WeldSaver protects automated welding systems when weld tips are lost

Citation

(1998), "WeldSaver protects automated welding systems when weld tips are lost", Industrial Robot, Vol. 25 No. 3. https://doi.org/10.1108/ir.1998.04925caf.005

WeldSaver protects automated welding systems when weld tips are lost

WeldSaver protects automated welding systems when weld tips are lost

Keywords Automation, Protection, Proteus, Welding

(Water shut off in < 1.0 second Low flow alarm signalled in < 0.4 second)

Proteus Industries Inc. has announced the release of WeldSaver, a flow controller created specifically to speedily shut down coolant flow when weld tips are lost from automated welding systems. Tip loss is a frequent and unpredictable interruption of production on automated welding lines. Without a tip, coolant is sprayed around the weld cell and across the work piece. If the weld controller is not shut down, damage to the welding system is likely, and a vital part can be passed to the next station without its full compliment of welds.

"We learned of the need for a specialized solution for this widespread problem by listening to our customers", said Jon Heiner, founder and president of Proteus Industries Inc. "We came to share their view that adaptation of conventional flow sensing and switching principles would not meet the exacting requirements of the automated welding line."

At the heart of WeldSaver is a uniquely sensitive differential flow sensor which responds instantly to the dramatic pressure changes which occur in the flow circuit when a weld tip is lost. The ratio of the rotational frequencies of two paddle wheel sensors is monitored by WeldSaver's microprocessor. If the ratio exceeds a preset value, an alarm signal is transmitted to the weld controller. A built-in pinch valve is triggered by the alarm signal, slamming shut both inlet and return flow lines in less than 1 second from the moment of tip loss.

Proteus Industries Inc.'s WeldSaver ­ a flow controller

"We evaluated several novel means of sensing tip loss, but none of them provided the unique freedom from pressure surges, temperature changes and fluctuating flow rates that are characteristic of WeldSaver's D² double differential flow sensor," explained Mark Nicewonger, VP of Technology for Proteus. "The only effect that will cause an alarm response is a rapid loss of flow between the two sensors. Weld tip loss is the overwhelming cause for such a loss."

WeldSaver displays flow rate directly in GPM or LPM on its built-in digital display, which also flashes the message "CAP OFF" when a tip is lost, giving operators immediate information on the cause of line shut down. Its keyboard allows precise selection of the low flow value at which to shut off the weld process, and provides local control of the pinch valve.

WeldSaver is available in 24VDC, 110/230 VAC and DeviceNet versions, providing easy retrofit in existing installations and capability for tomorrow's networked control systems. The unit can be mounted in horizontal or vertical orientations. The combined sensor/controller/valve unit is mounted to a cast aluminum manifold, which allows permanent hose connections. The controller unit can be separated from the manifold for re-calibration or test by the removal of only two screws.

"Reliability in the rugged environment of the automobile fabrication and assembly plant is no less demanding than that required by our users in semiconductor and medical therapy equipment applications," adds Heiner. "We have leveraged our experience in these zero tolerance fields with our sensor networking skills to create a controller that provides unequivocal detection of the loss of a weld tip, while adding new control potential."

"WeldSaver's performance has been established by an independent testing laboratory and its ruggedness verified through accelerated life testing. Feedback from in-field testing at multiple North American locations has generated valuable improvements which have been incorporated in production units."

Multiple units have been under test for several months on main assembly lines at:

General Motors:Oshawa, Ontario; Hamtramck, Michigan; Kansas City, Missouri.

Ford Motor Co.:Chicago, Illinois.

Toyota Motor Corp.:Georgetown, Kentucky; Fremont, California; Burnnaston, Derbyshire.

Isuzu Motors:Layfayette, Indiana.

Prices range from £1,250 to £2,000 depending on switching and system communication requirements. Volume discounts are available. Production shipments are scheduled for December 1997.

For further information contact Bob Eddiestone, Sales Manager, UK. Tel: +44 (0) 1282 415477; Fax: +44 (0) 1282 415477; E-mail: bob_e_Jpk@compuserve.com