Good Weld

Bad Weld Impact's ARCAgent uses Weld Signature Analysis techniques for realtime analysis and detection of weld process problems.

U.S. Mfg. Corp., Warren, Mich., extrudes axle tubes with precise but variable wall-thickness using its patented process. It then welds a flange and two brackets to each tube in a 3-stage process involving an automated two-torch, lathe-welding setup for the flange and two dual-robot cells for each bracket. The company's arcwelding processes, including GMAW, pulsed metal core, flux core, depend on customer requirements. Needing to ensure weld quality, the company instituted a continuous improvement program, regular destructive testing, preventative maintenance, and a real-time arc-weld-monitoring system from Impact Engineering Inc., Jackson, Mich.

This system comprises Impact's ARCAgent 2000 weldmonitoring units, ARClient software, and ARCharter database. With the system, U.S. Mfg. now detects and then eliminates welding problems such as false arc starts, incorrect weld duration in the weld sequence, and premature part end. It then uses the collected data to define the projects and goals of the company's continuous improvement program.

Each welding torch features arc-weld-monitoring sensors that measure current, voltage, wire-feed speed, and gas flow. This data is sent to the monitoring units, which then exchange information with the cells' programmablelogic circuits or robot controllers about which part to produce, when parts are clamped-in and finished, and what weld faults occurred. This information is relayed to a PC running ARClient software for collection and display. From the PC, the information goes to a plant server hosting the ARCharter welding information database. The server lets engineers chart and visualize welding information from any of the plant's cells and computers in real-time or view and control from any networked computer.

U.S. Mfg. says the system has reduced downtime and time used to diagnose problems. Because engineers and technicians can readily access weld records, they eliminate or quickly test for and identify potential problems.

For example, recently the weld monitoring system identified a wire-feed-speed problem with some newly purchased torches. The feeders operated at the correct speed but with too much internal physical resistance, causing erratic wire slippage in the guide rollers. The welds were visually consistent, but lacked correct root penetration. With the monitoring system, the company identified the problem as a misplacement of an internal crimping.

Also, the company says the systems also lets it identify liner wear early-on. As liners wear and cause wire-feed problems, hard-to-identify undercuts in welds occur. The system identifies this erratic wirefeed speed and the need for preventative maintenance.

Ready access to the weld record also lets personnel optimize and select stable process operating points, increasing cells' operational and stability and reducing scrap rates.

Impact Engineering Inc.
Warren, Mich.
impacteng.com