Can't Get Cura to Prime

[heathenx]

I've been playing with Cura 14.03 lately. I'm having trouble getting the extruder to prime or purge enough plastic before it it prints my actual part. It's having trouble getting started. Doesn't want to ooz enough plastic before the real print begins. I keep adding more and more skirt passes and I've gone out about 10mm around my part to help but there must be a setting in the start gcode to help with this? Any tips? S3D doesn't have this issue so it must be something I need in Cura. It's driving me nuts.

[Polygonhell]

There are two settings in cura that affect this.
If you are printing with a skirt you can specify a minimum amount of extrusion that must be present in the skirt, Cura will add loops to acomodate this for smaller parts.
There is also a set amount it extrudes before starting printing, I think by default this is 3mm. I don't have Cura on this machine, but I think both settings are in the expert menu Command-E on a Mac, probably Alt-E on windows, the 3mm extrusion might be in the start GCode.

It's often easier to just load the GCode into a host program, preheat and prime the extruder manually.

[heathenx]

I have been playing with those settings and it still won't prime before starting my print. It's as if my extruder is jammed. If I disable the stepper on the EZStruder material flows out like warm butter. No jam whatsoever. Oddest thing. I don't get it. What's the best way to manually prime it? I'm not connected via USB. I run everything from SD card.

Update: I've stripped out my custom start gcode in Cura. The only command that I have the Rostock doing is homing. I'm working around the issue by going with a 40mm offset from the part on my skirt. Seemed to have helped.

[Tinyhead]

Manually prime it by relieving pressure on the EZstruder via the red handle and manually push the filament down.

Do you eventually get filament coming out? Or have you simply not been able to extrude for a while? I know sometimes if I have a jam, if it sits there, it might ooze like everything is fine, but if I push on the filament, it's jammed solid and I get nothing coming out.

[heathenx]

@Tinyhead

Yes, it eventually extrudes, it just takes forever. I'm printing a small 1" x 1" part so perhaps it can't prime fast enough. What's odd is why it even take any amount to time to prime at all when the hot end is up to temperature. If I manually feed it filament just falls freely out of it just the way that it should.

Anyway, one nice thing about Cura as opposed to S3D are the holes. Cura prints those really nicely and much more accurately. Seems like my holes with S3D ALWAYS come out much smaller. I think Cura prints a little more accurately overall regarding dimensions. Is that just me or do you guys notice that too?

[heathenx]

I finally got this issue solved. I posted over on the Cura forums and Daid wrote that I needed a G92 E0 in my start gcode. That sets the extruder back to 0. I remarked all of the default Cura start code and I noticed that the G92 E0 is in there twice. So, I guess the trick was adding that line to my start code, which I did twice. My anchor line and my skirt get squirted now just like it should. Here's what I have now.

Start gcode:

Code: Select all

;Sliced at: {day} {date} {time}
;Basic settings: Layer height: {layer_height} Walls: {wall_thickness} Fill: {fill_density}
;Print time: {print_time}
;Filament used: {filament_amount}m {filament_weight}g
;Filament cost: {filament_cost}
;M190 S{print_bed_temperature} ;Uncomment to add your own bed temperature line
;M109 S{print_temperature} ;Uncomment to add your own temperature line
;G21        ;metric values
;G90        ;absolute positioning
;M82        ;set extruder to absolute mode
;M107       ;start with the fan off
;G28 X0 Y0  ;move X/Y to min endstops
;G28 Z0     ;move Z to min endstops
;G1 Z15.0 F{travel_speed} ;move the platform down 15mm
;G92 E0                  ;zero the extruded length
;G1 F200 E3              ;extrude 3mm of feed stock
;G92 E0                  ;zero the extruded length again
;G1 F{travel_speed}
;Put printing message on LCD screen
;M117 Printing...
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;####Rostock Max####
G28 ; home all axes
; ***start of purge line***
;M320 acceleration enabled for all commands that follow (DISABLED TEMPORARILY)
;M201 X850 Y850 Z200 E10000; limit acceleration (ENABLED TEMPORARILY)
G1 Z0.2 F6000.000; move to first layer height
G1 X90 Y-90 F10000.000; move to front of build plate
G92 E0; zero the extruded length (for Cura 14.03 only - skirt issue)
G1 X-90 Y-90 E24 F1000.000; extrude a purge line on the build plate
G4 P2000; wait for ooze to slow
G1 Z0.0 F6000.000; lower nozzle height to bed
G1 X-90; wipe nozzle
G92 E0; zero the extruded length (for Cura 14.03 only - skirt issue)
G1 Z0.2 F6000.000; move to first layer height
G1 F10000; ensure fast travel to first print move
; *** end of purge line***

End gcode:

Code: Select all

;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
;G90                         ;absolute positioning
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;####Rostock Max####
M104 S0 ; turn off temperature
M140 S0
G28 ; home X axis
M84 ; disable motors
M106 S0; turn off cooling fan if on (M106 S255 = 100% on)

Ref.
http://umforum.ultimaker.com/index.php? ... t-problem/" onclick="window.open(this.href);return false;