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Does extrusion width affect flow / multiplier?

Posted: Sat Oct 20, 2018 8:46 am
by martin1454
So there is a little bit of gap between the lines of my solid infill - If I change the extrusion width from 0.48mm to 0.45 it looks really good - But does changing the extrusion width change the flow / gcode or only how close the lines are near to each other.

Re: Does extrusion width affect flow / multiplier?

Posted: Sat Oct 20, 2018 10:24 am
by airscapes
That would not be the correct way to solve the issue of gaps between extrude lines
There are a number of things that will cause your issue. If all are correct you will not have gaps.
1 Starting height too high preventing bead of plastic from squishing (technical term) down as flat as it should be (layer height
2. Filament not really 1.75mm, you should measure that with and accurate caliper to make sure it is correct and does not change as roll is used
3. Extrusion multiplier is not set correct.

The extrusion width is the width of plastic not the gap.. so if the software thinks the plastic is .48 wide it is going to allow just enough room so each line of .48 will contact the one before leaving no gaps. So if anything else prevent the line from being .48 you get a gap.

download the attached single wall square, set the allow single wall and allow single extrude fill on the advance tab and print the square and your extrude width to .45 (the width or the model wall as designed) and layer height .2 (10 layers to reach 2mm tall). Using an accurate digital caliper measure the wall height on all 4 sides, it should be 2mm tall. If it is taller then your starting height is too high if it is shorter than the starting height is too close
measure the wall thickness. It should be .45 mm think. Too thick reduce extrusion multiplier, too thin, increase it. Only go 1 or 2 clicks at a time.

If the filament thickness changes a lot, say 1.75 1.73 1.72 1.73 1.72 1.71 etc.. try setting the thinness in the other tab to 1.73 then do the above calibration. I have found I get better results telling the slicer the size of the filament rather than leaving it at 1.75 and just cranking up the Extrusion multiplier when dealing with inconsistent thickness.
26x26x2x.45mm.stl
(1.64 KiB) Downloaded 106 times

Re: Does extrusion width affect flow / multiplier?

Posted: Sat Oct 20, 2018 12:37 pm
by martin1454
airscapes wrote: That would not be the correct way to solve the issue of gaps between extrude lines
There are a number of things that will cause your issue. If all are correct you will not have gaps.
1 Starting height too high preventing bead of plastic from squishing (technical term) down as flat as it should be (layer height
2. Filament not really 1.75mm, you should measure that with and accurate caliper to make sure it is correct and does not change as roll is used
3. Extrusion multiplier is not set correct.

The extrusion width is the width of plastic not the gap.. so if the software thinks the plastic is .48 wide it is going to allow just enough room so each line of .48 will contact the one before leaving no gaps. So if anything else prevent the line from being .48 you get a gap.

download the attached single wall square, set the allow single wall and allow single extrude fill on the advance tab and print the square and your extrude width to .45 (the width or the model wall as designed) and layer height .2 (10 layers to reach 2mm tall). Using an accurate digital caliper measure the wall height on all 4 sides, it should be 2mm tall. If it is taller then your starting height is too high if it is shorter than the starting height is too close
measure the wall thickness. It should be .45 mm think. Too thick reduce extrusion multiplier, too thin, increase it. Only go 1 or 2 clicks at a time.

If the filament thickness changes a lot, say 1.75 1.73 1.72 1.73 1.72 1.71 etc.. try setting the thinness in the other tab to 1.73 then do the above calibration. I have found I get better results telling the slicer the size of the filament rather than leaving it at 1.75 and just cranking up the Extrusion multiplier when dealing with inconsistent thickness.
26x26x2x.45mm.stl
I tried to calibrate a single wall cube and with an extrusion multiplier of 0,9 i Got a 0,48mm wall, but with the nozzle size set to auto (0,48) the top and bottom layer have quiet large gaps (even through my side walls are 0,48mm)
For my first layer - if i go any lower, I get the type of artifact you get on a too low layer

Re: Does extrusion width affect flow / multiplier?

Posted: Sat Oct 20, 2018 12:44 pm
by airscapes
What is the nozzle size? The Extrusion width should be no smaller than the nozzle size and preferably the rule of thumb is 1.2x larger than the nozzle size as that is what S3D sets the extrusion width to if using Auto.

Lets back up, set you nozzle size to the actual size of the nozzle and choose auto and tell me what it sets the Extrusion width to and I will make a new model with that wall thickness. Then you can follow the calibration routine and see what you get.

Re: Does extrusion width affect flow / multiplier?

Posted: Sat Oct 20, 2018 1:12 pm
by martin1454
airscapes wrote:
Sat Oct 20, 2018 12:44 pm
What is the nozzle size? The Extrusion width should be no smaller than the nozzle size and preferably the rule of thumb is 1.2x larger than the nozzle size as that is what S3D sets the extrusion width to if using Auto.

Lets back up, set you nozzle size to the actual size of the nozzle and choose auto and tell me what it sets the Extrusion width to and I will make a new model with that wall thickness. Then you can follow the calibration routine and see what you get.
My nozzle is 0,4mm so auto width is 0,48

Re: Does extrusion width affect flow / multiplier?

Posted: Sat Oct 20, 2018 1:28 pm
by airscapes
The .45 should work just fine but here is the .48
Set Nozzle size to .4, E Width Auto, and see what you get.. should be 2mm tall and .48 thick.. i
26x26x2x.48mm.stl
(1.64 KiB) Downloaded 89 times
If you want to use .45 E width, you leave the nozzle set to .4 and use the manual option for E Width and enter .45

Re: Does extrusion width affect flow / multiplier?

Posted: Sun Oct 21, 2018 7:53 am
by martin1454
Huh, found the problem (at least for the bottom layer)

Had set "First layer width" to 110% because I thought it would increase the flow to make wider traces, but it does increase the space between tracks - Still in progress of the print to see if it fixes my top layer also.

Re: Does extrusion width affect flow / multiplier?

Posted: Sun Oct 21, 2018 11:01 am
by airscapes
First layer 90% was default for me and works very well.. Assumed that was default for all but maybe not.