Bottle Opener

For our first project, the class was tasked with creating a working 2-D bottle opener. My partner, Rachel, and I started by brain storming and drawing a series of possibilities. Both of us were a bit rusty when it came to brainstorming, but we bounced ideas off of one another and drew everything that came to mind. Here are a few of the ideas we came up with.

                   

                                     

After talking through our ideas some more we decided that Bottle Opener #6 or Bottle Opener #9 would be our best choices. We initially decided on #6, but after sleeping on it, we realized that #6 wouldn't be able to work because it didn't have a hold on the top of the bottle cap. In order for the cap to be removed, pressure must be applied to the top of the cap on one side, while pressure is simultaneously applied to the underside of the cap on the other side. So, we brainstormed a little bit more and came up with #9 and #10. After some discussion we come to the conclusion that #9 would work the best.

                                          

A side by side of our two foam core mockups.

Next we worked on drawing our bottle opener on SolidWorks. Even after watching the demo videos solid works was a little finicky and it took as a while to draw our design. It was during our struggle that we made some design changes to our bottle opener. The change didn't affect the physics of the bottle opener, but was an aesthetic change that made building it in SolidWorks easier. After we finally figured everything out, we printed our design on 3/16" Delrin and after some filing, lo and behold, we had our bottle opener.

Our first prototype ended up working pretty well – it was able to successfully remove the cap! When we were filing down the bottle opener, we realized that the underside of the side we were filing down was actually more reliable at removing the cap then on the side we were filing(the side not pictured in the above photo) because the bottle opener was more flush against the cap when we used it that way. This lead us to realize we could build a better version by making the part that was lifting the cap into a curve, so that it would be touching more surface area on the cap and therefore easier to use. To do this we measured the circumference of the cap and calculated the required radius.

On our second prototype, we also redrew most of the part because our first prototype was a little lopsided. After, adding the curve to the bottle opener, we printed a second prototype and once again began filing down. With the first prototype, we didn't have to worry to much about filing unevenly because the flat surface allowed for an even file. With the second one however, the curved surface made it a little more difficult to file evenly and combined with our hastiness, the second prototype didn't work as well as the first. As a result of our uneven filing, our second prototype looked nearly identical to the first. :(

It was also during that time, that we had considered whether or not we needed to have a handle on the bottle opener. When using the prototype to open bottles we applied force on the area nearest the cap and the handle seemed to act only as a resting place for our hands. It didn't make sense to apply the force towards the end of the handle because the cantilever beam equation shows that the further the distance, the more likely the material was to bend and (god forbid) break. For it to work at all, we need our hands to be very close to point of contact with the bottle. By removing the handle, we could save a lot of money in the hypothetical situation that we were to mass produce our bottle opener. It would also be more portable if we removed the handle. In the end, we decided that the handle served a purpose as a counter balance and for user comfort.

On our third and final prototype, we decided to have some fun with our design. After some more brainstorming, we decided to make our bottle opener look like a cat. We added some whiskers and etched on some eyes, the word 'meow,' a collar, and a little bell. It's kind of hard to see the etching in the photo of the bottle opener, but you can see the design more clearly in the screenshot of the part.

                    

This time around we were more careful during the filing process. However, when we went to test our bottle opener, we found that the curve was still to small after we widened it from the second prototype. We came to the realization that although we had made the correct measurements of the cap, we forget to take into consideration that the bottle opener would be used at an angle hence the curve would need to bigger. If we had more time, this would definitely be the first thing we would try to fix. Still, our third prototype turned out significantly better than our first two.

Our bottle opener ended up working because we kept in consideration the cantilever beam equation: deflection = (force*length)/{2*Young's modulus *[base*height^3)/12]}. The amount of force, young's modulus of Delrin, and the height of the prototype are all fixed. The only variables that could be changed are the length and base of the prototype. In order for the part to succeed we need the deflection to be significantly less than the material's max stress: (force * length * height) / {2 * [base*height^3)/12]}. We focused on the length of the part, so we made sure to minimize the distance between the part of contact in order to get our prototype to succeed.

As a I mentioned before, if we had more time, we definitely would have widened the curve to maximize the contact surface area. In order to make the bottle opener more comfortable, we could also file down the sides of the handle as they are a little harsh at the moment. In terms of aesthetic, the engravings on the prototype didn't show up as well as we imagined, so we would probably use a slightly thicker line. Having seen the bottle openers the other groups created, I'm also interested in exploring the pick idea more. If we had more time, I definitely would have pushed for trying to fit on a pick type opener on the end of the handle so that we could have a 2 in 1 bottle opener. Overall, I'm pretty happy with our bottle opener and what we've managed to accomplish!