Standards Spur 3D Printing

Jack Maxwell

ASTM is spearheading an effort that will standardize requirements for the reliability and interoperability of additive manufacturing technologies.

At one time the manufacturing landscape was dominated by huge factories filled with massive machine tools and loud, hectic production lines. Think of the steel mills of Pittsburgh and Germany's Ruhr Valley, or the sprawling auto-making complexes of Detroit and Toyota City. Still in existence, of course, they represent the apotheosis of the Industrial Revolution, and generally rely on the physical labor of an army of men and women - mechanical engineers and production assemblers, pipefitters and millwrights.

But these enterprises are not the only game in town. At the intersection of traditional and digital manufacturing lies smart manufacturing. Combining the precision data-gathering and control capabilities of powerful computer systems with sophisticated equipment like robots, automated machines and lasers, smart manufacturing improves the quality and accuracy of finished products while reducing the physical burden on workers.

Smart manufacturing is evolving on many fronts. A particularly promising technology is known as additive manufacturing, or AM, and it's the focus of ASTM Committee F42 on Additive Manufacturing Technologies. This group is a key player in ongoing efforts to establish standards for this rapidly evolving industry.

Building Parts, Layer by Layer

Many component parts of modern machines and devices are produced by subtractive manufacturing, which starts with a solid piece of material, frequently metal, and carves away at it to arrive at the final desired shape. Material is removed - or subtracted - via cutting, grinding, drilling or other mechanical operations.

Additive manufacturing, however, builds three-dimensional objects by adding successive layers of material, one atop another, as directed by a CAD (computer-aided design) file that contains all the necessary parameters: thickness, shape, contours, etc.

Since the early days of 3D printing in the 1980s, a number of new AM technologies have evolved: material extrusion, directed energy deposition and powder bed fusion. Each process is distinguished by the material used and how layers are deposited.

What all these AM technologies have in common, however, is the need for a robust international consensus on standards. In the words of John Slotwinski, Ph.D., an additive manufacturing development engineer at the Johns Hopkins University Applied Physics Laboratory, "Standards will allow everyone to do things consistently and correctly, and to have the confidence that others who are using the same standards are also doing things correctly. This kind of uniformity will help propagate the technology, in part because the consistency will allow us to definitively compare things properly."

The Promise and the Challenge

Aerospace and military applications are among the most promising markets for additive manufacturing. Mary Kinsella, in her role as senior manufacturing research engineer and leader of the Additive Manufacturing Integrated Product Team at the U.S. Air Force Research Laboratory, has seen the potential of AM. She also knows what's needed for the technology to fully realize that potential.

"Presently, for the aerospace sector, the key applications for structural AM are tooling, fixtures, form-fit models and design iteration," Kinsella says. "AM is beginning to make an impact by reducing lead times for all these applications. Some noncritical, nonstructural part applications, such as polymer environmental ducting, are already flying."

Producing prototype parts quickly via AM, as opposed to waiting for a mold or die to be produced and shipped before part production can even begin, is a critical benefit, Kinsella notes. AM also allows for faster and less expensive design changes, and in her view, could eventually be used both to replace parts for which tooling is no longer available and to build parts "on demand" in lieu of maintaining extensive spare part inventories.

Kinsella points out that "many of the AM standards that are used today for military systems are proprietary. [Also,] individual companies have developed their own internal capabilities, which remain their intellectual property. [But,] as AM technology and understanding mature, public standards are needed to provide a common language and to guide those entities that do not have the resources to develop their own standards."

An International Effort

Carl Dekker is on the other side of the supplier–customer dynamic from Kinsella, but he sees the same issue with "silos" - that is, people in the AM industry working independently on their own specialties without the common reference point of industry-wide standards.

Dekker is the president of Met-L-Flo, a leading firm in the additive manufacturing industry; he is also the chairman of ASTM Committee F42. "The current industry maturation level is very low," he says. "Everyone has had to learn their own way through it, with no trail to follow."

To blaze that trail, Committee F42 is partnering with other international organizations, including the International Organization for Standardization (ISO) and America Makes, the National Additive Manufacturing Innovation Institute.

In 2011, ASTM and ISO established a formal agreement for joint development of AM standards by ASTM F42 and ISO Technical Committee 261 on Additive Manufacturing. This agreement represents a key milestone in collaboration between the two organizations that will result in co-branded ASTM and ISO standards. Later that same year, ASTM signed a memorandum of understanding for the development of AM standards with the National Center for Defense Manufacturing and Machining, which manages America Makes.

Eleven ASTM standards have already been developed and approved in the nearly six years that Committee F42 has been active, including three jointly issued with ISO. These include a specification for AM file formatting, a practice for reporting data for test specimens made by AM and a guide for characterizing the properties of metal powders used in AM. All of these standards give manufacturers and users of AM equipment a common language when designing parts and using or testing AM materials, software and hardware.

More than 10 work items are under development, which include guides and test methods that will improve design, materials and processes.

A New Era in Manufacturing

Potential applications for additive manufacturing are diverse and complex. Imagine being able to craft custom implants that help mend shattered skulls and replacement joints personalized to fit each patient. Picture astronauts circling high above the earth in the International Space Station, able to produce parts needed for repairs on the spot. Consider the implications of being able to create new designs that are difficult, or perhaps even impossible, to make using traditional methods.

As standards and system advances address issues of repeatability, performance and scale, additive manufacturing will become an ever-more valuable technology for a fast-changing world. As Kevin Jurrens, deputy chief of the Intelligent Systems Division of the National Institute of Standards and Technology and a member of Committee F42 puts it, "Additive manufacturing systems are already providing an economic boost for manufacturers by shortening their product development cycle, increasing the quality and functionality of manufactured parts, and allowing rapid changes to the complex tooling used to create new products. The impact of additive manufacturing will continue to grow as system capabilities and manufactured parts continue to improve to meet the demands of manufacturers and their customers."

ASTM Executive Vice President Speaks at AM Events

On Oct. 7, Katharine Morgan, ASTM's executive vice president, gave opening remarks at a two-day technical exchange organized by Penn State's Center for Innovative Materials Processing through Direct Digital Deposition, or CIMP-3D. The event was co-sponsored by ASTM and other organizations such as America Makes, an innovation institute with whom ASTM has a memorandum of understanding.

Before the event, Morgan toured CIMP-3D with its director, Richard Martukanitz, Ph.D. They viewed 3D printers and 3D-printed parts on display, discussing how this technology has the potential to enhance design, drive innovation, lower costs, reduce waste and provide other societal benefits. In particular, they discussed the growing interest in using metals to create an array of products ranging from airplane parts to medical devices. Morgan also met with Neal Orringer, vice president for alliances and partnerships at 3D Systems, which had just announced a partnership with CIMP-3D.

In her remarks to kick off the technical exchange, attended by about 200 leaders in the field, Morgan said that 3D printing has the potential to transform industries like transportation, medical care and other fields, ultimately "helping our world work better." She said, "I believe that standards play a crucial role in innovation. They are the bridge between research and the marketplace. The potential for 3D printing to improve society is absolutely compelling."

ASTM staff also spoke about additive manufacturing at two other recent events:

Pat Picariello, an ASTM director, stressed how standards can promote knowledge, stimulate research and drive technology at the Additive Manufacturing European Conference in Brussels, Belgium, in June.

Sara Gobbi, ASTM Brussels representative, spoke to companies, industry organizations and others at the International Conference on Additive Manufacturing in Milan, Italy, in October.

Jack Maxwell is a freelance writer from Westmont, New Jersey.

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