ADDITIVELY MANUFACTURED TOOLING FOR PRODUCING ELLIPTICAL DISH COMPOSITE STRUCTURES USING AUTOCLAVE CURING

Elliptical dish structures are used in various applications, especially in aerospace. The best way to manufacture this structure is using fiberglass-reinforced polymer matrix composite materials. Composite materials offer different advantages to creating an elliptical dish, such as their lightweight, high strength, and improved radio frequency (RF) efficiency. An elliptical dish structure is necessary for RF applications because it can focus and direct signals with high precision, improving signal strength and clarity. Further, proper material selection is essential before manufacturing the finished product so that it can provide the required factors to achieve these advantages. First, a mold is needed to fabricate and lay the fiberglass/polymer materials that will be consolidated, typically in an autoclave. The typical mold-making approach involves computer numerical control (CNC) machining, which is time-consuming, expensive, and requires skilled labor. Additive manufacturing (AM) offers the advantage of creating rapid prototype tooling at a lower cost and less time, making it particularly beneficial for low-batch productions. Fiberglass with polycarbonate and carbon fiber reinforced PA6 (nylon 6) were two types of filament material used in this work to 3D print molds with approximate dimensions of 25 cm diameter x 8.5 cm high. Three different infill densities were used to study the effect of mold density on dimensional change during autoclave curing. The 3D printed tool was then used to manufacture the finished composite of elliptical dish structures. Details of the prepreg layup process, vacuum bagging, and cure cycle will be discussed. The final composite part was evaluated for surface finish and structural integrity, while the tool was evaluated for shrinkage/compaction during cure.