Sigma Labs Inc (SASI)

[VisionaryInc]

Search citation 22, sigma labs and Honeywell.

Non-Destructive Techniques and
Technologies for Qualification of Additive
Manufactured Parts and Processes:


7.3 Internal Defects
Porosity is, by far, the most investigated and documented defect in the additive manufacturing literature. A scholar.google.com search for "additive manufacturing" and porosity returns 3,760 results; contrast this with the 1,020 returned for metal precipitate, 208 for microcrack, or even the 170 returned for NDE or NDT and "additive manufacturing". This is, perhaps, because porosity is relatively easy to measure, or at the least approximate, and has historically been one of the major hurdles in additive manufactured metal parts. Perhaps the simplest method of approximating the porosity of a part is to divide its measured mass by the part volume as computed from the input CAD, a 3D scan of the built part, or from images collected during the
build phase post-processed to calculate the final part shape 22. Provided that the fully-dense density is known, a simple comparison of the measured and theoretical densities produces the
porosity [297]. Other NDE methods for measuring/visualizing porosity include: Archimedes' principle, computed tomography, ultrasonic NDT, radiography and thermography.

22 Commercial implementation of such a technology, applicable to SLM, is being developed as a collaboration between Sigma Labs' B6 Sigma and Honeywell Aerospace [296].


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