Robot arm automatic tool changers up output

Audi's A8 car plant's body-in-white shops said assembly flexibility has been significantly increased after fitting Staubli automatic tool changers to its 6-axis robots.

The use of Staubli automatic tool changers at Audi's A8 factory in Germany, has significantly increased the flexibility of the body-in-white production line.

They have also helped to reduce space requirements and investment in automation equipment.

Producing a range of different car models, based on one platform, demands an efficient, cost effective operation.

It places a significant demand on production tooling as it increases the number of tools needed in each robotic cell.

More tool changes could lower cell productivity.

Audi said that the use of Staubli automatic tool changers (ATC) had removed these problems and reduced the need for providing any additional investment in space or equipment.

* Automated plant, wide build variety - Audi's plant at Neckarsulm, Germany, produces the base models A6 and A8 in saloon and avant (estate) versions as well as higher specification variants.

The body plant for the A8 is automated.

Each processing cell has a number of 6-axis robots using several welding, riveting, hemming, gripping and glueing tools.

Staubli robot ATCs are used throughout.

* Under body - typical of ATC application is the under body production cell where four robots share 10 tools to spot weld and hold the panels.

There is the stud welding cell where eight tools are shared between four robots.

Tool changes on each robot arm are automated using Staubli ATCs.

Tool changer models 360 and 500, with payload capacity up to 500kg, are used on spot and stud welding guns.

Automatic, clean break connections are made for air, fluids, hydraulics and water, with power and data system connections being made simultaneously.

In standard form a maximum working pressure of 320 bar provides the power to operate each of the selected tools while the robust wrought steel construction and patented secure locking systems, either electric or pneumatic, are built to withstand the forces encountered during the process.

An electric option is also available which is particularly useful when compressed air is not available in the cell or a totally electric cell is required.

The modular construction of the 360 and 500 models allow individual connectors to be specifically selected for each application.

* ATCs save space - the ATCs enable the compression of several welding and riveting operations into one cell.

So the ATCs dramatically reduce the space required by minimising the total number of cells.

Their use also gives major benefits in terms of cell flexibility with any modifications to tooling or sequencing being easily assimilated.

Staubli said that Audi regarded the ATCs as being virtually maintenance free - just a visual check on wipe over being all that is required.

All of the tool changers are directly mountable on the robot flange and provide secure locking and unlocking of each tool used.

The locking unit is failsafe in case of power loss.

Fluid connections are made using Staubli clean break, non spill, flush faced couplings.

Electrical, signal and optical connections use products manufactured by a subsidiary company in the Staubli group, recognised as a leading specialist in electrical connections.

This gives Staubli the unique facility of having mechanical and electrical connection expertise in house.

In the Audi A6/A8 bodyshop, 500 tool changes are made each day.

Some of the Staubli ATCs have made over 2 million changes and are still working to an accuracy of 0.5mm.

* About Staubli - Staubli is an international family owned group founded over 100 years ago in Switzerland employing 3500 world-wide.

The Couplings Division manufacturing facilities are headquartered in France with additional manufacturing in Italy and Germany.

Offices are located across Europe, North and South America and the Far East; the UK base is in Telford.

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