How to Prevent Oozing from the Inactive Extruder in IDEX Printers
In 3D printers with dual independent extrusion (IDEX) systems, a common challenge is managing the head that is not printing. While one is working, the other remains hot, which can cause the molten material to leak and ruin the work. 😐
The origin of the problem: unwanted oozing
This phenomenon, called oozing, occurs because gravity acts on the liquefied plastic in the inactive nozzle. The falling material creates imperfections on the surface and can even affect the internal structure of the part, a critical inconvenience when using two colors or materials with different properties. This oozing interferes with the precise movement of the head.
Key strategies to mitigate oozing:- Retract the filament (Retract): This function, common in slicing software, pulls the filament away from the hotend to relieve internal pressure in the unused nozzle.
- Program a wipe (Wipe): Before starting to print, the active head moves to rub its nozzle against the edge of the bed or a designated area, removing residues.
- Adjust the standby temperature: Some users set a slightly lower temperature for the inactive extruder, reducing the fluidity of the material without cooling it completely.
The irony is in designing a perfect part and then spending time and filament on structures that you're just going to throw away.
Advanced solution: auxiliary purge elements
When retracting and wiping are not enough, more robust methods are needed. These structures capture the residual material before it contaminates the main part.
Types of purge structures:- Cleaning tower: It is a column printed next to the main model. The inactive head deposits excess material there each time it reactivates, acting as a waste area.
- Ooze Shield: It consists of a thin single-layer wall that surrounds the part. The non-working extruder discharges into this barrier, thus protecting the visible and critical surfaces of the print.
- Purge on the bed edge: A simple technique where the inactive head expels a small amount