To control product development costs without sacrificing quality, medical device OEMs are giving new life to their product development process by turning to aluminum extrusions instead of other more costly materials to manufacture their components.
Not only appropriate for tube-shaped profiles, aluminum extrusion is perfectly suited for a range of medical device component applications. The ease of extruding aluminum alloys makes the material ideal to form into virtually limitless shapes and sizes while adhering to sought-after precision tolerances. Designs can include a variety of specialty features, such as lap joints, dovetails, or hinges. These features help reduce manufacturing steps and ease assembly when mating with other components, ultimately reducing the cost to develop a medical device. (See Figure 1)
To give new life to their product development processes, OEMs need to understand the misconceptions and critical factors that affect component design before discounting the endless possibilities of designing with aluminum extrusions.
Misconceptions of Aluminum Extruded Products
OEMs may believe that stainless steel is a cleaner, more appropriate material for the medical market. But with proper finishing treatments, such as anodizing, aluminum extruded products can actually be less porous and cleaner than stainless steel. The inert chemical compounds in aluminum combined with proper finishing techniques help prevent corrosion and chemical absorption, which are keys to preventing contamination and easing the cleaning processes in medical care applications.
With its high strength-to-weight ratio, aluminum extrusion lends itself well to a range of medical product applications that OEMs can confidently rely on to replace steel components. As application temperatures drop, aluminum gets stronger, whereas steel and plastics get brittle and can break, making aluminum an ideal choice for low-temperature applications. Aluminum also is more than 60 percent lighter than steel, helping minimize overall load weight.
Aluminum Extrusion Critical Factors
Depending on the medical component application and function, surface cosmetics are one of the top factors to address when specifying aluminum extrusion services. Medical device OEMs need to determine their surface requirements, so the extruder can prepare for and maintain those critical features. Several factors, including alloy choice, design features, and handling of the final extrusion can affect surface finishes.
Alloy choice is important because different alloys have different flow and cooling requirements causing design features like wall thickness variation and adjoining structures to affect the appearance of critical surfaces. Educated extruders will know how the different alloys work and how to maintain the proper die bearing surfaces to create the desired result and prevent surface finish flaws. They will recommend the best alloy to use based on finishing needs, machining, and strength requirements for the product application.
Designers also need to determine which surface is non-critical and can bear run-out marks, as extrusions must be extruded onto a surface area. Product handling—from fabrication tooling fixtures to packaging—can also affect surface finishes. Because an anodic surface is harder than the raw aluminum surface, options like anodizing before machining might save costs in finishing and prevent handling marks. OEMs should seek extruders who understand their component needs to help address these critical factors.
Critical tolerances are another factor that OEMs need to consider when designing for extrusion. Medical manufacturers need to know and understand component tolerance specifications and how downstream processes, such as surface finishing and hard coat anodizing, can affect final tolerances. They need to finalize component designs by thinking through the manufacturing process backwards, beginning with assembly, finishing, and then machining, in that order, to gain a solid grasp on the best way to design and extrude a component for better manufacturability.
While aluminum complies with the European RoHS and REACH medical device guidelines and is 100 percent recyclable, manufacturing compliance is another critical factor for medical manufacturers. Even the slightest change in process or design variation can potentially require revalidation, increasing costs and delaying time to market. OEMs should work with an extruder who has in-depth knowledge of both regulatory requirements and process validation.
Similar to the evolution of electronic devices over the past few decades, medical devices are shrinking in size and weight to enhance portability, mobility, and handling. This transformation is pushing OEMs to find alternative ways to fit in more technology. There is value in considering using aluminum extrusions with smaller profiles to cut material costs, even if the original component was made from another material.
To make designers’ jobs easier, aluminum producers continue to create new alloys that can easily be extruded into thinner shapes, remain light in weight, and yet remain strong enough to withstand the everyday wear that is common in medical or at-home environments. On the other hand, designers need to ensure that their aluminum extruder is innovative, and has the capability and expertise to extrude these new alloys. Aluminum extrusion is an ideal material for use in the ever-changing medical device market based on its short-production cycle, low cost, and adaptability.
This article was written by Rodney Floding, Die Design/Extrusion Engineer, Alexandria Industries, Alexandria, MN. For more information, Click Here .