Industrial Applications Learning Activities View Slides; Read Notes, Listen to lecture Do on-line workbook Lesson Objectives When you finish this lesson you will understand: Selected Industrial Applications will be reviewed Keywords

Portable System Portable systems or welding guns are used where considerable mobility of the welder is required. Traditionally, these welding guns were hand held, although recently have been shown to be highly adaptable to robots. Older systems use a remote transformer and controller. Cables carry the secondary current to the welding gun. Because high power losses are associated with these cables, transformers with excess power ratings must be used with welding guns. For example, if the application called for a 30 kVA machine and maximum cable losses could be 5 kVA, a 35 kVA transformer would be specified. This raises the costs associated with the portable gun and creates a need to cool the cables to dissipate the heat caused by the cable losses. Recently integral transformer guns have become popular. These units have an advantage in that the welding transformer is actually contained within the gun. This greatly reduces cable losses, as the cables are now only required to carry line voltage and current. The transformers can be smaller, and there is no need to cool the cables as before. Many older welding guns are “scissors-type” guns -- a hand-type variation of a rocker arm-type welding machine. Currently, however, C-type guns are gaining in popularity. These guns are a hand-held variation of direct action-type welding machines. In this case, the moving electrode is attached rigidly to the plunger of the power cylinder. C-guns have the same advantages over scissors guns as press-type machines have over rocker arm-type machines. [Reference: Automotive Manufacturing, April 1996, p.5, SAE]

Automotive Industry Resistance welding is a far more flexible method of joining metals, and it is applicable to a greater range of sizes, shapes and materials than is generally appreciated. The flexibility feature may be examined from two viewpoints. For each of the principal resistance welding processes, machines are available ranging in size from small bench type welding machines to large installations in which the process is incorporated in an automated system with computer controls. Also, many of the standard types of welding machines can be used for several different types of welds by making comparatively simple changes in the electrodes and tooling. As for size limitations, there are found, at the lower end of the scale, such examples as the welding of tiny alloy tips to fountain pen points and joining wires of 0.001-in diameter and, in the upper ranges, welding sheets and plates having total thickness of one inch or more, flash welding solid rounds over 8-in diameter and flash welding plate edges in lengths up to 40 ft in the manufacture of pipe. The automobile industry has utilized resistance welding to the utmost for bodies, frames, housings, levers, braces, wheels, seats, and such smaller parts as spark plugs and electrical system components. The above slide illustrates a resistance spot welding process in the automotive industry. [Reference: Automotive Manufacturing, April 1996, p.5, SAE]

Micro-Electronic Industry Weld Weld Welds Weld Series Opposed Parallel Gap Angular E1 E3 ac Series welding: Wires up to 0.040 in. and ribbons up to 0.015 in. thick x 0.050 in. wide can be welded in the series welding process with conventional equipment. Opposed-electrode welding: A necessary requirement in opposed-electrode welding is access for the electrodes to approach the workpiece from opposite sides. Relatively high forces are easily obtained in this configuration, which enhances welding of comparatively large-diameter wires. Parallel-gap welding: Parallel-gap welding is a method whereby a single weld joint can be made where only one side of the work is accessible. Angular electrode welding: The angular electrode configuration is the most important for construction of cordwood welded modules because of the accessibility it provides for interconnecting on a plane surface where access is only from one side and lead wire projections are to be joined. Step-series welding: In this type of welding, one electrode is in contact with the base metal while the other is in contact with the ribbon or wire being welded. Step series is used primarily on materials that cannot be welded by parallel-gap methods. Hot electrode (three): This process permits welding insulated wire without prestripping the insulation. The insulation is vaporized by the generation of heat at the point of weld. Hot electrode (two): Most common varnish-insulated wires and plastic-insulated wires may be welded without prior insulation removal. dc E2 Weld ac Step Series Hot Electrode (Three) Hot Electrode (Two) [Reference: Handbook of Electronic Package, p.4-4, 4-5, Happer]