Bottle Opener

Our mission was to design and create a 2D bottle opener out of Delrin, a plastic, that would be cut out with a laser cutter. This was our final result:

The bottle opener worked! My partner, Julie, and I were thrilled that our bottle opener was successful. 

Now how did we go about creating this, you ask? 

We started off by brainstorming ideas for the project. Some ideas were reasonable, while others made little sense. We knew that we wanted one part of the bottle opener to hook under the bottle cap and for there to be a handle to act as a lever.

We gathered the ten sketches that made the most sense and compiled them onto one sheet. It was actually a bit difficult to create ten unique ideas for the bottle opener, as when we went through the sketches, we realized that many of the sketches were quite similar. The 2D aspect of the project also eliminated a few of our brainstormed ideas. 

We then contemplated which one(s) would be most likely to work and be least likely to break. 

The main idea behind a bottle opener is a lever. In order for a lever to work, you need one point that does not move -- the pivot -- and one point where the force, or effort, is exerted, as shown below. Our sketches all generally followed this principle. The handle of the bottle opener is where the force is exerted, while the bracing point, like the rounded head of sketch 10, is the fulcrum. The hook or flat edge used to attach to the underside of the bottle cap is the load.

We found that sketches 5, 6, 7, and 9 from above did not have a clear fulcrum and would not be able to brace on to the cap for the bottle to open. 

Sketches 1, 2, 3 and  4 were all similar and we felt that the bottom edge of the opening, either a semi-circle or upside-down pear shape, would not latch on to the bottom of the cap as well as a hook would. Therefore the load would not be secure. Also, the long horizontal handle may be more prone to breaking or bending compared to a vertical handle. 

According to the principle of cantilevers, the goal is have the least amount of deflection in the device. In order to have that, the length of the lever must not be too long, following the equation 

deflection = FL^3/EI. 

Since we cannot change the force (F) required to open a bottle, nor can we change Young's modules (E), it was important for us to consider the length of the device.

In the end, we decided to use the last design, number 10. Sketch 8 had a flat head while 10 had a rounded head, which would serve as the better pivoting point. 

By pulling up the bottle opener (with the opener in the right hand), the handle would provide a counter-clockwise direction torque of the object. The hook, which acts as the load, would lift up the cap by providing a counter-clockwise torque while the rounded head would act as the fulcrum to secure one end of the lever at the top of the cap.  



Torque is the force needed to rotate an object and is determined by the force exerted and the distance at the which the force is applied from the pivot point. The handle is farther away from the fulcrum than the hook and therefore can apply a larger torque to the bottle opener than the hook while using the same amount of force. 

We drew several versions of the design, each version having varying lengths between the head and the hook and slightly different hook shapes. The final version, number 5, incorporated a shorter distance between the head and the hook and a wider hook to prevent the risk of the hook breaking.

Now that we had a design, the next step was to modify the design to fit the specifications of the Sprite bottle that we were working with. By measuring the bottle cap dimensions, we obtained approximate measurements for the bottle opener.

We proceeded to cut the design onto foam core.

We found that the distance between the head and the hook was too large to fit on the bottle cap. As result, we shortened the length and cut another foam core model.

We tried it on the bottle again, and this time it fit better!
We were ready to move on to Solidworks.

After a lot of frustration and confusion, and many re-dos, we finally had a 2D design, which we then extruded. We had quite a bit of trouble with the extruding, but Larry was a huge help to us.

I thought that the Solidworks sketching would the most difficult part, and that the laser cutting would a piece of cake.
Wrong.

Julie and I were the first pair to attempt to use the laser cutter, and thus encountered many, many problems.
We first went back and forth between the two computers, converting the Solidworks file to PDF, DXF, and other file types in an attempt to find a file that the program would accept. DXF worked for us in the end.

The second difficulty was found when setting up the laser cutter job order. Sometimes the sketch would not be shown in red, although we had just adjusted the color. Also, many times the sketch preview would not always show up.
Once we finally had the settings correct, and everything was showing up on the program as it was supposed to, we sent the job to the laser cutter. It took several cuts, and several adjustments to the velocity and power, for the laser to cut through the delrine.

And, we had our bottle opener! It successfully opened the bottle on our first try. All of the frustration of struggling through the Solidworks design and the laser cutter settings made the final result that much more rewarding.

We used the opener several times and it did not seem to chip at the hook. However, one correction I would make if we were to make another bottle opener would be to make the handle a bit wider for easier grip. Overall, I enjoyed this process and found the project to be very interesting. Using Solidworks and the laser cutting was definitely a learning experience, and I look forward to using the them for the well windlass!