Several Common Problems and Solutions of Laser Cutting Machine
1. Perforation Technology of Metal Laser Cutting Machine
Hot cutting technology, except in a few cases can start from the edge of the board, generally on the board perforated a small hole. Previously, a punch was used to punch a hole in a laser punching compound machine, and then a laser was used to cut the hole. There are two basic methods of perforation for laser cutting machine without punching device:
Blasting Perforation - The material is irradiated by continuous laser to form a pit in the center, and then the molten material is quickly thrown away to form a hole by oxygen flow coaxial with the laser beam. The average diameter of the blasting perforation is half of the thickness of the plate. Therefore, the hole diameter of the blasting perforation of the thicker plate is bigger and not round. It is not suitable for the parts with higher processing accuracy, and can only be used on the scrap. In addition, because the oxygen pressure used in perforation is the same as that used in cutting, the spatter is larger.
Pulse Perforation - The use of high peak power pulsed laser to melt or vaporize a small amount of material, commonly used air or nitrogen as a common gas, to reduce the expansion of the hole due to exothermic oxidation, gas pressure is lower than the oxygen pressure when cutting. Each pulsed laser produces only small particle ejections, which gradually penetrate into the thick plate, so it takes several seconds to perforate the thick plate. Once the perforation is completed, the gas is replaced by oxygen for cutting. In this way, the diameter of the perforation is smaller, and the perforation is in blasting. For this reason, the laser used should not only have high output power, but also the time and space characteristics of the beam, so the general transverse flow CO2 laser can not meet the requirements of laser cutting. In addition, pulse piercing also requires a gas path control system to achieve gas type, gas pressure switching and piercing time control.
2. Analysis of Deformation of Small Holes in Metal Laser Cutting Machine
This is because the machine tool (only for high-power laser cutting machine) does not adopt the way of blasting perforation, but uses the way of pulse piercing (soft puncture), which makes the laser energy too concentrated in a very small area and burns the non-processing area, resulting in the deformation of the hole and affecting the processing quality. At this time, we should change the pulse puncture (soft puncture) mode into blasting puncture (ordinary puncture) mode in the processing procedure to solve the problem. On the contrary, the laser cutter with smaller power should adopt pulse piercing to achieve better surface finish.
3. Solution to Burr of Workpiece in Cutting Low Carbon Steel by Metal Laser Cutting Machine
According to the working and design principles, the following reasons are analyzed: the position of laser focus is incorrect, it needs to be tested and adjusted according to the deviation of focus; the output power of laser is not enough, it is necessary to check whether the laser generator works properly, if so. Normally, the output value of the laser control button is observed and adjusted; the linear speed of cutting is too slow, which needs to be increased in operation control; the purity of cutting gas is insufficient, and high-quality cutting working gas is needed; the laser focus offset needs to be tested according to the focus offset. Volume adjustment; machine tool running time is too long to appear instability, at this time need to shut down and restart.
4. Analysis of Burrs in Stainless Steel andAluminum Plates Processed by Metal Laser Cutting Machine
Considering the burr factor in cuttinglow-carbon steel, we can not simply speed up the cutting speed, because theincreasing speed sometimes leads to the situation that the plate can not be cutproperly. This kind of situation is in the process of aluminium-zinc cladding.At this time, other factors of machine tool should be consideredcomprehensively to solve, such as whether the nozzle should be replaced or not,and the unstable motion of the guide rail.
5. Analysis of Uncut Laser Penetration
After analysis, it can be found that thefollowing situations are the main causes of instability in processing: thechoice of nozzle of laser head does not match the thickness of the plate; thelinear speed of laser cutting is too fast, which requires operation control toreduce the linear speed; the error of nozzle induction is too large to guide tothe laser focus position, and the induction data of nozzle need to bere-detected, which is in cutting. It is easy to appear when cutting aluminium.
6. Solution to Abnormal Sparks in LowCarbon Steel Cutting by Metal Laser Cutting Machine
This situation will affect the cutting surface finishprocessing quality. When other parameters are normal, the following should beconsidered: the loss of laser nozzle N O ZZEL should be changed in time. In thecase of no new nozzle replacement, the cutting gas pressure should beincreased, and the threads at the connection between the nozzle and the laserhead should be loosened. At this time, the cutting should be suspended, thelaser head connection status should be checked, and the thread should bere-threaded.