The method with sensing of MIG welding pool surface is studied in this paper.The distributing of arc action
spectrum, pool reflecting action spectrum and pool radiating action spectrum are analyzed. The radiation is weaker at
interzone 500-700nm. So, the structured light source is confirmed to semiconductor laser at wavelength 650nm. Narrow
band filter and neutral density filter are mounted on CCD, they are good for restrained the influence of arc. The pool
width is studied on small current by experimented, deforming and distributing of structured light are confirmed. The
form and sort of splash are studied, the method of reducing and protecting splash are also studied. Welding current is
selected properly to restrained splash. Incident angle of structured light is 30 degree. The MIG pool image is captured by
CCD. Deformed structured light fringes are reflected the information of the concave or convex of the pool.
An active vision sensing system which established by low power laser and common CCD is used to shoot GTAW
welding pool images. Based on choose the appropriate LASER and filters, projected angle of laser and shoot angle of
CCD, we avoid the disturbance of arc effectively and obtain clear images of the welding pool. The shape parameters of
welding pool can obtain by demarcated and calculated. And then a three-dimentional numerical model of GTAW welding
pool is established based on the theories of fluid dynamics and heat transfer. It considered the convection heat transfer of
liquid metal and heat conduction of solid metal. And FLUENT software is used for simulate the GTAW welding pool.
Extract the weld pool shape parameters and done comparative study with the vision detection of pool. This will be
beneficial to avoid repeat experiments and improve work efficiency.