The HMD (Helmet Mounted Display) visor is a sophisticated article. It is both the optical combiner for the display and
personal protective equipment for the pilot. The visor must have dimensional and optical tolerances commensurate with
precision optics; and mechanical properties sufficient for a ballistic shield. Optimized processes and tooling are
necessary in order to manufacture a functional visor. This paper describes the manufacturing development of the visor
for the Joint Strike Fighter (JSF) HMD. The analytical and experimental basis for the tool and manufacturing process
development are described; as well as the metrological and testing methods to verify the visor design and function.
The requirements for the F-35 JSF visor are a generation beyond those for the HMD visor which currently flies on the
F-15, F-16 and F/A-18. The need for greater precision is manifest in the requirements for the tooling and molding
process for the visor. The visor is injection-molded optical polycarbonate, selected for its combination of optical,
mechanical and environmental properties. Proper design and manufacture of the tool - the mold - is essential. Design
of the manufacturing tooling is an iterative process between visor design, mold design, mechanical modeling and
polymer-flow modeling. Iterative design and manufacture enable the mold designer to define a polymer shrinkage
factor more precise than derived from modeling or recommended by the resin supplier.
The manufacturing design and process development for the Visor for the JHMCS (Joint Helmet Mounted Cueing System) are discussed. The JHMCS system is a Helmet Mounted Display (HMD) system currently flying on the F-15, F-16 and F/A-18 aircraft. The Visor manufacturing processes are essential to both system performance and economy. The Visor functions both as the system optical combiner and personal protective equipment for the pilot. The Visor material is optical polycarbonate. For a military HMD system, the mechanical and environmental properties of the Visor are as necessary as the optical properties. The visor must meet stringent dimensional requirements to assure adequate system optical performance. Injection molding can provide dimensional fidelity to the requirements, if done properly. Concurrent design of the visor and the tool (i.e., the injection mold) is essential. The concurrent design necessarily considers manufacturing operations and the use environment of the Visor. Computer modeling of the molding process is a necessary input to the mold design. With proper attention to product design and tool development, it is possible to improve upon published standard dimensional tolerances for molded polycarbonate articles.