Connect, no.143, July - August 2006, p.6
Nd:YAG laser welding of a stainless steel rotor casing
Control motors and electronic devices used in aerospace, automotive and electronic industries are normally encapsulated and hermetically sealed to ensure satisfactory performance. The devices contain magnetic or temperaturesensitive components and the joints need to be narrow, precise and with controlled penetration.
Welding often needs to be carried out in the strong magnetic field associated with the device, and the welding operation itself must not disturb the internal magnetic device. In addition, as the welding for encapsulation is normallythe last step in manufacturing, the weld is required to be high quality and should be free of porosity, spatter and surface oxidation. The magnetic fields within the device make it difficult to use arc or electron beam joiningprocesses due to the interference of the magnetic field with the electric arc or the electron beam.
Laser beam welding is one of the few processes that are not sensitive to magnetic fields. The low energy input, precise and non-contact aspects of laser welding are ideal for producing narrow welds for sealing miniature devices withelectro-magnetic and temperature sensitive components without part deformation or damage to the internal electronic components.
With a full range of laser facilities, TWI can develop laser welding procedures for applications using different encapsulating materials, manufacture low volume advanced prototypes and provide technical assistance during thetransfer of the developed procedures to industrial production.
For more information, please contact Dr Steve Shi.
E-mail: steve.shi@twi.co.uk
