Disable filament prime blob

[sealfab]

Prime blob is probably not the best term but idk what its called. Im referring to blob that gets extruded on the front right corner of the bed. As far as I can tell my slicer is not generating this so is it in the FF firmware and can it be disabled? Seems like every couple of prints it doesnt stick and if I dont catch it just stays stuck to my nozzle and running the print.

[wirlybird]

It is in the start script in the slicer.

[sealfab]

thanks, which line is it?

; **** Replicator 1 dual start.gcode ****

M73 P0 ; enable build progress

G162 X Y F3000 ; home XY maximum

G161 Z F1200 ; home Z minimum

G92 Z-5 ; set Z to -5

G1 Z0 ; move Z to 0

G161 Z F100 ; home Z slowly

M132 X Y Z A B ; recall home offsets

M135 T0 ; load right extruder offsets

G1 X150 Y-70 Z30 F9000 ; move to wait position right hand side of the table

G130 X20 Y20 Z20 A20 B20 ; lower stepper Vrefs while heating

M126 S[fan_speed_pwm]

M140 S[bed0_temperature] T0

M134 T0 ; stabilize bed temperature

M104 S[extruder1_temperature] T1

M133 T1 ; stabilize left extruder temperature

G130 X127 Y127 Z40 A127 B127 ; default stepper Vrefs

G92 A0 B0 ; zero extruders

G1 Z0.4 ; position nozzle

M135 T1 ; left tool

G1 X110 Y-70 E30 F300 ; move nozzle

G1 X120 Y-70 Z0.15 F1200 ; slow wipe

G1 X110 Y-70 Z0.5 F1200 ; lift

G92 A0 B0 ; zero extruders

M73 P1 ;@body (notify GPX body has started)

; **** end of start.gcode ****

[dewhisna]

The specific line doing the extruding of the filament, based on your posted script, is the “G1 X110 Y-70 E30 F300” as that tells it to extrude “30” on the extruder after zeroing out the extruder position a few lines above. It’s also using that to move the nozzle to that position on the build plate. I split mine up into a couple of lines.

Instead of removing it, you may wish to just make it better. I had similar issues to what you are describing and I tweaked mine a bit. For starters, the “G1 Z0.4” line in your code tells it to position it 0.4mm above the build plate. That’s pretty high for making the anchor and is likely the number one reason yours isn’t sticking (assuming you remembered to put gluestick or whatever attachment medium you use down in that corner).

The last part of the gcode I use with Cura for slicing for my FFCP looks like this:

G0 X-110.5 Y-74 (Position Nozzle)
G0 Z0 (Position Height)
G1 E4 F50.0 (Create Anchor)
G1 Z15
G92 E0

Yes, I run the extruder all the way down to the Z-axis home (G0 Z0), but I also only extrude 4 instead of the 30 in the “G1 E4 F50.0” line. The “F50.0” makes that run very slowly to give it time to mash itself onto the plate and adhere (as it will squeeze out around the nozzle which is almost touching the plate). Then, I move the Z-axis up with the “G1 Z15”, which will still be at the slow F50.0 feed rate specified on the line above (since I didn’t override that), giving it time to pull out any extra “dribble” material in the nozzle. Then, I reset the extruder numbers with the “G92 E0” so the print will work correctly.

Only other thing different in mine is that I’m doing this on the left-side instead of the right, as you’ll see the “X-110.5” on the first line, where yours is a positive. Negative is left, positive is right side. It also looks like your code is using “G92 A0 B0” for its zeroing of the extruders instead of my “G92 E0”. But I think the net result is the same there.

Since I’ve been using this, it almost never fails to stick and prime correctly. I can literally hit print and walk away. Only occasionally will I have issues with certain filaments that tend to ooze more or less at start-up. You can try something similar or you can remove that part. Though I think you’ll find if you remove it, you won’t like the inconsistency of the start point since your nozzle won’t be primed the same each time.

[cobnut]

To be honest, I’d rather work out why it’s not sticking to the bed - this “purge” routine is a useful start to any print to clear baked filament from the nozzle and ensure it’s flowing freely. On my Prusa, I stuck a small strip of blue tape in the purge area (just 10mm wide), ironically because some filaments were too sticky at this point. Maybe you could try something similar - the tape will last for lots of prints.

[sealfab]

Is there anything that purging is going to do that skirt will not? I use painters tape and that works fine for itleast 5 prints but for whatever reason the purge does not consistently stick.