Spot welding is the most commonly employed type of resistance welding. This method involves passing an electrical current through electrodes attached to two separate metal surfaces pressed together. This action generates heat that melts and fuses the pieces—forming “spot welds”—at one or more localized positions.
Below is an overview of spot welding, outlining how the process works, its advantages, and how it compares to alternative methods.
How Does Spot Welding Work?
The spot welding process relies on conductive heating. The resistance experienced by the applied electrical current generates heat that melts and—ultimately—fuses two or more individual metal pieces together.
Traditional spot welding operations employ the use of copper alloy electrodes, which hold the pieces in position and facilitate the flow of the current into the workpiece. Welders apply short bursts of electrical current that heat and fuse localized areas of the workpiece. Once fused, the current is no longer required. However, the electrodes continue to apply pressure to the workpiece until the melted metal cools and solidifies, forming a solid welded joint. The size and shape of the electrodes employed influence the size and shape of the welds achieved.
Advantages of Spot Welding
Spot welding provides many manufacturing advantages to industry professionals, such as:
- Faster and easier operations. Spot welding does not require special skills, a quality which lowers the amount of training needed for existing and potential employees.
- Lower material costs. The spot welding process does not require the use of flux or filler material to form a joint, reducing overall material costs for such operations.
- Safer working conditions. Spot welding operations do not use an open flame to create joints, which decreases the likelihood of burns or fires.
- Better accommodation of automation. Spot welding operations readily accommodate automation, resulting in faster and more cost-effective production operations.
Spot Welding vs. Other Welding Methods
Compared to other welding methods, spot welding offers many advantages (as outlined above). Here’s how the process compares to some of the alternative welding methods available:
- Compared to MIG and TIG welding: Spot welding operations are generally much faster than MIG and TIG welding operations. They also carry lower skill and experience requirements, minimal material demands, and a smaller risk of thermal distortion. However, while MIG and TIG welding operations take longer—often requiring additional processing to resolve thermal distortion and other surface finish issues—they generally produce stronger and more durable welds.
- Compared to Projection Welding: Spot welding is generally used for thinner workpieces and parts with corners. In contrast, projection welding is typically employed to produce welds on thicker materials and heavy-duty parts. The projection welding process simultaneously creates a larger quantity of stronger and more aesthetically pleasing welds than the spot welding process with less heat and pressure requirements. However, it requires the use of projections with the same height to achieve a strong joint and is not suitable for metals such as copper and brass.
Quality Spot Welding Equipment Solutions From Tec-Option
Founded in 1996, Tec-Option has since established itself as a premier supplier of quality product welding and assembly solutions. We offer a broad selection of automated welding systems—including spot welding machines—to suit a wide range of welding needs. If you need a durable, efficient, and cost-effective welding system, our experts can help you design, engineer, and assemble one to your exact specifications.
For additional information about our welding equipment solutions, contact us today.