PrusaSlicer QR code generator — color-ready 3MF
Design a scannable QR code and download a 3MF with color assignments already inside. Import into PrusaSlicer, pick your printer profile, slice, print — MMU3 handles multi-color hands-off, single-extruder machines pause for the swap at a known Z height.
What you need
- A Prusa 3D printer — MK4, MK4S, MK3S+, XL, or Mini+. Any model that accepts a 3MF works.
- MMU3 (optional) — for hands-off filament changes. On single-extruder printers, PrusaSlicer inserts a pause at the color-change Z height and the printer prompts you to swap the spool.
- PrusaSlicer 2.7 or newer — earlier versions handle 3MF but their color-assignment import is less reliable.
- Two spools of filament in contrasting colors. Matte PLA is the safest choice; Prusament PLA and PLA-CF also print well.
- A link, Wi-Fi credentials or plain text you want to encode.
Step 1 — Design your QR code
Open qr3dmaker.com and paste your link into the input field. Pick two colors with real contrast (a light base with a dark code is safest), then choose an object shape — desk stand, keychain, or wall plaque. The live preview shows exactly what your printed object will look like.
Step 2 — Download the 3MF
Click Download 3D file. You get a single .3mf that contains two solid meshes (the base and the raised code), the color assignments you picked, and the correct object metadata for PrusaSlicer to group them as one printable assembly.
Step 3 — Open the 3MF in PrusaSlicer
Drag the file into PrusaSlicer, or use File → Import → Import STL/OBJ/AMF/3MF…. When PrusaSlicer asks whether to keep the color assignments, choose Yes — otherwise you will have to reassign filaments manually. The two meshes will appear grouped as one object with two extruder colors.
Step 4 — Confirm printer + filament profile
On the right sidebar of PrusaSlicer:
- Printer — pick the exact profile for your machine: Original Prusa MK4, MK4S, MK3S+ (with MMU3), XL 1-tool / 2-tool / 5-tool, or Mini+. Wrong printer profile causes offset issues on the color-change layer.
- Filaments — Filament 1 should be your base color, Filament 2 the code. If PrusaSlicer flipped them on import, click the color swatch next to each filament to swap.
- Print settings — the defaults for your printer are fine. No custom process needed.
Step 5 — Slice and export G-code
Click Slice now, review the preview to confirm both colors appear where they should (base plate first, then raised code on top), and export the G-code. Send it to the printer via Prusa Connect, direct USB, or SD card. On MMU3 the filament changes happen automatically; on single-extruder printers the printer will pause and prompt you for the color swap at the exact Z height where the code layer starts.
Step 6 — Verify it scans
Once the print is done, scan the QR with two or three different phones from about 20–30 cm before installing it in its final spot. If the PrusaSlicer preview showed both colors clearly and each module measures 1.5 mm or more, the printed object will scan.
Troubleshooting
Filament 1 and Filament 2 got swapped on import
PrusaSlicer occasionally reads the color order backwards from the 3MF, especially in older versions. Fix: click the small color swatch next to each filament in the sidebar, or drag them in the right order. Nothing to re-slice — save the corrected order and slice again.
MMU3 gives "filament runout" mid-print
The color-change zone in our QR object is a single, thin layer, and MMU3 rewinds far enough for the swap. If runout triggers, check that both spools have at least 50 g remaining and that the selector clicks fully into position — sometimes the buffer needs a manual reload. Consider raising the Cooling tube length in the MMU3 settings if the tip forming is inconsistent.
Color bleed on the raised code edges
PrusaSlicer purges into a wipe tower during MMU3 changes. If you still see a hint of the other color, increase Extra loading distance for the second filament, or add a wider wipe tower. The 3MF from QR3D Maker only has one color transition, so purging cost is minimal.
Single-extruder Prusa (MK4 / MK4S / MK3S+ without MMU3)
PrusaSlicer already supports color changes with an M600 at a chosen Z height. Open Preview after slicing, right-click on the layer where the code starts (about 2 mm above the plate by default for our models) and choose Add color change. The printer will pause at that exact height and prompt you to swap the spool.
Prusa XL — 2-tool or 5-tool head
On the XL, both filaments load into different tools. Assign each tool head to the right color in the printer profile and PrusaSlicer will handle the tool change automatically at the layer transition, without needing an MMU3 or a manual pause.
Related
PrusaSlicer QR code — FAQ
Do I need the MMU3 to print a two-color QR?
No. On any single-extruder Prusa (MK4, MK4S, MK3S+, Mini+) PrusaSlicer can insert a color change at a chosen Z height — the printer pauses and prompts you to swap the spool manually, then resumes automatically.
What is the minimum PrusaSlicer version?
2.7 or newer for reliable 3MF color-assignment import. Older versions may drop the color metadata and force you to reassign filaments by hand.
Which Prusa printer is best for this?
MK4 or MK4S give the cleanest first layer, which matters for the base plate. MK3S+ works equally well if you have MMU3. XL is overkill for a small QR object but its multi-tool head makes the color change instant.
Can I print several QR codes on the same plate?
Yes. Import multiple 3MFs, arrange them in PrusaSlicer, and slice — the wipe tower is shared, so per-object purging drops with quantity.
Does it work with Prusament or third-party filaments?
Yes. Any PLA or PETG that prints well on your Prusa will print this object well. Matte PLA and Prusament PLA are the safest bets for scannability.