ABB robots welding 4 x 4 vehicle frames for Thompson Chassis

Citation

(1998), "ABB robots welding 4 x 4 vehicle frames for Thompson Chassis", Industrial Robot, Vol. 25 No. 6. https://doi.org/10.1108/ir.1998.04925faf.001

ABB robots welding 4 x 4 vehicle frames for Thompson Chassis

ABB robots welding 4 x 4 vehicle frames for Thompson Chassis

Keywords ABB, Automotive, Robots, Welding

Thompson Chassis, a division of UPF, one of Europe's leading manufacturers of vehicle structures for the automotive industry, has commissioned a new 15-station automated assembly line at its Wolverhampton facilities (see Plate 1).

The new line, which incorporates 20 ABB IRB 1400 MIG welding robots and linked transfer system, was designed and installed by ABB Flexible Automation of Milton Keynes under a £2 million turnkey contract awarded in 1997.

The new line will be used to produce fully-welded vehicle chassis frames for Land Rover. It draws on Thompson Chassis experience with its first robot assembly line, commissioned during the early 1990s for production of chassis for the Vauxhall/Opel Frontera.

Thompson Chassis has produced vehicle chassis frames since 1908 when it won its first contract from Rolls-Royce Motor Cars. Whilst also continuing as a supplier to Rolls-Royce ­ Thompson Chassis is currently supplying sub frame components for the new Silver Seraph ­ the company's order book now includes a variety of trucks, taxis as well as leading British built 4×4 vehicles.

Production for Land Rover includes the Discovery chassis using dedicated welding machines installed in 1989. While these machines can match robot technology for speed and quality, they are generally more expensive and take longer to design and commission.

Plate 1 Part of the new welding line installed by ABB Flexible Automation at the Thompson Chassis factory in Wolverhampton

Robots are also inherently more flexible and easily updated for changes in component design, or if necessary re-programmed for different tasks.

Having proved the efficiency of using robots with the Frontera line, Thompson Chassis were able to draw up their requirements for an additional line to produce chassis for the next generation of Land Rover Discoveries.

ABB Flexible Automation won the contract to supply the line in open competition with other European system builders. As well as price, one of the main deciding factors was ABB's ability to offer a turnkey package for the complete line.

"As far as we are concerned our welding application could be handled by most makes of robot. Our priority was to choose a supplier capable of integrating the automated transfer with the robot cells and deliver consistent quality throughout the process", said executive director Neil Garner.

The new Land Rover line comprises 14 assembly stations, including two turnover positions and a final inspection bay where the completed frame is measured by an ITP co-ordinate measuring machine. The art in manufacturing vehicle chassis frames is in knowing how to control the process and make allowances for movement by contraction, working to very precise geometrical tolerances.

The process starts with the assembly and tack welding of the basic ladder arrangement. A walking beam transfer mechanism then moves the frame through a series of welding operations as some 200 components and 3,000 inches of weld are added to the chassis as it progresses down the line.

There are five robot cells each containing four IRB 1400AW robots each equipped with ABB's new generation Arcitec integrated welding system. The line is designed to manufacture up to 20 frames an hour. Initial verification of the line was undertaken by using Autocad computer-aided design software to test the sequence of build, verify robot reach and create a programme to simulate the operation of each cell.

The order for the project was awarded in February 1997. Most of the equipment was installed by early 1998 and target completion for pre-production manufacture achieved by April. Apart from the site preparation, foundations and power take off points, ABB Flexible Automation undertook the integration of all the automation as a turnkey project. Thompson Chassis provided all the jigs and fixtures, the design of which will remain closely guarded secrets.

ABB's success in winning the contract came at an opportune time as Thompson Chassis embarked on additional investments in robot welding to improve productivity. The first of these was a £600K project to automate the spot-welding operations of chassis side rails. Each rail has over 200 spot welds within the box section's internal reinforcements. The process, which was previously carried out manually is now performed by two cells of three heavy duty IRB 6400 robots equipped with spotwelding attachments.

A third ABB installation came as the result of Thompson Chassis's continuing links with Rolls Royce Motor Cars and new contracts to supply front and rear sub frame components for the new Silver Seraph. ABB supplied a single robot cell, commissioned earlier this year for MIG welding the sub frame components. The robot serves two windows with two sets of fixture at any one time. Each fixture is unloaded and replenished with new parts while the robot is welding components in the opposite window.

By specifying ABB robots, Thompson Chassis has achieved savings in training, and maintenance, spares and service support. Manual welders are being replaced by operators skilled in programming its robots.

For further information contact Jane Attwood, ABB Flexible Automation Limited, Auriga House, Precedent Drive, Rooksley, Milton Keynes MK13 8PQ. Tel: +44 (0)1908 350300; Fax: +44 (0)1908 350301.