Chadd
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Re: First print layers density question

Tue Jun 09, 2015 11:28 pm

jimc wrote:hey chadd i know we were talking on the other forum about this. wanted to confirm something. when you set the first layer to 100% width your saying it shows normal extrusion in the print preview of the first layer BUT if you set the width to 150% then in the preview its showing you the same size extrusions but putting a space between the lines? if so can you post a factory file of a model you are seeing this problem with?

Yes that is what happens, I have been playing around with it again today and oddly enough if I set the "first layer width" to less than 100% then the first layer is more dense than it is at 100% and there are no gaps between the extrusions.

JoeJ
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Re: First print layers density question

Wed Jun 10, 2015 6:30 am

Chadd wrote:Instead of putting 130% material into the space that 100% would have gone into S3D spreads the extrusion out and in turn will create voids between the extrusion. So it does the exact opposite of what other slicers do.
You're using some odd wording here, so let me clarify things.

I am assuming when you say "130% extrusion" you mean that you have adjusted your first layer WIDTH to be 130%. In that case, yes, the width of your extrusions are increased and thus they will be spread out more. S3D will also extrude more plastic to account for this. If you adjusted the first layer width and it DIDN'T increase the width, this setting wouldn't make any sense (any you'd also probably get a lot of over-extrusion). So first layer width extrudes more plastic so that it can create thicker lines.

Another settings is the first layer height. This will adjust the thickness of your first layer. For example, if you set it to 200%, it will extrude twice as much plastic and create a layer that is twice as thick. This is particularly helpful when printing at fine layer heights such as 0.1mm.

In my mind, both of these settings work exactly as I would expect. If you are needing to extrude a lot more plastic to get a normal layer to fill in properly, then your nozzle is too far away from the build plate. That's probably why you see so many other comments on here talking about the Z-offset or leveling the bed.

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ClassicGOD
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Re: First print layers density question

Wed Aug 12, 2015 2:47 pm

JoeJ wrote:In my mind, both of these settings work exactly as I would expect. If you are needing to extrude a lot more plastic to get a normal layer to fill in properly, then your nozzle is too far away from the build plate. That's probably why you see so many other comments on here talking about the Z-offset or leveling the bed.
I just found this thread because I encountered the same problem. S3D is not extruding the correct amount of plastic for the set first layer width.
I've spent some time calibrating my printer to be spot on 0,3mm height for the first layer, then I set 0,2mm Primary Layer Height and 150% First Layer Height. Once that was done I created few processes with only one difference - First Layer Width from 110% to 200%. I measured my filament to make sure that there are no significant differences in width in a used portion. The results: http://uploads.classicgod.org/s3d_first_layer.jpg this is not the correct behavior IMO.
Printrbot Simple Metal with E3D-v6 hot end

JoeJ
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Re: First print layers density question

Thu Aug 13, 2015 6:00 am

Why don't you post the gcode from those prints? It will be pretty easy to look through it and tell you if the software is properly extruding twice as much plastic as you would expect if the first layer width went to 200%. If so, then the gcode is correct, and it's likely related to bed positioning.

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ClassicGOD
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Re: First print layers density question

Thu Aug 13, 2015 7:21 am

JoeJ wrote:Why don't you post the gcode from those prints? It will be pretty easy to look through it and tell you if the software is properly extruding twice as much plastic as you would expect if the first layer width went to 200%. If so, then the gcode is correct, and it's likely related to bed positioning.
GCode: http://uploads.classicgod.org/layer_test.gcode

According to the maths outlined here: http://manual.slic3r.org/advanced/flow-math the flow should be ~2,2 times higher. I wouldn't be surprised if S3D extruded exactly 2 times the material (with the width set to 200%) but this is not enough because the extrusion is not a rectangle.

[EDIT]
I don't think this is a bed distance issue - the pictured layers are 0.3mm thick, just as they are supposed to be. If I get closer to the bed the first layer will be to thin resulting in adhesion problems (extrusions deforming and lifting extrusions next to them due to widening of the extrusion but not the path) and the print won't be dimensionally accurate.

Don't get me wrong - It's not bothering me too much - I'll just stick to under 125% width as I get perfect layers like that (just a little bit lower adhesion) but it simply surprised me ;) The best solution would be to introduce first layer extrusion multiplier - problem solved ;) .
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Rebekah_harper
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Re: First print layers density question

Thu Aug 13, 2015 10:36 am

thought I'd just say this.

I level my build plate with all nozzles hot and the bed hot.

even then I still have to adjust the Z height offset in the Gcode panel. I have neve had it where the level on my Gcode is 0 always -0.xx

I wouldn't go for any extra extrusion to make up the gap it opens up to all sorts of issues in the long run.

it's worth just playing around with the height settings in the Gcode panel.

KC_703
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Re: First print layers density question

Fri Aug 14, 2015 12:27 am

Just found this thread... Regarding the adjustment of the Z-offset to increase the "squash", it doesn't work for a print surface like PEI / Ultem (which happens to be on the OP's TAZ5). When the nozzle is too close to the bed, ABS and PLA brilliantly bonds too well to the surface.

So the OP's solution of "tricking" S3D through the extreme "First Layer Height %" may be the best solution. Just tried this with 3 calibration cubes varying the first layer heights by 100, 200 and 300, and did a second run varying the width by the same percentages. Varying the width left gaps between the filament paths and the increasing the first layer height does eventually produce a solid first layer.

Nice find OP

jeevesme@hotmail.com
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Re: First print layers density question

Tue Dec 15, 2015 9:55 am

So would these statements be true then?

If the First Layer Height is Under 100%, it just decreases the layer height and does not change the amount of filament extruded.
If the First Layer Height is Over 100%, it will increase the layer height AND extrude more filament.
If the First Layer Width is Under 100%, it will decrease the amount of filament extruded.
If the First Layer Width is Over 100%, it will increase the amount of filament extruded.

maddavo
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Re: First print layers density question

Thu Dec 17, 2015 8:56 pm

jeevesme@hotmail.com wrote:So would these statements be true then?

If the First Layer Width is Under 100%, it will decrease the amount of filament extruded.
If the First Layer Width is Over 100%, it will increase the amount of filament extruded.
Not sure about the other two statements, but w.r.t. the above my understanding is that is NOT the case.

My understanding of the S3D's First Layer Width is the distance between adjacent infill lines. Increasing the FLW will make the adjacent infill further apart AND extrude more filament to make the lines wider - proportionally. So the nett effect is that you have the same amount of filament going into the first layer. This is NOT how Cura or Sli3r work and I think this where some misnomer/miscommunication is occurring.

Cura and Sli3r have settings for adjusting the extruded filament for the first layer - thereby adjusting the width of the lines for the first layer. ie: First Layer Width.

So "First Layer Width (Cura/Slic3r)" <> "First Layer Width (S3D)"

From all the settings I have seen in S3D, there is no setting which will adjust the amount of extruded filament for just the first layer. If there is, then please point me to it because I am tearing my hair out. At the moment I am setting my flow rate manually on my printer when I print the first layer and then manually setting back to 100% when it gets to the 2nd layer - very tedious. AND if I forget to go and dial it back to 100% I get a messy blob of a failed print.

Clearly there is a need to be able to adjust the extrusion multiplier for the first layer.

CompoundCarl
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Re: First print layers density question

Fri Dec 18, 2015 5:58 am

If you have to adjust the extrusion amount for the first layer alone, then your print isn't starting at the correct height. There's no other reason you would need to adjust the first layer flow rate unless the nozzle was not starting at the correct height.

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