Machine Vision Systems & Software Case Studies

Using Machine Vision Technology to Improve Weld Quality

By Bob Rongo, Decision Technology, LLC

A basic fact in the world of welding: poor weld quality will result if the weld process is started with the weld wire out of position. As a machine vision integrator, Decision Technology, LLC has developed a cost-effective machine vision system that checks wire position (setup) prior to the start of a weld. This system, retrofitted on fixed spindle welders, inspects the weld wire setup position and reports necessary adjustments to the wire position prior to the start of a weld cycle. The system uses a single camera per torch, (a pair of cameras per double ended spindle welder) in conjunction with a back-lighting scheme. At the start of a weld cycle an image is captured and processed to determine the projected trajectory of the wire into the root of the weld grove. The trajectory point is then compared to a specified bias and set of acceptable boundary conditions. A user configuration table, specific to the weld, contains process parameters such as: bias distance and acceptable boundary limits with respect to the root.

Should an unacceptable offset be measured, the vision system can report offset in one of two ways. One, the correction (how much to move the torch) can be reported on an operator screen for manual adjustment of the torch. Two, the processor can directly report the offset to a motion system that controls torch position. Additionally the system can measure the torch stand off distance with respect to the work-piece. A failed standoff distance can be due to wrong setup or excess slag buildup on the nozzle. Using a machine vision system to measure and maintain these key parameters has been proven to improve weld quality. The system can easily interface to any PLC type controller.

For more information about how Decision Technology LLC can improve your manufacturing efficiency  or quality control by developing custom machine vision software, email Bob Rongo, call our Indianapolis, Indiana headquarters at 317-272-2577, or fill out the form below: