1

Hi all,

This is for the coders (of which I am only pure noob). I am trying to get the machine to reverse the filament 10mm at the end of a print, and advance it 10mm at the beginning of a print as I am all too often getting expansion when cooling down and then nothing in the hot end to start the next print with. However, I can’t get the code to do this. The following is my start code:

[G28 ;Home

G1 Z15.0 ;Move the platform down 15mm

G1 F200 E10 ;Set fan speed to 200mhz, advance filament 10mm]

Can anyone see why this isn’t giving me the results I’m expecting?

Cheers

2

Hi there,

Maddie here from 3D Hubs. I’d recommend zeroing out your E location before and after, so your code would become this.

G28; Home

G1 Z15; move platform down 15mm

G92 E0; zero extruder length

G1 E10 F200; purge 10mm

G92 E0; zero extruder length

I hope this helps!

Best,

Maddie - 3D Hubs

3

Thanks, the zero code has helped me out! Does this mean that each reference to the extruder isn’t ‘advance by x amount’ but ‘advance to next length’ which is a sum of all previous advances?

Cheers,

OLC

4

Awesome! I’m glad I could help.

It depends what “mode” your printer is in, there are two.

Basically G91 puts the machine into relative mode, so saying E10 will advance the extruder by 10mm no matter where it was before. G90 is absolute mode, so it will place it at the E10 position no matter where it was before. If it was at E0, it’ll advance 10mm, while if it was at E100, it’ll retract by 90mm. Since I wasn’t sure which mode your gcode was in and didn’t want to risk messing up what it needed to do, zeroing the distance before each print is the safest.

I hope this makes sense!

Best,

Maddie - 3D Hubs