Additive Manufacturing

JUL 2018

ADDITIVE MANUFACTURING is the magazine devoted to industrial applications of 3D printing and digital layering technology. We cover the promise and the challenges of this technology for making functional tooling and end-use production parts.

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JULY 2018 Additive Manufacturing 14 TAKING SHAPE Indeed, the opportunity today falls into three categories, says Cox—"three buckets," he says—and the most important one is the bucket most affected by the capabilities of today's machines. Those buckets are: • Drop-in material replacements. In this area of materials development, the suppli- er can develop its own, more competitive version of some existing material—say, its own version of a polycarbonate filament for FFF similar to an existing version. • New materials for standard print profiles. Within the sets of printer parameters used for established materials, the materials company might be able to engineer new materials with special properties. A new SABIC filament delivering high toughness for consumer electronics and automotive applications is an example. • New materials leveraging nonstandard print profiles. This third category is the most exciting area of material development. The most promising new material options tend to push 3D printers by requiring operational parameters differ- ent from the parameter sets locked into established machines—machines that might have been invented with prototyping rather than production in mind. For example, polymers engineered to withstand high-temperature applications need printers not only able to achieve the required high extrusion temperature, but also able to give the operator the capacity to employ that temperature. Another mate- rial might require a distinct and specific print speed or layering height. Machines offering an "open format"—that is, user ability to adjust machine settings govern- ing the build—are becoming more valuable as materials advance, Cox says. "Our goal is to develop unique materials targeted to end-use applications," he says. Because, really, that has always been the goal. As 3D printing takes its place as a conversion process for production, it will increasingly find its opportunities the way other processes do. That is, the end user of the part will seek a material based on the properties that part requires. Then, material engineering combined with the capabilities of the printer will determine whether 3D printing is indeed a viable option for making that part. The same device that is used to inspect the metal powder prior to an AM build might also be used to validate the parts resulting from that same build. At the most recent Rapid + TCT, Thermo Fisher Scientific demonstrated how its new compact scanning electron microscopy (SEM) unit, Explorer 4 Additive, can do both jobs. Key to this multitasking is the fact that the voids and inclusions that might invalidate an AM build are just as identifiable to SEM as grains of powder, and even have roughly the same morphology. "Basically, we are looking for either light shapes or dark shapes, and we derive meaningful data from both," says Kristin Mulherin, company senior business development manager. Scanning a sample batch of powder is the "light shapes" exercise. While energy-dispersive X-ray spectroscopy is applied to validate the chemical composition of each grain to confirm there is no contami- nating material in the mix, optical detection of each grain (the light shapes against a dark background) maps and measures grain forms to record the dimensions of perhaps 1,000 grains of powder in an inspection cycle taking 15 minutes. The consistency or extent of variation in the size and sphericity of powder can then be used to In Metal AM, One Device Inspects Both Parts and Powder By Peter Zelinski

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