Ultrasonic Welding Process-​Ultrasonic Spot Welding

Ultrasonic Welding Process-​Ultrasonic Spot Welding

Date:Feb 26, 2021

Ultrasonic Welding Process-Ultrasonic Spot Welding

Ultrasonic spot welding will dominate in the future. For example, flat molds without weld groove processing must pass this welding (semi-finished products, thermoforming, blown film, large flat parts, etc.).


The ultrasonic welding head penetrates from the upper part to the lower part, and the heat generated after contacting the surface of the mold plasticizes and welds the material. The squeezed plastic flows upward and forms an annular protrusion.

Ultrasonic welding head can be used for spot welding and riveting.

The ultrasonic mold can be fixed by suitable clamps or clamping devices. The thickness of the welding head cannot exceed 8 mm. Spot welding can also be realized with a movable ultrasonic manual welding equipment (hand welding gun).

Ultrasonic spot welding is an assembling technique for two thermoplastics without a designed shaped hole and energy bar. Spot welding is suitable for parts with high strength requirements and large volume. Extrusion molding and connection of thermoplastic parts, complicated geometry and difficult to reach parts of the welding surface, most thermoplastic materials use suitable spot welding technology.

Ultrasonic spot welding from the welding tip to the end of the section, the plastic at the distal end is melted and flows to the welding head cavity with an annular arc, forming a convex annular step on the surface of the plastic part. Thereby connecting the upper and lower plastic parts. The standard plastic part structure requires that the diameter of the circular step of the distal plastic part is 3 times the material thickness, and the height of the distal end protruding step is 1.5 times the material thickness.

Ultrasonic spot welding forms a clean welding area, the appearance of one side is not affected, and the other side is a neat annular boss. The process is fast and does not require additional fasteners. Therefore, it is widely used in car spoilers and dashboards.

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