blode
Posts: 1
Joined: Thu Dec 26, 2019 11:29 pm

delta skirt starting position

Thu Dec 26, 2019 11:36 pm

Hi all,
I have a specific problem with my Delta printer when S3D starts a print. My printer homes to the top, and it has quite a travel down after preheating the hotend then bed. Because I use PETG, this typically means I need to watch and somewhere around 5 cm remaining, pluck the oozing filament from the hotend before it touches down in the center of my print before moving to the perimeter to start the skirt.

Is there a start script I could employ that directly moves the nozzle to the outside perimeter after the home+preheat phase? As it stands, if I forget to watch the hotend down, I will have a single errant strand of filament on the bottom of my print. I tried searching the forums because I cannot believe this would be such an uncommon issue with Deltas, but maybe others print offset from the center or use PLA.

Let me know if I have a certain misconception or am going about this wrong!

SteveYYC
Posts: 8
Joined: Sat Jun 16, 2018 5:01 pm

Re: delta skirt starting position

Wed Jan 01, 2020 8:02 pm

If you want your print-head to move to the edge of the bed before starting a print you'd need to add a G1 command to move to the edge.
This code is about the simplest you could use. I used this snippet at the start of my job files for a long time.

*** THIS CODE ASSUMES ABSOLUTE POSITION COORDINATES ***

Code: Select all

G1 X<bed radius> Z25 F<feedrate> 	; 	Move to the edge of the bed, 25 mm above the print surface
M226	; 	pause for you to clean the strings off the nozzle
You'd have to un-pause your printer after you cleaned off the nozzle.

If you wanted to (and if your machine's geometry & firmware allows), you could get a little fancier and move the nozzle off the edge of the bed and wipe the string off on the bed edge like this:

Code: Select all

G1 X<bed radius> Z10 F<feedrate> 	; 	Move to the edge of the bed, 10 mm above the print surface
M564 S0	; turn off axis limits 
			; *** IF YOU DO THIS AND ISSUE A LARGE MOVEMENT COMMAND YOU CAN DAMAGE YOUR PRINTER ***
			; *** IF YOU ARE USING RELATIVE COORDINATES THE FOLLOWING G1 COMMANDS WILL LIKELY DAMAGE YOUR PRINTER ***
G53		; FORCE movement to use absolute coordinates
G1 X<bed radius+a little> Z0 F<slow feedrate> ; Move the nozzle to zero height but just past the edge of the bed
G1 X<bed radius-a little> Z0 F<slow feedrate> ; wipe the string/ooze off on the edge of the bed
M564 S1	; turn axis limits back on
G1 Z10

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