What are the common problems of plastic laser welding machines?

1. What is the principle of plastic laser transmission welding?

During laser transmission welding, the laser beam penetrates the upper transmission component and absorbs the laser component on the lower layer. The laser energy is absorbed by the dye or additive particles in the absorbing component and converted into heat. The surface of the absorbing component melts, and the heat is transferred to the upper transmission component according to heat conduction. Before welding begins, the two parts are in contact with each other under the action of external pressure. During the welding process, the parts are locally heated, and the thermal expansion of the material provides additional internal welding pressure. Under the combination of internal and external welding pressure, the two parts are firmly welded together. The relative movement of the laser beam and the welding parts forms the weld.

2. What are the problems with low laser penetration?

A series of process problems such as shrinkage marks, burns, and poor welding will occur. Black nylon or black nylon. PBT materialBe careful, its production and injection molding process can easily lead to unstable laser penetration of the workpiece after injection molding. Laser penetration detection instruments can be used for detection.

3. The upper transmission part is black, can it be welded?

Yes, it can be welded. Black plastics that are colored with special dyes or have laser absorbers added may also have sufficient laser transmittance. The material supplier must be consulted and tested.

Fourth, what is the typical weld design?

For the welding of plastic shells of electronic components such as EPB electronic parking brake, thermal management expansion valve, etc., the following weld design can be used. The weld width is 1.2mm, the weld collapse depth is 0.4mm, and the inner and outer ribs can prevent overflow and extrusion.

5. How to design the thickness of the upper transmission component?

1. General principle, amorphous plastics such as PC, PMMA and ABS, etc., are transparent without adding masterbatch, and their thickness is not specified. Welding semi-crystalline plastics, colorless masterbatch is milky white or creamy yellow, and the thickness is generally not more than 2mm. On the basis of ensuring the mechanical properties of the parts, the thickness should be as small as possible.

2. PBT material is selected, and the thickness is less than 1.5mm.

3. Nylon material is selected, and the thickness is less than 2mm.

4. POM material is selected, and the thickness is less than 3mm.

5. What is the quality monitoring in the laser welding process?

Use a thermometer to detect the temperature of the welding molten pool in real time. Pay attention to the temperature comparison value detected by the thermometer, not the actual value. Using a displacement sensor to monitor the welding collapse depth is a common quality monitoring method in the automotive parts industry. Use a force sensor to monitor the welding pressure.