The Resistance Welding Manufacturers' Association has adopted standards for tips
and styles of holders, segregated according to shapes and sizes. There are five standard
styles of electrodes.
Pointed- tapered from the full-diameter electrode shank to required size and with
a flat surface, holds its shape well, but is difficult to dress in the machine unless a
dressing tool of the exact taper is provided.
Flat- employs the full shank or stock size at the welding surface.
Dome- the dome tip is used for less precise work where easy dressing is of
advantage. The dome shape provides a greater approach to the flat surface of the work.
Offset- is used to make a spot weld closer to a vertical wall than is possible
with a straight tip. The offset of the tip should as slight as possible, as the electrode
force or the compression load at the center line of the electrode axis will tend to cause
bending of the tip. Since the tendency of the electrode is to skid or deflect as the
offset distance form the center of the electrode axis increases, offset tips should not be
used except when required.
Radius- is used for the welding of aluminum and for many other precise
applications because of the superior results to be obtained. The spherical surface is
easier to clean without removing from the machine, will withstand higher pressures with
less deformation and is more readily aligned in the holders.