Page 27 - 3D Metal Printing Fall 2018

CT Scanning
for AM Inspection
FEATURE 3D
This nondestructive-testing method is ideal for inspecting complex parts and internal lattice structures.
BY JEFF URBANSKI
As additive manufacturing (AM) moves quickly from rapid proto- typing to a valid process for reliable low-volume production parts, computed- tomography (CT) scanning technology becomes increasingly important as an inspection and nondestructive-testing platform. However, many AM providers remain unfamiliar with how CT can help improve and monitor production quality, or they have misconceptions regarding CT capabilities and the cost of incorpo- rating it into their processes.
Let’s address those misconceptions and clarify how recent advances in CT-scanner design and technology provide the speed and price-performance ratios that make it an indispensable choice for inspecting the complex parts and internal lattice structures of AM parts.
See More So You Can Do More
AM provides designers with freedom to create anything that they can imagine. However, that freedom comes with a com-
Jeff Urbanski is key account manager for Yxlon, Hudson, OH; 234/284-7849, yxlon@yxlon.com, www.yxlon.com.
promise, as the more intricate and com- plex the structure, the more difficult it becomes to inspect. This creates quite a challenge for busy manufacturing plants, but is where the power of CT scanning reveals itself.
CT is the latest, and perhaps the most powerful, development in the modern era of nondestructive testing—quite a boast, but let’s see why.
A CT scan produces a 2D density map of a cross-sectional slice of an object’s interior. A 3D volumetric model can be produced from many of these views taken at different viewing angles and then recon- structed using a computer. Many 2D slices can be combined by powerful software to produce a 3D image of practically any part, object or product. This is critical for any application where a manufacturer
wishes to see inside of an object without destroying it.
Today’s industry CT scanners offer advanced functional capabilities that pro- vide extremely valuable data for initial prototyping and for optimizing produc- tion processes. They can detect potential part failures, even on larger parts. This had never before been possible, but is now because CT-scanning techniques produce crystal-clear images that are superior to other modality choices. These images can assist manufacturers in a comprehensive fatigue analysis of parts and enable them to identify finite cracks and inconsistencies from part to part. Substrate bonding issues, uneven mate- rial flow, and density and porosity prob- lems also can be detected through the accuracy of CT images. CT screening
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