Due to high competition of the agriculture machines sector, the auto parts suppliers are investing in research to promote the development and reduce the costs of the products, passing these results to their clients who are the automakers. It was identified the need to redesign the regulation sieve system harvester, which is a compound assembly in the harvester's grain cleaning system, with the objective to reduce the costs and improve the ergonomic aspect, keeping the same efficiency from the original project. The improvement was developed by studying the original design and identifying possible project fails, such as components and manufacturing process which could be eliminated. For this, it was needed to do a research about rules and project considerations that must be applied in the products development and ergonomic too, specifically about geometric forms and anthropometric measures. From the redesign of this system, it is verified that it is possible by a study to identify possible improvements, and to develop a new system by a simple project, improving the ergonomic, reducing the cost and keeping the same efficacy from the original project.