Windlass Planning

Tuesday night Anya and I decided to start designing our windlass. We began by sketching parts designs that we thought could work under the parameters. There was the spool, the stand and base, the handle/lever, and the connections. 
Spool: It needed to be strong since it would be carrying most of the weight from the bottle. We didn't want all the string to wrap over its self too and create a weak point or to spread out too far. One design we came up with was an attempt to spiral the string across the spool but that would have require us carving into the delrin rod. We thought another way to achieve the spiraling string would be to cut a wavy a pattern out of delrin to guide the string across the spool. A second idea was to have two rods spaced apart so that each rotation of the handle would pull up more string. This would also distribute the weight across two rods. We played around with having three rods and having supports in the middle. In the end, we trusted the strength of a two pronged delrin spool which would also save us material. Our final spool design has a hole for the string and a notch to keep the string from going to the weak spot of the center of the spool. 
We also played around with some other ideas for fun such as one that we found on the internet that has two rods, one that fits in the other and a pulley. All the sting is initially on the wide rod, through the pulley (which attached to the bottle) and then to the small rod. The crank turns the small rod transferring the rope to the that rod and would give us double the pulling power. We though about ways to minimize material. Since we were only rotating the string on the side instead of the center, the would right side of of the spool was useless. We tried cutting it short by making it sloped or trapezoidal. Also, since the goal was to get the bottle 10 cm above the table  Anya had the idea of a V shaped spool that would lift the bottle all the way up in just one crank. 


Crank/Handle: To power the windlass and get the string up, we needed a crank. This was a pretty simple design. At first we toyed with the idea of gears to get more string up per wind, or ratcheting so that the crack wouldn't unwind on us but it wasn't essential to the challenge so we left it alone. If we did have gears, the handle was going to be on the outside of the circle to increase our advantage. To simplify things, the handle and the spool ended up being one piece with the handle centered. 

Base/Stand: We decided to go for a pyramidal shape for the base. We initially had one piece that went parallel to the table but then as support we added a perpendicular piece. These two pieces fit together through notches. We played around with having the second peice slant more outwards, or having one leg. In the end we finalized it to have to equal length legs so that the base of the support stand would look like a square. The parallel piece has a hole in it to hold the spool.
Connections: We needed pieces to hold everything together. The connection between the two stand pieces would be a simple notch that they would fit into. The other connection we needed to worry about was the stand and the spool. The spool would be cut out of rectangular delrin and we needed it to move in a circle. We designed an open bushing that was a circle with a notch that would fit on the spool. This washer-thing would fit in the circular hole of the stand and rotate in there. We had assumed that it would be a tight and fit and be held in fine. 

Final Design

All the piece we initially designed
Notes from Class (at top of page):
- two spool pieces layered on top of each other for strength
-triangular spool
- more notches to guide string
-connection between washer piece and stand - w/piano wire/heat stake?

some modifications

3D Printer Pen

This is a fun article I found about a 3D Printer Pen

Plastic Extruding Pen 3-D Prints Whatever You Draw






The 3Doodler (not to brag or anything but I've actually been 4doodled before) is a pen that 3-D prints whatever you draw. Think of it as a hot-glue gun except with instantly-hardening plastic. You can dry with the plastic on a flat surface and then peel it off for 2-D objects, or draw with the pen in 3-D to create free-standing ones. The 3Doodler is currently a Kickstater project but has already reached over 25x their goal. You can still preorder a pen and two bags of plastic though for $75. They ship in November. Me? I never ship, which is why my eBay ranking is so low. I hate the post office. If I had to choose between going to the post office or the doctor's office I think I'd have a nervous breakdown and puke.

Hit the jump for a bunch of examples of creations and their Kickstarter video.

Fastening and Attaching Delrin

Heat Staking
Heat staking is when a peg from one piece fits into a hole from another piece the protruding peg is melted and fuses on to the other piece. This creates a pretty strong hold between the two pieces. The method generally limits the type of joint you create unless you get creative. It seems sturdiest with a square peg and hole at a right angle, though you could try a rod and melt enough so that that it doesn't fall into the hole.

Piano Wire

Two pieces of Delrin can be attached by drilling a hole through them and stringing through piano wire. We have the option of thicker or thinner wire and if we want a pressed fit or a running fit. The running fit has some wiggle room and you can rotate the pieces around it. The pressed fit connects the two pieces and there is no movement between them or the wire. This works for keeping two pieces together along a vertical line.


Notches and Pegs
For notches and pegs, I designed on Solidworks my own notches and pegs. The thickness of the Delrin was 49.6 mm so the center notch on the board was that thickness. The notches  above and below that notch were .1 mm larger or smaller than the ones next to it. The pegs were made with exact dimensions of the center notches. When I put the peg into the notches, I found that the pegs fit into the the center notch quite tightly. It fit into the wider notches with some wiggle room but not at all into the smallest holes. The notch .1 mm smaller fit very tightly and would not budge. Again we are limited to 90 degree joints.

Bushings
Essentially a tube that fits over a rod. Bushings can be difficult to make since the inner diameter must be the perfect diameter for whatever purpose you need them for (tight fit or loose fit). Bushings can be used as spacers between two pieces or they can be used to prevent  the rod from sliding around in wholes.
Loose Fit: The rod is able to rotate in the bushings
Tight Fit: The bushing rotates with the rod

Bottle Opener

My partner Alisha and I began by thinking of bottle openers that we had seen and how they worked. The opener could either slide over the cap, attaching to it then pulling it off or it could slide under the cap then pop it off. We decided that out approach would be to pop the cap off from the underside. The basic design of was a 'tooth' to go under the cap and a part that goes on the other side of the bottle (we later discovered that we wanted this second piece to be on the cap- we would get better leverage that way). About half of our designs followed this formula with modifications - number of teeth, placement of teeth, would the handle allow us to push up from the bellow or would be pull from above. One challenge with these designs is that we needed thick Delrin for the structure to be strong, but we needed a thin tooth to fit under the can. This meant that we would have to shave the material down after laser cutting. 


We chose our three final design after looking at which we though would have the best leverage. After making  a Pugh Chart, we decided that the most important criteria would be effort. We settled on the 'Vampire' design, finalizing how it would fit on the cap, the angles, and the shape of the tooth after filing it down. We realized that two teeth would not give us the the leverage we needed and that the end of the opener had to be on the cap. We revised this design to one centered, wide tooth, a wider handle, and having the end of the opener be midway through the cap. We also added a thumb whole which we hoped would create better leverage by allowing us to use our whole arm instead of just the wrist and palm.



Prototype 1
Photo stolen from Alisha's blog 

After we finalized our design, we began working on SolidWorks. I have worked with a program similar to SolidWorks before so this part was fun. We measured our prototype and the bottle for our final sketch to make sure the dimensions were right. Once the final sketch was ready, we laser cut the bottle opener on the second thickest piece of Delrin. When we initially tested it, I had a feeling it wasn't going to work. The initial design required a thin, filed edge on the tooth. Filing the Delrin took longer than we anticipated. We kept testing the design to no avail. Terrified that we had failed, Alisha and I began coming up with new designs. We thought about how we could get the thickness to work on our side. Doing this would reqtuire looking at the material from a different perspective. We came up with a design that looked quite similar to the bottle opener used in the that SolidWorks video from class. The tip was getting cracked from failed attempts. In the end, we shaved the lip of the the tooth down enough that it finally opened the bottle. We had to adjust the way we held the bottle opener to get a good grip and good leverage.

If I were to do this project over again, I would have designed the opener from the side rather than the front. That way we could use the thickness to out advantage and have a sharp tip without any extra work. 

Fun Bottle Openers

You know how when you are studying something in class and all of a sudden you it what you are learning in the real world?
Well these pictures just found me, I never searched for them

Star Trek Bottle Openers

Bullet Bottle Opener

TV Remote Bottle Opener

My Goals

I have been interested in engineering for a while now. I have taken engineering classes my junior and senior year of high school and really enjoyed it. I think the only reason I didn't go to an engineering school was that I was scared that it would take over my life and I wouldn't be able to explore other things that interested me.
My goals for this semester is to expand my knowledge of the different branches of engineering and to see if there is any other branch besides civil that could complement my intended major of architecture. I want to learn more about the opportunities at Olin that I can take advantage of. I also want to get more comfortable with the computer programs used in engineering - I am more of a pen and paper sort of person. Also, I want to have fun and push my self to do my best.