British Steel proposes laser welded tailored blanks to UK car industry

Citation

(1998), "British Steel proposes laser welded tailored blanks to UK car industry", Industrial Robot, Vol. 25 No. 1. https://doi.org/10.1108/ir.1998.04925aab.009

British Steel proposes laser welded tailored blanks to UK car industry

British Steel proposes laser welded tailored blanks to UK car industry

The first laser welded tailored blank facility in the UK is now operational. Installed by British Steel Distribution (BSD) at its specialist automotive processing centre in the West Midlands, the £1.7 million facility is currently making prototype and pre-production panels.

The company hopes to receive orders for volume production tailored blanks in the near future. "We're currently making development and prototype panels for a number of companies. We expect to win a volume contract soon, maybe even within a week", comments Steven Norgrove, general manager. As soon as an order for production volumes is confirmed, BSD will purchase laser welding equipment matching the requirements of the customer and his panels, Norgrove adds.

Flexibility is the key feature of BSD's first tailored blanking facility. This led to the choice NV Balliu as supplier of the first laser welding machine. "We wanted a machine that would be capable of doing any kind of panel fitting within a certain size range", Norgrove explained. Balliu, he adds, has a track record in this area.

The laser welder that is now running is capable of a maximum finished blank size of 2m × 4.25m. Each blank can be made up of four different blanks with three welds holding them together. Blank thickness ranging from 0.5mm to 3.2mm can be handled in the cell. Blanks of different thicknesses can be welded together. Laser welding can be used to join blanks whose thicknesses vary by a factor of three to four, claims John Barker, at Balliu's UK office.

Designed for automated operation, the laser welding cell is equipped with two ABB IRb6 robots to load blanks to the welding table, and a Cincinnati Milacron robot for unloading finished panels. All safety precautions have been taken to allow the cell to operate unattended, says Norgrove.

The two ABB robots are mounted on tracks, one on either side of the table. Two stacks of blanks alongside each robot track provide several hours of autonomy. The robots handle the blanks using an end-effector fitted with suction cups.

The robots' first task is to present each blank to a guillotine located at one end of the work table. This prepares the edge which is to be welded. The robots then place the blank on the table which delivers it to the welding station. Clamps built into the table ensure that the blanks to be welded are precisely aligned with a minimum gap between the edges. A maximum fit-up gap of 0.02mm can be tolerated, says Barker. The condition of the flat surfaces is not so important.

The welding station uses a 6 kW Rofin Sinar laser situated adjacent to the welding table. The welding head is mounted on a gantry above the work table. The speed of welding is adjusted according to the specific weld to be made. It can vary up to 8m/minute. The average speed used by BSD at present is 5.5-6m/minute. The welding head is fitted with a Jurca weld monitoring system to ensure the consistent quality of welds.

BSD currently runs batches varying from one or two panels up to 500. Changeover from one batch to another takes only about 15-20 minutes, Norgrove says. The loading of the robot programs is done off-line. However, some adjustment to the grippers may be necessary, he explains. The stacks of blanks may also require changing.

Every car manufacturer in the world is interested in using tailored blanks, reported Norgrove. New models due to be launched from 2000 onwards will incorporate them more and more, he added, because of the weight advantages they provide.

To support customers moving towards new lightweight car concepts, BSD has established an Automotive Engineering Group based in Coventry close to the UK's car manufacturers. This group, which now comprises a team of 22 technology specialists, is working with potential customers on new vehicle programs to demonstrate that the lightweight technology is ready to be implemented. "Fifty-five per cent of every car on the road is currently made of steel. We have a lot of reasons for hanging on to that business", explained Professor Jon King, who heads up the automotive group.

Based in Ghent, Belgium, Balliu produces a range of standard and special-purpose processing machines using either laser, plasma, water-jet or ultrasonics. It makes 70-80 systems a year, according to John Barker at Balliu's UK office, and has previously supplied four laser welded tailored blank facilities, one of which has been installed by Sollac, France's steel company. Balliu has subsidiaries in France, Germany, Italy, Australia and the USA, and worldwide employs 120 people.

British Steel Distribution's new automotive centre in full production

Balliu has also supplied BSD with the laser cutting system which has been set up alongside the laser welder. It incorporates a 1.7kW Rofin Sinar laser and cutting bed measuring 4m × 2m. It is currently supplying low volume and prototype blanks for Rolls Royce and Aston Martin cars.

The new laser welded tailored blank facility is part of a £13.5 million investment at BSD's automotive processing centre at Wednesfield which is supplying customers such as Honda, Rover, Toyota, Ford, Vauxhall, Jaguar and Nissan. The investment also includes a Fagor 600-tonne press blanking line, a Durmech 2m wide 25-tonne multi-strand blanking line, a Fimi 2m 25-tonne slitting line and a Rovetta 600-tonne press. A further investment of £13.5 million on the site will enable BSD Automotive Wednesfield to reach a production capacity of 250,000 tonnes per year by 2000.