Reduce Purge Waste

Reducing purge waste on an AMS or similar multi-material system can make a significant difference in both material savings and print efficiency. Multi-material FDM printers use purge cycles to clear previous filament from the hotend during color or material swaps, but there are practical strategies to minimize this waste.

Multi-Hotend Printers: The Best Solution

The most effective way to reduce purge waste is to use a printer equipped with more than one hotend and nozzle. IDEX (Independent Dual Extruder) and tool changer systems keep each filament assigned to its own hotend, minimizing the need for purging during swaps. Dual-head and similar machines provide much lower waste than single-nozzle systems that rely on AMS, MMU, ERCF, or Palette units.

Calibrating Flushing Volumes in the Slicer

Fine-tuning flush and purge volumes for each transition is crucial. Swapping from black to white typically needs 250–300mm of flushing, but changing from white to black generally only requires 60–80mm. Starting with a multiplier value such as 0.6 and adjusting based on material and color tests can help. Slicers often allow detailed adjustment or provide recommended settings based on transition colors.

Batch Printing: Multiple Parts on the Same Plate

Printing more than one object on the same build plate uses no extra purge material for each additional part, because swaps occur simultaneously for all objects. Running consecutive single-object jobs wastes more material compared to batch printing, so grouping prints together is a simple method to minimize waste.

Flushing into Infill

One effective way to reduce visible purge waste is to flush transition material directly into the infill of the printed model. This repurposes what would have been purge waste into a functional part of the object, provided outer walls are opaque or shell count is increased so infill colors do not bleed through. Increasing infill percentage can further absorb purge material without printing additional waste.

Flushing into an Object

Transition material can be directed into an extra printed object, such as a trinket or fidget toy, so the purge becomes a usable item instead of refuse. Any color shifts will be random, but this approach adds value and eliminates some waste.

Prime Tower Optimization

Prime towers help protect against color bleed, but once flush volumes are well calibrated, the prime tower size can be decreased. In many slicers, it is possible to shrink or even disable the tower, further reducing filament use without risking print quality.