Objectives:
- Design a machine (mechanism+automation), including the end effector Pump Design,
- Build the passive parts and operate it manually
- Document the group project and your individual contribution
- Group work page -> Link
Intro
During this week we decided to build a machine able to dispense fluids into test tubes.
The idea is to have one or multiple peristaltic pumps to select from one or multiple tanks, different liquids. The test tubes will be placed in a rotating platform, each test tube will have a colorful ring so that we can, thanks to a webcam, recognize the color and dispense the right combination of liquid.
The part i’ll handle is the end-effector and the peristaltic pump.
Design of the peristaltic pump
The first step in order to design the peristaltic pump was to measure the thickness of the silicon tube when tight.
After i designed the component that will hold the 3 bearings trying to minimize the lever so that the force required is minimized. At the end i designed the outer shell of the peristaltic pump.
At the first try the pump wasn't pushing enough the tube to the outer wall, resulting in a pulsing flow at high speed and no flow at all at low speed. I increased the diameter of the spinner by 1 mm and tried again, this time the pump was working but the stepper was losing steps. I upgraded the power supply from 12v to 24v to make the pump work smoothly.
