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Picking The Right Manufacturing Process: Reaction Injection Molding vs Thermoplastic Injection

Reaction injection molding, commonly referred to as RIM, is a process where two liquid polymers are combined and then injected into a single heated mold. When these polymers are combined and blinded, they begin a chemical reaction that allows them to expand to fill the mold, then set into a solid part. RIM is definitely an option worth considering as an alternative to thermoplastic injection for several reasons, we’ve listed the top three reasons below:

Reason #1: Design features

Although both processes allow for various features to be incorporated into a mold, only RIM gives the designer the flexibility to produce parts with significant wall thickness variations. Reaction injection molding can also create larger parts at a lower cost since mold pressures are significantly lower compared to thermoplastics. RIM molds over metal, glass, wood, wiring, circuit boards, and hardware.

Reason #2 Volumes

Reaction injection molding is extremely valuable for producing high and low volumes at a low cost. This can be beneficial especially if you are a launching a new product and it’s in it’s testing phase. This will allow you to evaluate market success before continuing to produce higher quantities, leaving RIM the more cost-effective processing option. Not only can you create higher volumes at a lower cost, but reaction injection molding has shorter tooling lead times in comparison to thermoplastic injection molding.

Reason #3 Tooling costs

When moving from the prototyping phase to large quantity production, reaction injection molding requires a double sided mold which is very similar to the molds used in injection molding. Since RIM can be created from aluminum instead of steel, the tooling costs are typically half the amount of a comparable thermoplastic mold. If you are looking for high volume and large size, reaction injection molding is the most cost-effective choice than thermoplastic tooling options.

At Romeo Rim, our innovative approach to solving complex engineering challenges makes us the nation’s first choice for reaction injection molding. Our ISO-compliant, low-viscosity RIM services provide parts with a variety of unique product benefits, including Class A surfaces, wall thickness changes, high impact resistance, encapsulation of inserts, and in-mold coatings. We have complete solutions for transportation, heavy truck, agriculture and construction and spas. Since 1982, we have been providing smarter molding solutions for our customers. Contact us today at 586-336-5800 or request a quote.

Romeorim design guide