Additive Manufactured Break-Out Cores for Composite Production: A Case Study with Motorcycle Parts

Abstract

To produce hollow-shaped, lightweight composite structures made out of fiber reinforced polymers (FRP), many manufacturing processes require a shape-giving tooling in form of a core. Additive manufacturing (AM) offers the potential to fabricate such tools and production aids with increased geometric complexity and functionality at reduced costs and lead time. An AM core can remain inside the produced composite part and provide additional functionality such as the integration of metallic inserts. A core can also be removed from the final composite part to reduce the part mass. To enable the removal of a core, a promising approach is to use AM to design and produce a core in form of thinwalled shell that integrates breaking lines. After curing of the composite part, the breaking lines are used to break and disassemble the core into smaller patches, which are removed through an opening of the cured composite part. To stabilize the core shell during composite production, it is filled with a filler material such as salt. Although AM break-out cores offer many benefits, only a limited amount of works exists that study such cores. Therefore, this work contributes novel concepts for the design of AM break-out cores. The focus lies on the use of perforated and continuous breaking lines to enable a controlled fracture of cores. A case study demonstrates their application to produce parts of a motorcycle including the flow intake and tank structure. After the case study, the work discusses possible improvements and outlines future research directions.