Going into my Freshman year, I knew I wanted to be apart of Engineers Without Borders, with both my passions for service and also love for international travel and humanitarian aid. I searched and searched for EWB at Club Fair, happened to be free on my Tuesday nights, and joined the Malawi Chapter (meetings always SEC Anderson 208).
With this, after pouring our heart and souls into finishing the Implementation Plan, calling with the community monthly, emailing and prodding at contractors with budgets, checking up flights and understanding visas, the hours of work came to a peak with our August 2023 Implementation trip with a team of 6.
Below is a short compilation of the five days we spent in the community, with interviews, soccer games, painting of periodic tables and so much more:
Here is a look into the student’s water access before the tap stands, but after our chapter’s 2018 borehole.
I was lucky enough to be able to continue what we started and brought a team back August 2024 for a Monitor & Evaluation and Assessment Trip where we were able to see the impact of our project (both expected and unexpected). We conducted repairs on areas broken because of misuse and bad design and talked with heads of school to talk about learning materials needed for maintenance and repairs. Assessing 3 other communities was also eye opening as it gave me a larger context of what life looks like in different communities within Malawi. (edited Sept 2024)
Greenhouse Grand Opening with Project Leads (me & Max), presidents (Julia & Sam), and many tech leads!
At the start of 2023, the Malawi Chapter of Tufts Engineers Without Borders had a happy issue of too many members, but not enough to do. Our project was very internationally focused with a remote implementation. With a project starting in 2017, our clean water-access project has a long history with lots of background knowledge that was hard to explain to new members in a digestible way. Because of this, there was not enough hands-on engineering in our weekly meetings. It was also hard to connect members with our Malawi project and culture.
Furthermore, we wanted to have an on campus space to connect with the greater Tufts community and show off our excitement for EWB. Aligning with the values of Engineers Without Borders, our chapter wanted to focus on a locally based, but internationally focused sustainable, environmentally friendly project.
How can we bring our excitement for hands-on engineering, team based projects, international awareness, while making our campus more green and community focused?
With this project, we will be able to learn how to timeline an engineering project from start to finish, mobilize our tech groups to create something they can see, build, and take ownership for and also teach by doing the different aspects of an engineering project. Our chapter also could take methods of fabrication, design, and prototyping from the classroom into something we could work on and build in our weekly meetings. Skills such as CAD, strength simulations, laser cutting, 3D printing, community surveying, project management, and more could be applied throughout the journey of this project. All these skills learned through Project Greenhouse are the same skills needed for our Malawi Project; Showing and learning it through a smaller and local project, rather than just explaining it, was very beneficial in teaching what an Engineers Without Borders projects are all about.
When figuring out what to mold, our group looked into multiple options, from molding a finger, to a case for the button, to a handle bar for the walker we were rough prototyping.
We figured we would try something simple to start, with the handle of the walker, first designing it on a mop handle, then a stand alone clay model with ridges for finger/hand placement.
Making the carrying device
To prep for the molding process, a box was created and water proofed, with some styrofoam padding to reduce the width of the container and the amount of molding material needed.
Pouring the mold
We used the SmoothCast 305 with Mixed Part A and B in a 1:1 volume ratio. The container used to mix the two parts was a little too small, so the amount of SmoothCast 305 used was a little too little. Our process was pouring some Mold material into the container, and then placing the clay model on top and pouring in the rest of the material from the corner.
Removing the mold
After sitting in the cabinet overnight, the mold was taken out of the container and the clay model was removed from the inside of the mold. Mold Release Spray was sprayed in the interior surfaces and Smooth-Sil 940 was prepared for the casting. The mold had slight imperfections such as a hole at the bottom where the clay model and sunk to the bottom and touched the container instead of staying afloat in the molding material.
Pouring the object
When pouring the cast into the mold, careful considerations of pouring through the side on an angle was taken to minimize bubbles. Last minute, we tried to add a hole on the top so the handle could be attached to a pole, but this was done too late so we decided to do this two part type molding next time.
Removing the object
The cast solidified pretty soon after (and heated up pretty warmly) but we decided timing wise it would be easier and safer to let it sit. When removing the cast from the mold, we had to cut it a part a bit and twist it on the way out. There was also left over residue of the clay that left a brown and bumpy finish to the casted item.
Post Processingand Final Product
Because of the unappealing look of the handle, we decided to paint it a more health inspiring color, light blue!
Part Two: The Two Part Mold
Making the design
When trying to figure out what to cast for the two part mold, we wanted to try something with more complex. With the holidays coming up, and the temperature dropping, a Christmas/evergreen tree seemed right so we 3D printed one to mold.
Constructing the first side
When preparing the first side of this mold, clay was used to block off one side of the tree with dents that are used as the release pins for the two part mold.
Pouring the mold
The same mold materials as before was used. This time, the amount measured was enough to fill the cavity and object, which was good and made it so there would be no holes at the top or bottom.
Removing the mold
There was a little bit of spillage but a pretty clean mold.
Constructing/Pouring the second side
After placing the first part of the mold and tree back into the container, the second part of the mold was poured in.
Pouring the object
After waiting for the mold to set, it was then taped together and SmoothCast 305 was measured and poured in.
Removing the object
There was slight extra material at the top and the tip of the tree was lost.
Trial Two
We wanted to try a different material and try to make a cleaner cast. We picked Perfect Plaster after looking at another groups casting project.
Pouring the object
Removing the object
There was not enough casting material to fully fill the cavity so the top part was not filled completely. There was also tons of spillage from the sides, possibly from the roughness of how we handled the mold and cast together.
Two Part Mold Final Products
As you can see, the first trial gave a more full object, with more extra artifacts on the sides of the tree. With the second plaster mold, there was more detail and less external artifacts, however the measurement was not done properly so the whole shape was not able to be casted. For the future, proper volume measurement should be taken and kept consistent, as well as better and stronger hold of the two pieces of the mold.
I explored the ideas of combining different aspects of simple examples (ex. buttons, lights, sound) to make a little piano. I am a musician since birth, basically, and know how to play 7+ instruments, so of course, I had to make a little circuit one! This was also helpful because my group project will use a button to lock breaks so it would be easier to use. I used the button sensors, a passive buzzer, and lights to provide multi-sensory stimuli and make it interactive for people with different abilities.
In my first design, I worked on understanding the wiring (and since my computer was broken, it gave me something to brainstorm and visualize in the meantime) and started thinking about how the circuit would work, as well as the input/outputs.
In coding this, my thought process was, let me just make one button make one light light up first. Then, I wired it up so that there were 3 lights and 3 buttons, and each have a working input/output. Then, I had to figure out how to code for the buzzer and have it make a song. Then, the buzzer was isolated to have three separate notes, corresponding to a specific button each.
In this final design, I used a second breadboard to make the outputs separate so that in a future design, the breadboard part can be hidden and the lights and sound could be made in a way that would be easy to work with.
Final Product (playing Mary Had a Little Lamb)
I found the wiring part the hardest part (and almost created several short circuits and only didn’t because I had a friend point it out before I connected it to power!). The set up with the computer was also another source of stress because of several technical errors, but I found the old fashion take everything apart, turn off, and re-download worked really well. I learned how to label different inputs and how to wire everything to ground while playing with the microcontroller, and feel like i understand the breadboard much better now, too. I learned that the left and right sides don’t naturally connect, and you need to bring the ground wire over. I didn’t use any data sheets to figure out wiring components, but did use the sources below for inspiration.
Some potential uses for the microcontrollers in my life is in creating humidity sensors to automatically turn off/on my humidifier and dehumidifier (cause while they have sensors of their own, the two aren’t connected). Furthermore, when thinking about medical devices in prosthetics, robotic and sensing parts would be very cool to integrate into my future designs.
Sue and Moses posing in front of the Toyota Land Cruiser with their two dogs Gordon and Geko
I was inspired to make the Toyota Land Cruiser from my time this summer with Tufts Engineers Without Borders in Solomoni and Blantyre, Malawi. This car was the one me and 5 other travelers packed into from the airport to the village we stayed at for 8 days, and then back through town, and to the mountain where we backpacked for another three days. In making this laser-cut creation, I started with a hand sketch to figure out how exactly will everything fit together. I prioritized keeping the sides most realistic because this was the largest surface and this would give the creation its most defining characteristic.
I then took these rough sketches and worked on them using Google Slides for their initial shape. As shown below, there are interior seats, several parts for the top of the car, and its windows.
Right Side of CarBottom of CarTop of Car (left) and Wheels (right)Left Side of Car
To try to visualize this and fix the sizing of the parts, I printed the design on paper and fitted everything together.
Front Angle of Paper CarFront of Paper Car
For the side of the car (left above), there were some changes needed for the fitting of the wheel of the car. Also, there was some sizing issue for the side and hood of the car (middle and left above). For the bottom of the car (left below), there were some alignment issues with the chairs (ignoring the extra lines as they were a misprint). The chairs’ seats needed to be less wide and with tabs (middle below), while the back of the hood needed to be moved further from the middle and less wide.
Bottom of the carInside SeatsBack Hood
For the floors and benches (below), there needed to be some widening by the wheels and also taller bench sides in general.
Inside Benches
In an overall design issue, there was some worry I had about the thickness of the material lining up because it was hard to tell if there was going to be shrinkage and what the tolerance of the laser cutter was.
After some changes to the design, (above) I decided to try out a small section of the car to look at the sizing of the hole and tabs (below). The tabs themselves were too narrow, and the holes were too wide.
After uploading to Illustrator, there were some issues in the file so I had to unmask and change the line thicknesses. This proved to take more time than I expected and more difficult than I expected but it was okay because the line for the laser cutter was hours, which gave me plenty of time to mess around with my design.
I also worked on consolidating all of the pieces to cut on one piece to save material and time (above) and was able to get most pieces all together. I was only missing a back window and two wheels. When going to print, I had an issue where the files moved over in only black and white color (and only etched) and because I was short on time, I started the print, and while it was going, worked on isolating just the red lines.
After finally cutting on the Universal VLS 3.60 Laser cutter, I started putting together the pieces and found that the measurements did not line up perfectly as I imagined. With a heat gun, a little bit of hot glue, and a lot of willpower, I was successful in putting my car together! I repurposed the seats by making the legs the back of the chairs (because they fit perfectly while the back of the chairs were spaced weird). They needed a slight curve to them (top right), but otherwise it was perfect! The back of the chairs was used to hold the steering wheels (hot glued to the hood of the car), and some other side pieces’ tabs were bent so one of the two tabs could fit into the base of the car.
Objects that would be difficult to fabricate using something other than a laser cutter would be things with a lot of details, precise etching, or too thin be able to be hand saw or hand etch. The thin windows, curved circular wheel, and etching of little flowers are examples of this. Furthermore, a laser cutter ensures the same thing can be cut or etched over and over again almost exactly every time.
For this design, I used the printers in Nolop (Prusa i3 MK33) with PLA material and various orientation of printing. I tried optimizing this design by minimizing the material needed and print time with a simple design with as little supports as possible. This design also has good stability on flat surfaces and is hollow inside.
The difficulty was mostly sizing and trying to predict the tolerance of the printer.
For the first design, I over estimated the slope of the bottle, and made the bottom ring way too small. I tried to mechanically fix this, after some advice from a Nolop employee, using a heat gun, however this ended up not being enough because the heat weakened the material. I also did not wait long enough for the material to cool, and, when testing sliding the device on and off various water carrying containers, the forces cause the rings to have plastic deformation, breaking the device in three places.
For the next attempt, I had measured the bottle exactly to be around 59.4 mm, but there was shrinkage of the material after the shape cooled. I also attempted to increase the strength of the ring by printing up and down, compared to the slant before (which had used less printing material for supports). It somehow took less time to print, though, going from 3.5 hours to 2.5-3 hours. This orientation ended up weakening the handle, as the handle was the first to break. Furthermore, the ring and handle looked like over time there was separation where the handle met the ring (pictured on the bottom right in the photos below). It was later after a couple drops of the device did the rings of the device break.
With the next attempt, I decided to prioritize the strength of the handle by printing sideways, and attempted to size up in hopes to combat shrinkage after cooling. This made the item’s print time increase by two hours from 3.5 hours to 5-6 hours.
The issue with this last iteration was that the rings could not be attached to the tumbler with the force of the rings alone, as the diameter was too large. This was an issue that I had foreseen, but figured that a larger size would be a better issue because adding a rubber material or something with more friction than PLA would make device easier to put on, and have a stronger force to stay on.
The materials below are ones I found around Nolop to increase friction, and reduce the diameter of the rings. The first thing I tried was a clear silicone sealant. It did not dry fast enough, and ended up leaving a sticky, slimey cast on the ring. I then tried using the two small pieces blue tubing sliced in the middle and snapped onto the side of the rings, however underestimated the width and accidentally snapped the bottom ring of the device. Because of this, I added rubber bands to help with friction and kept one small piece of blue tubing on to keep the ring parts attached to each other, which worked pretty well. To try and increase friction for the upper ring, I extruded a lining of hot glue on the inside. However, the silicone sealant’s slimey cast made it impossible for the hot glue to stay on, and also left a slimey cast on the water bottle every time I put the device on the tumbler. I resorted to felt, which i sewed onto the top ring to keep it in place, and it worked perfectly! It was the perfect amount of thickening for the upper ring and also the perfect amount of cushioning for the device to be slid on.
It was only later, when I filled the tumbler, and took a sip, that the handle twisted, pulling on the already broken ring and snapping it in half, which also snapped the top ring in the process of me trying to fix it. Furthermore, when sipping from the tumbler, a little bit of water dripped down and made the felt wet, decreasing the friction with the side of the tumbler. I had forgotten that this fabric smoothens and flattens when wet, and was no longer effective in keeping the product from slipping down the tumbler.
While this particular design and product might not have been perfected, this shape would have been difficult to fabricate without 3D printing. Products that are difficult to fabricate without 3D printing ones with continuous shapes, irregular shapes, and designs with specific sizing that needs to be customizable to each individual. Prototyping is also a great use of 3D printing as rapid design changes can be seen within a couple hours. This product that I made most likely requires a bit more change in the design it self, but also a change in material (such as rubber, a stronger plastic, metal, etc…), or also an additional step after 3D printing such as sandcasting, molding, or something of that sort to add further strengthening support.
The inspiration for this design was a new coffee cup tumbler that I had thrifted a couple weeks ago. The problem that I was facing was the lack of a handle or holder so I would always tuck the cup into my backpack, or have to hold it in my hand, and it was always a little slipery. If there was a handle, then I could just use my fingers to grab it, and would leave the rest of my hand empty and useable to carry other things!
To solve this, I thought of a simple design, with two rings and a handle between it that could slip on to the cup like a coffee sleeve or a sippy cup handle. To do this, I needed three individual parts, that all worked in unison.
This design proved harder than I expected as I have had some experience with Solidworks, but not too much without some sort of direction and/or instruction. I had also not used the system in a bit so there was a bit of a re-learning curve.
After estimating the diameter of the tumbler, I started by trying to use a circle that was extruded and a hole cut in the middle, but I wanted to give the shape a bit of a curve on the inner edge so it would fit the cup better. The tumbler has a slight tapering to it, which seemed to require a different way of formation. I used the revolve feature to bring a parallelogram shape to a ring, and shaped it up a bit with the fillet/chamfer feature. Then, I copied the part and resized it to fit the dimensions of a lower ring, which is easier said than done.
To make the handle, I looked up the dimensions of a typical coffee mug or even door handle and found that most are around a third of the diameter of the vessel, so sized accordingly (with a little bit of give just in case). This was done using a sized rectangle for reference, and lines and curves to make the shape. I then tried to revolve around this sketch, but found it near impossible, so decided to extrude and fillet instead.
To bring everything together, I opened all the pieces in an Assembly, and worked on trying to mate the correct faces with each other. This also proved more challenging that I expected because I did not realize that a round surface would be hard to mate with a flat one. I tried adding reference lines that could potentially line up with each other and mate that way, but failed to do so sucessfully.
This was one of the things I would need to learn to advance further. It is quite difficult to test devices and ensure they are properly fitted without the mates. Furthermore, I would want to work on being more proficient in knowing how to size things more accurately (as one of the elements in the handle was not fully defined, but I could not figure out where and why). I would also want to learn more on how to properly show my design on the sketches because I don’t believe that the parts are show at their best angles, and all the dimensions are not what I expected them to be.
Hello World! My name is Natasha Wan, a current Junior studying Biomedical Engineering at Tufts University. In my free time, I love to hike, bike, crochet, thrift, sew, sing, and go on spontaneous adventures anywhere!
Natasha, Sophi, and Lexie in Chem Lab.
In terms of Biomedical Engineering, I am super interested in the extracellular matrix in bones and muscles and how these system work together to move, stabilize and so much more for the body! I want to learn more about physiology and also the field of medicine/engineering that looks into long term injuries and diseases people live with (ex. prosthetics, orthotics, occupational therapy, 3D printed/grown bone/organ replacement, etc…). I hope to continue to do more international engineering or healthcare work in communities that have less access to water and healthcare, and somehow tie BME into this mix.
