Long lap welding

1.The squeeze roller moves axially

Due to the unstable positioning of the squeeze roller and the squeeze roller shaft, as well as the openness of other zero parts during assembly, the squeeze roller will move axially and swing radially. The pass of the squeeze roller will not match and cause lap welding.

2.Bearing damage

After the bearing is damaged, the normal position of the squeeze roller will be destroyed. Take the two-roller type squeeze roller device as an example. Generally, two sets of bearings are installed in the squeeze roller. When one of the squeeze rollers is damaged, the squeeze roller loses control, and the weld seam will rise higher and cause lap welding. In the production operation, we can observe the swing of the squeeze roller. When the upper bearing is damaged, the swing of the roller is larger, and when the lower bearing is damaged, the swing of the roller is smaller, and it also has a certain relationship with the degree of bearing damage.
After the bearing of the guide roller is damaged, not only can it not well control the direction of the weld of the tube blank, but the guide ring may also cause pressure loss on the edge of the tube due to the damage of the bearing, which will change the height of the weld, which is slightly inappropriate. There will be lap welding accidents.

3.The Squeeze Roller is Bent

Still taking the two-roller squeeze roller device as an example, there are two reasons for the bending of the squeeze roller shaft: one is the external bending due to insufficient top wire pressure for a long time; the other is the internal bending when the top top wire pressure is too high. During inspection, release the top tightening device and place the vertical surface of the steel ruler on the end surface of the roller to check the inclination angle between the end surface of the other roller and the steel ruler. When the shaft is bent outside, the scratches are caused by the rollers of the bent shaft; when the shaft is bent inside, the scratches are caused by the rollers that do not bend the shaft.