Compared with the traditional oxyacetylene, plasma cutting technology, laser cutting speed, narrow kerf, heat-affected zone of small good vertical, cutting edge, cutting edge is smooth, and many types of materials that can be laser cut, including carbon steel, stainless steel, alloy steel, wood, plastic, rubber, cloth, quartz, ceramic,glass, composites, etc. With the development of market economy and the rapid development of science and technology, laser cutting technology has been widely used in automotive, mechanical, electrical, hardware and electrical fields. In recent years, laser cutting technology is developing at an unprecedented rate, are growingat a rate of 15%~20% per year. Since 1985, and is growing at an annual rate of nearly 25%. At present, the laser cutting technology in China's overall level comparedwith the advanced countries, there is a small gap between, and laser cutting technology in the domestic market has broad prospects and huge application.
Laser cutting machine in the process of cutting, beams focused by a lens of the cutting head into a very small focus, focus high power density, including cutting headis fixed on the z axis. At this time, the beam input far more than are materials reflecting, parts of conduction and diffusion of heat, quickly heated to melting and vaporization temperature of materials at the same time, a high-speed airstream fromthe coaxial or non-concentric side will melt and vaporize the material, out cutting hole is formed. With the focus and the relative motion of the material, the width of the hole forming a continuous narrow kerf, material cutting.
At present, the laser cutting machine is used in the outer optical part flying opticalsystem. Emitted from the laser beam reflector 1, 2, 3 to the cutting head on the focusing lens, focusing on the material surface form the spot. Reflective lenses 1 fixed to the fuselage still; beam reflectors x 2 along with the beam movement to movement; reflectors on the z axis 3 and y to the z shaft movement movement. It is easy to see from the diagram, in the process of cutting, as the beam x movement, partof y to the z axis movement, the length of the light path is changing.
At present, the civilian laser generator due to cost reasons, issued by the laser beam has a certain degree of divergence, "cone-shaped". When the "cone" in heightchanges (equivalent to the optical path length of laser cutting machine), the lens surface of the beam cross-sectional area change. In addition, the wave nature of light, so the inevitable phenomenon of diffraction, diffraction beam propagation in a laterally expanded, a phenomenon present in all optical systems, to determine thetheoretical limits of these systems in terms of performance. Due to Gaussian beamis "cone-shaped" diffraction of the light wave and, when the optical path length changes, acting on the surface of the lens the beam diameter change, this focus cancause changes in the size and depth of focus, but had little effect on focus. If the focus changes in the size and depth of focus, in a continuous process, inevitably had a significant impact on processing, for example, will result in cutting kerf width isinconsistent, at the same cutting power will cut through erosion or plate