Adaptive Pellet Dispenser
Programmable pellet dispensing that blends PETG and TPU as it prints.
The adaptive pellet dispenser is a digitally controlled material delivery system developed for variable-ratio feeding of PETG and TPU pellets during robotic fabrication. Two independently driven augers regulate the amount of each material entering the system, allowing the composition to change according to ratios defined computationally in Grasshopper. An ESP32 microcontroller receives these commands wirelessly and coordinates the feeder motions, mixing process and iris valve operation. The incoming pellets are transferred from separate hoppers into a shared mixing chamber, where a continuously rotating mixer combines the materials before discharge. Encoder-equipped stepper drivers provide positional feedback for the augers, enabling repeatable indexing and controlled return to defined home positions. The system also incorporates an automatic anti-wedging routine that briefly reverses and advances an auger when stalled motion is detected. By coordinating digital input, material metering, blending and release, the dispenser enables programmable variation of material composition within a continuous fabrication workflow.