Automatic Weighing Station (2)

Cosmetics manufacturers face huge financial and reputational risks when products fail to meet specified weight standards, often relying on slow manual inspections that miss defects. This project addresses that problem by designing an Automatic Weighing Station (AWS) capable of checking 60 bottles per minute. The team developed a mechanical structure and integrated a strain gauge loadcell, testing the system under both static and dynamic conditions to evaluate accuracy. While dynamic testing revealed high vibration noise, static testing proved highly linear and reliable. As a result, the final design weighs bottles statically using the star wheel’s inherent “pause” time, guaranteeing accuracy without reducing production. The system was further developed through full mechanical design and component selection, including a NEMA 34 stepper motor rated at 8.5 Nm, a solid shaft with a final diameter of 15 mm designed based on combined loading conditions, and a dual star wheel configuration with 12 pockets selected to enhance stability during indexing, along with a pneumatic rejection mechanism to automatically remove noncompliant bottles. The design was then expanded into the fabrication phase, where a prototype was manufactured and assembled using a combination of 3D-printed and machined steel components, integrating the structural frame, weighing platform and loadcell, star wheel system, and automation components into a fully assembled AWS unit. The final system guarantees regulatory compliance, minimizes waste from plastic and products, supports sustainable and efficient manufacturing practices aligned with key development goals, and provides a projected return on investment in about eleven months.

Project Details

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