Robots tending laser welding process

Industrial Robot

ISSN: 0143-991x

Article publication date: 1 February 2000




(2000), "Robots tending laser welding process", Industrial Robot, Vol. 27 No. 1.



Emerald Group Publishing Limited

Copyright © 2000, MCB UP Limited

Robots tending laser welding process

Robots tending laser welding process

Keywords: Robots, Laser welding, Thermal imaging

Two ABB robots installed at Laser Welded Blanks Limited of West Bromwich, have successfully completed 12 months of service-free operation and are now set to move up a gear into full time operation - 24 hours a day, seven days a week.

The robots are part of a sophisticated production line installed in 1998 as a joint venture between Steel and Alloy Processing and the French steel maker, Sollac. Laser welding sheet metal allows car panel components, such as door inners, to be made up from material of different thicknesses so that strength and rigidity can be tailored more accurately to suit the design requirement.

The process is more cost-efficient than traditional methods and offers higher build quality by reducing weight and providing a less complex construction. Demand for laser welded blanks has been confirmed with volume orders from Rover and Honda Manufacturing, accounting for virtually all of the available capacity. A contract to supply panel components for another new model car has been finalised recently and plans are well advanced for setting up an additional line at a separate location (see Plate 5).

The existing line is fully automatic with ABB robots loading sheets from two stacks into the positioning fixtures where they are clamped and presented for laser welding. At the heart of the process is a Trumpf 6kW CO2 laser, which delivers the beam to the welding head through an overhead gantry. A thermal-imaging camera checks the integrity of the laser weld. After welding, finished blanks are transferred to an output station for oiling and marking and if necessary, dimpling on the thinner side, to aid stacking.

Plate 5 ABB robots tending laser welding process

A trace from the thermal imaging camera is recorded automatically and any faults will show as an irregular temperature, which will raise an alarm at the control panel. The rejected blanks are then routed automatically to a scrap bin. As a further quality control measure, a sample joint from each bundle is cut out and subjected to a destructive test.

Each of the ABB robots is equipped with vacuum grippers for the handling of sheet metal blanks. Fully integrated within the process control, they both operate continuously in synchronisation with the laser process. Currently the line is tooled to produce up to 11 variants against three main customer programmes. Depending on the product, up to six blanks can be loaded at a time and each welding cycle takes around 40 seconds. For a typical production order the process can produce over 3,000 welded blanks within an eight-hour shift.

For further information contact Jane Attwood, ABB Flexible Automation Limited, Auriga House, Precedent Drive, Rooksley, Milton Keynes MK13 8PQ, UK. Tel: (+44) 01908 350300; Fax: (+44) 01908 350301.

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