A validated workflow is a complete process, start-to-finish, for consistently producing safe parts that are compliant with the stringent standards that are set for medical devices. Validated workflows are more than just printing parameters.
A common myth is that if a resin is biocompatible in a liquid state, then it is suitable for producing medical devices. However, this couldn’t be further from the truth.
Resins in a liquid state are highly hazardous to human health and the environment as shown in their respective MSDS. However, if cured correctly as shown in the instructions for use (IFU) by the manufacturer and with the correct printing parameters and post processing protocol, they are able to produce biocompatible parts. At the end of the day, it is the printing and post curing processes that qualify a medical device.
Procedure for a validated workflow
Therefore, the following steps are required for a validated workflow:
- Curing time for the resin;
- Shrinkage calibration for the resin to produce geometrically accurate parts;
- Definition of the cleaning liquid and optimal cleaning time and process;
- Post curing time and requirements of nitrogen or not; and
- Post finishing instructions if any.
Typical FDA and CE regulatory bodies in the US and EU respectively have defined safety standards for 3D printing resins and therefore the workflow requirements. A validated workflow is then an assurance to the user of the printer and the resin being safe and compliant with regulations.