When To Use Reaction Injection Molding

Reaction injection molding (RIM) is a highly advantageous manufacturing process that produces molded parts for a wide range of industries. Since its conception, RIM has been utilized to create aesthetically pleasing, functional parts for a variety of applications including medical devices, laboratory equipment, electronics, vending and gaming kiosks as well as robotic enclosures.

To determine whether RIM represents a suitable manufacturing process for your current project, please consult the helpful guide below that highlights critical RIM selection criteria.


If your tooling budget is limited, reaction injection molding can provide an economical option as its tooling costs are lower than those associated with injection molding and other popular molding methods.

Traditional injection molding tooling requires expensive steel materials because of the considerable stress placed on the tooling when thermoplastic material is injected forcefully into the mold. Reaction injection molding only necessitates machined aluminum to create high-quality tools because the reaction injection molding process exerts substantially less pressure on its tooling due to the low viscosity and temperature at which the material is injected into the mold. As a result, reaction injection molding tooling can be produced quickly at a lower cost with high levels of quality and durability.


The ideal production volume for a reaction injection molding project typically ranges between 100 and 5,000 parts annually. Low to medium production volumes are particularly compatible with reaction injection molding because RIM’s cost-effective tooling process can offset its production expenses in lower quantities.

While reaction injection molded parts may possess elevated individual part prices due to RIM’s utilization of secondary operations to finish and process manufactured products, these slightly higher costs are often outweighed by the financial and operational advantages of reaction injection molding’s low-cost tooling. RIM tooling has shorter lead times, is easier to modify and typically costs tens or hundreds of thousands of dollars less than the tooling necessary for competing manufacturing processes.


Projects requiring the creation of larger, intricate parts are another instance of when to use reaction injection molding. As a rule of thumb, if you are constructing a product that is larger than the phone on your desk, there is a strong likelihood that reaction injection molding could represent a viable manufacturing solution. RIM’s low molding pressures and temperatures enable the process to produce larger parts at a much lower price than competing processes.


Reaction injection molding offers an unprecedented level of design freedom and flexibility for engineers building large, detailed three-dimensional parts. RIM’s unique capacity to supply complex, durable parts stems from its use of low viscosity liquids that can exhaustively fill even the most extensive geometries without applying immense pressures or temperatures. These polyurethane materials can also be adjusted to generate a final product with structural characteristics that closely reflect its application.

Reaction injection molding for complex parts affords product designers additional creative liberties including the ability to create parts with varying wall thicknesses, curves and encapsulated components.

Another reason to consider the reaction injection molding process to manufacture your part is if your project requires the integration of additional functionality into the final product. In such instances, RIM allows for the implementation of low-pressure overmolding due to the low viscosity of the material as well as the process’s reduced temperature and pressure requirements. By leveraging low-pressure overmolding, RIM can effectively mold additional components into parts to enhance their functionality without utilizing costly, time-consuming secondary operations.

If you are still unsure whether reaction injection molding is the right process for your application, our team at Rimnetics can help. Please send us your files and our experts will review them to determine if reaction injection molding represents a technically and economically advantageous option. With over 30 years of industry experience, we know exactly what it will take to make your project a success story at the lowest possible price. To learn more about our services and processes, contact us today.

Similar Posts