Injection molding is generally more reliable and less expensive than stretch forming.
Furthermore, it allows for more complex shapes and eliminates the need for separate frame assemblies. Injection-molded polycarbonate performance is, however, more difficult to predict. This, combined with the stringent requirements for fighter transparencies, necessitates special efforts to ensure quality in design and production. One analytical design system for polycarbonate fighter aircraft canopies required a dozen different commercial and proprietary software tools. Separate solvers were needed for aerodynamic heating, thermal response, structural response, bird-strike dynamics, optical characteristics, and injection molding analysis.