What are the different methods of plastic welding?

Plastic welding has permeated various parts processing within the industrial sector, and

 the production of everyday consumer goods relies heavily on plastic welding technology. 

Plastic welding is one of the primary methods for secondary processing of thermoplastic 

plastics. It takes advantage of the fact that thermoplastic plastics can be melted, using heat

 to simultaneously melt the surfaces of two plastic components. Under external force, these

 components are joined together, forming a weld. Depending on the heating method used,

 plastic welding can be categorized into methods such as hot plate welding, induction welding, 

friction welding, ultrasonic welding, high-frequency welding, and hot air welding.

Plastic Welding Manufacturers: Hot Plate Welding

Hot plate welding involves using a heating tool, such as a hot plate, heated strip, 

or heated soldering iron, to directly heat the surfaces of two plastic parts being

 joined. The heating continues until there is a sufficient molten layer on the surfaces.

 The heating tool is then removed, and the two surfaces are pressed together until 

the molten portion cools and solidifies. This process of connecting two plastic parts 

is known as hot plate welding. It is suitable for welding products made of materials 

such as acrylic, rigid PVC, flexible PVC, high-density polyethylene, polytetrafluoroethylene,

 polycarbonate, polypropylene, and polyethylene. Currently, this process is commonly 

used for PP-R fittings and other connections.

Plastic Welding Manufacturers: High-Frequency Induction Welding

In high-frequency induction welding, metal inserts are placed on the surface of the 

plastic weld seam and temporarily bonded under appropriate pressure. The assembly

 is then placed in an alternating magnetic field, which induces heat in the metal insert, 

causing the plastic to melt and bond. After cooling, the welded product is obtained. 

This welding method is referred to as dielectric welding and is applicable to almost all

 thermoplastic plastic welding.

Plastic Welding Manufacturers: Ultrasonic Welding

Ultrasonic welding is also a form of heat welding. Heat is generated by using ultrasonic

 vibrations to mechanically agitate the plastic. When ultrasonic vibrations are directed 

onto the plastic surfaces to be welded, the plastic particles are stimulated by the ultrasonic

 waves and vibrate rapidly, generating mechanical agitation. Through this conversion to 

heat, the temperature of the welded plastic surface increases and melts, while the 

temperature of the unwelded surface remains unaffected. Ultrasonic energy is introduced

 into the welding plastic through the welding joint. When the ultrasonic welding stops, the

 plastic immediately cools and solidifies. Depending on the structure of the ultrasonic 

welding machine, various thermoplastic plastics can be welded.

Plastic Welding Manufacturers: High-Frequency Welding

Two overlapping plastics are placed between two electrodes, and the electrodes are subjected

 to high-frequency current. Under the influence of the electromagnetic field, the free charges 

in the plastic repeatedly and naturally move (polarize) at the same frequency (but slightly lag

 behind), causing the polarized molecules to vibrate frequently and generate friction until 

electric fusion occurs. It is suitable for plastics composed of polar molecules, such as films or 

sheets made of PVC and polyamide.

Plastic Welding Manufacturers: Friction Welding

The frictional heat generated between thermoplastic plastics can melt the friction surface, 

which then solidifies through cooling under pressure. This is known as friction welding. This 

method is suitable for cylindrical products.

Plastic Welding Manufacturers: Hot Air Welding

Hot air welding is easy to use and operationally straightforward, particularly suitable for welding

 plastic sheets. The process involves heating compressed air (or inert gas) to the temperature

 required for welding the plastic using a welding torch heater. Then, the welding rod and filler

 material are heated to a molten state using preheated gas, and the weld seam is secured together

 under slight pressure.

Plastic Welding Manufacturers: Laser Plastic Welding

Laser welding seems to have developed into a welding method particularly suitable for specific 

applications, offering cost and performance advantages compared to other methods such as

 ultrasonic welding, vibration welding, and hot plate welding.

A major advantage of laser welding is its ability to heat plastic components through non-contact 

methods, allowing for the plasticization of complex three-dimensional welding surfaces. As a result,

 infrared welding techniques are especially suited for complex curved parts and large structural 

plastic components.

With the increasing demand for lightweight tools and the rapid development of the plastics industry, 

plastic applications in daily life will become more widespread, and various plastic welding methods 

will continue to advance. The level of plastic welding technology seems to have become a benchmark

 for measuring automotive production technology and new material development. It is certain that 

various methods of welding plastics will play an even greater role.