Spot Welding
Questions and Answers
Weld schedules are available in the Resistance Welding Manual and AWS Standard C1.1 for many of the most frequently used materials. The information commonly provided is the proper electrode design, size and material. The weld force, weld time and weld current are also published. The minimum distance between welds is usually listed and the expected nugget or button size is shown. Tensile properties frequently are also published. Other sources are the Tuffaloy and CMW Catalogs.
A weld schedule is an instruction to set up a resistance welder for a given job. It includes all of the specific settings of the machine, control settings, tools, electrodes, forces, times, rates and all other pertinent data related to a job. It also includes the information about the part, including material, thickness, number of welds, weld locations, quality requirements, and precleaning. This information is stored and can be used to set up the job on it’s next run. It also can be used as a ground zero if parameters have changed and you want to go back to when the job started.
Resistance welding over a lip, in a corner, or in a box might be a perfect application for a double bend electrode.
Above is a sketch showing an example of a double bend electrode welding in a tight area. There are many applications like this that a double bend full size electrode or double bend shank and cap will allow you to reach an otherwise difficult location to weld. Double bends can be water cooled to increase life. Double bends come in many offsets and sizes as shown below.
DOUBLE BEND ELECTRODES
Reference: RWMA - Resistance Welding Manual 4th Edition
SINGLE AND DOUBLE BENDS CAN REACH THAT EXTRA DISTANCE IN RESTRICTED AREAS
Sometimes we have to reach inside a box or over a feature in a part that stretches our imagination. A double bend electrode might be the answer but a single bend electrode might also get us that extra distance. Both can be water cooled and deliver good force into restricted areas.
Reference: RWMA - Resistance Welding Manual 4th Edition
Electrodes are available in many sizes and shapes to fit most needs in industry. To choose many considerations come to mind. The first decision would be full size vs cap electrode. Are you a job shop or highly automated usually decides this.
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