Air nozzle and air blowing method suitable for laser processing of holes with large depth-to-diameter ratio

Abstract

The present invention belongs to the field of laser processing, and provides a gas nozzle and a blowing method suitable for laser processing of large aspect ratio holes. The gas nozzle comprises: a gas nozzle body, a small depth blowing module, a medium depth blowing module and a large depth blowing module. The gas nozzle body is a hollow conical structure; the small depth blowing module is installed at the lower part of the gas nozzle body, and is used to blow and remove slag from micropores with a small aspect ratio; the large depth blowing module comprises a flat glass, a third air inlet, and a third solenoid valve, so as to blow and remove slag from micropores with a large aspect ratio, and then according to the change of the aspect ratio during the micropore processing, a suitable blowing module is used for blowing, so that the residue inside the micropore is fully stirred by the airflow, and has a channel for discharging outward, so as to ensure smooth discharge of the residue, reduce heat accumulation, and improve processing efficiency and quality.

Description

Technical Field

[0001] The invention belongs to the technical field of laser processing, and in particular relates to an air nozzle and an air blowing method suitable for laser processing of holes with a large aspect ratio. Background Art

[0002] In aircraft engine flame tubes, blades and other parts, there is a large demand for micro-hole processing on the parts for ventilation and cooling purposes. Currently, a rotary cutting scanning laser processing device is usually used to achieve micro-hole processing. This device mainly forms a spiral scan by rotating the light beam to achieve material removal in a specified area. It has the advantages of controllable processing taper and high processing accuracy.

[0003] However, when this method is used to process some micro-holes with a large aspect ratio, its processing efficiency is difficult to meet the index requirements, and a large recast layer is prone to appear in the deeper position of the micro-hole. The reason is that the insufficient processing capacity is closely related to the effect of blowing and deslagging of micro-holes with a large aspect ratio. At present, coaxial blowing is usually used for deslagging. In this mode, the diameter of the micro-hole is small, generally about φ0.5-1mm, and the air nozzle is usually designed with a simple conical structure. In order to ensure the depth of the processed hole and the air nozzle mouth does not block light, its outlet diameter is usually designed to be larger than the diameter of the processed micro-hole. Therefore, the airflow is often "pressed" above the micro-hole, especially when the processing depth increases, it is difficult to form airflow disturbance at the bottom of the micro-hole, so that the molten droplets and plasma in the hole cannot be quickly discharged, and these removals hinder the laser from continuing to propagate downward, and by absorbing laser energy, heat accumulation, ablation and severe recast layer are caused, resulting in low processing efficiency, poor processing quality and processing taper. Summary of the invention

[0004] The purpose of the present invention is to provide an air nozzle and an air blowing method suitable for laser processing of large aspect ratio holes, aiming to solve the technical problem that the air nozzle and the air blowing method suitable for laser processing in the prior art cannot effectively remove slag when processing large aspect ratio micro holes.

[0005] In a first aspect, the present invention provides a gas nozzle suitable for laser processing of holes with a large aspect ratio, comprising:

[0006] An air nozzle body, wherein the air nozzle body is a hollow conical structure;

[0007] A small depth blowing module, which is installed at the lower part of the air nozzle body and is used for blowing and deslagging micro-holes with a small aspect ratio;

[0008] A large-depth blowing module, the large-depth blowing module includes a flat glass, a third air inlet, and a third solenoid valve. The flat glass is placed inside the air nozzle body. A microchannel is provided at the center of the flat glass as an internal air outlet. The third air inlet is located on the cylinder wall of the air nozzle body. The third solenoid valve controls the air pressure of the large-depth blowing module to blow and deslagging micropores with a large aspect ratio.

[0009] In a second aspect, the present invention further provides a blowing method of the air nozzle as described in the first aspect, comprising:

[0010] During laser processing, different blowing modules are selected according to the actual depth-to-diameter ratio of the processed hole;

[0011] When the actual depth-to-diameter ratio of the processed hole is less than 4:1, the first solenoid valve is opened, and the small-depth blowing module is used to blow air into the processing area;

[0012] When the depth-to-diameter ratio of the processing reaches 3:1 to 7:1, the first solenoid valve is closed and the second solenoid valve is opened, and the medium-depth blowing module is used to blow air into the processing area;

[0013] When the actual depth-to-diameter ratio of the processed hole reaches greater than 6:1, the second solenoid valve is closed and the third solenoid valve is opened, and the processing area is blown using a large-depth blowing module, so that the airflow passes through the upper inner cavity of the air nozzle body and is ejected through the air outlet of the large-depth blowing module.

[0014] The present invention is suitable for the air nozzle of large aspect ratio hole laser processing, and comprises an air nozzle body, a small depth blowing module and a large depth blowing module. The air nozzle body is a hollow conical structure, and the small depth blowing module is installed at the lower part of the air nozzle body, and is used for blowing and deslagging micropores with small aspect ratio; the large depth blowing module comprises flat glass, a third air inlet, and a third solenoid valve. The flat glass is arranged inside the air nozzle body, and a micro-flow channel is arranged at the center of the flat glass as an internal air outlet. The third air inlet is located on the cylinder wall of the air nozzle body, and the third solenoid valve controls the air pressure of the large depth blowing module to blow and deslagging micropores with large aspect ratio; and then according to the processing aspect ratio, a suitable blowing module is used for blowing, so that the residue inside the micropore can be fully stirred by the airflow, and at the same time, there is a channel for outward discharge, so as to ensure smooth discharge of the residue, reduce heat accumulation, and finally achieve the purpose of improving processing efficiency and quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the structure of a gas nozzle suitable for laser processing of holes with a large aspect ratio provided by the first embodiment of the present invention is shown;

[0016] Figure 2 Schematic diagram of optimized airflow microchannel structure;

[0017] Figure 3 A flow chart of an air blowing method applicable to laser processing of holes with a large aspect ratio provided by the second embodiment of the present invention is shown;

[0018] Figure 4 The schematic diagram of the blowing in the first stage of laser processing of a hole with a large aspect ratio is shown;

[0019] Figure 5 A schematic diagram of air blowing in the second stage of laser processing of large aspect ratio holes is shown;

[0020] Figure 6 A schematic diagram of air blowing during the third stage of laser processing of large aspect ratio holes is shown.

[0021] Description of reference numerals:

[0022] 1-air nozzle body, 2-small depth blowing module, 3-medium depth blowing module, 4-large depth blowing module, 5-laser, 6-air nozzle outlet, 71-first air inlet, 73-third air inlet, 81-first solenoid valve, 82-second solenoid valve, 83-third solenoid valve, 9-airflow microchannel, 10-air outlet of airflow microchannel, 11-air inlet of airflow microchannel, 12-small hole for contraction of airflow microchannel, 13-microflow channel, 14-flat glass. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0024] The specific implementation of the present invention is described in detail below in conjunction with specific embodiments:

[0025] Embodiment 1:

[0026] Figure 1 The schematic diagram of the structure of the gas nozzle applicable to the laser processing of a hole with a large aspect ratio provided by the first embodiment of the present invention is shown. For the convenience of explanation, only the part related to the embodiment of the present invention is shown, which is described in detail as follows:

[0027] The gas nozzle suitable for laser processing of a hole with a large aspect ratio shown in the embodiment of the present invention comprises a gas nozzle body 1 , a small-depth blowing module 2 , a medium-depth blowing module 3 and a large-depth blowing module 4 .

[0028] By improving the single air nozzle of an ordinary air nozzle into one with three different blowing modules, namely, small depth blowing module 2, medium depth blowing module 3, and large depth blowing module 4, to respectively adapt to the blowing when the aspect ratio changes during the processing, the flexibility of the air nozzle in laser processing of large aspect ratio holes is greatly improved. According to the change of the aspect ratio of the processing, a suitable blowing module is used for blowing, so that the residue inside the micropores can be fully stirred by the airflow, and at the same time, there is a channel for outward discharge, which ensures that the residue is discharged smoothly, reduces heat accumulation, and ultimately achieves the purpose of improving processing efficiency and quality.

[0029] The nozzle body 1 is a hollow conical structure, carrying a blowing module suitable for different processing depths. The laser performs rotary cutting movement inside the nozzle body and passes through the center.

[0030] The small-depth blowing module 2 is located at the lower part of the air nozzle body 1, and its airflow delivery outlet is the air nozzle outlet 6 of the air nozzle body; the medium-depth blowing module 3 is installed in the middle part of the air nozzle body 1, and its airflow microchannel can be installed in the installation groove inside the cylinder wall or can be installed on the outside of the cylinder wall. The medium-depth blowing module 3 can blow a fine airflow obliquely into the processed micropores, and can form disturbances in the micropores through the sequential control of multiple airflow microchannel solenoid valves to facilitate slag removal and heat dissipation; the large-depth blowing module 5 includes a flat glass arranged in the center of the air nozzle body 1. The airflow enters the air nozzle body 1 through the large-depth blowing module 5, and blows the processing area in the hole through the microchannel 13 opened in the flat glass 14.

[0031] The small depth blowing module 2 is installed at the lower part of the air nozzle body 1, and is used for blowing and deslagging the micropores in the small aspect ratio stage. The small depth blowing module 2 includes an air nozzle outlet 6, a first air inlet 71, a connecting air pipe and a first solenoid valve 81 for controlling the air pressure switch. The first air inlet 71 is arranged at the lower part of the air nozzle body 1, and the connecting air pipe connects the first air inlet 71 to the air source (not shown). The first solenoid valve 81 is arranged between the first air inlet 71 and the air source to control the gas pressure and flow in the connecting air pipe. The diameter of the air nozzle outlet 6 is determined according to the beam scanning size and the inclination angle, and is usually 0.8-2mm. Preferably, the diameter of the air nozzle outlet 6 is 1.5mm.

[0032] The medium-depth blowing module 3 is installed in the middle of the nozzle body 1, and is used to blow and remove slag from the micropores entering the medium-depth-diameter ratio stage. The medium-depth blowing module 2 includes an airflow microchannel 9, a connecting air pipe and a second solenoid valve 82, and the second solenoid valve 82 is used to control the air pressure and flow of the airflow microchannel 9. The number of airflow microchannels 9 is 3 or more, and the airflow microchannels 9 can be evenly distributed in the mounting groove of the cylinder wall of the nozzle body 1 or distributed on the outer side of the cylinder wall of the nozzle body 1. The horizontal position of the air outlet 10 of the airflow microchannel 9 is flush with or slightly exceeds the bottom end face of the nozzle body 1, and the air inlet 11 of the airflow microchannel 9 is connected to the air source (not shown) through the connecting air pipe, and the second solenoid valve 82 is arranged between the connecting air pipe and the air source. The inclination angle of the airflow microchannel 9 is 0.04rad-0.08rad, and points to the central axis of the nozzle, and its outlet diameter can be 0.3-0.8mm. Preferably, the inclination angle of the airflow microchannel 9 is 0.062rad.

[0033] The air flow microchannel 9 can adopt a more optimal structural form. Figure 2 Schematic diagram of optimized airflow microchannel structure, Figure 2 As shown, the inlet section (including the air inlet 11) and the outlet section (including the air outlet 10) of the air flow microchannel 9 are cylindrical holes, and the middle section of the air flow microchannel gradually shrinks into a small hole 12, that is, a relative convex portion is formed in the middle section of the air flow microchannel 9, a contraction portion is formed in the inlet section, and an expansion portion is formed in the outlet section. The length of the small hole 12 is equal to the diameter of the small hole, and the length of the contraction portion is preferably equal to the cosine value of the contraction section semi-cone angle multiplied by the difference between the inlet radius of the air flow microchannel 9 and the radius of the small hole, and the length of the expansion portion is preferably equal to the cosine value of the contraction section semi-cone angle multiplied by the difference between the inlet radius of the air flow microchannel 9 and the radius of the small hole, wherein the semi-cone angle of the contraction portion is preferably 20° to 30°, and the semi-cone angle of the expansion portion is preferably 5° to 10°. When the deep blowing module 3 is used for blowing, after the air flow converges through the narrow small hole 12, its flow rate will increase sharply, forming a high-speed fine air flow, so that the air flow can penetrate into the bottom area of ​​the processing and enhance the ability of the air flow to carry out the residue.

[0034] The deep blowing module 4 is used to blow and remove slag from the micropores that have entered the large aspect ratio stage. The deep blowing module 4 includes a flat glass 14, a third air inlet 73, and a third solenoid valve 83. The flat glass 14 can be placed on the lower part of the nozzle body 1 by bonding or buckling, and a micro-channel 13 is arranged at the center thereof. The installation height of the flat glass 14 is set so that the light beam of the rotary cutting scan will not pass through the micro-channel 13. The third air inlet 73 is located on the cylinder wall of the nozzle body 1, and the third solenoid valve 83 controls the air pressure of the deep blowing module 4.

[0035] In the processing of micro-holes with a large aspect ratio, the thickness of the flat glass 14 is about 0.3-1mm and the diameter of the micro-hole is 0.2-0.6mm. The vertical distance between its fixed position and the air nozzle outlet 6 can be 3-8mm, so as to form two blowing modules for different depths inside the air nozzle. At this time, the laser can directly pass through the flat glass 14 and will not pass through the microfluidic channel of the flat glass 14, so it will not affect the light path transmission.

[0036] Preferably, the diameter of the micro-channel 13 is 0.3 mm, and it is located at the center of the flat glass 14 inside the nozzle body 1. The thickness of the flat glass 14 is 0.6 mm, and its fixed position is 5 mm vertically away from the nozzle outlet 6.

[0037] Embodiment 2:

[0038] Figure 3 The flowchart of the blowing method applicable to the laser processing of a hole with a large aspect ratio provided by the second embodiment of the present invention is shown. For the convenience of explanation, only the part related to the embodiment of the present invention is shown, including:

[0039] Step 31, during the laser processing, different blowing modules are selected according to the actual depth-to-diameter ratio change stage of the processed hole.

[0040] Step 32, when the actual depth-to-diameter ratio of the processed hole is less than 4:1, open the first solenoid valve and use the small-depth blowing module of the air nozzle to blow air to the processing area;

[0041] Step 33, when the actual depth-to-diameter ratio of the processed hole reaches the range of 3:1 to 7:1, close the first solenoid valve and open the second solenoid valve, and use the medium-depth blowing module to blow air into the processing area;

[0042] Step 34, when the depth-to-diameter ratio reaches greater than 6:1, switch to the large-depth blowing module, use the large-depth blowing module to blow air, so that the airflow passes through the upper inner cavity of the air nozzle body and is ejected through the air outlet of the large-depth blowing module.

[0043] According to the change of depth-to-diameter ratio during the machining process, different forms of air blowing and slag removal are carried out in three stages.

[0044] In the first stage, when the depth-to-diameter ratio is less than 4:1, a small-depth blowing module is used for blowing. The air source is ordinary compressed air with an air pressure of 0.3-0.6MPa. Although the airflow diameter is larger than the micropore diameter, due to the small depth, the airflow can reach the bottom of the micropore and form a vortex disturbance, which quickly drives the residue out of the hole and discharges it.

[0045] In the second stage, when the depth-to-diameter ratio is 3:1 to 7:1, due to the larger depth-to-diameter ratio, the upward discharge distance of the residue at the bottom of the hole becomes longer, and it is also suppressed by the upper airflow at the hole mouth, making it difficult to discharge the residue. At this time, the small-depth blowing module is closed and the medium-depth blowing module is turned on.

[0046] During the processing at this stage, the solenoid valves of the medium-depth blowing module can be controlled to close and open in sequence, so that the gas is ejected from each airflow microchannel in sequence. Preferably, the sequential switching direction of each solenoid valve is opposite to the rotary scanning direction of the light beam. Since the channel diameter is smaller than the micropore diameter, the airflow can be blown obliquely into the micropore, and at the same time, a rotational motion is formed in the hole to enhance the airflow disturbance and drive the residue out. The gas source at this stage can be argon or oxygen, and the air pressure can be 0.4-0.6MPa. The relative molecular mass of argon is 40, which is greater than the relative molecular mass of air 29, which can enhance the gas stirring ability under small flow rates; when the workpiece material has a high content of active elements such as carbon and iron, oxygen can be used to assist in blowing and deslagging, which helps the residue to gasify or oxidize into smaller droplets, making it easier to be carried away by the airflow.

[0047] In the third stage, when the depth-to-diameter ratio is greater than 6:1, the airflow of the medium-depth blowing module is gradually blocked by the hole wall and cannot be blown into the bottom of the hole. At this time, the medium-depth blowing module is closed and the large-depth blowing module is opened.

[0048] By opening the third solenoid valve, the airflow passes through the upper inner cavity and is ejected through the micro-flow channel in the flat glass, the diameter of which is smaller than the diameter of the micro-pores, so that the airflow can be directly blown into the micro-pores and leave a slag discharge space to take away the residue. The gas source can be argon or oxygen, and the gas pressure can be 0.4-0.6MPa.

[0049] Optionally, when a rotary cutting scanning device is used to process a micro hole with a diameter of 0.8 mm, the material thickness is 8 mm. The blowing method suitable for rotary cutting scanning laser processing will be divided into three stages according to the processing depth or depth-to-diameter ratio, and different forms of blowing and slag removal will be performed.

[0050] In the first stage, when the processing depth is less than 3mm, such as Figure 4 As shown, a small depth blowing module 2 is used for blowing, the air source is ordinary compressed air, the air pressure is 0.4 MPa, and the air flow diameter is 1.5 mm, which is larger than the micropore diameter. However, due to the small depth, the air flow can reach the bottom of the micropore and form a vortex disturbance, which quickly drives the residue out of the hole and discharges it.

[0051] In the second stage, when the processing depth is 3-6mm, Figure 5As shown, due to the large depth-to-diameter ratio, the upward discharge distance of the residue at the bottom of the hole becomes longer, and it is also suppressed by the upper airflow at the hole mouth, making it difficult to discharge the residue. At this time, the small-depth blowing module 2 is closed and the medium-depth blowing module 3 is opened.

[0052] The gas is ejected from the air flow microchannel in sequence. Since the channel diameter is smaller than the micropore diameter, the gas flow is blown obliquely into the micropore. At the same time, the solenoid valve is controlled to close and open in sequence, so that a rotation disturbance is formed in the pore, thereby driving the residue to be discharged. The gas source is argon gas with a pressure of 0.4MPa.

[0053] In the third stage, when the processing depth is 6-8mm, as the processing depth increases, the airflow of the medium-depth blowing module is blocked by the hole wall and cannot blow into the bottom of the hole. Figure 6 As shown, the medium-depth blowing module is closed, and the large-depth blowing module 4 is opened, and this method is used until the micropores are punched.

[0054] By opening the electromagnetic valve, the air flow passes through the upper inner cavity and sprays out through the central air hole of the flat glass. The air flow blows directly into the micropores to take away the residue. The gas source uses argon gas with a pressure of 0.5MPa.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A laser processed air nozzle, characterized in that: The gas nozzle comprises: An air nozzle body, wherein the air nozzle body is a hollow conical structure; A small depth blowing module, which is arranged at the lower part of the air nozzle body and is used for blowing and deslagging micropores with a small aspect ratio; the small depth blowing module comprises an air nozzle outlet, a first air inlet and a first solenoid valve, the first air inlet is arranged at the lower part of the air nozzle body, the first solenoid valve is arranged between the first air inlet and the air source, and is used for controlling the gas flow rate flowing into the first air inlet; A medium-depth blowing module, the medium-depth blowing module comprising an airflow microchannel, a connecting air pipe and a second solenoid valve, the airflow microchannel is connected to the connecting air pipe, and the second solenoid valve is used to control the air pressure and flow rate of the gas flowing into the airflow microchannel; A large-depth blowing module, the large-depth blowing module comprises a flat glass, a third air inlet, and a third solenoid valve. The flat glass is arranged at the lower part of the nozzle body. A micro-channel is arranged at the center of the flat glass as an internal air outlet. The third air inlet is located on the cylinder wall of the nozzle body. The third solenoid valve controls the air pressure of the large-depth blowing module to blow and deslagging the micro-pores with a large aspect ratio. The flat glass of the deep-depth blowing module is placed inside the air nozzle body by bonding or buckling, and the installation height of the flat glass is set so that the light beam of the rotary cutting scan will not pass through the micro-fluidic channel.

2. The gas nozzle according to claim 1, characterized in that: The number of the airflow microchannels is at least 3, and the airflow microchannels are evenly distributed in the mounting groove of the cylinder wall of the air nozzle body or distributed on the outer side of the cylinder wall of the air nozzle body.

3. The gas nozzle according to claim 2, characterized in that: The airflow microchannel is evenly distributed in the wall of the air nozzle body, with an inclination angle of 0.04rad-0.08rad, pointing to the central axis of the air nozzle, and an outlet diameter of 0.3mm-0.8mm; the inlet section and outlet section of the airflow microchannel are cylindrical holes, which gradually shrink into small holes in the middle section of the airflow microchannel, and the length of the small hole is equal to the diameter, forming a contraction portion in the inlet section and an expansion portion in the outlet section.

4. The gas nozzle according to claim 3, characterized in that: The semi-cone angle of the contraction portion is set to 20 degrees to 30 degrees, and the semi-cone angle of the expansion portion is set to 5 degrees to 10 degrees.

5. The gas nozzle according to claim 1, characterized in that: The air outlet of the air flow microchannel is located at the bottom end surface of the air nozzle body, and the air inlet of the air flow microchannel receives the inflow of gas through the connecting air pipe.

6. A blowing method for an air nozzle as claimed in any one of claims 1 to 5, characterized in that: The method comprises: During the laser processing, different air blowing modules are selected according to the actual depth-to-diameter ratio of the processed hole, and different forms of air blowing and slag removal are performed in three stages; In the first stage, when the actual depth of the processed hole is less than 3 mm, the first solenoid valve is opened and the small-depth blowing module is used to blow air into the processing area; In the second stage, when the actual depth of the processed hole reaches 3 mm and is less than 6 mm, the first solenoid valve is closed and the second solenoid valve is opened, and the medium-depth blowing module is used to blow air into the processing area; In the third stage, when the actual processing hole depth reaches 6-8mm, as the processing depth increases, the airflow of the medium-depth blowing module is blocked by the hole wall and cannot be blown into the bottom of the hole. At this time, the medium-depth blowing module is closed and the large-depth blowing module is turned on. This method is used until the micropores are punched.

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