First layer Height Width no changing extruder flow

[Benito]

Three first layer issues that I am experiencing:

1) First layer height have read does not affect extruder flow rate. It is suggested for better bed adhesion to lower Height to 90%, thus same extruder flow going into a tighter height results in the bead to spread on the bed. But also read that settings of 200% Height would help in adhesion for thinner layers, but if the extruder is not compensating all you get is the very bottom of the bead to just touch the bed....worthless.

2) When you increase First Layer Width to say 150% you can see on the screen the 1st layer traces are fewer, wider apart and show as being fatter but when it prints the traces are the same diameter with wide gaps between them. Can really see the issue when you take it to 200% you just get traces that are strings with big gaps. What is the purpose of increasing the width to get a better adhesion if the traces don't touch?

3) When adding a brim to the object they show on screen and print at the normal (non-first layer height & width) thickness. The brim first layer should be affected by the first layer settings. Thus due to the issues with the First Layer Height & Width settings vs. extruder rate, am not getting a good attachment between the brim and outer wall.

Seems like the only way to get a thicker bead to fill in the desired First Layer bead Height and Width setting would be to increase the Extruder Multiplier way up, but this would affect all of the extrusions. If this is the intent of the software, they need to add an extrusion multiplier to the first layer setting box...or better yet make the extruder compensate for the height and width settings automatically.

If I wanted a fatter and taller first layer bead to get better bed adhesion and to compensate for slight bed level issues, I would increase the First Layer Height and Width and the extruder would automatically flow more filament in to fill in the increased area in proportion to the increased desired area. That way once you have your normal extruder multiplier set after calibration one should not have to adjust that setting much at all.

If I need to prevent curling of the first layer(s) and I add a brim it should be affected by the first layer settings so as to have just as much width and height to ensure the same bed adhesion and connection to the print object outer wall.

Hope someone can assist with these issues I am experiencing.

Thank you

Ben

[brian442]

Well first of all, you need to separate the software from the printer itself. You can check the gcode commands that the software is generating to make sure it's creating the correct commands.

I actually checked all 3 of the items you mentioned, and from all the tests I did, the gcode files are actually correct.

1) First layer height of 200% not affecting flowrate - I set the height to 200%, exported the file, and the E-values clearly doubled for moves of the same length, so the software was extruding twice as much plastic, just like I would expect.

2) First layer width to 150% not affecting flowrate - Same as above, I made this change, then it's pretty easy to check the gcode file to see that the lines are spaced further apart, but again, the E-values increased by 50%, just as would be expected. So not only are the lines spaced further apart, but the extruder is also extruding more plastic to fill them in.

3) Skirt and brim not affected by first layer settings - I am also not seeing the same thing you are here. The skirt/brim follows the same first layer height/width that I set above, and it's pretty easy to verify that in the preview.

So you might want to check the gcode files first, as all 3 of the things you mentioned work correctly for me. Of course, if the actual print looks different, there's lots of factors that could affect that like bed leveling, nozzle height, priming, etc.

[Benito]

Brian,

Thank you very much for your detailed response. I did have the three factors that you listed causing the first layer gap issue. After a little filament calibration, Extruder Magnification adjustment and additional bed leveling I can see the proportional adjustment of the extruder flow and finally got a beautiful .1mm layered LED strip bracket for my printer!

Between the gaps I was initially seeing in my print and what is stated on the Simplify3D site, https://www.simplify3d.com/support/arti ... rst-layer/ ,that the extrusion amount is not affected under 100%:

"Percentages under 100% will reduce the height of the layer being printed (with no change to the extrusion amount). For example, if you entered 75%, your first layer height is reduced while your extrusion remains at 100%."

What it does fails to state is how the extrusion is affected above 100%. Would be great if it was updated to say:

"For First Layer Height and Width settings above 100% the extrusion amount increases in proportion to the height and width settings above 100% to fill in the larger extrusion size."

Also I assume the First Layer Width settings is like the Height setting in that below 100% it does not changing the extrusion amount too?

If the guide could be updated to address these two items it would help guide the next person to looking at the issues you pointed out.

The final item is I still see that the Brim itself is not affected by the First Layer Width setting. Attached is the slicer screen shot with a 200% first layer width. You can see that the brim is coming out at the normal spacing and the object at the 200% spacing. But in either case thanks to the 3 corrections you suggested, it is now attaching perfectly.

Thank you again.

Ben

[GeckoBox]

To revive an old thread, I can 100% confirm that first layer width adversely affects a brim. It seems that the extrusion settings are applied, but the XY spacing of each line of brim is not. The affect is that they become tightly packed together and actually adversely affect adhesion.

Here is a picture from my slicer, The first image has first line width at 50%, the second at 300%.