In the automobile industry, welding is a key link in the manufacture of automobile parts and body, which plays a special role in connecting the preceding with the following. At the same time, many types of automobile products, complex forming structure, specialized and standardized production of parts and components, as well as the comprehensive requirements of automobile manufacturing in terms of quality, efficiency and cost, all determine that automobile welding is a multidisciplinary and cross field Production process with strong technical integration:
1. High requirements for dimensional accuracy of weldment: in order to ensure the assembly accuracy and dimensional stability of the product, it is required to reduce the number of thin plates before welding as much as possible
Accuracy deviation and thermal stress and deformation after welding;
2. High performance requirements for welded joints: not only static and dynamic mechanical performance indexes, but also stringent low cycle fatigue performance requirements;
3. Requirements for high quality and good consistency of batch welding production;
4. Requirements for high beat and high efficiency in welding production process;
5. For the quality control and guarantee of "zero defect", the requirements of automatic welding process monitoring and information management are put forward.
Aiming at the development goal of "lighter, safer, better performance and lower cost" of automobile products, the current automobile welding technology is rapidly extending and expanding on the basis of traditional material connection concepts and methods, and developing towards the direction of advanced "precision welding manufacturing", among which the main welding methods are resistance welding, gas shielded welding, plasma welding and laser welding technology Technology (mainly used for body welding, welding and parts welding), plastic welding technology, etc
As Lingke ultrasonic focuses on the research of plastic welding technology such as ultrasonic welding, this paper only gives a detailed description of plastic welding technology:
Plastic welding technology: ultrasonic plastic welding is to transmit high-frequency mechanical vibration to the interface part through the workpiece, so as to accelerate the movement of molecules. Molecular friction is converted into heat to melt the plastic at the interface, so that the two weldments are truly integrated in the way of molecular connection. Because this molecular movement is completed in an instant, most of the ultrasonic plastic welding can be completed in 0.25-0.5s. Ultrasonic plastic welding is applicable to plastic parts with small welding area, regular structure and thermoplastic, such as window motor, built-in audio, foot pad, door plate, clutch fork, spare wheel box, bumper, filter, front baffle, etc.
Hot melt welding of hot plate: a thermoplastic welding process equipment that uses surface heat conduction to melt the surface of the plastic workpiece to be welded. It is not limited by the material and size of parts, and has good sealing performance. It is suitable for welding plastic parts which are difficult to melt by ultrasonic wave and large-size special-shaped parts, such as air bag, instrument panel, sun visor, vehicle mounted water dispenser, tail lamp, expansion water tank, brake oil cup, etc.
Rotary friction welding: the mechanical energy is converted into heat energy through the relatively high-speed rotary friction of the workpiece, so that the contact surface of the welded workpiece is heated up by friction, and then pressurized after melting, so as to weld together. This process is not limited by the size and material of the workpiece, and the welding strength is higher than other plastic welding processes, almost close to the strength of the plastic body. It is suitable for welding of rotary parts with large wall thickness and high connection strength, such as intake manifold, etc.
Vibration friction plastic welding technology: make the workpieces friction with each other under pressure, and the energy is transmitted along the welding position, and make the plastic melt because of friction heat in the specially designed position. After the melting period, it is cooled and solidified under continuous pressure. The interface strength after solidification is equivalent to the strength of the body plastic. It is suitable for the workpiece with large welding area and complex structure, and there is no special requirement for plastic type.
Lingke ultrasonic linggao ultrasonic welding machine