Material waste - mmu2

A project log for protoDEV 3d printer

diy direct-drive extruder 3D printer running Klipper firmware

Michal WojciechowskiMichal Wojciechowski 04/30/2019 at 09:280 Comments

With wipe/purge towers single nozzle multi-material system is wasting a lot of filament to maintain the change of color (switching the material type) feature even if you want to make the change once per printing. For example if You want to print something simple dual-color:

For me this is unacceptable waste of filament to get an fancy feature. 

So i tried to overcome this problem with an hobby servo wiper arm that could move the purged filament to a waste bin. 4 prototypes made and all with same major problem... At some point of moving the wasted filament from nozzle to waste bin it occasionally liked to jam in the wiper arm.

From the begining i wanted to use some kind of trap door mechanism. The fifth prototype was operational so i could test how much material needs to be wasted for single change of filament.

I'm using e3d volcano nozzle so it's quite long so i'm purging 70mm of extruded filament for each color or material change.

With this purge method i can now print simple dual color stuff without wasting much of material

But if i need to print something more complex (with a lot color/meterial) changes the wasted material weight should be comparable to wipe tower method. 

Another problem that may occur is that when the waste bin gets full i would make the print fail.

Need to make more tests to take a deeper look to find a solution for this.