After losing four babies, Jamie McDonald was overjoyed to learn she was expecting twins. But her happiness abruptly ended when she gave birth to the tiny pair at 24 weeks. “We felt pretty positive we were never going to bring them home,” she recounted to “The Doctors” syndicated talk show.
 
McDonald’s babies—Everly and Maverick—weighed 1.9 pounds at birth and both were diagnosed with patent ductus arteriosus (PDA), a potentially life-threatening congenital heart condition triggered by an opening between two cardiac blood vessels. The sixth most common defect, PDA occurs in 5-10 percent of all children born with congenital heart disease, and is twice as likely to occur in girls than boys.
 
The condition is treatable with therapy, minimally-invasive catheter-based interventions, and minimally-invasive surgical solutions. Doctors chose the latter option for Everly and Maverick, implanting a pea-sized wire mesh device between their pulmonary arteries and aortas to prevent blood from mixing and straining their tiny hearts and lungs.
 
The device, made by Abbott Laboratories, is inserted through a small leg incision and guided to the afflicted cardiac vessels. Manufacturing such a diminutive object most certainly entailed micromolding, a type of injection molding that produces extremely tiny parts, often with micron tolerances. The process uses special equipment that can produce intricate designs and details.
 
Medical Product Outsourcing’s October feature, “Little Big Parts,” addresses the latest trends and challenges shaping the fast-growing medical micromolding market. Aaron Johnson, vice president of marketing and customer strategy at Accumold, was among the various experts interviewed for the story. His full input is provided in the following Q&A.
 
Michael Barbella: What are the latest innovations in micromolding technology? 
Aaron Johnson: At Accumold, our innovations are 100 percent driven by our customer’s needs. Lately our innovations have centered around high-velocity projects with high output, high quality demand at high speed. Our innovation team is constantly developing new tools that enable tooling and production to solve some very complex customer demands.
 
Barbella: What market forces are fueling the need for micromolding technology and services? 
Johnson: It sounds cliché but the miniaturization trend in technology has not slowed, especially if you think of what it means to medical device. Miniaturization is a key driver for adding more features and/or allowing for further formfactor reductions. This often translates into better diagnostics, faster recoveries, or overall better patience care.
 
Barbella: How is the need for smaller, more complex medical devices/components challenging micromolding suppliers and providers? 
Johnson: Every time the need for smaller, more complex components pushes the boundaries, it challenges the supply chain. It becomes a way of life. Micro molding suppliers should be ready to take on potential roadblocks and not dumb-down the part just to make it easier. Starting with the customer’s ideal is always goal number one.
 
Barbella: What factors must be taken into consideration in designing tooling for micromolded parts? 
Johnson: There is no easy answer when answering, “What are the guidelines?” When it comes to micro molding, each part design brings a unique set of challenges to the equation. One of the primary considerations in what we call, DfMM, Design for Micro Molding, is matching material selection and the part geometry. Understanding these relationships at the micro-level takes experience over what a data sheet might say.
 
Barbella: Should micromolding tooling design be outsourced? Why or why not? 
Johnson: In our opinion, no. If you are expecting microns in the outcome of the process in-house tooling is a must. Can you get good tooling on the outside? Absolutely. But we have found when working with a highly specialized process like micro molding, the pieces of the puzzle – tooling, processing, metrology, etc. – being vertically integrated leads to a faster and more robust process. Tooling is such a critical part of the success at this level it would be hard not to have full control.
 
Barbella: What material advancements are currently impacting micromolding capabilities? 
Johnson: With the advancements in miniaturization product designers are finding themselves looking for solutions that were once unnecessary. These pressures are asking for plastics to “live” in spaces they once stayed away from. For example, a common trend is wafer-level components. Designers would like plastic components to survive the solder-reflow process and other harsh environments during assembly and testing. In theory, these designs could add tremendous value, but it puts a lot of pressure on the material developers to formulate resins that match the needs.
 
Barbella: What are customers demanding or expecting in their micromolded products?
Johnson: There is an increasing demand these days for more value-added services. More and more OEMs are asking their supply chain to support processes like assembly, packaging and/or sterilization.
 
Barbella: How are minimally invasive and point-of-care applications affecting micromolded device design and development?
Johnson: Typically, in both minimally invasive and POC applications, the smaller the better. And since there are often other components involved, the pressure to reduce the plastic components is higher. Thinner wall sections, higher aspect ratios, and smaller features are commonly the way more room is made for new electronics or other functions.