Overcoming the Challenges of 3D Printing with Metals
3D printing is quickly catching fire in the world of manufacturing. Although the aerospace and medical-device industries were the first players to adopt the process, all industries that work with metals are now beginning to realize the promise of 3D printing, also known as additive manufacturing (AM). If there is a company that hasn’t yet begun to explore the technology – they should, says Jack Beuth, professor of mechanical engineering at Carnegie Mellon University (CMU).
“When it comes to additive manufacturing, the clock is ticking,” said Beuth, who specializes in process modeling and has been researching AM technology for over 20 years. “It is important to act quickly because those who understand and prepare for the coming changes in additive manufacturing will outcompete those who do not.”
Additive manufacturing has the potential to reduce waste, decrease time to market, increase product performance and promote product innovation. The layer-by-layer manufacturing technique radically changes product-development procedures and can be used both for prototyping and as the final process for part fabrication. But as with any budding technology, AM has challenges standing in its way on the path to becoming a mainstream manufacturing process. Companies are concerned that the technology needs big improvements in areas such as the build rate of parts, fatigue resistance of materials and customization of the process.
Researchers like Beuth and Anthony Rollett, materials science and engineering professor at CMU, are confident that these hurdles will quickly be cleared, creating new opportunities for industry.
“Over the next five years, there will be a major shift in perspective when it comes to AM technology,” Rollett said. “Right now, there is excitement around reimaging shapes or manufactured parts because we now have the ability to build them up layer by layer. However, the real excitement will come when companies are able to manipulate part design, powder feedstocks, process variables and post-processing simultaneously.”
The NextManufacturing Center, which Beuth and Rollett co-direct, has focused its attention on making this goal a reality and increasing widespread adoption of the technology. NextManufacturing Center researchers are currently working on research projects to overcome the current challenges in the field. The center is developing an entirely new approach to metal AM – merging data from all parts of the process to create a fully integrated understanding of the technology. Click here if you'd like an inside look at a 3D metal printer in action at Carnegie Mellon University.
In this issue of 3D Printing Report, we’ll explore challenges related to the AM process and how current research will enable advances in this area over the next five years.
Currently, direct-metal AM processes do not offer much customization to the user. Users are only able to control a narrow range of process variables such as beam power, travel speed, layer thickness and part temperature. Beuth points out that machine users need more control of the process in order to better manipulate the outcome.
“Users need to be able to design the AM process as they design the geometry of the part,” Beuth said. “This customization would allow companies to optimize the specific process variables that they need based on characteristics of the part they are printing.”
To fill this need, Beuth has developed a patent-pending technology that has the potential to revolutionize metal 3D-printing processes. This technology, called process mapping, can map out actual process outcomes like surface finish, microstructure and porosity. Using process mapping, companies can differentiate themselves from their competitors by creating their own proprietary processing “recipes,” which include specialized process characteristics. In the next five years, this process-mapping technology will allow the user to further customize the process as they customize the design of their part.
Monitoring and Control
AM processes are currently not significantly monitored. For example, users are often only able to monitor the overall temperature in the build chamber of their machine. They are not able to monitor the consistency of other integral parts of the process, such as the precision with which the powder is spread or the size of the melt pool. This is problematic because it means that users are getting very little data about their build and are therefore unable to easily identify or correct problems, such as incomplete powder fusion.
The NextManufacturing Center is working to both improve sensors and add new ones. In five years, machine users will be able to monitor and control the AM process, which means adjusting the printing process as a part is being built.
Mechanical properties such as strength are determined by the small-scale structure of metals known as microstructure. Currently, users are not able to vary the microstructure in different locations of an additively manufactured part. Beuth explains that this will soon change, giving engineers new tools to optimize part performance. It’s an advancement, in fact, that Beuth and his research team have begun to realize just this year. Beuth’s team recently demonstrated the ability to control key aspects of microstructure for two different types of additive processes and two different metals. Their techniques are advancing rapidly and are now being transferred to industrial members of the NextManufacturing Center.
Within five years, users will be able to vary the material microstructure and properties in different locations of a part by manipulating process variables as a part is being built.
Metal Powders, Controlling Porosity, Machine Learning and More
Keep your eyes peeled for part two of this article in the December issue of 3D Printing Report. It will explore challenges related to AM materials and the research that will tackle these issues in the next five years.