Brief Overview

Pressure Advance is a firmware feature that compensates for filament elasticity and flow dynamics within the hotend. Properly tuning Pressure Advance improves print quality, particularly regarding sharp corners and the appearance of the print seam.

Introduction

This guide explains how to understand, adjust, and calibrate the Pressure Advance setting for your 22 IDEX using PrusaSlicer. The goal is to fine-tune extrusion behavior to achieve sharper corners and minimize seam artifacts (bulging or gaps). While we provide well-tested default values in our PrusaSlicer profiles (optimized for a 0.4 mm nozzle), factors like nozzle diameter and filament moisture content can necessitate adjustments for optimal results.

Working Principles

At its core, you can think of Pressure Advance as a smart way the printer adjusts filament flow just before speed changes, somewhat like dynamically altering retraction during a print move.

Tools & Materials

• Computer (with PrusaSlicer installed)
• 22 IDEX (connected and operational)
• Filament (the specific type you are calibrating)
• Calibration Model (e.g., a simple cylinder)

Safety & Pre-checks

• Before Printing Run Print Check List
• Have a suitable calibration model file (e.g., a 20mm cube .stl) ready.

Warning: Warning: The printer's nozzle and bed can reach high temperatures. Avoid touching hot components during operation.

Step-by-Step Instructions

1. Understanding Pressure Advance Effects

Pressure Advance primarily affects two visual aspects of your print:

• Corners: Properly tuned Pressure Advance results in sharp, well-defined corners. If corners are rounded, Pressure Advance might be too high. If corners have excessive bulging or overshoot, it might be too low.
• Seam: The seam is where the printer starts and stops extrusion on each layer.
  • If the seam bulges outward significantly from the print surface, Pressure Advance is likely too low (or off), causing excess pressure release at the layer end.
  • If there is a gap or depression at the seam, Pressure Advance might be too high, retracting too aggressively before the layer change.

2. Locating the Pressure Advance Setting in PrusaSlicer

The Pressure Advance value is set via custom G-code within the filament profile:

1. Open PrusaSlicer.
2. Go to the Filament Settings tab.
3. Select the filament profile you wish to adjust from the dropdown menu.
4. Navigate to the Custom G-code section in the left-hand panel.
5. Locate the Start G-code text box.
6. Look for a line M572 D0:1 S0.035. This command sets the Pressure Advance value. If the line is not present, the printer will use its firmware default or none if not configured.

3. Baseline Values and Adjusting for Nozzle Size

Our default profiles often use a Pressure Advance value suitable for common materials with a 0.4 mm nozzle.

• Default (0.4 mm Nozzle): A typical starting value for many plastics (like PLA, ABS) is S0.035.

• Larger Nozzles (0.6 mm): Pressure effects are less pronounced with larger orifices. You should decrease the Pressure Advance value significantly. Try starting around S0.01 or even disabling it completely by setting it to S0.0.

• Very Large Nozzles (0.8 mm and up): It is generally recommended to disable Pressure Advance entirely for very large nozzles set to S0.0.

Warning: Important: To disable Pressure Advance, you must explicitly set the value to zero using the G-code command: M572 S0.0 Simply deleting the M572 line from the custom G-code will cause the printer to revert to its built-in firmware default (which might be 0.035 or another non-zero value), not disable it.

4. Calibration Procedure

1. Evaluate: Carefully examine the corners and the seam of the printed model.

Seam Bulging / Overshooting Corners? -> Pressure Advance might be too low. Increase the S value slightly (e.g., from 0.035 to 0.045).

Seam Gap / Rounded Corners? -> Pressure Advance might be too high. Decrease the S value (e.g., from 0.035 to 0.010, or from 0.01 to 0.0 for larger nozzles).

2. Iterate: Modify the M572 S<value> in the filament's start G-code, re-slice, and print again.

Note: Tip: Use a calibration model for Pressure Advance tuning (like a Cylinder or Square) for faster iteration.

3. Save Profile: Once satisfied, save the modified filament profile.

Troubleshooting & FAQs

1. Q: I deleted the M572 line, but Pressure Advance still seems active?
   • A: Deleting the line causes the printer to use its firmware-defined default value. To explicitly disable Pressure Advance, you must add or edit the line to be M572 S0.0 in the filament's start G-code.
2. Q: How does wet filament affect Pressure Advance?
   • A: Moisture in filament changes its extrusion properties, often making it stringier or oozier, which can interfere with Pressure Advance calibration. Always use dry filament for consistent results. If you suspect moisture, dry your filament according to the manufacturer's recommendations before tuning. Wet filament typically requires lower Pressure Advance values.
3. Q: Can Pressure Advance be set too high?
   • A: Yes. Excessively high values can cause gaps at the seam, filament grinding in the extruder due to rapid movements, and potentially introduce other artifacts.
4. Q: Where can I find dedicated Pressure Advance calibration models?
   • A: Search on 3D model repositories (like Printables, Thingiverse) for "Pressure Advance test" or "Pressure Advance tower". These models often incorporate features designed to make the effects more obvious.

Conclusion & Additional Resources

Fine-tuning Pressure Advance is a key step towards achieving high-quality prints, especially those with sharp geometric features. Remember to save your tuned settings as a new filament profile in PrusaSlicer for future use. Performing a test print with a model representative of your typical prints is recommended to confirm the calibration.

• Understanding Pressure Advance (Linear Advance) (Link to Marlin firmware documentation on the feature, often called Linear Advance)
• Contact Vision Miner Support