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Heatbed & PSU Assembly

In this chapter, we will prepare and mount the two main power components of the printer: the Heatbed, where your prints will be built, and the Power Supply Unit (PSU), which provides all the energy for the machine.

Pay Close Attention to Wiring

This chapter involves connecting high-power electrical components. Please follow the instructions for polarity and wiring precisely to avoid damaging your printer or creating a safety hazard.

Part 1: Assembling the Heatbed Cables

First, we will securely attach the main power cable to the heated bed.

Step 1: Preparing the Heatbed Power Cable

Gather all the necessary components for this crucial connection.

  • Parts needed:
    • Heatbed (1x)
    • Heatbed power cable (1x, with red and black wires)
    • M3x10 screw (2x)
    • M3 washer (2x)
    • M3nN nyloc nut (2x)

Step 2: Attaching the Power Cable

CRITICAL: Check Wire Polarity

Connecting the wires with the wrong polarity will damage your printer's electronics. Double-check every connection. * The BLACK wire must connect to the terminal labeled GND. * The RED wire must connect to the terminal labeled VCC.

  • Action:

    1. Place the ring terminal of the black wire over the heatbed pad labeled "GND".
    2. Place a washer on top of the ring terminal.
    3. Insert an M3x10 screw through the washer and the ring terminal into the heatbed.
    4. On the other side of the heatbed, secure it with an M3nN nyloc nut. Use pliers and an Allen key to tighten it firmly.
    5. Repeat this exact process for the red wire, connecting it to the pad labeled "VCC".

  • Final Adjustment: Before the final tightening, gently bend the two metal ring terminals so they are angled slightly towards each other. This will help them fit inside the cable cover. Now, tighten both screws firmly.

Heatbed Wiring Polarity   Heatbed Wiring Polarity  

Illustration showing the correct polarity: the black wire connected to GND and the red wire to VCC.

Part 2: Assembling the Heatbed Cable Cover

Now we will install the printed cover that protects the solder joints and manages the cable strain.

Step 3: Preparing the Cable Cover Parts

  • Parts needed:
    • Heatbed-cable-cover (1x, the larger printed part)
    • Heatbed-cable-cover-clip (1x, the smaller printed part)
    • Textile sleeve (1x)
    • Various M3 screws and nuts.
  • Action: Take the smaller Heatbed-cable-cover-clip and insert two M3n nuts into its slots.

Step 4: Mounting the Main Cable Cover

  • Action: Place the larger Heatbed-cable-cover onto the heatbed, aligning its hole with the central mounting hole on the bed's power terminal section. Secure it with an M3x10 screw and an M3nN nyloc nut.

Proper Thermistor Cable Management

The thin black cable already attached to the bed is the thermistor, which measures the bed's temperature. * Action: Ensure there is some slack in this cable underneath the cover. If it's too tight, it could break when the bed moves. * Action: To keep it neat, wrap the thermistor cable a few times around the main power cable bundle.

Step 5: Wrapping and Securing the Cable Sleeve

  • Action: Take the textile sleeve and begin wrapping it around the power and thermistor cables, starting from right behind the cable cover. Slide the first few centimeters of the sleeve inside the cover.
  • Action: Take the smaller Heatbed-cable-cover-clip that you prepared earlier and place it on top of the main cover.

Do Not Pinch the Thermistor Wire!

The clip has a small channel or cutout specifically for the thermistor wire. Make sure the wire is seated neatly in this channel before you tighten the screws. Pinching this wire will damage it.

  • Action: Secure the clip with two M3x10 screws, tightening them evenly. This will clamp the textile sleeve and wires firmly in place.

Assembled Heatbed Cable Cover   Assembled Heatbed Cable Cover  

The final assembled heatbed cable cover, with the textile sleeve and wires securely clamped.

Step 6: Finalizing the Cable Wrap

  • Action: Continue wrapping the textile sleeve neatly around the entire length of the heatbed cable bundle. When finished, you can twist the sleeve slightly to make it tighter and more uniform.

Step 7: Mounting the Heatbed

Now we will mount the prepared heatbed assembly onto the Y-carriage.

  • Parts needed:
    • M3x12b screw (9x)
    • 6x6x3t spacer (9x)
  • Action:
    1. Push the Y-carriage to the front of the printer. Place the heatbed on top of it.
    2. Start with the center hole. Place one spacer on the center hole of the Y-carriage. Align the center hole of the heatbed with it and insert one screw. Do not tighten it fully yet.
    3. Using pliers, carefully place the other eight spacers on their corresponding holes on the Y-carriage, between the carriage and the heatbed.
    4. Insert the remaining eight screws into their holes.

Correct Tightening Sequence for a Flat Bed

To ensure the bed is mounted flat and without stress, tighten the nine screws in a specific order: 1. Tighten the center screw first. 2. Tighten the four screws on the main edges (front, back, left, right). 3. Finally, tighten the four corner screws.

Heatbed Spacer Placement   Heatbed Spacer Placement  

Illustration showing the placement of the spacers between the Y-carriage and the heatbed.

Step 8: Preparing the PSU Parts

It's time to prepare the Power Supply Unit (PSU), the component that powers the entire printer.

  • Parts needed:
    • 24V Power Supply Unit (PSU) (1x)
    • Power Panic cable (1x)
    • PSU power cables (2x pairs)
    • M4x10r screw (2x)
    • M3x10 screw (2x)
  • Note: The PSU is designed to work worldwide and automatically switches to the correct local voltage.

Step 9: Mounting the PSU to the Frame

  • Action: Turn the printer so the rear side is facing you. Loosely screw two M3x10 screws into the printed PSU holders on the bottom extrusion.
  • Action: Slide the PSU onto these screws. You may need to adjust the spacing of the holders so they align with the mounting holes on the side of the PSU.
  • Action: Now, align the mounting holes on the front of the PSU with the corresponding holes on the printer's vertical frame. Insert and tighten the two M4 screws.
  • Action: Before the final tightening, ensure the PSU is pressed firmly against both the bottom extrusion and the vertical frame. Once everything is aligned, fully tighten all the mounting screws (both the M3 and M4 screws).

Step 10: Connecting Power Cables to the PSU (CRITICAL)

This is a critical step that requires your full attention. Incorrect wiring here can damage the printer.

CRITICAL: High Voltage - Check All Connections

  • Triple-check that you are connecting the wires correctly.
  • The terminals on the PSU are clearly marked for positive (+) and negative (-) polarity.
  • The layout is: +, +, -, -.
  • Ensure the bent part of the metal "fork" connectors on the cables is always facing up.

PSU Terminal Polarity   PSU Terminal Polarity  

A close-up of the PSU terminals, highlighting the correct polarity (+ + - -).

Step 11: Connecting the Main Power Cables

This step involves connecting the two pairs of power cables to the PSU terminals. These cables will power your mainboard and your heated bed.

CRITICAL: Double-Check Your Wiring

This is the most critical wiring step of the entire build. Incorrect connections here can damage your electronics. The polarity on the PSU is (+, +, -, -). * Ensure the bent part of the cable's fork connector is facing up, away from the PSU casing. * The steel washer must be above the fork connector when you insert the screw.

  • First Cable Pair:
    1. Connect the RED wire to the FIRST (+) terminal from the left.
    2. Connect the BLACK wire from the same cable to the THIRD (-) terminal from the left.

  • Second Cable Pair:

    1. Connect the RED wire to the SECOND (+) terminal from the left.
    2. Connect the BLACK wire from the same cable to the FOURTH (-) terminal from the left.

  • Action: Use a Philips screwdriver to tighten all four screws firmly. A loose connection here can cause serious problems.

PSU Final Wiring   PSU Final Wiring  

The final correct wiring on the PSU terminal block.

Step 12: Connecting the Power Panic Cable

The Power Panic feature allows your printer to recover from a sudden loss of power.

  • Action: Take the Power Panic cable and connect it to its dedicated two-pin port on the PSU.
  • Action: Gently bend the cable and route it along with the main power cables towards the other side of the printer, where the electronics housing will be.

Handle with Care

The connector on the Power Panic board is small and can be fragile. Avoid pulling or straining this cable until the printer is fully assembled.

Step 13: Heatbed and PSU are Finished!

The main power systems of your printer are now fully assembled and mounted.

  • Action: Take a final look at your assembly and compare it to the reference pictures. Ensure all screws are tight and all cables are routed neatly.

Do Not Place the Steel Sheet on the Heatbed Yet

You will be instructed to place the flexible steel sheet on the heatbed during the initial calibration wizard after the assembly is complete. Leave it off for now.

On to the Final Chapter!

Excellent work! With the power systems in place, you are ready for the final assembly chapter: connecting all the electronics.