Constantly evolving, the medical industry requires OEMs to be forward-thinking in providing solutions that address trends and challenges. One such OEM, Smiths Medical, sought to change the design of its existing pulse oximetry portfolio to include enhanced functionality and improved manufacturability. At the project’s inception, they partnered with the U.S.-based injection molding experts at Kaysun to help refine and ultimately accomplish their goals.

With the freedom to create new features and cost-effectively achieve process efficiencies, it's obvious why many design engineers prefer to use complex injection molding to create plastic parts and components.

What isn’t always clear, however, is the myriad considerations required at the onset of the process. Among them is selecting the appropriate materials to make the actual mold as well as plastic injection molding materials for the part. Here are key points to keep in mind when working through it with an injection molder partner.

Complex injection molding is a viable solution for many projects, but there’s often hesitation in using it because of confusion about which material matches the job. While “thermoplastic” and “thermoset” sound similar and both are appropriate for a wide range of applications, the material properties of these two resin categories and how they behave during processing ultimately reveal the best fit.

Manufacturers of rugged electronic devices (and their end users—for example, the military) count on their “rugged” devices to perform in challenging real-life conditions, and survive being dropped. Therefore impact resistance is a critical feature in product design and starts with material selection.

Many industries can take advantage of antimicrobial resins. Examples where these resins are most commonly used include water-treatment systems, food packaging, plumbing and HVAC, medical/diagnostic equiptment, dental implants and personal care products. They are also utilized in clean room sensitive electronics testing and assembly, sterile packaging, conveyers, public transportation, and office equiptment.

Surface finish on plastic composites can vary a great deal, depending on the physical and chemical properties of the polymer blend, as well as the parameters of the injection molding process.

The first objective is working with the client to determine how important the surface finish is for the appearance and/or performance of the final product. For example, does the product need to be eye-catching or simply functional? Depending on the answer, the material selected and the desired finish will determine the settings for the injection molding process, as well as any secondary finishing operations that might be required.

Commodity plastics are versatile materials appropriate for a breadth of applications. However, specialty or complex injection molded parts like those required for medical, fire, and safety industries may contain requirements that mainstream polymers can’t fulfill, such as chemical resistance, fire retardant properties and mechanical grade strength.

Controlling costs is a huge part of any project. Materials can be expensive, especially advanced or specially-engineered resins, so you want to get as much bang for your materials buck as you can. One way to do this is the proper use of regrind.

There is always some unused thermoplastic material that is left over from injection molding, typically taken from mold components such as gates, flash, runners, and sprues. What's the point in wasting it.

Critical-use medical devices are essential in the performance of important and often life-saving tasks. As such, they often boast complicated designs and functionality that require the expertise of a complex injection molder to produce. However, that’s only part of the equation.