E Steps vs Print E steps

Hey Guys,

So I am going to try and explain this as best I can.

So following Tiffid's calibration for my E steps per mm. By calculation I get around 450 steps per mm for my extruder.
After measuring 100mm and recalculating the e steps based on the length of material extruded I get 503 steps per mm.
However, my prints are clearly showing signs of over extrusion with this value.
Through printing and decreasing the e steps as shown in his calibration I start getting good prints at 440 steps per mm.

So I am so confused as if 100mm is being extruded when I specify 100mm but then when I print the wall thickness of 0.4mm ends up being 0.48. My nozzle is definitely 0.4 as I have measured it.

Could anyone help me understand.

Thanks

What host software are you connecting with?
Slicing program?
Slicing settings?
Filament size you are using vs. filament setting in slicing software?

It can look like you are over extruding if your axes are not calibrated. Have you calibrated X,Y,Z?

It is all about "volume". It is a calculation of 100mm of filament going into your hot end and controlled by your slicing settings into how many steps need to be made.

Edited 1 time(s). Last edit at 04/09/2015 06:39PM by KingRahl.

Extrusion depends on e-steps per mm and filament diameter. Have you measured your filament diameter? Regardless, e-steps per mm and filament diameter will give you a reasonable approximation of correct extrusion, which you then fine-tune during calibration using the extrusion multiplier (on Slic3r).

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First off, did you measure the filament going into the hotend and not what was coming out right? you get me confused with the way you write it. The measurement is going in, not out.

Now the over extrusion not necessarily is the steps fault, your extrusion multiplier might be to big. Don't know what kind of extruder and hotend you have, but a 0.9 to 1.0 multiplier is good.

Your nozzle is 0.4 and the width of the filament (extruded) needs to be wider than nozzle size for good adhesion purposes, usually for 0.4 is 0.46 so 0.48 its a hair thicker but not too bad. Check your extrusion width in the slicer, your filament should be the width specify in it +/- some error.

Man you guys are quick!!!

Thanks heaps for the support.

Okay initially I was using Cura but I have recently changed back to slic3r

My extrusion multiplier is set to 1 now that I have put my e steps back to 440 instead of 503.

I measure the 100mm of filament going in yes.

And my filament varies between 1.73 and 1.76 which I thought was good enough to put 1.75 into my slic3r settings.

Using repetitive host to slowly extrude 100mm

My prints are coming out good with a e steps of 440 but I just don't understand why if it takes 503 steps to extrude 100mm in repetier host why I have to drop my e steps down.

I use a brand new E3D v6 head and FSR bed levelling sensors. I have been having prints fail up to 6 hours in as the head grinds along the print due to over extrusion as I have measured my x y and z steps perfectly (delta Kossel)

Anyways guys any insight would be helpful and thanks so much for your help

Which is your extruder feedrate? it might be too fast, have you tried reduce it some and put you 503?

Are you measuring 100mm with the hot end removed? This would account for less resistance.
If you are printing too fast that your hot end can't melt the plastic quick enough can cause resistance.

Any resistance on the filament can cause the extruder to either skip steps or if your power is high enough, cause the hobbed end to cut into the filament. Also make sure the hobbed gear is tight enough against the filament not to slip but not so tight it squeezes it flat.

So... 1. slow the print speed 2. increase temp 3. check tension.

What is your nozzle diameter, how do you know, and what is the nozzle diameter set in your slicer?

Nozzle diameter is 0.4. It's a brand new e3d 0.4mm nozzle so that's how I know. And I'm going to try and recalculate it again tonight as my calculation may have been off