Laser cutting is to use a focusing mirror to focus the laser beam on the surface of the material, so that the material melts, vaporizes, ablates, and at the same time uses the compressed gas coaxial with the laser beam to blow off the molten material, and makes the laser beam and the material move relative to each other along a certain trajectory, thus forming a certain shape of the slit to complete the cutting of the material. Laser cutting has the advantages of high precision, narrow slit, smooth cutting surface, fast speed, good processing quality and wide processing materials. At present, laser cutting technology has been widely used in many fields. Complete sets of electrical enclosures are mostly sheet metal parts, laser cutting has become a common processing method in the sheet metal industry because of its low processing cost, high efficiency, and many types of processing materials. However, the sweet melon bitter, there is no whole country, its processing process attached to the slag, the associated burr but to the site management personnel too much trouble.
The cause and influence of burr in laser processing
By understanding the working principle and daily practice of laser cutting, it is concluded that there are six main reasons for burrs:
(1) The deviation of the upper and lower position of the laser beam focus causes the energy to be not concentrated, the workpiece gasification is not sufficient, the slag accumulation is not easy to fall off, and it is easy to produce burrs;
(2) Laser output power is not enough to effectively evaporate metal, resulting in a large number of slag and burrs;
(3) The auxiliary gas type, purity and blowing pressure of the laser cutting machine do not meet the requirements, causing burrs;
(4) The cutting speed is too slow when laser cutting works, which destroys the surface quality of the cutting surface and produces burrs;
(5) The working time of the laser cutting machine is too long, which causes the working state of the equipment to be unstable and will also cause burrs;
(6) Laser cutting equipment is insufficient, such as the laser base sawtooth tray depth is small, taper is insufficient, so the contact area with the plate is too large, resulting in laser breakdown blocked during processing, gas flow obstruction, easy to produce slag adhesion, slag rebound, the formation of burrs
The existence of burrs in the corners of the workpiece will seriously affect the subsequent bending, welding and assembly accuracy, and there are certain safety risks for the operators. If the burr workpiece is applied to the air box of the ring cabinet produced by our company, it will have a great impact on the air tightness; When used in electrical systems, it will also cause circuit short circuit or damage the magnetic field due to burr falling off, affecting the normal operation of the system or bringing other hazards.
Method of preventing burr in laser processing
Adjust equipment parameters
According to different processing materials repeatedly adjust its power, air pressure, flow, focal length, feed speed and other parameters until the best state, save the recorded data to facilitate subsequent batch processing, only relying on the parameters provided by the machine is not cut out the exquisite workpiece.
Selective auxiliary gas
The application of auxiliary gases will also affect the processing quality, so different auxiliary gases should be selected according to different processing materials. Such as cutting stainless steel, it is recommended to use nitrogen as an auxiliary gas, nitrogen is often called an inert gas, laser processing nitrogen not only prevents the laser cutting of the burst point phenomenon, but also makes the heated end face will not be oxidized instantaneously, the cut end face will be more smooth and bright. The purity of the gas is also very important, try to choose high purity gas.
Check equipment parts
For the equipment that has been used for a long time, the processing quality will also be reduced due to the aging, pollution and damage of its key accessories, resulting in burrs. If the lens is polluted by oil, there are small cracks, and the cutting nozzle is damaged, it will affect the transmission of laser power. These can be judged by observing whether the light spots formed are rounded. If the light spots are rounded, the transverse distribution of laser energy is uniform and the cutting quality is high. Cutting quality can also be guaranteed by regular inspection of key components.
Optimize equipment structure
In actual production, the equipment structure can be improved according to the different workpieces processed. If the contact area between the serrated tray and the plate of the laser base is too large, it is easy to produce burrs, which can reduce the taper and increase the depth of the teeth according to the specific situation.