What is laser cutting processing in precision sheet metal processing plants

发布时间：2024-03-31

What is laser cutting processing in precision sheet metal processing plants and what are the main processes?

Laser cutting technology in precision sheet metal processing plants is widely used in the processing of metal and non-metallic materials, which can greatly reduce processing time, lower processing costs, and improve workpiece quality. Modern lasers have become the "sword" that people dream of pursuing to "cut iron like mud". Taking the Jinyun Laser CO2 Laser Cutting Machine as an example, the entire system consists of a control system, a motion system, an optical system, a water cooling system, a smoke exhaust and blowing protection system, etc. The CNC mode is used to achieve multi axis linkage and equal energy cutting of the laser without being affected by speed. At the same time, it supports graphic formats such as DXP, PLT, CNC, and enhances the ability to draw and process interface graphics; Adopting high-performance imported servo motors and transmission guidance structures to achieve good motion accuracy at high speeds. Laser cutting is achieved by using the high-power density energy generated by laser focusing.

Under the control of a computer, the laser is discharged through pulses to output a controlled repetitive high-frequency pulsed laser, forming a beam of light with a certain frequency and pulse width. The pulsed laser beam is transmitted and reflected through the optical path and focused on the surface of the processed object through a focusing lens group, forming fine, high-energy density light spots. The focal spots are located near the surface to be processed and melt or vaporize the processed material at high temperatures in an instant. Each high-energy laser pulse instantly sprays a small hole on the surface of an object. Under computer control, the laser processing head of a precision sheet metal processing plant moves continuously relative to the material being processed according to a pre drawn pattern, thus processing the object into the desired shape.

When cutting, a coaxial airflow with the beam is sprayed out by the cutting head, blowing out the melted or vaporized material from the bottom of the incision (note: if the blown gas reacts with the cut material in a thermal effect, this reaction will provide additional energy required for cutting; the airflow also cools the cut surface, reduces the heat affected zone, and ensures that the focusing lens is not contaminated). Compared with traditional sheet metal processing methods, laser cutting has advantages such as high cutting quality (narrow cut width, small heat affected zone, smooth cut), high cutting speed, high flexibility (can cut any shape at will), and wide material adaptability.

The main processes include the following:

1. Vaporization cutting

Under the heating of a high-power density laser beam, the speed at which the surface temperature of the material rises to the boiling point temperature is so fast that it is sufficient to avoid melting caused by thermal conduction. As a result, some materials vaporize into steam and disappear, while others are blown away as ejecta from the bottom of the slit by auxiliary gas flow. Some materials that cannot be melted, such as wood, carbon materials, and certain plastics, are cut into shape through this vaporization cutting method. During the vaporization cutting process, steam carries away melted particles and washes away debris, forming pores. During the vaporization process, approximately 40% of the material disappears as steam, while 60% of the material is expelled by the airflow in the form of droplets.

2. Melting cutting

When the power density of the incident laser beam exceeds a certain value, the material inside the beam irradiation point begins to evaporate, forming holes. Once this small hole is formed, it will act as a blackbody to absorb all the energy of the incident beam. The small hole is surrounded by a molten metal wall, and then an auxiliary airflow coaxial with the beam takes away the molten material around the hole. As the workpiece moves, the small hole synchronously moves horizontally in the cutting direction to form a cutting seam. The laser beam continues to shine along the front edge of this slit, and the melted material is continuously or pulsatively blown away from inside the slit.