Design and Performance Evaluation of a Manually Operated Grinding Machine for Sustainable Household Food Processing

Abstract

This study presents the design, construction, and performance evaluation of a manually operated grinding machine intended for household food processing in low-resource and off-grid settings. The machine was developed as a sustainable alternative to electric and fuel-powered grinders, particularly for rural communities with limited access to reliable energy sources. The design incorporates an ergonomically contoured hand crank, a torque-amplifying gear system, and durable grinding discs mounted within a compact, lightweight frame constructed from cost-effective materials. Performance evaluation was conducted using five common food items: maize, millet, dried pepper, coffee beans, and rice, each processed in 500-gram batches. Key performance indicators included grinding time, particle size uniformity, and user effort, the latter measured with a digital force gauge. Results showed that the grinding time ranged from 6 to 15 minutes, depending on the material, while particle size uniformity reached up to 95% for softer items like dried pepper. User effort varied between 18 N and 30 N, with maize requiring the greatest exertion. Durability tests confirmed mechanical stability and operational consistency over multiple cycles without component failure. The findings indicate that the grinder is particularly effective for soft to medium-density food items, offering a viable solution for household-scale food processing in energy-constrained environments. However, challenges such as high user effort for harder grains suggest opportunities for further improvement in ergonomic design and mechanical efficiency. The study concludes by recommending enhancements such as flywheel-assisted operation, modular attachments, and long-term field validation to broaden the device’s utility and impact.