Design for additive manufacturing applied for mass reduction of a two-stroke engine cylinder for portable machine

Abstract

Metal additive manufacturing is an evolving technology not yet economically feasible for massive scale employment, but already profitable for low production volumes, especially in high-value-added segments, as well as being dominant in the prototyping industry. Since it provides significant design freedom compared to traditional manufacturing methods, it is suitable for lightweight projects with application of optimization software and bold concepts. Combustion engine cylinders for portable machines are complex parts that requires high investments for tooling construction of aluminum casting, which keeps the component geometry under its physical limitations. The advantages offered by the design freedom of the additive manufacturing becomes evident, through the results of this paper, where 27% of mass was reduced in an engine cylinder model by removing the draft angles of the cooling fins and adjusting their thickness, besides the addition of lattice structures into the crankcase flange. The lattice structures design took into account the printing limitations and their mechanical strength was evaluated through structural simulation, keeping a tensile range comparable to the original geometry. Due to its high potential for functional optimizations, additive manufacturing technologies advances should remain under the industry development focus areas, since it could become relevant to the future discussions in the portable machine cylinders production field.