You have your next idea already in the works, and it’s time to finalize the design to create plastic injection molding tools. Have you thought of everything and identified the correct resin for your medical device? If you have a designer and expert that currently supports the medical industry handling the choice, they should be able to identify the best resin available to use. If you’re making the choice, here are the criteria that you should be considering to narrow the focus:
Strength Requirements
Medical devices can range from simple items used in your hands, to complicated machines used in procedures in an operating room. Your new product needs to withstand the situations its planned to encounter. If it is a hand-held device, that may mean it needs to have strength and durability to withstand a drop from 3 feet onto a hard surface. If your device will be used on a stand, it may also need to have the ability to handle impacts, or the ability to handle surface wear if used by a traveling healthcare worker. Be sure to identify the strength and durability requirements of for your product, and select a resin that will easily handle the situation.
Environment
Medical devices are used in harsh environments that require constant disinfection and sterilization with chemicals. The device may also be exposed to oils, grease, and other lubricants when it is used in a medical procedure. Knowing the environment your new medical device will be used in will help to narrow the focus on the resin to choose. Other factors of heat, cold, and extreme humidity in the surrounding environment, electrical discharge and conductivity, and other forms of sterilization may need to be considered when selecting a resin also.
Part Design
Part design can cover a wide array of topics from materials used, dimensions, tolerances, drafting angles, to material flow inside the mold, and finished product characteristics. When you’re discussing medical devices, another topic of antimicrobial surfaces needs to be included. Antimicrobial agents, such as ionic silver, can be included in your new medical device to provide microbe-resistant surfaces that will eliminate bacteria growth.
Coloring
If your new medical device requires a coloring, you may have to decide how the natural resin color is changed. There are options for a resin colored from the resin supplier, or the injection molder may be able to blend a color concentrate into a clear resin to make the final color. A point of your design criteria also should note if off-color parts are acceptable for the final product. Color variations can happen in injection molding, and you may or may not need to have strict color shading for the final product.
Overmolding
Your new product may have a handle that needs to contain a rubber surface to make it ergonomically suitable for continued use. In that case, an overmolded secondary layer of rubber can be molded over a plastic base. You have the ability to choose a different color to make it visually pleasing to your customer, and overmolding doesn’t increase the cost significantly if incorporated ahead of time.
Metal Replacements
Your new product may not be a new design, but more of a revision of an aging device currently on the market. Fifty years ago metal was the go-to standard for medical devices. With the increase in technology and available spectrum of excellent resin choices, you may just be revising the design of an older metal device. One advantage to doing a redesign is that you currently have a baseline product that identifies the criteria for performance of your new device. It should meet or exceed the functional performance of the metal device to be replaced.
Cost
The cost of a product will always have an influence on the design, and the resin selected for the injection molding. By adhering to a strict cost for manufacturing, you may find that some of your performance criteria may need to change, the tight tolerances you believed you had to have may need to be loosened up, or the secondary overmolding may need to be revised. Knowing the end cost to keep a specific profit margin allows you and your team to identify areas in the design process that won’t return the value needed to bring the new device to market.
One-Time Use or Re-Use
A consideration for your medical device may be if it is designed to be used once or sterilized over and over for re-use. A one-time product may be used quickly and then disposed of via waste or recycling. A multi-use use device may require sterilization via gamma radiation, steam, ETO (Ethylene Oxide), or autoclave. Each of those methods may require different resin characteristics to be heat tolerant without melting, or adding a chemical resistant exterior.
Implantation or Direct Fluid Contact
Your new medical device may need to be implanted, which will be continuously in contact with bodily fluids. That may also mean that it will need to be anti-static, static dissipative, or have EMI/RFI shielding properties to withstand X-Ray, CT and MRI scanning without degradation over time. If biocompatibility isn’t the end goal of your new device, it may just need to be resistant to direct fluid contact for a short period before it is sterilized or added to biohazard waste to be disposed of.
Secondary Labeling or Processes
Should your new medical device incorporate a secondary labeling or printing operation? Your selected resin should incorporate the option of adhering to labels as required, or offer a texture and surface for printing. Certain resins also perform better than others for secondary operations for assembly, including fasteners and heat staking.
Testing Requirements
One final item on your checklist will be testing required to prove your design is ready for the market. How and where your device will be used should indicate what testing is required for any certifications required by country of use, in what environment it will be used, and how it can be sterilized or recycled. If you are doing the testing, you have to provide all documentation to a certification organization before they sign off on your new device. If you need to obtain a 510(k) or CE mark, it may be a better option to let an expert handle the design and testing to certify your product.
When choosing a material for the development of your new medical product or device, there are many factors that need to be discussed for the resin selected. Expect that a medical device injection molding company will ask you many questions during the research and design phase of the project.
SEA-LECT Plastics is a leader in medical device plastic injection molding with additional options for assembly and logistics. We have experts that can aid with resin selection on a new product to increase recyclability and reduce waste, offer turn-key assembly options that reduce power requirements, and program management to see the complete development cycle through with success. Give us a call at (425) 339-0288 or email us at mattp@sealectplastics.mystagingwebsite.com. At SEA-LECT Plastics, we specialize in military product applications, outdoor adventure gear, musical instruments, supporting the medical and consumer product industries. Our goal is to make your project efficient and cost-effective to manufacture, assemble, and ship no matter how complicated your concept is.
Matthias Poischbeg was born and raised in Hamburg, Germany. Matt moved to Everett, Wash., after finishing his bachelor’s degree in business in 1995 to work for Sea-Dog Corporation, a manufacturer, and distributor of marine and rigging hardware established in 1923.
In 1999, Matt took over the reins at Sea-Lect Plastics Corporation, a sister company of Sea-Dog and a manufacturer of plastic injection molded products with an in-house tool & die shop. Matthias Poischbeg is also a contributor to Grit Daily.