Reg extrusion width

[Karan Chaphekar]

Hi

First of all i am not new to 3d printing. but i have question reg extrusion width which may be very simple. 

So i just calibrated my estep. the nozzle is 0.3mm. i have inserted extrusion width as 0.3mm. and i printed 0.3 wall thickness 1 loop cube to get single wall to measure actual extrusion width. now the single wall width is coming 0.35mm. so should i change my estep to get that value to 0.3 or there is something other method.

thanks in advance

[Marc Repnow]

Good question!

In KISSlicer, the nominal extrusion width w is interpreted as if the cross section of the extrusion was rectangular. Let h be the layer height, then the area of the rectangular cross-section is A=w·h, and KISSlicer sets the current extrusion rate accordingly. In reality, however, the sides of the extrusion of a peripheral loop are not rectangular but round (like a smaller rectangle flanked by two half circles left and right), and since A and h are fixed, the true shape turns out to be a bit wider than the defined extrusion width w. How much wider depends on the layer height h. The width of the rounded shape is w+(1-pi/4)·h, so assuming w=0.3 and h=0.2 the thin wall should measure w'=0.343.
By the way, when calculating a correction factor for the extrusion gain, the measured width should be corrected for the pi-term. Say the extrusion gain e results in the measured extrusion with w' of the thin wall. Then the corrected gain e' is e'=e·w/(w'-(1-pi/4)·h).

Side note 1: The effective extrusion volume depends somewhat (very little though) on the back-pressure caused by the material flow in the hot end and the printed part itself. For example, when printing the outer loop (or a thin wall), the extruded material has more options to evade than, say, when printing the inner loop where the material has to push against the next outer loop. I still would not recommend to set the extrusion gain so that the thin wall object will be over-extruded, but it should also not turn out to be much under-extruded.

Side note 2: Other slicers might interpret extrusion width and extrusion correction settings differently. SFACT, for example, interprets extrusion width as the width of the thin wall (i.e., extrusion width is taken as the width of the rounded extrusion shape). Moreover, the correction factor for extrusion is the inverse of the extrusion gain.

[Davide Ardizzoia]

The most critical part is filament width (and height, if it is not perfectly round).
Therefore you should make sure that Kisslicer has been told the correct filament diameter.

Concerning E steps, you should perform feed calibration: using your preferred printer control software, you should verify that your printer is feeding EXACTLY 100mm of filament when told to do so. If you find any difference, then you should compendate your Esteps.

Third, be sure that you are not overheating your filament: too much heat means more fluid polymer behaviour resulting into a wider (a bit, ok) extrusion and less nozzle pressure.

Last, KS has a "bed roughness" parameter: abusing of this may cause a bit of overextrusion, too, at least on first layers.

Best Regards
Davide Ardizzoia

[Karan Chaphekar]

Thank you all 

so i should not check my thin wall? should i ignore it. i am sure that the extrusion width was always more even if i was at low or high temperature.

can my nozzle size be wrong? or is it die swell? 

also what is your method to find correct temperature?

i have aluhotend with replicator like carriage. my cooling for hotend and object are not fixed. i am fiddling with it.was using same fan for both now made cowl so it only give air to heatsink. tldr cooling is mess.

[Karan Chaphekar]

so after filament dia,e calibration,and temperature. what extrusion width to use? 0.3 for 0.3 nozzle?

i was using 0,4 by calibrating flow rate so my thin wall is 0.4. 

i did all of the above things but forgot to change 0.4 to 0.3, and funnily the object came 20.02 for 20mm. dont know why

so i think there should be 1 method to find extrusion width. many users use width other then nozzle, how did they find it.

i am not kind of guy who will do calibration by eye, i need a consistent technique.

On Wednesday, 14 May 2014 01:32:27 UTC+5:30, Karan Chaphekar wrote:

[Alan Timm]

Someone jump in and correct me if I'm wrong, but I thought the commonly given advice was to set your extrusion width to your nozzle width + 10%, then calibrate the extrusion multiplier to that width.

I'm running the E3D V5 hot end, which comes with a 0.40mm nozzle.

So I set Extrusion Width, and Infill Extrusion Width to 0.44mm