Tips

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I'm going to talk about the characterization of the surface roughness of additively manufactured (AM) metal parts this month. This is a relatively new challenge, and organizations like ASTM are developing standards and recommended good practices. (ASTM 2020, ASTM 2023)

Characterizing the surface roughness of metal AM parts presents unique challenges due to their complex geometries and internal surfaces that are inaccessible by traditional methods, such as contact and optical measurement methods often fall short.

Characterizing the surface roughness of AM parts is crucial to compare their characteristics to the parts made by traditional techniques. Roughness is also closely related to the parts' performance. It can cause corrosion or create crack initiation sites. (Mirabal et al., Additive Manufacturing 2023, The Importance of Surface Finish in Additive Manufacturing, Enginering.com)

Here is why I'm talking about this: I believe X-ray CT can offer a lot of help in resolving these unique challenges. It can generate 3D surface models of AM parts, however complex the texture is. The surface even doesn't need to be flat or exposed. Here are a couple of published studies on this topic.

• X-ray CT and image analysis methodology for local roughness characterization in cooling channels made by metal additive manufacturing (Klingaa et al., Additive Manufacturing 2020)
• Internal Surface Roughness Measurement of Metal AM Channels via X-ray Computed Tomography: A Case Study (Lifton et al., e-Journal of Nondestructive Testing 2022)