Undesired filament retraction at beginning of a print

[pgx3s]

Hi there

A lot of times I extrude some material for testing and adjusting in front of an actual print.

Since a while I have to shut the printer off again before I start the print. If not most of the time the extruder retracts a lot of filament after zeroing the z axis.

That happens with ocotprint and simplify3d.

Printer: Makerfarm Prusa i3v 12"
Controller: Rumba
Firmware: BeckDacks

Any ideas?

BR
Manuel

[printbus]

You're seeing this retraction when starting to print a gcode file, right?

Do you see the undesired retraction when you zero the x-axis from the LCD panel?

It's likely the printer is doing just what it is told to do by the commands in the gcode file. Take a look at what you have in Simplify3D for the Starting GCODE script. If you need help understanding the commands, copy and paste them here or post a copy of your complete gcode file, changing the extension to .txt so 3DPrintBoard accepts it.

[pgx3s]

Hi printbus.
I'll check that.
The funny thing is that it just doing that, when I extruded manually (in the software) before.
When I restart the printer and reconnect before a print, every thing is allright.

Usually it is retracting so much material that the filament ops out on the top ...

[printbus]

Usually it is retracting so much material that the filament ops out on the top ...

Yeah, that's a lot of retraction.

It could also be that there are issues with relative vs. absolute positioning as far as the extruder movements. Here's what I have in my Simplify3D v2.2.1 starting gcode script:

; Simplify3D will already have printer at temperature by this point
M107     ;start with print cooling fan off
G91        ; relative positioning
G1 Z10 F120 ; raise up before homing to clear clips and prepare for wiping away priming
G28 X0 Y0    ; home X and Y
G1 E8 F180 ; extrude 8mm at 3mm/sec to prime
G1 E-2.5 F900 ;retract 2.5mm at 15mm/sec
G92 E0     ; reset extruded length
G28 Z0   ; home Z
G90        ; absolute positioning
M82       ; extruder to absolute mode
M117 Printing...

[pgx3s]

Thx, I'll try to check that this weekend.

BR
Manuel

[pgx3s]

Thx mate.

Ur start code helped to solve the prob.

BR
Manuel