Un Redesign of an indigenous rice thresher for small farms in Córdoba, Colombia.

Abstract

Introduction: Colombian agriculture still has a low level of mechanization, which is primarily a result of the lack of financing, especially for small-scale farming. This has led to the artisanal manufacturing of agricultural machinery using local resources by copying other designs. This machinery generally has low efficiency and reliability. In the paper, the redesign of an indigenous rice thresher which was out of use due to its low efficiency and the significant rice losses during its operation is carried out.

Goal: The research is aimed at redesigning a homemade rice thresher, significantly improving its performance, with a low manufacturing cost through the maximum utilization of its components and reconstruction using local resources and infrastructure.

Methodology: For the redesign, the five-step methodology proposed by Mullineux was applied. All the machine's mechanisms were analyzed and redesigned, and completely re-engineered.

Results: A new design for threshing teeth called "comb threshing teeth" was introduced, very simple to produce, assemble and replace. The redesigned thresher was implemented and evaluated, achieving the same productivity as the original thresher, reducing rice losses by two-thirds. Also, the field assessment results were coherent with the results of the former research works.

Conclussions: The results  show that it is beneficial for small-scale agriculture in Colombia to manufacture agricultural machinery adapted to its specific needs, manufactured locally with its resources, but applying appropriate engineering methods to ensure that the performance of the machines is satisfactory.