The quality of ultrasonic welding is not determined by a single factor but is influenced by various elements, including equipment performance, process parameters, product design, and fixture stability. Below are detailed explanations of the key factors:

1. Ultrasonic Energy Supply Specifications (Generator)

The ultrasonic energy supply unit is responsible for providing stable and controllable high-frequency vibration energy, which is the core of overall welding quality.

• Closed-Loop Control System (Recommended) #T-sonic iS Series, #iX Series
  ◦ Real-time monitoring of vibration frequency and output power
  ◦ Automatic compensation for load variations (e.g., material differences, temperature changes)
  ◦ Improves welding consistency and repeatability
  ◦ Effectively reduces defect rates
  👉 Compared to open-loop systems, closed-loop systems offer superior precision and advantages in high-precision and mass production processes.

2. Vibration Frequency & Amplitude (Frequency & Amplitude)

The vibration conditions directly affect energy transfer efficiency and melting behavior.

• Frequency (kHz)
  ◦ Low frequency (15–20 kHz): High energy, suitable for thick or fiber-reinforced materials
  ◦ High frequency (30–40 kHz): Precise and stable, suitable for thin or precision products

• Amplitude (Amplitude)
  ◦ Too low amplitude: Inadequate melting, insufficient welding strength
  ◦ Too high amplitude: Causes flashing, burning, or appearance damage
  👉 The frequency and amplitude must be precisely matched to the material characteristics and product structure. #T-sonic iS Series, #iX Series

3. Welding Pressure (Weld Pressure)

Welding pressure affects the concentration of energy in the molten area and the flow of plastic.

• Too low pressure: Poor contact, insufficient heat energy

• Too high pressure: Melted plastic is squeezed out, resulting in a thinner weld seam
  👉 Appropriate pressure helps form a uniform and strong weld interface.

4. Hold Time (Hold Time)

Hold time refers to the period of pressure applied after vibration stops to allow the plastic to cool and solidify.

• Insufficient time: The weld seam may not fully solidify and could detach

• Excessive time: Affects cycle time and reduces productivity
  👉 Correct hold time avoids weld retraction and internal stress issues. #T-sonic iS Series

5. Energy Control Mode (Weld Mode) #T-sonic iS Series, #iX Series

Different control modes can be selected during the welding process based on the needs:

• Energy Mode
  ◦ Automatically stops based on accumulated energy
  ◦ Suitable for products with slight material or size differences

• Time Mode
  ◦ Simple to control, suitable for stable mass production

• Distance Mode (Collapse/Distance Mode)
  ◦ Terminates based on the molten displacement
  ◦ Suitable for high-precision welding needs
  👉 Choosing the correct mode contributes to welding consistency and quality control.

6. Weld Interface Design (Energy Director)

The design of the welding structure greatly affects the quality.

• Energy Director (Energy Director) concentrates ultrasonic energy

• Common forms: triangular, semicircular, stepped

• Size and position need to match the material and product thickness
  👉 A good energy director design can shorten welding time and improve welding strength.

7. Fixture Stability and Positioning Precision (Fixture)

The fixture is a key element in ensuring welding consistency.

• Poor positioning leads to energy loss

• Insufficient rigidity can lead to resonance or misalignment

• The fixture must ensure uniform force distribution across the workpiece
  👉 High-precision, rigid fixtures help stabilize welding quality.

High-quality ultrasonic welding comes from stable energy output, precise parameter control, good product design, and a reliable fixture system. A closed-loop control device, combined with the correct process settings, is crucial to ensure welding quality and stable mass production.