Infill line width

[CM7753 0]

Hi!

 

I'm having issues with infill line width setting in Cura 4.13.1 and Cura 5.0.0 with Ender 3 printer. I have a 0.4 mm nozzle and I am printing with PLA with 200° nozzle temp.

 

If I change just the infill line width to 0.6 or 0.8 mm, than in preview I can clearly sea the change in line width, but on the printed parts the line width stays the same at around 0.4 mm.

 

If I change setting Line width - so that all lines are now 0.8 mm, all the lines are being printed wider. Wall lines are a bit wider, but infill lines are about 0.7 mm.  

 

I printed a lot of test pieces with infill line width set to 0.4; 0.6 or 0.8 mm and they all stay the same.

 

I  was hoping to be able to print stronger parts faster, or at least test if they are stronger. But since the infill line width didn't change my parts got weaker do to less infill actually being produced. Difference in weight of the parts - theoretical and actual, is about 25% less than they should weigh according to preview. 

 

First picture is preview in Cura 4.13.1 with infill line width set to 0.4; 0.6 and 0.8. Second picture is the 3 cubes printed, and infill line width measured is 0.4 on all of them. And last picture is of a print with all Line width set to 0.8 mm than the infill line width measures 0.7 mm.

 

So is the problem software related? Or are there settings to be tweaked to get Just the infill line width to be 0.8 mm and rest of the lines to be 0.4 mm?

 

And I also tried to set all line width to 0.8 and than change individually perimeter line width to 0.4 mm, it was looking as I wanted in the preview but the actual part again came out wrong.

 

 

Tl;dr I am trying to keep the shell of the part a constant line width and perimeter count, and just change the infill line width. It works in preview, but not in reality.

 

help, please

[GregValiant 1,035]

A lot goes on in that little rectangle below the nozzle.

Line Width means different things in different situations.  Most people think of Line Width as the width of an extrusion under the nozzle...a rectangle that is "Line Width Wide" X "Layer Height Tall".

Line Width is actually the index distance between two adjacent extrusions.  That results in a rectangle that is indeed Line Width wide by Layer Height tall.  When there is no adjacent extrusion (like with your infill), then the single extrusion is un-confined on either side.  The width of the extrusion is then a function of print speed, the calculated flow, plasticity of the material, print temperature, and (dependent on the flow rate) maybe some other things like turbulence in the nozzle and the cooling effect of the flowing plastic on the hot end.  This is in fact the problem I have with "Single Wall Calibration Cubes" but in your case they may actually be of some use.

• In the Material section you can try adjusting the "Infill Flow" upwards.  This is where a single wall calibration cube may help.
• You could also try adjusting the "Infill Speed" downwards.  Going slower may allow the plastic to spread further.
• There is a new setting in 5.0 in the Speed section called "Flow Equalization Ratio".  The default is 100%.  Try setting it to 0% and see how it goes.

Getting a single wall to be a specific width is usually a matter of flow (as in volume of filament/mm of extrusion/second).  The final shape of the unconfined "Rectangle" (and consequently the width of the extrusion) is not the same as an extrusion that is confined on one side.

 

My Ender 3 Pro prints large models pretty good up to about 12mm³/sec.  With a .4 nozzle at .4 line width and .2 layer height that occurs at 150mm/sec print speed.

If I was to double the line width then each extrusion would require double the plastic.  I would need to cut the print speed in half in order for the extruder to keep up.

I would never advise to run any Line Width beyond about 1.25 X the nozzle diameter.  The velocity of the plastic coming out of the nozzle goes a lot higher and it's tougher to control how that plastic is going to spread.  In essence - if you want to print at .8 line width then put in a bigger nozzle.

 

[CM7753 0]

Thanks for your response.

 

So that setting is a bit weird.

I set line width to 0.4

Infill line width to 0.8 

and infill line multiplier to 3

so I have 3 infill lines next to each other

 

Now the overall width of infill lines in printed part is around 2.2mm (should be 2.4mm) but that's a reasonable error.

Weird thing is that the middle line is still thinner at around 0.4 mm thickness but the lines on the side are closer to 0.8. 

So probably a tunable issue, but don't want to deep dive in to that at the moment.

 

Thank you!