Plastic Injection Molding And Biomechanics

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The area of biomechanics has produced some of the most incredible technological advances of any industry. Just naming a few — prosthetic limbs, internal implants, accessibility-improving wearables and more — sheds light on the innovation that goes into these quality-of-life-improving and, often, life-saving creations. What’s more, biomechanics continues to advance, as next-generation fields such as artificial intelligence and nanotechnology reach maturity and become increasingly integrated into these types of devices. Not to be left out of the technology supporting biomechanics is plastic injection molding — which either supports or provides the basis for a huge range of biomechanical devices, particularly prosthetics.

Below, we’ll examine the role of injection molding in biomechanics, including a look at some of the more specific types of injection molding that play a part. Then, we’ll cover some of the benefits that injection molding provides.

Different Types of Injection Molding for Biomechanics

As a versatile and readily available process, injection molding is an ideal choice for many aspects of biomechanical devices and fabrications. Injection molding in general is a cost-effective, fast way of creating a broad range of pieces, parts and constructions — large or small. Two of the more specific applications of injection molding are especially well-suited to biomechanics:

  1. Overmolding: Overmolding is the method of molding a new shape around an existing piece. The existing piece might be another injection molded part, or it may be something created through a different means — CNC machining or 3D printing, for example. Given the complexity and importance of precision in biometrics, overmolding plays a critical role in creating tight-tolerance, multipiece components such as a metal support rod within an injection molded prosthetic piece.

Overmolding makes production easier by integrating a production and an assembly step, and reduces the margin of error that exists when assembly is done separately.

  1. Micromolding: Micromolding is, as the name implies, the practice of molding parts at an extremely tiny level — often not visible to the naked eye. Micromolding is a distinct process from injection molding, though it is based on the same principles. The extremely high precision and delicacy of micromolded parts is what sets them apart. In biomechanics and prosthetics, micromolded parts may facilitate motion, fit, attachment or adherence — internal functions necessary to make the part operate properly and more. Micromolding is an area that continues to advance and, as it does, enhances the potential of biomechanics.

Importance of 3D Printing

Before moving on, it’s worth pausing to note the importance of 3D printing in biometrics, especially as related to injection molding. While 3D printed parts can play an independent role in functioning prosthetics, the process can also support many aspects of injection molding. 3D printed prototypes allow for faster, more nimble part and component design and iteration — providing immense benefits in the innovation area as well as the ability to customize pieces. As mentioned earlier, 3D printed components can also be the core element in overmolded assemblies. Plus, the advances in 3D printing processes and materials mean that not only are working 3D printed components a reality for prosthetics, but that 3D printed prosthetics themselves are also possible.

Specific Ways Injection Molded Parts Play a Role in Biomechanics

Focusing back on injection molding, we’ll close by discussing some of the specific benefits and applications that the process brings to biomechanics and prosthetics:

  1. Range of materials: A wide range of materials are available for injection molding, bringing with them an extremely broad and customizable range of material properties. As a further benefit — the “core” set of commonly available and used injection molding resins covers a vast part of the material properties that may be required for a prosthetic. For instance, plastic injection molding is able to easily produce parts, pieces and components that are both extremely strong and highly flexible, using readily available materials. This makes production that much easier, keeps costs down, and increases access to these important products.
  2. Biosuitability: As a further benefit of material diversity and availability — many injection molding resins are readily able to be used as biomechanical components, meaning that they won’t adversely interact with the internal and external parts of the human body with which they come into contact. This is a critical factor for any material that will be used in a prosthetic, even for factors as simple as preventing skin irritation or reaction.
  3. Ability to formulate materials for different needs: One more important point about injection molding resins: they’re able to be easily combined and fine-tuned to achieve the necessary material properties. For example, rather than tracking an exotic material or creating one from scratch in a laboratory, many resins can be combined to enhance or alleviate certain properties. This allows prosthetic parts to meet even more specific needs. Not every resin can be combined with every other one, but an injection molding service provider can be a valuable guide in areas where this is required.
  4. Ease of prototyping and manufacture: Injection molding is a broadly available and widely used manufacturing process. Thus, there’s no price premium for creating biomechanics and prosthetics through this means. While certain aspects of the technology that go into prosthetics are, indeed, more highly customized and specialized, the relatively ready availability of injection molding facilities makes it that much easier to complete these complex assemblies. In addition, prototyping through 3D printing — a widespread technology — can easily replicate many qualities of injection molding resins.
  5. Customization: Injection molding is a highly versatile process, with extremely complex, precision parts able to be produced via the same general method as simpler shapes. The level of precision and customization that can be achieved with relatively little adjustment to the process itself means that injection molding can meet the needs of a broad cross-section of biomechanical parts, components and constructions, for a wide range of needs and individuals. Highly customized assemblies can be produced using molding methods like 3D printed molds. One-off or low-run pieces can even be created specifically for an individual, right out of the mold — a benefit that often isn’t possible with other processes, where secondary customization and finishing would be required.

We’re ready to answer any additional questions you may have about injection molding and biomechanics — contact RevPart today.

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