What about the limitations of ultrasonic welding ?

Limitations of ultrasonic welding

Despite the ultrasonic welding has many advantages, but also have certain limitations, ultrasonic welding before select ultrasonic welding technology and ultrasonic welding plastic parts design, product design engineers must know the solutions for the limitations of ultrasonic welding, and through the reasonable parts design to avoid the generation of ultrasonic welding defects, improve the quality of welding.

1) Limitations of materials.

Ultrasonic welding can not weld all plastics, which is the biggest limitation of ultrasonic welding. Some plastics have good welding performance, some plastics have poor welding performance, and ultrasonic welding is generally only suitable for welding between a kind of or similar plastics. If two plastic parts are made of different materials, ultrasonic welding will not work most of the time. Therefore, the ultrasonic welding process must be selected, it is not easy to change the parts material. Some engineers have reported to the author, why the ultrasonic welding of two plastic parts of ABS material, the welding quality is very good, but because of other design requirements, it is difficult to weld the ABS material of one plastic part into PBT? That's the reason.

2) Non-detachable.

Ultrasonic welds are non-removable connections and cannot be reworked. Once the two parts are assembled by ultrasonic welding, they cannot be reworked if quality problems are found later.

3) Limitations on the size and shape of parts.

Small - and medium-sized plastic parts are suitable for ultrasonic welding, usually less than 250mmx300 mm in size. Larger parts may be run in more than one welding process. And ultrasonic welding is generally suitable for the shape of a single plastic parts, for the shape of complex plastic parts, the welding quality may be low.

4) May cause damage to the plastic structure

Ultrasonic energy is very large, in the welding process may cause damage to the plastic parts themselves because of insufficient strength, but also may cause damage to other parts inside the product. Therefore, in the product design, as far as possible to increase the strength of plastic parts and the strength of other parts inside the product, or parts away from the welding area, as far as possible to arrange the strength of other parts after the ultrasonic welding process before assembly. Some electronic components on the electronic control board need special attention.

5) Technical requirements for debugging personnel

At present, the quality of ultrasonic welding is greatly dependent on the adjustment technology of ultrasonic welding machine and the degree of care of operators. Many products in the previous ultrasonic welding welding occurs not strong enough or quality problems such as excessive welding surface melting, engineer will think the quality of the ultrasonic welding can only achieve this step, but the vast majority of quality problems can be solved by welding parameters adjustment, but the need to rely on tuning machine technology and careful operator. The most effective way is to ask for the help of professionals from ultrasonic equipment suppliers.

6) Ultrasonic is harmful to people's hearing, so labor protection supplies should be prepared. Especially when welding the high pitch, some people will be particularly uncomfortable.