Snapmaker U1: Slicer Settings for Perfect Multicolor Printing

The Snapmaker U1 with its four independent extruders and SnapSwap system opens up tremendous possibilities for multicolor printing. However, the quality of results largely depends on proper slicer configuration. In this article, we cover the key settings that help achieve clean color transitions, minimize waste, and eliminate visual artifacts. We will look at three slicers: the official Snapmaker Orca, standard OrcaSlicer, and PrusaSlicer with a community profile.

Snapmaker Orca — The Primary Slicer

Snapmaker Orca is a fork of OrcaSlicer, specifically adapted for Snapmaker printers. Currently in beta, it is primarily optimized for the U1. Compared to standard OrcaSlicer, Snapmaker Orca includes built-in profiles for the U1, remote monitoring and printer control support, and pre-configured tool-change G-code.

Installation and Initial Setup

Download Snapmaker Orca from the official site at snapmaker.com/snapmaker-orca. On first launch, select the Snapmaker U1 printer — printer, filament, and process parameters will load automatically. The slicer organizes settings into three preset categories: Printer, Filament, and Process, each of which can be configured independently.

Before starting to print, it is recommended to run the built-in calibrations. Open the Calibration menu and sequentially perform Flow Rate, Pressure Advance, and Temperature Tower calibrations. This is especially important when using filaments from different manufacturers — default profiles are tuned for average values.

Differences from Standard OrcaSlicer

Standard OrcaSlicer can also be used with the U1, but you will need to manually configure the printer and tool-change G-code. Snapmaker Orca provides ready-made integration: automatic toolhead parking, native purge routines, and extruder preheating are all implemented out of the box. Unless you plan deep customization, Snapmaker Orca is the recommended choice.

Key Quality Settings

VFA Elimination (Vertical Fine Artifacts)

VFA — Vertical Fine Artifacts — appear as regular ripple patterns on the surface of a part. On the U1, they can be completely eliminated for free by changing three slicer parameters. The trick is to find the speed at which the vibration frequency moves outside the visible range.

Before changing settings, run the built-in VFA test through the Calibration menu in Orca. Set the range from 100 to 300 mm³/s. Important: temporarily set the Max Volumetric Speed in filament settings to an arbitrarily high value (e.g., 200 mm³/s) to avoid limiting flow rate during testing.

Based on your test results, configure the following parameters:

• Outer Wall Speed — set to at least 210 mm/s (determine the exact value from your VFA test). At this speed, vibrations move into a range invisible to the eye
• Inner Wall Speed — also 210 mm/s for consistency
• Wall Printing Order — Inner/Outer/Inner. This mode prints inner walls first, then the outer wall, then inner walls again, improving surface quality
• Outer Wall Line Width — 0.4 mm. The line width must support adequate volumetric flow at the selected speed
• Inner Wall Line Width — 0.4 mm

Z-Hop: Eliminating Knocking

Many U1 users encounter a characteristic knocking sound on the Z-axis during printing. This noise is caused by the Z-hop type setting and can lead to layer shifting. The solution is simple: for each of the four extruders, change the Z-hop type from Auto to Normal.

In Snapmaker Orca, open the settings for each extruder (Extruder 1–4) and find the Z Hop Type parameter. The default is Auto — change it to Normal and save. Then re-slice your model. Additionally, verify that the Z-axis lead screw is lubricated — quarterly maintenance is recommended.

Prime Tower Optimization

The Prime Tower is an essential element of multicolor printing. It stabilizes extrusion after a color change by purging residual filament from the nozzle. However, the default settings in Snapmaker Orca are significantly overestimated, leading to excessive material waste. Optimizing a few parameters can reduce the tower size dramatically without sacrificing quality.

The most critical parameter is Minimal Purge on Wipe Tower. The default value of 60 mm³ was the primary cause of oversized towers. Reducing it to 10 mm³ radically decreases filament consumption during the first tool change on each layer.

A tower width of 20 mm and prime volume of 15–18 mm³ ensure reliable extrusion without excess. The Rectangle shape provides structural stability. If you are printing tall parts or using filaments prone to warping (PETG, ABS), increase the prime tower brim width to 1.5–2x the model's brim width.

Working with MakerWorld Models

MakerWorld is the largest library of multicolor models, but its .3mf files are optimized for Bambu Lab printers. Opening these files directly in Snapmaker Orca can overwrite your printer settings. There are two approaches to working with these models.

Importing Geometry Only

Use File → Import → Import 3MF/STL to load only the model geometry without Bambu Lab settings. This approach works for simple models, but you will lose color assignments — all parts will be assigned to active filaments.

Converting with Color Preservation

The online converter at bl2u1.nbn.cat automatically transforms Bambu Lab .3mf files into Snapmaker U1 format while preserving color painting data. The tool changes printer settings, applies the 0.20mm Standard profile, remaps filament types to U1-compatible profiles, and enables Tree Supports if they were present in the original. Open the converted file in Snapmaker Orca for final slicing.

An offline version of the converter is also available on GitHub (josuanbn/bl2u1) for local use. Keep in mind the U1's limitation of 4 filaments/colors maximum. Models with more colors will require consolidation.

PrusaSlicer Alternative

For those who prefer PrusaSlicer, the community has developed a profile for the Snapmaker U1 with multicolor printing support. The profile is available on GitHub: joseosanchez/Snapmaker-U1---Prusa-Slicer-Profile. It restores correct tool-change behavior and closely matches OrcaSlicer's routines.

What the Profile Includes

• Printer configuration with 4 extruders
• Custom tool-change G-code with Snapmaker's native purge routine
• Console logging to Fluidd via RESPOND commands
• Python post-processing script for extruder preheating

Preheat Post-Processing Script

The main issue with PrusaSlicer on multi-extruder printers is idle time while heating an inactive nozzle. Unlike OrcaSlicer, PrusaSlicer cannot preheat the next extruder in advance. The included Python script solves this problem using temporal lookahead: it calculates actual printing time (rather than counting G-code lines) and initiates heating at precisely the right moment.

PrusaSlicer Profile Installation

1. Download the .ini configuration file from the repository and import it into PrusaSlicer
2. Verify that 4 extruders are selected and MMU mode is disabled
3. Save the Python script to a permanent directory on your drive
4. Add this line at the end of Start G-code: ;----- End Start_gcode ------
5. In Print Settings → Post-processing, specify the script path: "python.exe" "script.py" 40 (the number at the end controls the preheat lead time in seconds)

Summary: Recommended Settings Checklist

1. Install Snapmaker Orca and run Flow Rate, Pressure Advance, and Temperature Tower calibrations
2. To eliminate VFA: Outer Wall Speed ≥ 210 mm/s, Wall Order — Inner/Outer/Inner, Line Width — 0.4 mm
3. Z-hop Type — Normal for all four extruders
4. Prime Tower: Width 20 mm, Prime Volume 15–18 mm³, Minimal Purge 10 mm³, Rectangle
5. For MakerWorld models, use the bl2u1.nbn.cat converter
6. If PrusaSlicer is needed — use the community profile with post-processing for preheating

With the right settings, the Snapmaker U1 produces multicolor prints comparable to the best solutions on the market. The SnapSwap system with four independent toolheads combined with a properly configured slicer minimizes waste, eliminates artifacts, and unlocks the printer's full potential.