Laser processing technology and its application

Laser machining is a non-contact way, the tool and the workpiece surface do not produce friction resistance, do not directly impact the workpiece, and the workpiece is hardly deformed. Moreover, laser processing has little influence on non-laser irradiated parts, so laser processing is a high-speed, efficient and high-precision processing method. Laser processing technology is a combination of light and electromechanical technology, and the moving speed, power density and direction of laser beam can be adjusted, which is convenient to cooperate with CNC system to process complex workpieces and make it suitable for different levels and ranges.

one

Laser die cutting technology

Laser die-cutting technology is a cutting method that focuses the laser beam according to the workpiece pattern designed in the software and directly completes the die-cutting or indentation effect on the surface of the material. Laser die-cutting technology has the characteristics of high cutting precision, low roughness of die-cutting products, short die-cutting processing time and high production efficiency. Because there is no need to change the die-cutting blade, it can also realize the rapid conversion between different formats of workpieces, saving the adjustment time of traditional die-cutting blades, and is especially suitable for processing thin and irregular workpieces.

A typical laser die-cutting system should include laser, scanning system, control system, cooling system, inert gas protection room, waste removal system and feedback system. Laser plays the role of "die-cutting machine" in die-cutting processing, and has the greatest influence on the final processing effect among all parts of the die-cutting machine. At present, there are mainly YAG laser, CO2 laser and semiconductor laser used in laser processing on the market. The most commonly used is CO2 laser, whose output wavelength can be well absorbed by nonmetals and can generate continuous laser or discontinuous laser pulses.

two

laser carving technique

The laser engraving machine mainly consists of a laser (providing a laser beam, including a condenser cavity and a reflector), a focusing system (concentrating the laser energy with high power density on a small area to achieve the best engraving efficiency), a light guiding system (changing the irradiation direction of the laser), a workbench (for transporting or moving the workpiece to be engraved), a control panel (adjusting and controlling the power supply and the laser) and a water cooling system (adjusting and controlling the temperature in the laser). Because it mainly processes nonmetallic materials, CO2 laser is often used for laser engraving and die cutting. In order to realize high-speed lattice engraving and moderate engraving, laser engraving mostly adopts vibrating mirror light guiding system. three

Laser welding technology

Laser welding technology is mainly used to weld metal and plastic products. In the past, resistance welding technology was mostly used for metal welding, but there were some problems in resistance welding, such as large power consumption, large heat affected zone, unsightly interface and limited thickness of weldable materials, so laser welding technology was more and more widely used. The mechanism of laser welding metal is that the metal surface is irradiated by laser, and the part to be welded is instantly melted or even gasified in a very short time through the coupling between laser and metal, and then cooled, solidified and crystallized to form a weld. Laser welding can be divided into two types: thermal conduction welding and deep penetration welding. In the former, the laser power density is low, the radiation energy only acts on the metal surface, and the lower layer material is heated and melted by heat conduction. Deep penetration welding will produce pinhole effect, that is, when the input laser energy is very large, which is far greater than the rate of conduction and heat dissipation, the irradiated area will vaporize to form pinhole in a very short time, and the pressure in the hole will form a dynamic balance, so that the light beam can directly irradiate the hole bottom. The keyhole absorbs all the injected energy to melt the hole wall metal, which can form a particularly narrow and deep weld, and changing the welding parameters can make the weld penetration change in a large range, so deep penetration welding is more commonly used in practice.

Next, the selection of laser for welding metal is discussed. YAG laser is mostly used for metal welding, because YAG laser is more easily absorbed by metal than CO22 laser and less affected by plasma, so the welding operation is flexible. However, YAG laser is easy to produce a lot of heat loss when it works, which makes the temperature of laser cavity rise and produces laser thermal lens effect, thus reducing laser power and energy conversion efficiency. YLR fiber laser is based on optical fiber and doped with different rare earth ions, which has the advantages of small volume, low cost, high laser power, higher welding depth and speed, and is superior to YAG laser.

The process of laser welding metal hardly produces debris and waste residue, and there is no need to add adhesive. It has the advantages of high speed, high precision, small heat affected zone, large depth-width ratio and beautiful weld. It is easy to realize automation and can produce good social and economic benefits. It has become the main way of airtight packaging of metal packaging.

For plastic workpieces, traditional plastic welding mainly adopts ultrasonic welding, friction welding, vibration welding, hot plate welding and other technologies, but in actual processing, we should not only consider its sealing performance, but also prevent pollution during processing. The high precision and non-contact of plastic laser welding can just meet this requirement.