Design of a multi-piece removable mandrel mold tool to fabricate and control inner mold surface contour of a composite wing spar

Composites technologies are advancing at a rapid rate. As engineers continue to find new ways to us fiber reinforced composites, the need for advanced tooling is greater than ever. In the ever expanding aircraft industry, wing spars are one of the most critical parts on the aircraft and typically require expensive custom tooling. They provide structural support for the entire aircraft under strong aerodynamic loading. The spars must be manufactured to the highest aircraft standards.;Many spars have closed section geometry which provides even more difficulty in the manufacturing and tooling process. Not only does the tooling have to be used to manufacture production rate composite parts, it must be fabricated and maintained to higher standards than the parts themselves. The original mandrel tool is disposable after every cycle and has too many variables in the manufacturing process to produce quality composites spars on a regular basis. The goal of the new design is to create a reusable tool and reduce the variability in the manufacturing process. This was accomplished by utilizing the unique structural properties of multiple materials machined to tight tolerances working in unison to create a mold tool. This tool can then be used as the primary component in the manufacturing process of a specialized composite wing spar. The following work describes the complete design and development of the new multi-piece removable mandrel tool.