Many medical devices, including surgical tools, cutting templates, trial devices, and long term implants, are produced using additive manufacturing technology via the powder bed fusion (PBF) process. PBF offers a significant benefit in medical device production by enabling the creation of highly customized and patient-specific solutions.
PBF in Medical Device Manufacture
However, this unique manufacturing process has features that require specific characterization to ensure safety and biocompatibility. PBF often results in residual powder, which is hard to remove even with the use of post processing. Powdered material on the finished device could have clinical significance depending on the quantity of powder and anatomical location of the device.
The surface texture of PBF parts can vary greatly, ranging from rough and porous to smooth and dense. The surface finish can have a significant impact on the biocompatibility and the performance of the device. Additionally, the surface finish can affect the wear characteristics and potential for corrosion or delamination. Surface characterization of the PBF process is essential to ensure the safety and efficacy of the device.
ASTM Standards for Medical Devices Made by Additive Manufacturing
ASTM is working on standards to assess residual powder on medical devices. ASTM F3335 (Standard guide for assessing the removal of residues from medical devices made by powder bed fusion) has been available for a few years. ASTM is working on a supplementary test method standard for assessing residual powder (working item WK82776).
Another standard released by ASTM is F3456, which outlines how AM manufactures will reuse unused powder so they can report this process to regulators. ASTM is also working on a guide for material process validation in AM manufactured parts (WK72659).
These standards will help ensure the safety and efficacy of AM manufactured medical devices and provide guidance for manufacturers. This guidance is critical for the development and commercialization of AM-manufactured medical devices.