Laser cutting has the advantages of high cutting precision, fast cutting speed, low thermal effect, no pollution and no noise, and has been widely used in the automotive, marine, aerospace and electronic industries. The quality of the laser cutting process is closely related to the relative position between the laser focus and the workpiece. To ensure a reasonable relative position between the laser focus and the cutting object is one of the keys to ensure the quality of the laser cutting process. Coil Recoiler,Recoiling Machine,Coil Recoiling Machine,Metal Coil Recoiling Machine Zhangjiagang Zhong Lai Machinery Co.,Ltd. , https://www.alumajor.com
The focus position of the laser focus cannot be measured directly, but it can be detected by indirect methods. For a laser cutting system, the focus position is determined by the optical focus of the focusing lens, so that the position of the focusing lens is constant (regardless of the thermal effect of the focusing lens) under certain conditions, so that the detection of the focusing lens and the The relative position between the processing objects indirectly detects the positional relationship between the focus and the object being processed.
The relative position between the laser focal point and the object to be machined can be detected by an inductive displacement sensor and a capacitive sensor, each having advantages and disadvantages in use. Inductive sensors have a low response frequency and are not suitable for high-speed machining and imaging! In the case of dimensional processing, where non-contact detection is required, capacitive sensors have advantages such as fast response speed and high detection accuracy. However, they are non-linear during use and are easily affected by the interference of plasma clouds and spray slag generated during the laser cutting process. .
This article will systematically discuss the path of the laser focus position error in the laser cutting process and the composition of the automatic elimination error control system. On this basis, the deficiencies and overcoming methods of the two sensor detection system components as well as their practical use are discussed.
The production of focus position error during laser cutting In the laser cutting process, there are many factors that change the relative position between the focal point and the surface of the machined workpiece. The surface of the machined workpiece is uneven, the workpiece is clamped, the machine tool geometry error, and the machine tool. Deformation under load force, thermal deformation of the workpiece during machining, etc. will cause deviation of the laser focus position from the ideal given position (programmed position). Some errors (such as machine tool geometric errors) have regularity and can be compensated by quantitative compensation methods, but some errors are random errors that can only be eliminated by online detection and control. These errors are:
1.1, workpiece geometry error Laser cutting objects for the plate or cover parts, due to various? Due to the influence, the surface of the processing object has undulations, and the influence of the thermal effect during the cutting process also generates the surface deformation of the thin plate component. For the 1D laser processing, the surface of the cover member may also be uneven during the press molding process. These will produce random changes in the position and ideal position of the laser focus and the surface of the object to be machined.
1.2. Error caused by the workpiece clamping device The laser-cutting workpiece is placed on the needle-shaped worktable. Due to machining errors, wear between the workpiece and the workpiece, and laser burns, the needle bed will appear uneven and uneven. A random error in the position between the sheet steel and the laser focus is also produced.
1.3. Errors caused by programming In the process of 1D laser cutting, the machining trajectories on complex surfaces are fitted by straight lines, arcs, etc. These fitting curves and actual curves have certain errors. These errors make the actual focus and processing. The relative position of the surface of the object and the ideal programming position produce some errors. Some teaching programming systems introduce some deviations.
Laser focus position detection and control is one of the key technologies of laser cutting processing. For fast cutting processing, the accuracy and rapidity of focus position detection will directly affect the control precision and processing quality of the focus position. The capacitive sensor has high detection sensitivity and rapid response. The advantages can be overcome by the linearization of the computer system to overcome its non-linearity.
The special sensor structure is used to eliminate the impact of plasma clouds and spray slag produced during the processing on the detection results, and improve the use of the laser cutting system.