Protect welders when weldgun caps are lost

WeldSaver protects operators and welding system when weldgun caps are lost.

Cap loss signalled to weld controller in < 0.4s prevents bad welds.

Complete water shut down in < 1.0s reduces water hazard and inconvenience.

Created by Proteus Industries Inc.

to overcome the challenges of monitoring cooling flows in robotic welding systems, the WeldSaver series of flow controllers can interrupt welding operations within 400ms and shut down coolant flow in less than 1s when a weld cap is lost.

The loss of a weld cap can cause frequent and unpredictable interruption of production on automated welding operations.

Without a cap, coolant is sprayed around the weld cell and across the work piece.

Water accumulating on the floor creates a safety and health hazard.

If the weld controller is not shut down quickly the next attempted weld could damage weld gun components.

A vital part can be passed to the next station without its full compliment of welds.

The WeldSaver was developed to answer the specific control requirements of robotic resistance welding users.

"We learned of the need for a specialised 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." "Yesterday's solutions utilising thermal and mechanical flow sensors were becoming too slow to stop welding operations before the next weld was attempted.

When their sensitivity was 'tweaked' to increase sensitivity, frequent false alarms became more disruptive than real cap loss events." At the heart of WeldSaver is a uniquely sensitive differential flow sensor that responds instantly to the dramatic changes of flow velocity occurring in the flow circuit when a weld cap is lost.

WeldSaver's microprocessor continuously monitors acceleration of the inlet and outlet flow paths.

When a weld cap is lost, an alarm signal is transmitted to the weld controller.

Simultaneously an included pinch valve is triggered, slamming shut both inlet and return flow lines in less than 1.

WeldSaver's cap loss algorithm is usable in circuits flowing up to 50 litres/min.

Flow sensor ranges are selected for different control tasks, to provide the fastest and most reliable detection and shut down with the lowest possible pressured drop.

The WeldSaver CO (Cap Only) version is optimised for monitoring the circuit including only the weld caps at flows up to 11 litres/min.

WeldSaver WR (Whole Robot) allows monitoring of cap, transformer and kickless cable circuits with a total flow of up to 30 litres/min.

For the very high flows required for resistance welding of aluminium, WeldSaver HF (High Flow) provides capability to control flows of up to 50 litres/min.

The HF version has also found wide use in monitoring coolant flow to multiple fixed tools and on body framing tools.

WeldSaver provides a bright indication of actual flow rate in litres/min on its built-in digital display.

This display also flashes the message "CAP OFF" when a cap 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.

Equipped for 24 V-DC operation, WeldSaver allows several control and interfacing options.

In the standard version a single 'OK-to-Weld' relay output is provided.

Options provide for separate relay outputs for Cap Loss and Low Flow conditions, remote control of the water ON/OFF status, and selection of logic levels compatible with all robot controllers.

A DeviceNet(r) version is also available.

The unit can be mounted in horizontal or vertical orientations.

"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 cap, while adding new control potential." WeldSaver was introduced to North American automotive manufacturing market in 1997.

Feedback from in-field testing at multiple locations has generated valuable improvements in hardware and software capabilities.

Today WeldSaver is in use in more than 30 primary Tier 1 manufacturing operations world-wide.

Proteus Industries' flexible manufacturing process allows WeldSavers to be configured to exact physical and electrical interface requirements of each customer.

WeldSaver is CE marked, and UL listed.

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