Liquid Silicone Rubber Injection Molding: A Review of Material–Process–Quality Relationships

Liquid silicone rubber (LSR) injection molding produces elastomeric components with complex geometries and demanding functional requirements through coupled flow, heat transfer, and crosslinking. This review examines how formulation, processing conditions, and equipment operation jointly affect part quality. Literature was identified through Web of Science and Google Scholar searches and citation tracing, with no lower publication-year limit and a search cutoff of September 2026. Rheological behavior and curing kinetics underpin the discussion of material delivery, cavity filling, and demolding, alongside equipment technologies for metering, injection, thermal management, and process monitoring. Available evidence links processing history to shrinkage, surface replication, mechanical properties, and defects. Biomedical, optical, multi-material, and soft robotic applications illustrate how functional requirements guide manufacturing choices. Processing conditions influence multiple quality outcomes simultaneously, requiring their selection to account for formulation, geometry, and intended function. A key gap remains in linking process signals, independently characterized material states, and effective control actions across formulations and molds. Future priorities include material-state-based control, thermal efficiency, silicone reuse and recovery, and hybrid manufacturing. By relating equipment functions to material responses and measurable quality outcomes, this review supports application-specific selection of processing and evaluation methods.