Blog | RIM Injection Molding Insights

8 Applications of RIM | Thieme

Written by Thieme | Mar 15, 2023 8:36:00 PM

Molded plastics have a wide range of commercial and industrial applications—from the smallest, most intricate electronics to heavy machinery, plastic parts are everywhere. 

There are many specific molding processes to choose from, and each manufacturer must choose the most efficient way to mold these plastic parts for their products. One of the most popular manufacturing processes for producing high-quality plastic parts is reaction injection molding (RIM)

RIM is a specialized subset of the traditional injection molding process. It is used in a variety of industries and for many types of parts, and for certain applications, RIM is more economical, quicker, and more effective than injection molding.

Reaction Injection Molding Applications

The RIM process is commonly used to fabricate low volumes of large, complex parts, making it well-suited to industrial and commercial products that require intricate or bulky components.

Here are a few of the most common applications of reaction injection molding.

1. Products Exposed to High Temperatures

Household and kitchen appliances as well as some medical devices tend to generate heat. While products made from the thermoplastic resins used in traditional injection molding could warp, melt, or damage electronics when exposed to heat, RIM products have incredible heat resistance. That makes reaction injection molding ideal for products exposed to higher temperatures.

2. Products That Need to be Durable and/or Chemically Resistant

RIM products are resistant to heat, water, and chemicals like corrosive acids and solvents. Additionally, they are highly durable because the resulting polyurethane plastic parts are more resistant to wear and tear than products produced by injection molding. Heavy equipment consoles, medical device covers, recreational vehicles, and other products with plastic parts can benefit from the durability and chemical resistance of RIM.

3. Products with Complex Parts and Varying Wall Thicknesses

The RIM process is well-suited for creating parts that require design flexibility, such as analytical machines in the medical field, electrical enclosures, or panels and doors for a variety of plastic parts. With the low viscosity materials used in the process, manufacturers can use intricate molds to construct highly complex parts with curves, encapsulated components, and more. 

Similarly, RIM-produced parts can have varying wall thicknesses. While injection molded parts must be uniform in order to prevent the part from deforming as it cools, RIM allows for varying wall thicknesses within the same part without built in stress, sink or distortion in the part.

4. Large Component Manufacturing

Thanks to its ability to handle complex designs, deep draws, strength-to-weight ratio, and smooth, cosmetic finishes, RIM is a popular choice for large component manufacturing, such as automotive bumpers, large covers for machines such CT’s or MRI’s, gas pump covers and mass transit fare vending covers.    

Producing a large component through injection molding requires the production of several smaller parts that then need to be assembled to create the whole product. Alternatively, manufacturers can use RIM to produce one large component—eliminating the costs and resources required to assemble smaller injection molded parts into one larger piece.

Especially in smaller volumes of less than 5,000 units, RIM is a low-cost option for manufacturing large components.

5. Products with Encapsulated Parts

Magnets, batteries, hinges, antennas, threaded inserts, circuit boards, metal rods, and other fragile items can  be directly encapsulated into plastic parts to reduce cost and increase quality.  

6. Products That Benefit from Fewer Parting Lines

RIM allows for a superior cosmetic appearance and reduces the number of parting lines on plastic products. Since manufacturers can use RIM to encapsulate items into a plastic part as well as produce larger, complex parts in one piece, the process minimizes seams, parting lines, and weak points that might detract from the product’s appearance. Applications include products like device or electrical enclosures or housings as well as panels and doors on medical equipment.

Contact Thieme for Help with Your Next RIM Project

At Thieme, we offer custom reaction injection molding for a wide range of devices and industries. With our RIM technology and process expertise, responsive service, and exceptional approach to project management, we are proud to serve as a trusted supplier of large format molding for our local, national, and global customer base.

We specialize in customized RIM projects in a variety of industries and applications, including device enclosures, structural parts, analytical instrumentation, medical device parts, and various industrial devices and machinery. Additionally, you can explore our options for large format molding for heavy equipment, automotive, medical, and other industries.

Are you ready to upgrade your approach to reaction injection molding?

Our experienced full-service team is ready to help you with every part of your next RIM project, from conception and planning to production and fulfillment. Contact us today to request a consultation and discover how you can benefit from our RIM services.