Recent discourse surrounding the future of advanced manufacturing has been dominated by two methodologies. Computer numerical controlled (or CNC) machining remains the most widely used method of industrial production today. Additive manufacturing (AM), though pioneered in the 1980s, has only lately advanced far enough as a technology to figure significantly in the production processes of manufacturers. While both CNC machining and AM have distinct advantages that make them indispensable to modern manufacturers, neither is without drawbacks.
In the interest of spreading awareness of metamorphic manufacturing, or robotic blacksmithing, many of the leading minds in the space recently came together to publish Metamorphic Manufacturing: Shaping the Future of On-Demand Components. The Minerals, Metals, and Materials Society (TMS) sponsored the technical paper, which was initially released at the end of 2019. The piece is the most comprehensive work to date on this new manufacturing technique, and as such has garnered widespread attention from academia and industry alike.
What is Metamorphic Manufacturing?
This budding ideal of robotic blacksmithing does not represent something wholly new, but rather a fusion of established manufacturing concepts into a process more potent than any existing method. It borrows from not only CNC machining and AM, but also from more traditional methods of metalworking and well-understood metallurgical properties. The authors note that these technologies have yet to be combined into anything resembling an organized system—and therein lies the opportunity.
Summarized as briefly as possible, metamorphic manufacturing uses numerically controlled processes (including thermal manipulation) to incrementally form materials into components with specific geometric and engineering properties. It uses a system comprised of sensors, thermal control, actuators and forming tools, robotic manipulation systems, and computation to mimic the processes of a human blacksmith with a much greater degree of precision and speed.
Notably, once fully developed, metamorphic manufacturing’s adherents envision a process that is neither additive nor subtractive in nature. A metamorphic manufacturing system, therefore, could theoretically take an exactly measured piece of raw material and form it into a complex component at near zero waste. The limits on part complexity and engineering/structural properties would also be extended beyond what is achievable with the manufacturing methods of today.
A Clear Value-Add Across Sectors
The stated goal of the paper was to “jumpstart” the conversation around this new ideal, and hopefully spur investment from both the public and private sectors in further research and development. The study articulates very clearly why such investment might be justified.
First, there’s the relative absence of waste to consider. Because metamorphic manufacturing manipulates the raw material in multiple different ways to arrive at a final part, it’s more material-efficient than other methods. Considering the imperfections associated with AM (adding/layering) and CNC machining (subtracting/cutting), this might constitute a real improvement for manufacturing. In the metamorphic process, once the correct volume of material is determined, there is virtually no change in that volume when the manufacturing process occurs. That can lead to a major drop in material and energy usage, savings which might flow directly to the bottom line of a manufacturer.
The technology (once further developed) could also allow for much more design freedom and control than what’s achievable today. While the second wave of digital manufacturing (AM) marked a large improvement over the first (CNC machining) in this regard, metamorphic manufacturing could take it a step further. Rather than layering material on top of itself to achieve complex part geometries as in AM, this method would use a single piece of material. Further, the use of complex sensors and thermal manipulations broadens what might be possible in terms of part quality. Given the virtually limitless flexibility in terms of heating and mechanical manipulation available to traditional, human metalworkers, what might robotic processes be able to achieve?
Lastly, it’s worth noting the business opportunities that metamorphic manufacturing might unlock for businesses of all sizes due to its versatility. The method is inherently scalable—the tooling, sensors, and robotics involved can be as small or large as desired. This eliminates the need for space to house a massive suite of equipment for businesses without suitably massive resources. The other big advantage in terms of speed and cost is the substitution of dynamic tooling for expensive, part-specific dies. Cutting out the need to maintain a full set of dies for every unique component could unlock major time and cost savings for small players. This concept is an extension of the advantages presented by AM for fast, inexpensive prototyping and small batch production of complex components. The high-leverage capital investment associated with producing a few specialized pieces becomes even less intimidating with “robotic blacksmithing.”
Obstacles to Development
While the case for further research and development may be clear, the difficulties associated with arriving at a fully formed metamorphic solution should not be discounted. When asked to identify the biggest obstacles to widespread adoption of the method, the research team assigned to the study noted several key problems. Some are technical while other issues are more qualitative, but all represent bridges that will need to be crossed before metamorphic manufacturing can find a spot on the shop floor.
On the technical side, the integration of sensors sophisticated enough to control and inform the incremental deformation process is perhaps the greatest roadblock. Most importantly, engineers have to identify the relevant data to collect about a given material in order to install the right sensors. While this may sound straightforward, the paper notes that the chosen sensors need to not just accurately gather the right information, but also do so in a fast-paced, dynamic manufacturing environment. Once the selection process is taken care of, integrating the sensors with the robotic systems that actually form the material is no easy task. The authors note that neither the hardware nor the software aspects of such an implementation would be straightforward and will require some pioneering work.
A related challenge is the lack of a truly comprehensive understanding of many classes of materials that might be used in metamorphic manufacturing. Materials science simply isn’t developed enough as a discipline for there to be a full, “predictive understanding of the processing-structure-property-performance relationships for all possible MM materials.” Though this initially appears a high bar to clear, a thorough knowledge of all material properties will be necessary for consistent production. Because the nature of metamorphic manufacturing is constant change and deformation, much more reliance will be placed on in situ characterization methods. The microstructural changes undergone by stock material in this process will necessitate a much deeper knowledge of path-dependent behavioral material properties.
Long-Term Possibilities
Metamorphic Manufacturing: Shaping the Future of On-Demand Components came together as a project with the goal of accelerating the timeline on which these challenges might be tackled by the manufacturing community. The authors presented a number of “action plans” for advancing the discipline, but they also concluded the paper by dangling the proverbial carrot. The third wave of digital manufacturing, claims the paper, is a culmination of the promise of its technological constituents. The foundational processes are all nearing maturity, but there is tremendous opportunity in their yet-to-be-realized union into a practical system.
The specifics of that opportunity, however intriguing, remain poorly understood. The value proposition for metamorphic manufacturing is vague: more design freedom, higher part quality, less waste, lower barriers to entry, better production times. The theoretical limits of the technology are not at all defined. There remains a dearth of quantitative research on material-specific, unique metamorphic processes that are clear improvements on existing methods.
The reality of a fully formed suite of manufacturing technology working in concert as a true “robotic blacksmith” remains distant, but the possibilities are tantalizing.