A silicone mold is used in the manufacturing process known as “urethane casting” to create prototype and low-volume parts out of urethane. Materials that resemble plastic or rubber are used to make the parts.
With several advantages over other plastic manufacturing techniques like injection molding and additive manufacturing (3D printing), the process can be ideal for quantities up to about 25 parts. It is quick, affordable, and produces high-quality parts.
Speed
In contrast to injection molding, which uses hard tooling, urethane casting uses soft silicone molds, which can be made quickly. This leads to the urethane casting process being very quick. When quantities do not warrant investment in injection mold tooling, it is ideal for low-volume production.
Urethane casting is a quick way to get first-run parts made before the production tooling is ready if the intention is to injection mold a large number of parts, but some are required right away.
It is great for testing product designs, one-off products, or market or consumer reactions to new products. For end-user testing or short-run production, urethane casted parts can advance a project to the next level thanks to their quick turnaround time. A business may benefit from being first to market.
Cost
The liquid poured and cured silicone molds used for casting urethane are much cheaper to produce compared to creating injection mold “hard” tooling.
To put it into perspective, a casting project could cost just a few hundred dollars as opposed to the thousands of dollars that an equivalent injection molding project would cost.
The number of parts will dictate whether injection molding, CNC machining, or urethane casting is the best method for producing the parts. Urethane casting offers excellent value for prototypes and small-batch parts because the parts are made with high-quality materials at a very low price.
Quality
A variety of formulations can be used in the cast urethane process to create parts that are soft or hard, colored or transparent. The silicone molds offer superb surface finish detail and can faithfully replicate production textures.
Parts may also be over-molded, have inserts added to them, and receive post-processing treatments like painting.
The parts made by urethane casting are structurally superior to those made by 3D printing and have physical properties comparable to those of injection-molded parts. 3D printing – despite continuous improvements – still has material and structural integrity limitations. In contrast, urethane casting yields strong, high-quality parts.
