Mechanical

2-axis Vertical Gantry

Our finalized gantry is composed of aluminum 80-20 rails, custom 3D printed mounts, wooden housing, and three Nema 17 motors to control GT2 Timing belt pulleys Two motors controlled the y-axis movement and one controlled the x-axis movement.

Our gantry is 3 ft by 4 ft by 2 ft. We wanted to make it large to be as close to a real vending machine as possible.

Above: Up close shots of 3D printed mounts with the zip-tie attachment. While the zip ties may not have been the most elegant option to attach the belt to the gantry, it works well and is easily adjustable for belt tensioning.

Wooden housing

Our entire gantry and wooden housing is approximately 3 ft by 4 ft by 2 ft. We wanted to make it large to be as close in size to a real vending machine. All our wood was sourced for free. Our backboard is composed of a disassembled wooden hockey table with various rails and beams to hold the dispensers securely in place. We have two wooden boards that the four cup ramen dispensers are screwed into, as well as a platform for the kettle to sit up on top. As a finishing touch, we attached castor wheels at the bottom of the housing in order for it to be wheeled around easily.

Cup Dispensing

Our cup dispensing mechanism is made of wood, with rails on either side to guide our cup ramen. We spiraled wire made from clothing hangers that we found to be stiff enough to push our ramen forward.

3D printed wire mount and motor mount

Cup holder

First prototypes - 3D printed holder

Our first iteration of a cup holder consisted of three 3D printed parts press-fit together for a cup noodle to slide into it from the dispenser. We found through testing that the cup noodle was not constrained enough at the back and there was a risk of it falling out, potentially spilling hot water and noodles everywhere.

Final version - Wire basket and wooden mounts

The second and final iteration of the cup holder was devised using a decorative butterfly wire basket found from a thrift store. Not only did it hold the ramen securely in place, but we thought it looked more aesthetically pleasing than the 3D prints. Custom wooden mounts were created to attach it to the gantry.

Hot Water

To dispense hot water, we decided to hack an existing kettle that we got for free. A hole was drilled into the kettle which then connects to a food-safe valve through a bulkhead. A stepper turns the valve to open and close it with everything held with custom 3D printed mounts. A sharpened metal spike would be attached to spike water directly into the cup noodle.

Our first iteration of the kettle assembly utilized a stainless-steel ball valve meant for beer brewing. We used rubber tubing to connect our ball valve to a sharpened metal boba straw. This ended up requiring a lot of torque which was more than our Nema 17 stepper motor could provide. This was a big dilemma, but nothing that we can’t fix.

First & second prototype - Ball valve connected to a sharpened metal boba straw with tubing

Final prototype - Easier to turn valve directly connected to a sharpened copper toilet riser

We scrambled to Home Depot where we found a new valve that was easier to turn and fit all our temperature and food-safety requirements. The second version of our valve setup was much more successful and the custom 3D printed mounts ended up to be even simpler and cleaner. We have a copper toilet riser attached to the valve which we cut and sharpened in order for it to poke through the cup. There was no need for rubber tubing as the valve connects to our makeshift spike at a 90 degree angle.

Toppings

Our topping dispensing system was 3D printed with a servo motor to spin the inner portion of our dispenser, which is meant to allow toppings to drop onto our cup. We had issues with assembling our mechanism and having toppings drop reliably, so we decided to table topping dispensers until later.

List of motors:

3 Nema 17 motors (gantry)

1 stepper motor (valve)

4 DC motors (cup dispensers)