Part cooling duct for BIQU H2 using 5015 fan.
Orient the duct for printing upright as it will be used. Print using supports under the full base I painted support requirements on the full base using PrusaSlicer.  Supports are not required for the vertical screw mount plates.

I used PLA3D850 filament since it has a higher heat resistance than regular PLA and is stiffer than PETG. Nonoilen filament would be even better for heat.
Criteria for the design:
- 5015 blower fan
- access to and easy viewing of the BIQU H2 extrusion thumbwheel
- access to the filament loading lever
- good visibility of the nozzle for live z offset adjustment
- adjustable z height to accommodate nozzles with a slightly different length
- get wrenches on the nozzle and heat block without having to remove the cooling duct

In addition to the cooling duct the following are required.
- 2x M3 6mm screws
- 7x M3 flat washers
- 2x M3 25mm screws
- 2x M3 nylok hex nuts (or regular nuts with lock washers)
- 1x 5015 blower fan (24V)

To test the flow I put some instant coffee in the bowl of water to make the water surface easier to see.
The pictures of the flow are for the following Fan settings:
000% - 0
003% - 8
006% - 16
012% - 32
025% - 64
050% - 128
100%  - 255

BIQU H2 5015 Cooling Duct

Cooling Duct

Parts for rigid mount for BIQU H2 extruder for Ender 3V2.  Plate is a modified plate purchased on Amazon, two holes for the BIQU H2 are required to be drilled.  Note the Z carriage needs to be cut back below the 2020 extrusion for the X carriage to accommodate the lower roller bolt on the X carriage.  The cut back dimensions are not critical and can be done with a hacksaw and file, see the picture.
Purchased plate was...
balikha 3D Printer Alloy Direct Drive Extruder Plate for Ender-3/V2/CR-10
The plate requires the X and Y carriage stops to be adjusted.  Simple 3D printed spacers are used.  There is an X carriage stop for use with a BLTouch and one for no BLTouch.
I printed the spacers in PLA3D850 because of its higher heat resistance.  That way I can use them in a heated enclosure.

Extended X carriage Y-stop Spacer.stl

Extended X carriage BLTouch Mount.stl

Extended X carriage X-stop Spacer.step

Extended X carriage Y-stop Spacer.step

Extended X carriage X-stop Spacer.stl

Extended X carriage BLTouch Mount

BLTouch Mount

Parts for rigid mount for BIQU H2 extruder for Ender 3V2.  Plate is a modified plate purchased on Amazon, two holes for the BIQU H2 are required to be drilled.  Note the Z carriage needs to be cut back below the 2020 extrusion for the X carriage to accommodate the lower roller bolt on the X carriage.  The cut back dimensions are not critical and can be done with a hacksaw and file, see the picture.
Purchased plate was...
balikha 3D Printer Alloy Direct Drive Extruder Plate for Ender-3/V2/CR-10
The plate requires the X and Y carriage stops to be adjusted.  Simple 3D printed spacers are used.  There is an X carriage stop for use with a BLTouch and one for no BLTouch.
I printed the spacers in PLA3D850 because of its higher heat resistance.  That way I can use them in a heated enclosure.


dtdakin

BIQU H2 5015 Cooling Duct

Extended X carriage Y-stop Spacer.stl

Extended X carriage BLTouch Mount.stl

Extended X carriage X-stop Spacer.step

Extended X carriage Y-stop Spacer.step

Extended X carriage X-stop Spacer.stl

Extended X carriage BLTouch Mount

Extended X carriage mod for BIQU H2

Extended X carriage Plate.3mf

Extended X carriage X-stop Spacer.3mf

Extended X carriage Y-stop Spacer.3mf

Extended X carriage BLTouch Mount.3mf