Narrow slits and small deformation of workpieces
The laser beam is focused into a very small light spot, so that the focus reaches a very high power density. At this time, the heat input by the beam far exceeds the part reflected, conducted or diffused by the material, and the material is quickly heated to the vaporization level, evaporating to form holes. As the beam and the material move linearly relative to each other, the holes continuously form a very narrow slit. The cutting edge is little affected by heat, and there is basically no deformation of the workpiece.
Auxiliary gas suitable for the material being cut is also added during the cutting process. When cutting steel, oxygen is used as an auxiliary gas to produce an exothermic chemical reaction with the molten metal to oxidize the material, and at the same time help blow away the slag in the slit. Compressed air is used to cut plastics such as polypropylene, and inert gas is used to cut flammable materials such as cotton and paper. The auxiliary gas entering the nozzle can also cool the focusing lens to prevent smoke and dust from entering the lens seat to contaminate the lens and cause the lens to overheat.
Most organic and inorganic materials can be cut by laser. In the metal processing industry, which occupies a large proportion of the industrial manufacturing system, many metal materials, regardless of their hardness, can be cut without deformation. Of course, for high reflectivity materials, such as gold, silver, copper and aluminum alloy, they are also good heat conductors, so laser cutting is difficult or even impossible. Laser cutting has no burrs, wrinkles, high precision, and is better than plasma cutting. For many electromechanical manufacturing industries, since modern laser cutting systems controlled by microcomputer programs can easily cut workpieces of different shapes and sizes, it is often preferred over punching and die pressing processes; although its processing speed is slower than die punching, it has no mold consumption, no need to repair the mold, and saves time for mold replacement, thereby saving processing costs and reducing production costs, so it is more cost-effective overall.
Non-contact processing
After focusing, the laser beam forms a very small action point with extremely strong energy, and it has many characteristics when applied to cutting. First, the laser light energy is converted into amazing heat energy and maintained in a very small area, which can provide (1) narrow straight edge cutting seam; (2) the smallest heat-affected zone adjacent to the cutting edge; (3) very small local deformation. Secondly, the laser beam does not exert any force on the workpiece. It is a contactless cutting tool, which means that (1) there is no mechanical deformation of the workpiece; (2) there is no tool wear, and there is no problem of tool conversion; (3) the hardness of the cutting material does not need to be considered, that is, the laser cutting ability is not affected by the hardness of the material being cut, and any material of any hardness can be cut. Thirdly, the laser beam is highly controllable and has high adaptability and flexibility, so (1) it is very convenient to combine with automation equipment and it is easy to realize the automation of the cutting process; (2) since there is no restriction on the cutting workpiece, the laser beam has unlimited contour cutting ability; (3) combined with a computer, the whole sheet can be arranged to save materials.
Adaptability and flexibility
Compared with other conventional processing methods, laser cutting has greater adaptability. First of all, compared with other thermal cutting methods, as a thermal cutting process, other methods cannot act on a very small area like the laser beam, resulting in wide incisions, large heat-affected zones and obvious workpiece deformation. Lasers can cut non-metals, while other thermal cutting methods cannot.
Generally speaking, the quality of laser cutting can be measured by the following 6 standards.
⒈ Cutting surface roughness Rz
⒉ Cutting slag size
⒊ Cutting edge verticality and slope u
⒋ Cutting edge radius size r
⒌ Stripe back drag n
⒍ Flatness F
