has nothing to do with slicer settings and the result is meaningless in terms of tuning. 

 

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 : 23/07/2021 2:10 pm
bobstro
(@bobstro)
Illustrious Member
A few 1st layer considerations
Posted by: @durahl

I recently came across the same question but in instead of the width I was wondering about the height.

[...]

Not exactly sure why but for my last project I decided to have the first layer be 3D Printed at 0.2 ( 0.35mm width ) instead of my usual 0.3mm layer height ( and 0.35mm width ) after having two prints fail due to poor adhesion to the PC PEI Print bed - One can easily spot if the first layer, while still printing, is adhering poorly with holes forming between the lines - And the 0.2mm attempt was laid down BEAUTIFULLY even when compared to 0.3 that didn't fail.

Just to clarify: When @jwedwards mentioned the "first layer single line", it seems to be a description of the prime line. In any case, no further clarification has been provided. Be aware that the prime line itself is printed using entirely different parameters than the rest of your print. It is solely generated in start gcode. Specifically, when the start gcode automatically homes after automatic mesh bed leveling, the nozzle is located at 0.15mm above the bed (according to the PINDA probe). In the default Prusa start gcode, the prime line is printed at this height as there is no Z adjustment before it starts printing. The prime line prints lower than your 1st layer height.

So yea... With a 0.1mm difference hardly being perceivable by eye when doing the first layer calibration I too was wondering what the proper height of the square at the end of the Calibration process should read ( for both the Smooth or Powdercoat PEI Sheet ) when measured with Calipers.

A few factors are possibly causing this:

  • The thicker 1st layer approach was developed to compensate for older printers with far less even beds. It is still common to use thicker 1st layers with those. With the Prusa PEI sheets and automatic mesh bed leveling consistency, you don't need to use a thick 1st layer to work around problems. Not to say you can't or shouldn't use 0.3mm, but it's something to consider.
  • The higher the layer in relation to the nozzle size, the more rounded the extrusion produced. A more rounded extrusion has less surface contact with the surface below (less "squish") so may pop off more easily. You might try printing some single-line extrusions at different heights and poke at them with your finger to confirm.
  • Assuming you're using the same linear speeds, an extrusion at 0.3x0.6mm is going to push out filament at twice the rate of a print at 0.2x0.45mm (9 vs 4.5mm^3/s). This is still within the capacity of the E3D V6 hotend (roughly 11.5mm^3/s for PLA with a 0.4mm nozzle) but it does mean there's less time to heat the filament in the hotend before it's extruded, and less time for it to adhere. You didn't mention your 1st layer speed, but you might try reducing it with a thicker 1st layer.

FWIW - You can't go lower than 0.15mm for your 1st layer on a Mk3 due to the software endstops. You can screw up your Live-Z so 0.15 is actually lower, of course.

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 : 23/07/2021 2:23 pm
Share: