Renishaw
AM jaw implants.
The ever-changing world of manufacturing has seen drastic changes throughout the years. New technologies are introduced to help improve productivity, reliability, or the safety of manufacturing products, and are then outcasted when the next shiny new toy comes along.
John Laureto, Business Manager at Renishaw, has outlined the role metal additive manufacturing (AM) processes can have within the medical industry. To ensure manufacturing processes are safe, effective, and able to produce the intended product, solutions must pass process qualification expectations. Due to the nature of the medical industry, these processes are even more important, resulting in the creation of regulatory bodies like the Food and Drug Administration (FDA) and the Medical Device Regulation (MDR) that exist to produce process qualification frameworks.
“Medical manufacturers were early adopters of AM to develop patient-specific parts with complex geometries at low volume,” said Laureto. “As AM technology develops, more medical manufacturers are considering how they can now implement it into mass manufacturing.”
In cases where validated processes are already in place for manufacturing parts, manufacturers can evaluate where AM could benefit from the process. Alternatively, they can also seek the advice of AM experts to understand how AM can boost quality assurance levels.
Understanding AM in the medical industry
There are three protocols that will help determine whether the equipment has been installed correctly and will perform as expected. These are Installation Qualification (IQ), Operation Qualification (OQ), and Process Qualification (PQ).
- IQ: The system supplier and end user must verify the equipment has been installed according to the manufacturer’s specifications. This is key to ensuring the machine will perform as the user expects. Concerning AM, a power map test, scan field correction, beam focus, and beam profile tests will all be conducted.
- OQ: Once the system is fully calibrated, the system supplier will then train the end user on how to operate the platform as detailed by the OQ documentation. Also, builds may be manufactured and validated with empirical evidence either by mechanical testing or checking dimensional accuracy.
- PQ: Finally, once the machine has been installed correctly and has passed these checks, manufacturers can start documenting the PQ. This may include manufacturing cycles with products related to the application area.
Barriers to adoption
Adopting new processes, especially using new technologies, is very challenging, especially in highly regulated industries. Specifically looking at medical manufacturers, when AM has been used to produce specific parts, intellectual property (IP) can prevent qualification information from being released. However, as the adoption of AM increases, this may be less of a problem.
“Similar to casting or classical welding, the resultant microstructure in the parts produced using AM is dependent on the raw material feedstock, laser parameters (process variables) and part geometry,” said Laureto. “Thus, the necessity for a rigorous PQ as the bounds of this resultant microstructure must be fully understood for a particular product category. It is reasonable to expect the microstructure in the lattice structure of a spinal implant to vary to its similar material counterpart in a tibial tray for orthopaedic applications.”
The catalogue and design rules around AM are still developing, which in turn will improve confidence levels when implementing these solutions in the manufacturing process. During the validation process, parameters outside the machine can also influence the final part's integrity.
Although the qualification of AM processes is challenging within the medical device industry, once granted authorisation by a regulatory body a framework is established that can be used in the future. Additionally, when changes to part design occur, the original process can be adapted a lot quicker, while changing AM systems or investing in additional solutions can be easier, especially when purchased from the same supplier.
AM has progressed out of the realm of research and development, now manufacturers are embracing new technologies with AM as users have greater knowledge than ever before. As users continue to understand how effective the technology is, adoption will become easier and more popular. AM solutions can help manufacturers validate processes and aid with the mass production of quality parts that will go on to improve patient outcomes.