Implementation of laser welding for lamp leads

Abstract

Lead wires are the conductors that supply electricity to the filaments and arc tubes of lamps [1]. Lead wires consist consist of at least two conducting wires of different compositions and sizes. A typical representation of lead wires is shown in Figure 1. Different compositions and sizes are required to meet the various requirements inside and outside the lamp as well as through the hermetic seal with the outer envelope of glass or quartz. Previously, these wire combinations were percussively welded via capacitor discharge welders; this process was speed constrained and produced rough welds. In the 1970’s, single beam laser welding was introduced; this process produced lopsided weld joints due to energy input into the joint from one side only. In 1986, GE Corporate Research & Development developed a split-beam fiber-optic technology for high energy pulsed neodymium (Nd): yttrium-aluminum-garnet (YAG) lasers [2]. This technology enables energy to be delivered to more than one side of a workpiece. Lead-wire welds made with a dual-beam fiber-optic system proved to be smoother and stronger, and speeds were increased. Currently two systems have been in successful production for over two years.Lead wires are the conductors that supply electricity to the filaments and arc tubes of lamps [1]. Lead wires consist consist of at least two conducting wires of different compositions and sizes. A typical representation of lead wires is shown in Figure 1. Different compositions and sizes are required to meet the various requirements inside and outside the lamp as well as through the hermetic seal with the outer envelope of glass or quartz. Previously, these wire combinations were percussively welded via capacitor discharge welders; this process was speed constrained and produced rough welds. In the 1970’s, single beam laser welding was introduced; this process produced lopsided weld joints due to energy input into the joint from one side only. In 1986, GE Corporate Research & Development developed a split-beam fiber-optic technology for high energy pulsed neodymium (Nd): yttrium-aluminum-garnet (YAG) lasers [2]. This technology enables energy to be delivered to more than one side of a workpiece. Lead-wir...