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 area of the cross section of the throat part is S1, the area of the cross section of the outlet of the expansion part is S2, and the following function relation exists between S1 and S2: S2 < = k * (-0.0171 * S12 + 1.3802 * S1-0.8931), k is a correction coefficient, 1.147 lt, S12 is a correction coefficient, and S12 is a correction coefficient. Klt; and 1.318. According to the laser machining nozzle, low-speed airflow is accelerated to high speed, airflow sprayed out of the nozzle is stably and continuously output by precisely regulating and controlling the channel structure of the nozzle, the airflow breaking phenomenon is effectively avoided, the effective action distance of the airflow is prolonged, and the high-speed machining requirement is met.

Description

Technical Field

[0001] The invention belongs to the technical field of laser processing, and in particular relates to a laser processing nozzle and 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 beam. Traditional laser processing nozzles generally adopt a single-stage contraction channel or a straight cylinder structure with equal cross-section. The gas beam characteristics determine that it can only achieve a qualified cutting effect when the distance between the nozzle outlet and the workpiece action surface is less than 2mm. However, when the nozzle is lifted to a height of more than 3mm, the gas ejected from the nozzle outlet will be broken and unevenly distributed, resulting in the failure of effective discharge of slag, resulting in process defects such as slag hanging on the cutting section and incomplete cutting, and the cutting spatter is serious, which can easily burn the protective mirror.

[0003] With the development of high-power fiber lasers and processing platforms, laser cutting technology has put forward higher requirements for processing efficiency. High-speed cutting mode requires the nozzle to be raised to a height of 5-15mm from the working surface. Traditional nozzles show significant airflow diffusion under such working conditions, and the airflow energy decreases too quickly, which cannot meet the requirements of high-speed cutting.

[0004] Therefore, how to maintain the focusing characteristics of the airflow during medium and long-distance operations so that the airflow energy is 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 objects of the present invention is to provide a laser processing nozzle which can provide better processing effect in high-speed laser processing.

[0006] A second object of the present invention is to provide a laser processing equipment that can perform high-speed laser processing and has a good processing effect.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is: A laser processing nozzle 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 cross-sectional area of ​​the throat portion is S1, the cross-sectional area at the outlet of the expansion portion is S2, and S1 and S2 have the following functional relationship: S2≤k*(-0.0171*S1 2 +1.3802*S1-0.8931) Where k is the correction factor, 1.147 <k<1.318。

[0008] Preferably, the value range of k is 1.147 <k<1.217。

[0009] As some embodiments of the present invention, the value range of S1 is 3~20mm 2 .

[0010] As some embodiments of the present invention, an average inclination angle of an inner wall surface of the expansion portion relative to the longitudinal axis of the channel is greater than 0.5° and less than 10°.

[0011] Preferably, an average inclination angle of the inner wall surface of the expansion portion relative to the longitudinal axis of the channel is greater than 2° and less than 5°.

[0012] As some embodiments of the present invention, the length of the contraction portion 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.

[0013] Preferably, the value of q is 0.50~0.78.

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

[0015] As some embodiments of the present invention, a connecting section is further provided at the nozzle inlet, and the connecting section is a straight cylindrical channel or a channel with a gradually shrinking cross-section, and the inclination of the connecting section wall relative to the longitudinal axis of the channel is greater than the inclination of the contraction section wall relative to the longitudinal axis of the channel.

[0016] Laser processing equipment includes the above-mentioned 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 airflow to high speed, and through precise control of the nozzle channel structure, the airflow ejected from the nozzle is stably and continuously output, effectively avoiding the phenomenon of airflow interruption and extending the effective action distance of the airflow. The nozzle can adapt to application scenarios with a large distance between the nozzle and the action surface, prevent the machine from stopping due to collision with the plate, greatly reduce the probability of spatter burning the protective mirror, reduce the impact of reflected blue light, and meet the needs of high-speed processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 is a side view of a laser processing nozzle in one embodiment of the present invention; Figure 2 is a cross-sectional view of a laser processing nozzle in one embodiment of the present invention; Figure 3 This is a simulation test diagram of the traditional nozzle airflow energy; Figure 4 This is a test diagram of the airflow energy simulation of the laser processing nozzle in one embodiment of the present invention. Among them, 1-channel, 2-contraction part, 3-expansion part, 4-throat, 5-nozzle inlet, 6-nozzle outlet, 7-longitudinal axis of the channel. DETAILED DESCRIPTION

[0021] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of the present invention, it should be understood that the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, and are 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 direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limitations on this patent. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0022] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, article or device. In the absence of more restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, article or device including the element.

[0023] Figure 1 The side view of the laser processing nozzle of the present invention is shown. The nozzle is a rotationally symmetrical body, and a channel for the laser beam and gas to pass through is provided in the center of the nozzle.

[0024] Figure 2The 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 the laser beam and the auxiliary gas. The channel extends from the nozzle inlet to the nozzle outlet along the nozzle central axis. The channel includes a contraction portion and an expansion portion. The inner diameter of the channel gradually decreases in the contraction portion and gradually increases in the expansion portion. The intersection of the contraction portion and the expansion portion is the throat portion, and the inner diameter of the channel is the smallest in the throat portion.

[0025] The cross-sectional area of ​​the throat is S1, and the cross-sectional area at the outlet of the expansion portion is S2. S1 and S2 have the following functional relationship: S2≤k*(-0.0171*S1 2 +1.3802*S1-0.8931) Where k is the correction factor, 1.147 <k<1.318。

[0026] In the actual working process, the laser beam and auxiliary gas are ejected from the channel of the nozzle together. After the low-speed gas enters the channel from the nozzle inlet, it continues to accelerate inside the nozzle, and finally forms a high-speed jet at the nozzle outlet. The gas is accelerated inside the nozzle, so that the airflow ejected from the nozzle has 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, avoiding sudden changes and interruptions in the airflow energy. This allows the airflow to always maintain a high energy intensity within a certain length range, and even if the distance between the nozzle and the action surface is increased, it can ensure that the cutting effect is not affected, providing a strong guarantee for achieving efficient and stable laser cutting operations.

[0027] In the structure of the nozzle channel, the structural design of the expansion part 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 expansion part, thereby optimizing the gas flow characteristics and making the energy change of the gas after leaving the nozzle more uniform.

[0028] Figure 3 This is a simulation test diagram of the airflow energy of a traditional nozzle. Figure 4 This is a simulation test diagram of the airflow energy of the nozzle of the present invention, and the ventilation pressure is 8 bar. The figure shows the change of kinetic energy of the airflow after leaving the nozzle, wherein the redder the part, the higher the kinetic energy of the airflow. Figure 3 After leaving the nozzle, the airflow expands rapidly, and the kinetic energy increases rapidly. However, after excessive expansion, a compression wave is generated, causing the airflow velocity to drop sharply, and the airflow energy is interrupted, and the energy distribution is extremely uneven. The length h in the figure represents the distance where the airflow maintains a high kinetic energy and can effectively perform laser cutting, that is, the effective kinetic energy section. In this example, Figure 3The effective kinetic energy section length of the conventional nozzle shown is 10 mm, but under the same ventilation conditions, Figure 4 As shown, the effective kinetic energy section length of the nozzle in the embodiment of the present invention reaches 25 mm, which is significantly longer than that of the traditional nozzle, and the effective range is significantly increased. Even if the distance between the nozzle and the effective surface is raised, a stable cutting effect can be guaranteed.

[0029] Preferably, the value range of k is 1.147 <k<1.217。

[0030] The value range of S1 is 3~20mm 2 If the area of ​​S1 is too large or too small, it will affect the acceleration effect of the gas in the nozzle.

[0031] An average inclination angle (α) of the inner wall surface of the expansion portion relative to the longitudinal axis of the channel is greater than 0.5° and less than 10°, preferably greater than 2° and less than 5°.

[0032] 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. Preferably, the value of q is 0.50~0.78.

[0033] The cross-sectional area at the entrance of the contraction portion is S3, and the ratio of S1 to S3 (S1 / S3) is less than 0.4, preferably 0.2-0.4, and more preferably 0.25-0.35.

[0034] The following are the various parameter characteristics of the nozzle in some specific embodiments: Table 1 Parameter characteristics of multiple embodiments of laser processing nozzles The contraction portion directly transitions to the expansion portion, and there is no straight section between the contraction portion and the expansion portion.

[0035] A connecting section is also provided at the nozzle inlet. The connecting section is a straight channel or a channel with a gradually contracting 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 section wall 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 comprises the above-mentioned laser processing nozzle. Specifically, the laser processing equipment is equipped with a laser cutting processing head, and the laser processing nozzle is installed on the processing head. The laser processing equipment also comprises a laser connected to the laser cutting processing head. The technical features of the above embodiments may be combined arbitrarily. To make the description concise, 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, they should be considered to be within the scope of this specification.

[0038] The above embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent application. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached 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 cross-sectional area of ​​the throat portion is S1, the cross-sectional area at the outlet of the expansion portion is S2, and S1 and S2 have the following functional relationship: S2≤k*(-0.0171*S1 2 +1.3802*S1-0.8931) Where k is the correction factor, 1.147 <k<1.318。 2. The laser processing nozzle according to claim 1, characterized in that: The value range of k is 1.147 <k<1.217。 3. The laser processing nozzle according to claim 1, characterized in that: The value range of S1 is 3~20mm 2 .

4. The laser processing nozzle according to claim 1, characterized in that: An average inclination angle of the inner wall surface of the expansion portion relative to the longitudinal axis of the channel is greater than 0.5° and less than 10°.

5. The laser processing nozzle according to claim 4, characterized in that: An average inclination angle of the inner wall surface of the expansion portion relative to the longitudinal axis of the channel is greater than 2° and less than 5°.

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 0.50~0.

78.

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 contracting 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 section 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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