why extrude on a tower instead of a purging at full nozzle diameter and a small "T" shaped wipewall
I'm just getting into MMUs and it boggles my mind as to why all the purging is done at extrusion width and layer height with all the time space that takes.
Why not make a small "T" shaped wipewall where the hotend moves past it, extrudes in air at full nozzle diameter then finish by putting one layer on the small wipe wall before heading back to the parts being made? It won't save any material but it'll save space and time by extruding the purge material at the nozzle diameter instead of layer height and nozzle diameter width.
Sure it'll be a little messy with a bunch of curly plastic bits on the other side of the wipe wall but that could more readily be recycled than a large block of plastic and cleaned up pretty easily.
RE: why extrude on a tower instead of a purging at full nozzle diameter and a small "T" shaped wipewall
I got to wondering how I would go about experimenting with this type of wipe tower and looked at some gcode then looked at Prusa Slicer 2.6.0 and found:
Printer Settings -> Custom G-code -> Color Change G-code
M600
G1 E0.4 F1500 ; prime after color change
Would it be conceivable to disable wipe_tower and add some G-code in this section to move to position XY(other side of a "T" wipe tower), run extruder for Xmm to purge color then print one layer on top of the "T" pattern wipe tower and resume printing?
Also, will I need to do anything with built-in variables or should I figure this print head will be at the current new layer for the next color?