Electrodes

Questions and Answers

The size 4 and 5 designate the body size of the electrode. A #4 electrode has a ½” body diameter with a 3/16” face diameter. A #5 electrode has a 5/8” body diameter with a ¼” face diameter. These are sizes established by the Resistance Welding Manufacturers Alliance (RWMA) and are published in Bulletin 16 Section 18. All manufacturers produce to these standards here in the USA. There also is a size 6 and 7.  Size 7 is rarely used in cap form.  The charts below show data for RWMA caps and full size electrodes.

Read more ...

Generally all spot welding electrodes are made from a copper alloy. During the resistance welding operations if their tensile strength is exceeded they will bend or collapse and fail from the mechanical force being exerted on them. RWMA Fig 18.3 in the RWMA Manual 4th Edition, shows the relationship of electrode weld face size, applied force and maximum capability.

Read more ...

Generally all spot welding electrodes are made from a copper alloy. During the resistance welding operations if their tensile strength is exceeded they will bend or collapse and fail from the mechanical force being exerted on them. RWMA Fig 18.3 in the RWMA Manual 4th Edition, shows the relationship of electrode weld face size, applied force and maximum capability.  Similar information is shown in the following table.

Read more ...

Resistance welding tapers are precision tapers for attachment of electrodes to resistance welding holders. They are meant for quick and easy attachment and removal. If the weld forces used in the application are excessive for the size of the taper, the male taper can be driven into the female taper and ruin the tooling. Electrode removal may become difficult or impossible and further use of the holder is compromised. RWMA Fig 18.3 in the RWMA Manual 4th Edition, shows the relationship of electrode weld face size, applied force and maximum capability.

Read more ...

Heat balancing is adjusting heat input so that the nugget forms at the center or more importantly the faying surface. Resistance welding two different work piece materials will often cause the heat to build up in one before the other. The same is true if the thicknesses are unequal. This frequently leads to the nugget forming mostly in the hottest side of the part instead of at the faying surface.

Read more ...

Have a Question?

Do you have a question that is not covered in our knowledgebase? Do you have questions regarding the above article? Click here to ask the professor.