The requirement for heat welding or cooling before welding in ultrasonic plastic welding depends on the product's plastic material.
Many people know that "Plastic parts can deform and shrink if ultrasonic welding is done without cooling," and therefore assume that all plastics should be焊接 after cooling. However, that's not necessarily true. Whether ultrasonic plastic welding requires hot welding or welding after cooling depends on the plastic material of the product.

The ultrasonic plastic welding machine for PC material exhibits excellent welding performance in the heat state.
For instance, with common PC materials, welding using an ultrasonic plastic welding machine in a heated state yields excellent results. Since PC is a type of thermoplastic with relatively strong thermal conductivity, it is often challenging to maintain sufficient heat in the weld for an adequate welding time. Moreover, as PC requires a relatively higher temperature to flow, if the parts are already in a heated state, less heat is needed for the flow process.

PP and PE materials offer excellent welding performance in cold conditions.
Contrary to PC, not all material behaviors are the same, such as with PP and PE. These materials are inherently softer and have a lower thermal conductivity. Consequently, they often exhibit good welding results in the cold state.

Parts made of absorbent materials should be heated and dried before welding.
Another scenario involves materials like PA that are easily absorbent. After absorption, more welding energy is required, and the release of steam can cause more excess material overflow, which can affect the welding seal integrity of the part. Therefore, parts made of absorbent materials should be heated and dried before welding. Alternatively, after injection molding, the parts should be stored in a sealed bag to isolate moisture from the air.

When welding plastic parts with an ultrasonic plastic welding machine, many factors must be considered.
When welding plastic parts with ultrasonic plastic welding machines, numerous factors must be considered. Prior to full-scale production, the temperature of the parts should be defined and tested, followed by determining the welding parameters to achieve stable and excellent welding results.

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