| dc.description.abstract | The large and increasing production of beans in Uganda has posed a challenge of significant postharvest losses of produce during storage, preservation and transportation resulting from attacks
from pests, rotting and germination of seeds, as well as difficulty in handling respectively. This
necessitated value addition to bean produce through size reduction by milling.
This report therefore entails the project objectives of determining the requirements and
specifications of the bean milling machine, developing a preliminary and detailed design of the
equipment, and developing a simulation of the design of the equipment.
The methodologies used to achieve the project objectives included data collection methods, data
analysis, design, and simulation through motion simulations, Force analysis/ Finite Element
Analysis (FEA), and Photo realistic renders and animations. The machine was designed and
simulated using Solid Edge software, version 2020.
The designed machine consists of components that include the hopper (top casing) and the housing
(bottom casing). The bottom casing consists of a rotor assembly in which rotor plates are fixed to
the main shaft enclosed in some form of grinding chamber. The actual working mechanisms are
the hammers, which are swinging, and the round screens or grinding plates that are beneath the
rotor. These collectively crush the beans on impact. The rotor discs are welded to the shaft and
supported by bearings at both ends. This provides a more stable running mill and reduces the
tendency for a rotor shaft to wind up. The hammers are flat metal bars with holes at their ends to
enable fixation on the rotor. Other parts include; the frame, transmission bearings, drive pulley,
driver pulley, V-belt, electric motor, electric motor mounting, bolts, and lock nuts. The pulley on
the electric motor is connected to the pulley on the shaft via the v-belt. The shaft is suspended on
bearings mounted on their sitting on the two sides of the bottom casing. The bottom casing is
bolted strongly on the structural base.
Results obtained included the theoretical capacity of the machine, material physical properties,
maximum force and stress concentrations, maximum deflections for the different component parts,
and the Design Failure Mode and Effect Analysis (DFMEA).
In conclusion, the objectives were fully achieved with recommendations such as addition of an air
system, a cubbyhole and a magnetic system to separate seeds from unwanted heavy particles fed
in along with the beans. | en_US |
