Numerous Considerations when Molding for MedTech
Jim Ritzema, director of operations and technology at Rogan Corporation, was a part of the staff written article, “Molders Address Biggest Device Issues.” He took time to present a full array of responses that were not able to be included in the article, so they are presented here.
Q: How can medical molders help device designers achieve compliance with the upcoming UDI rule?
Ritzema: Molders have several ways to help device manufacturers meet UDI requirements. In-mold decorating capability can make the unique identifying code and any necessary part identification codes an integral part of the component. Permanent engraving of the code into the tool steel can achieve the same result more cost-effectively than in-mold decorating, as long as the component is to be used in one device and not in multiple devices. Another possible option is a removable engraved tool steel insert.
Q: What features are most important to device designers to achieve through molding material selection?
Ritzema: It is essential that molded medical device parts be biocompatible, including being hypoallergenic and hygienic, giving bacteria and fungi little chance to grow and spread, and bioabsorbable where applicable.
Medical device/instrumentation parts also need to be capable of withstanding sterilization by multiple methods (including autoclave, Ethyl Oxide, and Gamma radiation) as well as interactions with chemicals, solvents and other cleaning agents.
Devices should be molded of durable material(s), to provide long working life of instruments for the patient, and should be designed to maximize patient comfort and safety. They should also be ergonomic and comfortable to use, both for medical personnel working with them in medical settings and for patients using them in home healthcare settings.
Device designers also need to consider the environmental impact and sustainability of the device, both during its usage life and beyond.
For efficient manufacturability, it is important that device components be consolidated as much as possible. For example, using two-shot molding of multi-component parts will reduce both the total manufacturing cost and the device assembly time. Also, using insert molding, Liquid Silicone Rubber (LSR) O-rings and gaskets can be molded directly onto the metal or plastic part they will be protecting, reducing both inventory and assembly costs.
Q: How are the capabilities realized through micro-molding changing medical device design?
Ritzema: The growing trend toward miniaturization of medical devices to make them less invasive will increase, and will require extremely precise micro-molding from injection molders. This allows for smaller parts and therefore smaller devices, and–especially important in the case of home healthcare external devices––greater portability and patient convenience.
Miniaturization of parts also facilitates the creation of internal diagnostic devices such as capsule cameras capable of relaying visual diagnostic data from within a patient’s body. These devices can eliminate more invasive diagnostic procedures or exploratory surgeries.
In both instances, miniaturization increases patient comfort.
Q: What type of molding technique is gaining more interest with molding device engineers?
Ritzema: One of the most important new molding techniques is the increased use of bondable LSR. LSR is biocompatible and hypoallergenic, resulting in minimal risk of allergic reaction during its use; and hygienic, reducing the chance of bacterial and fungal growth. These properties make it ideal for use in implantable medical devices.
LSR is flexible, durable, transparent, and UV and color resistant, and can withstand extreme temperatures, from −55 to +200 C, without change to its properties. It also offers superior compression set and the capability to be molded with varying wall thicknesses within the same part. These characteristics, together with its durability and flexibility, have led to LSR becoming critical in the development of components for medical devices.
Bondable LSR allows the molder to adhere a silicone rubber element to a metal, plastic, glass, ceramic, silicone-glass laminate or other silicone rubber part. Rogan Corporation has been a leader in using bondable LSR in molding operations, and has developed the most effective bonding procedures, which depend on meeting exact material and engineering requirements for each application.
The growing use of automation in molding operations helps to eliminate labor and unnecessary handling, resulting in more competitive manufacturing, better traceability, and enhanced sterilization.
In-mold decorating is also increasing. This process enables the molder to make branding and serial identification information an integral part of the molded part, which not only eliminates the possibility of the information becoming separated from the part, but also gives the finished part a more aesthetic appearance.
Two-shot molding also increases the integration of a part, consolidating what would traditionally have been two parts into a single unit. This not only saves assembly cost and time for the manufacturer, but also eliminates the possibility of the parts not being fitted together tightly during assembly.
Q: How are molders addressing the movement to more patient-based devices?
Ritzema: The strong growth of the home healthcare market has created a need for more patient-based medical devices. Rogan is meeting this need by collaborating closely with device designers to make devices less expensive, smaller and lighter (and therefore more convenient for the patient to use) and to get them to market as quickly as possible to meet the expanding need. Molders are also employing quick prototyping techniques to help reduce the development time of a new part.
Many molders are also buying smaller, more precise molding equipment that uses simulation techniques (such as mold flow analysis) that enables them to produce better components more quickly and cost-effectively.
Q: How are material advances impacting the capabilities offered with implantable devices?
Ritzema: One of the most significant advances has been the increased use of silicone molding. The general properties of LSR––the ability to be molded into complex shapes and sizes, and its inert chemical nature, not reacting to surrounding substances––make it an ideal candidate for use in medical devices.
For medical applications, the silicone must be medical grade, tested for biocompatibility and able to meet the necessary FDA requirements. Medical silicone applications are divided into two classes: restricted (for short-term implantable use) and unrestricted (for long-term implantable use).
In addition to being inert, LSR is also biocompatible, hypoallergenic, and hygienic. It offers superior compression set, can be molded with variable wall thicknesses in the same part and can successfully mold very complex geometries.
Advances in bioabsorbable polymers are also affecting the development of new medical devices. Degradation of a bioabsorbable polymeric implant, for instance, means that surgical intervention may not be required in order to remove the implant at the end of its functional life, eliminating the need for a second surgery.
Q: Where is medical molding headed over the next five to ten years?
Ritzema: The medical device industry segment is projected to grow at a greater rate than the US Gross Domestic Product (GDP) over the coming five to ten years. That growth will create more competition within the molding industry, and that competition, added to the growing pressure to reduce medical costs, will lead to an emphasis on reducing costs. One caveat to all these projections, however, is that the effects of the Affordable Care Act on the industry are unknown, and may limit that growth.
Growing concern about the safety of medical devices is driving moves by both manufacturers and molders to bring offshore operations and material purchases back to the U.S. While that may temporarily increase manufacturing costs, reduced exposure to recalls and other safety-related costs, including lawsuits, should more than offset that increase.
The coming years will continue to see an increase in the miniaturization of medical devices and consequently on the ability of molders to create smaller and more precise parts. Molders are also increasingly providing more design and engineering support to customers, as well as doing more assembly work and other value adding activities, delivering assembled modules rather than single parts to manufacturers. These shifts benefit manufacturers, by speeding production of finished devices, and will continue in the future.
Q: Any thoughts/comments on molding or another related area that you would like to share with medical device manufacturers to aid them?
Ritzema: It is essential for a manufacturer of medical devices to choose as a partner an experienced molder that is responsive and proactive in product development. Being able to work together closely in the early stages of the development of a device will save valuable manufacturing time later on and will also shorten the time to market for the device.