Multi-Color 3D Printing: AMS, MMU & Manual Swapping Guide

Single-color prints are great, but multi-color 3D printing is where things get really exciting — custom figurines, detailed prototypes, branded parts, functional multi-material components — all without hand-painting. Here's how to do it, from beginner to advanced.

Method 1: Automatic Multi-Color with AMS or MMU

The easiest (and most expensive) way to print multiple colors is with an automated filament switching system.

Bambu Lab AMS (Automatic Material System)

The AMS sits attached to your Bambu Lab P1S or X1C and holds up to 4 spools. You can daisy-chain two AMS units for 8-color printing.

• Pros: Plug-and-play, Bambu Studio handles all the switching, supports water-soluble PVA for soluble supports
• Cons: AMS costs ~$300–350, generates purging waste (the printer purges into a tower between color changes)
• Best for: Multi-color parts, gradient effects, soluble supports

The AMS handles filament loading, switching, and moisture sensing. We carry one at Forgely Roy — come in and watch it in action.

Prusa MMU3 (Multi Material Upgrade)

Prusa's MMU3 adds multi-material capability to the MK3.5 and MK4 using a filament buffer system and single extruder.

• Pros: Works with existing Prusa printers, 5-color capability, lower cost than dedicated multi-extruder systems
• Cons: Slower than AMS, requires more calibration, filament buffer takes up desk space
• Best for: Prusa users who want multi-color without buying a new printer

Method 2: Manual Filament Swapping (Free!)

You don't need expensive hardware to print multi-color. This technique works on any printer and any filament.

How It Works

Most slicers (PrusaSlicer, Bambu Studio, Cura with plugins) let you pause the print at a specific layer height or Z-level. The printer stops, you manually swap filament, then resume printing.

Step-by-Step

1. In your slicer, add a "Filament Change" or "Pause at Z" command at the layer where you want the color to switch (e.g., Z=10mm for a logo on top of a phone case)
2. Start the print normally with your base color
3. When the printer pauses, unload the current filament and load the new color
4. Resume printing — the printer will purge a bit of the new color, then continue
5. For more than 2 colors, repeat: add multiple pause commands in the slicer

Pro Tips for Manual Swapping

• Pre-load your next filament before the print starts so you're not scrambling when it pauses
• Don't let the nozzle cool — swap quickly to avoid clogs from cooling filament in the hotend
• Wipe the nozzle after swapping to avoid mixing colors at the seam
• Expect a small seam on the outside where colors change — this is normal and can be sanded out later
• Use "Filament Change" G-code (M600) rather than just pause — it retracts and parks the nozzle automatically

Method 3: Iris / Vase Mode Color Blending

If you want continuous rainbow/gradient effects without swapping at specific layers:

• Iris Folding (Bambu Studio): Gradually transitions between 4+ colors for a blended rainbow look
• Manual gradient: Run a "wipe tower" print style where the printer gradually transitions between colors over 20–30 layers
• Co-extrusion filament (like Rainbow PLA): A single spool of filament changes color every few meters — gives you rainbow prints with zero hardware changes

We stock Rainbow PLA at Forgely Roy in multiple colorways — it's the easiest way to get stunning multi-color prints on any machine, any budget.

Multi-Color Design Tips

• Keep color changes at flat surfaces — avoid changing colors on steep angles or curves
• Use the purge tower wisely — it wastes filament, so keep color changes minimal (2-3 colors max)
• Design your model for multi-color — separate bodies in your CAD/STL file by color zone for cleaner results
• PLA to PLA works best — different materials have different temperatures, which complicates multi-material printing

Utah's Dry Climate Advantage

Multi-color printing is more sensitive to filament moisture than single-color (because the printer pulls from multiple spools). Utah's dry climate gives us a natural advantage — our filament stays drier longer between spool swaps.

Try Multi-Color at Forgely Roy

We have an AMS set up and running in our Roy location. Come watch a multi-color print, see the result quality, and we'll help you decide which approach makes sense for your printing goals.

📍 5519 S 1900 W, Roy, UT 84067
📞 385-449-2694
⏰ Mon–Fri 11–6 • Sat 11–3