The Challenge Residue Removal Assembly (CRRA) is a research tool designed by OSEL FDA researchers to mimic medical devices, namely orthopaedic, to evaluate challenges in removing additive manufacturing residual materials from porous geometries. The CRRA is a disc assembly composed of a circular base and wedges that slide onto it. The alternating openings on the base create variations in porosity coverage (blind and through porosity) on individual wedges.

A ten-millimeter tall blank version of the CRRA is provided. The volumes of the wedges are provided as solid blanks, so that users can modify them with their own porous structures. Two use scenarios have been identified, although the flexibility of the CRRA and further use may help identify more:

• CRRA with six (6) identical wedges: n=3 samples of identical porosity with blind or through samples in a single disc
• CRRA with three different pairs of wedges: n=1 per combination of porosity/coverage (3 porosity designs)

The CRRA was designed for production with a specific polymer powder bed fusion system (PBF). Changes to clearances between wedges, and at the locking/sliding mechanism may be necessary for ease of production and assembly with other PBF systems, or other additive manufacturing processes.

This challenge assembly, its components, and framework are for illustration purposes only, the end user should adapt them to fit their needs.  They do not represent a definitive challenge or test for any specific medical device.