Resistance spot weld
Applied to joint
Overlapping sheets — spot welds at interface
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Spot welding equipment
Pedestal and portable spot welders for sheet metal work.
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Description
A weld made by passing electric current through overlapping sheets clamped between copper electrodes. The resistance at the interface generates heat, forming a weld nugget. No filler metal is used. The most common resistance welding process.
In plain English
The classic spot weld -- two sheets squeezed between copper tips, a big pulse of current, and you get a weld nugget where the sheets touch. No filler, no gas, no arc you can see. Fast, clean, and automated in most cases. The automotive industry uses millions of these per day. The symbol is a circle -- in ISO System A it has a line through it, in ISO System B and AWS it is a plain circle. The diameter of the nugget is specified to the left.
Symbol position
Circle on the reference line. In ISO System A, a horizontal line passes through the circle. Arrow points to the accessible side.
Size notation
Nugget diameter 'd' to the left. Pitch (spacing) to the right if in a pattern. Number of spots may be specified.
Notation examples
ISO System A uses a circle with a line through it. ISO System B and AWS use a plain circle. The dimension notation is the same -- this is purely a symbol appearance difference.
Circle symbol. No distinction between System A and B. Nugget diameter, pitch, and number of welds specified.
System A: circle with horizontal line through centre. System B: plain circle (same as AWS). Nugget diameter 'd' to the left.
Common uses
- Automotive body panels and chassis components
- Sheet metal enclosures and cabinets
- Appliance manufacturing
- Light gauge structural connections
