Crayon

An Air/Liquid-Cooling

High-flow Hotend

v0.95 (11/22/2024)
Add an extra wiring method

Crayon hotend is available at

Liquid-Cooling Setup

Attach the front and rear aluminum liquid-cooling covers, and the silicone pads to the heat sink. The heat sink also acts as a liquid channel.

The thread on the hose connector to the liquid-cooling covers are relatively fragile, due to its hollow structure. Do not fasten it hard and always apply thread locker in case that you need to re-assemble the connector.

Place the USB pump within about 30cm higher or lower than the heat sink, so the water can circulate in the channel. Without a radiator, a simple tank with 3~5 liter of water is enough for normal operation.

Do water leakage test BEFORE mounting Crayon to your extruder! Place a piece of tissue near all hose joints and check leaks.

Mounting

The heat sink is a rigid-mount with M2.5x0.45 threads holes.

The STEP files of the air and liquid cooling heat sinks, and the lower printed cap are provided in Crayon GitHub repository.

Before First-Time Use

Remove the lower cap and fasten the nozzle when it is heated up.

Hold the hotend with a plier or a wrench at the inner heat block, not the outer stainless steel heat shield.

The STL and STEP files of the lower cap is in Crayon GitHub repository.

Wiring

Crayon equips with two 24V 70W ceramic heaters, totally 140W, so a common heater port on a control board is usually not enough for it.

Crayon must be directly powered by a power supply unit, and controlled by a heater port and a DC-DC SSR.

If your control board has a standalone power (input) for the bed heater and a built-in MOSFET-controlled bed heater port (output), wire it as shown below and do according modification in your firmware configs. Make sure the output port provides enough margin for the 24V 140W heaters of Crayon hotend.

Assembly

Apply thread locker to all threads on the cold side only, including the heat sink, heat shield and front/rear liquid covers.

The inner heat block is sustained by two M2x20 bolts to the outer heat shield. There is also one set screw slightly pushing the heat break tube against the heat sink.

If you need to adjust the position of the heat block,

Loosen the M2 nuts by fixing the M2x20 bolts.
Gradually and alternately turn the two M2x20 bolts to adjust the position of the heat block.
Fasten the M2 nuts by fixing the M2x20 bolts.

Do not push the heat block off the center too much. This could bend the heat break tube.

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