A laser-welding system incorporating IRB 140 six-axis robots from ABB Automation Technologies, developed for manufacturing critical components for the next generation of particle accelerator, is “probably the most precise and demanding application of a standard robot ever devised,” according to Chris Moore, Managing Director of Garrandale Systems, designers of the system. The system was developed in collaboration with Ferranti Photonics for Accles and Pollock of Birmingham, which is manufacturing special, non-magnetic, stainless steel alloy tubing assemblies for the new Large Hadron Collider (LHC) for the European Organisation for Nuclear Research (CERN). Planned for completion in 2007, the LHC, located near Geneva, will be the largest particle physics apparatus ever built. The LHC accelerates two beams of particles in opposite directions within a 27km ring of superconducting magnets held at temperatures approaching absolute zero. Accles and Pollock, using the manufacturing system devised by Garrandale, is producing both âdipoleâ? and âquadrapoleâ? tube assemblies. Dipole tubes are used to bend the path of accelerating particle beams and to keep them on course, while quadrapole tubes are used to focus the particle beams for collision at detector points. Each variant of dipole and quadrapole tube is an extremely accurate and complex welded assembly, comprising a beam screen tube, cooling tube, cooling tube feedthroughs, beam screen fixed points, sliding rings, contact rings and cooling tube supports. Garrandale’s task was to design a manufacturing system and jig that could handle tubes in lengths of 15-18m long which have to be straight and accurate to extremely tight tolerances in all planes. Welding specifications are extremely demanding – on one detail alone the tube assembly requires 0.3 mm diameter spot-welds every 1mm in axial length. For the two particle accelerator rings that works out at 54,000,000 welds alone! Commissioned in March last year, the Garrandale system has operated faultlessly since it started operation for Accles and Pollock.
