Real-Time Weld Inspection Tool (RTWIT) to Enhance NAVSEA Shipyard Logistics Operations

NAVSEA steelworkers and artisans weld parts to sustain naval operations underway and in shore-based maintenance depots. However, labor shortages and manual processes reduce the accuracy and speed of maintenance activities. As of 2024, 21.4% of welding professionals in shipbuilding are 55 and older, and over 159,000 are approaching retirement. The military industry is behind on ship production and repair, and the government's clean energy efforts, infrastructure projects, and semiconductor foundries also require welders. Currently, the arc welding methods appropriate for thick metal sections is a highly manual and error prone process, requiring at least five years of practice to master. These challenges cause maintenance and repair bottlenecks and reduce the time it takes to return assets to the fleet. To address this challenge, aRoboticsCompany proposes the Real-Time Weld Inspection Tool. RTWIT is a portable, augmented reality (AR), hood-mounted spectroscopic weld inspection system. It detects weld defects by quantifying luminosity of wavelengths in the arc emission spectra that the human eye cannot differentiate. RTWIT identifies and allows for reactive repair of weld defects on NAVSEA components undergoing maintenance. RTWIT utilizes an ultraviolet (UV)-Vis spectrometer and AR display to notify welders of the location and nature of weld defects. RTWIT enables on-the-line inspection during the welding processes by detecting weld defects as they are formed within the workable molten pool of metal under the arc. RTWIT’s spectrometer quantifies emission intensity by wavelength over time, with a maximum spectral range of 300 to 1100 nm, minimum resolution of 0.8nm, and frequency bandwidth of >1MHz (temporal resolution of <1µs between luminosity measurements). This allows RTWIT to pick out anomalous emissions in wavelengths that are known to represent hydrogen inclusion, gas contamination, and porosity in the weld. RTWIT also detects and characterizes short-lived anomalies in arc brightness that indicate poor torch-holding, tip standoff distance, slag inclusion, undercut, or lack of weld fusion to base metals. RTWIT uses non-contact spectrometry to analyze light from welding arcs, sensitive to spectral variations from high-temperature sources. Accuracy relies on atomic physics; elements in excited states emit photons at discrete wavelengths unique to their energy levels, mostly invariant to temperature and electrical environments. This enables detection of surface contaminants like sodium and potassium salts, hydrogen from moisture or oil, and copper residue along the weld line. RTWIT performs real-time analysis to distinguish false positives, as genuine weld defects create distinct clustering patterns due to long-lived sources like poor technique or voltage sag. Arc spectroscopy effectively detects defects in various materials, including carbon steel, stainless steel, and aluminum, across different welding methods such as TIG and MIG.