Material choice changes the manufacturing route. Acetate frames depend on machining, hinge work, polishing and fitting, while injection frames require mold engineering, tooling and repeatable molding control.
Titanium and metal constructions bring a different set of forming, joining, finishing and component decisions. Combination frames require these processes to meet within one coherent product specification.
Sabae Optical reviews the complete frame rather than treating each operation in isolation. This helps identify the factory capabilities and specialist handoffs needed to carry the design through production.