What are the differences between ultrasonic metal welding machines and ultrasonic plastic welding machines?
Ultrasonic metal welding is the use of tens of thousands of high-frequency vibration wave per second to the surface of the two metal workpieces to be welded, and then apply a certain pressure, so that the metal surfaces rub against each other to form the fusion between the molecular layer, achieving purpose of welding.
Ultrasonic welding equipment is a high-tech technique for welding plastic products. Various plastic parts can be processed by ultrasonic welding. When welding plastic products, neither add any adhesive, filler or solvent, nor consume a lot of heat sources.
The differences between ultrasonic metal welding machines and ultrasonic plastic welding machines is as following:
1. First of all, the way of working is different.
Generally, the vibration direction of the welding head in the ultrasonic plastic welding is perpendicular to the welding position, and the vibration direction of the welding head in the ultrasonic metal welding is parallel to the welding position. In some special cases, plastic welding can also be used in parallel directions, such as thinner plastic parts.
2. Secondly, due to the application of ultrasonic in welding metals, higher requirements are placed on ultrasonic welding technology. Compared with ordinary plastic welding, the requirements for power capacity, power density, stability, and automatic control are not the same level.
Currently, domestic ultrasonic plastic welding generators basically use self-excited circuits, typically represented by: 8400, 8700 full-bridge circuits and Taiwan's machine commonly used half-bridge circuit, a notable feature is a tuning inductance. If the existing mature technology for plastic welding is directly transferred to metal welding, its technical innateness will lead to unstable use of the product; its only advantage is that the price is cheap, but for the high requirements of the metal welding itself, This advantage is very pale.
1) High power , stable ultrasonic generator:
The first requirement for a stable ultrasonic generator is: frequency automatic tracking. Frequency automatic tracking can ensure that the transducer system can work in resonance, that is, the welding head amplitude is maximized. The use of frequency automatic tracking technology, the replacement of molds and work without the need for FM, is the basic requirements for metal welding. A device with manually adjustable frequency adjustable inductance can basically meet the requirements.
Stable ultrasonic generator also requires: constant amplitude function and amplitude stepless adjustment. Constant amplitude function, which can ensure the consistency of welding, is the key to stable production; stepless adjustment of the amplitude is the basic to ensure the use of equipment, such as the ability to weld copper and weld aluminum materials on the same equipment through parameter adjustment.
High power capacity: Compared with plastic welding, metal welding requires high energy density and must have relatively high power capacity. For example, a 20khz machine requires basically more than 3000w of power capacity.
2) High-quality welding heads: Metal welding, as an industrial application, inevitably requires a long-life welding head.
3) High-quality transducers: For example, a 20khz transducer must be able to withstand more than 3kw of load for a long time. Many companies' transducers use ordinary plastic welding transducers and are difficult to distinguish in appearance. This is irresponsible.
4) High-quality control system: It has three basic control modes: welding energy, time, and altitude. A variety of quality control software meets different requirements.