Millimeter-scale aperture ultrasonic laser composite machining head

Abstract

The present application relates to the technical fields of ultrasonic laser compound machining, in particular to a kind of millimeter aperture ultrasonic laser compound machining head, including the machining head for being used to carry out ultrasonic laser compound machining to micro-hole, the beam splitter mirror for being used to carry out beam splitting to pulse laser is arranged in machining head, the end of machining head that projects outside micro-hole is provided with the ultrasonic device for transmitting ultrasonic shock wave to machining head, the end of ultrasonic device away from machining head is provided with the rotating device for driving machining head to rotate, the bottom of rotating device is provided with the telescopic device for driving rotating device horizontal reciprocating movement, the end of ultrasonic device away from rotating device is slidably connected with support seat, support seat is fixedly connected with telescopic device.The present application makes machining head can carry out the compound machining of pulse laser and ultrasonic to micro-hole, makes the compound machining of pulse laser and ultrasonic can effectively strengthen the aperture inner wall surface of millimeter micro-hole, improve the wear resistance and corrosion resistance of millimeter micro-hole.

Description

Technical Field

[0001] The present 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, and directly affect 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, millimeter-level apertures will wear due to friction during use. Under frequent loading and unloading conditions, the material around the aperture may suffer fatigue damage. In harsh environments, it may be affected by corrosion. These effects will lead to deterioration of millimeter-level aperture accuracy, cracks and fractures, and deterioration of 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 micro-holes, 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 objectives, the present invention provides the following solution: 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 the pulsed laser is provided in the processing head, an ultrasonic device for transmitting ultrasonic shock waves to the processing head is provided at one end of the processing head extending outside the microhole, a rotating device for driving the processing head to rotate is provided at one end of the ultrasonic device away from the processing head, a telescopic device for driving the rotating device to move horizontally back and forth is provided at the bottom of the rotating device, and a support seat is slidably connected to the 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 in an end of the processing head shell away from the ultrasonic device, and 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 provided 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 provided in the ultrasonic device.

[0007] Preferably, the ultrasonic device includes a horn threadedly connected to and communicated with the machining head housing, one end of the horn away from the machining head housing is connected to an ultrasonic main shaft through an ultrasonic transducer, and the ultrasonic main shaft 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 a one-to-one correspondence with the first balls.

[0009] Preferably, the centers of the machining head housing, the amplitude transformer, and the ultrasonic main shaft are respectively provided with through holes that provide propagation channels for the pulsed laser, 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 changing rod.

[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, and 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 engaged with a worm, and the worm is rotatably connected in the worm housing, and the 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 screw arranged below the worm housing, the 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 screw is rotatably connected to the support seat, and the other end of the screw is rotatably connected to a screw fixer.

[0013] Preferably, the support seat includes 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 microholes, so that the pulse laser and ultrasonic composite processing can effectively strengthen the inner wall surface of the millimeter-level microholes, improve the wear resistance and corrosion resistance of the millimeter-level microholes, and extend the service life of the millimeter-level microholes. 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 following briefly introduces the drawings required for use in the embodiments. 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 any creative work.

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

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

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

[0020] Figure 4 Schematic diagram of the structure of the ultrasonic device of the present invention;

[0021] Figure 5 This is a schematic cross-sectional view of the ultrasonic device of the present invention;

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

[0023] Figure 7 This is a schematic diagram of the top view 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] Figure 9 This is the pulse laser optical path diagram of the present invention;

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

[0027] Figure 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 holder; 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 gear; 28. worm gear housing; 29. ​​hollow conductive slip ring chamber; 291. housing connection; 292. protective sleeve; 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. Fixed 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 mirror; 45. Protective mirror; 5. Pulsed laser; 6. Hole wall; 7. Laser shock wave; 8. Ultrasonic shock wave; 9. Direction of rotation. 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 laser 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 impact of laser and ultrasound combined 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 within the material, lowering 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, thereby improving the quality of the weld joint.

[0037] Tissue homogeneity: The application 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 peening uses laser pulses to generate high-energy shock waves on the metal surface, implanting higher microhardness and residual compressive stress on the material surface and refining the material surface grains to a greater extent. It 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 deep residual stress layer inside the pipe, changing 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, it 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 apparatus and method for ultrasonic-assisted laser shot peening composite strengthening. This patent effectively realizes the combination of laser shock waves and ultrasonic shock waves, promotes the dynamic recrystallization behavior of the material, and prepares metal parts with ultrafine grain surfaces.

[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 for laser shock waves and ultrasonic shock waves, 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 clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. 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 making creative efforts 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] Example 1

[0049] Reference Figures 1-11 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 pulsed laser 5 is provided in the processing head 4, an ultrasonic device 3 for transmitting an ultrasonic shock wave 8 to the processing head 4 is provided 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 provided at the 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 provided at the bottom of the rotating device 2, and a support seat 17 is slidably connected to the 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 micropores, so that the pulse laser 5 and ultrasonic composite processing can effectively strengthen the inner wall surface of the millimeter-level micropores, improve the wear resistance and corrosion resistance of the millimeter-level micropores, and extend the service life of the millimeter-level micropores.

[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 operates 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 at the same time, 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 that is detachably connected to the ultrasonic device 3, and a beam splitting reflector 42 is arranged in an end of the processing head shell 41 away from the ultrasonic device 3. 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 with a three-claw pressure arm. The pulse laser 5 passes through the through hole of the processing head 4 and is divided into three beams by the beam splitting reflector 42 and refracted. The angle between each 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 mirror 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 is a sharp edge between the three right-angled surfaces, and the edges are not chamfered. The pulsed laser 5 directly incident on the sharp edge is split into three laser beams. The optical path is deflected 90°, and the angle between each two laser beams is 120°; the three right-angled surfaces are coated with a gold-plated high-reflective film with a reflectivity Ravg>95%; the damage threshold is:>1J / cm2, 20ns, 20Hz, @1064nm.

[0057] As a further optimization solution, a first ball 43 is respectively provided 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 provided in the ultrasonic device 3 .

[0058] In a further optimized solution, the ultrasonic device 3 includes a variable amplitude rod 36 threadedly connected to 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 in length and 60 mm in diameter.

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

[0061] The ultrasonic device 3 is fixed to the bottom of the protective sleeve 294, i.e., below the hollow conductive slip ring chamber 29, via a screw 34. When powered, the ultrasonic transducer 31 converts electrical energy into mechanical energy to generate ultrasonic waves. The mechanical amplitude of the ultrasonic waves is amplified by the horn 36, and the amplitude is transmitted to the first ball 43 in the machining head 4, causing it to vibrate.

[0062] One end of the horn 36 is installed in the ultrasonic device fixing sleeve 33, 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] Ultrasonic parameters are amplitude 0-20 μm; frequency 20-50 Hz, 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 circumferential manner, 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 a 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, causing the first ball 43 to vibrate radially; the diameter of the first ball 43 is 1-2 mm.

[0067] As a further optimization solution, 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 provided in a one-to-one correspondence with the first balls 43 .

[0068] As a further optimization solution, through holes are respectively opened in the centers of the machining head housing 41 , the amplitude transformer 36 , and the ultrasonic main shaft 22 to provide propagation channels 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 the end of the through hole of the machining head housing 41 away from the horn 36 .

[0070] A further optimized solution is provided, in which the rotating device 2 includes a hollow conductive slip ring chamber 29 sleeved on the ultrasonic main shaft 22, and the hollow conductive slip ring chamber 29 is detachably connected to the ultrasonic transducer 31. 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, and the worm gear 27 is mounted on the ultrasonic main shaft 22. The worm gear 27 is engaged with a worm 26, and the worm 26 is rotatably connected in the worm housing 23. The worm bearing 25 of the worm 26 extends out of the worm housing 23 and 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 drive 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 through hole in the axial center of the ultrasonic main shaft 22, the hollow conductive slip ring 293, the ultrasonic transducer 31 and the horn 36; the worm housing 28 is fixedly connected to the housing connection 291, the ultrasonic main shaft 22 is expansion-connected 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 at the stator end of the slip ring is connected to the power interface on the protective cover 292, and the lead 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 screw 14 arranged below the worm housing 23, the 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 screw 14 is rotatably connected to the support seat 17, and the other end of the screw 14 is rotatably connected to the screw fixer 13.

[0076] The relationship between the feed 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 shock 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-track first ball screw linear platform. The telescopic device 1 is driven by a first drive motor 11 . The worm housing 23 is internally screwed and mounted on the nut seat 15 and the slider 16 .

[0080] A second ball bearing 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 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 side 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 rotational speed of the first drive motor 11 is set, and the coupling 12 converts the rotational motion of the first drive motor 11 into the rotational motion of the lead screw 14. The nut holder 15 moves along the axis of the lead screw 14, converting the rotational motion into linear motion along the guide rail 18. This allows the rotating device 2, ultrasonic device 3, and machining head 4 to perform linear telescopic motion. Depending on the machining scenario, the base of the guide rail 18 can be mounted on platforms at different angles, preferably a horizontal workbench. Depending on the material being machined, a feed rate of 0.1-2 mm / s and an effective travel distance of 0-80 mm can be selected. Depending on the extended length of the horn 36, deep hole machining with an effective depth of 0-60 mm can be enhanced.

[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, 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. After the copper tube is heated and expanded, the film is attached to the hole wall 6. After the copper tube is cooled, it is pulled out, and an energy absorption layer is formed on the hole wall 6. The energy absorption layer is composed of a flexible film of black paint with a thickness of 70-90μm. 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. The laser shock wave 7 and the ultrasonic shock wave 8 drive the first ball 43 to form an alternating ultrasonic rolling action. 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, 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, the pulsed laser 5 is aligned with the through hole at the axial center of the ultrasonic main shaft 22, the ultrasonic transducer 31 and the amplitude transformer 36. The pulsed laser 5 is first divided into three beams of laser light by the 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 then are focused on the surface of the hole wall 6 by the 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 ultra-high peak pressure and short action time, so that the material produces a high-density dislocation structure and a residual compressive stress field with a deep affected layer under ultra-high strain rate conditions; the ultrasonic shock induces a shock wave with high peak pressure and 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 affected 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 holes.

[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, larger and more uniform residual compressive stress, the surface layer grains will be further refined, and its wear resistance, corrosion resistance and fatigue resistance will be 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 wall 6 of an elongated hole with a diameter of 5.3-15.0 mm and a depth of 0-60 mm, thereby improving the performance of the inner wall of a millimeter-level hole.

[0094] Example 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 copper sheet 314. 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. The amplitude transformer 36 and the ball groove of the processing head 4 limit the first ball 43 to radial vibration.

[0098] Based on the diameter and depth of the hole to be strengthened, a copper tube slightly smaller than the hole is selected. A layer of motor oil is applied to the copper tube, and a black paint energy-absorbing film is applied to the copper tube. The copper tube is then inserted into the hole and heated. After the heat expands, the film adheres to the hole wall 6. The copper tube is then removed after cooling. An external water spray pipe sprays a weak stream of water into the hole, forming a water film on the hole wall 6, forming a constraining 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 by the beam splitting reflector 42 and refracted, forming a 90° angle with the inner wall surface of the hole. Finally, it is focused by the focusing mirror 44 and acts on the inner wall surface of the hole to perform laser shock peening.

[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", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0102] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. An ultrasonic laser composite machining head for millimeter-level apertures, characterized by: The invention comprises a processing head (4) for performing ultrasonic laser composite processing on a microhole, wherein a beam splitting reflector (42) for splitting a pulse laser (5) is provided in the processing head (4), an ultrasonic device (3) for transmitting an ultrasonic shock wave (8) to the processing head (4) is provided at one end of the processing head (4) extending outside the microhole, a rotating device (2) for driving the processing head (4) to rotate is provided 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 provided at the bottom of the rotating device (2), and a support seat (17) is slidably connected to the 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); 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 reflecting surface of the beam splitting reflector (42) is respectively provided with a protective mirror (45) via 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); A first ball (43) is respectively provided between two adjacent protective mirrors (45), the first ball (43) passing through the processing head housing (41) and extending outside the processing head housing (41), and the portion of the first ball (43) extending into the processing head housing (41) is provided in the ultrasonic device (3); The ultrasonic device (3) comprises a horn (36) threadedly connected to and in communication with the machining head housing (41); one end of the horn (36) away from the machining head housing (41) is in communication with an ultrasonic main shaft (22) via an ultrasonic transducer (31); and the ultrasonic main shaft (22) passes through the rotating device (2); 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); The centers of the machining head housing (41), the horn (36), and the ultrasonic main shaft (22) are respectively provided with through holes that provide propagation channels for the pulsed laser (5), and the central axes of all the through holes are on the same central axis; 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) and is divided into three beams by the beam splitting reflector (42) and refracted. The angle between each two laser beams is 120°, and the refracted pulse laser forms a 90° angle with the inner wall of the hole; the three focusing mirrors (44) are arranged on the circumference of the inner boss of the processing head (4) to focus the refracted pulse laser; the three protective mirrors (45) and the three first balls (43) are arranged on the circumference of the processing head (4).

2. The ultrasonic laser composite machining head for millimeter-level aperture according to claim 1, 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).

3. The ultrasonic laser composite machining head for millimeter-level aperture according to claim 1, characterized in 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) being detachably connected to the ultrasonic transducer (31), a worm gear housing (28) and a worm housing (23) being provided at one end of the hollow conductive slip ring chamber (29) away from the ultrasonic transducer (31), a worm gear (27) being rotatably connected in the worm gear housing (28), the worm gear (27) being mounted on the ultrasonic main shaft (22), the worm gear (27) being meshed with a worm (26), the worm (26) being rotatably connected in the worm housing (23), and an end of a worm bearing (25) of the worm gear (26) extending outside the worm housing (23) being transmission-connected to a second drive motor (21).

4. The ultrasonic laser composite machining head for millimeter-level aperture according to claim 3, characterized in that: The telescopic device (1) includes a lead screw (14) arranged below the worm housing (23), the lead screw (14) being threadedly connected to a nut seat (15), the top surface of the nut seat (15) being fixedly connected to the bottom surface of the worm housing (23), one end of the lead screw (14) being rotatably connected to the support seat (17), and the other end of the lead screw (14) being rotatably connected to a screw fixer (13).

5. The ultrasonic laser composite machining head for millimeter-level aperture according to claim 4, characterized in that: 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).

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