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The Final Fin:
We pulled three final fins from the mold using a combination of the epoxy core method and the die-cut method.
Final Fin Design
Final Fin Design
The Final Mold:
While running our fabrication analysis tests, we also worked on the tool paths for the final mold.
Final Mold Design
Final Mold Design
Fabrication Analysis II:
Additionally, we did 3 point bending tests on samples of our test fins. We made a custom jig for the Instron machine since our sample pieces were too small for the existing jig.
Our Test Fin Samples
Our Test Fin Samples
Our Custom Instron Jig
Our Custom Instron Jig
3 Point Bending Test
3 Point Bending Test
1C (Sped up).MOV3 Point Bending Test Video
3 Point Bending Test Video
For Sample 1C
From these tests, we were able to generate graphs relating force vs time, as well as force vs displacement. Method 2 was able to withstand the most force, followed closely by Method 3. Method 1 was much weaker than the other methods.
Fabrication Analysis I:
We started to compare the three methods used to make the fins to see which was the best. We contacted local radiologists who agreed to take x-rays of our test fins. From these, we were able to analyze their fiberglass distribution.
Method 1: Epoxy Core
Method 1: Epoxy Core
Method 2: Die-Cut Fiberglass
Method 2: Die-Cut Fiberglass
Method 3: Combination
Method 3: Combination
Fin Fabrication Methods:
Knowing that we could successfully pull fins from two of our molds, we began running tests on three different fabrication methods:
Method 1: Epoxy Core
Method 1: Epoxy Core
Epoxy resin mixed with fiberglass strands
Method 2: Die-Cut
Method 2: Die-Cut
Die-cut sheets of fiberglass layered with resin throughout the entire fin
Method 3: Combination
Method 3: Combination
Combination of Methods 1 and 2. Die-cut fiberglass shell with an epoxy resin + fiberglass strand core
Resin Pours in Test Molds:
We began testing our molds by doing resin pours.
VeroClear Mold Test
VeroClear Mold Test
Unsuccessful: Resin leaked through our PVA layers and bonded the mold halves together. Attempts to separate the halves resulted in breakage.
Silicone Mold Test
Silicone Mold Test
Successful: Was able to produce high-quality fins from the mold, but it required extra prep time to prevent any resin leaks.
Aluminum Mold Test
Aluminum Mold Test
Successful: Was able to produce high-quality fins from the mold.
Running Tests on Release Agents:
To ensure the resin wouldn't bond our molds shut, we had to use release agents. We ran tests on both beeswax and PVA and found that both worked for our purposes.
Beeswax in resin
PVA in resin
Beeswax in resin+fiberglass
PVA in resin+fiberglass
Simplifying the Process:
Our pivot from our original complicated mold led us to this simple test mold. From it, we created both milled aluminum molds and 3D-printed molds.
Test Mold CAD
Test Mold CAD
Aluminum Test Mold
Aluminum Test Mold
VeroClear Test Mold
VeroClear Test Mold
Silicone Test Mold
Silicone Test Mold
Smartfin CAD
Smartfin CAD
The Original CAD
The Original CAD
A complicated starting point. We chose to pivot towards a less complicated test mold in order to do preliminary tests, and to avoid potentially destroying our complex mold at the beginning of our journey.
Our Starting Point
Our Starting Point
We were given a finished Smartfin and tasked with creating a fabrication process for it.
The Smartfin
The Smartfin
The Smartfin's Charger
The Smartfin's Charger
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