Process method and system for laser composite efficient precision machining of blind hole

Abstract

The invention belongs to but not limited to the technical field of blind hole machining, and discloses a process method and system for laser composite efficient precision machining of blind holes, and the process method comprises a laser hole prefabricating stage and a laser fine hole repairing stage; a hole is preformed in the punching position of a workpiece through a large-pulse-energy laser beam, and fixed-point materials of the workpiece are rapidly removed; and then the hole is finely trimmed through ultra-short pulse width laser, the incident angle direction of a laser beam and the surface of the material is changed through a rotary cutting system, the hole wall and the hole bottom of the hole after the pre-hole stage are trimmed, fine trimming of the blind hole is completed, and the high-precision blind hole with the controllable taper is obtained. The method comprises the following steps: quickly removing a prefabricated blind hole in a workpiece material by using large pulse energy laser; adjusting process parameters, and quickly pre-processing a blind hole with a certain depth in a workpiece; and then the hole wall and the hole bottom of the blind hole are trimmed through high-speed rotating light beams and variable light beam incidence angles of the rotary cutting system, smooth hole wall, flat hole bottom and controllable taper of the blind hole are achieved, and the machining quality and efficiency of the blind hole of the difficult-to-machine material are improved.

Description

Technical Field

[0001] The present invention belongs to but is not limited to the technical field of blind hole processing, and in particular relates to a process method and system for laser composite high-efficiency and precision processing of blind holes. Background Art

[0002] Blind hole technology, as an important part of modern precision manufacturing technology, is gradually showing its unique value in many fields. From aerospace to electronic information, from biomedicine to precision instruments, the application of blind hole technology is becoming more and more extensive, playing an important role in improving product quality, enhancing performance, and reducing costs.

[0003] Blind vias are conductive holes that connect the surface layer and the inner layer without penetrating the entire board. Blind vias are relatively common in printed circuits. They are mostly located on the top and bottom surfaces of printed circuit boards and have a certain depth to connect the surface circuits with the inner layer circuits below.

[0004] Blind holes are usually processed by EDM and machining. However, it is difficult to break through the processing technology of EDM and machining for blind holes less than 100 microns. At the same time, EDM has low efficiency, requires conductive materials, and has complex post-processing procedures. Traditional machining has low efficiency for micro-hole processing of hard and brittle materials, complex procedures, high costs, and cannot process super-hard diamond materials. In the aerospace field, engine blades are multi-layer hollow structures, and laser processing of through holes is easy to damage the wall material. Laser processing of blind holes can effectively prevent laser damage to the wall material.

[0005] The main technical problems faced by existing technologies in blind hole processing include the following:

[0006] 1. Low processing efficiency: Traditional blind hole processing methods such as EDM and mechanical processing have significant deficiencies in efficiency. EDM is slow, especially when processing blind holes smaller than 100 microns, which is more time-consuming. Mechanical processing is also inefficient for micro-hole processing of hard and brittle materials, and it is difficult to meet the needs of modern industry for efficient production.

[0007] 2. Complex post-processing procedures: EDM requires the use of conductive materials, and complex post-processing procedures are required after processing to remove processing residues and improve the quality of the hole wall. This not only increases processing time, but also increases process complexity and cost. Mechanical processing also faces similar problems, especially when processing blind holes with complex shapes or high precision requirements, multiple processes are required to achieve the desired effect.

[0008] 3. High processing cost: Due to low processing efficiency and complex post-processing procedures, the cost of traditional blind hole processing methods is high. In addition, mechanical processing of micro-holes in hard and brittle materials often requires special equipment and tools, further increasing the cost. EDM is also expensive due to its special requirements and consumables.

[0009] 4. Poor environmental protection: Traditional blind hole processing methods perform poorly in terms of environmental protection. The waste liquid and gas generated during EDM processing are harmful to the environment and require additional treatment measures. The coolant and waste chips during mechanical processing also pollute the environment, increasing the burden of environmental treatment.

[0010] 5. Limited processing materials: Traditional methods have certain limitations in processing materials. For example, EDM can only be used for conductive materials, while mechanical processing is difficult to achieve ideal results when processing extremely hard materials such as superhard diamond materials. This limitation of material adaptability limits the application scope of traditional blind hole processing technology.

[0011] In general, the main problems existing in the existing technology in blind hole processing are concentrated in efficiency, complexity, cost, environmental protection and material adaptability, and they are in urgent need of improvement and breakthroughs through new process methods. Summary of the invention

[0012] In view of the problems existing in the prior art, the present invention provides a process method for laser composite high-efficiency and precision processing of blind holes, which completes the blind hole processing of the workpiece by pre-fabricating the hole with a large pulse energy laser beam, and then uses an ultra-short pulse width laser to complete the trimming of the side wall and bottom of the blind hole through beam rotation and angle deflection, so that the hole wall of the blind hole is smooth and the bottom of the hole is flat. Laser processing of blind holes improves the blind hole processing efficiency, processing quality and processing accuracy.

[0013] The present invention is implemented as follows: a process method for laser composite high-efficiency precision machining of blind holes, comprising the following steps:

[0014] S1, through the combination of high pulse energy laser and protective gas, quickly pre-form holes at the workpiece drilling site, remove materials at fixed points on the workpiece, and process blind holes of a certain depth and diameter at the workpiece drilling site;

[0015] S2, changing the direction of the ultrashort pulse laser beam through the rotary cutting system, so that the ultrashort pulse laser beam forms a rotating beam with a controllable incident angle, trimming the hole wall and hole bottom of the workpiece after the pre-hole stage, completing the blind hole trimming stage, and obtaining the target blind hole.

[0016] Furthermore, the workpiece material is superhard diamond material, ceramic material, metal material, non-metallic material, composite material and hard and brittle material.

[0017] Furthermore, the large pulse energy laser has modulated pulse energy, and the pulse energy can be adjusted according to the required blind hole size to pre-fabricate blind holes on the workpiece; the large pulse energy is above 1 millijoule; the pulse width of the ultrashort pulse laser is below 10 picoseconds.

[0018] Furthermore, the incident angle is the angle between the central axis of the laser beam and the axis of the processed hole. By controlling the incident angle of the laser beam, the taper of the hole during laser processing is controlled.

[0019] Furthermore, the peeling system includes a beam angle adjustment device, a beam rotation device, a focusing device and a gas assist device.

[0020] Furthermore, the direction of the ultrashort pulse width laser beam is changed by the rotary cutting system, so that the ultrashort pulse width laser beam self-rotates to form an hourglass-shaped beam, and the hole wall and hole bottom of the workpiece after the pre-hole stage are trimmed.

[0021] Furthermore, the ultrashort pulse width laser beam is rotated through the rotary cutting system and the incident angle with the material is controllable. The roundness and hole wall quality of the hole are trimmed by rotating the beam at the incident angle. Protective gas is required in the fine hole trimming stage to complete the blind hole trimming.

[0022] Another object of the present invention is to provide a laser composite high-efficiency precision blind hole processing system for a process method of laser composite high-efficiency precision blind hole processing, wherein the devices in the pre-hole stage include a laser, a chiller and a processing head, and the prefabricated blind hole is completed by emitting a large pulse energy laser by the laser; the devices in the hole repairing stage include a laser, a chiller, an optical path system and a rotary cutting head, and the blind hole is repaired by emitting an ultra-short pulse width laser beam through the optical path system and the rotary cutting head by the laser, thereby achieving precise blind hole processing.

[0023] Furthermore, the processing head and the rotary cutting head are mounted on the Z-axis slide, the workpiece to be processed is placed on the XY-axis slide, and the XYZ-axis slide is combined into a multi-axis CNC system; the multi-axis CNC system is equipped with CNC systems of different structures according to the hole posture requirements of the workpiece to be processed, so as to meet the hole processing requirements of complex workpieces in different vector directions in space, such as a five-axis linkage CNC system with two rotation axes and three linear axes, so as to meet the positioning and processing requirements of multiple degrees of freedom of the workpiece.

[0024] Furthermore, the large pulse energy laser emitted by the laser is transmitted to the processing head to remove material from the workpiece at a fixed point, and a blind hole of a certain depth and diameter is processed at the drilling location of the workpiece. The chiller removes the heat in the laser by circulating water to ensure stable operation of the laser; an ultra-short pulse width laser beam is emitted by the laser and transmitted to the rotary cutting head through the optical path system, causing the beam to rotate and the angle to deflect to achieve hole wall and hole bottom trimming. At the same time, the water circulation function of the chiller ensures stable operation of the laser.

[0025] In combination with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0026] First, the present invention uses a laser beam to drill holes on the surface of the material, thereby reducing the blind hole processing time and improving production efficiency. At the same time, ultra-short pulse width femtosecond laser rotary cutting is used to accurately repair the holes, and the tapered holes generated in the blind hole stage are revised to make them flat, thereby improving the hole quality. Compared with the current technical means, the present invention improves the processing efficiency and quality of micro-hole blind holes, and at the same time expands the blind hole processing limit to smaller scales and a wider range of materials.

[0027] The present invention has a wide range of material applicability, is green and environmentally friendly, has low cost, improves product processing efficiency and quality, and makes the blind hole processing diameter range 0.015mm-1mm, with a hole depth-to-diameter ratio greater than 20:1. The material can be hard and brittle materials such as diamond, ceramic, glass, metals such as stainless steel and high-temperature alloys, composite materials such as CFRP, and other metal and non-metal materials. The processing time for a single hole is less than 10 seconds, and the processing size error is less than 0.5 microns.

[0028] Second, the present invention solves the problems of low efficiency, insufficient precision, and material damage in the process of blind hole processing in the prior art, as well as the problem that many hard-to-process hard and brittle materials and composite materials cannot be processed. In traditional blind hole processing methods, it is often difficult to take into account both speed and precision at the same time, resulting in low processing efficiency and failure to meet the needs of modern industry for efficient and precise processing. Conventional laser processing technology is prone to thermal damage and thermal deformation of materials, especially when processing hard and brittle materials and composite materials, which can easily produce cracks and microcracks, affecting the quality and service life of the product. The present invention takes advantage of laser processing and adopts a macro-micro combination method to achieve large-scale and high-efficiency material removal at the macro level, and achieve precision material stripping at the micro level to achieve recast layer-free processing, ultimately obtaining high-quality blind holes.

[0029] By using a large pulse energy laser combined with a protective gas to quickly preform holes, the processing time of a single blind hole is less than 1 second. The present invention significantly improves the efficiency of blind hole processing. The large pulse energy laser can remove a large amount of material in a short time, and the use of a protective gas prevents oxidation and contamination of the material, thereby improving the quality of the preformed hole. At the same time, the heat-affected zone of material processing is controlled to avoid large-scale damage to the material caused by high temperature, ensuring low damage to the material during processing and providing a guarantee for the next stage of hole repair.

[0030] In the hole repairing stage, the present invention adopts a method combining a rotary cutting system and an ultrashort pulse width laser to achieve high-precision blind hole repair. The rotary cutting system controls the incident angle of the laser beam, and the beam rotates at high speed around the hole axis, so that the laser beam can act evenly on the hole wall and the hole bottom, removing the recast layer left by the early large pulse energy rapid hole making and solving the problem of low roundness. At the same time, it solves the taper problem caused by the fixed laser beam angle in the traditional processing method, and finally obtains a taper-controllable blind hole. With its extremely short pulse width and high peak power, the ultrashort pulse width laser can achieve high precision in picoseconds (10-12 seconds) or femtoseconds (10 -15 The material removal is completed within 10 seconds, which significantly improves the processing accuracy and ensures the accuracy and quality of the blind hole.

[0031] The present invention has also achieved significant technical progress in terms of adaptability to a variety of materials. The process method is not only applicable to metal materials, but can also efficiently process superhard diamond materials, ceramic materials, composite materials and other hard and brittle materials. This wide applicability makes the present invention have great promotion value in various industrial applications, can meet the needs of different industries for efficient and precise processing, improve product quality and reliability, significantly extend service life, and reduce manufacturing costs.

[0032] Third, the expected benefits and commercial value of the technical solution of the present invention after transformation are as follows: Taking the processing of film holes in aircraft engine blades as an example, the current hole making of aircraft engine blades adopts electrospark technology. The hole making time varies slightly according to the hole depth. The target electrospark single hole time is 30-40 seconds, and the effective hole making time of the present invention is controlled at 10-15 seconds; there is a 5-10 micron recast layer on the hole wall processed by electrospark, and the recast layer is invisible when the hole is made by femtosecond laser through rotary cutting technology. The efficiency and quality of film hole making of aircraft engines are significantly improved and the environment is protected. The processing efficiency of film holes in aircraft blades is improved by 2-3 times, and the quality is guaranteed.

[0033] (2) The technical solution of the present invention fills the gap in the technology of the industry at home and abroad: The present invention fills the gap in the efficient and high-quality processing of blind holes by composite laser at home and abroad. The large pulse laser controls the hole depth by adjusting the pulse energy, duty cycle, frequency and other parameters, and the ultra-short pulse rotary cutting laser controls the hole accuracy and taper and other precision indicators. Through the laser composite method and process innovation, the efficiency, capability and quality of laser in processing blind holes and micro holes are improved.

[0034] The technical solution of the present invention solves the technical problems that people have been eager to solve but have never succeeded in solving: the technical solution of the present invention solves the technical problem of efficient laser processing of high-quality controllable taper blind holes, and overcomes the technical problem of efficient and high-quality processing of blind holes under complex working conditions without damaging the underlying materials. The problem of damaging the opposite wall during laser processing of complex cavities has always been a problem that has not been technically broken through. The present invention provides a solution for laser processing of blade air film holes without damaging the opposite wall.

[0035] The technical solution of the present invention overcomes technical prejudice: the technical solution of the present invention overcomes the prejudice that laser can only perforate but cannot process high-quality blind holes. Through technical solution design and process optimization, laser processing of high-quality blind holes can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1is a schematic diagram of a wedge prism peeling process provided by an embodiment of the present invention;

[0037] Figure 2 is a schematic diagram of the rotary cutting process of a dove prism provided in an embodiment of the present invention;

[0038] Figure 3 Schematic diagram of three laser peeling processing modes provided by an embodiment of the present invention;

[0039] Figure 4 This is a flow chart of a process method for laser composite efficient and precise blind hole machining provided by an embodiment of the present invention;

[0040] Figure 5 This is a physical picture of the prefabrication of an orifice by large pulse laser energy provided by an embodiment of the present invention;

[0041] Figure 6 It is a schematic diagram of a cross section of a hole wall preformed by large pulse laser energy provided by an embodiment of the present invention;

[0042] Figure 7 This is a real picture of the orifice after being trimmed by ultrashort pulse width laser provided by an embodiment of the present invention;

[0043] Figure 8 is a schematic diagram of a cross-section of a hole wall after ultrashort pulse width laser trimming provided by an embodiment of the present invention;

[0044] Fig. 9 It is a schematic diagram of a hole cross section of a large pulse energy laser prefabricated hole simulated processing provided by an embodiment of the present invention;

[0045] Fig.10 is a hole detection data diagram provided by an embodiment of the present invention without using the processing of the present invention;

[0046] Fig.11 This is a data diagram of the detection hole after using the present invention provided by the embodiment of the present invention.

[0047] Fig.12 It is a schematic diagram of avoiding laser damage to the opposite wall after using the present invention provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0048] 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 embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0049] The process method for laser composite efficient and precise blind hole processing provided by the embodiment of the present invention combines two laser technologies to achieve efficient and precise blind hole processing. First, in step S1, a high pulse energy laser is used in combination with a protective gas to quickly preform an initial hole on the workpiece. The high pulse energy laser can quickly remove material to form a blind hole with a certain depth and diameter. The purpose of this step is to quickly remove most of the material to form the basic shape of the blind hole.

[0050] Next, in step S2, the rotary cutting system is used to change the direction of the ultrashort pulse laser beam to form a rotating beam with a controllable incident angle. This rotating beam can finely trim the hole wall and bottom after the prefabricated hole to achieve higher precision and surface quality. The characteristics of the ultrashort pulse laser beam are concentrated energy and short action time, so it can effectively reduce the heat affected zone and improve processing accuracy.

[0051] Through this composite process method, blind holes that meet the requirements can be processed efficiently and accurately.

[0052] like Figure 1 In the scheme 1 shown, the laser beam enters the optical rotation system, and the beam angle is deflected by adjusting the spacing between four optical axes. The four optical axes of the optical rotation system are driven by a motor to rotate, generating a rotating beam, which is then focused onto the workpiece surface by a focusing mirror to form a rotating beam with a variable angle.

[0053] like Figure 2 In the second scheme shown, the laser beam enters the Dove prism to form a rotating beam, and then enters three wedge prisms, which change the incident angle of the beam. Finally, the beam is focused onto the surface of the material by a focusing lens to form a rotating beam with a controllable incident angle.

[0054] The optical rotation system in the present invention forms a rotating beam with a variable angle by precisely adjusting the angle and incident path of the light beam, which is suitable for the field of laser processing and can improve processing accuracy and efficiency. Its working principle is divided into the following parts:

[0055] First, the laser beam enters the optical rotation system through the light source. The system is equipped with four optical wedges, and the spacing of each optical wedge can be adjusted by an adjustment mechanism. The change in the spacing of the optical wedges affects the path and angle deflection of the light beam. The optical wedge is driven by a motor to rotate. When the light beam passes through the rotating optical wedge, a rotating light beam is generated. The angle of the light beam changes with the rotation of the optical wedge, thereby realizing dynamic control of the light beam direction.

[0056] Secondly, the rotating beam generated by the optical rotation system passes through the focusing lens to focus the laser beam onto the workpiece surface. The focusing lens can not only focus the beam on a focal point, but also further optimize the incident angle and focal position of the beam by dynamically adjusting the position and angle of the focusing lens, so that a rotating beam with a variable angle is formed during the laser processing process to meet the processing requirements of different workpieces.

[0057] In addition, the system can also use a dove prism to rotate and modulate the beam. The laser beam rotates after passing through the dove prism and enters three wedge prisms. Each wedge prism can adjust its tilt angle according to the set parameters, thereby changing the incident angle of the beam, so that the final beam can be focused on the material surface at different angles. This design improves the flexibility of the beam and can adapt to workpieces of different materials and shapes.

[0058] Finally, the light beam modulated by the Dove prism and the wedge prism passes through the focusing lens again to accurately focus the light beam on the material surface. Since the various components in the system can be dynamically adjusted according to real-time needs, the incident angle and rotation speed of the laser beam can be controlled, thereby achieving higher processing accuracy. The system is particularly suitable for processing scenarios that require complex beam path control, ensuring uniform beam distribution and precise incident angle during material processing, ultimately improving the overall processing quality.

[0059] The following are two specific embodiments:

[0060] Example 1: Processing blind holes in superhard diamond material

[0061] 1. Select a piece of superhard diamond material as the workpiece and determine the location where the blind hole needs to be processed.

[0062] 2. In step S1, a high pulse energy laser is used in combination with a protective gas (such as nitrogen) to quickly preform an initial hole in the diamond material. Due to the extremely high hardness of the diamond material, appropriate laser parameters need to be selected to ensure effective removal of the material.

[0063] 3. After the prefabrication is completed, enter step S2. The direction of the ultrashort pulse width laser beam is adjusted by the rotary cutting system to form a rotating beam to trim the hole wall and hole bottom. The use of ultrashort pulse width laser beam can reduce the heat affected zone and improve the processing accuracy.

[0064] 4. After trimming, the target blind hole is obtained. The accuracy and quality of the blind hole can be checked using a microscope or other equipment.

[0065] Example 2: Processing blind holes in metal materials

[0066] 1. Select a piece of metal material (such as stainless steel) as the workpiece and determine the location of the blind hole.

[0067] 2. In step S1, a high pulse energy laser is used in combination with a protective gas (such as argon) to quickly preform initial holes in metal materials. Metal materials have good thermal conductivity, so appropriate laser parameters need to be selected to avoid excessive thermal effects.

[0068] 3. Enter step S2 and use the rotary cutting system to adjust the direction of the ultrashort pulse width laser beam to finely trim the hole wall and bottom of the metal material. Due to the good ductility of metal materials, it is necessary to control the incident angle and rotation speed of the laser beam during the trimming process to ensure the accuracy and surface quality of the blind hole.

[0069] 4. After finishing, a metal blind hole that meets the requirements is obtained. The accuracy and quality of the blind hole can also be verified using relevant equipment.

[0070] The embodiment of the present invention provides a process method for laser composite high-efficiency precision machining of blind holes. The method can be used in the rotary cutting and hole repairing stage. Figure 1 As shown, the laser beam passes through the lens group to form a light path with geometric characteristics. The light path enters the peeling system through a 45-degree full reflection mirror. The peeling system changes the deflection angle of the light beam and the material to be processed in the direction of the hole axis and generates the self-rotation of the light beam, that is, the self-rotation rotates around the optical axis. During processing, the self-rotation rotates around the axis of the processed hole. The principle diagram of the peeling light path scheme of Dove prism can also be used in the peeling hole repairing stage. Figure 2 As shown in the figure, three typical processing modes of laser rotary cutting to trim blind holes form different hole tapers as shown in the figure. Figure 3 shown.

[0071] 1. Prefabrication stage (step S1):

[0072] High pulse energy laser drilling: In this stage, a high pulse energy laser is used for drilling. The laser emits a high energy laser beam, which generates high temperature on the surface of the workpiece after focusing, quickly melts and evaporates the material, and forms a prefabricated hole. In this process, the pulse energy and frequency of the laser need to be precisely controlled to ensure that the depth and diameter of the hole meet the expected requirements.

[0073] Use of shielding gas: During the laser drilling process, shielding gas (such as nitrogen, argon, etc.) is used to prevent the workpiece material from oxidation at high temperatures, and at the same time helps to blow away the molten and evaporated materials, improving the drilling efficiency and quality.

[0074] Fixed-point material removal: Fixed-point material removal is achieved by controlling the laser scanning path and drilling position. This step ensures the accurate position of the prefabricated hole and forms a blind hole of a certain depth and diameter, laying the foundation for the subsequent finishing stage.

[0075] 2. Hole repairing stage (step S2):

[0076] Peeling system: Peeling system is used in the hole repair stage to change the direction of the ultra-short pulse width laser beam. The peeling system can control the incident angle of the laser beam so that the laser beam is incident on the hole wall and bottom at different angles, thereby achieving uniform trimming of the inner surface of the blind hole.

[0077] Ultrashort pulse laser: Use ultrashort pulse laser (such as picosecond or femtosecond laser) combined with protective gas for fine finishing. Ultrashort pulse laser can generate high-intensity light pulses in a very short time, so that the material can be removed with a very small heat-affected zone, avoiding thermal damage and thermal deformation of the material and improving processing accuracy.

[0078] Controllable rotating beam: The rotary cutting system allows the laser beam to be incident into the blind hole in a controllable rotating manner. By adjusting the incident angle, the action position and action time of the laser beam can be accurately controlled, thereby comprehensively trimming the hole wall and bottom of the prefabricated hole and eliminating defects and unevenness in the prefabricated hole stage.

[0079] Target blind hole formation: After precise trimming by the rotary cutting system, the size and shape of the prefabricated hole are further optimized, and the surface quality of the hole wall and hole bottom is significantly improved, ultimately forming a target blind hole that meets the design requirements.

[0080] 3. Workpiece material:

[0081] Adaptability to multiple materials: This process is applicable to a variety of materials, including super-hard diamond materials, ceramic materials, metal materials, non-metallic materials, composite materials and hard and brittle materials. Each material requires targeted parameter adjustment during processing to adapt to its different physical and chemical properties, but the overall process steps and principles are the same.

[0082] like Figure 4 As shown, the method includes a pre-hole stage and a hole repair stage; specifically includes the following steps:

[0083] S1, through the combination of high pulse energy laser and protective gas, quickly pre-form holes at the workpiece drilling site, remove materials at fixed points on the workpiece, and process blind holes of a certain depth and diameter at the workpiece drilling site, which is convenient for subsequent ultra-short pulse width laser beam trimming;

[0084] S2, change the direction of the ultrashort pulse width laser beam through the rotary cutting system, so that the ultrashort pulse width laser beam forms a rotating beam with controllable incident angle, and the hole wall and hole bottom of the workpiece after the pre-hole stage are trimmed with the protective gas, completing the blind hole trimming stage and obtaining the target blind hole. The ultrashort pulse width laser beam trims the hole wall and hole bottom of the blind hole through beam rotation and angle deflection, making the hole wall of the blind hole smooth and the hole bottom flat, improving the processing quality and processing efficiency of the blind hole.

[0085] The large pulse energy is above 1 millijoule; the pulse width of the ultrashort pulse laser is below 10 picoseconds.

[0086] The rotary cutting system includes a first wedge prism, a second wedge prism, a third wedge prism and a fourth wedge prism. The first wedge prism and the second wedge prism are wedge prisms with the same wedge angle. The first wedge prism or the second wedge prism is connected to an up and down linear motion mechanism and can move up and down along the axis. The third wedge prism and the fourth wedge prism are wedge prisms with the same wedge angle. The third wedge prism or the fourth wedge prism is connected to a rotating mechanism and can rotate around the axis. The light path is injected into the rotary cutting system. The rotating axis of the rotary cutting system is coaxial with the optical axis. The motor drives the device to rotate around the axis, so that the focused light spot also moves in a circle along the axis to form laser ring cutting. The laser beam acts on the material through the wedge prism in the rotary cutting system and the trimming of the focusing mirror at the output end of the rotary cutting system, and the material is removed at a fixed point to form a blind hole.

[0087] In the embodiment of the present invention, a large pulse energy laser is used to perform a pre-hole stage at the workpiece drilling site. Within a controllable tolerance range, the large pulse energy laser is combined with a protective gas to perform fixed-point material removal on the workpiece; then the workpiece is moved to the position directly below the ultra-short pulse width rotary cutting laser to perform hole expansion and hole repair. The direction of the ultra-short pulse width laser beam is changed by a lens group, so that the ultra-short pulse width laser beam self-rotates to form an hourglass-shaped beam, and the hole wall and hole bottom of the workpiece drilling site after the pre-hole stage are trimmed to increase the roundness of the target blind hole and the smoothness of the hole wall, thereby obtaining the target blind hole. In this process, the material is placed on the multi-axis CNC system processing platform, and during processing, the material is moved from one processing point on the processing platform to another processing point on the processing platform through the XY axis slide; the height of the laser processing is adjusted by the processing head and rotary cutting head mounted on the Z axis slide.

[0088] When machining a 0.1 mm diameter round hole, the first step is to enter the pre-hole stage. Under the action of the large pulse energy laser, the workpiece quickly processes a nearly round hole with a diameter of 0.08 mm. The large pulse laser energy preforms the hole. Figure 5 As shown in the figure, the pre-laser processed hole is within the controllable tolerance range, and then laser processed by the rotary cutting system to make the circular hole diameter 0.1 mm. The target hole needs to be processed in the hole repair stage, and the hole wall and hole bottom are trimmed by beam deflection and angle deflection. The hole mouth after ultra-short pulse width laser trimming is as follows Figure 7 As shown. The pre-hole stage devices include lasers, chillers and processing heads. The laser emits a large pulse energy laser to complete the prefabrication of blind holes. The repair stage devices include lasers, chillers, optical path systems and rotary cutting heads. The laser emits an ultra-short pulse width laser beam through the optical path system and rotary cutting head to complete the blind hole repair, so as to achieve precise blind hole processing. The processing head and rotary cutting head are mounted on the Z-axis slide, and the workpiece to be processed is placed on the XY-axis slide. The XYZ-axis slide is combined into a multi-axis CNC system.

[0089] In this embodiment, a large pulse energy laser is used to prefabricate blind holes in the workpiece, and the energy released by the large pulse energy laser is used to remove material from the workpiece at a fixed point, and a blind hole of a certain depth and width is processed at the workpiece drilling location, which is convenient for subsequent ultra-short pulse width laser beam trimming. Fig. 9 As shown in the figure, when the large pulse energy laser processes the material, the surface of the material is affected by the shock wave, causing wrinkles on the surface of the material, and causing damage around the surface of the material to form slag; the interior of the material is affected by the large pulse energy laser to form a heat-affected zone, and the energy of the large pulse energy laser propagates heat in the heat-affected zone. The shock wave generated by the large pulse energy laser in the material diffuses from the direction close to the long pulse laser to the direction away from the long pulse laser, and small cracks are generated on the hole wall along the direction close to the long pulse laser to the direction away from the long pulse laser. The energy of the large pulse energy laser has a high peak in the middle and a weak peak at the edge. When it acts on the workpiece, it is easy to form a V-shaped cone hole, so secondary trimming is required to make the hole wall and the bottom of the target blind hole parallel and smooth. The ultrashort pulse width laser beam trims the hole wall and the bottom of the blind hole through beam deflection and angle deflection, making the hole wall and the bottom of the blind hole parallel and smooth, thereby improving the quality and processing efficiency of the blind hole. The large pulse energy laser emitted by the laser is transmitted to the processing head to remove material from the workpiece at a fixed point, and a blind hole of a certain depth and diameter is processed at the drilling location of the workpiece. The chiller removes the heat in the laser by circulating water to reduce the temperature of the laser; the ultra-short pulse width laser beam is emitted by the laser and transmitted to the rotary cutting head through the optical path system, causing the beam angle to deflect to achieve hole wall and hole bottom trimming, and at the same time the temperature of the laser is reduced by the circulation function of the chiller.

[0090] The present invention uses a high-energy laser to drill and punch holes on the front of the material and combines it with a rotary cutting laser for precise hole repair, greatly improving the production efficiency and processing quality of blind holes; it can also process micro blind holes without taper and complete dozens or even hundreds of high-precision blind holes in a few minutes. The present invention has a wide range of material applicability, is green and environmentally friendly, improves product processing efficiency and quality, and enables the blind hole processing of metal or non-metal materials with a diameter less than 1mm and a hole depth greater than 6mm in less than 10 seconds, and the processing size error is less than 0.5 microns, reducing costs.

[0091] like Fig.10 As shown, without using the present invention, the processed holes are all unqualified in inspection.

[0092] like Fig.11 As shown, after using the present invention, the hole roundness is improved, the hole wall is clean and free of dirt, and the detected holes are all qualified.

[0093] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by any technician familiar with the technical field within the technical scope disclosed by the present invention and within the spirit and principle of the present invention should be covered by the protection scope of the present invention.

Claims

1. A process for high-efficiency and precise laser composite blind hole machining. It is characterized in that The following steps are involved: S1, through the combination of high pulse energy laser and protective gas, quickly pre-form holes at the workpiece drilling site, remove materials at fixed points on the workpiece, and process blind holes of a certain depth and diameter at the workpiece drilling site; S2, changing the direction of the ultrashort pulse laser beam through the rotary cutting system, so that the ultrashort pulse laser beam forms a rotating beam with a controllable incident angle, trimming the hole wall and hole bottom of the workpiece after the pre-hole stage, completing the blind hole trimming stage, and obtaining the target blind hole.

2. The laser composite high-efficiency precision processing method for blind holes according to claim 1, It is characterized in that The workpiece materials include super-hard diamond materials, ceramic materials, metal materials, non-metallic materials, composite materials and hard and brittle materials.

3. The laser composite high-efficiency precision processing method for blind hole according to claim 1, It is characterized in that Large pulse energy laser has modulated pulse energy, and the pulse energy and pulse quantity can be adjusted according to the required blind hole size to prefabricate blind holes on the workpiece; the large pulse energy is above 1 millijoule; the pulse width of the ultrashort pulse laser is below 10 picoseconds.

4. The laser composite high-efficiency precision processing method for blind hole according to claim 1, It is characterized in that The incident angle is the angle between the center axis of the laser beam and the axis of the processed hole. By controlling the incident angle of the laser beam, the taper of the hole during laser processing is controlled.

5. The laser composite high-efficiency precision processing method for blind hole according to claim 1, It is characterized in that The peeling system comprises a beam angle adjustment device, a beam rotation device, a focus fixing device and a gas assist device.

6. The laser composite high-efficiency precision processing method for blind hole according to claim 1, It is characterized in that The direction of the ultrashort pulse laser beam is changed by the rotary cutting system, so that the ultrashort pulse laser beam self-rotates to form an hourglass-shaped beam, and the hole wall and hole bottom of the workpiece after the pre-hole stage are trimmed.

7. The laser composite high-efficiency precision processing method for blind hole according to claim 1, It is characterized in that The ultrashort pulse width laser beam is rotated by the rotary cutting system and the incident angle with the material is controllable. The roundness and hole wall quality of the hole are trimmed by rotating the beam at the incident angle. Protective gas is required in the fine hole trimming stage to complete the blind hole trimming.

8. A laser composite high-efficiency and high-precision blind hole processing system according to any one of claims 1 to 7, It is characterized in that The laser, chiller and processing head are connected through an optical path. The laser is responsible for emitting a large pulse energy laser, which is transmitted to the processing head through the optical path and is used to remove material from the workpiece at a fixed point to process blind holes. At the same time, the chiller is connected to the laser through a circulating water cooling system to take away the heat generated by the laser during operation and ensure the stable operation of the laser.

9. The laser composite high-efficiency precision blind hole processing system as claimed in claim 8, It is characterized in that The processing head and the peeling head are installed on the Z-axis slide and can move along the Z-axis direction, while the workpiece to be processed is placed on the XY-axis slide and can move in the XY plane; the Z-axis slide, the XY-axis slide and the additional rotating axis together constitute a multi-axis CNC system, which can realize blind hole processing of complex workpieces in different vector directions in space by precisely controlling the movement of each axis.

10. The laser composite high-efficiency precision blind hole processing system as claimed in claim 9, It is characterized in that An ultrashort pulse width laser beam is generated by a laser and accurately transmitted to the peeling head through an optical path system. The peeling head is designed with a rotating mechanism, which enables the laser beam to rotate inside the peeling head and deflect at an angle, thereby trimming the hole wall and bottom of the blind hole. During this process, the chiller continuously provides cooling for the laser through a water circulation cooling system to ensure its stability during long-term operation.

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