The following sequence of steps is one example of the process:
- Device Design: A design is created and validated using digital models with pre-specified sizes or digital models matched to a patient’s anatomy.
- Software Workflow: The digital device design is converted to a buildable file that is sent to the printer. This file will often divide the design into layers, include additional support material to aid printing, and tell the printer where to build the device on the printer platform to prepare it for printing. The 3D printer often also requires some preparation to build different designs by changing settings for the material, type of design, and intended use.
- Material Controls: Like any manufacturing process, 3D printing needs high quality materials that meet consistent specifications to build consistent high quality devices. To ensure this, procedures, requirements, and agreements called material controls are established between the suppliers, purchasers, and end-users of the material.
- Printing: The object is printed using the design specifications included in the file.
- Post-Processing: After printing is complete, one or more post-processing steps may be performed on the device or component. These may include cleaning to remove residual debris, controlled cooling (also called annealing), and/or additional steps such as drilling, cutting, polishing, and sterilization.
- Process Validation and Verification: Some device or component characteristics can be checked individually after they are produced to make sure they will function properly and meet specifications. This is especially true of geometric features which can be checked quickly and nondestructively. Other functional specifications, like mechanical strength, cannot be checked on every individual production unit because the test could destroy the object or is impractical. To ensure devices meet these specifications, validation of processes occurs before production begins. Process validation ensures that a manufacturing process will produce product that is within defined specifications if specified processing parameters are monitored and controlled.
- Testing: Device testing is submitted to the FDA to show that it meets regulatory requirements and is reasonably safe and effective for its intended use. During production, samples may be tested to ensure that quality is being maintained. Each device or type of device has its own set of tests that may be based on FDA Guidance documents, international standards or internal process controls. Devices manufactured by 3D printing are generally subject to the same regulatory requirements as non-3D printed devices.
This flow-chart is a simple example of one possible 3D printing manufacturing process. Other possible processes may have different steps or additional branches. The Technical Considerations for Additive Manufactured Devices Draft Guidance describes each step in more detail.
Materials used in Devices
FDA does not typically clear or approve materials for general use in manufacture of medical device. For example, the FDA has approved spinal implants made from titanium alloy, but the FDA has not given blanket approval for the medical use of titanium. Materials used in formulating or constructing medical products are evaluated within the context of FDA’s evaluation of the safety and effectiveness of the medical product for its intended use. For additional information about how the FDA regulates medical devices, see Overview of Medical Device Regulation.