Main Puncture Unit

The main puncture assembly cradles cans on a spring-supported bed. A double-cylinder pneumatic piston compresses the bed against a drill bit, puncturing the can. Fluids run down the drill bit and drain into a 13-gal drum.

Loading/Unloading

Long pneumatic pistons push pairs of cans into the puncture unit. To ensure cans aren’t pushed out the other end, a smaller piston swings an arm to pinch the cans into position. After the cycle is complete, the arm swings out and the cans are pushed through the system into a disposal bin

Control Panel

The control panel ensures pistons fire as instructed in our code.

Hill Air Force Base (HAFB) produces 40,000 waste aerosol cans per year. To properly dispose of the cans, technicians must puncture, drain, and recycle each can. To reduce labor time and personnel exposure, we were tasked with developing a mechanical unit that would:

1. Minimize airborne contaminates
2. Operate at speeds comparable to technician
3. Allow the operator to change programmable settings
4. Work with various can sizes
5. Operate with consistency and minimal human interaction
6. Fit in a 10x10 ft space

Performance Review:

Minimize Airborne Contaminates [Yes]
After cycling cans through our system, we attempted to feel, smell, or visually identify aerosol escape. No aerosols were detected.

Operate at Speeds Comparable to Technician [Unmet at current condition]
Due to time constraints, our stopping assembly didn’t work as expected. At its current state, our machine cannot cycle cans at speeds comparable to a tech (20 cans per minute).

Allow the operator to change programmable settings [Yes]
A visual inspection of the code yields easy-toread structure and clearly labeled variables. Further, our sponsor at HAFB can verify how long it takes to change the code.

Work with various can sizes [Yes]
Our double puncture unit passed a fit check for the largest cans (12”) found at HAFB. Further, the loading piston is long enough to push the smallest cans (6”) out the back. Operate with Consistency and Minimal

Human Interaction [TBD]
Due to time constraints, we only ran a few cycles through our machine. Therefore, actual reliability is left to be determined.

Fit in 10x10 ft space [Yes]
Our entire system is mounted on a small, 2- shelf mobile cart. Thus, we met this requirement.

Conclusion

Currently, our unit meets 3 of the 5 customer constraints. However, our unit can meet all requirements with minor changes and more testing.

Lessons Learned

We learned that part lead times can constrain a project’s timeline significantly. Further, we learned that communication and timely decisions early on make the designand- build process more efficient.

Future Work

We recommend that Hill Air Force Base focus on the stopping assembly. Either,

1. Remove the stopping assembly and rely solely on pushing piston placement
2. Install pistons at the same height as the unit on a separate stand. Use these pistons to trap the can inside the unit.