Depending on the slicing software you use, if you have a dual- or multi-extruder 3D printer, you may notice that your prints come out with a one-layer thick shell surrounding them. This shell is called an ooze shield and is enabled by default in several slicing software suites for multi-extruder printers because it’s beneficial at keeping the surface of your print clean.
An ooze shield is pretty self-explanatory; it does what the name suggests and protects your print from oozing issues. , Its main purpose is to preferentially catch any oozing from any nozzle before it hits and sticks to the outside of the actual print. By printing the ooze shield as the first part of every layer, the nozzle in question gets primed, ready for immediate use.
Why Is Oozing Such an Issue for Multi-Extruder Printers?
Oozing happens when a nozzle isn’t in use. This is why it’s so much more of an issue for dual- or multi-extruder printers than for single extruder printers. A single extruder is almost always in use, with rare retractions. In a multi-extruder printer, often only one can be used at a time, meaning at least one extruder is sat idle.
When the extruder is idling, the nozzle is still hot, and the filament is still kept there. With the already molten filament being heated further, it gets runnier until it oozes out of the nozzle.
To some degree, oozing can be countered with retraction. This is where the extruder pulls the filament back when it’s not being used. By keeping it further away from the nozzle, it’s harder for it to ooze. In reality, though, it’s almost impossible to get the perfect balance between no oozing and having the filament primed and ready to print. An ooze shield primes the nozzle at the start of each layer whilst also protecting your print from oozing.
The main downside of using an ooze shield is that it consumes extra filament. If you want the exterior of your print to be perfect, however, then this is likely your best choice. Once your print is complete, the ooze shield should easily detach from the print bed. The small contact area generally makes this easy; it then easily slides off the actual print underneath without touching it.
Ooze shields are a great tool for protecting your prints from oozing-related artifacts. Have you got any tips to share for ooze shield settings? Feel free to share them down below.