Reaction Injection Molding vs. Urethane Casting for Large Plastic Parts
RIM and urethane casting solve different problems at different scales.
Renata Solberg
Section
8 stories in Casting and Molding.
RIM and urethane casting solve different problems at different scales.
Investment casting often costs less per finished part despite higher per-kilogram prices.
Match steel grade to production volume, resin chemistry, then finish requirements.
Zinc handles finer features and tighter tolerances than aluminum die casting.
Predictable degradation curves let engineers plan mold replacement before quality collapses.
Temperature limits and chemical resistance determine which material survives the job.
Choose the process based on volume, tolerances, and geometry—not just once at the start.
Aluminum tooling often breaks even on total cost in the 100–500 unit range, if you run the math.