Vibratory Rock Tumbler Bounces on Printed Spring

If you’ve ever dabbled in rock tumbling, chances are you’re familiar with the classic rotary tumblers. But Fraens has taken a different approach with this innovative 3D printed vibratory rock tumbler. While rotary tumblers rely on simple rotation, vibratory tumblers like this one use controlled vibrations to achieve a fine finish on rocks and minerals, making them ideal for certain applications.

Rather than using a motor with an offset weight, Fraens opted for an electromagnet setup similar to what he used in a previous project: a vibratory bowl feeder. By pulsing the electromagnet, a 3D printed spring is pulled down, creating both vertical and horizontal motion. This unique tossing motion ensures that the rocks inside the chamber are evenly tumbled for a smooth finish.

Controlling the electromagnet is done using an Arduino and an L298N H-bridge motor controller, with potentiometers for adjusting the duty cycle. Interestingly, Fraens runs the electromagnet at 24 V despite its 12 V rating, giving the tumbler extra power. To prevent overheating, the Arduino code implements a cool-down period after every hour of operation, ensuring the longevity of the setup. Despite the unconventional approach, the tumbler has been running smoothly for months without any issues.

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