Slicing with Dual Extruders: Ooze Shields and Prime Towers
Dual-extrusion 3D printing allows you to print with two different colors or materials (like PLA and soluble PVA supports) in a single print. However, dual extrusion has a common issue: the idle nozzle will drool molten plastic as it sits heated, leaving ugly color bleeds and blobs on your model. Slicing dual-extrusion models requires configuring prime towers, ooze shields, and nozzle standby temperatures to keep prints clean.
Prime Towers and Ooze Shields Explained
Slicers use these two structures to clean the nozzles during filament swaps:
- Prime Tower (Purge Block): A hollow square column printed on the corner of the bed. Before switching to print the model, the active nozzle moves to the prime tower and extrudes a small amount of plastic to prime the hotend flow and clear any old color.
- Ooze Shield: A single-layer-thick wall printed around the model. It acts as a barrier, catching any dripping strings from the idle nozzle before they can touch the model surface. You peel the ooze shield off after printing.
Nozzle Standby Temperatures
To prevent plastic from carbonizing and oozing, configure your slicer to drop the idle nozzle's temperature by 20°C–30°C when not in use. Slicers will heat the nozzle back up just before its print turn, keeping the plastic viscous only when active, although this increases print time.
Dual Extrusion for DesignForge Templates
Use dual-extrusion profiles to optimize our custom templates:
- Nursery & Kids Desk Nameplates: Slicing a dual-color nameplate on a dual-extruder printer is highly efficient. Use a **Prime Tower** to clear colors. Since nameplates are flat, color changes only occur on the top text layers, meaning the prime tower will be short and use very little filament.
- Custom Keychains & Pet Tags: Keychains feature small text. Set your ooze shield to "Disabled" since the prime tower is sufficient to clean the nozzle. Enabling an ooze shield on small keychains is a waste of filament.
- Cake Toppers: Use a dual-extruder setup to print the topper stick in a food-safe plastic and the text in a silk metallic filament, using a prime tower to prevent bleeding.
Recommended Print Settings for DesignForge Templates
To ensure high success rates and perfect visual finishes, use the following tested print profiles for our 3D nameplate, keychain, pet tag, and cake topper templates. Adjust your temperatures based on your specific filament manufacturer recommendations.
| Design Type | Filament Type | Layer Height | Infill Profile | Wall Count | Nozzle/Bed Temp | Slicer Optimization & Finish |
|---|---|---|---|---|---|---|
| Nursery Desk Nameplate | PLA | 0.20mm base / 0.12mm text | 15% Gyroid | 3 Walls | 200°C / 60°C | Enable variable layer height on letters; 100% cooling. |
| Teacher Desk Nameplate | PLA or PETG | 0.20mm | 15% Gyroid | 3 Walls | 200°C (PLA) / 240°C (PETG) | Enable Ironing on topmost surfaces only (30mm/s, 10% flow). |
| Kids Desk Nameplate | PLA | 0.20mm | 20% Gyroid | 3 Walls | 200°C / 60°C | Use multi-color pauses at layer transitions for colored letters. |
| Custom Keychain | PETG or TPU | 0.16mm | 30% Gyroid | 3 Walls | 240°C (PETG) / 225°C (TPU) | Slow down outer walls to 40mm/s for small keyring loop strength. |
| Custom Pet Tag | PETG | 0.16mm | 40% Grid | 4 Walls | 240°C / 75°C | Disable Z-hop to reduce fine hair stringing inside small letters. |
| Cake Topper | Food-Grade PLA | 0.20mm | 25% Concentric | 4 Walls | 200°C / 60°C | Coat prong with food-safe epoxy sealant. Avoid supports. |
Expert 3D Printer's Checklist
Before launching any complex print, run through this quick checklist to ensure maximum success and reduce print failures:
- Bed Leveling: Confirm your bed is trammed and that your Z-offset is dialed in with no visible gaps. Run an auto-level mesh before printing large flat objects.
- Filament Drying: Ensure your spool has been kept dry and stored in a sealed container with active silica desiccant. If printing PETG or TPU, pre-dry the filament.
- Build Plate Adhesion: Wipe down the PEI bed surface with 99% Isopropyl Alcohol (IPA) to dissolve finger oils. Do not use acetone on PEI plates.
- First Layer Inspection: Watch the first layer print completely to verify that the bead line is squishing down nicely and anchoring to the plate.
- Slicer Profile: Check that you have configured the appropriate infill pattern (like Gyroid) and turned off supports for flat items.
- Temperature Calibration: Set your hotend and bed temperatures exactly as recommended for your specific filament brand and polymer type.
- Cooling Fan Speed: Keep the part-cooling fan turned off on the first layer to prevent warping, and set it to 100% on subsequent layers for PLA.