How does Line Width effect Flow?

[ssashton 2]

Hi,

 

I've searched but am not actually clear about this. 

 

Does the Line Width setting in Cura effect the absolute flow?

 

If I keep my nozzle setting at 0.4mm in printer settings but increase Line Width to 0.5mm, for example, I can clearly see line to line spacing getting wider in the preview. In this case will Cura automatically increase flow to actually achieve printed lines that are 0.5mm and merge together when printed? 

 

Or do I need to manually increase Flow percentage by a corresponding amount to achieve a printed line which is actually 0.5mm?

[nallath 1,124]

Cura will extrude in such a way that the 0.5mm is reached (or well, it will try to, it might actually fail if the difference between line width and nozzle size is too much)

[burtoogle 515]

I use 0.5mm wide lines all the time with an e3d v6 0.4mm nozzle and get very good results.

[ssashton 2]

Thanks for the clarification!

[yellowshark 153]

In addition you will be pushing more filament per sec out of the nozzle so possibly may need to increase extruder temp a bit (if all other settings remain the same). I.e. if you physically swapped your 0.4 nozzle to 0.8 you would definitely need to increase the temp. But I guess 0.4 to 0.5 you might get away with but it is a 25% increase in volume. Probably depends on whether your current settings are veering towards too hot or too cold.

Edited November 6, 2019 by yellowshark

[ssashton 2]

Thanks. I am only printing PLA 99% of the time which I find has a pretty wide temperature range to work with. Also I'm not actually changing the nozzle, just the line width to optimise the number of walls and avoid tiny infill moves.

 

Do you guys think increasing Line Width above the physical nozzle size is going to increase back pressure in the nozzle and lead to more stringing and blobing? I'm using a boden setup which doesn't help.

Edited November 6, 2019 by ssashton

[yellowshark 153]

Appreciate you are not changing your nozzle 😉Yes PLA does have a wide temp range, which is problematic because it makes you think your temp is OK when it is not. Well it may be OK but so is your print, instead of being great. This is especially important when it comes to dimensional accuracy and delicate features.

I do not know what it is but there has to be a point where difference in physical nozzle and line width will cause problems such as you say. I only ever print with line widths that match the width of extruded filament, which in my case is 0.45mm. The difference in print quality between 0.4 and 0.45 is noticeable, albeit not dramatic. I have not calibrated my 0,8mm nozzle yet, rarely use it.