What’s the difference between ultrasonic welding and electric resistance welding

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Welding is the process of joining two metals. The significance of welding is evident in the manufacturing of items such as phones, laptops, and vehicles.

Welding demands different levels of skill and precision, depending on the specific welding type and the skill level of the welder needed for the job. This article takes an in-depth look at the differences between two common welding methods: electric welding and ultrasonic welding.

Introduction to ultrasonic welding and electric resistance welding

Ultrasonic welding

Definition and Basic working principle: Ultrasonic welding is a high-precision technique that involves the use of ultrasonic vibrations to create a solid-state bond between materials. 

Application: Ultrasonic welding is utilized in various industries for applications ranging from automotive part assembly and electronics manufacturing to medical device production and packaging sealing.

Application of Ultrasonic welding

Electric resistance welding

Definition and Basic working principle: Electric Resistance Welding (ERW) is a welding method that achieves a permanent bond between metal components by subjecting them to an electric current, resulting in the melting of the metal at the connection point.

Application: Electric resistance welding is commonly applied in the manufacturing of pipes, tubes, and structural components for industries like construction, automotive, and aerospace, where strong, durable welds are essential.

Advantages and limitations

Advantages of Ultrasonic Welding

Precision and Accuracy: Ultrasonic welding offers exceptional precision, making it ideal for delicate applications.

Clean and Eco-Friendly: Embracing ultrasonic welding translates to an eco-friendly choice, as it refrains from emitting noxious fumes or sparking during the welding process and it doesn’t require additional materials like adhesives or solder.

Reduced Heat: Minimal heat generation means less distortion and damage to sensitive materials.

Limitations of Ultrasonic Welding

Material Compatibility: Limited to certain materials, primarily plastics and non-ferrous metals.

Thickness Restrictions: Works best with thin materials. It is worth mentioning that due to the development of technology, many manufacturers like us are working to make their ultrasonic welding equipment suitable for thicker welding materials. It is believed that the thickness of welding materials will not be a problem in the near future.

Equipment Cost: Ultrasonic welding machines can be expensive to acquire and maintain. Despite its higher initial cost, ultrasonic welding machine consumes significantly less energy than traditional welding. It eliminates the need for additional materials like bolts, thus reducing material expenses. Moreover, it is not labor-intensive, leading to a reduction in overall overhead costs.

Advantages of Electric Resistance Welding

Speed and Efficiency: ERW is known for its rapid welding speeds, making it suitable for high-volume production.

Strong and Durable: ERW creates strong and durable welds, ensuring structural integrity.

Versatility: It can be applied to a wide range of materials, including carbon steel, stainless steel, and more.

Limitations of Electric Resistance Welding

Heat Generation: ERW generates significant heat, which can lead to distortion and structural changes.

Equipment Complexity: ERW machinery can be complex and may require skilled operators.

Precision Constraints: It offers moderate precision compared to ultrasonic welding.

Key differences

  1. Heat generation

Ultrasonic Welding: Minimal heat generation.

Electric Resistance Welding: Generates significant heat.

  1. Precision and accuracy

Ultrasonic Welding: High precision and accuracy.

Electric Resistance Welding: Moderate precision.

  1. Material compatibility

Electric Resistance Welding: The materials suitable for e-resistance welding are mainly conductive metal materials, such as iron, copper, aluminum, and other materials, especially stainless steel. Metal materials with high thermal conductivity such as copper and aluminum are difficult to weld when their thickness increases.

Ultrasonic Welding: Ultrasonic welding can basically weld solid metals, such as aluminum, copper, gold, silver, etc., but does not contain metals that are too hard or too soft. For example, stainless steel is too hard and cannot be welded; if tin is too soft, the surface of the solder joint will easily High-frequency mechanical vibration causes edge fatigue damage, which is not conducive to welding hard and brittle materials. 

Selecting the right welding method

Ultrasonic welding and resistance welding are both prevalent welding techniques that vary in terms of the materials they weld, welding speed, duration, and quality, necessitating their selection based on specific requirements; ultrasonic welding finds extensive use in the small electronics and automotive sectors, while resistance welding is commonly applied in manufacturing and equipment manufacturing industries.

For example, Abhishek Das, senior research fellow at the Warwick Manufacturing Group (WMG) at the University of Warwick in the UK, said Ultrasonic welding is used in a variety of electric vehicles, including the Nissan Leaf and General Motors’ Chevrolet Volt, Spark and Bolt.

In contrast, high-temperature processes like electric resistance welding can expose a car’s battery to enough heat to melt or disrupt safety vents, compromise seals, or cause internal shorts in the battery. It can also cause more battery fatigue, compromising long-term reliability.


Consider these points when choosing ideal welding technique between ultrasonic welding and resistance welding:

There is no single welding method that can be deemed perfect, as each comes with its own set of pros and cons. Certain projects may necessitate fusion welding, whereas others might be better suited for solid-state welding.

The crucial factor lies in choosing the most suitable approach for the specific task at hand. This decision should take into account the metals being joined, the thickness of these metals, and the welding environment, among other factors.

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