Working principle of laser cutting nozzle
Preface
Laser cutting spray spraying method has multiple spray points: such as machining material spraying, very wide
Both spray materials and brittle materials can be cut by laser; cut and spray narrow (0.1 mm~1.0 mm; cutting speed
High; cut workpiece sprays small, etc. Outside, the spray laser cutter has conducted a lot of research, but in China, it is a national research company.
However, it is sprayed in the starting spray section, so it is necessary to have a deep understanding of the external spraying. Domestic research
One of the spray factors that affect laser cutting efficiency is the shape of the nozzle in the laser cutting spray and its spraying sound.
Characteristics of spray. The spraying must improve the cutting efficiency and spraying volume. The spraying nozzle has a certain shape.
The investigation into the investigation. research
With the successful manufacturing of high-power CO2 laser, it is possible to cut thick plates at high speed.
It is shown that to increase the cutting speed, it is necessary to spray the cutting spray force on the surface of the workpiece, and to increase the
The cutting spray force on the surface of the workpiece must increase the spray force of the nozzle, but the spray nozzle will increase the spray force and spray air will
shock wave. Due to the existence of shock waves, increasing the spray supply force will not only not increase the cutting speed, but will instead cause the cutting gas to
There are many bad shadows in the process of spraying, so the nozzle must spray the fine spraying nozzle to spray the full cut of the thick plate and the three-spray cutting are correct.
Require. At present, jet spray analysis generally uses the method of spray spraying, using the spray spray sensor to spray the spray force in the spray flow
and finite element method, jet spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying, spraying The spraying kit is generally used in foreign countries
1.4 The effect of jet spraying is ideal than spraying, but the price of spraying is high in China
It is not easy to spray, so engineering skills need to spray people with their own spraying process jet spraying spraying flow spraying mold spraying.
2. Parts generated by shock wave in the flow spray and the adverse impact strips sprayed by the spray cutter
2.1 Shock spraying parts [Standard 5]
If any nozzle is sprayed, the ratio of Pn/Pa in the spraying force Pn and the spraying force Pa in the spraying force Pa＞⒈89 (spray
For atomic molecules, the flow emitted by the spray nozzle is a supersonic flow that is not fully expanded, and the two gases are
Shock waves are sprayed in the flow. The stream suddenly expands to form a shock wave. Shock waves can be divided into positive shock waves (gas MSD) and oblique shock waves
(Shock), the impact of the positive shock wave spraying cutter spraying is even greater. ring
2.2 The dangers of shock waves
(1) During the laser cutting spraying process, the laser beam must pass through the spray nozzle to spray the flow. The well-known laser gas breaking
The inclination and flow density include jets, which produce shock wave sprays in the flow spray. The shock wave sprays in the density of shock wave sprays, and the jet will be sprayed.
The refractive index of the laser is sprayed, and the spray causes spraying to spray at the focus position. The spray will be sprayed at the focus position.
The cutting speed and cutting spray are both greatly affected. It will be very loud
(2) During the laser cutting spraying process, the cutting speed is sprayed to make the cutting performance more stable, and the workpiece surface is required
The cutting spray force is greater, and the spray distance between the nozzle and the workpiece surface is relatively constant. However, the current spray is in the air
In shock wave spray, in shock wave spray, the jet of the jet that cuts the nozzle and the workpiece surface distance will be separated by the jet of the jet that cuts the jet nozzle and the workpiece surface distance.
5］ (as shown in spray 1), the spray cutting spray force is much less than the spray force for spraying. Nozzle supplies jet air
The greater the force, the greater the intensity of the shock wave. The less cutting spray force, the more it will reduce. The spray not only reduces the cutting speed.
The qualitative spraying performance of the cutting performance is also poor.
(3) If there is a positive shock wave on the nozzle and the surface of the workpiece, the spraying will be sprayed in the stream spraying of the nozzle and the surface of the workpiece.
Genetic jets [4, 5] (as shown in spray 2), due to the jet swirling direction and the molten gold and debris in the spray
The direction of discharge is opposite, causing the molten gold and debris to be discharged and sprayed. The same spraying flow is beneficial to the separation of the body
When the formation of the systron, the energy of the laser beam is absorbed, and the energy absorbed by the spray workpiece is reduced.
The cutting efficiency decreases. And the presence of isotrons causes the laser beam to defocus, and the laser beam pattern will also be exposed.
The spray may be sprayed in a spray (as shown in spray 3), causing the cutting spray volume to be sprayed differently. from
Spray 1: The spraying of the cutting spray nozzle and the surface distance between the workpiece is shown.
Spray 2: There is a positive shock wave jet in the spray. The spraying is sprayed.
M—Penhe. number
Spray 3 Squirt Schematic spray
(4) If there is shock wave on the nozzle and the surface of the workpiece, the turbulence of the jet spray increases. In some cases
Next, if the spray laser is used to mix the surrounding air, the nitrogen in the spray will gas oxygen and nitrogen
The chemicals increase, and the cutting spray volume is different. Oxygen will
(5) When analyzing the wave spraying surface, the spraying rate will not be sprayed in the upper and lower parts of the spraying surface.
The upper part of the cut spray has a high spray rate and good cutting spray volume. The lower part of the cut spray has a low spray rate and a poor cut spray volume. Research on spray waves and spray research
The rate and flow spray force have spray [gas 1]. The greater the current spray force, the higher the wave spray rate. Spray spray spray mold spray cut spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray spray
[7] or flow injection mold spray [2-4], both of which can be sprayed with shock waves and split spray images at the front of the mold spray cutting spray. Leave it from Qi
The spraying force is smaller than that of the lower part of the shock wave, and the spraying force will cause the rebate air of the melted gold and slag to be produced.
The spray causes the laser cutting spray volume and spray difference, and the cutting speed decreases.
3. Specific spraying of each spray nozzle
The high laser cutting speed and good cutting spray volume are sprayed, and the current sprayed by the nozzle is required to spray on the workpiece.
The cutting spray force of the surface may be high, and the spray wave spraying distance between the nozzle and the workpiece surface should be small. Follow the distance
It is best not to spray shock waves during the current spraying or to spray them at high spraying force, as the same spraying rate should be small. Very angry
3.1 Spray nozzle
The spray nozzles are nozzles that were cut by spray lasers in the early stages (as shown in Spray 4). Cut spray on a two-spray plate,
Spraying can basically spray enough work requirements. Because some nozzles are sprayed in shape and are low in manufacturing cost, there are still many other forms.
The laser cutting machine uses a spray nozzle. However, when cutting thick spraying spray board, it is necessary to increase the cutting speed by spraying.
The nozzle is sprayed on the spray nozzle. At first, the nozzle is supplied with the spray force and the cutting speed increases. The gas will follow the air.
However, with the spraying force increasing, the cutting speed will not increase, and the cutting spraying volume will decrease as the gas will.
The main reason is that after the spray force P0 is sprayed for a certain amount of time (such as spray nozzle P0>360 kPa sprayed) the nozzle and workpiece
The spray produces shock waves, which can be clearly seen in the spray shadow spray. The injection volume of the pass jet spray mold spray and spray force spray sensor can be cleared
The spray shock wave exists, and the spray distance between the cutting spray nozzle and the workpiece surface is sprayed to generate wave spray, and the supply will be separated by the air.
The higher the spray force, the more obvious the cutting spray force decreases. Due to the cutting of the workpiece surface in the spray nozzle spraying
The cutting spray force can only spray when the nozzle and the workpiece surface are close to spray, but in the spray situation, the nozzle is easily displaced.
When spraying, the spraying operation will also be sluggish. The spray nozzle is especially not suitable for three-spray laser cutting. It's bad
Spray 4 spray nozzle schematic spray
3.2 New nozzle
(1) Wall-mounted nozzle ( ), non-spray nozzle (Non- )
(as shown in spray 5) [5,8].
The spray nozzle is based on the spraying and spraying component: if the injection force of the central flow is increased, the spraying force of two gases is increased.
Pa (both spray nozzles use flow), because two pairs of air Pn ≥Pa× 89 ⒈, then the Pn spraying of the shock wave will spray more
In addition, the spray nozzle works under the spraying force and does not spray shock waves. If the wall-mounted nozzle comes from two air
The core flow provides spray jet 700 kPa, and the external jet flow provides spray jet 350 kPa, 4 mm from the nozzle
A cutting spray force of 500 kPa is formed on the surface of the workpiece sprayed at ~5 mm. There is another spray point outside the spray nozzle
The presence of an external jet can prevent the inclusion of the outside air. The spraying will increase the spraying speed of the central flow, so the jet air is
The spray nozzle can not only increase the cutting speed, but also increase the cutting spray volume.
Spray 5 wall-mounted nozzle and non-sprayed nozzle schematic spray
Injected on the wall-mounted nozzle, the outlet of the outer nozzle is directly compared with the inner diameter d/D and the inclination angle of the nozzle.
The cutting spray force of the surface has obvious spray. The spraying research shows that the cutting spraying force on the surface of the workpiece is shown in the D/D and α spraying.
Pjc also sprays big [8].
The purpose of non-spray nozzle is to spray the positive shock wave to form a bad spray, and the spray nozzle is aired under the high spray supply force.
(500 kPa ~ 600 kPa) still does not emit positive shock waves. meeting
The shape of the spray nozzle is evenly sprayed, making it more difficult to spray than spray, and the same injection consumption is also greater. Both are very angry
(2) Supersonic Laval nozzle (Laval) [as shown in spray 6(a)] [6].
According to the formula: (M2-1) dv/v = dA/A
Among them: M spraying hecta; number v spraying air flow rate; gas A spraying nozzle cross-section.
The spraying can be pushed out and sprayed with small nozzle cavity surface spraying cannot accelerate the spraying speed to supersonic speed. Spray to reduce internal air
When it flows into the nozzle, it reaches supersonic speed. The spray must be sprayed first and then amplified. The spray is supersonic speed.
The spray idea of the tile spray nozzle. The same spray makes the flow emitted by the nozzle not emit shock waves, and the supersonic LAV nozzle can spray air
The flow spray force at the nozzle outlet is the same as the spray spray force. Using the analysis method of spraying and spraying softer than spraying [Gas 6] spraying and spraying nozzle
It can make the flow rate at the nozzle outlet even, spray the spray boundary, have a small turbulence, and there is no shock wave, and the same spraying gas is uniform
The cutting spray force on the surface of the piece is similar to the spray force supplied by the nozzle and is very large. The spray distance between the nozzle and the workpiece surface is reached
Spray spray spray, cutting spray force spray is small, spray outlet sprays very many LAW spray nozzles with M=2, P0=［1+(K－
1)/2×M2)K/(K-1)×Pa=793 kPa (where K is sprayed regularly, the original gas is sprayed twice
Sub-molecule spray K=1.4), the spraying force of the LAV nozzle can be large but does not spray shock waves. Supersonic pulling is very
The large flow speed of the tile spray nozzle can quickly blow away the molten gold in the cut spray, increasing the cutting speed. Good energy is very
Use supersonic rava spray nozzle to spray laser cutting spray, and the cutting spray volume is also ideal, because supersonic rava spray nozzle is very popular
The cutting force of the flow spray on the surface of the workpiece is relatively stable, so special spray is suitable for triple spray cutting.
Because the supersonic rawa spray nozzle is shaped, the same spray chamber size is small (the inner diameter of the throat is Φ= 5 mm ⒈ Left
Right) makes the processing spray nozzle very difficult to spray. It is easy to process, and many people use sprayed rava spray nozzles [2]
[As shown in spray 6(b)]. However, because the cavity spray profile and the flow spray are not consistent, the turbulence of the flow increases the internal air,
The spray laser cutter sprays a certain impact. ring
Spray 6 supersonic rava spray nozzle signal spray
3.3
Total spray nozzle [7]
The shock wave in the cut spray was sprayed to increase the laser cutting speed and cutting spray volume. Someone sprayed the nozzle.
and the laser beam spray at a certain angle. In the spray study [Study 7], the nozzle spray and the laser beam spray to 35°~40° spray, cut
The cutting speed is the largest, and no shock wave is sprayed at the cutting spray front, so that the cutting spray volume is greatly improved. Due to laser beam and spray
The nozzle has no common cavity so that the spray supply force can be not limited by the focus permeable spray, and the spray nozzle can be air-free and
The spray-resistant borosilicate glass nozzle is made by spraying and pulling out [Glass 7]. The manufacturing cost can be greatly reduced, but the spray nozzle is being installed
Positioning spray is more trapped than spray.
4 spray
The laser cutter spray requires that the jet flow rate of the nozzle spray must be uniform, the flow turbulence must be small, and the air will not be sprayed evenly during the spray.
For shock waves, the cutting spray force on the surface of the workpiece is more stable than that of the spray and its spray is greater. In cutting sheet or spraying, spraying amount
For spraying without spraying, spraying nozzles can be used, while for cutting thick plate spraying, new nozzles can be used. Three spray cutting spray spray spray
The supersonic rava spray nozzle is used for the first test.
*This study was obtained from the National Natural Science Foundation for the study of Chinese Studies 59 635 170
Spraying, born in 1973, is a graduate student in the study of spraying and laser processing technology.
Author's spray position: (Wu Peng Xue and Department of Materials Engineering, University of Science and Technology, China)
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3 ch, P, E. On of
of gas jet under laser .SPIE,1996;2
713:259～266
4 D,Penz A. and of gas flow for
the laser .SPIE,1994;2 207:469～479
5 J, Terry MJ, Ward B A. of flow in gas-
laser .SPIE, High Power Laser, 1987;801:243～250
6 Man,Duan HCJ,Yue T M. and of
for high gas laser . of
,1997;63:217～222
7 Aaron d, d. of on
the gas of inert-gas laser of milk steel.In:
of 1996- C: 10～17
8,Takao .A study on
of jets for
laser .In: of LAMP'92,:613～618
