wipebar for first extrusion


Hello Tom, i don’t know if this is idea is crazy enough or that there is a better solution but here it is:

I build an aluminium i3 clone and to get better print results i did some upgrades (like most people do :smiley: ) to make live a little easier.

Many times after i just started a print i’m called away and having a piece of filament messing up the first layers resulting in loss of time and filament…
My solution was to make a little wipebar from a metal paperclip to sheer off the first extruded filament after heating up the nozzle.
Just bend it to size, put a bit of tape on it and drilled 2 tiny holes in the aluminium heated bed.(making sure the nozzle isn’t colliding with it when bedleveling or homing)

Then I figured out the x, y and z position to get a nice brushing contact and added this in the start gcode. After G29 i added:
M117 Move naar wipe ;text
G1 F2000 X23 Y0 Z4.5 ;move
G1 F2000 X13 ;move

This way the nozzle is positioned nicly outside my bed so the filament can freely flow…
After extrusion of the filament i retract it 2mm and wait for 5 seconds to stop oozing and then do a wipe:

M117 Extrude 25 mm plastic ;text
G92 E0 ;zero the extruded length
G1 F200 E25 ;extrude 25mm of feed stock
G92 E0 ;zero the extruded length again
G1 E-2 F{travel_speed} ;retract 2mm
M117 Wipe nozzle ;text
G1 F3000 Y5 ;move to wipe nozzle
; M300 S300 P500 ;beep(not in use because it’s too loud when printing late :sunglasses: )

The bar just before wiping:



Yea, I longer wanted such a thing. My idea was wire brush just before the intro line starts. I think there are some other solutions out there and I think maybe some in commercial printers. But for me I never realized the project and still forget to clean my nozzle, especially PETG makes often a mess when the nozzle is not cleaned properly.




Here is the one I really interest in



hi, this is only an option when the bed is being moved in z direction… and mine doesnt. :sunglasses: (nozzle goes up, not the bed down…)
also my solution is not realy wiping in the sense of keeping the nozzle clean during printing, its just sheering off the initial filament. if a single extruder needs to be cleaned while printing you have other issues…
the video has nice wipe action, maybe i’ll try making 2 wipe passes for that extra protection (and it looks cool)
the solution in the video looks exelent for dual extrusion, it certanly uses less time and filament than the printed wipetowers in cura…



Maybe the thing to take from that design is the flexible wiper and dual swipe. That looks to be cut from a silicon windshield wiper blade, I imagine a standard rubber wiper might melt while making contact with the nozzle.

I also had a lot of issues with skirts getting dragged by having a corner sticking up and getting caught by a fan or sensor, so I started just doing a big line outside the print area where it won’t be disturbed using this pre-print gcode:

M115 U3.0.10 ; tell printer latest fw version M140 S[first_layer_bed_temperature] ; set bed temp M190 S[first_layer_bed_temperature] ; wait for bed temp M104 S[first_layer_temperature] ; set extruder temp G28 ; home all axes G29 ; auto bed leveling G1 X50 F5000.0 G1 Y-3.0 F5000.0 ; move out of print volume M109 S[first_layer_temperature] ; wait for extruder temp G92 E0 G1 X60.0 Z 0.2 E9 F500.0 ; start purge G1 X100 E12.5 F500.0 ; finish purge line G92 E0 M83 ; extruder relative mode
Code adapted from this video: https://www.youtube.com/watch?v=6csbJ5965Bk

It is a really fat purge line though, which I do like, but you can’t really print near it or it will definitely drag. I usually pick it up with tweezers after laying it down if printing something close to the front of the bed.