When Additive Manufacturing/3D Printing was introduced to the market, it was called rapid prototyping, which was an accurate description of the process – a method to quickly create physical prototypes from virtual representations of a product. The name has evolved over the years to additive manufacturing (AM) to capture the goal of the industry to create functional components in a more agile manner rapidly. This is the stated goal of the AM industry, but few have developed robust additive manufacturing production systems.
For traditional manufacturing production, quality and verification processes are in place to certify and qualify the material, manufacturing process, and end components. Materials are generally produced in bulk form and qualified by material sampling. Manufacturing processes, including cutting, molding, stamping, and finishing, are then qualified using a combination of machine monitoring and inspection systems. Finally, quality processes are put in place to verify the final components meet all required specifications. For additive manufacturing, the industry, in many ways, is still learning how to fit a new manufacturing process into an established manufacturing ecosystem. Below are three areas where the overall industry, including equipment manufacturers, material suppliers, and end-users, can work together to move additive manufacturing from prototyping to production.
"Material and process qualification is simply a means to the end goal of a functional component or system"
1) Qualify the Material
Many AM systems are open-material systems that can use a variety of material systems. In reality, these open material systems are usually relegated to prototyping. At the other end of the spectrum, machine vendors qualify certain materials for their systems and ensure the materials meet specifications. These materials are much more expensive than open-material systems, but they come with reliable batch data on the material quality. Even with this data, many companies will still conduct their own material qualification effort. In addition to qualifying the materials, how the material is stored, the age of the material batch, and the processing parameters used during the build all affect the material properties. A streamlined and robust material qualification process for additive manufacturing will be required for production applications.
2) Qualify the Process
For many manufacturing processes, it is a series of discrete processes that produce the end component. For example, the bulk material is cut down, machined, finished, and painted. Each processing step can be monitored and qualified. For AM, it is more of a continuous process that can present some advantages but also complications. Machine vendor qualified material to soften come with processing recipes for the material that is dependent on a variety of part geometry, machine parameter, and environmental factors to produce parts with consistent material properties. In some cases, the machine parameter settings such as power, path speed, and path trajectory are proprietary to the machine vendor, so the user must trust that the process will yield a component that meets specifications. One of the advantages touted by the AM industry is the ability to change material properties by varying the process selectively. We have yet to figure out how to qualify such material property variable components.
3) Qualify the Component
In the end, users want to end components that meet the required specifications. Material and process qualification is simply a means to the end goal of a functional component or system. Here, many of the traditional quality systems for checking dimensional tolerances, surface finish, and internal material consistency are adequate. AM component qualification processes are sometimes more stringent since the process is relatively new to many companies. As the industry gains more confidence in AM, these processes will become less expensive and more streamlined.
For many in the AM industry, the focus is on developing and selling machines, developing and selling materials, or selling end components. To move the entire industry from prototyping to production, all of the various players will need to work more closely together. As an example, Hexcel focused first on qualifying the material, then qualifying the process, and finally producing final parts that are flying and qualified on several aerospace programs. In this case, Hexcel is in charge of each part of the process from materials, to process, to end components so all can be coordinated and traced. Where these functions are done separately, the supply chain will be required to work together to achieve the quality to which we have become accustomed to traditional manufacturing. Companies that have been successful with production applications have treated Additive Manufacturing as any new manufacturing process and have developed quality procedures that conform with the overall quality system they have developed and established for all of the components and systems they produce. The key to accelerating the move from prototyping to production is treating additive manufacturing as any other manufacturing process and integrating it with the overall manufacturing production systems in place today.