Gel Printing with Syringe Extruder

Overview

This guide walks you through the steps of 3D gel printing using the syringe tool on a Science Jubilee machine.

Initial Setup

Ensure the build plate is clear before starting.

from science_jubilee.Machine import Machine
from science_jubilee.tools.SyringeExtruder import SyringeExtruder

m = Machine(address="192.168.1.2")

To home the machine:

# m.home_all()  # Uncomment and run only if needed

Load the Syringe Tool

Make sure the tool_index and tool_name match the settings in your config.g (check in Duet Web Control).

syringe_index = 10000           # Update this to match your setup
syringe_config = "10cc_syringe" # Use predefined configuration
syringe_name = "Syringe"

syringe = SyringeExtruder(
    index=syringe_index,
    name=syringe_name,
    config=syringe_config
)
m.load_tool(syringe)

Prepare your F-127 material with instructor guidance.

Calibrate Z Offset

Precise Z-offset calibration is critical for successful gel printing.

1. Pick up the syringe tool:

m.pickup_tool(syringe)

2. Move to center and drop to Z = 0:

m.move_to(x=150, y=150)
m.move_to(z=0)

This will not reach the actual bed surface. Slowly lower the nozzle until it just touches the glass plate.

z_offset = -1.5  # Adjust slowly to avoid collisions
m.move_to(z=z_offset)

3. Calculate and apply temporary Z-offset:

starting_offset = m.tool_z_offsets[m.active_tool_index]
real_z_position = float(m.get_position()["Z"])
new_z_offset = starting_offset - real_z_position

m.set_tool_offset(tool_idx=m.active_tool_index, z=new_z_offset)

# Confirm current position is now z = 0
m.get_position()['Z']

Always calibrate to the glass plate, not directly to the bed.

Prime the Nozzle

Before printing, extrude material to fill the nozzle.

m.pickup_tool(syringe_0)
m.move_to(z=25)  # Raise to allow cleaning
syringe_0.move_extrude(e=1)  # Repeat if needed

Load and Print G-code

G-code Helper Functions

def load_gcode(file_path):
    try:
        lines = []
        with open(file_path, 'r') as file:
            for line in file:
                lines.append(line.strip())
        return lines
    except FileNotFoundError:
        print(f"File '{file_path}' not found.")
        return None
    except Exception as e:
        print(f"An error occurred: {e}")
        return None

def print_gcode(gcode):
    for line in gcode:
        if line and not line.startswith(';'):
            print(line)
            m.gcode(line)

Start Printing

Remove the glass plate while the Z-axis homes, then place it back before printing begins.

gcode = load_gcode("cylinder-20mm.gcode")
print_gcode(gcode)

Park the Tool

After printing:

m.park_tool()

Custom Gel Printing: Toolpath Example

You can also script your own extrusion toolpath.

Raised Test Cube

m.pickup_tool(syringe_0)

z = 0
layer_height = 0.2
z_off = 0
start_x = 150
start_y = 150
side_length = 20

m.move_to(x=start_x, y=start_y, z=z)

for layer in range(40):
    syringe_0.move_extrude(x=start_x + side_length, y=start_y, z=z, multiplier=1)
    syringe_0.move_extrude(x=start_x + side_length, y=start_y - side_length, z=z + z_off, multiplier=1)
    syringe_0.move_extrude(x=start_x, y=start_y - side_length, z=z + z_off, multiplier=1)
    syringe_0.move_extrude(x=start_x, y=start_y, z=z, multiplier=1)
    z += layer_height
    z_off += 0.1