Frequently Asked Questions
There are many techniques (over 20) for joining plastics including:
- Adhesive bonding
- Solvent welding
- Mechanical/snap fits
- Hot plate welding
- Hot bar welding
- Impulse welding
- Hot gas welding
- Extrusion welding
- "Flashfree" or BCF
- Vibration welding
- Spin welding
- Ultrasonic welding
- Friction stir welding
- Resistive implant welding
- Induction welding
- Dielectric welding
- Laser welding
- Infrared welding
- Microwave welding
The most commonly used methods for nylon are spin, vibration, dielectric and ultrasonic welding. Laser welding and non-contact infrared have also successfully been used. The choice of process is affected by the form of the material- moulded component or film
The key issues specific to the welding of nylon are:
- Check which type of nylon it is as there are several types.
- Nylon is hygroscopic, therefore injection mouldings require 'drying' in an oven at 60°C overnight prior to welding.
- Nylon is semicrystalline, with a sharp melting point. To ensure successful ultrasonic welding, mouldings need to be carefully designed with the appropriate joint configuration.
- Glass-filled nylon produces a fine swarf during frictional welding processes such as spin or vibration welding. Flashtraps need to be designed into the mouldings.
- To dielectric weld nylon film, it may be necessary to preheat the welding tool to about 45-50°C. This helps to raise the temperature of the nylon above its T g (glass transition temperature), giving it the capacity to flow and hence to weld.
See further information about plastics welding and testing or please contact us.