Spot welding is a type of resistance welding used to weld metal sheets together. Also known as resistance spot welding, it applies external force at singular points or spots, to press and join the surface area. This older form of welding metals to sheets is usually done by passing an electric current without a filler.

Resistance spot welding is very important in the manufacturing industry. It is fast, simple, and cost-effective. But its reliability depends on several variables such as the careful control of pressure and electric current. Deviating from specified parameters causes sub-standard welds resulting in an unsatisfactory finished product. Poor products adversely affect the customer’s satisfaction and the manufacturer’s revenue.

One of the quality-control measures for a spot weld is its joint strength. Due to the growing trend of using light materials, mild steel sheets are now replaced with aluminum and other alloys. Difficulty in welding these materials lead to the development of ultrasonic spot welding.

This process is more efficient in joining similar and dissimilar solids. The high-frequency vibratory energy produces a solid-state weld when the components are subjected to pressure. This is applicable for both thin and thick sheets of alloys, where the joint is created without melting the base.