Chapter 03: The Build Plate

This chapter covers the preparation and installation of the heated bed assembly. This component is critical for printing materials like ABS, as it ensures good first-layer adhesion and prevents warping.

Step 1: Prepare the Plate

The first step is to apply the magnetic sheet and the heater mat to the aluminum build plate.

1. Clean Surface: Thoroughly clean the top surface of the aluminum plate with isopropyl alcohol.
2. Apply Magnet: Carefully apply the self-adhesive magnetic sheet to the clean top surface. Use a small roller or a plastic card to press it down firmly, removing any air bubbles.
3. Apply Heater: Flip the plate over and apply the silicone heater mat to the bottom side, ensuring it is centered.

A two-part illustration showing the magnetic sheet being applied to the top of the plate and the silicone heater being applied to the bottom.

Step 2: Install Safety Components

Critical Safety Step

The thermal fuse and ground wire are essential safety features. Do not skip these steps. The thermal fuse protects against dangerous overheating, and the ground wire protects against electrical shock.

1. Thermal Fuse: The thermal fuse is wired in-line with the heater's power wires. Mount it to the designated tapped hole on the bottom of the build plate.
2. Thermistor: Attach the bed thermistor to the center of the plate. This sensor monitors the bed temperature.
3. Ground Wire (Protective Earth): Securely fasten a ground wire with a ring terminal to the build plate's designated ground point. This wire must be connected to the frame and your power supply's earth connection.

A close-up of the underside of the build plate, showing the attachment points for the thermal fuse, thermistor, and the protective earth ground wire.

Step 3: Mount the Bed Assembly

The heated bed is mounted to the two support extrusions you installed in the frame chapter.

1. Install Spacers: Place three M3 T-Nuts into the channels of the bed support extrusions. Thread M4 thumb nuts onto the M3x16 SHCS screws; these thumb nuts will act as heat-resistant spacers.
2. Mount the Plate: Place the build plate assembly onto the three mounting points.
3. Tighten Carefully: Fully tighten only one of the three mounting bolts. Leave the other two slightly loose. This allows the aluminum plate to expand and contract with heat changes without warping.

The fully prepared build plate being lowered onto the three mounting points on the bed support extrusions.

Finally, route the heater, thermistor, and ground wires through the opening in the deck panel to the electronics compartment below. Ensure the front edge of the build plate is positioned correctly, about 38mm from the front of the frame.