CO2 laser cutting detailing electromechanical integration of key technologies

CO2 laser cutting several key technologies is optical, mechanical and electrical integration, integrated technology. Parameters, machine performance and precision CNC system with a laser beam directly affect the efficiency and quality of laser cutting. Especially for high cutting accuracy or greater thickness of the part, you must understand and resolve the following key technologies:
1, focus position control technology:
Laser cutting is one of the advantages of high energy density beam, typically> 10W / cm2. Since the energy density 4 / πd2 proportional, so the focus spot diameter as small as possible, so as to produce a narrow kerf; and focal depth is proportional to the focal spot diameter and also the lens. Focusing lens focal depth is smaller, the smaller the diameter of the focus spot. But cutting spatter lens from the lens workpiece too easily damaged, so the general high-power CO2 laser cutting is widely used in industrial applications 5〃 ~ 7.5〃 “(127 ~ 190mm) focal length. The actual focal spot diameter 0.1 ~ 0.4mm between. For high-quality cutting, the effective depth of focus and the lens diameter and also cut material concerning, for example by cutting carbon 5〃 lens, the focal depth is within the range of the focal length of + 2%, which is about 5mm. So the focus control with respect to the cut surface of the material is important to take into consideration the position of the cutting quality, cutting speed and other factors, in principle, “Metallic Materials 6mm, the focus is on the surface;> 6mm steel, and focus on the surface;> 6mm stainless steel focus specific size is determined by the experiments below the surface.
Simple method to determine the focus position in the industrial production of three ways:
(1) Print method: the cutting head from the top down movement in the plastic plate laser beam printer, print the smallest diameter of the focus.
(2) the swash plate method: a vertical axis at an angle of plastic plates pull it horizontally, looking for the smallest of the laser beam focus.
(3) Blue Spark method: remove the nozzle, blowing air, the pulsed laser in a stainless steel plate, the cutting head from the top down motion until the blue spark is maximum focus.
For light path cutting machine, since the beam divergence angle, cut the proximal and distal length of time the process is different, there are some differences to focus in front of the beam size. The larger the diameter of the incident beam, the smaller the diameter of the focus spot. In order to reduce the beam size changes due to changes brought about before the focus of the focus spot size, domestic and foreign manufacturers of laser cutting system provides some special means for users to choose:
(1) collimator. This is a commonly used method in which the output of CO2 laser tube plus a parallel light beam expander process, after the beam diameter of the beam expander becomes larger divergence angle becomes smaller, so that within the proximal and distal cutting operating range before focusing beam size close to the same.
(2) adding a separate lower shaft moving the lens in the cutting head, and control it from the material to the nozzle surface (standoff) of the Z-axis is two separate parts. When moving the machine table or the optical axis, the beam axis from proximal to distal F also move the beam diameter of the focused spot is consistent throughout the processing area. As the picture shows.
(3) controls the focus lens (usually metal reflector focusing system) of water pressure. If the focus before leaving the beam size smaller focus spot diameter becomes large kwt_8wt, automatic control of water pressure to change the focus of curvature of the focal spot diameter becomes smaller.
(4) increase x, y direction compensating optical system on the light path cutting machine. That shortens the compensating optical path when cutting the distal end of the optical path increases; conversely reduced when cutting the proximal end of the optical path when the compensating increase in the optical path, the optical path length in order to maintain consistency.

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