Design and Construction of a Posho Mingling Machine.

Abstract

In Uganda, posho (maize meal) is a staple food widely consumed in homes and institutions; however, its preparation remains labor-intensive, unsafe, and inefficient. The traditional method involves manual stirring of boiling water and maize flour, exposing cooks to health hazards and inconsistent food quality, especially in large-scale settings like schools and prisons. This project aimed to design and construct a semi-automated posho mingling machine that addresses these challenges. The key objectives included identifying design requirements, developing CAD-based concepts, fabricating a functional prototype, and testing its performance. The methodology combined literature review, interviews with institutional cooks, and parametric design using mechanical and electrical engineering principles. The final prototype incorporated a stainless-steel mixing pan, an open agitator driven by a 1HP singlephase AC motor, and an LPG-powered heating system. Testing showed that the machine significantly reduced cooking time, improved safety, and ensured consistency in posho texture, especially with higher water-to-flour ratios. The open agitator proved effective across various mixing conditions, while the closed agitator was optimal for watery mixtures. Recommendations include using stainless steel grade 304/316 for all food-contact parts, integrating automation with sensors and microcontrollers, and scaling up for larger capacities. The project supports several Sustainable Development Goals (SDGs), particularly in the areas of food security, clean energy, and industrial innovation.