Project Milk and Tea involved creating an automatic coffee and tea dispenser. Such a machine is often available in hawker centres (including the drinks stall in South Spine) and not exactly considered a novel idea. However, since our group did not have anyone with engineering capabilities, it was certainly challenging enough to implement within the course timeline. Our first informal presentation dove into the intricate details of the dispenser, with our initial plan involving rotating tracks and enormous containers.
We planned to 3D print the rotating track and cupholder, using motors to rotate the track. We designed a circular container with six compartments, five of them for our five main liquids; tea, coffee, sugar syrup, condensed milk and evaporated milk, as well as for the machine interface. We also narrowed down on using peristaltic pumps to transport each liquid from the compartments into the cup. With the initial research we did on the motors and pumps we could use, we felt confident to tackle the project. That is when the problems began.
The first problem we faced was with the peristaltic pump. It remained a consistent problem for multiple days as we tried to find alternatives. The available peristaltic pumps were simply not fast enough to transport liquids into the cup. The flow rate was slow such that we realised it would be faster to pour out the liquids by hand than to use the pump. This began our search for peristaltic pumps with faster flow rate.
We also realised that the liquids we planned to use were not suitable to be kept out of the fridge for more than four to six hours. Using condensed milk and evaporated milk would require us to refill the compartments every four hours to prevent the liquids from spoiling. This contradicted our aim to make the machine such that it would require as little manual labour as possible.
Lastly, we found that the peristaltic pump was not suitable to transport condensed milk. Due to the thickness of condensed milk, the pressure applied by the pump to push the liquid through the tubing was insufficient, urging us to find drink recipes without condensed milk.
These issues led to us switching the liquids used in our drinks dispenser, until we decided on our final idea; an automatic milk tea dispenser.