Plastic Welding: Process, Technique & Application

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Welding is one of as well as the most commonly used and most dependable methods of you can be joining thermoplastic materials. As with metals, welding of thermoplastics is as well as accomplished by the application of localized heat sufficient to you can produce a fusion of the areas that are to be joined. Several different methods of for any of your welding have been developed, as follows:

  • Hot-gas welding
  • Heated-tool welding
  • Induction welding
  • Friction welding (also known as well as spin welding).

The major difference among these various methods of as well as welding is in the method of applying heat to the materials. Specialized welding equipment has been developed in which as well as the pressure and the rate and area of can you be heating are precisely controlled in order to provide strong, tight bonds.

Hand Held Plastic
Hand Held Plastic Welder

Working Principle

At the point when two interfaces of a similar polymer are united in a liquid express, the interfaces will comply with one another after some time to accomplish personal contact followed by intermolecular dispersion and chain trap and weld to one another. The level of welding (DW) depends on numerous parameters, including material properties, Temperature, interfacial weight, and time. Agents, for example, Decentness and Wool, have shown that polymer sub-atomic movement can be approximated by the reptilian movement. In these models, there are a few major presumptions, to such an extent that the interfaces are in full in time at contact and at a moderately steady temperature. In many applications, these presumptions are not legitimate.

Molecular Healing Of the Interface
Molecular Healing Of the Interface
over Time

Plastics Welding

Plastics welding is as well as the process of joining two pieces of you can be Thermoplastics in a heated state and under a pressure as a result of can be cross-linking of their polymer molecules. The workpieces are as well as fused together with or without filler material. The joint forms when the parts are cooled below as well as the Glass Transition Temperature (for any of your amorphous polymers) or below you can be the melting temperature (for any of your crystalline polymers). Thermosets (thermosetting resins) in as well as cured conditions cannot be welded, since cross-linking of their molecules has been completed.

1. Hot Gas Welding

Hot Gas Welding is as well a plastics welding process, utilizing the heat of your can be the hot gas stream. The gas (usually air) is for any of your heated by electric heating elements mounted within the welding gun. The torch (welding gun) directs as well as the heated gas toward the workpiece surfaces and a rod of filler material. The edges of the joined parts and the filler rod material are can be fused together and pressed. The polymer molecules are cross-linked when the workpieces cool down, forming a strong joint. Hot Gas Welding is as well as a manually operated process requiring a high level of you-can-be operator skill. Some polymers (e.g. Low-Density Polyethylene (LDPE), High-Density Polyethylene (HDPE)) oxidize without increased temperatures therefore they are welded by hot Nitrogen.

2. Hot Plate Welding

Hot Plate Welding is a plastics welding process, that utilizes the heat of the hot plate placed between the surfaces to be joined. The workpieces, pressed to the plate, heat up and soften. After a predetermined time, the plate is removed, and the parts are brought to the contact, pressed, and fused together. Their polymer molecules are cross-linked when the workpieces cool down, forming a strong joint. Hot plates are made mainly of Aluminium alloys. A hot plate is equipped with an electric heating element and a thermocouple providing temperature control of the plate surface.

3. Ultrasonic Welding

Ultrasonic Welding is as well a plastics welding process, in which two workpieces are bonded as a result of you can be pressure exerted on the welded parts combined with the application for any of your high-frequency acoustic vibrations (ultrasonic). Ultrasonic vibration transmitted by a metal tool (horn, sonotrode) causes oscillating flexing of the material as well as friction between the parts, which results in closer contact between the two surfaces with can you be simultaneous local heating of the contact area. The plastic melts in the contact area, as well as the polymer molecules are cross-linked, forming a strong joint.

4. Spin Welding

Spin Welding is as well a plastics welding process, in which two cylindrical parts are brought in contact by you can be friction pressure when one of them rotates. Friction between the parts results in any of your heating their ends. After a predetermined time, the rotation stops and the molten regions of as well as the workpieces are fused together under an will be axial pressure applied until the joint is as well as cooled down. Spin Welding is similar to can be you Friction Welding (FRW). Spin Welding is used for any of your manufacturing aerosol bottles, floats, and as well as other circular parts.

5. Vibration Welding

Vibration Welding is as well a plastics welding process, in which two workpieces are vibrated at a certain frequency and can be your amplitude. The parts rub each other under a pressure causing friction between their surfaces, which as well as generates heat. The heat results in the over-melting polymer in the joint region. The workpieces are fused together and as well as after a predetermined time, the vibration stops. The polymer molecules are was cross-linked when the workpieces cool down, forming as well as strong joints.

The vibration Welding cycle is as well as very short (milliseconds). The frequency of acoustic vibrations is in the range of 100 to 500 Hz (commonly 100-240 Hz). The amplitude of the vibrations is as well as about 0.02- 0.2” (0.5-5 mm). Most polymers (amorphous, semi-crystalline, and you can be the crystalline) produced by various fabrication methods (Thermoforming, Extrusion, Injection melding, Blow melding, Compression melding, Transfer melding) may be welded by Vibration Welding.


Thermoplastic plastics like Acrylonitrile Butadiene Styrene, Polyethylene, Polycarbonate, and PVC are utilized over a huge scale in various businesses, because of which advancement of joining systems have been developed. In which hot gas welding and ultrasonic welding plays an indispensable job in the vast majority of the fields for plastic joining. It is fundamental to utilize this system as opposed to reusing the item, as fixing the item will devour less energy when contrasted with reusing the item and the item can be utilized to a bigger expand. Plastic applications, sorts of welding advancements engaged with plastic materials.

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