Ceramic-based composite material connecting hole ultrasonic / water-jet guided laser combined machining device

Abstract

The invention relates to a ceramic-based composite material connecting hole ultrasonic / water-guided laser combined machining device, in particular to a ceramic-based composite material hole characteristic water-guided laser and ultrasonic-assisted vibration combined machining device which is used for machining connection holes, special-shaped holes and butt joint boundaries of material fasteners such as ceramic-based composite materials / high-temperature alloy in aircraft assembly. Belongs to the field of aeronautical manufacturing engineering / aircraft assembly. And the requirement for high-precision and rapid machining of the thermal adaptation connecting holes of ceramic material flat-plate type (or near-flat-plate) small parts is met. A combined machining mode is adopted, the advantages of ultrasonic-assisted vibration and water-guided laser are fully played, machining modes are convenient to convert, the machining difficulty of high-hardness and high-brittleness materials is remarkably reduced, meanwhile, the defects that laser machining aperture precision is not high, and a heat affected zone exists are overcome, the machining efficiency and precision are both considered, parts are clamped and positioned at a time, and machining precision is high. And assembly in-situ machining of various types of connecting holes can be completed.

Description

Technical Field

[0001] This invention relates to a composite processing device for water-guided laser and ultrasonic-assisted vibration for machining the hole characteristics of ceramic matrix composites. It is used for machining fastener connection holes, irregular holes and seam boundaries of ceramic matrix composites / high temperature alloys and other materials in aircraft assembly, and belongs to the field of aerospace manufacturing engineering / aircraft assembly. Background Technology

[0002] High-temperature resistant materials such as ceramic composites, high-temperature alloys, and refractory metals are all difficult to machine. For example, ceramic matrix composites such as SiC / SiC and C / SiC have high hardness but low toughness, and conventional machining processes are prone to problems such as excessive cutting forces, poor surface quality, and severe machining damage. In addition, high-speed aircraft have complex shapes, and considering the requirements of thermal deformation compensation and structural-functional integration, there are a large number of irregular holes (such as elongated holes, grid array holes, etc.), which poses greater challenges to the aircraft assembly site. There is an urgent need to develop rapid and precise hole making and trimming technologies for difficult-to-machine materials that are suitable for the assembly site.

[0003] Conventional machining methods suffer from severe tool wear, low processing efficiency, and poor quality, specifically manifested as poor dimensional consistency, surface cracks, breakage, delamination, fiber debonding, fiber pull-out, and edge chipping, severely impacting processing quality and material surface precision. To meet the processing needs of hard and brittle materials, various specialized machining methods such as laser processing, electrical discharge machining, high-pressure water jet machining, ion beam machining, and ultrasonic machining have emerged and developed significantly in recent years. Laser processing involves high temperatures, essentially vaporizing the material in the cutting area. In laser processing, ceramic materials are prone to damage due to excessive heat accumulation; therefore, continuous laser processing is unsuitable for ceramic matrix composites. Domestic and international research indicates that ultrashort pulse laser processing of SiC / SiC composites for micro-through holes and blind holes can efficiently achieve hole processing accuracy and wall quality within a certain thickness range. However, with excessive thickness, the laser focal length can affect the formation of tapered holes, impacting processing accuracy. Water-guided lasers are an emerging technology with processing efficiency close to pulsed lasers. They offer good hole diameter consistency in thick plate processing, with minimal variation in hole diameter between the inlet and outlet sides, making them suitable for deep hole processing. Ultrasonic-assisted grinding is considered one of the most promising methods for efficient and precise machining of hard and brittle materials. It involves high-frequency axial ultrasonic vibration accompanying the high-speed rotation of the grinding wheel. Compared to conventional grinding methods, ultrasonic-assisted grinding offers advantages such as reduced cutting forces, less machining damage, improved machining efficiency and accuracy, and extended tool life. Compared to ultrasonic-assisted vibration machining, water-guided laser machining is more efficient and eliminates tool wear issues. However, laser machining introduces a heat-affected zone to varying degrees, impacting the fatigue strength of the joint. Furthermore, the precision of water-guided laser machining is lower than that of ultrasonic-assisted vibration machining. Summary of the Invention

[0004] The ceramic matrix composite ultrasonic vibration-assisted grinding and water-guided laser composite processing device proposed in this invention fully utilizes the advantages of ultrasonic-assisted vibration and water-guided laser. For processing tasks with low precision requirements and insensitivity to heat-affected zones, the water-guided laser processing mode is adopted, which significantly reduces the processing difficulty. For fine processing or removal of heat-affected zones, ultrasonic-assisted vibration grinding is adopted, which solves the contradiction between processing efficiency and processing precision.

[0005] According to one aspect of this application, an apparatus for ultrasonic / water-guided laser composite processing of connecting holes in ceramic matrix composites is provided, comprising a base frame 1, a processing system 2, a transmission system 3, and a workpiece clamping platform 4.

[0006] The basic frame 1 includes a device base 11, a Y-axis moving slide 12, an X-axis moving slide 13, and a Z-axis feed slide 14;

[0007] The processing system 2 includes a water-guided laser processing unit 21 and an ultrasonic-assisted vibration processing unit 22;

[0008] The transmission system includes an X-axis actuation unit 31, a Y-axis actuation unit 32, and a Z-axis feed unit 33.

[0009] The basic frame 1 is the basic structure of the composite processing device and is required to have sufficient rigidity.

[0010] The device is fixed to the ground by the equipment base 11, and the Y-axis movable slide 12 provides a mounting carrier for the workpiece and has a Y-axis degree of freedom;

[0011] The X-axis movable slide 13 provides installation space for the device and has the X-axis degree of freedom of movement;

[0012] The Z-axis feed slide 14 provides a mounting base for the ultrasonic-assisted vibration machining unit 22 and has x-axis feed freedom.

[0013] The ultrasonic-assisted vibration machining unit 22 mainly consists of an electric spindle 221, an ultrasonic tool holder 222, and a machining tool 223.

[0014] Water-guided laser processing removes material layer by layer through ablation, unaffected by material hardness or strength. Therefore, it can perform high-precision machining of ceramic materials and enable online machining of high-hardness and brittle materials. However, the laser ablation process creates a heat-affected zone, limiting its application in stress-sensitive and high-load structures. A combined approach of water-guided laser and ultrasonic-assisted vibration machining can be used. The water-guided laser removes most of the material, improving processing efficiency, while ultrasonic-assisted vibration machining removes only the heat-affected zone (typically less than 0.1 mm), with minimal impact on tool life due to the small amount of material removed. Water-guided lasers guide a high-frequency pulsed laser beam into a high-pressure water column, achieving an effective machining depth variation of up to 50 mm, completely covering the thickness range of thermally adaptable structural materials. Therefore, water-guided laser processing does not require feed motion along the z-axis.

[0015] Ultrasonic-assisted vibration machining is similar to conventional mechanical grinding.

[0016] The main electric spindle 221 provides rotational power to drive the machining tool 223 to remove material, while the ultrasonic tool holder 222 provides high-frequency, low-amplitude vibration along the tool axis to the machining tool 223, which helps to reduce cutting force, improve tool life, and adapt to the machining of high-hardness and high-brittle materials.

[0017] The X-axis actuation unit 31, Y-axis actuation unit 32, and Z-axis feed unit 33 are installed perpendicularly to each other to form a three-axis drive system. Under the control of the motion control system, they perform interpolation motion and can complete machining feed equivalent to that of a three-axis machining tool.

[0018] The X-axis actuation unit 31 mainly includes a motor, coupling, ball screw, grating ruler, bearing seat, guide rail and slider, etc., and is used for the actuation and positioning of the X-axis moving slide 13. The mechanism movement adopts the grating ruler as a closed-loop control means, with a positioning accuracy of 0.01mm.

[0019] The motor, coupling, ball screw, grating ruler, bearing seat, guide rail, etc. in the X-axis actuation unit 31 are installed on the equipment base 11. The slider is fixed on the X-axis moving slide 13. The X-axis moving slide 13 has only X-axis degree of freedom through the cooperation of the slider and the guide rail, and the X-axis high-precision positioning of the processing system 2 is realized under closed-loop control.

[0020] The Y-axis actuation unit 32 mainly includes a motor, coupling, ball screw, grating ruler, bearing seat, guide rail and slider, etc., for the actuation and positioning of the Y-axis moving slide 12, realizing the position adjustment and processing feed of the workpiece. The mechanism movement adopts the grating ruler as a closed-loop control means, with a positioning accuracy of 0.01mm.

[0021] The motor, coupling, ball screw, grating ruler, bearing seat, guide rail, etc. in the Y-axis actuation unit 32 are installed on the equipment base 11. The slider is fixed on the Y-axis moving slide 12. The Y-axis moving slide 12 has only the Y-axis degree of freedom through the cooperation of the slider and the guide rail, and achieves high-precision positioning of the workpiece in the X-axis under closed-loop control.

[0022] The Z-axis feed unit 33 mainly includes a motor, coupling, ball screw, grating ruler, bearing seat, guide rail and slider, etc., for the operation and positioning of the Z-axis feed slide 14, realizing the feed of the ultrasonic assisted vibration processing unit 22 along the Z-axis. The mechanism motion adopts the grating ruler as a closed-loop control means, with a positioning accuracy of 0.01mm.

[0023] The motor, coupling, ball screw, grating ruler, bearing seat, guide rail, etc. in the Z-axis feed unit 33 are installed on the X-axis moving slide 13, and the slider is fixed on the Z-axis feed slide 14. The Z-axis feed slide 14 has only the Z-axis degree of freedom through the cooperation of the slider and the guide rail, and realizes the cutting feed of the ultrasonic assisted vibration machining unit 22 under closed-loop control.

[0024] The workpiece clamping platform 4 is used to install and clamp workpieces. Its lower surface is fixedly connected to the upper part of the Y-direction moving slide 12, and the upper surface is used to install the workpiece to be processed. It can adapt to the flexible clamping and fixing of parts with different shapes.

[0025] This invention provides a method for ultrasonic / water-guided laser composite machining of connection holes in ceramic matrix composites. Using the aforementioned device, which integrates ultrasonic-assisted vibration and water-guided laser machining technologies, it can complete the machining of connection features such as oblong holes, round holes, irregularly shaped holes, and stepped holes according to the requirements of thermally adaptable connection processes. Ceramic matrix composites (such as C / C, SiC / SiC, etc.) are high-hardness and high-brittle materials. Generally, connection holes and boundaries are mainly machined using water-guided laser machining. For fastener mounting holes with high requirements for hole diameter accuracy and heat-affected zone, ultrasonic-assisted vibration is used for precision machining and removal of the heat-affected zone, meeting differentiated processing needs and ensuring processing accuracy and efficiency.

[0026] Based on the aforementioned equipment and processing requirements, a composite machining process flow is formulated. First, based on the processing characteristics and part geometric parameters, the machining process design is carried out, a CNC machining program is compiled, and it is sent to the control system of the composite machining device. Machining preparation step: The part to be processed is fixedly installed on the workpiece clamping platform 4, and coordinate calibration is performed to unify the coordinate system of the composite machining device and the part. Water-guided laser machining step: Water-guided laser machining is used for initial processing. The water-guided laser machining unit 21 is started and runs according to the CNC machining program. For through holes, to reduce the workload, the machining path is the feature boundary, and the laser ablation amount per pass is generally no more than 0.1 mm. For thick plates, the machining follows the feature boundary cyclic movement until the machining is completed. For stepped holes or blind holes, the smaller diameter area is machined first, using the same method as for through holes. The stepped section is machined layer by layer in a ring-shaped area until the stepped surface is completed. The same applies to blind holes.

[0027] After the water-guided laser processing is completed, it is determined whether finishing or oxide layer removal is required. If so, the ultrasonic-assisted vibration processing unit 22 is activated to complete the processing. If not, it is determined whether the processing is complete. If not, the workpiece position is adjusted to proceed to the next processing cycle. If complete, the program is exited and the equipment is reset.

[0028] The advantages of this application are:

[0029] This invention proposes a composite machining device for ultrasonic vibration-assisted grinding and water-guided laser machining of ceramic matrix composites, which meets the requirements for high-precision and rapid machining of thermally adaptable connection holes in small flat (or near-flat) ceramic parts. Employing a composite machining method, it fully leverages the advantages of ultrasonic-assisted vibration and water-guided laser, facilitating convenient switching between machining modes and significantly reducing the machining difficulty of high-hardness and brittle materials. Simultaneously, it overcomes the drawbacks of laser machining, such as low hole diameter accuracy and the existence of a heat-affected zone, balancing machining efficiency and precision. Parts can be clamped and positioned in a single setup, enabling in-situ machining of various types of connection holes. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of a composite processing device;

[0031] in:

[0032] 1. Basic frame, 2. Machining system, 3. Transmission system, 4. Workpiece clamping platform, 11. Equipment base, 12. Y-axis moving slide, 13. X-axis moving slide, 14. Z-axis feed slide, 21. Water-guided laser machining unit, 22. Ultrasonic assisted vibration machining unit, 221. Electric spindle, 222. Ultrasonic tool holder, 223. Machining tool, 31. X-axis actuation unit, 32. Y-axis actuation unit, 33. Z-axis feed unit. Detailed Implementation

[0033] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0034] Example 1

[0035] The main body of the device of this invention comprises four parts: a basic frame 1, a processing system 2, a transmission system 3, and a workpiece clamping platform 4. Figure 1 As shown, it features both ultrasonic-assisted vibration and water-guided laser processing modes, which can be freely switched according to process requirements. The workpiece does not need to be repositioned after a single clamping, enabling high-precision and rapid processing of ceramic matrix composite parts. Some small parts, standard parts, cables, wiring channels, pipes, control systems, and control software are not shown.

[0036] The specific implementation method is as follows:

[0037] (1) The basic frame 1 includes a device base 11, a Y-axis moving slide 12, an X-axis moving slide 13, and a Z-axis feed slide 14, such as Figure 1 As shown. The entire device is fixed to the foundation by the equipment base 11. The Y-axis moving slide 12, the X-axis moving slide 13 and the Z-axis feed slide 14 provide installation space for the machining system 2 and the workpiece clamping platform 4.

[0038] (2) The transmission system 3 mainly consists of an X-axis actuation unit 31, a Y-axis actuation unit 32, and a Z-axis feed unit 33. The installation requirements are as follows:

[0039] 1) The X-axis actuation unit 31, the Y-axis actuation unit 32 and the Z-axis feed unit 33 are installed perpendicular to each other. Under the control of the equipment control system, they have interpolation motion function and can complete machining feed equivalent to a three-axis machining tool. The single-axis positioning accuracy is not less than 0.01mm and the motion space positioning accuracy is not less than 0.015mm.

[0040] 2) Install the motor, coupling, ball screw, grating ruler, bearing seat, guide rail, etc. in the X-axis actuation unit 31 at the corresponding positions on the equipment base 11, ensuring the parallelism of the two guide rails, and fasten the connection with bolts. Adjust the position of the slider to ensure smooth movement, and then fix it to the corresponding position of the X-axis moving slide 13 with bolts.

[0041] 3) Install the motor, coupling, ball screw, grating ruler, bearing housing, guide rail, etc. in the Y-axis actuation unit 32 at the corresponding positions on the equipment base 11, ensuring that the two guide rails are parallel and perpendicular to the guide rail of the X-axis actuation unit 31. Adjust the position of the slider to ensure smooth movement, and then fix it to the Y-axis moving slide plate 12 with bolts.

[0042] 4) Install the motor, coupling, ball screw, grating ruler, bearing housing, guide rail, etc. in the Z-axis feed unit 33 at the corresponding positions on the X-axis moving slide 13, ensuring that the two guide rails are parallel and perpendicular to the guide rails of the X-axis actuation unit 31 and the Y-axis actuation unit 32. Adjust the slider position to ensure smooth movement, and then fix it to the Z-axis feed slide 14 with bolts.

[0043] 5) Check the installation accuracy of the X-axis actuation unit 31, Y-axis actuation unit 32 and Z-axis feed unit 33, check the working status of the motor and grating ruler, and power on to test to ensure normal performance.

[0044] (3) The processing system 2 includes a water-guided laser processing unit 21 and an ultrasonic-assisted vibration processing unit 22. The installation requirements are as follows:

[0045] 1) Pre-install the water-guided laser processing unit 21 at the corresponding position of the X-direction moving slide 13, and adjust its position to ensure that the water column ejected by the water-guided laser processing unit 21 is perpendicular to the movement direction of the X-direction moving slide 13 and parallel to the movement direction of the Z-direction feed slide 14.

[0046] 2) The electric spindle 221 of the ultrasonic-assisted vibration machining unit 22 is pre-installed at the corresponding position of the Z-axis feed slide 14 and finely adjusted to ensure that the axis of the electric spindle 221 is parallel to the movement direction of the Z-axis feed slide 14. The ultrasonic tool holder 222 is installed at the corresponding position of the electric spindle 221, and the machining tool 223 is installed in the ultrasonic tool holder 222 with the aid of a tool and locked.

[0047] 3) After the water-guided laser processing unit 21 and the ultrasonic-assisted vibration processing unit 22 are installed, connect the cables and pipelines, check the equipment status, and power on to test to ensure normal performance.

[0048] (4) The lower surface of the workpiece clamping platform 4 is fixedly connected to the upper part of the Y-direction moving slide 12. The upper surface has a workpiece installation interface and can adapt to the flexible clamping and fixing of parts of different shapes.

[0049] (5) After the composite processing state is installed, joint debugging is carried out to ensure that all functions and indicators meet the usage requirements. After the system is verified to be reliable through process testing, it can be put into actual processing application.

[0050] (6) Composite processing flow: Based on processing requirements, a composite processing flow is formulated as follows:

[0051] 1) Based on the machining characteristics and part geometric parameters, design the machining process, compile the CNC machining program, and send it to the control system of the composite machining device.

[0052] 2) Machining preparation: Fix the part to be processed on the workpiece clamping platform 4 and perform coordinate calibration.

[0053] 3) Water-guided laser processing: Water-guided laser processing is used for initial processing. The water-guided laser processing unit 21 is started and runs according to the CNC machining program. For through holes, to reduce the processing workload, the processing path is the feature boundary. The laser ablation amount per pass is generally no more than 0.1 mm. For thick plates, the processing follows the feature boundary in a cyclical manner until the processing is completed. For stepped holes or blind holes, the smaller diameter area is processed first, using the same method as for through holes. The stepped section is processed layer by layer in a ring-shaped area until the stepped surface is completed. The same applies to blind holes.

[0054] 4) Composite processing determination: After the water-guided laser processing is completed, determine whether fine processing or oxide layer removal is required. If so, proceed to step 5); otherwise, proceed to step 6.

[0055] 5) Ultrasonic assisted vibration machining: Select the machining tool according to the process requirements, install the machining tool 223 on the ultrasonic tool holder 222, mark the tool tip position, then install the ultrasonic tool holder 222 on the electric spindle 221, start the ultrasonic vibration function, and execute the task according to the pre-programmed machining program.

[0056] 6) Processing task status judgment: Determine whether the processing task is completed. If "no", adjust the workpiece position and jump to step 3). If "yes", the task ends and the equipment is reset.

[0057] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions made by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A device for ultrasonic / water-conducting laser composite processing of connecting holes in ceramic matrix composites, characterized in that, It includes a basic frame (1), a machining system (2), a transmission system (3), and a workpiece clamping platform (4).

2. The apparatus for ultrasonic / water-guided laser composite processing of connecting holes in ceramic matrix composites according to claim 1, characterized in that, The basic frame (1) includes a device base (11), a Y-axis moving slide (12), an X-axis moving slide (13), and a Z-axis feed slide (14); The processing system (2) includes a water-guided laser processing unit (21) and an ultrasonic-assisted vibration processing unit (22); The transmission system (3) includes an X-axis actuation unit (31), a Y-axis actuation unit (32), and a Z-axis feed unit (33).

3. The apparatus for ultrasonic / water-guided laser composite processing of connecting holes in ceramic matrix composites according to claim 2, characterized in that, The device is fixed to the ground by the equipment base (11), and the Y-axis movable slide (12) provides a mounting carrier for the workpiece and has a Y-axis degree of freedom; The X-axis movable slide (13) provides installation space for the device and has the freedom of movement along the x-axis; The Z-axis feed slide (14) provides a mounting base for the ultrasonic-assisted vibration machining unit (22) and has x-axis feed freedom.

4. The apparatus for ultrasonic / water-guided laser composite processing of connecting holes in ceramic matrix composites according to claim 2, characterized in that, The ultrasonic-assisted vibration machining unit (22) mainly consists of an electric spindle (221), an ultrasonic tool holder (222), and a machining tool (223).

5. The apparatus for ultrasonic / water-guided laser composite processing of connecting holes in ceramic matrix composites according to claim 4, characterized in that, The main electric spindle (221) provides rotational power to drive the machining tool (223) to remove material, while the ultrasonic tool holder (222) provides high-frequency, low-amplitude vibration along the tool axis for the machining tool (223).

6. The apparatus for ultrasonic / water-guided laser composite processing of connecting holes in ceramic matrix composites according to claim 1, characterized in that, The X-axis actuation unit (31), Y-axis actuation unit (32), and Z-axis feed unit (33) are installed perpendicularly to each other to form a three-axis drive system. Under the control of the motion control system, they perform interpolation motion and can complete machining feed equivalent to that of a three-axis machining tool.

7. The apparatus for ultrasonic / water-guided laser composite processing of connecting holes in ceramic matrix composites according to claim 6, characterized in that, The X-axis actuation unit (31) mainly includes a motor, coupling, ball screw, grating ruler, bearing seat, guide rail and slider, etc., for the actuation and positioning of the X-axis moving slide (13). The mechanism movement adopts grating ruler as a closed-loop control means, with a positioning accuracy of 0.01mm. The motor, coupling, ball screw, grating ruler, bearing seat, guide rail, etc. in the X-axis actuation unit (31) are installed on the equipment base (11). The slider is fixed on the X-axis moving slide (13). The X-axis moving slide (13) has only X-axis freedom through the cooperation of the slider and the guide rail, and the X-axis high-precision positioning of the processing system (2) is realized under closed-loop control.

8. The apparatus for ultrasonic / water-conducting laser composite processing of connecting holes in ceramic matrix composites according to claim 6, characterized in that, The Y-axis actuation unit (32) mainly includes a motor, coupling, ball screw, grating ruler, bearing seat, guide rail and slider, etc., for the actuation and positioning of the Y-axis moving slide (12), realizing the position adjustment and processing feed of the workpiece. The mechanism movement adopts the grating ruler as a closed-loop control means, with a positioning accuracy of 0.01mm. The motor, coupling, ball screw, grating ruler, bearing seat, guide rail, etc. in the Y-axis actuation unit (32) are installed on the equipment base (11). The slider is fixed on the Y-axis moving slide (12). The Y-axis moving slide (12) has only the Y-axis degree of freedom through the cooperation of the slider and the guide rail, and the X-axis high-precision positioning of the workpiece to be processed is achieved under closed-loop control.

9. The apparatus for ultrasonic / water-guided laser composite processing of connecting holes in ceramic matrix composites according to claim 6, characterized in that, The Z-axis feed unit (33) mainly includes a motor, coupling, ball screw, grating ruler, bearing seat, guide rail and slider, etc., for the operation and positioning of the Z-axis feed slide (14), realizing the feed of the ultrasonic assisted vibration processing unit (22) along the Z-axis. The mechanism motion adopts the grating ruler as a closed-loop control means, with a positioning accuracy of 0.01mm. The motor, coupling, ball screw, grating ruler, bearing seat, guide rail, etc. in the Z-axis feed unit (33) are installed on the X-axis moving slide (13), and the slider is fixed on the Z-axis feed slide (14). The slider and the guide rail cooperate to make the Z-axis feed slide (14) have only the Z-axis degree of freedom, and realize the cutting feed of the ultrasonic assisted vibration machining unit (22) under closed-loop control.

10. The apparatus for ultrasonic / water-conducting laser composite processing of connecting holes in ceramic matrix composites according to claim 1, characterized in that, The workpiece clamping platform (4) is used to install and clamp the workpiece. Its lower surface is fixedly connected to the upper part of the Y-direction moving slide (12), and the upper surface is used to install the workpiece to be processed. It can adapt to the flexible clamping and fixing of parts of different shapes.

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