Water beam guide laser processing technology and method for optimizing deslagging channel

Abstract

The invention provides a water beam guided laser processing technology and method for optimizing a deslagging channel, and the method for processing a workpiece through water beam guided laser comprises the following steps: on the basis of a front optimization design downward deslagging channel or a preferable processing direction, utilizing the efficient characteristics of preferable continuous wave (CW-M) laser, quasi-continuous wave (QCW) laser or other laser with relatively long pulse width, the method for improving the water beam guided laser processing efficiency is achieved. In the water beam guided laser machining process, based on optimized design of a deslagging channel and optimization of lasers with long pulse width parameters, the constraint that the upward discharging efficiency of residues is very limited in the traditional water beam guided laser machining process is broken through, the machining efficiency is greatly improved, and high-efficiency, low-heat-damage, high-precision and thick plate machining is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of laser precision machining, and particularly to a water-guided laser machining method and process. Background Art

[0002] Currently, laser machining has been widely applied to conventional industrial machining and micro-machining fields. Commonly used ones include continuous laser machining, long / short pulse laser machining (a pulse width greater than 1 ms is a long pulse, and a pulse width in the range of 1 ns and 1 ms is a short pulse), and ultra-short pulse (pulse width in the ps and fs order of magnitude) laser machining. In the machining areas of continuous laser machining, long / short pulse lasers, there will inevitably be a heat-affected zone and a recast layer, greatly reducing the machining quality and affecting the subsequent applications of the machined area. Traditional CW-M lasers or lasers with longer pulse widths are prone to heat accumulation in precision machining, resulting in material deformation or oxidation. Although a single QCW laser can reduce the heat effect, its machining efficiency for high-reflectivity materials (such as copper and aluminum) is insufficient. In the existing water-jet-guided laser machining technology, the mainstream is to guide a nanosecond pulsed laser beam into a water stream to form a water jet to guide the laser beam, thereby suppressing the accumulation of thermal effects generated during laser machining and reducing thermal damage; during the machining process, energy is mostly released in the form of explosive vaporization in an extremely short time, forming plasma and shock waves, and the material is extruded upward through the water jet and discharged, resulting in only a material removal of the order of 10 - 30 μm each time, leading to low machining efficiency, especially during the machining of thick materials. This makes it impossible to use large pulse-width lasers because too much residue cannot be discharged, and such lasers cannot be used in the development of water-jet-guided laser processes. How to improve the efficient slag discharge is the fundamental guarantee for the machining efficiency of water-jet-guided lasers. The present invention designs a slag discharge channel to preferentially discharge the residue downward, and combines the more efficient characteristics of continuous laser (CW-M), QCW laser (pulse width in the microsecond or millisecond level), or longer pulse-width laser compared to nanosecond laser machining to achieve efficient residue discharge, improve the machining efficiency, and break through the limitation that although water-jet-guided lasers have the characteristic of machining large-thickness plates, they are also extremely prone to reaching saturation in the machining thickness value and being restricted; in addition, for high-reflectivity metals (such as copper and aluminum), the thermal effect during machining reduces the reflectivity and improves the absorption efficiency of the material to achieve high-efficiency machining. Summary of the Invention

[0003] The purpose of the present invention is to provide a water-guided laser machining method and process to solve the problems existing in the above-mentioned prior art and achieve efficient water-guided laser machining.

[0004] To achieve the above purpose, the present invention provides the following solutions: The present invention provides a water beam-guided laser processing technology and method for optimizing the slag discharge channel. Based on the optimized design of the front-downward slag discharge channel or the preferred processing direction, the high-efficiency characteristics of the preferred continuous wave (CW-M) laser, quasi-continuous wave (QCW) laser, or longer pulse-width laser are utilized to achieve a method for improving the water beam-guided laser processing efficiency.

[0005] Preferably, the front-downward slag discharge channel is optimized in the following two ways, but not limited to these two ways. The first way is to optimize the design of the front-downward slag discharge channel; the second way is to preferentially select the workpiece processing direction to improve the slag discharge speed during the processing.

[0006] Preferably, based on the optimized design of the slag discharge channel, the residue during the laser processing is not limited by the very limited slag discharge amount caused by the upward discharge of the residue in the existing water-guided laser processing. The high-efficiency characteristics of the preferred continuous wave (CW-M) laser, quasi-continuous wave (QCW) laser, or longer pulse-width laser are utilized to achieve a high-efficiency processing method for efficiently generating residue and effectively discharging it. The preferred laser wavelengths are 1064nm / 532nm / 355nm, the pulse width range is 20ns–50ms, the frequency range is 100Hz–80kHz, and the peak power range is 1-20kW; Preferably, the first way is to design a front-downward slag discharge channel. Before the water beam-guided laser processes the workpiece, a through hole or channel is prefabricated in the workpiece processing path by mechanical processing, electrical discharge machining, or laser processing. This channel is used to guide the processing residue and residual water during the processing to quickly discharge downward along the prefabricated channel, preventing the accumulation effect of the melt and liquid flow from damaging the stable transmission of the water beam optical fiber and the effective conduction of the laser beam, and improving the processing efficiency.

[0007] Preferably, the first way is to design a front-downward slag discharge channel. For thick plate grooving, starting from the 5mm width direction at the edge of the scanning path, scan radially (perpendicular to the workpiece surface) multiple times or once to preferentially cut through, and then continue to feed the scanning path by 5mm. Repeat the above process until the entire path scanning is completed, forming a fast slag discharge channel in the processing path first, so as to improve the discharge speed of the molten slag and deposited liquid flow during the water beam-guided laser processing and improve the processing efficiency.

[0008] Preferably, the second way is to preferentially select the workpiece processing direction, including placing the workpiece obliquely, changing the small thickness direction of the workpiece cutting to the laser scanning direction, or flipping the workpiece 180 degrees after processing half of the thickness to process the other half of the depth, and increasing the slag discharge by rotating the axisymmetric processing of rotating parts.

[0009] Preferably, the workpiece is set at an inclined angle to utilize the gravity effect to achieve the smooth acceleration and discharge of the melt and liquid flow during the water beam-guided laser processing, improve the continuous reliability of the water beam optical fiber entering the material interior and the stable effectiveness of the transmitted laser, and improve the processing efficiency.

[0010] Preferably, through the preferred workpiece scanning strategy, the long (width) section of the workpiece is replaced with a short (narrow) section for cutting, or after machining half of the thickness, it is flipped 180 degrees to machine the other half of the depth, shortening the slag discharge channel and improving the efficiency of water-jet-guided laser material processing.

[0011] Preferably, during the machining process of the axisymmetric surface of a rotary part, the preferred part rotation and feeding method is adopted to achieve rapid slag discharge and residual aqueous solution, improving the machining efficiency.

[0012] The present invention has achieved the following technical effects compared with the prior art: The water-jet-guided laser process method provided by the present invention will optimize the design of the front downward slag discharge channel and the preferred laser processing direction, combine the high-efficiency characteristics of the preferred continuous wave (CW-M) laser, quasi-continuous wave (QCW) laser or longer pulse width laser, and improve the efficiency based on the optimized design of the slag discharge channel and the preferred relatively long laser action time. It can greatly enhance the impact slag discharge effect of the water beam, overcome the limitation of the extremely low slag discharge efficiency caused by the upward slag discharge from the periphery of the water beam in traditional water-jet-guided nanosecond lasers, greatly improve the machining efficiency, and can achieve the machining of thick materials and the high-efficiency, low heat damage, and high-precision machining of thin materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order 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 in the embodiments. 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.

[0014] Figure 1 It is a schematic diagram of the structure principle and slag removal of water-jet-guided laser machining in the present invention; Figure 2 It is a schematic diagram of the front prefabricated slag discharge channel method in the present invention; Figure 3 For Figure 2 A schematic diagram of making a small hole as a slag discharge channel for a larger hole in Figure 4 It is a schematic diagram of the front water-jet-guided laser machining process method in the present invention; Figure 5 It is a schematic diagram of the workpiece tilting method in the present invention; Figure 6 It is a schematic diagram of the scanning plane direction of the material processing cross-section in the present invention; Figure 7 It is a schematic diagram of the material processing cross-section flipping method in the present invention; Figure 8 It is a schematic diagram of the rotation and feeding in the present invention; In the figure: 1. Laser beam, 2. Focusing lens, 3. Optical window, 4. High-pressure deionized water, 5. Coupling cavity, 6. Thin liquid layer, 7. Nozzle, 8. Auxiliary gas, 9. Micro water jet, 10. Workpiece, 11. Slag, 12. Air gap, 13. Front pre-hole / slot slag discharge channel, 14. Large hole / slot to be machined. Detailed implementation mode

[0015] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0016] The purpose of the present invention is to provide a water-guided laser processing technology method to solve the problems existing in the prior art and achieve efficient water-guided laser processing.

[0017] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific implementation modes.

[0018] As Figures 1-8 shown, this embodiment provides a water-guided laser processing technology method. The workpiece is clamped and fixed on the table and positioned. The workbench is run to a suitable processing position; the laser generator is started to emit a laser beam. The laser beam is transmitted through the beam transformation cavity at the laser head and then focused and transmitted. The laser beam passes through the thin water layer of the liquid layer cavity and is focused to reach the nozzle. The laser beam enters the water beam optical fiber formed by the nozzle under the condition of total reflection and is conducted to reach the surface of the workpiece; the workbench drives the workpiece to perform planar two-dimensional movement or spatial three-dimensional movement under the control of the processing program, and cooperates with the laser beam to complete the cutting processing of the workpiece. The high temperature of the laser beam softens the surface material of the workpiece, and at the same time the water beam cools the processing area to reduce thermal damage.

[0019] In the present invention, through the slag discharge implementation schemes 1 to 4 designed and prefabricated in this patent, as shown in Figures 2-5 respectively; by designing the slag discharge channel, the residual slag is preferentially discharged downward, and combined with the characteristics that continuous laser (CW-M), QCW laser (pulse width in microseconds or milliseconds) or longer pulse width laser is more efficient than nanosecond laser processing, through the impact effect of the water beam optical fiber, the efficient discharge of the residual slag is realized, and the processing efficiency is improved. It breaks through the technical bottleneck in the existing water beam-guided laser processing technology that although it has the characteristic of processing large-thickness plates, it is also extremely easy to cause the processing thickness value to reach saturation and be limited.

[0020] During processing, the laser can be CW-M laser, QCW laser or laser with a longer pulse width, which is determined according to the thickness and characteristics of the processed material; the wavelength range of the laser can extend from the ultraviolet band to the near-infrared band, not limited to a specific value, and the specific selection is determined according to the physical properties of the workpiece; its output pulse width can range from 200 ns in the pulse width range to 50 ms, which is determined according to the actual processing requirements, but not limited to a specific value; its repetition frequency is determined according to the actual processing requirements, and the frequency range can range from 100 Hz to 80 kHz, but not limited to a specific value; the laser input peak power range can range from 1 kW to 20 kW.

[0021] Specifically, referring to Figure 2 In the embodiment of the pre-designed downward slag discharge channel in Method 1, before the water beam-guided laser processes the workpiece, a through hole or channel is prefabricated in the workpiece processing path by mechanical processing, electrical discharge machining or laser processing. This channel is used to guide the machining residues and residual water in the processing process to quickly drain downward along the prefabricated channel, preventing the accumulation effect of the melt and liquid flow from damaging the stable transmission of the water beam optical fiber and the effective conduction of the laser beam, and improving the processing efficiency.

[0022] In this embodiment, there is another implementation method, such as Figure 3 , when machining a slightly larger hole, a through hole can be prefabricated in the middle of the hole by mechanical processing, electrical discharge machining or laser processing as the slag discharge channel.

[0023] As another implementation method of the pre-designed slag discharge channel in Method 1 of this embodiment, referring to Figure 4 , for thick plate grooving, scan multiple times or once in the radial direction (perpendicular to the workpiece surface direction) from the 5 mm width direction at the edge of the scan path to preferentially cut through, and then continue to feed the scan path by 5 mm, repeating the above process until the entire path scan is completed, forming a fast slag discharge channel in the processing path first, so as to improve the discharge speed of the molten slag and deposited liquid flow during the water beam-guided laser processing, and improve the processing efficiency. Those skilled in the art can design it according to actual needs.

[0024] Referring to Figure 5 In the embodiment of Method 2 that optimizes the workpiece processing direction, the workpiece is set at an inclined angle, and by means of the gravity effect, the smooth discharge of the melt and liquid flow during the water beam-guided laser processing is realized, improving the continuous reliability of the water beam optical fiber entering the material and the stable effectiveness of the transmitted laser, and improving the processing efficiency.

[0025] In the embodiment of Method 2 that optimizes the workpiece processing direction, referring to Figure 6 , by optimizing the workpiece scanning strategy, the long (width) section of the workpiece is changed to a short (narrow) section for cutting, shortening the slag discharge channel and improving the efficiency of the water beam-guided laser processing of the material.

[0026] In the embodiment of the second method for optimizing the workpiece processing direction, referring to Figure 7 , which is another embodiment. The thick material is processed to half of its depth, then flipped to process the other side. The processing depth is reduced by half, the slag discharge channel is shortened, the difficulty of slag discharge is reduced, and the processing efficiency is improved.

[0027] In the embodiment of the second method for optimizing the workpiece processing direction, referring to Figure 8 , which is another embodiment. During the processing of the axisymmetric surface of a rotating part, the preferred part rotation and feeding method is adopted to quickly remove molten slag and residual aqueous solution, improving the processing efficiency.

[0028] In the present invention, in the designed slag discharge scheme, combined with the processing path such as Figures 6-8 , through the way of laser scanning, reciprocating feeding and scanning processing are carried out at the position to be processed, so as to perform multiple and hierarchical scanning processing on the same area of the workpiece to be processed. Through the prefabricated slag discharge scheme as shown in Figures 2-5 and the optimized processing path such as Figures 6-8 , the removal speed of molten slag can be significantly increased, the processing accuracy of the workpiece can be improved, a high processing quality can be achieved, and at the same time, the processing requirements with a larger depth can be met, and the processing of holes and grooves can be realized, etc.

[0029] The working principle of this embodiment is as follows: The incident laser beam 1 enters from the focusing lens 2 into the optical window 3, and passes through the optical window 3 to be coupled with the micro water jet 9 at the nozzle hole 7. Total internal reflection occurs inside the micro water jet 9, and the laser energy is transmitted to the processing surface of the workpiece 10 to be processed for processing. Utilizing the impact and cooling effects of the micro water jet 9, and with the assistance of the shielding gas 7 to protect the micro water jet 9, through the slag discharge implementation scheme in the present invention, the molten slag 11 generated during the processing is quickly removed, improving the processing efficiency.

[0030] Specific examples are applied in the present invention to elaborate on the principle and implementation manner of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, based on the idea of the present invention, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A water beam-guided laser processing technology and method for optimizing the slag discharge channel, characterized in that A method for improving the efficiency of water beam-guided laser processing by optimizing the design of the front-mounted downward slag discharge channel and utilizing the high-efficiency characteristics of continuous wave (CW-M) lasers, preferably quasi-continuous wave (QCW) lasers, or lasers with longer pulse widths.

2. The water beam guiding laser processing method and process for optimizing the slag discharge channel according to claim 1, characterized in that, The slag discharge channel is optimized, and there are but not limited to these two methods. Method 1 is to optimize the design of the front-mounted downward slag discharge channel; Method 2 is to preferably select the workpiece processing direction to improve the slag discharge speed during processing.

3. The water beam guiding laser processing method and process for optimizing the slag discharge channel according to claim 1, characterized in that, Based on the optimized design of the slag discharge channel, the residue during laser processing is not very limited by the upward discharge of the residue in the existing water-guided laser processing, and the high-efficiency characteristics of continuous wave lasers (CW-M), quasi-continuous wave (QCW) lasers, or lasers with longer pulse widths are preferably utilized to achieve a high-efficiency processing method for efficiently generating residue and effectively discharging it. The preferred laser wavelengths are 1064nm / 532nm / 355nm, the pulse width range is 200ns–50ms, the frequency range is 100Hz–80kHz, and the peak power range is 1-20kW.

4. In the water beam-guided laser processing method and process for optimizing the slag discharge channel according to claim 2, it is characterized in that Method 1 is to design a front-mounted downward slag discharge channel. Before water beam-guided laser processing of the workpiece, a through-hole or channel is prefabricated in the workpiece processing path using mechanical processing, electrical discharge machining, or laser processing methods. This channel is used to guide the processing residue and residual water during processing to quickly discharge downward through the prefabricated channel, preventing the accumulation effect of the melt and liquid flow from damaging the stable transmission of the water beam optical fiber and the effective conduction of the laser beam, and improving the processing efficiency.

5. In the water beam guiding laser processing method and process for optimizing the slag discharge channel according to claim 2, it is characterized in that Method 1 is to design a front-mounted downward slag discharge channel. For thick plate grooving, starting from the 5mm width direction at the edge of the scanning path, scan radially (perpendicular to the workpiece surface) multiple times or once to preferentially penetrate, then continue to feed the scanning path by 5mm, and repeat the above process until the entire path is scanned. A rapid slag discharge channel is first formed in the processing path to achieve an increase in the discharge speed of the molten slag and deposited liquid flow during water beam-guided laser processing, and improve the processing efficiency.

6. The water beam guiding laser processing method and process for optimizing the slag discharge channel according to claim 2, characterized in that, Method 2 preferably selects the workpiece processing direction, including placing the workpiece obliquely, changing the direction of the workpiece cutting thickness to the laser scanning direction, flipping the workpiece 180 degrees after machining half of the thickness to machine the other half of the depth, and increasing slag discharge by rotating for axisymmetric machining of rotating parts.

7. The water beam-guided laser processing method and process for optimizing the slag discharge channel according to claim 6, characterized in that, Set the inclination angle of the workpiece and utilize the gravity effect to achieve the smooth acceleration and discharge of the melt and liquid flow during water beam-guided laser processing, improve the continuous reliability of the water beam optical fiber entering the material interior and the stable effectiveness of laser conduction, and improve the processing efficiency.

8. In the water beam guiding laser processing method and process for optimizing the slag discharge channel according to claim 6, it is characterized in that, By preferably selecting the workpiece scanning strategy, cut the workpiece with its long (wide) cross-section replaced by a short (narrow) cross-section, or flip the workpiece 180 degrees after machining half of the thickness to machine the other half of the depth, shorten the slag discharge channel, and improve the efficiency of water beam-guided laser processing of materials.

9. The method for water beam-guided laser machining of a workpiece with an optimized slag discharge channel according to claim 6, characterized in that, During the processing of the axisymmetric surface of rotating parts, preferably select the part rotation feeding method to achieve rapid slag discharge and residual aqueous solution, and improve the processing efficiency.

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