Mini Projects: Engineering
Various projects from classwork
Design for Manufacturing II, Spring 2018
Solar Sytem Yo-yo
Yoyo designed for rapid manufacturing
Designed and manufactured 50 identical yoyos using injection molding and thermoforming methods in a group of 6. Ensuring we hit our goal at the end of the semester meant we kept a tight control over both design and process parameters at the manufacturing stage.
Final yo-yos. Outer space made by mixing auto body flakes into black plastic during molding.
1 snap fit holds all together with the rest of the components loosely stacked to increase tolerance windows as well as save time in assembly. Drafts and components of even thicknesses ensure plastic flow in IM and minimize sink risks.
In manufacturing, optimizing cooling times to reduce manufacturing time. 1 snap fit meant we only had to have longer cooling times in 2 components for increased dimensional accuracy. For setting injection pressure and cooling time we utilized run charts to track critical measurements of each component.
Field Work for D-Lab: Development , Winter 2018
Co-creation: Rocket Stove
Rocket stove designed for use in D'Kar, Botswana
This project is a continuation of the class D-Lab: Development. The class focused on evaluating products for development on the market, in terms of technology, price and ethnographic fit to different communities. I got to learn about the products that enhance an experience like all the different kinds of human waste management solutions, or introduced a culture change and impacted life.
In the field work portion I observed how a good design can introduce a culture change to impact life in a large scale, in a healthy way. For two weeks, I collaborated with a community member in D’Kar Village to develop rocket stoves.
Testing prototype stove with Mathambo, community partner in D'Kar
Top view of the rocket stove. We constructed an adjustable "pot skirt' to increase the heat transfer to the pot
While rocket stoves are a common developing world project because they are easy to manufacture and have higher efficiency and health benefits, this community previously had shown no interest. We started with technical tweaks, by changing the chimney height to optimize draft and reduce cooking time, but this would not have mattered if we did not work to fit the stove into their life. Cooking around open fire was a daily ritual they enjoyed sharing with their family. Living with locals who complained about the strain on traditional firewood, I proposed to reduce the stove’s size to use small twigs instead. After this, an excited user base emerged because they could still have traditional open fire dinners with the whole family, but when they wanted to cook individual meals, rocket stoves were more practical.
2.70: Fundamentals of Precision Product Design Spring 2019
Fundamentals
Toys to Demonstrate Principals of Precision Machine Design
In a team of two, designed gadgets that demonstrate the assigned set of fundamental principles of machine design. Brought every deliverable through the design cycle. From principles to concepts that demonstrate them, first order analysis, design, manufacturing and testing and closing the loop to reflect on the design. Produced 3 copies of every toy to demonstrate repeatable design for manufacturing.
Micrometer body built for assignment 5: Parallel axis theorem and structural loops. The I beam shaped body increases the stiffness of the tool and keeps measurements accurate.
Principles demonstrated:
1: Preload & Self-correcting
2: Saint-Venant’s Principle, Golden Rectangle & Stability
3: Abbe’s Principle, Accuracy, Repeatability, Resolution
Sensitive Directions & Reference Features
4: Centers of Action, Symmetry, Maxwell & Reciprocity
5: Parallel Axis Theorem & Structural Loops
6: Exact Constraint Design & Elastically Averaged Design
Assignment 1: The car has butterfly nuts that load the washers (black) when turned. Loose washers cause a bumpy and loud ride while preloaded washers result in a smooth ride.
A flexure to accurately predict the jamming force for assigment 2: Saint-Venant’s Principle, Golden Rectangle & Stability. As the block is pulled at an angle, the flexure block moves parallel to the other side, eliminating cosine errors in measuring displacement. Jamming load is measured with Hooke's law, after determining the spring constant of the flexure and measuring
MIT FSAE
Fall 2017 & Spring 2018
Fall 2017 & Spring 2018
WING MOUNTING
Over previous years, the wing mounting systems were engineered to achieve optimal force distribution, but the usability was neglected. Along with the usual structural support for the wings, I aimed to make the wing mounting system into a platform where the aero team could improve the lift and drag properties of the overall car experimentally with repeatable, incremental position adjustment.
This is the first year the wing mounting design is kept the same because the time saved during competition was a valuable trade off, and the aero team is able to carry their engineering forward by exploring full car aerodynamics with the new wing mounting design.
Detail. Wing mounting as installed on the car.
Synthesized "ratcheted slots" for incremental adjustment of height and pitch of the front wing. Front wing mounting structure highlighted on the CAD.
Bracket on the rear wing. Height of wing is changed by sliding the rod end vertically and the distance of wing to chassis by sliding it along the slot.
I restructured the mounting bar geometry to decouple the important directions of wing adjustment so each of them could be changed independently and ensured repeatability of position changes via ratcheted slots that only move in ⅛ inch increments. This design enabled the aero team to gain control over drag and downforce, the two big parameters of vehicle aerodynamics, even though the new bar geometry resulted in a less optimal force distribution.
Fall 2018 & Spring 2019
Water Cooling
Battery & Cooling Teams: Cold plate design for the battery & motor controllers
As the battery cooling lead, I took on introducing a liquid cooling system to our battery. This large scope project required a very flexible understanding of the design process. I had to rely on my skill to seek information from many sources and synthesize these to create an adept solution.
I committed to making use of the diverse environment of mechanical, electrical, manufacturing and packaging engineers to grow our once independent designs together. By collaborating closely with the packaging lead to place principles of heat transfer in the core of our battery architecture, we achieved unparalleled energy density and thermal regulation in Formula SAE.
Simulated water flow in possible cold plates in SW CFD
Test module design by Ethan Perrin. The cooling channels are shown in green.
Constructed a test bench to verify simulation results and designs. When a radiator or cold plate is inserted between the quick disconnects, water circulates in the bench. Pressure gauges and thermocouples are inserted to the inlet and outlet of the testing block to measure the two properties across the cold plate.
Here I interfaced with a lot of people with different specialties to find the correct sensors, tube fittings and all the other components I used to build the test setups.
Measuring temperature and pressure drop across a radiator on the test bench.
Example cold plates. Two sides screw in together and seal with o-rings. They connect to the cooling loop via quick disconnects.
With the learnings from the battery cold plate design, constructed cold plated for the front motor controllers. Cold plates, highlighted in blue, sit under the motor controllers.
Even though I gained a lot of domain knowledge with this project, my biggest takeaway is the importance of staying curious. Continuously looking for better information and learning how to communicate with people of different backgrounds enabled me to take on this project I could not have worked on within the limits of my initial knowledge.
