Unable to Calibrate Extruder MK3
I have been fighting with my MK3 for months now trying to get consistent prints. I have tried the linear advance calibration and that resulted in models full of holes. As I have not rechecked the extruder calibration I decided to start there with the latest attempt.
I am finding that when I tell Pronterface to extrude 100 mm at 60 mm/min I get an actual filament value of anywhere between 90 and 98 mm. It is never the same, though I have kept everything the same between subsequent tests. I am using PLA at 210 C.
I have checked the extruder gearing and that is nice and tight. I have disabled the filament sensor, which didn't make any difference. I am running Firmware 3.2.0-555
Any help is welcome and appreciated.
Re: Unable to Calibrate Extruder MK3
What is the problem with your prints? A bad first layer, or bad surface?
Can you show some examples.
If you get different results every time you feed 100 mm filaments, the problem is in Bondtech feed or the teflon tubes are clamped so that the filament is not fed properly.
Bear MK3 with Bondtech extruder
Re: Unable to Calibrate Extruder MK3
I have the problems outlined in this topic: https://shop.prusa3d.com/forum/hardware-firmware-and-software-help-f64/filament-jams-in-heatbreak--t15788.html
and have posted pictures in this topic: https://shop.prusa3d.com/forum/hardware-firmware-and-software-help-f64/how-to-use-and-tune-the-new-linearity-correction--t17470.html
The first layer looks fine until it suddenly stops extruding for some period of time, then it starts again and looks normal. The linearity test prints all look like the attached photo. I don't have pictures of the other issues.
I have not touched the PTFE tubes and I don't see any way for them to get clamped as there are no compression fittings to clamp them. Can you clarify what you mean?
I have checked the tightness of the drive gear on the extruder stepper. I can find no source of this issue to date.
Re: Unable to Calibrate Extruder MK3
That looks to me like it might be a partially clogged nozzle or heat break. You should do several cold pulls with a sticky filament- it may go away.
Re: Unable to Calibrate Extruder MK3
Wouldn't a partially clogged nozzle or heatbrake cause consistent underextrusion? If I understand clogs correctly they are always there and restrict flow.
What would cause a clog? How do you do a cold pull on this printer?
Re: Unable to Calibrate Extruder MK3
Solved! Apparently when I had to remove the extruder second gear to clear some deformed filament, debris got in the second gear door and jammed so it wouldn't swing, meaning the spring tension wasn't right. I pulled the door off to make sure the gear was turning freely and cleaned out the debris. Now to see what else that was causing. Thanks for the input.