How To Setup Marlin With 2 Hotends

Setting Up Marlin Firmware for Dual Extrusion: A Comprehensive Guide

This guide provides a step-by-step walkthrough on configuring Marlin firmware for a 3D printer with two hotends. Setting up dual extrusion can significantly expand your 3D printing capabilities, allowing for multi-color prints, soluble support structures, and more. However, it requires careful configuration of the firmware. This guide will walk you through the process, covering everything from initial setup to final testing. We'll focus on the key configuration changes needed to make your dual-extrusion setup work smoothly.

Understanding the Challenges of Dual Extrusion

Before diving into the configuration, it's crucial to understand the complexities involved in dual extrusion. These include:

• Independent Temperature Control: Each hotend needs its own independent temperature sensor and heater. The firmware must manage both independently.
• Extruder Movement: You'll need to control the movement of two extruders simultaneously or independently depending on the print. The firmware must coordinate their movements precisely.
• Filament Management: Preventing filament oozing and ensuring proper retraction for both extruders is essential. Careful configuration of retraction settings is vital.
• Firmware Selection: Choosing the correct Marlin version and configuration files is crucial. Make sure you use a version known to support dual extrusion.

Step-by-Step Marlin Configuration for Dual Extrusion

Let's assume you're starting with a standard Marlin configuration. Here's how to adapt it for dual extrusion:

1. Choose the Right Marlin Version: Ensure you're using a Marlin version explicitly supporting dual extrusion. Older versions might lack the necessary features. Check the Marlin GitHub repository for the latest stable release compatible with dual extrusion.

2. Hardware Configuration (Configuration.h): This file is where the magic happens. Here are the key changes you'll need to make:

• #define DUPLEX_XY or #define DUPLEX_LINEAR_ADVANCE: Select the appropriate setting based on your extruder setup. DUPLEX_XY is for independent extruders (more common), and DUPLEX_LINEAR_ADVANCE is used with Bowden setups where the extruders share a single X-axis.
• #define USE_TWO_EXTRUDERS: This is essential for enabling dual extrusion support.
• #define E0_STEP_PIN and #define E1_STEP_PIN: Define the step pins for each extruder motor.
• #define E0_DIR_PIN and #define E1_DIR_PIN: Define the direction pins for each extruder motor.
• #define E0_ENABLE_PIN and #define E1_ENABLE_PIN: Define the enable pins for each extruder motor.
• #define TEMP_SENSOR_0 and #define TEMP_SENSOR_1: Specify the type of temperature sensor used for each hotend (e.g., TEMP_SENSOR_100K_BETA).
• #define HEATER_0_PIN and #define HEATER_1_PIN: Define the pins connected to the heaters of each hotend.
• Adjusting Extruder Steps per MM (E0_STEPS_PER_MM and E1_STEPS_PER_MM): This is crucial for accurate extrusion. Calibrate each extruder individually to ensure accurate filament extrusion.

3. Extruder Calibration: This is crucial for accurate printing. Use a known length of filament and measure the extrusion distance to determine the correct STEPS_PER_MM value for each extruder. There are various methods available online for accurate calibration.

4. Retraction Settings: Proper retraction is critical to prevent stringing and oozing. You'll need to adjust retraction settings (RETROACTION_DISTANCE, RETROACTION_SPEED) for both extruders independently. Experiment to find the optimal settings for your specific filaments and printer setup.

5. Compile and Upload: Once the Configuration.h file is correctly configured, compile the Marlin firmware and upload it to your 3D printer's control board.

6. Testing: Start with simple tests to verify the functionality. Print small calibration cubes with each extruder individually. Then, try a simple dual-extrusion print to verify everything works correctly.

Advanced Configuration:

• Linear Advance: For smoother extrusion, consider enabling Linear Advance. This technique helps to compensate for the pressure variations in the extruder.
• Pressure Advance: Pressure advance is an alternative to linear advance that offers similar benefits.

Troubleshooting:

• Inconsistent Extrusion: Recalibrate the extruder steps per MM and check for clogs or other mechanical issues.
• Temperature Issues: Verify the wiring and sensor configuration.
• Filament Oozing: Adjust retraction settings and experiment with different speeds and distances.

By following these steps and carefully calibrating your settings, you can successfully configure Marlin for dual extrusion and unlock the advanced printing capabilities it offers. Remember to always consult the official Marlin documentation and community forums for the latest information and support. Happy printing!