In situ Additive Manufacturing (AM) Monitoring Using Complementary Metal Oxide Semiconductor (CMOS) Technology
Research into vision and image sensing techniques has resulted in innovative in situ monitoring techniques such as imaging using thermal cameras and pyrometry. However, these techniques are not currently being used to detect defects or monitor processes in commercial desktop-type FDM printers as they are considered too expensive for these printers. Affordable, innovative, and reliable in situ monitoring processes must be developed to improve the build quality in Additive Manufacturing. This project utilized Complementary Metal Oxide Semiconductor (CMOS) sensors and integrated computing, incorporated into a desktop-type FDM AM printer. The methodology involved creating a closed control loop around an FDM printer with a programmable Integrated Circuit (IC) as the controller and a CMOS sensor as the sensing input device. The CMOS sensor (camera) was used to capture an image of the build platform with the printed part after specific layers, and the image is sent to the microcontroller. The controller processes this image as well as the image from the printer’s input file and converts both images to histograms. The conversion to histograms occurs by creating bins on the horizontal axis of a graph to represent different image pixel intensities. Histograms are compared and assigned a correlation factor. If this assigned correlation factor falls within the user’s pre-defined threshold, the printer is instructed to build the next layer, otherwise, the printer is instructed to pause or stop printing.
"In situ Additive Manufacturing (AM) Monitoring Using Complementary Metal Oxide Semiconductor (CMOS) Technology"
ETD Collection for Tennessee State University.