Meaning
Protective enclosures produced by forcing molten polymer into a machined metal cavity provide both structural support and environmental defense for electronic assemblies. An injection molded housing is commonly used to protect smart sensors and wireless modules from physical impact and moisture ingress. The design of the mold dictates the locations of mounting bosses, snap-fits, and internal support ribs.
Material Selection
The selection of the thermoplastic resin determines the mechanical strength and chemical resistance of the finished enclosure. Common materials include ABS and polycarbonate, which provide a balance between impact resistance and ease of processing.
Internal Ribbing
The structural rigidity of the enclosure can be increased without adding excessive weight by using internal support structures. These structures also help prevent the plastic from warping as it cools within the mold. A uniform wall thickness is maintained to ensure even contraction of the material during the solidification phase.
Tooling Constraint
The creation of the mold requires careful planning to allow the finished part to be ejected without damage. Draft angles are incorporated into the vertical walls of the design to reduce friction during the ejection process. Undercuts and complex internal features increase the complexity of the mold by requiring moving slides or cores.
These features raise the initial tooling cost but can eliminate the need for secondary machining operations during assembly.
