Apparatus and method for online measurement of water guide laser waterjet

Abstract

The application discloses a device and method for measuring water guide laser water jet on line, the method comprising: obtaining laser data of a laser unit and water jet data of a water jet unit; processing data of a workpiece of a mechanical unit based on the laser data and the water jet data to obtain a data processing result; detecting a voltage value between a metal structure part of the water jet unit and the workpiece of the mechanical unit based on the data processing result to determine a water jet state according to the detected voltage value. The measuring method can be used without adding complex and expensive equipment, and the overall structure does not need to be greatly adjusted, and meanwhile, the measuring method can realize on-line measurement of the depth and further measurement of the processing state of the workpiece.

Description

Technical Field

[0001] This invention relates to the field of water-guided laser processing technology, and in particular to equipment and methods for online measurement of water-guided laser water jets. Background Technology

[0002] Water jet guided laser (VLS) is a special processing technology that combines water jet and laser. In VLS, the laser beam is first focused onto a micro-jet of water. Due to the difference in refractive index between water and air, the laser undergoes total internal reflection at the water-air interface, allowing it to propagate forward. The water jet guides the laser beam to the material surface for processing. VLS combines the advantages of conventional laser processing and water jet processing. On one hand, it inherits the advantages of laser cutting, such as no mechanical pressure, no tool wear, and narrow kerf width. On the other hand, it utilizes the excellent heat dissipation and scouring effect of the micro-jet to effectively reduce thermal effects near the cutting area, promptly remove molten slag to prevent contamination and remelting, greatly improving cutting quality and effectively solving the drawbacks of traditional machining and conventional laser processing.

[0003] In water-guided laser technology, laser energy needs to be guided to the workpiece surface by a fine water jet for processing. Therefore, obtaining a stable and fine water jet is a prerequisite for realizing water-guided laser technology. The stability and surface shape of the water jet directly determine whether the water jet can successfully guide the laser, while the stable length of the water jet directly affects the processing distance of the water-guided laser. In actual use, the water jet can only remain stable within a certain length range, i.e., in a laminar flow state. Once this length is exceeded, the liquid becomes unstable and eventually atomizes. When the water jet is unstable, the laser cannot undergo total internal reflection within it, limiting the processing length.

[0004] The waterjet length represents the maximum distance that can be maintained between the machining head and the workpiece, and it also affects machining efficiency. On the other hand, the waterjet length also reflects the state of the machining system, such as nozzle wear. During machining, the waterjet length is one of the characteristics of the machining progress; measuring the waterjet length can provide information about the actual machining situation. In existing technologies, the secondary radiation of the laser beam in the liquid jet is detected and converted into a detection signal. However, this cannot be used during machining because reflected light at the machining site affects the measurement results; furthermore, the detection unit itself is difficult to move and can only measure in a fixed position. Existing technologies use electromagnetic radiation or sound waves for measurement, which requires complex and expensive equipment, and its feasibility remains questionable. Sound waves are essentially vibrations of a medium, and for water jets, vibration can cause the water jet to be disturbed and broken; at the same time, sound waves are difficult to focus on the small diameter of a water jet. Electromagnetic radiation is also questionable due to the difficulty of its installation location (because it overlaps with the laser beam path). Another approach is to place the measuring device next to the machining head, repeatedly moving the workpiece under the measuring device and then under the water jet during machining. This method cannot achieve real-time measurement and consumes more time. Summary of the Invention

[0005] The present invention aims to at least partially solve one of the technical problems in the related art.

[0006] Therefore, this invention proposes a device for online measurement of water-guided laser water jets, which can effectively realize online detection of water jet state and water jet length.

[0007] Another object of the present invention is to provide a method for online measurement of water-guided laser water jets.

[0008] To achieve the above objectives, the present invention provides a device for online measurement of water-guided laser water jets, comprising:

[0009] The laser unit is used to provide laser light to the equipment;

[0010] A jetting unit for providing a water jet to a device, the jetting unit comprising at least a metal structural portion that contacts a water cavity;

[0011] Mechanical unit, including processed parts;

[0012] The detection unit is used to detect the electrical signal between the metal structure of the jet unit and the processed part of the mechanical unit, so as to determine the water jet state based on the detected change value of the electrical signal.

[0013] In addition, the device for online measurement of water-guided laser water jets according to the above embodiments of the present invention may also have the following additional technical features:

[0014] Furthermore, in one embodiment of the present invention, when the water jet is in a stable state, it is considered as a conductor of fixed width, and the resistance value of the conductor is:

[0015]

[0016] Where ρ is the resistivity of water, l is the length of the water jet, and S is the cross-sectional area of ​​the water jet.

[0017] Furthermore, in one embodiment of the present invention, the resistance value of the conductor includes the series resistance of the water jet unit resistor, the water jet resistor, and the mechanical unit resistor.

[0018] Furthermore, in one embodiment of the present invention, when the water jet is in the stable state, the resistance value is obtained as a linear change based on the length of the water jet.

[0019] Furthermore, in one embodiment of the present invention, the jet unit includes a coupling unit.

[0020] The coupling unit moves up and down to obtain up and down movement data;

[0021] The detection unit detects the change value of the electrical signal based on the up-and-down movement data, and then obtains the maximum value of the water jet length in a stable state based on the change value of the electrical signal.

[0022] Furthermore, in one embodiment of the present invention, while the mechanical unit moves along three preset axes to process the workpiece, the detection unit detects the real-time water jet length and determines whether the water jet is interrupted based on the resistance value.

[0023] To achieve the above objectives, another aspect of the present invention provides a method for online measurement of water-guided laser water jets, comprising:

[0024] Acquire laser data from the laser unit and water jet data from the jet unit;

[0025] The data processing results are obtained by performing data processing on the workpiece of the mechanical unit based on the laser data and water jet data;

[0026] Based on the data processing results, the voltage value between the metal structure of the jet unit and the processed parts of the mechanical unit is detected, so as to determine the water jet state according to the magnitude of the detected voltage value.

[0027] The device and method for online measurement of water-guided laser water jets according to embodiments of the present invention enable online detection of water jet state and water jet length.

[0028] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0029] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0030] Figure 1 This is a schematic diagram of a device for online measurement of water-guided laser water jets according to an embodiment of the present invention;

[0031] Figure 2 This is a schematic diagram of another device for online measurement of water-guided laser water jets according to an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram illustrating the trend of detection signal changes according to an embodiment of the present invention;

[0033] Figure 4 This is a schematic diagram of another device for online measurement of water-guided laser water jets according to an embodiment of the present invention;

[0034] Figure 5 This is a flowchart of a method for online measurement of water-guided laser water jets according to an embodiment of the present invention. Detailed Implementation

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0037] The apparatus and method for online measurement of water-guided laser water jets according to embodiments of the present invention are described below with reference to the accompanying drawings.

[0038] Figure 1 This is a schematic diagram of the structure of a device for online measurement of water-guided laser water jets according to an embodiment of the present invention.

[0039] like Figure 1 As shown, the device for online measurement of water-guided laser water jets includes:

[0040] Laser unit 100 is used to provide laser light to the device;

[0041] The jet unit 200 is used to provide a water jet to the device. The jet unit includes at least a metal structural part that is in contact with the water cavity.

[0042] Mechanical unit 300 includes machined parts;

[0043] The detection unit 400 is used to detect the electrical signal between the metal structure of the jet unit 200 and the processed part of the mechanical unit 300, so as to determine the water jet state based on the detected change value of the electrical signal.

[0044] Specifically, the laser unit 100 provides laser light to the equipment; the jet unit 200 provides water jet to the equipment, at least part of which is a metal structure and in contact with the water cavity; the mechanical unit 300 can be an actual workpiece or a fixed detection surface; and the detection unit 400 determines the water jet status by applying voltage between the metal part of the jet unit 200 and the mechanical unit 300 and detecting the voltage and / or current.

[0045] In some embodiments of the present invention, when the water jet is in a steady state, it can be regarded as a conductor of fixed width with a resistance of:

[0046]

[0047] Where ρ is the resistivity of water, l is the length of the water jet, and S is the cross-sectional area of ​​the water jet.

[0048] In some embodiments of the present invention, the actual overall resistance is a series connection of the water jet unit resistor, the water jet resistor, and the mechanical unit resistor.

[0049] It is understandable that, since the cross-sectional area of ​​the water jet is much smaller than that of the water cavity in the jet unit, the resistance of the water in the jet unit is much smaller than that of the water jet; the other part of the jet unit is a large area of ​​metal, and its resistance can also be ignored; the same applies to the mechanical unit.

[0050] It is understandable that the resistance detected by the detection unit is basically the resistance of the water jet.

[0051] In some embodiments of the present invention, when the water jet is in the stable state, the resistance value is obtained as a linear change based on the length of the water jet.

[0052] Specifically, when the water jet is in a stable state, the resistance value changes linearly with the length of the water jet. Therefore, the detection unit can detect regular voltage and / or resistance values, thereby deducing the length of the water jet.

[0053] In some embodiments of the present invention, when the water jet is in an unstable state, its resistance value will fluctuate or even break due to the water flow no longer being in a stable state, thereby allowing detection of whether the water jet is in a stable state.

[0054] In some embodiments of the present invention Figure 2 This is a schematic diagram of a device connection for determining the length of a water jet, as shown in this invention.

[0055] It is understandable that the jet element can be a coupling element 201.

[0056] The coupling unit 201 moves up and down to obtain up and down movement data;

[0057] The detection unit 300 detects the change value of the electrical signal based on the up and down movement data, and then obtains the maximum value of the water jet length in a steady state based on the change value of the electrical signal.

[0058] Specifically, the coupling unit 201 moves up and down, and the detection unit 400 detects the changes in the electrical signal to determine the stable maximum length.

[0059] Furthermore, the trend of its detection signal variation with distance is as follows: Figure 3 As shown, in Figure 3 In part ①, the voltage is in a stable phase, and the detected voltage increases with the distance it moves downward; then the water jet breaks up, and the voltage rises to the power supply voltage.

[0060] In some embodiments of the present invention Figure 3 This is a schematic diagram illustrating the connection of an online monitoring device during processing, as shown in the present invention. Figure 3 As shown, the mechanical unit 300 moves along three axes. While the water-guided laser is processing, the detection unit 400 detects the length of the water jet and determines whether the jet is interrupted by the resistance value, thereby determining the processing loading and processing depth.

[0061] The device for online measurement of water-guided laser water jets according to embodiments of the present invention enables online detection of water jet state and water jet length. Furthermore, the measurement method employed by the present invention does not require the addition of complex and expensive equipment, does not require significant adjustments to the overall structure, and can simultaneously achieve online depth measurement, thereby measuring the processing status of the workpiece.

[0062] To achieve the above embodiments, such as Figure 4 As shown, this embodiment also provides a method for online measurement of water-guided laser water jets, including:

[0063] S1, acquire laser data from the laser unit and water jet data from the jet unit;

[0064] S2, based on laser data and water jet data, performs data processing on the workpiece of the mechanical unit to obtain data processing results;

[0065] S3, based on the data processing results, detects the voltage value between the metal structure of the jet unit and the processed parts of the mechanical unit, so as to determine the water jet state according to the magnitude of the detected voltage value.

[0066] Furthermore, when the water jet is in a stable state, it is considered as a conductor of fixed width, and the resistance value of the conductor is:

[0067]

[0068] Where ρ is the resistivity of water, l is the length of the water jet, and S is the cross-sectional area of ​​the water jet.

[0069] Furthermore, the resistance value of the conductor includes the series resistance of the water jet unit resistance, the water jet resistance, and the mechanical unit resistance.

[0070] Furthermore, when the water jet is in the stable state, the resistance value is obtained as a linear change based on the length of the water jet.

[0071] The method for online measurement of water-guided laser water jets according to embodiments of the present invention enables online detection of water jet state and water jet length. Furthermore, the measurement method employed by the present invention does not require the addition of complex and expensive equipment, does not require significant adjustments to the overall structure, and can simultaneously achieve online depth measurement, thereby measuring the processing status of the workpiece.

[0072] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0073] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

Claims

1. A device for online measurement of water-guided laser water jets, characterized in that, include: The laser unit is used to provide laser light to the equipment; A jetting unit for providing a water jet to a device, the jetting unit comprising at least a metal structural portion that contacts a water cavity; Mechanical unit, including processed parts; The detection unit is used to detect the resistance value between the metal structure part of the jet unit and the processed part of the mechanical unit, so as to determine the water jet state based on the detected change in resistance value. When the water jet is in a stable state, it is considered as a conductor of fixed width. The resistance value of the conductor includes the series resistance of the water jet unit resistance, the water jet resistance, and the mechanical unit resistance. While the mechanical unit moves along three preset axes to process the workpiece, the detection unit detects the real-time water jet length and determines whether the water jet is interrupted based on the resistance value.

2. The device according to claim 1, characterized in that, The resistance value of the conductor is: Where ρ is the resistivity of water, l is the length of the water jet, and S is the cross-sectional area of ​​the water jet.

3. The device according to claim 2, characterized in that, When the water jet is in the stable state, the resistance value is obtained as a linear change based on the length of the water jet.

4. The device according to claim 1, characterized in that, The jet unit includes a coupling unit. The coupling unit moves up and down to obtain up and down movement data; The detection unit detects the change in resistance value based on the up-and-down movement data, and then uses the change in resistance value to determine the maximum value of the water jet length in a stable state.

5. A method for online measurement of water-guided laser water jets, characterized in that, include: Acquire laser data from the laser unit and water jet data from the jet unit; The data processing results are obtained by performing data processing on the workpiece of the mechanical unit based on the laser data and water jet data; Based on the data processing results, the resistance value between the metal structure of the jet unit and the processed parts of the mechanical unit is detected, so as to determine the water jet state according to the detected resistance value. When the water jet is in a stable state, it is considered as a conductor of fixed width. The resistance value of the conductor includes the series resistance of the water jet unit resistance, the water jet resistance, and the mechanical unit resistance. While the mechanical unit moves along three preset axes to process the workpiece, the detection unit detects the real-time water jet length and determines whether the water jet is interrupted based on the resistance value.

6. The method according to claim 5, characterized in that, The resistance value of the conductor is: Where ρ is the resistivity of water, l is the length of the water jet, and S is the cross-sectional area of ​​the water jet.

7. The method according to claim 5, characterized in that, When the water jet is in a stable state, the resistance value is obtained as a linear change based on the length of the water jet.

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