Process control improvements in pulsed Nd:YAG laser closure welding of electromechanical relays
The pulsed Nd:YAG laser welding process is often chosen today for closure welding of small hermetically sealed electrical devices. This is because it is a high power density welding process that can minimize total heat input and therefore is less likely to damage heat sensitive components. The effect of the pulsed Nd:YAG laser welding parameters on the incidence of glass-to-metal seal cracking and on the weld fusion zone dimensional parameters for an electromechanical relay has been determined. Fluctuations in weld penetration in production relays have been attributed to variability in sharp focus positioning. A large increase in blowholes and porosity in the fusion zone has been traced to the inadvertent substitution of 304 stainless steel for 304L stainless steel header material. The blowholes and porosity are thought to result from a carbon-oxygen gas reaction in the weld pool due to the presence of a 4/percent/ oxygen atmosphere and the increased carbon content of the 304 stainless steel. A technique using diamond apertures to measure laser spot size has been developed and has proved useful in determining the effect of the process control parameters on the actual workpiece irradiance. 4 refs., 8 figs.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (USA)
- DOE Contract Number:
- AC04-76DP00789
- OSTI ID:
- 5098171
- Report Number(s):
- SAND-87-1574C; CONF-880547-2; ON: DE88006275
- Country of Publication:
- United States
- Language:
- English
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