Overmolding: The Basics For Successful Optical Manufacturing

Overmolding, the process of molding plastic over another component, has long been used in manufacturing but is increasingly critical in optical applications. With the rise of miniaturized medical devices, wearables, sensors, and high-precision optics, demand for optical micro overmolding has surged. These applications require extreme precision, optical clarity, and flawless surface finishes that traditional supply chains often struggle to achieve, making micro molding expertise essential.

Two main approaches dominate: lead-frame micro molding and insert micro molding. Lead-frame molding involves guiding a continuous stamped metal strip through molding, where plastic is overlaid around it. This process, historically used in electronics, is now relevant in optics, where shielding, alignment, or electrical connections must coexist with lenses or light guides. Because lead-frame designs are often more complex than the final part, collaboration between designers, micro molders, and stamping providers is critical to prevent defects that compromise optical performance.

Insert molding, by contrast, involves molding plastic around individual components such as glass lenses, fiber optics, or coatings. It is flexible for both low- and high-volume production and often eliminates secondary assembly by consolidating multiple parts into a single component. However, insert handling during molding introduces design challenges, especially with delicate optical elements, requiring specialized tooling and micro handling techniques to maintain precision and clarity.

Ultimately, optical micro overmolding enables greater efficiency, integration, and performance in next-generation devices. Success depends on involving micro molders early in the design process to balance manufacturability with the demanding tolerances and surface quality required for optical applications.