Pohlman, Nicholas A.
M.S. (Master of Science)
Department of Mechanical Engineering
Directed energy deposition (DED) is a metal additive manufacturing method of creating parts by using a high-power laser to fuse powdered metals into fully dense three-dimensional structures. To ensure the geometric and mechanical integrity of the completed part, the powder flow rate of the DED system must be accurate and repeatable for manufacturability. Due to its opacity and reflectivity, one method of measuring powder flow is by utilizing an optoelectronic sensor. The sensor consists of a diode laser with a line generator that emits a thin defocused light sheet, a photodiode, and a set of lenses. The corresponding lens collimates the laser beam before passing through a transparent chamber where powdered metal is carried by argon gas flow. Due to diffusion, absorption, and reflection of the powder stream passing through the glass chamber, the amount of light detected by the receiving photodiode would change as the density of the powder changes.
Research carried out in the Advanced Research of Manufacturing and Materials lab is in the process of developing a standard for the use of an optoelectronic sensor for measuring powder flow in DED applications. In-situ experiments used with an OPTOMEC 850M LENS powder feeder measure the mass flow rate of 316L stainless steel powder. The consistency of mass flow rates will be monitored in order to develop a standard for the use of this sensor.
Sliwka, Mark, "In-Situ Optoelectronic Powder Flow Measurement Analysis For Directed Energy Deposition Applications" (2020). Graduate Research Theses & Dissertations. 7677.
Northern Illinois University
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