New robot tool changing system from Stäubli for piercing and metal clinching operations

Citation

(2001), "New robot tool changing system from Stäubli for piercing and metal clinching operations", Industrial Robot, Vol. 28 No. 6. https://doi.org/10.1108/ir.2001.04928faf.008

New robot tool changing system from Stäubli for piercing and metal clinching operations

New robot tool changing system from Stäubli for piercing and metal clinching operations

Keywords: Rivets, Stäubli, Metals, Robots

Two recently developed techniques, self-pierce riveting and metal clinching, are becoming increasingly popular as alternative methods to spot welding for joining sheet metal, particularly in the automotive sector. In response to this demand Stäubli, the connection specialists, have developed a tool changing system for robot arms that can withstand, reliably and safely, the high and pulsating pressures generated during these processes.

The MPS 360/HP is the latest addition to the well-established range of tool changing systems available from Stäubli. The facility to change automatically from, for example, a welding gun to a rivet gun or flange tool increases the utilisation of each robot arm and can often eliminate the need for additional investment (see Plate 8).

The MPS 360/HP is directly mountable on the robot flange in accordance with ISO 9409-1 A125 or A160. Locking and unlocking are controlled by compressed air and the clean break, flush face fluid couplings are designed to work on an extremely short stroke, minimising changeover times. The ability to handle payloads of up to 360kg is a distinct advantage over competing systems.

Plate 8 The MPS 360/HP is the latest addition to the range of tool changing systems at StÌubli

Automatic, clean break connections are made for air, water, electrics and data systems however it is the hydraulic connections that gives the 360/HP the ability to work with self-piercing guns and metal clinching tools. 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 are built to withstand the pulsating pressures encountered during the piercing process.

Self-pierce riveting technology was used for the first time in the automotive sector on the aluminium body for the Audi A8. The method produces a joint with 30 per cent higher strength than spot welding while requiring a significantly lower amount of energy. It can be used to join similar or dissimilar metals of any thickness, even joints between several layers are possible. By using a semi-tubular rivet in a single, low-noise and emission-free operation, a positive leak proof joint is made. The rivet pierces through the upper material and deforms on the die side making a secure joint. The system is readily automated, only a low level of operator skill is required, no pre-drilling or piercing are needed and the joint produced is easily inspected for quality.

In contrast, metal clinching produces a joint without the need for a secondary fastener. The sheet metal is pressed together to produce a cold reform which holds the layers securely together. By using a punch-die combination, a joint similar in form to a press-stud is produced. Multiple thickness of steel, aluminium and other non-ferrous metals can be joined by clinching, a reliable, efficient and environmentally-friendly process.

Stäubli MPS 360/HP robot tool changers are currently in use on both piercing and clinching activities as well as for many other robotic tool changer applications in the automotive sector and elsewhere. Installations at Audi, BMW and Daimler Chrysler are proving the capabilities of this new system. The MPS 360/HP and Stäubli's connection expertise are increasing the scope and potential for these new metal joining processes, especially in the automotive sector where the trend away from steel towards aluminium and light alloys is becoming well established.

Stäubli Connectors Division are specialists in providing solutions to all coupling requirements. Manufacturing is based in France and Germany with offices across Europe, North and South America and the Far East. The UK base is in Telford.

For additional information contact Craig Forrester, UK Sales Manager, Connectors Division, Stäubli Unimation Ltd, Stafford Park 17, Telford, Shropshire TF3 3DG, UK. Tel: +44 (0)1952 292148; Fax: +44 (0)1952 290057; E-mail: connectors.uk@staubli.com; Web site: www.staubli.com