Things to be aware of when cutting with a laser engraver

A laser engraver is used for cutting, and a single lens is often used for focusing. The focal length should be selected according to the thickness of the material to be cut, taking into account both the diameter of the spot and the depth of focus. The material to be cut is thick and the depth of focus should be large to ensure that the diameter of the spot is not changed greatly in the range of the thickness of the cut, and the focal length should be larger; if the material to be cut is thin, the focal length should be smaller to reduce the diameter of the focused spot. The width of the slit is reduced to obtain a 51-inch slit. For laser cutting of a few meters of thick sheet, the focal length of the focusing mirror is 50.

 
The basic requirement for laser cutting to flow is that the air flow into the slit is large and the speed is high, so that there is sufficient oxygen to make the slit material fully exothermic and there is enough movement to spray the molten material out. These are related to the stagnation pressure of the airflow acting on the surface of the workpiece, which can be called the cutting pressure. In order to achieve high cutting speed and cut quality, the cutting pressure should be large.
 
The maximum speed melon that the laser cuts promised is based on the balance of the world and the heat transfer near the bamboo raft. Under certain cutting conditions, there is a daring cutting speed Pang Fantian. 囝 1. 16 is the upper and lower width of the incision with the change of cutting speed. If the cutting speed is too low, the material is too hot, and the slit width and material heat affected zone are too large. When the cutting speed is over the quotient, the cut slag is not cleaned into the normal cutting area.




The laser cutting process takes place on the near-vertical surface at the end of the slit. You are the ablation front. The laser and airflow enter the slit at this point, the most part of the laser energy being absorbed by the ablation front, and a portion passing through the slit or reflecting through the ablation front to the slit space. Embossed drawing  
The ablation front is heated or agglomerated by the absorbed laser and the exothermic reaction during the cutting process and is blown off by the gas stream. Part of the heat is transferred to the matrix material by heat conduction, which is consumed by radiation and is carried away by convective heat transfer. In some laser cutting processes, the above conduction, radiation and convective heat loss can be neglected. The laser energy is almost completely absorbed by the workpiece, and the energy balance of the process becomes very simple: the energy of the laser energy 1 and the exothermic reaction are all used. Heat, melt, and cut material.
 
Modern laser cutting is based on cutting gold sheets. Gold chips have a high reflectivity for lasers and a high thermal conductivity, making the actual cutting process far more complicated. Oxygen-cutting steel sheet is the most widely used laser cutting process and is a reactive melt cutting. Melt cutting with quiet gas can be seen as a special case of reaction melting cutting. Therefore, the following discussion mainly discusses the mechanism of laser reaction melting ratio cutting.
 
  An important factor in laser cutting is the absorption of the incident laser at the leading edge of the workpiece ablation, which is the basis for efficient laser cutting. The absorption of the laser depends on the polarization, mode, and convergence angle of the laser. It depends on the shape and inclination of the ablation front, as well as the nature of the material and the degree of oxidation. Therefore, it must be strictly performed according to the procedure, so that the ultimate guarantee is good. effect!