Bridge position technology for improving the service life of laser nozzle in fiber laser cutting machine
The development of fiber laser cutting machine is changing with each passing day. In thin plate cutting, fiber laser cutting machine has been widely used in the industry due to its characteristics of no consumables, high speed, and exquisite processing effect. The use and maintenance of laser heads have become user contacts. One of the components with higher frequency, the laser nozzle is the most cutting-edge laser processing tool of the laser head. In the laser cutting process, under the protection of the sensor, theoretically it is impossible for the nozzle to hit the iron plate in the vertical direction. There is a certain gap between the knife and the cut iron plate. However, in practice, the nozzle is in the high temperature beam and high-speed oxygen or air. In the case of passing, it often touches or even collides with the steel plate, and the nozzle hole often has to be shut down for maintenance and replacement, which reduces the production efficiency and increases the loss of the laser nozzle.
The characteristics of the fiber laser cutting machine machine tool start from the bridge position process of cutting and layout, reducing the collision rate of the plate and the nozzle, thereby increasing the service life of the nozzle and the laser head assembly, and reducing the maintenance and replacement of parts. cost.
1Laser nozzle failure analysis
The laser nozzle is generally made of copper or copper alloy. This is a single-layer nozzle; the front surface of the nozzle is plated with a layer of chromium, which is a double layer Nozzle, the nozzle hole diameter is φ1.0～3.0mm, 5° inverted cone hole etc. are provided. Obviously, this nozzle has strong heat dissipation, is not easy to stick to slag, and is convenient to manufacture. However, the disadvantages of the nozzle manufacturing process and electromechanical performance are prone to the following failure modes: (1) The front of the nozzle is eroded, the hole diameter becomes larger or the deformed copper alloy material is soft, the melting point is low, and the nozzle surface is easy to be touched. The surface of the non-chrome-plated nozzle is easy to contact with the slag erosion. If the erosion point occurs at the edge of the inner ring of the aperture, a built-up edge (high-speed airflow cannot be blown out) will be formed, which will affect the direction and energy of the laser beam, and affect the accuracy of the slitting. Seam surface quality. After the built-up tumor becomes larger, it will fall off under the impact of high temperature and high-speed air flow. A small part of the material at the edge of the aperture will fall off. After a long time, the aperture will become larger or deformed, which will affect the focus adjustment of the laser beam.
(2) The nozzle hole is deformed, and the slag particles damage the internal lens. During the cutting process, after the laser head is collided in the vertical direction, there is a sensor to recognize and protect the shutdown; but the horizontal direction encounters the tilted steel plate, When the force is heavy, the sensor stops when the sensor senses, the nozzle bottom hole is deformed, the laser head is skewed, and the laser beam is swayed, and cutting cannot be continued; if the force is light, the sensor is not enough to sense the stop, and the nozzle hole is completely in close contact with the steel plate. Dip in the molten slag, and the high-speed airflow blows the molten slag everywhere. At this time, fine molten slag particles or vaporized metal are poured into the laser head, forming metal dust, blocking and damaging the internal lens film, affecting the laser beam passing and reducing the cutting quality . Users often have to shut down the laser head to disassemble, clean and remove dust or replace parts, adjust the focal length of the laser beam, etc., which greatly reduces the service life of consumables and increases maintenance costs.