Design and construction of a maize cob milling machine.

Abstract

Maize cob is one of the agricultural wastes Prom the maize crop among others include maize stalk mid leaves which are being used as a source of organic manure and at times as animal feeds. Maize Cobs Can be used as roughages that become available as livestock feeds after the crops have been harvested. Maize cobs have got some minerals and nutrient such as proteins, edible -fibre, calcium, potassium, chlorine, cellulose and many others. In Uganda, the increase in the price of maize due to high demands and exportation to outside countries like Sudan, has resulted into high increase in the prices of animals feeds majorly maize bran hence making animal rearing very expensive. The aim of this study was to make use of the available nutrients and minerals found in a maize cob to supplement animal feeds. This was be attained through the design and construction of a, maize cob milling machine powered by a motor. In achieving the above. goal, basic engineering principles, physical and mechanical properties of maize cobs were considered in the design of the various components of the maize cob milling machine. The machine was designed basing the crushing speed of maize cobs which ranges between 800 to 1400rpm, and crushing force of 860N and crushing strength of 5.4MPa. Software such as solid edge, AutoCAD and Matlab were used in the design of the intended machine. The machine was fabricated from readily available materials and common production technologies, including cutting, bending, welding, drilling, milling and others. The maize cob milling machine was designed and constructed by first sizing of the components through analysis of forces acting on the components, material selection, fabricated and assembled. The selected materials were those which would withstand the applied forces in order to avoid failure of the components during operation of the machine. After the fabrication process the machine was tested for its performance. A summary of the key findings included, the designed machine could be operated by at least a 3hp motor. The cost of prototype was 600000. After the machine had a production capacity of 7kg/hr of maize cobs with an average efficiency of' 84%. The percentage loss was 16%. Provisions was provided to change the sieve in case certain sizes of maize cobs were required. The- prototype had a limitation of producing a lot of noise and dust when operating. Conclusions and recommendation about the project are also included in this report.