Overmolding in the Medical Device Industry

2026-07-17

Creating medical devices for a wide variety of applications often requires the use of a manufacturing method that allows you to insert a component into the molded part. Doing so offers several benefits such as improved sanitation, reduced risk of intellectual property theft, and increased part strength. Reaction injection molding is one of the most effective manufacturing methods for encapsulating materials without harming sensitive components often included in medical devices. For more information regarding encapsulating and overmolding in the medical device industry, consult this comprehensive guide.

DIFFERENT METHODS FOR MEDICAL INSERT MOLDING

When designing parts, there are many different ways you can insert an item inside. Three of the most used methods for molding items into products include medical overmolding, potting, and encapsulation. At Rimnetics, we focus on encapsulation and overmolding. While many people view encapsulation, potting, and overmolding as synonymous processes, they have slight yet distinct differences that set them apart from one another; you should consider these when choosing a part molding process. Below, we will discuss how each of these processes differ.

HOW ENCAPSULATION IS DIFFERENT FROM THE POTTING AND OVERMOLDING PROCESSES

Potting Potting is a commonly used manufacturing process that involves submerging or concealing an electronic assembly into a part using a compound material. During this process, the shell that is filled with resin ultimately becomes a part of the completed component.

Overmolding The Overmolding is a process which involves seamlessly molding one or more materials into another material to form a single part. In most cases, the substrate is fully covered by the overmold materials during the process.

Encapsulation Encapsulation involves coating or entrapping a component or material within the molded resin. Unlike potting, the component and hardened resin are ultimately removed from the mold. A shell is not needed.

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THE VALUE OF ENCAPSULATING AN ITEM INTO A RIM PART

Reaction injection molding in the medical device industry provides a unique opportunity to encapsulate parts. Encapsulation is only possible with reaction injection-molded parts because of the lower temperature and pressure in the RIM process. Such low pressures and temperatures of the polyurethane molding resin allow items to be encapsulated without harming their interior components. Even sensitive items such as circuit boards, batteries, and antennas can be encapsulated in reaction injection molded parts while maintaining the same level of functionality.

In addition to the low temperature and pressure that reaction injection molding occurs at, it is also worth mentioning RIM’s low viscosity in relation to its encapsulation abilities. When you use other common molding processes such as injection molding, a paste with a thick consistency similar to that of peanut butter is injected into a mold. Because reaction injection molding involves injecting a liquid with a consistency similar to motor oil, without damage, wear, and tear is inflicted on the items being encapsulated.

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BENEFITS OF ENCAPSULATING OR OVERMOLDING

There are many instances where overmolding or encapsulating an item into a part is highly beneficial to the medical device industry.

Molding and Sanitation To avoid crevasses that can create an unsanitary situation, manufacturers can overmold or encapsulate magnets that can hold the door closed directly into the part, minimizing seams and grooves where germs collect.

Encapsulation for Wireless Applications It makes it possible to mold antennas into parts. As a result, medical devices can become wireless which can greatly expand their applications.

Increased Encapsulated Part Strength By encapsulating hinges or items that help connect one part to another part, you can increase the strength of the product and create a more durable medical device.

Protection From Harsh Environments Items are virtually impossible to break inside the part, which allows the machinery to operate in rugged environments where water, vibration, chemicals, and extreme temperatures are present.

Protection From Intellectual Property Theft By being molded into the machinery, items are much less likely to become stolen. The risk of intellectual property theft is greatly reduced—if not completely eliminated.

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Summary

This article mainly introduces three common insert molding technologies for medical devices: overmolding, potting and encapsulation, and clarifies their key differences. It highlights Reaction injection molding (RIM) as an ideal solution for medical encapsulation due to its low-temperature and low-pressure conditions.

Four major benefits are illustrated: improved sanitation, wireless capability via internal antennas, increased structural durability, and protection against harsh environments and intellectual property theft.

At ABBYLEE, we are injection molding specialists, ready to share our expertise with you. Our engineers have a deep understanding of injection molding best practices, and we incorporate them into our services. We provide free DFM to ensure that you have the best results from your part design.

Our wide range of manufacturing services includes robust injection molding services. We offer general inspection of parts to ensure they are ready for the molding process at competitive prices.

For more about what is undercut in injection molding, you can pay a visit to ABBYLEE at https://www.xmabbylee.com/plastic-injection-molding-parts/ for more info.