1. What are the perforation methods of ultra-high power fiber laser cutting machine?

Any kind of hot cutting technique, except in a few cases, can start at the edge of the sheet. Usually, a small hole must be drilled in the board. Early laser stamping composite machines used a punch to punch a hole and then a laser to cut through the hole. With the continuous improvement of laser power and the gradual maturation of technology, laser direct drilling has become the mainstream. So what are the ways of laser cutting and punching? 1. Blasting perforation. A continuous laser is used to illuminate the material, forming a pit in the center, and then a flow of oxygen coaxial with the laser beam is used to quickly remove the molten material, forming a hole. In general, the size of the hole is related to the thickness of the plate, with the average diameter of the blasting hole being half the thickness of the plate. Therefore, the blasting hole aperture of the thicker plate is large, not round, not suitable for the parts with high processing accuracy requirements, and can only be used for scrap. In addition, because the oxygen pressure used for piercing is the same as that used for cutting, the splash is large.

2. Pulse perforation. A pulsed laser of peak power is used to melt or evaporate small amounts of material. In CNC flame cutters, air or nitrogen is usually used as an auxiliary gas to reduce hole expansion due to exothermic oxidation. The gas pressure is lower than the oxygen pressure when cutting. Each laser pulse produces only a tiny jet of particles, which deepens gradually, so it takes a few seconds to perforate a thick plate. Once the piercing is complete, the auxiliary gas is turned into oxygen for cutting. The perforation diameter is smaller and the perforation quality is better than the blasting perforation. For this reason, the laser used should not only have a high output power, but also have the temporal and spatial characteristics of the beam, so the general cross-flow CO2 laser can not meet the requirements of laser cutting. In addition, pulsed perforation requires a reliable gas-path control system to allow switching of gas types and gas pressures and control of perforation time.

3. Analysis of the perforation application technology of ultra-high power fiber laser cutting machine

In the case of pulse perforation, attention should be paid to the transition technique from pulse perforation when the workpiece is at rest to continuous cutting of the workpiece at a constant speed in order to obtain a high quality cut. Theoretically, it is usually possible to change the cutting conditions of the acceleration section, such as focal length, nozzle position, gas pressure, etc. In practice, however, it is unlikely that these conditions will change because time is short. In industrial production, it is practical to change the average laser power, the specific method is to change the pulse width. Change the pulse frequency; Change the pulse width and frequency simultaneously.

Laser cutting hole deformation how to solve? The hole deformation phenomenon in cutting is mainly because the machine tool (only applicable to high-power laser cutting machine) does not use the blasting perforation way, but adopts the pulse perforation (soft perforation) way, so that the laser energy is too concentrated in a small area, causing scratches on the non-processing area, leading to hole deformation, affecting the processing quality. At this time, we should change the pulse perforation (soft perforation) mode to the blasting perforation (ordinary perforation) mode in the machining program to solve the problem. For low power laser cutting, the opposite is true. When machining small holes, pulse perforation should be used to obtain a better surface finish.

How to solve the perforation slag treated by ultra high power fiber laser cutting machine? Slag accumulation occurs during laser drilling of thick plate. If you cut directly, the cutting quality will be very poor, and the cutting section will be very rough. At present, there are two kinds of slag reduction cutting methods commonly used in the market: slow start and increase cutting speed. Slow start cutting will affect the service life of the nozzle, thus increasing the processing cost of the customer; Increasing the cutting speed will lead to the decrease of cutting surface effect and affect product quality.

In the actual perforation cutting, it is necessary to choose the appropriate adjustment method according to the different plate thickness and its own processing requirements.