How to Choose the Correct Material for Ultrasonic Tool Head?

Ultrasonic tool head acts as an acoustic waveguide or transformer, amplifying and focusing ultrasonic vibrations onto the workpiece. The ultrasonic tool head stretches and contracts in length like a spring during plastic welding. For example, a 20 kHz tool head is typically a half wavelength long resonant rod, with its molecules constantly expanding and contracting 20000 times per second.

That's why it's important to consider materials with a good combination of acoustic and mechanical properties when manufacturing ultrasonic tool heads. The following three materials are used to manufacture ultrasonic tool heads due to their fatigue strength, acoustic properties, and surface hardness.

 

 

Titanium:

 

Titanium is the preferred material for manufacturing ultrasonic tool heads because it has good fatigue strength, excellent acoustic properties, and good surface hardness, and is used in plastic welding, metal welding, and food packaging.

Titanium tool heads can be brazed to the surface of titanium or coated with materials such as hard alloys, nickel, or Teflon. Suitable for applications that require high amplitude and harder surfaces.

 

Aluminium:

 

Due to its relatively low cost and ease of processing, aluminum is often the preferred choice for ultrasonic resonators with low stress and minimal impact/wear/erosion.

Aluminum has excellent acoustic properties, and large tool heads are usually made of aluminum.

Due to its relatively low cost, it is easy to obtain a wide range of raw material sizes, making it the best choice for making prototype tool heads.

Fast and easy processing, reducing delivery time and labor costs.

Aluminum has poor surface hardness and moderate fatigue strength, making it unsuitable for long-term, high wear production applications. However, aluminum tool heads can be coated or electroplated with soft nickel, soft chromium, and anodized to help alleviate these issues.

 

 

Steel products:

 

After heat treatment, steel has excellent wear resistance due to the presence of a large amount of carbides in its microstructure, and can be applied to ultrasonic metal welding joints, plastic sealing gaskets, and insertion gaskets.

Due to its hardness, steel tool heads are more brittle and are typically used for low amplitude applications.