AMP - Advanced Manufacturing Park

Joining

TWI- Friction Stir Welding
In friction stir welding (FSW) a cylindrical, shouldered tool with a profiled probe is rotated and slowly plunged into the joint line between two pieces of sheet or plate material, which are butted together. The parts have to be clamped onto a backing bar in a manner that prevents the abutting joint faces from being forced apart.

Frictional heat is generated between the wear resistant welding tool and the material of the workpieces. This heat causes the latter to soften without reaching the melting point and allows traversing of the tool along the weld line. The plasticised material is transferred from the leading edge of the tool to the trailing edge of the tool probe and is forged by the intimate contact of the tool shoulder and the pin profile. It leaves a solid phase bond between the two pieces. The process can be regarded as a solid phase keyhole welding technique since a hole to accommodate the probe is generated, then filled during the welding sequence.

Equipment at TWI's Yorkshire Technology Centre includes;

• High Force Multi Axis FSW machine
• Precision Spindle FSW Machine
• RoboStir Robotic FSW Machine

www.twi.co.uk/content/twi_yorks_fsw.html

TWI - Fibre Lasers
With a power of over 7kW and a wavelength close to that of the Nd-YAG lasers, the Ytterbium fibre laser installed at TWI Yorkshire offers great potential in terms of welding and cutting operations. Couple this with a highly versatile 6-axis robot manipulating the laser delivery head, and this potential becomes an extremely powerful processing tool available for research and production trials.

Fibre lasers offer the advantage on being easily scalable - the basic set-up of the equipment is fairly compact, and increases in power are achieved simply by adding more of the low power units, with no obvious limit to the power, other than money. Today, the output power of a fibre laser far exceeds that available using Nd:YAG laser technology, whilst also offering a better beam quality. In fact, fibre laser power and beam quality are fast approaching, and in certain cases already even exceeding, those of CO 2 lasers.
www.twi.co.uk/content/twi_yorks_fibre.html