Automotive supplier single-sources 360 welding robots

Citation

(2001), "Automotive supplier single-sources 360 welding robots", Industrial Robot, Vol. 28 No. 4. https://doi.org/10.1108/ir.2001.04928dab.005

Automotive supplier single-sources 360 welding robots

Automotive supplier single-sources 360 welding robotsKeywords: Robots, Welding, Motoman

The latest £1.6 million order for 68 robots and manipulators placed on Motoman Robotics (UK) by first-tier automotive supplier, TKA Chassis Tallent, Newton Aycliffe, brings the total number of Motoman welding robots on site to more than 360. It is by far the largest number of robots operating under one roof in the UK outside car plants. About 80 per cent are for arc welding, with the remainder devoted to spot welding applications.

In 1982, just three years after robotic arc welding became an established production technique, the first 11 Motoman robots were installed in a 20-station line for arc welding the Ford Sierra rear suspension arm, or wishbone. Two spot welding machines also formed part of the total installation.

At the time it was one of the most advanced facilities of its type in the world and formed the cornerstone of the entry by Tallent into the supply of automotive chassis/suspension products. The company was able to see Motoman equipment welding the Volvo 740 rear axle in Sweden and, in addition, it was known that other subcontractors to Ford were already using Motoman robotic welding.

For a manufacturer to source such a large number of robots from one supplier requires a considerable degree of trust on both sides, and the Tallent/Motoman relationship is an early and ongoing example of the modern business "partnership" approach. The personalities involved then and now are Bernard Robinson, chief executive officer, and Clive Wheeler, operations director, of TKA Chassis Tallent, and Mike Wilkins, the director of Motoman in charge of welding applications.

Motoman's multi-axis control software enables a 25 per cent reduction in cycle time compared with competitive controllers, as all axes receive their instructions simultaneously instead of in sequence and the robots may be controlled synchronously, which gives rise to a dramatic increase in productive time. Furthermore, highly evolved arc welding artificial intelligence within the controller simplifies programming, thereby maximising cell uptime.

Even the workpiece handling systems employ advanced technology. Developed at Motoman's European headquarters in Sweden and introduced to Tallent in 1991, the patented RM2 manipulator with full pneumatic and electronic sensing uses just one servomotor to drive component rotation at both stations as well as station changeover. Conventional systems use three motors to achieve the same result, which is more costly and less reliable.

Quality levels achieved by Tallent are remarkably high, thanks in part to the company's investment in effective washing of pressings and in blanking tools for trimming components to close tolerances prior to robotic welding. Maximum joint gap is precisely maintained at half wire diameter, typically 0.5 mm, and positional accuracy at the welding tip is + 0.8 mm with +0.5 mm repeatability. This obviates the need for seam tracking, which would impose an unacceptable time penalty in this highly competitive, mass production environment.

In 1987 the six-axis robot was introduced by Motoman, sporting the additional facility of arm rotation, allowing more complex welding routines to be performed. One spot welding robot and five MIG cells were installed for producing the Nissan Bluebird front suspension arm. The turnkey system, including tooling, welding equipment and programs, was put together and tested at Motoman Robotics (UK) in Banbury prior to installation at Newton Aycliffe (see Plate 3). In the same year. Ford asked Tallent to take over welding of the Transit rear axle, hitherto made in house, and further turnkey MIG cells comprising five robots were purchased.

A succession of robotic welding installations followed in the early 1990s, starting with a £2 million, 22-robot spot and MIG installation for welding the subframe and front suspension link of the Metro (subsequently renamed the Rover 100). Then in 1992, 16 MIG welding robots went in to a cell integrated by Pico for production of the Nissan Micra rear axle. At the same time, the first 100kg robots were delivered by Motoman to form a twin cell for spot welding Honda Civic and Rover 200 Series rear suspension arms. At the time they were the heaviest spot welds made by robots operating in the UK and were powered by 250 kVA transformers.

Plate 3 One of the 360 Motoman welding robots in action at the Newton Aycliffe factory of TKA Chassis Tallent

The next year saw the phased introduction of 24 MIG welding robots for producing the rear axles for two popular Ford models, the Fiesta and Escort.

Tallent continued to invest in the latter years of the 1990s, taking delivery of over 50 Motoman robots directly from the Japanese manufacturer, Yaskawa. They were mainly employed for a variety of projects for Nissan and Honda, the cells being integrated by specialist companies appointed in Japan. Motoman Robotics (UK) was responsible for service and technical support of these directly-supplied robots as well.

In addition, 15 twin Motoman robot cells were integrated by Lamb Technicon for MIG welding the Mondeo subframe, followed by 40 robots in standard MIG cells as well as spot welding units for other new products. In 1998, a further 21 MIG robots, together with one for spot welding and a further unit for cutting were supplied for work on Rover and Land Rover vehicles.

During 2000, another robotic welding project involving 68 Motoman robots brought the total number of units sourced from this single supplier to in excess of 360.

For further information, contact: Mike Wilkins, Sales Director, Arc and Cutting Systems, Motoman Robotics (UK) Ltd, 1 Swan Industrial Estate, Banbury, Oxfordshire OX16 8DJ, UK. Tel: +44 (0)1295 272755; Fax: +44 (0)1295 267127.