Some metal additive manufacturing processes can produce parts with internal porosity, either intentionally (with careful selection of the process parameters) or unintentionally (if the process is not well understood.) Material porosity is undesirable for aerospace parts - since porosity could lead to premature failure - and desirable for some biomedical implants, since surface-breaking pores allow for better integration with biological tissue. Changes in a part's porosity during an additive manufacturing build may also be an indication of an undesired change in the process. We are developing an ultrasonic sensor for monitoring changes in porosity in metal parts during fabrication on a metal powder bed fusion system, for use as a process monitor. This paper will describe our work to develop an ultrasonic-based sensor for monitoring of part porosity during an additive build, including background theory, the development and detailed characterization of reference additive porosity samples, and a potential design for in-situ implementation.
Proceedings Title: 40th Review of Progress in Quantitative Non-Destructive Evaluation
Conference Dates: July 22-26, 2013
Conference Location: Baltimore, MD
Pub Type: Conferences
Additive manufacturing, porosity, Archimedes, X-Ray Computed Tomography, ultrasonics, non-destructive evaluation