SUMMARY

Conventionally, thin-walled structures are manufactured through a high speed machining process on a solid block of material, resulting in large material waste and increase in tool wear. By utilizing additive manufacturing, a near-net shape of the thin-walled structure can be produced; however, post-process machining is required to achieve the desired dimensional tolerance and surface finish. Difficulties occur when machining these additive thin-walls due to having low-rigidity, which lead to large workpiece deflection caused by cutting forces. These large deflections cause unintentional uncut material that affect the overall dimension of the part. Printed sacrificial supports can be added onto the thin-walled structure to increase the part’s stiffness and reduce machining induced deflection. Although sacrificial supports can be utilized, there is a lack of research on where these supports should be placed and the number of supports needed to effectively increase the rigidity of the part. Having a better understanding on support location and effective number of supports can help reduce the total build volume as well as providing insight on proper support placement. Experimentally, this can be expensive and time-consuming as it requires the need to produce these thin-walled structures and measure the machining induced-deflection. In this work, a finite element model for machining induced deflection of additive thin-walled structures with sacrificial supports was developed. First, the model framework was validated by comparing the predicted deflection with experimental results on an unsupported thin wall. A square shaped tube with varying side lengths was used as the thin-walled structure model. The number and location of sacrificial supports were varied for each simulation. Each simulation generates workpiece deflection data which are used to understand the effects of the number of supports and the placement of supports on workpiece deflection.