3D-Printed Magnetic Stir Plate

When you need to mix a liquid or slurry, typically this means physical stirring, e.g. a spoon for batter, or even rotating the substance’s container, e.g. cement mixing drum. What if, however, you need to mix a liquid without rotating the container, or even physically reaching in with some sort of stirrer? One popular method, often used in chemical experimentation, is called a magnetic stir plate.

This clever device consists of a magnetic agitator inside of a beaker or other liquid container, which appears to magically rotate when placed on its base. Inside this base assembly, a motor drives a magnetic coupling circuit which moves the stirrer, allowing it to mix liquids without any physical attachment. You could simply buy a magnetic stirrer, but as shown in this write-up, you can also 3D print your own stirring assembly with the addition of a motor and PWM controller.

Stirrer files can be found here, and after just under 10 hours of print time and around 70g of filament, you’ll have a nicely printed base and agitator. User interface consists of a simple potentiometer to define the speed via PWM control. Once set up, the devices spins your beaker-bound fluids at the proper speed until it is deactivated.

Of course, one could see this project expanded in any number of ways. A Hall effect sensor and microcontroller could count how many revolutions the driving motor has made. Perhaps it could even have a reversing function for some creative fluid movement applications!