Laser processing nozzle and laser processing equipment

Abstract

The invention discloses a laser processing nozzle which comprises a channel which extends from a nozzle inlet to a nozzle outlet and is used for allowing a laser beam and auxiliary gas to pass through, the channel comprises a contraction part and an expansion part, the intersection of the contraction part and the expansion part is a throat part, the contraction part is transited to the expansion part at the throat part, and the expansion part is connected with the contraction part. The length of the expansion part along the longitudinal axis of the channel is L1, the difference value between the radius of the cross section of an outlet of the expansion part and the radius of the throat part is L2, and the L1 and the L2 have the following function relation: L2 is greater than or equal to k * (0.0298 L12-0.5288 L1 + 3.3231), k is a correction coefficient, 0.497 lt, and L is a correction coefficient. Klt; and 0.870% of the total weight. According to the laser machining nozzle, by controlling the structure of the nozzle channel, the kinetic energy of air flow sprayed out of the nozzle is stable, the effective acting distance of the air flow is lengthened, the laser machining nozzle can adapt to the application scene where the distance between the nozzle and the acting surface is large, and the high-speed machining requirement is met.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser processing, and particularly relates to a laser processing nozzle and a laser processing equipment. Background Art

[0002] As a high-precision processing method, the cutting quality of laser cutting technology is closely related to the performance of the auxiliary gas jet. Traditional laser processing nozzles generally adopt a single-stage contraction channel or an equal-section straight cylinder structure design. Its gas jet characteristics determine that it can only achieve a qualified cutting effect under the condition that the distance between the nozzle outlet and the workpiece working surface is less than 2 mm. However, when the nozzle lift height exceeds 3 mm, the kinetic energy of the air flow ejected from the nozzle outlet decreases, resulting in ineffective discharge of the molten slag, causing process defects such as slag hanging on the cutting section and incomplete cutting, and serious cutting spatter, which is likely to burn out the protective mirror.

[0003] With the development of high-power fiber lasers and processing platforms, higher requirements are put forward for the processing efficiency of laser cutting technology. The high-speed cutting mode requires the nozzle to be lifted to a height of 5 - 15 mm from the working surface. Traditional nozzles show significant air flow diffusion phenomena under such working conditions, and the air flow energy decreases too fast to meet the requirements of high-speed cutting.

[0004] Therefore, how to maintain the air flow focusing characteristics during medium and long-distance operations and make the air flow energy output stably has become a key technical bottleneck restricting the development of laser cutting technology towards high efficiency and intelligence. Summary of the Invention

[0005] One of the purposes of the present invention is to provide a laser processing nozzle that can provide better processing effects in high-speed laser processing.

[0006] Another purpose of the present invention is to provide a laser processing equipment that can perform high-speed laser processing and has good processing effects.

[0007] In order to achieve the above purposes, the technical solution adopted by the present invention is as follows: A laser processing nozzle includes a channel extending from a nozzle inlet to a nozzle outlet for passing a laser beam and an auxiliary gas. Among them, the channel includes a contraction part and an expansion part. The intersection of the contraction part and the expansion part is a throat. The contraction part transitions to the expansion part at the throat. The length of the expansion part along the longitudinal axis of the channel is L1, and the difference between the radius of the cross-section at the outlet of the expansion part and the radius of the throat is L2. The following functional relationship exists between L1 and L2: L2≥k*(0.0298L1 2 -0.5288L1 + 3.3231) Wherein, k is a correction coefficient, and 0.497 < k < 0.870.

[0008] Preferably, the value range of k is 0.497 < k < 0.805.

[0009] As some embodiments of the present invention, the value range of L1 is 6.5 - 15.5 mm.

[0010] As some embodiments of the present invention, the cross-sectional area of the throat is S1, and the cross-sectional area at the outlet of the expansion part is S2. The ratio S2 / S1 of S2 to S1 is greater than 1.3.

[0011] Preferably, the ratio S2 / S1 of S2 to S1 is 2.5 - 2.9.

[0012] As some embodiments of the present invention, the length of the contraction part along the longitudinal axis of the channel is L m , and the length of the expansion part along the longitudinal axis of the channel is L n , L m / L n = q, and the value of q is 0.05 - 10.00.

[0013] Preferably, the value of q is 0.60 - 1.22.

[0014] As some embodiments of the present invention, the cross-sectional area at the inlet of the contraction part is S3, and the ratio S1 / S3 of S1 to S3 is less than 0.4.

[0015] As some embodiments of the present invention, a connection section is further provided at the nozzle inlet. The connection section is a straight tube channel or a channel with a gradually decreasing cross-section. The inclination of the connection section wall with respect to the longitudinal axis of the channel is greater than the inclination of the contraction part wall with respect to the longitudinal axis of the channel.

[0016] A laser processing device, including the above laser processing nozzle.

[0017] The laser processing nozzle of the present invention is used for laser processing, including but not limited to laser cutting.

[0018] Compared with the prior art, the present invention has at least the following beneficial effects: The laser processing nozzle of the present invention accelerates the low-speed air flow to high speed. By precisely regulating the nozzle channel structure, the air flow ejected from the nozzle has sufficient kinetic energy, extends the effective action distance of the air flow, and effectively avoids the occurrence of flow separation points on the workpiece cutting surface, improving the quality of laser cutting. This nozzle can adapt to application scenarios with a relatively large distance between the nozzle and the working surface, prevent collisions with the plate resulting in machine shutdown, greatly reduce the probability of the splash burning the protective mirror, reduce the influence of anti-blue light, and meet the requirements of high-speed processing. Description of the Drawings

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a side view of a laser processing nozzle in an embodiment of the present invention; Figure 2 It is a cross-sectional view of a laser processing nozzle in an embodiment of the present invention; Figure 3 It is a simulation test diagram of the gas flow energy during cutting of a traditional nozzle; Figure 4 It is a simulation test diagram of the gas flow energy during cutting of a laser processing nozzle in an embodiment of the present invention.

[0021] Among them, 1 - channel, 2 - contraction part, 3 - expansion part, 4 - throat, 5 - nozzle inlet, 6 - nozzle outlet, 7 - longitudinal axis of the channel. Specific embodiments

[0022] In the drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and cannot be understood as a limitation of this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0023] It should be noted that in this article, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such a process, article or device. Without more limitations, the element defined by the statement "including one..." does not exclude the existence of another identical element in the process, article or device including that element.

[0024] Figure 1 A side view of the laser processing nozzle of the present invention is shown. The nozzle is a rotationally symmetric body, and there is a channel in the center of the nozzle for the laser beam and gas to pass through.

[0025] Figure 2 The cross-section of the laser processing nozzle of the present invention along the central axis is shown. The laser processing nozzle includes a channel extending from the nozzle inlet to the nozzle outlet for passing a laser beam and auxiliary gas, and the channel extends from the nozzle inlet to the nozzle outlet along the nozzle central axis. The channel includes a contraction section and a divergence section. The inner diameter of the channel tapers in the contraction section and expands in the divergence section. The intersection of the contraction section and the divergence section is the throat, and the inner diameter of the channel is the smallest at the throat.

[0026] The length of the divergence section along the longitudinal axis of the channel is L1, and the difference between the radius of the cross-section at the outlet of the divergence section and the radius of the throat is L2. The following functional relationship exists between L1 and L2: L2≥k*(0.0298L1 2 -0.5288L1 + 3.3231) where k is a correction coefficient, and 0.497 < k < 0.870.

[0027] During the actual working process, the laser beam and the auxiliary gas are ejected from the channel of the nozzle together. After the low-speed gas enters the channel from the nozzle inlet, it continuously accelerates inside the nozzle and finally forms a high-speed jet at the nozzle outlet. The acceleration of the gas inside the nozzle makes the airflow ejected from the nozzle have higher energy, and due to the design of the nozzle channel structure, the airflow energy ejected from the nozzle outlet is stably and continuously output after leaving the nozzle. This enables the airflow to maintain a relatively high energy intensity within a certain length range, and even when the distance between the nozzle and the working surface is increased, the cutting effect can be ensured not to be affected, providing a strong guarantee for realizing efficient and stable laser cutting operations.

[0028] In the structure of the nozzle channel, the structural design of the divergence section has an important influence on the gas flow characteristics. The present invention accurately defines the relationship between the cross-sectional area of the throat and the cross-sectional area of the divergence section, thereby optimizing the gas flow characteristics and making the energy change of the gas after leaving the nozzle more uniform.

[0029] Figure 3 It is the airflow energy simulation test diagram of the traditional nozzle during cutting. Figure 4 It is the airflow energy simulation test diagram of the nozzle of the present invention during cutting, and the ventilation pressure is 8 bar. The figure shows the kinetic energy change of the airflow after leaving the nozzle. Among them, the redder part represents the higher kinetic energy of the airflow. Figure 3 It shows that during the elevated cutting of the traditional nozzle, when the airflow contacts the workpiece cutting surface, a flow separation point (at point A) appears in the middle of the contact surface, and the kinetic energy of the airflow in the area below the separation point is insufficient to complete qualified cutting. Figure 4It shows that the nozzle of the present invention always maintains sufficient kinetic energy during the elevated cutting process, without generating a flow separation point, and can successfully complete the elevated cutting to ensure the cutting quality.

[0030] Preferably, the value range of k is 0.497 < k < 0.805.

[0031] The value range of L1 is 6.5 - 15.5 mm. Whether the length L1 of the expansion part is too large or too small will affect the acceleration effect of the gas in the nozzle. The cross-sectional area of the throat is S1, and the cross-sectional area at the outlet of the expansion part is S2. The ratio S2 / S1 of S2 to S1 is greater than 1.3. Preferably, the ratio S2 / S1 of S2 to S1 is 2.5 - 2.9.

[0032] The length of the contraction part along the longitudinal axis of the channel is L m and the length of the expansion part along the longitudinal axis of the channel is L n L m / L n = q, and the value of q is 0.05 - 10.00. Preferably, the value of q is 0.60 - 1.22.

[0033] The cross-sectional area at the inlet of the contraction part is S3, and the ratio S1 / S3 of S1 to S3 is less than 0.4, preferably 0.1 - 0.4, and more preferably 0.15 - 0.25.

[0034] The following are the parameter characteristics of the nozzle in some specific embodiments: Table 1 Parameter characteristics of multiple embodiments of the laser processing nozzle L1 (mm) L2 (mm) <![CDATA[S1(mm 2 )]]> <![CDATA[S2(mm 2 )]]> <![CDATA[S3(mm 2 )]]> q S1 / S3 Example 1 9.00 0.90 7.07 18.09 30.96 0.67 0.23 Example 2 9.00 0.90 7.07 18.09 41.60 1.22 0.17 Example 3 9.00 1.05 7.07 20.42 32.15 0.67 0.22 Example 4 9.00 1.05 7.07 20.34 40.92 1.22 0.22 Example 5 13.50 1.50 7.07 50.24 50.24 0.67 0.39 The contraction part directly transitions to the expansion part, and there is no straight cylinder section between the contraction part and the expansion part.

[0035] An adapter section is also provided at the inlet of the nozzle. The adapter section is a straight cylinder channel or a channel with a gradually decreasing cross-section. The inclination of the wall surface of the adapter section relative to the longitudinal axis of the channel is greater than the inclination of the wall surface of the contraction part relative to the longitudinal axis of the channel.

[0036] The laser cutting nozzle of the present invention is particularly suitable for high-speed laser cutting of carbon steel.

[0037] The laser processing equipment of the present invention includes the above-mentioned laser processing nozzle. Specifically, a laser cutting processing head is equipped on the laser processing equipment, and the laser processing nozzle is installed on the processing head. The laser processing equipment also includes a laser connected to the laser cutting processing head.

[0038] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this specification.

[0039] The above embodiments only express several implementation manners of the present invention, and the description thereof is relatively specific and detailed, but it should not be construed as a limitation to the scope of the patent application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of this invention patent shall be subject to the appended claims.

Claims

1. A laser processing nozzle, characterized in that: The invention comprises a channel extending from a nozzle inlet to a nozzle outlet for passing a laser beam and an auxiliary gas, wherein the channel comprises a contraction portion and an expansion portion, the intersection of the contraction portion and the expansion portion is a throat portion, the contraction portion transitions to the expansion portion at the throat portion, the expansion portion has a length L1 along the longitudinal axis of the channel, the difference between the radius of the cross section at the outlet of the expansion portion and the radius of the throat portion is L2, and L1 and L2 have the following functional relationship: L2≥k*(0.0298L1 2 -0.5288L1+3.3231) Where k is the correction factor, 0.497 <k<0.870。 2. The laser processing nozzle according to claim 1, characterized in that: The value range of k is 0.497 <k<0.805。 3. The laser processing nozzle according to claim 1, characterized in that: The value range of L1 is 6.5~15.5mm.

4. The laser processing nozzle according to claim 1, characterized in that: The cross-sectional area of ​​the throat is S1, the cross-sectional area at the outlet of the expansion portion is S2, and the ratio of S2 to S1 (S2 / S1) is greater than 1.

3.

5. The laser processing nozzle according to claim 4, characterized in that: The ratio of S2 to S1, S2 / S1, is 2.5~2.

9.

6. The laser processing nozzle according to claim 1, characterized in that: The length of the contraction along the longitudinal axis of the channel is L m The length of the expansion portion along the longitudinal axis of the channel is L n , L m / L n =q, the value of q is 0.05~10.

00.

7. The laser processing nozzle according to claim 6, characterized in that: The value of q is 0.60~1.

22.

8. The laser processing nozzle according to claim 1, characterized in that: The cross-sectional area at the inlet of the contraction portion is S3, and the ratio of S1 to S3 (S1 / S3) is less than 0.

4.

9. The laser processing nozzle according to any one of claims 1 to 8, characterized in that: A connecting section is also provided at the nozzle inlet. The connecting section is a straight channel or a channel with a gradually narrowing cross section. The inclination of the connecting section wall relative to the longitudinal axis of the channel is greater than the inclination of the contraction portion wall relative to the longitudinal axis of the channel.

10. Laser processing equipment, characterized in that: A laser processing nozzle comprising the laser processing nozzle according to any one of claims 1 to 9.

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