Flywheel Fabrication

In this project, I fabricated an air powered flywheel utlizing various machine shop tools including milling, casting, injection molding, plasma cutting, composite layup, and 4 axis CNC machining.

CAD Model

I first started off by creating a CAD assembly in Nx. The device works by blowing air into the nozzle (grey) which travels through holes in the backbone that drive a piston and crank shaft that ulimately spins the flywheel.

Kinimatic and Dynamic Simulation

To test if the structure would travel across a table top while spinning/vibrating, I performed a kinematic and dynamic motion analysis.

The coefficient of speed fluctuation is 0.022 or 2.2

Pressure = 62kPa

Radius = 4.7625mm

Area = 3.14*Radius^2

= 71.26mm^2

CS = (𝜔2 − 𝜔1)/𝜔1

= (-52.6 + 53.8)/-53.8

= 0.022

Force = Pressure*Area

= 4.418 N

IYY= 326.82998 kg·mm²

Mass = 0.6617 kg

Weight = 0.6617 * 9.81 = 6.49 N

Lateral Force = 6.49 * 0.1 = 0.649 N

Inertial Load = 0.723 N

It was determined the Lateral force generated by system imbalance at 500RPM is 0.723 N. Therefore, this force can cause the system to slide on its supports.

Flywheel Mold Base

The mold for the flywheel itself was created in Nx utilizing the CAM function by subtracting the flywheel from the base, creating tool path, post processing the tool path, and operation sheets.
The program data generated was used to create the mold base in a CNC machine.

Casting

The flywheel was casted with pewter. The edges of the mold were tapered to allow easier removal of the casted piece from the mold.

4 Axis CNC Machining

Utilizing Nx, I created the tools, tool paths, and G code for the CNC machine to run. The part created was the backbone of the flywheel assembly. It required spot drilling, drilling, milling, and tapping. The images below show the backbone (in yellow) fixed to a Haas CNC machine.

Composite Layup of Propeller

To create the propeller for the flywheel assembly, I layedup a multi-layer carbon fiber composite pre-preg on a mold.

Milling

I manually milled the crankshaft, piston, and cylinder. The tightest tolerance of position with my machining ability is +/- 0.002. I was able to control the movement of the mill in most cases by +/- 0.001, however there were some cases where the closest I could get to the true position was +/- 0.002.

Plasma Cutting

The base of the assembly was fabricated through plasma cutting sheet metal. The edges were then folded.

Injection Molding

The "feet" of the stand for the assembly was created through injection molding plastic