Real-Time Optical Defect Detection, Identification and Correction Technology

Intellisense Systems, Inc. proposes to develop a new Real-Time Optical Defect Detection, Identification and Correction (ODIN) technology for wire-feed additive manufacturing (AM) based on a multi-sensor approach combined with a defect-correction algorithm. The ODIN system will enhance NASArsquo;s current AM capability for space applications and structure reliability monitoring. The ODIN system consists of two underlying technological modules: (1) the sensor module, which combines optical high-resolution spatial mapping, an IR camera for thermal mapping, and a wire-feed speed monitor for nozzle clogging detection; and (2) the defect detection, identification and correction software module, which creates a surface from the point cloud of each printed layer, compares it to the CAD model of the part, determines location, volume and type of defect and creates new printing instructions to correct detected printing defects. The innovations of ODIN include the use of a structured light COTS 3D scanner for detection of spatial defects, a miniature IR camera to monitor part temperature, and an optical encoder of wire-feed speed to detect nozzle clogging to cover virtually all causes for printing defects and correct them in real time. To identify and correct spatial defects, the surface point cloud of the printed part is compared to the corresponding sections of the partrsquo;s CAD model in real time for feedback control. These monitoring methods target a broad range of defect types that can be captured immediately. In addition, when a discrepancy above the user-specified threshold level is detected at a certain location, ODIN computes additional 3D printing steps necessary to correct the defect. Material testing will be performed to estimate the impact of real-time print correction on the partsrsquo; mechanical properties. This novel development will significantly reduce the need for post-build full part inspection and re-printing in case of inferior part quality.