Dual stage axial fan

3D printed dual stage axial fan. This was designed as an airbrush booth fume extractor, but it's so loud it will never be used as such.

DISCLAIMER: THIS THING IS NOT A TOY! I AM NOT RESPONSIBLE FOR ANY DAMAGE OR INJURY DERIVED FROM IT'S USE.

It's designed to spin at more than 20000rpm and it has enough kinetic energy at full speed to seriously hurt you. Take all safety precautions when operating it, including but not limited to the following;

• Wear personal safety equipment when operating it, expecially safety glasses and earplugs.
• Avoid brittle materials like PLA. Use PETG or ABS. Make sure yeld stress of the filament used is at least 25MPa.
• Do not change printing orientation of rotating parts.
• Make sure your printer is properly tuned and printed parts are solid. Do not use less than 4 perimeters and 25% infill for rotating parts, 2 perimeters and 15% infill for anything else.
• Ensure assembly is properly secured and shaft is balanced before running at full speed. Secure rotor blades to shaft with epoxy glue during assembly.
• At all times monitor vibration levels. Always make slow speed runs before throttling up to full speed.
• If using steel bearing, limit runs to a few minutes and periodically disassemble compressor stage to check for thermal damage to the shaft and bearing housings.
• Use only open or shielded bearing. Do not use sealed bearings as the heat generated by the seal could melt the shaft or the bearing housing.
• Do not overspeed. Maximum rotating speed is dependent on material and print settings and should properly be calculated or sperimentally determined beforehand for each unit.

Test runs videos: https://www.youtube.com/watch?v=qRQPLZ2gk0I

Print Settings

Printer Brand:

Prusa

Printer:

i3 MK3

Rafts:

No

Supports:

No

Resolution:

0.15mm

Infill:

15% - 25%

Filament: Prusa PETG / ABS

Notes:

Use no less than 4 external perimeters and 25% infill for rotating parts.
Use no less than 2 external perimeters and 15% infill for non rotating parts.

The design includes custom supports, but switch to build plate only automatically generated supports if you feel the results are not satisfactory with your printer/printer settings.

If using ABS monitor warping and part fit. I reccommend using ABS only for the shaft coupler and PETG for anything else.

Post-Printing

Use the provided STEP or Fusion 360 files to guide you during assembly. Pay close attention to rotor and stator blade orientation.

After assembling the rotor shaft, glue blades in place with epoxy glue and check proper shaft balance.

After assembling the rotor stage, gently hammer the front of the IGV and the rear of the 2nd stage stator to ensure proper bearing seating in their housing. Afterwards, check if excessive load is placed on the bearing to ensure proper assembly. Disassemble and reassemble if required.

Needed hardware is:

• 2x 6003 (17x35x10mm) open or shielded steel or ceramic bearings
• 44x 7.3xH5mm M5 plastic inserts
• 44x M5x16mm socket head cap screws
• 2x M3x16mm countersunk screw
• 1x 540 sized brushed motor capable of delivering 45W mechanical power or more at 20000rpm
• 1x DC19, DC20 or DC29 vacuum cleaner compatible HEPA filter

How I Designed This

Design and build summary available at https://imgur.com/a/ByC0AJW

Printed Parts Count

• 1x filter flange
• 1x intake section 1
• 1x intake section 2
• 1x shaft
• 5x stage 1 rotor blades
• 5x stage 2 rotor blades
• 1x front nut
• 1x rear nut
• 1x IGV
• 1x IGV bearing lock
• 2x stage 1 stator
• 1x stage 2 stator
• 2x casing
• 1x motor mount
• 1x shaft coupler
• 1x rear nut stator
• 1x nozzle
• 4x foot bracked
• 8x foot bracket spacer
• 4x foot collar
• 4x foot rod
• 4x foot