Injection Molding for Medical Devices

Reaction injection molding is an ideal production method for larger, more complex equipment that is manufactured in low volumes, such as medical devices. Many medical devices, particularly the more expensive ones, are sold in small quantities, ranging from a few hundred to several thousand per year. Consequently, the medical device industry heavily utilizes reaction injection molded products. Reaction injection molding for medical devices hits the sweet spot where the process is highly efficient and affordable while allowing for an attractive design that enhances the market appeal of medical devices. Continue reading to learn more about medical device injection molding and why reaction injection molding (RIM) is ideal for large medical equipment.


While there are various manufacturing processes theoretically capable of creating large medical devices, such as traditional injection molding or thermoforming, these methods often are not economical.

When it comes to producing high-quality, complex medical devices in low volumes, reaction injection molding is the most cost-effective production method. The affordability of reaction injection molding for large, intricate medical devices stems primarily from the low tooling costs associated with RIM. If your annual production involves only a few hundred or thousand devices, it’s more advantageous to create a low-cost tool.

The cost of creating a tool large enough to mold sizable medical parts is exponentially higher for traditional injection molding compared to reaction injection molding. Therefore, even though the price per part might be higher with RIM than other molding processes like conventional injection molding, the low cost of the large tooling required significantly reduces the overall cost of production. As a result, reaction injection molded medical devices can be produced in a much more cost-efficient manner when using reaction injection molding as the production method. Numerous factors, including the aesthetics of the device, should be considered when selecting a molding process.


Reaction injection molding for medical devices offers the advantage of creating aesthetically pleasing medical equipment. This process goes beyond crafting boxy, metallic devices with an unoriginal look, enabling the production of medical devices that appear as sophisticated externally as they are internally. Medical device plastic injection molding boosts the appeal of the medical devices, which allows them to outperform machines with simple box-like features.

Reaction injection molding differentiates itself from other manufacturing processes by allowing the creation of attractive parts featuring curves, different wall thicknesses, and expansive appearances. RIM molding also offers enhanced structural support for the machine’s internal components by integrating the part’s structure into the design itself. For example, if a support structure is needed, it can be built into the design, resulting in smooth, curved shapes rather than a simplistic, boxy exterior.

Many manufacturing processes don’t offer the option to include structural support within your part’s frame or structure. As a result, numerous devices leverage a box-like structure and an internal metal frame to hold the components together. However, with reaction injection molding, the product’s exterior can be designed to support the interior components, transforming the external parts into the structural framework of the product or medical device


Reaction injection molded (RIM) parts are highly durable. RIM parts can be produced to be wear-resistant, physically strong, and dimensionally stable. Such durability is a necessity when creating medical devices that undergo substantial use to provide medical assistance or essential testing.

In addition to resisting wear and tear, reaction injection molded parts can be chemically resistant. Many coatings applied during the production of reaction injection molded parts can withstand exposure to chemicals and completely protect the part from damage. Therefore, a wide variety of cleaners and solvents can be used to sanitize and disinfect reaction injection molded parts. This durability is ideal for medical devices that must be cleaned and sanitized frequently with a wide variety of potentially harsh disinfectants.


Medical devices are inherently complex, often including numerous different parts that need to be assembled. When creating complex medical devices with other molding processes, multiple parting lines often appear when different parts are attached together. With reaction injection molding for medical devices, you can consolidate features and functions to effectively reduce the number of parts.

Due to this benefit, the resulting medical device will have fewer parting lines or seams. Not only is the lack of parting lines on reaction injection molded parts advantageous aesthetically, but it can also prove valuable from a sanitary standpoint.

When there are fewer seams and parting lines in a part mean, there are fewer opportunities for dirt, dust, and other unwanted pollutants to accumulate. Therefore, medical devices produced with reaction injection molding (RIM) are easier to clean and likely more sanitary than devices made with other production methods lacking such molding capabilities. In an industry where cleanliness is mandated at all times, the absence of seams and parting lines where dirt and dust can collect is noteworthy.

Reaction injection molding is essential for medical devices due to its precision, durability, and ability to use advanced materials that meet stringent medical standards. Working with professionals ensures access to top-tier technology and expertise, delivering devices that are not only innovative but also safe and reliable for patient care.

If you are interested in implementing reaction injection molding as the manufacturing process for your medical device project, Rimnetics can help. We are the premier reaction injection molding company for cosmetic housings, encapsulation, structural enclosures, and overmolding in North America. For over three decades, we have provided the highest quality reaction injection molding services for medical devices. Our extensive experience and expertise in the field of RIM molding have enabled us to contribute to the success of thousands of projects. To gain more insight on how Rimnetics can help you create large, complex medical device equipment with design freedom at the lowest possible price, contact us today.

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