Ultrasonic laser combined machining head for millimeter-scale aperture

Abstract

The invention relates to the technical field of ultrasonic laser combined machining, in particular to a millimeter-level aperture ultrasonic laser combined machining head which comprises a machining head body used for conducting ultrasonic laser combined machining on a micropore, and a beam splitting reflector used for conducting beam splitting on pulse laser is arranged in the machining head body. An ultrasonic device used for transmitting ultrasonic shock waves to the machining head is arranged at the end, extending out of the micropore, of the machining head, a rotating device used for driving the machining head to rotate is arranged at the end, away from the machining head, of the ultrasonic device, and a telescopic device used for driving the rotating device to horizontally reciprocate is arranged at the bottom of the rotating device. A supporting base is slidably connected to the end, away from the rotating device, of the ultrasonic device and fixedly connected with the telescopic device. The machining head can conduct pulse laser and ultrasonic combined machining on the micro-hole, the hole diameter inner wall surface of the millimeter-level micro-hole can be effectively strengthened through pulse laser and ultrasonic combined machining, and the abrasion resistance and corrosion resistance of the millimeter-level micro-hole are improved.

Description

Technical Field

[0001] The invention relates to the technical field of ultrasonic laser composite processing, and in particular to an ultrasonic laser composite processing head for millimeter-level apertures. Background Art

[0002] Millimeter-level holes are of indispensable importance in the fields of aerospace, automobiles, and energy equipment. They are widely used in key links such as propulsion systems, lubrication systems, cooling systems, and air tightness testing, directly affecting the performance, efficiency, and safety of the equipment. The precise design and control of these tiny apertures play a key role in improving the operating efficiency of the overall system, reducing wear, ensuring air tightness, and extending service life. However, the millimeter-level aperture will wear due to friction during use, and the material around the aperture may suffer fatigue damage under frequent loading and unloading conditions, and may be affected by corrosion in harsh environments. These effects will cause the millimeter-level aperture to deteriorate in accuracy, crack and fracture, and surface quality. Therefore, there is an urgent need for an ultrasonic laser composite processing head for millimeter-level apertures that can effectively strengthen the inner wall surface of the millimeter-level microholes, improve their wear resistance and corrosion resistance, and extend the service life of the holes. Summary of the invention

[0003] The purpose of the present invention is to provide an ultrasonic laser composite machining head for millimeter-level apertures to solve the problems existing in the above-mentioned prior art.

[0004] To achieve the above-mentioned purpose, the present invention provides the following scheme: an ultrasonic laser composite processing head for millimeter-level apertures, comprising a processing head for performing ultrasonic laser composite processing on microholes, a beam splitting reflector for splitting pulsed lasers is arranged inside the processing head, an ultrasonic device for transmitting ultrasonic shock waves to the processing head is arranged at one end of the processing head extending outside the microhole, a rotating device for driving the processing head to rotate is arranged at one end of the ultrasonic device away from the processing head, a telescopic device for driving the rotating device to reciprocate horizontally is arranged at the bottom of the rotating device, and a support seat is slidably connected to one end of the ultrasonic device away from the rotating device, and the support seat is fixedly connected to the telescopic device.

[0005] Preferably, the processing head includes a processing head shell detachably connected to the ultrasonic device, the beam splitting reflector is arranged at an end of the processing head shell away from the ultrasonic device, each reflecting surface of the beam splitting reflector is respectively provided with a protective mirror through a focusing mirror, and the protective mirror passes through the outer wall of the processing head shell and is embedded in the outer wall of the processing head shell.

[0006] Preferably, a first ball is respectively arranged between two adjacent protective mirrors, the first ball passes through the processing head shell and extends out of the processing head shell, and the part of the first ball extending into the processing head shell is arranged in the ultrasonic device.

[0007] Preferably, the ultrasonic device comprises a horn threadedly connected and communicated with the machining head housing, one end of the horn away from the machining head housing is connected to an ultrasonic spindle via an ultrasonic transducer, and the ultrasonic spindle passes through the rotating device.

[0008] Preferably, a plurality of ball grooves are provided at the connection between the amplitude changing rod and the processing head housing, and the ball grooves are arranged in one-to-one correspondence with the first balls.

[0009] Preferably, through holes for providing a propagation channel for the pulsed laser are respectively opened in the centers of the machining head housing, the amplitude transformer and the ultrasonic main shaft, and the central axes of all the through holes are on the same central axis.

[0010] Preferably, the beam splitting reflector is installed in an end of the through hole of the processing head housing away from the amplitude transformer.

[0011] Preferably, the rotating device includes a hollow conductive slip ring chamber sleeved on the ultrasonic main shaft, the hollow conductive slip ring chamber is detachably connected to the ultrasonic transducer, a worm gear housing and a worm housing are provided at one end of the hollow conductive slip ring chamber away from the ultrasonic transducer, a worm gear is rotatably connected in the worm gear housing, the worm gear is mounted on the ultrasonic main shaft, the worm gear is meshed with a worm, the worm is rotatably connected in the worm housing, and one end of the worm bearing of the worm extending outside the worm housing is transmission-connected to a second drive motor.

[0012] Preferably, the telescopic device includes a lead screw arranged below the worm housing, the lead screw is threadedly connected to a nut seat, the top surface of the nut seat is fixedly connected to the bottom surface of the worm housing, one end of the lead screw is rotatably connected to the support seat, and the other end of the lead screw is rotatably connected to a screw fixer.

[0013] Preferably, the support seat comprises a screw support seat rotatably connected to the lead screw, the top surface of the screw support seat is fixedly connected to an ultrasonic device support seat, and the ultrasonic device support seat is slidably connected to the ultrasonic device.

[0014] The present invention discloses the following technical effects:

[0015] The present invention drives the rotating device to move horizontally through the telescopic device, and the rotating device drives the ultrasonic device to rotate, so that the processing head can perform pulse laser and ultrasonic composite processing on the microhole, so that the pulse laser and ultrasonic composite processing can effectively strengthen the inner wall surface of the millimeter-level microhole, improve the wear resistance and corrosion resistance of the millimeter-level microhole, and extend the service life of the millimeter-level microhole. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0018] Figure 2 It is a schematic diagram of the structure of the telescopic device of the present invention;

[0019] Figure 3 It is a schematic diagram of the structure of the rotating device of the present invention;

[0020] Figure 4 It is a schematic diagram of the structure of the ultrasonic device of the present invention;

[0021] Figure 5 It is a schematic diagram of the cross-sectional structure of the ultrasonic device of the present invention;

[0022] Figure 6 For the present invention Figure 5 The enlarged structural diagram at A in the middle;

[0023] Figure 7 It is a schematic diagram of the top view of the structure of the processing head of the present invention;

[0024] Figure 8 This is a schematic diagram of the pulse laser beam splitting and refraction of the present invention;

[0025] Fig. 9 This is the pulse laser optical path diagram of the present invention;

[0026] Fig.10 This is a schematic diagram of the laser action of the present invention;

[0027] Fig.11 This is a schematic diagram of the ultrasonic rolling action of the present invention;

[0028] Among them, 1. telescopic device; 11. first drive motor; 12. coupling; 13. screw fixer; 14. lead screw; 15. nut seat; 16. slider; 17. support seat; 171. ultrasonic device support seat; 172. screw support seat; 18. guide rail; 2. rotating device; 21. second drive motor; 22. ultrasonic spindle; 23. worm housing; 24. spindle bearing; 25. worm bearing; 26. worm; 27. worm wheel; 28. worm wheel housing; 29. ​​hollow conductive slip ring chamber; 291. housing connection; 292. protective cover; 293. Hollow conductive slip ring; 294. Bottom of protective sleeve; 3. Ultrasonic device; 31. Ultrasonic transducer; 311. Hexagon socket bolt; 314. Electrical copper sheet; 315. Vibrator; 32. Rotating base; 33. Fixing sleeve of ultrasonic device; 34. Screw; 35. Plane thrust ball bearing; 36. Amplitude transformer; 4. Processing head; 41. Processing head housing; 42. Beam splitting reflector; 43. First ball bearing; 44. Focusing lens; 45. Protective lens; 5. Pulse laser; 6. Hole wall; 7. Laser shock wave; 8. Ultrasonic shock wave; 9. Rotation direction. DETAILED DESCRIPTION

[0029] The possible implementation schemes found in the art are:

[0030] Laser and ultrasound combined technology is an advanced material processing technology that combines the high energy density of lasers and the mechanical effect of ultrasound to significantly improve the surface properties and internal structure of materials. The following are some specific aspects of the combined effect of laser and ultrasound on materials:

[0031] Microstructure improvement: Ultrasonic vibration can refine the molten pool formed during laser processing, promote the uniform growth of grains and the formation of equiaxed crystals, thereby improving the mechanical properties of the material.

[0032] Defect suppression: During laser repair or additive manufacturing, ultrasonic vibrations help suppress the formation of defects such as pores and cracks and improve the microstructure of the repaired area.

[0033] Improved hardness and strength: Ultrasonic vibrations can be used to achieve higher hardness and strength in laser-processed or repaired materials, which is particularly important for improving the material's wear resistance and load-bearing capacity.

[0034] Phase change control: Ultrasonic vibration can affect the phase change behavior during laser processing, such as reducing the precipitation of harmful phases and improving the thermal stability of materials.

[0035] Residual stress reduction: During laser processing, ultrasonic vibrations help reduce residual stress inside the material, reducing the risk of deformation and cracking.

[0036] Improved welding performance: For laser welding, ultrasonic vibration can improve the fluidity of the weld and the emission of metal vapor, improving the quality of the weld joint.

[0037] Tissue homogeneity: The use of ultrasonic vibrations in laser processing can make the material composition more uniform, helping to achieve a more uniform microstructure.

[0038] Processing accuracy and efficiency: Ultrasonic vibration can also improve the accuracy and efficiency of laser processing, especially in the manufacture of complex structures, enabling more precise processing control.

[0039] The combined action technology of laser and ultrasound has broad application prospects in improving material properties and processing quality.

[0040] In the existing technology, laser shock strengthening generates high-energy shock waves on the metal surface through laser pulses, implanting higher microhardness and residual compressive stress on the material surface and refining the material surface grains to a greater extent, which can improve the tensile strength, fatigue resistance and corrosion resistance of the metal material, thereby improving the surface properties of the material and extending its service life.

[0041] The invention patent with patent number CN202310612275X proposes a laser shock strengthening device and method for the inner wall of medium and large metal pipes. This patent can produce a deeper residual stress layer inside the pipe, change the microstructure and mechanical properties of the surface layer of the inner wall of the pipe, but it cannot be applied to the inner wall of a hole with a millimeter aperture. Laser shock strengthening faces the limitation of instantaneous shock waves, resulting in shallow plastic deformation, thin grain refinement layer and unstable performance, which limits performance improvement. Ultrasonic assisted technology came into being, combined with ultrasonic rolling, which efficiently transmits ultrasonic energy to the material surface, promotes work hardening and grain refinement, enhances hardness and residual stress, optimizes surface morphology, and significantly improves material quality.

[0042] The invention patent with patent number CN115198084A proposes an equipment and method for ultrasonic-assisted laser shot peening composite strengthening. The patent effectively realizes the combination of laser shock wave and ultrasonic shock wave, promotes the dynamic recrystallization behavior of the material, and prepares metal parts with ultrafine grain surface.

[0043] The invention patent with patent number CN110804692A proposes an ultrasonic vibration device for coaxial ultrasonic-assisted laser shot peening strengthening. This patent realizes propagation along the same axis inside the material and forms a coupled field, which can prepare a surface with ultrafine grains.

[0044] The invention patent with patent number CN112899467A proposes a real-time coupling device and method of laser shock wave and ultrasonic shock wave, which enhances the organization / stress strengthening or forming processing effect of metal materials.

[0045] However, these devices and methods cannot be applied to millimeter-level hole wall strengthening.

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] Embodiment 1

[0049] Reference Figure 1-Figure 11 The present invention provides an ultrasonic laser composite processing head for millimeter-level apertures, including a processing head 4 for performing ultrasonic laser composite processing on microholes, a beam splitting reflector 42 for splitting a pulse laser 5 is arranged inside the processing head 4, an ultrasonic device 3 for transmitting an ultrasonic shock wave 8 to the processing head 4 is arranged at one end of the processing head 4 extending out of the microhole, a rotating device 2 for driving the processing head 4 to rotate is arranged at one end of the ultrasonic device 3 away from the processing head 4, a telescopic device 1 for driving the rotating device 2 to reciprocate horizontally is arranged at the bottom of the rotating device 2, and a support seat 17 is slidably connected to one end of the ultrasonic device 3 away from the rotating device 2, and the support seat 17 is fixedly connected to the telescopic device 1.

[0050] The present invention drives the rotating device 2 to move horizontally through the telescopic device 1, and the rotating device 2 drives the ultrasonic device 3 to rotate, so that the processing head 4 can perform pulse laser and ultrasonic composite processing on the microhole, so that the pulse laser 5 and ultrasonic composite processing can effectively strengthen the inner wall surface of the millimeter-level microhole, improve the wear resistance and corrosion resistance of the millimeter-level microhole, and extend the service life of the millimeter-level microhole.

[0051] The present invention is suitable for materials such as aluminum alloy, titanium alloy, nickel-based alloy, stainless steel, etc. that require improved wear resistance, corrosion resistance and fatigue strength of millimeter-level elongated holes; it can process holes with a depth of 0-60 mm and a hole diameter of 5.3-15.0 mm; the rotation speed is 0-600 r / min; and the feed speed is 0.1-2 mm / s.

[0052] The laser power density of pulse laser 5 is 2-10GW / cm 2 , the spot diameter is 1-2mm, the frequency is 0-10Hz, and the overlap rate is 50%-70%.

[0053] When the processing head 4 works at the set speed, the laser shock wave 7 and the ultrasonic shock wave 8 act alternately to achieve a composite effect; the amplitude of the hardened layer and the residual compressive stress field and the depth of the affected layer are increased, the dislocation density and structural complexity inside the material are greatly increased, and the dynamic recrystallization process is promoted to form a deeper nanocrystalline layer.

[0054] A further optimized solution is that the processing head 4 includes a processing head shell 41 detachably connected to the ultrasonic device 3, a beam splitting reflector 42 is arranged in an end of the processing head shell 41 away from the ultrasonic device 3, and each reflecting surface of the beam splitting reflector 42 is respectively provided with a protective mirror 45 through a focusing mirror 44. The protective mirror 45 passes through the outer wall of the processing head shell 41 and is embedded in the outer wall of the processing head shell 41.

[0055] The beam splitting reflector 42 in the processing head 4 is installed in the axial center groove of the inner boss of the processing head 4 and is fixed by a three-claw pressure arm. The pulse laser 5 passes through the through hole of the processing head 4, is divided into three beams by the beam splitting reflector 42 and refracted. The angle between every two laser beams is 120°, and the refracted pulse laser forms a 90° angle with the inner wall of the hole; three focusing mirrors 44 are arranged circumferentially on the inner boss of the processing head 4 to focus the refracted pulse laser; three protective mirrors 45 and three first balls 43 are arranged circumferentially on the processing head 4. The protective mirrors 45 can prevent water or impurities from entering. The diameter of each first ball 43 is 1 mm, and the angle with the refracted and focused pulse laser is 60°.

[0056] The beam splitting reflector 42 is coated with a reflective film on three right-angled surfaces. There are sharp edges between the three right-angled surfaces without chamfering. The pulse laser 5 directly incident on the sharp edge is split into three laser beams. The optical path is deflected 90°, and the angle between every two laser beams is 120°; the three right-angled surfaces are coated with a gold-plated high-reflective film, and the reflectivity Ravg>95%; the damage threshold is:>1J / cm2, 20ns, 20Hz, @1064nm.

[0057] According to a further optimization scheme, a first ball 43 is respectively arranged between two adjacent protective mirrors 45 , the first ball 43 passes through the machining head shell 41 and extends out of the machining head shell 41 , and the portion of the first ball 43 extending into the machining head shell 41 is arranged in the ultrasonic device 3 .

[0058] According to a further optimization scheme, the ultrasonic device 3 includes a variable amplitude rod 36 threadedly connected and communicated with the machining head housing 41 , and one end of the variable amplitude rod 36 away from the machining head housing 41 is connected to the ultrasonic main shaft 22 through the ultrasonic transducer 31 , and the ultrasonic main shaft 22 passes through the rotating device 2 .

[0059] The ultrasonic device is 80 mm long and 60 mm in diameter.

[0060] The processing head 4 is connected to the amplitude changing rod 36 by threads. The inner boss of the processing head 4 is provided with external threads, and the amplitude changing rod 36 is provided with internal threads.

[0061] The ultrasonic device 3 is fixed to the bottom of the protective cover 294, that is, below the hollow conductive slip ring chamber 29, through a screw 34. After the ultrasonic transducer 31 is powered on, the electrical energy is converted into mechanical energy to generate ultrasonic waves, and the mechanical amplitude is amplified through the horn 36, and the amplitude is transmitted to the first ball 43 in the processing head 4, so that the first ball 43 vibrates.

[0062] One end of the horn 36 is installed in the ultrasonic device fixing sleeve 33 and is in concave-convex contact with the vibrator 315, and the other end is threadedly connected to the processing head 4; a plane thrust ball bearing 35 is provided between the rotating base 32 and the ultrasonic device fixing sleeve 33 of the ultrasonic device 3 to reduce friction during rotation.

[0063] The extended length of the horn 36 is 40-60 mm, and the diameter is 3-5 mm.

[0064] The ultrasonic parameters are amplitude 0-20μm; frequency 20-50Hz, and static pressure 200-500N.

[0065] The bottom of the horn 36 is provided with three laser channels and three ball grooves, which are arranged in a circumference, and the first ball 43 is in contact with the hole wall 6 in an arc surface.

[0066] The first ball groove of the amplitude transformer 36 is arranged in one-to-one correspondence with the sleeve ball groove of the processing head 4, so that the ball groove of the amplitude transformer 36 and the sleeve ball groove of the processing head 4 cooperate to generate radial force, so that the first ball 43 vibrates radially; the diameter of the first ball 43 is 1-2mm.

[0067] According to a further optimization scheme, a plurality of ball grooves are provided at the connection between the amplitude changing rod 36 and the processing head housing 41 , and the ball grooves are arranged in a one-to-one correspondence with the first balls 43 .

[0068] According to a further optimization scheme, through holes are respectively opened in the centers of the processing head housing 41, the amplitude transformer 36, and the ultrasonic main shaft 22 to provide a propagation channel for the pulsed laser 5, and the central axes of all the through holes are on the same central axis.

[0069] In a further optimized solution, the beam splitting reflector 42 is installed in an end of the through hole of the processing head housing 41 away from the amplitude transformer 36 .

[0070] A further optimized solution is that the rotating device 2 includes a hollow conductive slip ring chamber 29 sleeved on the ultrasonic main shaft 22, the hollow conductive slip ring chamber 29 is detachably connected to the ultrasonic transducer 31, and a worm gear housing 28 and a worm housing 23 are provided at one end of the hollow conductive slip ring chamber 29 away from the ultrasonic transducer 31, a worm gear 27 is rotatably connected in the worm gear housing 28, the worm gear 27 is installed on the ultrasonic main shaft 22, the worm gear 27 is meshed with a worm 26, the worm 26 is rotatably connected in the worm housing 23, and one end of the worm bearing 25 of the worm 26 extending out of the worm housing 23 is transmission-connected to the second drive motor 21.

[0071] The ultrasonic main shaft 22 is rotatably connected to the worm gear housing 28 via a main shaft bearing 24 .

[0072] The second driving motor 21 drives the worm 26 to rotate through the coupling, and the worm 26 drives the worm wheel 27 to rotate. The ultrasonic main shaft 22 rotates synchronously with the worm wheel 27 through a key connection.

[0073] The rotating device 2 is a turbine worm rotating platform, which provides a propagation channel for the pulse laser 5 through the ultrasonic main shaft 22, the hollow conductive slip ring 293, the ultrasonic transducer 31 and the through hole in the axial center of the horn 36; the worm housing 28 is fixedly connected with the housing connection 291, the ultrasonic main shaft 22 is tensioned with the hexagon socket bolt 311, the hollow conductive slip ring 293 is installed in the hollow conductive slip ring chamber 29, and the hollow conductive slip ring 293 is arranged above the ultrasonic transducer 31, the lead wire at the stator end of the slip ring is connected to the power interface on the protective cover 292, and the lead wire at the rotor end of the slip ring is connected to the ultrasonic transducer 31.

[0074] The rotating device 2 can drive the ultrasonic main shaft 22, the rotor end of the hollow conductive slip ring 293, the ultrasonic transducer 31 and the rotating base 32, the horn 36, and the processing head 4 to rotate synchronously.

[0075] A further optimized solution is that the telescopic device 1 includes a lead screw 14 arranged below the worm housing 23, the lead screw 14 is threadedly connected to a nut seat 15, the top surface of the nut seat 15 is fixedly connected to the bottom surface of the worm housing 23, one end of the lead screw 14 is rotatably connected to a support seat 17, and the other end of the lead screw 14 is rotatably connected to a screw fixer 13.

[0076] The relationship between the feeding speed V of the telescopic device 1 and the laser impact frequency f, the spot diameter r and the overlap rate η is: V=f·r·η.

[0077] The relationship between the ultrasonic main shaft rotation speed N of the rotating device 2 and the laser impact frequency f is: N=60·f.

[0078] The workpiece with the hole to be strengthened is clamped and rotated by a three-jaw chuck. The rotation speed N0 is related to the radius R of the hole to be strengthened and the overlap rate η: N0 = (f·r·η·R) / 2π.

[0079] The telescopic device 1 is a double-line rail first ball screw linear platform. The telescopic device 1 is driven by a first drive motor 11 . The worm housing 23 is installed on the nut seat 15 and the slider 16 through internal screw connection.

[0080] A second ball is provided on the inner ring of the ultrasonic device support seat 171 to facilitate the sliding of the ultrasonic device 3 in the ultrasonic device support seat 171; the ultrasonic device support seat 171 can be tightened by bolts, on the one hand to prevent the ultrasonic device 3 from vibrating and causing position displacement during operation, and on the other hand to provide support for the ultrasonic device 3 when processing holes of different depths.

[0081] According to a further optimized solution, the support seat 17 includes a screw support seat 172 rotatably connected to the lead screw 14 , the top surface of the screw support seat 172 is fixedly connected to an ultrasonic device support seat 171 , and the ultrasonic device support seat 171 is slidably connected to the ultrasonic device 3 .

[0082] Guide rails 18 are symmetrically arranged on both sides of the lead screw 14, and a slider 16 is slidably connected to the guide rails 18. The slider 16 is fixedly connected to the bottom of the worm housing 23, and the two ends of the opposite sides of the base of the two guide rails 18 are fixedly connected to the screw fixer 13 and the screw support seat 172 respectively.

[0083] The rotation speed of the first drive motor 11 is set, and the rotational motion of the first drive motor 11 is converted into the rotational motion of the screw 14 through the coupling 12. The nut seat 15 moves along the axis of the screw 14 to convert the rotational motion into a linear motion along the guide rail 18, and the rotating device 2, the ultrasonic device 3 and the processing head 4 can perform linear telescopic motion; according to different processing scenarios, the base of the guide rail 18 can be installed on platforms with different angles, preferably a horizontal workbench; according to different processing hole materials, a feed speed of 0.1-2mm / s can be selected, and the effective moving distance is 0-80mm. According to the extended length of the amplitude rod 36, the processing enhancement of deep holes with an effective depth of 0-60mm can be met.

[0084] Working process:

[0085] According to the diameter and depth of the hole to be strengthened, a copper tube slightly smaller than the hole is selected, a layer of engine oil is applied on the copper tube, an energy absorption layer film composed of black paint is wrapped on the copper tube, and then the copper tube is inserted into the hole. After the copper tube is heated and expanded, the film is attached to the hole wall 6, and the copper tube is pulled out after cooling, thus forming an energy absorption layer on the hole wall 6; the energy absorption layer is composed of a flexible film of black paint with a thickness of 70-90μm, and an external water spray pipe is required to spray a weak water flow into the hole to form a constraint layer.

[0086] The rotating device 2 drives the ultrasonic transducer 31, the amplitude rod 36 and the processing head 4 to rotate synchronously through the ultrasonic main shaft 22, and the laser shock wave 7 and the ultrasonic shock wave 8 drive the first ball 43 to form an ultrasonic rolling alternating effect, and the telescopic device 1 completes the depth direction feeding, thereby realizing the composite processing strengthening of the laser shock wave 7 and the first ball 43 on the inner wall of the hole, and combining the ultrasonic shock wave 8 and the laser shock wave 7; through the composite effect of the laser shock wave 7 and the ultrasonic shock wave 8, high-density dislocations and a large number of nanocrystals are induced, and high-amplitude residual compressive stress and microhardness are introduced, thereby improving the stress intensity factor, effectively reducing the fatigue crack growth rate, and thus greatly improving the strength, wear resistance and fatigue performance.

[0087] When in use, aim the pulse laser 5 at the through hole at the axial center of the ultrasonic main shaft 22, the ultrasonic transducer 31 and the amplitude transformer 36. The pulse laser 5 is first divided into three beams of laser light by a beam splitting reflector 42. The angle between each two beams of laser light is 120°. The three beams of light form a 90° reflection with the inner wall of the aperture and are then focused on the surface of the hole wall 6 by a focusing mirror 44.

[0088] At the same time, during processing, an external water spray pipe is required to spray water into the hole. The water forms a water film on the inner surface of the hole, that is, a constraint layer, which can ensure that the inner wall surface is covered by the water flow, thereby realizing the constraint of the pressure of the laser shock wave 7 and the lubrication of the first ball 43.

[0089] When the processing head 4 works at the set rotation direction 9 and speed, the laser and the ultrasound act alternately, and the laser shock induces a shock wave with an ultra-high peak pressure and a short action time, so that the material produces a high-density dislocation structure and a residual compressive stress field with a deep influence layer under ultra-high strain rate conditions; the ultrasonic shock induces a shock wave with a high peak pressure and a long action time, which can improve the surface morphology, greatly reduce the surface roughness of the material, and produce a significantly refined grain structure with high microstructure stability and high residual compressive stress amplitude; the processing head 4 rotates, and the laser shock wave 7 and the ultrasonic shock wave 8 act alternately to achieve a composite; the composite effect of the laser shock wave 7 and the ultrasonic shock wave 8 increases the amplitude of the hardened layer and the residual compressive stress field and the depth of the influence layer, greatly increases the dislocation density and structural complexity inside the material, and at the same time promotes the dynamic recrystallization process to form a deeper nanocrystalline layer, thereby improving the wear resistance, corrosion resistance and fatigue strength of the millimeter-level slender hole.

[0090] The present invention integrates the gain effects of laser shock strengthening and ultrasonic rolling strengthening, so that the surface of the strengthened inner hole wall 6 obtains a deeper influence layer depth, a larger and more uniform residual compressive stress, the surface layer grains will be further refined, and its wear resistance, corrosion resistance and fatigue resistance are further improved.

[0091] Compared with the traditional laser shock peening process, the present invention causes the metal on the surface of the inner hole wall to produce plastic flow under the strong constraint of the first ball 43, thereby filling the depression or wavy morphology formed during the laser shock peening process, effectively reducing the roughness of the inner hole surface, and significantly improving its surface quality.

[0092] The present invention adopts the rotating device 2 to improve the circumferential arrangement, efficiency and precision of the laser and the first ball 43.

[0093] The present invention can process and strengthen the slender hole wall 6 with a diameter of 5.3-15.0 mm and a depth of 0-60 mm, thereby improving the use performance of the inner wall of the millimeter-level hole diameter.

[0094] Embodiment 2

[0095] Taking a titanium alloy plate with a hole diameter of 8mm and a depth of 20mm as an example, the working process is as follows:

[0096] A titanium alloy plate with a hole diameter of 8 mm and a depth of 20 mm was mounted on a three-jaw chuck and the parameters were set to rotate.

[0097] The first ball 43 of the processing head 4 is placed close to the inner wall of the hole, the power supply is connected to the stator end of the hollow conductive slip ring 293 through the interface of the protective cover 292, the ultrasonic transducer 31 is connected to the rotor end of the conductive slip ring through the power-connecting copper sheet 314, and the ultrasonic transducer 31 converts electrical energy into mechanical energy; the vibration wave is amplified in amplitude by the amplitude transformer 36 and transmitted to the inner wall surface of the hole through the first ball 43, and the amplitude transformer 36 and the ball groove of the processing head 4 limit the first ball 43 to radial vibration.

[0098] According to the diameter and depth of the hole to be strengthened, a copper tube slightly smaller than the hole is selected, a layer of engine oil is applied to the copper tube, and an energy absorption layer film composed of black paint is wrapped on the copper tube. Then, the copper tube is inserted into the hole, and the copper tube is heated. After the copper tube expands due to the heat, the film is attached to the hole wall 6, and the copper tube is pulled out after cooling. An external water spray pipe sprays a weak water flow into the hole to form a water film on the hole wall 6, forming a constraint layer to lubricate the first ball 43.

[0099] The laser is turned on, and the pulsed laser 5 passes through the through hole in the axial center of the ultrasonic main shaft 22, the ultrasonic transducer 31, and the amplitude transformer 36, and is divided into three laser beams and refracted by the beam splitting reflector 42, forming a 90° angle with the inner wall surface of the hole, and finally focused by the focusing mirror 44 on the inner wall surface of the hole for laser shock strengthening.

[0100] The speeds of the first drive motor 11 and the second drive motor 21 are set, the telescopic device 1 and the rotating device 2 are started, and the parameters are set. The ultrasonic spindle 22 drives the ultrasonic transducer 31, the amplitude rod 36, and the processing head 4 to rotate synchronously along the rotation direction 9. The first ball 43 and the focused laser beam act alternately on the inner wall surface of the hole to achieve composite strengthening of the ultrasonic shock wave 8 and the laser shock wave 7, and prepare the inner wall of the hole with an ultrafine grain surface.

[0101] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0102] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. An ultrasonic laser composite machining head for millimeter-level apertures, characterized in that: The invention comprises a processing head (4) for performing ultrasonic laser composite processing on a micro hole, wherein a beam splitting reflector (42) for beam splitting a pulse laser (5) is arranged inside the processing head (4), an ultrasonic device (3) for transmitting an ultrasonic shock wave (8) to the processing head (4) is arranged at one end of the processing head (4) extending outside the micro hole, a rotating device (2) for driving the processing head (4) to rotate is arranged at one end of the ultrasonic device (3) away from the processing head (4), a telescopic device (1) for driving the rotating device (2) to move horizontally is arranged at the bottom of the rotating device (2), and a support seat (17) is slidably connected to one end of the ultrasonic device (3) away from the rotating device (2), and the support seat (17) is fixedly connected to the telescopic device (1).

2. The ultrasonic laser composite machining head for millimeter-level aperture according to claim 1, characterized in that: The processing head (4) comprises a processing head shell (41) detachably connected to the ultrasonic device (3); the beam splitting reflector (42) is arranged in one end of the processing head shell (41) away from the ultrasonic device (3); each reflection surface of the beam splitting reflector (42) is respectively provided with a corresponding protective mirror (45) through a focusing mirror (44); the protective mirror (45) penetrates the outer wall of the processing head shell (41) and is embedded in the outer wall of the processing head shell (41).

3. The ultrasonic laser composite machining head for millimeter-level aperture according to claim 2, characterized in that: A first ball (43) is respectively arranged between two adjacent protective mirrors (45); the first ball (43) passes through the processing head shell (41) and extends out of the processing head shell (41); and the portion of the first ball (43) extending into the processing head shell (41) is arranged in the ultrasonic device (3).

4. The ultrasonic laser composite machining head for millimeter-level aperture according to claim 3, characterized in that: The ultrasonic device (3) comprises a variable amplitude rod (36) threadedly connected to and communicated with the machining head housing (41); one end of the variable amplitude rod (36) away from the machining head housing (41) is connected to an ultrasonic main shaft (22) through an ultrasonic transducer (31); and the ultrasonic main shaft (22) passes through the rotating device (2).

5. The ultrasonic laser composite machining head for millimeter-level aperture according to claim 4, characterized in that: A plurality of ball grooves are provided at the connection between the amplitude changing rod (36) and the processing head housing (41), and the ball grooves are arranged in one-to-one correspondence with the first balls (43).

6. The ultrasonic laser composite machining head for millimeter-level aperture according to claim 4, characterized in that: Through holes for providing a propagation channel for the pulsed laser (5) are respectively formed at the centers of the machining head housing (41), the horn (36), and the ultrasonic main shaft (22), and the central axes of all the through holes are on the same central axis.

7. The ultrasonic laser composite machining head for millimeter-level aperture according to claim 6, characterized in that: The beam splitting reflector (42) is installed in an end of the through hole of the processing head housing (41) away from the amplitude changing rod (36).

8. The ultrasonic laser composite machining head for millimeter-level aperture according to claim 4, characterized in that: The rotating device (2) comprises a hollow conductive slip ring chamber (29) sleeved on the ultrasonic main shaft (22), the hollow conductive slip ring chamber (29) being detachably connected to the ultrasonic transducer (31), a worm gear housing (28) and a worm housing (23) being arranged at one end of the hollow conductive slip ring chamber (29) away from the ultrasonic transducer (31), a worm gear (27) being rotatably connected inside the worm gear housing (28), the worm gear (27) being mounted on the ultrasonic main shaft (22), a worm gear (26) being meshed with the worm gear (27), the worm gear (26) being rotatably connected inside the worm housing (23), and a second drive motor (21) being transmission-connected to one end of a worm bearing (25) of the worm gear (26) extending outside the worm housing (23).

9. The ultrasonic laser composite machining head for millimeter-level aperture according to claim 8, characterized in that: The telescopic device (1) comprises a lead screw (14) arranged below the worm housing (23); the lead screw (14) is threadedly connected to a nut seat (15); the top surface of the nut seat (15) is fixedly connected to the bottom surface of the worm housing (23); one end of the lead screw (14) is rotatably connected to the support seat (17); and the other end of the lead screw (14) is rotatably connected to a screw fixer (13).

10. The ultrasonic laser composite machining head for millimeter-level aperture according to claim 9, characterized in that: The support seat (17) comprises a screw support seat (172) rotatably connected to the lead screw (14); the top surface of the screw support seat (172) is fixedly connected to an ultrasonic device support seat (171); and the ultrasonic device support seat (171) is slidably connected to the ultrasonic device (3).

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