1. Excessive ultrasonic energy
If the power is too high or the amplitude is excessive, the fabric absorbs too much heat, causing the non-woven material to melt through instantly. 
This often occurs with thin non-woven fabrics when using high-power machines that generate excess energy.

2. Excessive pressure setting
If the clamping force between the upper and lower molds is too high, the fabric is tightly compressed; heat cannot dissipate, causing the local temperature to spike and burn through the material.

3. Feeding speed is too slow
If the fabric remains in the welding zone for too long, it is subjected to continuous ultrasonic vibration and heat exposure, leading to melting and perforation.

4. Misalignment between the pattern wheel and the welding head
Inconsistent mold engagement leads to concentrated local pressure and heat accumulation at specific points, making it easy for the fabric to burn through at those locations.

5. Frequency instability and abnormal energy output
If the generator fails to automatically track the frequency, resonance shifts occur, causing a sudden surge in energy that instantly burns the fabric.

6. Fabric is too thin or has a low basis weight
Thin non-woven fabrics have lower heat resistance and are more prone to being melted through under the same energy levels.