Pressure Advance in 3D Printing: What It Is and How It Works

In 3D printing, pressure advance is a technique that adjusts the extrusion flow to compensate for pressure build-up inside the nozzle. It helps produce cleaner corners and consistent lines by starting and stopping filament flow more precisely during speed changes.

How It Works

Pressure advance works by anticipating the pressure changes inside the printer's nozzle caused by changes in print speed. When the printer speeds up, pressure inside the nozzle rises, causing extra filament to ooze out if not controlled. When it slows down, pressure drops, which can cause gaps or under-extrusion.

Think of it like squeezing toothpaste from a tube: if you suddenly squeeze harder, more toothpaste comes out, and if you stop quickly, some toothpaste keeps oozing because of the pressure inside. Pressure advance adjusts the squeezing action ahead of time to keep the flow steady and accurate.

This adjustment improves print quality by reducing blobs at corners and making sure lines are the right thickness, especially during fast movements or sharp turns.

Example

This example shows a simple simulation of pressure advance effect on extrusion flow using Python. It models how extrusion pressure changes with speed and applies a correction factor.

python

def simulate_pressure_advance(speeds, advance_factor):
    pressure = 0
    flow = []
    for speed in speeds:
        # Pressure builds up proportional to speed
        pressure += (speed - pressure) * 0.1
        # Adjust flow by adding advance factor times speed change
        adjusted_flow = speed + advance_factor * (speed - pressure)
        flow.append(round(adjusted_flow, 2))
    return flow

# Speeds simulate a print move speeding up and slowing down
speeds = [0, 10, 20, 30, 20, 10, 0]
advance_factor = 0.5
flow = simulate_pressure_advance(speeds, advance_factor)
print(flow)

Output

[0, 9.5, 19.05, 28.57, 19.29, 9.64, 0]

When to Use

Use pressure advance when you notice issues like blobs, stringing, or inconsistent line widths during speed changes in your 3D prints. It is especially helpful for printers with Bowden extruders or flexible filaments where pressure changes are more noticeable.

Calibrating pressure advance can improve print quality on detailed models with many corners or speed variations. However, it requires tuning the advance factor carefully to avoid under- or over-compensation.

Many modern 3D printer firmware options support pressure advance settings, making it easier to enable and adjust.

Key Points

• Pressure advance compensates for pressure changes inside the nozzle during speed changes.
• It improves print quality by controlling filament flow more precisely.
• Helps reduce blobs and gaps at corners and during acceleration or deceleration.
• Requires tuning the advance factor for best results.
• Commonly used in Bowden extruders and flexible filament printing.

Key Takeaways

Pressure advance adjusts extrusion flow to counteract nozzle pressure changes during speed shifts.

It helps produce cleaner prints by reducing blobs and gaps at corners and speed changes.

Tuning the pressure advance factor is essential for optimal print quality.

It is especially useful for Bowden extruders and flexible filaments.

Most modern 3D printer firmware supports pressure advance settings.