Thermoplastic components can be welded in various different ways. Some manufacturers use hot plate, or ultrasonic welding, or even infrared welding. There are in fact more than a dozen commercially used welding techniques. The one you choose for your project will largely depend on your budget, production requirements and the nature of your components.
Many businesses find vibration welding – a method that uses linear vibrations to weld two plastic joints – to be an efficient alternative to other available methods. Opting for vibration welding gives you great flexibility to work with a range of component sizes. The process itself uses less energy than other welding techniques, and equipment involves less capital outlay. It is therefore surprising that vibration welding isn’t more popular with design engineers than it actually is.
If you are considering which welding method is suitable for your project, we recommend taking a look at vibration welding. Here is an overview of how the vibration welding process works:
Vibration Welding Machines
Vibration welding machines are actually quite simple pieces of kit, very suited for use on production lines. They are essentially vertical presses that vibrate two joints together under a defined pressure to generate friction. This friction melts the bonds between the two plastic edges which, when cooled, forms a reliably strong bond. Due to the simplicity of the process and no need for contacting hotplates, vibration welding is a maintenance free process making it ideal for large scale production. Full reliability in the welded product can be guaranteed by the high monitoring capabilities attainable from the Cemas range of welders.
Vibration Welding Steps
There are four main steps to the vibration welding process:
1) Friction Phase
The two components are bought together by the lifting platform and vibrator assembly, and then vibrated horizontally against each other. This produces heat at the point of contact.
2) Transitional Phase
The plastic where the two joints meet begins to melt, generating further heat. The melted layer becomes thicker and increases in viscosity. When viscosity reaches a critical stage, friction between the joints is reduced, resulting in a reduction of heat. The pressure of the system then causes an exchange of melted material between the two joints, creating a seamless bond.
3) Joining Phase
Once a join is affected, the vibrator assembly is switched off, preparing the joint for the final, cooling phase. This happens when the melt rate becomes equal to the outward flow of melted material, thus creating a strong and durable bond.
4) Cooling Phase
For a permanent weld, the two joints have to fuse at a molecular level, so the cooling process takes place under consistent pressure until it is completely solid.
By controlling the force, amplitude and penetration of the welding process, vibration welding gives you remarkable versatility in terms of the components and materials you can work with. It can be used to bond almost any thermoplastic, including dissimilar materials. It can also be applied successfully to components ranging from the very small to the quite large, making vibration welding suitable to a diverse number of projects.
Our FREE Guide to Vibration Welding
The methods, technologies and benefits of vibration welding are explored in more depth in our new eBook The Ultimate Guide to Vibration Welding. In this guide you will discover how vibration welding offers a cost-effective alternative to infrared and ultrasonic welding techniques. You can claim your copy by clicking here. To find out more about our CEMAS range of vibration welding machines, or simply to chat with one of our experts, please give us a call today on 01582 436000.