First round: Product aesthetics
Laser welding uses a high-energy laser to melt the weld metal to create a joint. In the solar heat absorbing plate welding, welding is performed in the form of a solder joint with a spacing of 3-5 mm. Laser welding does not require pressurization on the workpiece, the overall deformation is small, and the surface damage to the heat absorbing layer is small. Ultrasonic metal welding causes wave deformation on the surface of the sheet due to pressure. Although surface deformation can be avoided by surface embossing, a weld mark of about 3 mm is formed on the surface of the solar heat absorption. Therefore, the appearance of products using laser welding is better than that of ultrasonic metal welding. This round of competition, laser welding is better than ultrasonic metal welding.
Second round: Persistence
The welding strength of laser welding is poor. When the hot and cold alternates frequently or is subjected to external force, the solder joint is easy to break. Ultrasonic metal welding is to superimpose two objects to be welded by vertical pressure, combined with ultrasonic vibration and pressure to form a solid connection. The bonding time is short and the joint part does not produce casting structure defects, so the welding position is uniform and stable, and the ultrasonic metal. There was no fracture after the 90 degree vertical bending test. This round of competition, ultrasonic metal welding is better than laser welding.
Third round: Thermal conductivity
Laser welding can change the physical structure of the object being welded, thus affecting its electrical or thermal conductivity. Moreover, the laser welding results in a small heat conduction area between the metal piece of the solar collector and the copper tube, which affects the heat conduction efficiency. Ultrasonic metal welding does not have this problem. Ultrasonic welding minimizes the temperature effects of the material and does not alter the metal structure. Therefore, the electrical conductivity or thermal conductivity after welding is excellent, and the electrical resistivity is extremely low or nearly zero. Ultrasonic metal welding has become the best choice for welding conductive and thermal conductive materials. This performance can obviously produce laser welding on flat solar collectors. The advantage that cannot be achieved. According to the test, the ultrasonic metal welding product is about 3% higher than the laser welding conduction efficiency (that is, the water temperature is about 3% under the same working condition). This round of competition, ultrasonic metal welding is significantly better than laser welding.
Fourth round: Energy consumption
As a representative product of low-carbon energy-saving and environmental protection, solar water heaters are widely recognized by the society and consumers, and energy consumption indicators in the production process are also receiving much attention. Welding of solar collectors is one of them. From the comparative analysis of the welding principle, it can be known that ultrasonic metal welding can minimize the temperature effect of the material (the temperature of the weld zone does not exceed 50% of the absolute melting temperature of the weld metal), so that the metal structure does not change, so it does not It will anneal metal workpieces without cooling water. In terms of energy consumption, ultrasonic welding can be performed between the same metal and different kinds of metals, which is much less energy-consuming than laser welding. This round of competition, ultrasonic metal welding is better than laser welding.
Fifth round: Cost
1. Cost of equipment: internationally, the price of ultrasonic welding machine and laser welding machine is equivalent. The procurement cost of single equipment of ultrasonic metal welding machine is lower than that of laser welding machine. The procurement ratio of the two is usually 300,000: 10,000. (Now the price of domestic laser welding machines is also rapidly declining, about to about 700,000) The laser welding machine generally has two laser welding heads, and the ultrasonic machine generally has one welding head. For the same production capacity, two ultrasonic welding machines are compared with one laser welding machine.
2.Cost of use: Firstly, laser welding is suitable for thick materials, such as welding aluminum. The thickness of aluminum plate is generally chosen to be 0.4mm, while ultrasonic welding is suitable for thin products, such as aluminum plate, generally 0.2-0.3mm. In terms of welding materials, ultrasonic is superior. Secondly, the cost of consumables, the consumables for laser welding are xenon lamps and filter cartridges, and the ultrasonic consumables are welding heads. In general, laser welding consumables are cheaper than ultrasonic.