Solving Over-Extrusion Problems with ColorFabb XT
ColorFabb XT, made with Eastman Amphora AM1800 polymer, is a favorite for 3D printing enthusiasts looking for toughness and chemical resistance. However, many users transitioning from PLA find that ColorFabb XT suffers from significant over-extrusion. This manifests as blobs on the surface, "fuzzy" walls, or parts that simply won't fit together due to dimensional inaccuracies.
Why Does ColorFabb XT Over-Extrude?
The primary reason for over-extrusion with XT isn't necessarily that the printer is pushing more filament, but how the material behaves under heat. ColorFabb XT has a higher viscosity and different die-swell characteristics than PLA. If your slicer is tuned for PLA or PETG, the default flow settings will likely result in too much material being deposited.
Top Fixes for ColorFabb XT Flow Issues
1. Calibrate the Flow Rate (Extrusion Multiplier)
This is the most critical step. For most 3D printers, the default multiplier of 1.0 is too high for ColorFabb XT.
- The Fix: Reduce your Flow Rate (or Extrusion Multiplier) in your slicer to 0.92 - 0.96.
- Testing: Print a single-walled cube and measure the wall thickness with calipers to ensure it matches your extrusion width setting.
2. Lower the Printing Temperature
While XT requires heat to bond (usually 240°C - 260°C), printing at the high end of the spectrum increases internal pressure in the nozzle, leading to "ooze-induced" over-extrusion at the start and end of layers.
- The Fix: Try dropping your temperature in 5°C increments. If the surface looks shiny and the layers aren't separating, you can likely afford to print cooler to reduce material flow.
3. Manage Retraction and Travel Speed
XT is prone to "stringing blobs," which can be mistaken for over-extrusion. Because the material is sticky, it can get pulled out of the nozzle during travel moves.
- The Fix: Increase your Travel Speed to 150mm/s or higher. This snaps the filament string before it can deposit a blob on the outer wall.
The Cost of Quality: ColorFabb XT Setup
Printing high-performance co-polyesters like XT requires reliable hardware. Here are the estimated costs for components that help manage flow and extrusion quality.
| Component | Estimated Price (USD) | Benefit for XT |
|---|---|---|
| ColorFabb XT Filament (750g) | $35.00 - $45.00 | High-grade Amphora AM1800 material. |
| Hardened Steel Nozzle (0.4mm) | $15.00 - $25.00 | Resists wear from specialized co-polyesters. |
| Digital Micrometer/Calipers | $20.00 - $45.00 | Essential for measuring flow rate accuracy. |
| Direct Drive Extruder Upgrade | $60.00 - $100.00 | Better control over XT's high-viscosity flow. |
4. Check Your Filament Diameter
ColorFabb maintains tight tolerances, but if your filament is slightly over 1.75mm (e.g., 1.78mm), it will cause physical over-extrusion. Use your calipers to measure the filament at five different points and enter the average diameter into your slicer.
Conclusion
ColorFabb XT is a premium material that requires premium calibration. By reducing your flow rate to roughly 95% and ensuring your temperatures are balanced, you can eliminate the blobs and dimensional errors associated with over-extrusion. Once dialed in, XT offers a level of mechanical strength and clarity that standard filaments simply cannot match.
