How do you calibrate your extruder

Hello everyone,

This is just a general question. I'm not saying I have a problem, I'm only asking out of curiosity.

To calibrate my extruder, I will remove my Bowden tube from my hotend assembly, then send "G1 E100 F120". I will then use my calipers and measure what came out. I will do this 10 times, then average the results. I will take that value, then figure out the percentage of how off I am. Then I will change the steps to match. After the change I will double check to see if the change worked.

I will then print a 20mm cube, with one 0.5mm thick wall, no infill, no top or bottom. I then measure (3 places per side) the thickness of the wall. My measurements are always over the 0.5mm thickness I set. I've seen at times 0.6mm thick spots.

So my question is... What is you tried and true way to calibrate your extruder? Do you try to get 100mm out of your extruder? Or do you try to make the walls the correct thickness?

Thanks
TC

Start here: [reprap.org]

the wall thickness is the ultimate test of extrusion accuracy. But the amount of plastic extruded will vary with the filament diameter. So you have to either slice with the measured and calculated average diameter of the filament or use the nominal diameter and then tweak the flow/extrusion multiplier to get the right line width/wall thickness. You'll have to do one or the other for every spool of filament because they are all different sizes, unless the print isn't critical.

Edited 1 time(s). Last edit at 07/10/2018 11:55PM by the_digital_dentist.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

Back pressure from the print head reduces the extrusion rate a little. So it's more accurate to leave the hot end connected and measure how much filament goes into the extruder.

Even with the extruder correctly calibrated, I find it's often necessary to adjust the extrusion factor a little to get the best results from a particular roll of filament.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].