Filament problem

[Izzy]

Is anybody else having the same problem?
After a print, the filament retracts 15mm, but then has problems starting the next print. I looks like as it retracts the material necks, but because the filament is still hot enough to deform it forms a small collar as it retracts into the Bowden tube, which then is too large to fit back through the I2K insulator into the hot end.
The problem could be resolved if the end of print retraction was only 10mm, but I do not have the knowhow to correct it.
Any help please?

[drayson]

Which slicer do you use?
Could it be that in the end/footer code of the slicer has a too high retract value entered in?

e.g. my cura end code:

;End GCode
M104 S0 ;extruder heater off
M140 S0 ;heated bed heater off (if you have it)
G91 ;relative positioning
G1 E-1 F300 ;retract the filament a bit before lifting the nozzle, to release some of the pressure
G1 Z+0.5 E-5 X-20 Y-20 F{travel_speed} ;move Z up a bit and retract filament even more
G28 X0 Y0 ;move X/Y to min endstops, so the head is out of the way
M84 ;steppers off
;{profile_string}

[Izzy]

Hi Drayson, I'm using Cura. The std setting that the code adds to the end

[drayson]

Hmmm... Strange... I always prime manually to be sure to get ink out of the pen...

[Dim3nsioneer]

@Izzy: One has to edit configuration.h of Marlin. Near line 600 in my configuration.h (I use Ultimaker2Marlin but have it customized so your exact line number might not be 594), I use:

Code: Select all

#define END_OF_PRINT_RETRACTION 12		// number of mm to retract when printer goes idle

instead of the standard 20 or so...
I have no problem with the I2K this way.

[Izzy]

Cheers D3, next question, using Windows 10 how do I edit the file?

[Dim3nsioneer]

Don't know... I'm still on Win8.1 ... I use xemacs or the Arduino IDE.

[Izzy]

my computer language skills are very lacking, in between OU courses I'm trying to learn the Raspberry Pi, but picking it up for a couple of months in the summer each year doesn't get me far, so editing the code I need to start from 101
Perhaps some kind person will start a thread to teach us