One of the most well-known benefits of additive manufacturing (AM) is the ability to integrate elaborate surface technologies. These technologies, such as lattices and gyroids, allow for improved bone adherence to the textured surfaces. However, these surfaces also pose new cleaning challenges. Traditional cleaning methods for devices produced via subtractive manufacturing must be modified to account for the added complexities and increased surface area of additively manufactured parts. Read more about these modified cleaning processes in the BONEZONE article, Cleaning Considerations for Additively Manufactured Parts.
Each AM medical device has unique features and validating the cleaning process for each device individually would be a tedious and high-cost endeavor. Instead, rms Company developed and validated a cleaning coupon which can be used for most AM parts we produce. The coupon was developed per ASTM document F33325-20 to replicate the “worst-case” features and processes that a typical AM device may include or require.
For this coupon, there are three unique surface technologies as well as numerous as-printed holes and slots. The coupons are removed from a build plate via EDM, exposed to a dielectric fluid, and then hot isostatic pressed through an external vendor. Once returned, the coupons have a threaded hole milled into them and are both glass bead and K-Burr blasted. These post processing steps expose the coupons to the typical materials that an AM device may come into contact with throughout its manufacturing lifecycle
On a quarterly basis, these coupons are cleaned, passivated, and tested for the presence of harmful materials such as total organic carbon, inorganic contaminants, and bacterial endotoxins per ISO and ASTM standards. The coupons are also sent out to Meter CT Scanning (now Lumafield) to verify the surface area to volume ratio. They can then be compared to other AM products using a challenge matrix. As long as these coupons have a higher risk score than the products they are challenged against, a unique cleaning validation is not required for each AM product we produce.
The creation of a cleaning coupon allows rms Company to save time and manage costs for our customers while meeting high quality standards.
