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Plastic welding

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VivekCholleti1

This document discusses different types of plastic welding processes. It describes friction welding which uses rotational motion and heat to weld thermoplastics. Hot gas welding is also discussed, which uses a heated gas stream like air to melt and fuse plastic materials together. Implant welding embeds metal inserts between plastic parts and then heats the inserts inductively or through resistance to melt the plastic and form a joint around the inserts.

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PLASTIC WELDING P.SAI KRISHNA 17281A0328
Plastic welding
Plastic welding processes can be divide into two groups: - ▶ Processes involving mechanical movement – friction welding. ▶ Processes involving external heating – hot gas welding and implant welding.
Plastic welding
Plastic welding
Plastic welding
â–¶ The friction welding of thermoplastic (also called spin welding) is based on the same principle as that employed for welding metals. In this process one of the substrates is fixed, while the other is rotated with a controlled angular velocity. When the parts are pressed together, frictional heat causes the polymer to melt and a weld is created on cooling. Major welding parameters include rotational speed, friction pressure, forge pressure, weld time and burn off length. â–¶ The advantages of friction welding are high weld quality and the simplicity and reproducibility of the process. The drawback of this process is that, in its simplest form it is suitable only for applications in which at least one of the components is circular and requires no angular alignment.
Plastic welding
â–¶ This is similar to oxy-acetylene welding of metals. The only difference is that the open flame of oxy-acetylene welding is replaced by a stream of hot gas. Compressed air, nitrogen, hydrogen, oxygen or carbon dioxide is heated by an electric coil as it passes through a welding gun. â–¶ Hot gas welding is a fabrication process for thermoplastic materials. The process, invented in the mid 20th century, uses a stream of heated gas, usually air, to heat and melt both the thermoplastic substrate material and the thermoplastic welding rod. The substrate and the rod fuse to produce a weld. To ensure welding takes place, adequate temperature and pressure must be applied to the rod, along with the use of the correct welding speed and gun position. â–¶ Typical applications include chemical storage vessels, ventilation ducting and repair of plastic moldings such as car bumpers. Nitrogen is used for oxygen sensitive plastics such as polyethylene while oxygen results in higher weld strengths. Compressed air is popular since it gives satisfactory results for many purposes and is cheap.
IMPLANT WELDING
➢ In this process, metal inserts are placed between the parts to be joined and are then heated by means of induction or resistance heating. The resistance method requires that wires be placed along the joint to carry current to the implants; this is not required for induction welding. The thermoplastic material melts around the implants and flows to form a joint. Implant welding has been applied to complicated joints in large components such as vehicle bumpers, electrically driven vehicles and sailingdinghy hulls.
Plastic welding
Plastic welding
Plastic welding

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Plastic welding

  • 3. Plastic welding processes can be divide into two groups: - â–¶ Processes involving mechanical movement – friction welding. â–¶ Processes involving external heating – hot gas welding and implant welding.
  • 7. â–¶ The friction welding of thermoplastic (also called spin welding) is based on the same principle as that employed for welding metals. In this process one of the substrates is fixed, while the other is rotated with a controlled angular velocity. When the parts are pressed together, frictional heat causes the polymer to melt and a weld is created on cooling. Major welding parameters include rotational speed, friction pressure, forge pressure, weld time and burn off length. â–¶ The advantages of friction welding are high weld quality and the simplicity and reproducibility of the process. The drawback of this process is that, in its simplest form it is suitable only for applications in which at least one of the components is circular and requires no angular alignment.
  • 9. â–¶ This is similar to oxy-acetylene welding of metals. The only difference is that the open flame of oxy-acetylene welding is replaced by a stream of hot gas. Compressed air, nitrogen, hydrogen, oxygen or carbon dioxide is heated by an electric coil as it passes through a welding gun. â–¶ Hot gas welding is a fabrication process for thermoplastic materials. The process, invented in the mid 20th century, uses a stream of heated gas, usually air, to heat and melt both the thermoplastic substrate material and the thermoplastic welding rod. The substrate and the rod fuse to produce a weld. To ensure welding takes place, adequate temperature and pressure must be applied to the rod, along with the use of the correct welding speed and gun position. â–¶ Typical applications include chemical storage vessels, ventilation ducting and repair of plastic moldings such as car bumpers. Nitrogen is used for oxygen sensitive plastics such as polyethylene while oxygen results in higher weld strengths. Compressed air is popular since it gives satisfactory results for many purposes and is cheap.
  • 11. ➢ In this process, metal inserts are placed between the parts to be joined and are then heated by means of induction or resistance heating. The resistance method requires that wires be placed along the joint to carry current to the implants; this is not required for induction welding. The thermoplastic material melts around the implants and flows to form a joint. Implant welding has been applied to complicated joints in large components such as vehicle bumpers, electrically driven vehicles and sailingdinghy hulls.