Laser cutting accuracy often affects the quality of the cutting process. If the accuracy of the laser cutting machine deviates, the quality of the cut product will be unqualified. Therefore, how to improve the accuracy of the laser cutting machine is the primary issue for laser cutting practitioners.
1. What is laser cutting?
Laser cutting is a technology that uses a high-power density laser beam as a heat source and performs cutting by relative movement with the workpiece. Its basic principle is: a high-power density laser beam is emitted by a laser, and after being focused by the optical path system, it is irradiated to the surface of the workpiece, so that the temperature of the workpiece is instantly raised to a temperature higher than the critical melting point or boiling point. At the same time, under the action of laser radiation pressure, a certain range of high-pressure gas is generated around the workpiece to blow away the melted or vaporized metal, and cutting pulses can be continuously output within a certain period of time. As the relative position of the beam and the workpiece moves, a slit is finally formed to achieve the purpose of cutting.
Laser cutting has no burrs, wrinkles, and high precision, which is better than plasma cutting. For many electromechanical manufacturing industries, modern laser cutting systems with microcomputer programs can easily cut workpieces of different shapes and sizes, so they are often preferred over punching and die pressing processes. Although its processing speed is slower than die punching, it does not consume molds, does not need to repair molds, and saves time in replacing molds, thereby saving processing costs and reducing product costs. Therefore, it is more economical in general.
2. Factors affecting cutting accuracy
(1) Spot size
During the cutting process of the laser cutting machine, the light beam is focused into a very small focus by the lens of the cutting head, so that the focus reaches a high power density. After the laser beam is focused, a spot is formed: the smaller the spot after the laser beam is focused, the higher the laser cutting processing accuracy.
(2) Workbench accuracy
The workbench accuracy usually determines the repeatability of laser cutting processing. The higher the workbench accuracy, the higher the cutting accuracy.
(3) Workpiece thickness
The thicker the workpiece to be processed, the lower the cutting accuracy and the larger the slit. Since the laser beam is conical, the slit is also conical. The slit of a thinner material is much smaller than that of a thicker material.
(4) Workpiece material
The workpiece material has a certain influence on the laser cutting accuracy. Under the same cutting conditions, the cutting accuracy of workpieces of different materials is slightly different. The cutting accuracy of iron plates is much higher than that of copper materials, and the cutting surface is smoother.
3. Focus position control technology
The smaller the focal depth of the focusing lens, the smaller the focal spot diameter. Therefore, it is very important to control the position of the focus relative to the surface of the cut material, which can improve the cutting accuracy.
4. Cutting and perforation technology
Any thermal cutting technology, except for a few cases where it can start from the edge of the plate, generally requires a small hole to be punched in the plate. Earlier, on the laser stamping composite machine, a punch was used to punch a hole first, and then the laser was used to start cutting from the small hole.
5. Nozzle design and airflow control technology
When laser cutting steel, oxygen and the focused laser beam are shot to the cut material through the nozzle, thus forming an airflow beam. The basic requirements for the airflow are that the airflow entering the incision should be large and the speed should be high, so that sufficient oxidation can fully exothermic reaction of the incision material; at the same time, there is enough momentum to eject the molten material.
Post time: Aug-09-2024
