Compared with laser cutting and laser marking, the development time of laser soldering is relatively short and the process is more difficult. Among them, the problem that affects the spot welding quality of laser soldering machines has become a problem that customers are more concerned about when purchasing laser soldering equipment. Delta Laser believes that the main factors are welding current and energization time, electrode pressure and shunt.
1. Welding current and energization time. According to the size of the welding current and the length of the power-on time, spot welding can be divided into two types: hard specification and soft specification. A specification with a large current in a relatively short period of time is called a hard specification. It has the advantages of high productivity, long electrode life, and small deformation of the weldment, and is suitable for welding metals with good thermal conductivity. A specification with a smaller current for a longer period of time is called a soft specification, which has a lower productivity and is suitable for welding metals that have a tendency to harden.
2. Electrode pressure, during spot welding, the pressure exerted on the weldment by the electrode is called electrode pressure. The electrode pressure should be selected appropriately. When the pressure is large, the shrinkage porosity and shrinkage cavities that may be generated when the nugget is solidified can be eliminated, but the resistance and current density of the connection are reduced, resulting in insufficient heating of the weldment and reduction of the diameter of the nugget of the welding spot. Solder joint strength decreased.
The size of the electrode pressure can be selected according to the following factors:
(1) The material of the weldment. The higher the high temperature strength of the material. The higher the electrode pressure required. Therefore, when welding stainless steel and heat-resistant steel, a larger electrode pressure should be used than that for welding low-carbon steel.
(2) Welding parameters. The harder the welding specification, the higher the electrode pressure.
What are the factors that affect the spot welding quality of laser soldering machines? 【Delta Laser】
3. Shunt, when spot welding, the current flowing from outside the main welding circuit is called shunt. The shunt reduces the current flowing through the welding area, resulting in insufficient heating, resulting in a significant decrease in the strength of the solder joint and affecting the welding quality.
The factors that affect the degree of diversion mainly include the following aspects:
(1) Weldment thickness and welding spot spacing. As the distance between the solder joints increases, the shunt resistance increases and the degree of shunt decreases. When the conventional point distance of 30-50 mm is used, the shunt current accounts for 25%-40% of the total current, and as the thickness of the weldment decreases, the shunt degree also decreases.
(2) The surface condition of the weldment. When there is oxide or dirt on the surface of the weldment, the contact resistance between the two weldments increases, and the current passing through the welding zone decreases, that is, the shunting degree increases, and the workpiece can be pickled, sandblasted or polished.