This fantasy themed bladeless fan was designed, sculpted, SLS printed, and hand-painted to showcase the advanced capabilities of SLS printing technology, exclusively for the MyMiniFactory Sinterit Lisa design challenge.
*** VIDEO ***
[These are higher quality versions compared to the ones I uploaded to Twitter]
Watch the evolution of the design from 3D concept to SLS print to hand-painted creation:
Peek inside the design to see how it works!
*** DESIGN PHILOSOPHY ***
The fan is a marriage of sophisticated mechanical design and creative aesthetics that demonstrates the potential of SLS printing for functional and artistic projects alike. It has a minimum of parts, and the moving components are printed in place. The design was made with the MyMiniFactory community in mind, having only two non-printed parts, both of which are inexpensive and widely available (links below). I ordered an SLS print to prove the legitimacy of the design.
*** DESIGN DETAILS ***
Cross-sectional images and videos (links above) are included to show the fan’s inner workings since the fan was printed essentially as one-piece that cannot be disassembled, and visibility inside through the upper and lower doors is limited.
As shown, the fan includes a custom designed, mixed-flow impeller suspended in a shroud. The shroud has an open lower end to allow air to enter the air inlet of the impeller. The upper end of the shroud is integrally formed with an air duct that guides the high velocity air produced by the impeller into the base of the hollow ring. The hollow ring includes an air outlet formed as a 1mm annular slot at the inner diameter of the ring. The fan generates a ring-shaped jet of essentially laminar air flow that pulls air through the center of the ring creating an air-multiplying effect.
The impeller is driven by a simple DC motor that runs on a 9V battery (or 6 AA’s or AAA’s). The bottom of the impeller connects to a bearing. Although SLS nylon (PA12) can provide an excellent bearing surface for slow moving parts (hinges, knobs, etc), at 5000rpm there is a risk of melting. The bearing was an elegant solution.
The staircase includes an upper door to insert the motor. Within the staircase, the motor sits in a motor cage that has vent holes exposed to the airflow for cooling the motor. A wire-conduit is provided to guide the wires from the motor chamber out through the bottom of the fan. The lower door includes a seat for the bearing.
The staircase is raised by three hidden legs that allow for airflow through the array of holes in the base. The perforations, in addition to the upper and lower doors, also allow unsintered nylon powder to escape from the staircase during cleanup after printing.
The print is sized to match the build volume of the Sinterit Lisa, measuring in at 89.9mm x 98.6mm x 115.6mm.
*** POST-PROCESSING ***
The print shop smoothed the part surface using glass bead blasting. At home, I primed the print with Army Painter® black matte primer, and then painted with Games Workshop Citadel Paints using miniatures painting techniques. The mossy grass tufts add texture and color variation for a professional look.
*** ASSEMBLY ***
Insert the motor into the motor chamber with the output shaft facing down. Feed the motor cables through the cable conduit and out the bottom of the fan. Connect the motor to a 9V battery (or any other 6V-9V DC power source). Close the motor chamber with the upper door.
Seat the bearing on the lower door and then fit the door into the lower opening.
Prepare to be winded!
*** LINKS FOR NON-PRINTED PARTS ***
DC Toy/Hobby Motor – 130 Size ($1.95 USD)
MR84z Miniature Bearing (10 for $1)