Geeetech

Hi, I'm having some trouble calibrating my mk8 extruder using the guide here ... https://mattshub.com/2017/04/19/extruder-calibration/

I'm using PLA with a nozzle temp of 210 but the amount actually extruded seems to change slightly every time I ask the extruder to push through 100mm. I eventually settled on an E-value of 100.3 (originally it was 93) and ran 3 tests with this value but different flow rates with the following results...

G1 E100 F50 - pushed 89.1 mm
G1 E100 F100 - pushed 80.2 mm
G1 E100 F200 - pushed 56.9 mm

Because I've only varied the flow rate for all 3 tests I can only assume I've got some sort of nozzle blockage that's capping the nozzle flow rate.

I can't hear any obvious clicking from the extruder stepper so I don't think thats an issue.

If anyone else has had a similar issue I'd be most grateful for some ideas on what to do next

Ok, I think I might have answered my own question here.

I did some maths to convert the input rate to nozzle flow rate based on the standard 1.75mm and the Geeetech 0.3 nozzle. It turns out that an input flow of 100mm/min (i.e F100) is around 55mm/s at the nozzle, way over the 35 mm/s in the default slicer setting.

F100 would be fine for. 0.4 nozzle as it’s only approx 30mm/s. So I’m going to recalibrate again using F50 (50mm per minute) and then double check my slicer settings. Hopefully will get back to a decent print quality

I fixed my issues by completing the extruder speed calibration with the following command.
G1 E100 F28 (If my maths is correct F28 equates to about 50% of the recommended nozzle flow rate of 35mm/s).

Once I set my E-value based on the measurements from this calibration test I have much better results with my print quality. You can then follow the second part of Matt’s guide (see link above) to calibrate the Multiplier (extruded width) but you will need some accurate callipers for this. I picked up some on Amazon for around £13.