TL;DR: I'm looking to change the steps per mm but I'm not sure what to set it to. Do I decide on a temperature and change the rate based on the percentage for that temp? Or is there a more general setting I can put it to? Or is there a different underlying problem here?
I'm running into an issue with my Ender 3 where when I print PLA at different temperatures I'm getting different extrusion rates. I've done the test where marking it at 120 mm and then extruding using PronterFace 100 mm and measuring the distance and this is my results. I did two tests of each to confirm results
185 °C 80 mm left = 60 % under extrusion
200 °C 31 mm Left = 11 % Under Extrusion
210 °C 32 mm Left = 12 % Under Extrusion
220 °C 28 mm Left = 8 % Under Extrusion
230 °C 25 mm Left = 5 % Under Extrusion
When I feed 100 mm through the Bowden tube without the filament going through the hot end I get exactly 20 mm left meaning:
0% under Extrusion
echo: Steps per unit: echo: M92 X80.00 Y80.00 Z400.00 E93.00
I have been having this problem since I started. I normally print at 210 °C at 50 mm/s with a flow rate of 103 % which seems to work well for most prints but on flat walls on prints it under extrudes in the same spot each time it comes around to that point.
Steps I have taken so far:
Different PLA filaments. All perform the same
Replaced the nozzle with a new one
Checked all fittings with the bowen tube system
Printed a spring spacer to make the spring tighter on the extruder gear
Changed the Vref from 0.75 to 1 for the extruder stepper
The reason I changed the Vref on the extruder stepper is because the system would click back when printing as if the pressure was too great in the tube. Changing this has helped some of the under extrusion a bit.
So. depending on the temperature, it's harder or easier to push the filament by hand through the hot end. Maybe I need a better hot end?
My test print to replicate the issue. The ripple bit is brittle and under extruded.
This was a Prototype piece for an up-sized print I was planning. After going around it under extrudes at the same point each time 210 °C
Most of the print is fine just some parts are different. This is an inner wall.