We continue a conversation with Dr. Michael Grieves, Chief Scientist for Advanced Manufacturing at Florida Institute of Technology and the person who coined the term Digital Twin. For the first part, visit https://blogs–3ds–com.apsulis.fr/northamerica/dr-michael-grieves-additive-manufacturings-mythbuster/.
When Chuck Hull invented the first 3D printing technology in 1983 (stereolithography) it started with an ah-ha moment. He imagined UV-curable resin as layers of plastic instead of being used like varnish. After the initial epiphany, inventing the first 3D printing method was just a matter of working out how to automate the process.
Hull had an initial idea about materials, but it was useless until he invented the printing process. This is just one more example of what advanced manufacturing researcher Dr. Michael Grieves notes as a quasi-law of manufacturing technology: “Process always precedes content.”
Henry Ford is the quintessential example, Grieves explains. Ford had access to content: the internal combustion engine and sheet metal were already invented. Ford’s breakthrough was to create an assembly line using standardized, interchangeable parts.
Today the challenges in additive manufacturing — what we now call 3D printing for industrial purposes 
— still remains a matter of process before content. “Ford had to get the assembly line running. We have to establish the processes of how to interact with various materials,” Grieves observes. Materials scientists are hard at work creating new materials, but the processes of how they become parts or products must come first. “What is the laser wavelength? What is the build size? We need this before we can tinker with custom materials.”
To help sort out the thinking processes required to take us to the next generation of additive manufacturing, Grieves relies on the methodology known as SAM/CT: Size, Accuracy, Materials / Cost, Throughput. First described by Dr. Susan Smyth, Chief Scientist for Global Manufacturing at General Motors, Grieves explains that SAM-CT is a great way to frame the right questions to get the right answers.
“There are two questions to ask,” notes Grieves. “The first is, ‘Can I do it?’ The second is, ‘Should I do it?’ Too often people answer the first question but ignore the second one.”
The category of software tools known collectively as Design for Additive Manufacturing (DfAM) is a good example. “We need design tools that can incorporate multiple parts, for example,” says Grieves. The processes have to be modeled as well as the design. “There is functionality you can’t get except by using additive manufacturing, like cooling tubes inside solid metal.” The software needs to be capable of what Grieves calls “higher-level goal seeking” to allow such AM-specific designs to be created. “The question needs to be ‘what is the function we are seeking?’ as opposed to ‘how do I cobble together parts to get that function?’”
Process comes first, but Grieves is not caught in some chicken-or-egg origins loop regarding the future of additive manufacturing. Materials will be “a big part of this,” he says. Today engineers look to see what materials are available, and take it into the design process. “In the future custom materials will be selected for the job,” Grieves says. An engineer will specify special capabilities, temperature range, flexibility, and other specifications, and the materials manufacturers “will custom make it. We won’t have to pour it into a big vat like an old factory. [Materials makers] will tailor the material to the idea.”
In this scenario, Grieves says the DfAM software becomes even more important. “Now I worry about geometry, but I should worry about the design for this material on this machine.”
To advance the evaluation of additive manufacturing, Grieves and Smyth teamed up with SME and General Motors in 2017 to launch an initiative called iTEAM, for Independent Technical Evaluation of Additive Manufacturing. The partnership’s goal is to provide manufactures with an expert system to compare and calculate the right AM machine, material, and process for any specific job, and to build a community that shares experiences and feedback.
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To learn more about the Future of Additive Manufacturing, check out 3DEXPERIENCE: A Virtual Journey, Dassault Systèmes on-line, on-demand event series. Episode 3 with a focus on Additive Manufacturing goes live on September 23.
