Choose one of the blowers below, or use any air source more powerful than the normal blower.

Normal blower

Delta BFB0724H (2-wire)

• 2.88W, 11.3 CFM, 0.48 inH2O

• An economic baseline.

High-power blower

WM7040-24v CPAP blower with driver board

• 65W, 8.5CFM, 29.5 inH2O

• 25% fan speed for almost all prints

• Fan port of printer control board (eg. BTT Octopus) must be configured to output 12V PWM signals, 24V is not allowed.

• Keyword: CPAP centrifugal blower 70mm 24V

PWM-to-voltage module

Resistor 1/4W 10K ohm (x1)

16AWG wire (30~50cm)

Air hose

• Smooth inside, plastic helix reinforced outside hose.

• 16mm ID, 1.5m long will be more than enough for SK-Tank.

• The diameter is customizable if you modify the blower output and the duct intake.

• Keyword: PVC plastic reinforced hose

Heatsink fan

• 4010 24V fan (x1)

Hardwares

• Bolt M3 x 6 (x1)

• Bolt M3 x 8 (x10)

• Bolt M3 x 15 (x2)

• Washer M3 x 8 x 1.0 (x13)

• Nut M3 (x13)

Assembly

Download the STLs from Breezer GitHub repository

• Duct

• Cover

• Duct mount

• Intake

• Blower accessory

• Nozzle guide

• Hotend rigid mount (optional)

4010 heatsink cooling fan

Actions

Press M3 nuts into the indentations of the cover, and face the sticker side of the 4010 fan to the extruder.

Assemble the cover and the duct as shown in the picture.

Adjust the height of the duct with the nozzle guide. When both the nozzle and the duct touch the guide, the output airflow aims the nozzle.

Probe Offset

2 variations of Breezer ducts with probe mount are provided, with the offsets:

BLTouch: (+34, 0)

Inductive sensor: (+35, 0)

WM7040 Blower Wiring

The WM7040 blower is a 65W high power 3-phase brushless DC motor which needs an extra driver board. 25% fan speed is enough for most cases.

This driver board takes 0~5V analog signal as speed control input, but the printer control board outputs PWM signals, so another PWM-to-voltage converter is needed.

In this implementation a printer control board with a 12V fan port is a must to send PWM signals as speed control to the converter board.

Here BTT Octopus is used. Note that the Octopus generates PWM signal at the FAN- pins, not the FAN+ pins.

• WM7040 driver board

• PWM-to-voltage converter

• 1/4W 10k ohm resistor (x1)

• 16 AWG wire

Actions

Make 4 customized wires as marked in the picture and connect those pins.

Exam

• 24V fan port voltage is not allowed. Might burn the converter.

• The FAN- pin of fan port is used, not FAN+.

• Check your wiring or soldering with an ohm meter.

Tuning for WM7040 Blower

• Klipper: increase the maximum temperature difference (in Celsius) to a target temperature that is considered in range of the target. The blower is too powerful.

[verify_heater extruder]
hysteresis: 10

• Use 25% or lower fan speed for PID tuning. The hotend cannot heat up with higher fan speed.

• Hotend silicone sock is a must

Intake & Mount for SK-Cube

SK-Cube owner Budhi created an angled intake and a blower mount for the limited chamber of the Cube. Visit Printables for the STL files.

SK-Cube 7035 Blower fan via CPAP tube part cooling mod for Breezer Hotend

https://www.printables.com/model/284423-sk-cube-7035-blower-fan-via-cpap-tube-part-cooling