2.008 Design & Manufacturing II

50 mass manufactured yoyo's were created for this class.

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2.008 is the second design & manufacturing class at MIT. In contrast to the first, this class places a much larger emphasis on mass production and explores more related concepts and machinery. The main portion of the class revolves around the yoyo, in which teams of 6 design and manufacture 50 yoyos using mass manufacturing methods. This includes mold making using CNC machining, prototyping for function, and then moving to injection molding and thermoforming.

My team made a Lego themed yoyo with the intention of being able to use the yoyo itself as a lego piece. What made our yoyo incredibly unique is the functionality we sought to achieve. While we worked to achieve the simple functional requirements such as the yoyo going down and coming up, we also wanted it to act as a lego piece too. This meant we needed to have a very tight tolerance on our injection molded parts such that they would consistently fit alongside normal lego pieces.

To achieve this, we utilized both analytical and iterative methods. We used previous, similarly shaped yoyos in order to predict shrinkage of our yoyo. From here, we iteratively tested our injection molded parts, retook measureements, and iterated our our mold designs. This process, and most of the overall project is documented in the website above!

• Date: Junior Fall
• Design, Manufacturing

Turner Cube

An aluminum turner cube made to practice CAM and CNC.

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One of my more recent personal projects is the turner cube. I was determined to practice CAM and CNC machining, and I was looking for an object to make that would make use of these skills. Given the repeatable operations of the turner cube, it seemed like the perfect candidate. Beyond practicing my skills, I also really just liked the look of the turner cube, especially as the last face is finished and the inception-like image comes to frution.

With regard to the making process, I started off with a simple CAD that made heavy use of mirrored drawings. I wanted the cube itself to be 2 inches for each side, and so I designed the inner cubes based off this measurement. I was careful not to make the walls of the inner cubes to thin for fear of the delicate supports between the inner and outer cubes breaking in the machining process.

After the design was finished, I began to prepare my stock. I repurposed some aluminum 7075 from a different project for the turner cube. Given the stock was already faced to 2" in thickness, I cut out a the other two dimensions to approximately 2.25" on a vertical bandsaw, allowing me stock to face off. I then used a mill to face off the extra stock and remove the bandsaw marks; I used the already faced sides for holding in the vice to ensure that my stock would aligned correctly and so I would end up with a square cross-section instead of a rhombus. I then faced the 2 sides that had been in contact with the bandsaw down, up until I had a 2" cube.

For my CAM, I opted to use a 1/2" bull-nose carbide end mill for the rough cuts and then finishing with a HSS flat end mill for removing the radii left by the bull-nose. I also used a HSS drill for the inner most hole. Given that I would only need to create this inner through hole on 3 of the 6 faces, I created two CAMS, one with the drill operation and one without. I was sure to use as short a HSS tool as possible so as to mitigate as much chatter as possible. Ideally, I would have liked a 1/2" flat carbide end mill, but did not have access to such a tool. My CAM is simple and consists of a roughing operation by the carbide tool, and then faces the sides and removes the fillets with the HSS tool. The operation takes about 6 minutes.

For the machining process itself, I used a mill position work stop so I would only have to zero my piece once as I rotated it. From here, I simply zeroed my pieces, ran a dry run in air, and then ran the appropriate CAMs for each side.

I finished the project by wiping off the pieces as best I could and then using a hypersonic cleaner to remove any other oil and chips.

• Date: Junior Fall
• Design, Manufacturing

Upright

Manufactured critical suspension component

During my Junior Fall, I was tasked with manufacturng the upright as part of the Solar Car suspension system. I was really excited to be working on the upright specifically as it had 3 different interfaces with other parts; it was also an oppurtunity to learn and use the HASS machine.

The first thing I did when assigned the project was to order material stock as that had the longest lead time. I measured length, width, and height and rounded each measurment up to the nearest 1/2 inch. This was to allow ordering standard dimensioned parts and also to allow me to get cleaner finishes when removing the extra stock.

Next, I adjusted the CAD for manufacturability. This encompassed changing fillets to be standard (and feasible) radii as well as other small changes necessary to minimize machine and tool changes. These changes continued as I began the CAM process.

I tackled the manufacturing process in a very high level to low level process. After the CAD changes were largely finished, I began to plan the actual manufacturing steps themselves, including the order of manufacturing processes themselves. With the CAM, I used the standard tool library to first test the manufacturability of the part in its current state. I then experimented with different CAM features and run time, aiming to decrease machine time as much as possible while not sacrificing quality of the part, especially at contact surfaces. After working with the head of the machine shop, I was able to decrease machine time from 8 hours to 1 hour and 15 minutes; this was done by utilizing a bull nose 1/2 inch carbide tool, which dramatically increased my MRR. Otherwise strides were made by using more optimized CAM operations that were possible because of the bull nose (vs a flat nose).

At this point, the first attempt was made at actually manufacturing the upright as a test run. After paying special attention to surface finishes and important dimensions and making necessary adjustments to the CAM, 2 more uprights were fully manufactured and installed into the car.

• Date: Junior Fall
• Solar Car

Glass Bear

A fun project made as a gift for a friend!

The glass bear was a fun personal project I got to work on as I learned glass working. The process consisted of creating a ball of softened glass using a bunsen burner for heat, pressing the ball into a bear mold, removing the bear, and finishing off the still softened piece with any extra colors or sparkles (such as what I did!)

• Date: Sophomore Spring
• Manufacturing

Pickup Truck

A pickup truck made from multiple materials to practice manual, conversational, and CNC machining.

Going into my sophomore spring, I really wanted to develop my machining skills, namely beyond manual capability. I therefore enrolled in a 3-day project class that employed a combination of machining "theory" and practice. In the classroom, we learned about the microscopic interactions that differentiated climb and conventional cutting, why and how tools break, possible causes for unexpected high error, and a multitude of other topics. In the machine shop, we used manual, converational, and CNC machining to create the pickup truck pictured above.

With regards to process, we were given a drawing from which to machine manually the stock. This was largely in the realm of prepping the stock for further machining. Conversational machining was used to create the pockets on the bed and top of the truck as well as the front hood. CNC machining was lastly used to create the wheel wells and windows. The delrin wheels, the aluminum wheel axles, and the brass headlights were all manually turned. While the wheels and axles had relatively large tolerances, the headlights were machined for a press fit and thus had a much tighter tolerance.

• Date: Sophomore Spring
• Design, Manufacturing

Lower A-Arm

Redesign and manufacturing of a critical suspension component

The lower a-arm was my first project on the solar car team. I was tasked with redesigning the lower a-arm as its predecessor consisted of welded together tubes. This led to inconsistent manufacturing methods as well as limitations of strength. Using pre-existing contact points from the welded version, I designed a machinable lower a-arm. I verified my designs using Solidworks FEA. I then manufactured 4 a-arms out of 4140 steel using the water jet and mill.

• Date: Freshman Fall
• Analysis, Design, Manufacturing

2.007 Competition Robot

Designed mechanisms of a robot for a class-wide competition

This competition robot was designed as part of our Design and Manufacturing I class. Mine employed a winch to control a pivotting scooper in order to collect rocks.

• Date: Sophomore Spring
• Analysis, Design, Manufacturing

BattleBoats

A product developed in the 2.00B: Toy Product Design class

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A project I worked on during my Freshman Spring was in the my Toy Product Design class. The class consisted of teams of 6 working together to create a toy that is attractive to children within an age range. In this class, the entire design process is touched upon, from brainstorming and ideation to mock ups and user testing, to a final prototype and presentation.

The toy my team created is BattleBoats. BattleBoats is a product in which the user has an RC boat that can also shoot at other boats, but also be shot at. In the game, two players will try to "sink" the opposing players boat. The indicator for a sunk boat is how much water has accumulated on one's deck. The main modules for the product consist of the RC controls, the water pump and cannon, and the health subsystem.

The controls module was based around learning from what had been done before. We did research into different forms of communication such as RC and looked into potential problems we might face. After deciding to use RC, we decided the amount of controls we would need as that would correspond to the # of channels our controller would have to support. Given a forward/backward control, a rudder control, and water cannon control, only 3 channels were needed. With our overall design requirements set, we purchased a RC controller and reciever set. For the motors and rudder, we reused parts from an existing RC boat. This reuse allowed us to save time not having to spec those components.

The water cannon system consists of the water pump and a tube leading to a nozzle. The pump draws water from the belly of the boat itself. With this system, we experimented with different nozzle types so as simulated different game strategies. For example, a very small nozzle would allow for long-range water shooting, while nozzle with a large hole would flood a boat at close range.

Lastly, the health system functional requirement was to measure the a health game-state of the boat and indicate to the user their health in some form. We began with figuring out the best way to measure health and decided that an reservoir would be made on the deck of the boat; the rest of the deck is angled towards the reservoir such that any water splashed onto the deck will flow to the reservoir. Next, we wanted to find the most reliable way to measure the water level. Using market water sensors lead to issues of inaccurate readings from the boat rocking. In the end, we used open circuits at 3 discrete heights in the reservoir. As the water flowed in, the minerals in the water would complete the circuit at each height. We also placed all positive terminals on the same side. In this configuration, if the boat were to rock, the water would connect two negative (or positive) terminals and thus the logic board would not see a new circuit connected. As the three discrete water levels were reached, different colored LEDs would light behind the portholes, indicating to the user their health.

• Date: Freshman Spring
• Design, Manufacturing

Thermal Case Study 1: Heated Cylinder

Comparing thermal response of a cylinder with and without insulative sleeve

• Date: Junior Fall
• Analysis

Thermal Case Study 2: Skillet Handle

Looked into handle temperature distribution of hot cast iron skillet and potential design fixes

• Date: Junior Fall
• Analysis

Thermal Case Study 3: Potato

Analyzed the effect aluminum foil has when baking a potato and in keeping the potato hot

• Date: Junior Fall
• Analysis