The difference between spot welding machine and laser welding machine
In welding, it is common to treat two materials to make it a whole. For automotive steel welding, for example, the welding process is actually heating the steel plate to liquefy the material and recrystallizing the entire process during cooling. During the entire process, the heating and cooling time is very important because of heating and cooling. Different time, the crystallization of steel can be divided into many types. In general, the faster the heating and cooling speed, the less likely it is to change the original characteristics of the steel plate. The less the change in the nature of the steel plate caused by welding, the more consistent the design of the car's strength is. The more secure the security.
Spot welding machine is to produce instant high-temperature and high-pressure environment through two electrodes to generate instantaneous high-temperature and high-pressure environment, to melt the steel plate, and crystallize during cooling. The two steel plates are connected together. The advantage of this welding method is that multiple layers of steel plate can be welded. At the same time, the combination of multi-layer steel plates has the disadvantage that the heat and pressure generated during the welding process cannot be well controlled, so that the cooling time of the plate after welding is too long, and the thermal stress changes easily, if it is to prevent thermal stress changes. Reduce the welding pressure and heat, it is easy to produce the phenomenon of welding impervious, recently seen a variety of models dismantling the door posts, there is a Corolla car is very uneven spot welding, and there is no penetration of welding and excessive welding phenomenon, It is a special case that does not control the pressure and current during the welding process.
The principle of Laser welding machine
is to produce high-temperature melting steel plate instantly. Laser welding technology can effectively control the welding area and control the intensity and welding speed of laser. Therefore, during laser welding, the material is instantaneously heated and cooled instantaneously. The crystallization speed is fast, the produced crystal grains are small, there is almost no thermal stress area, and it is effective to ensure that the original properties of the material are not greatly changed and it is easier to reach the design strength. Another major advantage of laser welding applications in automotive manufacturing is the absence of welding flanges, the so-called weld bead, the raised strip on the body, or the point-by-point welding, which is not visible on the laser welded body. To the
With the spot welding of the body, the welding point is obvious, and the welding width is much larger than the depth; in the laser welding body, the welding bead is hardly visible, and the welding width and depth are basically the same, in other words, the spot welding body looks at the welding. The point is very big, in fact, the welding depth is very small, but the width of the laser welding bead is wide, the depth is basically the same, the spot welding is the point of contact, is flat, and the laser welding is the surface contact, can be seen as Three-dimensional.
Go back and talk about the changes in the steel plate during welding. During the spot welding process, due to the slow cooling rate, the steel plate is welded and melted to produce metal crystals, which affects the bonding between the two steel plates. During the laser welding process, the metal material heats faster and the cooling rate is faster, and the metal material grains are very small, effectively maintaining the original properties. Therefore, it can be said that the spot welding belongs to the combination of crystals, which is a wedge between crystals and crystals of two steel plates. Laser welding produces few crystals and belongs to the molecular level. According to professional data, under the same conditions, laser welding is 30% stronger than spot welding.
Everyone knows the principle of thermal expansion and contraction, and the same is true for metal materials. After welding, the heat of welding remains high, causing the metal to expand. After cooling, it will always produce a certain amount of deformation, which affects the accuracy of the parts. In the case of simple door hinges, using other welding methods will always result in a certain change in the shape and position of the hinge, which will affect the sealing of the door. The laser beam can be adjusted to a very small laser beam with a concentrated heating area. Residual residual heat does not easily cause deformation of the part after welding, so the door hinges are generally laser welded.
For multi-layer materials welding, laser welding still has weaknesses, but the development of laser welding technology has been gradually overcome these difficulties, especially the laser welding machine industry in Shenzhen, Guangdong, the rapid development, I believe the near future, laser welding will be used as a car The major welding processes that have been manufactured have emerged, and the safety of automobiles has also been greatly improved.