Extruder Steps per/mm changing with extruder temp

so im been trying to work out my steps for mm for the extruder, but im having issues of how much it extrudes each time

the lower the temp the less it extrudes and the higher the temp the more it extrudes, yes that sounds like the filament is having a hard time pushing through

im testing with PLA ive tried 190c 210c and 225c and each one gives a different result…

the feeding gear isnt slipping to my knowledge, i tried holding the filament and it keeps pulling with alot of force, and i dont think the steps are skipping

the feed speed 60mm/m

190c - extrudes 90mm
210c- extrudes 99mm (what im calabrating it at till i found this bug)
225c - extrudes 105mm

all the tests are out of 100mm extruding, so its not a small amount

i thought maybe it was feeding in to fast, so i extruded 10mm/min so super slow…

190c extruded 102mm
225c extruded 106mm

to me its looking like its struggling to feed, but at that slow rate, i dont understand

im using the e3d v6 with titan extruder, marlin software

how do i fix this? is it a setting in the Marlin software that is controlling it? i dont understand why the temp is having such a big effect on the results

Arent you meant to measure the filament taken in and without a hotend so it just comes out the extruder unheated...

Quote
Dust
Arent you meant to measure the filament taken in and without a hotend so it just comes out the extruder unheated...

i just followed this from Thomas Sanladerer - [www.youtube.com]

but i dont see why it should matter, if its connected or not, end of the day it needs to extrude through it, and 100mm is 100mm with or without the extruder, but something is messed up with mine because it should be the same always

Edited 1 time(s). Last edit at 07/01/2019 08:49AM by perplex.

so i swapped the motor and same issue, so its not skipping steps or under powered

only one i cant really test is if the filament slips, but i dont think it is since i cant even move it when i try pulling it.

so it must be a setting in marlin, i dont understand why it would push more filament through when its hotter

ideas?

When it's hotter the melted filament is more fluid so there is less back pressure and the incoming filament will encounter less resistance.

If you remeasure the e-steps without the filament going through the hotend and it's correct then perhaps you have a nozzle that needs attention due to a clog or some other restriction.

its a new setup so, nothing is clogged yet

yes i understand, when its hotter, its more fluid, but its a mechanical motor spinning the exact speed both times, so how could the results be different?

i did more tests

i took the extruder off set the temp to 190c and 225c and they were only .5mm off so ill call that margin of error, so that means its not the firmware, i then put the extruder back on with the new settings i just got from using no extruder and tested it again, 9mm under extrusion at temp 200c

so its not the firmware
not the motor

it has to be slipping on the filament… but i cant even pull it out myself…

unless there is something im not thinking of…