Typical methods for joining plastic parts include screw connections, snap fasteners, press fittings, adhesive bonding, and welding. Welding is an effective method for permanently joining plastic parts. There are various plastic welding processes, including ultrasonic welding, vibration friction welding, laser welding, hot plate welding, and infrared welding.
Vibration friction welding machines are suitable for welding compatible thermoplastic materials where the weld seam is on a large flat surface. They can achieve high-strength, high-pressure-bearing, and high-sealing weld performance. It is a highly precise and repeatable continuous production process, similar to pressing two palms together and moving them back and forth to generate heat.
From a material perspective:
1. The molten material is not exposed to air, therefore there is no risk of oxidative degradation.
2. There are virtually no requirements regarding material transparency, wall thickness, and weld height, unlike laser welding or ultrasonic welding which are limited by these factors.
3. Heat is concentrated at the weld seam, and the heat-affected zone is small, thus greatly reducing the possibility of material degradation due to overheating.
4. Low-stiffness modulus thermoplastics, such as TPC, cannot be welded.
5. Materials with large differences in melting points cannot be welded.
Process Advantages:
1. Economical, fast production cycle.
2. Relatively simple equipment.
3. Suitable for large-scale production.
4. Can produce various products by changing molds.
5. Almost no smoke during welding.
6. Products are subject to vibration during welding; sensitive parts may be damaged.
7. Due to the high welding pressure and lateral force, it is not suitable for welding small-sized products.
Appearance and Shape Requirements:
1. There may be overflow around the weld after welding. If overflow is unacceptable, a baffle groove can be designed to prevent it from being visible.
2. Dust particles are generated during welding, affecting the cleanliness of the internal parts.
3. Warping of parts may affect the welding effect.
4. Ideal for parts with an almost flat weld area. For curved surface welding, the angle along the vibration direction should be less than 15°; the angle along the direction perpendicular to vibration should be less than 40°.
