CNC laser cutting machine is a machine tool that uses the laser as a tool (cutter) to cut and process the workpiece.
The development of laser-cutting machine is related to laser technology.
The laser has experienced three generations of development from the original YAG (solid-state laser), CO2 (carbon dioxide laser) to the current mainstream fiber laser.
This post mainly introduces the CO2 numerical control laser cutting machine and fiber laser cutting machine.
Laser cutting is an advanced and widely used cutting technology in current material processing. It is a thermal cutting method. It uses high-energy density laser beam as a “cutting tool” to cut materials.
The high-power density laser beam irradiates the workpiece to make the irradiated material rapidly reach the ignition point or melt and ablate.
At the same time, the molten material is blown away with the help of the high-speed air flow coaxial with the beam to complete the workpiece cutting.
CNC laser cutting machine has the advantages of precision manufacturing, special-shaped processing, flexible cutting, one-time forming, fast speed, high efficiency, etc.
It has solved many problems that cannot be solved by conventional methods in industrial production.
The emergence of laser cutting machine has epoch-making significance for the development of the industry.
Laser can cut most metal and nonmetal materials.
In the electrical manufacturing industry, it is mainly used for sheet metal switch cabinet processing;
In the transport machinery industry, it is mainly used for the manufacturing of transport machinery, transport vehicles and loading and unloading machinery;
In the petrochemical industry, it is mainly used to cut the oil screen pipe;
In the automobile manufacturing industry, it is mainly used to cut the body sheet with complex shape and various curved parts, including plane cutting and three-dimensional cutting;
In the construction machinery manufacturing industry, it is mainly used for the processing of mechanical structural parts;
In the medical device industry, it is mainly used in the manufacturing of medical machinery, which can meet the requirements of precision, safety, surface roughness and other aspects of medical machinery;
In the decoration industry, it is mainly used to cut the decoration of various public leisure places, such as hall wall decoration, advertising signs, etc;
In the packaging industry, it is mainly used to process packaging boxes of various shapes and sizes.
The hardware of the laser cutting machine is mainly composed of the bed, beam, worktable, laser, cutting head, voltage stabilizer, water cooler, electric control cabinet, and air source (oxygen, nitrogen, air).
The system includes electrical system, mechanical system, gas path system, optical system, hydraulic system, lubrication system, and cooling system.
It is automatic equipment integrating machinery, light, electricity, gas, and liquid.
The processes used in machine tool manufacturing include bending, welding, machining, assembly, etc.
The mechanical transmission structure includes lead screw nut, gear rack and synchronous belt. The mechanical transmission is mainly gear rack transmission.
The main reason is that the instantaneous transmission of gear transmission is accurate, can withstand heavy load, and has high efficiency.
The CO2 numerical control laser cutting machine developed and produced by our company is shown in Fig. 1.
The machine tool includes the mechanical part to realize the X, Y and Z axis movement and the workbench for placing the processed plates (common is the single-table toothed plate workbench and the sprocket drive exchange workbench).
The gantry suspension structure is adopted. The transmission part is driven by the large-lead lead screw.
The beam carries out the Y-axis movement on the fixed beam, and the follow-up sliding seat carries out the X-axis movement on the beam.
The cutting head can move up and down (Z axis) relative to the plate on the follow-up slide.
Fig. 1 Outline drawing of CNC laser cutting machine
Laser is the device that produces laser light source and is the core component of a laser cutting machine.
The emission principle of CO2 laser is shown in Fig. 2.
The external gas is composed of carbon dioxide, nitrogen and helium, which is filled into the resonant cavity.
The laser is generated by a high voltage of 40000 volts.
The laser circulates between the tail mirror, the refractor and the front mirror, and finally outputs the laser beam from the front mirror.
The advantages of the CO2 numerical control laser cutting machine are that it can cut stainless steel, the stainless steel section is fine, and it can also cut non-metallic materials (such as acrylic, organic glass, etc.).
The disadvantage is that its photoelectric conversion rate is not high, ranging from 8% to 12%, the power consumption is high, the equipment maintenance cost is high, the dust brought by the external gas will accumulate on the lens to produce burn marks, and the cost of lens replacement is high.
With the development of a new generation of fiber lasers, CO2 lasers are gradually eliminated in the industrial field.
The optical fiber laser cutting machine developed and produced by our company is shown in Fig. 2, with a gantry structure.
The transmission part is driven by gear and rack.
The cross beam moves in the X-axis on the bed, and the slide seat moves in the Y-axis on the cross beam.
The cutting head is installed on the slide plate of the slide seat, and the Z-axis movement is carried out through the lead screw or module.
Fig. 2 Schematic diagram of emission principle of CO2 laser
Fig. 3 Outline drawing of laser cutting machine
The light emitting principle of the fiber laser is shown in Fig. 4.
The laser is composed of modules, which represent a section of power, and the total power is synthesized by adding the modules.
Inside the module is the pump source. The pump light from the pump source generates a fiber through the coupler to emit laser.
Fig. 4 Schematic diagram of optical fiber laser emission principle
The advantages of the fiber laser cutting machine are that the photoelectric conversion rate reaches 25%, the power consumption is low, the gain medium is rare earth elements, and the equipment cost is low.
The disadvantage is that the stainless steel section cut by the CO2 numerical control laser cutting machine is rough, and the sealing requirements of the cutting head assembly are high.
Laser technology has undergone several major changes.
At present, there are still many technical difficulties to be overcome in the industry, which will be developed from the following four aspects: high-speed and high-precision machine tools, cutting head structures capable of withstanding high power, piercing technology and intelligent loading and unloading and sorting and stacking of machine tools.
The laser power is getting higher, and the sheet cutting speed can reach 80m/min. However, due to the influence of the accuracy and rigidity of the machine tool, it is difficult to maintain high precision cutting at high speed, so the machine tool structure and control system will be the key direction of the future research and development of the main engine factory.