Machine Shop

Thing-O-Matic: Revised Wipe and Splodge

Notched wiper
Notched wiper

So I finally got around to properly trimming & installing the silicone wiper to suit the aluminum build plates, then measuring where it sits in XYZ coordinates.

The notched upper edge (that’s not a shadow) more-or-less matches the nozzle shape, but I doubt that’s critical. The key part: make it short enough to miss the bottom of the insulation blanket around the Thermal Core, which is much thicker on my Extruder than yours.

From this angle you can see the nozzle just in front of the wiper. I used a low-profile bolt, although it’s still slightly higher than the top aluminum build plate.

Nozzle in wipe position
Nozzle in wipe position

This G-Code routine helped figure out all the parameters. Define the maximum Z height properly, then fiddle with everything else to center the nozzle on the platform, pause in front of the wiper, and stop at the splodge position.

(---- manual wipe and splodge alignment ----)
(MakerBot Thing-O-Matic with aluminum HBP)
(Tweaked for TOM 286)
(Ed Nisley - KE4ZNU - April 2011)
(-- set initial conditions)
G21		(set units to mm)
G90		(set positioning to absolute)
(-- home axes)
G162 Z F1500	(home Z to get nozzle out of danger zone)
G161 Y F4000	(retract Y to get X out of front opening)
G161 X F4000	(now safe to home X)
G92 X-53.0 Y-59.0	(set XY coordinate zeros)
G92 Z116.0    (set Z for HBP with aluminum sheet platform)
G0 X0 Y0 Z10	(pause at center to build confidence)
G4 P2000
(-- manual nozzle wipe)
G0 X56 Y-57.0 Z15	(move to front of cut-down wiper)
G0 Z5   		(down to wipe level)
G4 P4000		(Wait for filament to stop oozing)
G1 Y-40	F1000		(slowly wipe nozzle)
(-- manual splodge)
G0 X-52 Y-58  (to front left corner)
G1 Z0.50      (just over surface)

This becomes a chunk of the heavily tweaked start.gcode that Skeinforge folds into every sliced file.

Of course, just when I get this figured out, Skeinforge 40 eliminates the Outline plug-in, shuts off the extruder before zipping off to begin the Skirt (starting from the right side!), and prints the perimeter thread of the bottom layer first. More pondering is definitely in order…