3D metal printing monitored without using sensors
In spite of its explosive market growth, 3D metal printing is challenged by the thermal stress resulting from the high printing temperatures and the layer-by-layer nature of the printing. The stress commonly results in warpage and inadequate bonding between the layers. Therefore, real- time monitoring of the printing is greatly needed to provide better control and a record of the printing. Cameras commonly used for the monitoring is inadequate for looking at the interface between the layers. A new invention by Professor Deborah D.L. Chung of the Department of Mechanical and Aerospace Engineering, University at Buffalo, The State University of New York, is about to transform the monitoring technology. This invention unprecedentedly provides monitoring without using any sensor, as the printed layers sense themselves. The self- monitoring is enabled by the measurement of the capacitance of the metal printed object as the printing proceeds. The measurement of the capacitance of a metal is unprecedented in the world of science, due to the electrical conductivity of a metal. For the self-monitoring, there is no need to modify the printed layers. The advantages of self-monitoring compared to the use of sensors are low cost, high durability and installation simplicity. A patent is pending and the technology is available for licensing. The work is described in a paper just published in Sensors and Actuators A. The paper is co-authored by Sanjaya Somaratna, an undergraduate student.
Chung is the foremost scientist in the world in the field of structural self-monitoring, having worked in this field for about 25 years, with smart concrete being her most well-known prior invention. She received her B.S. and M.S. degrees from Caltech in 1973, being one of the four first woman graduates of Caltech. She received her Ph.D. degree in Materials Science from MIT in 1977.