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All About Plastic Welding

Plastic welding is a crucial component in the manufacturing or repair of plastics that don't bond with adhesive materials. If your current project relies on polyethylene- or polypropylene-based products, plastic welding will be your best bet for working with and uniting these plastics.

Keep reading to learn more about what plastic welding is and what the process looks like.

What Is Plastic Welding?

Plastic welding is a technical process that involves bonding compatible thermoplastics together. This connection is formed at the molecular level and relies on pressing, heating, and cooling to achieve a finished product.

While all plastic welding processes rely on these three components, the processes can further be broken into different subgroups depending on how the end result is achieved.

What Are the Plastic Welding Processes?

The various welding processes depend on how the plastics are heated, how much pressure is used during the process, and what types of machines or equipment are used. Here are just a few of the most common types of plastic welding and what practical applications these processes have.

Hot Plate

Hot plate welding happens as plastic parts are pushed together against hot plates for about 1020 seconds. This process relies on a combination of convection, conduction, and radiation through the hot plates and into the thermoplastics and can be used for plastic pieces ranging from an inch up to five feet.

Hot plate welding can be useful in projects involved in connecting gas service pipelines following repairs and excavations or, on a smaller scale, for factory production of something like car battery casings.

Infrared and Laser

Infrared and laser welding are forms of non-contact welding similar to hot plate welding. There are two main infrared welding techniques — using an electrically heated plate (with a metal or ceramic coating) or using one standard hot plate and one in which the heater is replaced with infrared emitters.

Lasers are often used in conjunction with infrared welding. In this process, lasers carefully and precisely melt the thermoplastics.

Because infrared and laser welding is such a precise and controlled process, it can be used for projects involving sensitive electronics without harming the electronics; projects that require joining complex parts, shapes, or 3D components; and small-scale projects.


Spin plastic welding is a process where round thermoplastic parts are rotated in relation to each other causing friction which heats the plastics. This process has a weld time of 0.5 to 5 seconds and can be used for plastic parts ranging from 0.5 inches to 9 inches.

Today, spin welding has a number of applications such as manufacturing and repairing aerosol cylinders, floats, fuel filters, piping, and tanks.


Ultrasonic welding uses high-frequency electrical energy converted into mechanical motion to join thermoplastics. The mechanical motion created is used in conjunction with pressure to create the heat for a solid weld. Weld time is 0.1 to 2 seconds and used for 1/8-inch to 12-inch pieces.

This type of welding serves a wide range of industries, including aerospace, automotive, medical, and packaging, though it is limited to smaller welds.


Vibration welding uses orbital or linear motion to create friction, which then generates enough heat to weld a joint. The weld time for a vibration weld is one to five seconds and is used for parts ranging from two inches to five feet long.

Vibration welding can be used for small to large assemblies and part sizes ranging from automotive armrest manufacturing to laundry machine drums production.

Plastic welding has useful applications for a range of products, big or small, and across all industries. To learn more about plastic welding, contact MGM Plastics today. Our skilled welders can help you create products or repair and refurbish existing items, and we can weld thermoplastics including ABS, PFA, polyethylene, polypropylene, PVC, and PVFD.


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