All plastics that can be laser-welded are thermoplastics. In theory, all thermoplastics can be welded with a laser blast. Plastic laser welding technology requires that the material to be welded in thermal effect zone has good absorption of light wave. Materials that are not in the thermal effect zone require good transmission of light waves, especially when two thin maggots are welded together. The purpose can be achieved by adding absorbent to the simulation of the general thermal effect zone.

Plastic parts made from these plastics, such as molded plastic products, plastic sheets, films, synthetic rubber, fibers and even textiles, can be used as welded objects. Because laser welding has a small thermal effect zone that traditional welding does not have, the above single material can also be welded.

The application of absorbent is a very important process in plastic laser welding. The essence of plastic laser welding is to melt the plastic to be welded in the thermal effect zone and then cool it naturally to complete the connection of plastic parts.

To melt plastic, the plastic part needs to absorb enough laser energy. Generally do not add absorbent, plastic absorption of light wave is not very good, absorption is very low, melting force is not ideal. Usually the ideal absorbent is carbon black, which can fully absorb the laser energy of infrared wavelength, thus greatly improving the heat-absorbing effect of plastic, so that the data in the thermal effect zone melt faster, the effect is good.

Carbon black absorbs visible light as well as infrared laser waves, which is why it looks black. Using carbon black as an absorbent will make the laser weld darker in color than the base material. Some dyes of other colors also absorb light waves. Bright plastic welds can be obtained by using this dye as absorbent. The idea is that the dye only absorbs infrared electromagnetic waves, not visible light, so the weld looks bright.

Unlike metal welding, the laser power required for plastic laser welding is not always better. The higher the welding power, the larger and deeper the heat affected zone (HAZ) on the plastic parts, which may lead to data overheating, deformation or even damage.

The laser power should be selected according to the melting depth. The speed of the plastic welder is relatively fast. Generally, the welding speed of 1mm thick welds can reach 20m/min. When welding plastic film with high-power CO2 laser, the speed can reach 750m/ min. Computer software plays an important role in laser welding system.

The software can digitally control the general process parameters, such as the trajectory and speed of the laser head, laser power, etc. So as to improve the processing speed and accuracy, improve the processing quality. According to the thickness, color, absorption rate of different data, coupled with the laser power, light wave transmittance and other parameters, the software simulation software can get the amount of absorbent required before welding and the increase method, as well as the energy loss of laser light wave in the upper layer during welding. The calculated results are very close to the measured results.

As the 2000w hand-held fiber laser welding machine has strong regularity and good guessability, it is feasible to choose the software accounting selection method and guess the results.