Análise comparativa entre dois mecanismos de retorno rápido para plaina limadora

Abstract

This undergraduate thesis presents an analysis of a quick-return mechanism, aiming to replace the crank shaper mechanism currently used in shaping machines. The objective of this work is to design and analyze the optimal configuration of the chosen mechanism by varying its dimensions and observing how this influences the system's time ratio. The shaping machine is utilized in machining processes such as top-facing, chamfers, and keyways. The machine operates in a cycle of forward stroke (working) and return stroke (non-working); therefore, it is ideal to reduce the return time through a superior quick-return mechanism, as this would reduce time wasted in the overall process. The six-bar mechanism was chosen for comparison with the crank shaper mechanism. The selection and methodology were based on a literature review, where concepts and rules for the construction of quick-return mechanisms were analyzed. The criterion that determined the six-bar mechanism as the best candidate was the time ratio, which analyzes the return and forward angles of the system. Based on equations from the literature, an Excel spreadsheet was used to vary the system's dimensions and analyze the resulting variation in the time ratio. Dimensional criteria were respected, and through this process, the optimal dimensioning was determined, achieving a superior time ratio compared to the system currently present in the shaper. The system was modeled in AutoCAD to illustrate the best possible dimensioning, following the work's objectives.