Microtexture design method suitable for enhancing chip breaking of ceramic-based composite material

Abstract

The invention discloses a micro-texture design method suitable for ceramic-based composite material reinforced chip breaking, and belongs to the technical field of ceramic-based composite material machining tools. The method comprises the following steps: analyzing a fiber weaving mode and mechanical properties of a processed ceramic-based composite material; based on the fiber shear bending fracture theory, a basic micro-texture unit used for guiding fibers in the single direction to be fractured is constructed, the basic micro-texture unit is of a groove-shaped structure, and the core control parameter of the basic micro-texture unit is a texture direction angle alpha; a plurality of basic micro-texture units are combined, and a composite texture pattern capable of implementing guiding-clamping-breaking integrated cooperative control on multi-dimensional fibers is formed on the front tool face of the tool. According to the method, through specific micro-texture design, uncontrollable passive fracture of fibers is converted into active shear bending fracture capable of being accurately guided, and therefore the fiber removal efficiency and the integrity of the machined surface are fundamentally improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ceramic matrix composite machining tools, and particularly relates to a micro-texture design method suitable for enhancing chip breaking of ceramic matrix composites. BACKGROUND

[0002] As a kind of high-performance ceramic matrix composite material, C / SiC composite material has been widely used in key fields such as aerospace thermal protection system and high-speed braking system, by virtue of the combination of carbon fiber reinforced phase and silicon carbide matrix and the significant improvement of the fracture toughness of the matrix material through braiding and needling technology. During the assembly process of such components, turning, milling and other finishing processes are often required. However, the high-strength, multi-dimensionally distributed carbon fiber reinforced phase in the material brings significant machining challenges: in the cutting process, the fibers are difficult to be effectively and cleanly cut, and random fiber pull-out, tearing and matrix debonding often occur, resulting in serious damage to the machined surface and difficulty in controlling the quality, which seriously restricts the high-reliability application of the composite material.

[0003] To improve the cutting performance, textured tool technology has been widely studied. Existing technologies mainly focus on improving the lubrication and friction reduction properties of the tool through surface texture. For example, a surface cross-scale composite micro-molding tool (CN208408566U) is designed mainly to optimize the wettability and retention capacity of the lubricating film, and does not actively control the fracture and removal behavior of the fibers in the composite material. In addition, such methods often involve complex nano-scale textures, which are difficult to prepare and costly, and their practicality is limited. There is no related tool and design method that promotes chip breaking from the aspects of braiding characteristics and material fracture characteristics from a mechanical point of view.

[0004] Therefore, there is an urgent need for a new technical solution to solve this problem in the prior art. SUMMARY

[0005] The technical problem to be solved by the present application is to provide a micro-texture design method suitable for enhancing chip breaking of ceramic matrix composites, which solves the technical problems of large machining surface damage and difficult quality control caused by the difficulty in efficiently and cleanly cutting the multi-dimensionally distributed high-strength carbon fibers in the existing ceramic matrix composite machining.

[0006] The technical solution adopted by the present application is to provide a micro-texture design method suitable for enhancing chip breaking of ceramic matrix composites, comprising the following steps:

[0007] analyze the fiber braiding method and mechanical properties of the ceramic matrix composite being machined;

[0008] Based on the fiber shear bending fracture theory, a basic micro-texture unit for guiding the fracture of single direction fiber is constructed, the basic micro-texture unit is a groove type structure, and a core control parameter of the basic micro-texture unit is a texture direction angle alpha; the texture direction angle alpha is an included angle between a texture groove of the basic micro-texture unit and a main cutting edge.

[0009] A plurality of the basic micro-texture units are combined to form a composite texture pattern on a rake face of the tool, and the composite texture pattern can implement integrated and cooperative control of "guiding-holding-fracturing" on multi-dimensional fibers.

[0010] The texture direction angle alpha is preferably 45 degrees.

[0011] The texture direction angle alpha is preferably 45 degrees.

[0012] The composite texture pattern is any one of M type, # type, S type or wave crest type.

[0013] The geometric parameters of the micro-texture include width d1, blade distance h1, groove spacing h2 and depth h3.

[0014] The micro-texture is prepared by using a laser processing technology, and the laser source is a nanosecond laser, a femtosecond laser or a laser water jet.

[0015] A textured tool is designed and prepared according to a micro-texture design method suitable for reinforcing chip breaking of a ceramic matrix composite, and the basic micro-texture unit or the composite texture pattern is arranged on a rake face of the tool.

[0016] A ceramic matrix composite machining method adopts a textured tool designed and prepared according to a micro-texture design method suitable for reinforcing chip breaking of a ceramic matrix composite to perform turning, milling or drilling machining.

[0017] Through the above design scheme, the application can bring the following beneficial effects:

[0018] 1. A progressive texture design method from "unit control" to "system design" is proposed. This invention is not a simple accumulation of geometric structures, but a complete texture design methodology based on a deep understanding of the weaving characteristics of composite materials and the mechanical behavior of fibers: (1) Starting from the unit: The method starts from the basic micro-texture (such as straight grooves at a specific angle) of controlling fibers in a single direction, and verifies the feasibility of actively guiding the fiber to "shear bending and breakage" through the orientation angle, thus solving the fundamental problem of the difficulty in efficiently cutting fibers. (2) Based on the system: On this basis, the method evolves to design composite textures (such as corrugations and M-types), and through its interwoven ridge network, a functionally coordinated "micro-manipulation system" is constructed, realizing the integrated control of fiber "guidance-bending-breakage". (3) Finally applied: The highest level of this method is the optimized texture (such as M-type) designed precisely for the worst cutting conditions such as the positive fiber direction, which effectively suppresses the macroscopic slippage and accumulation of fibers, and finally realizes the efficient and clean removal of multidimensional distributed fibers, obtaining an unprecedented high surface quality.

[0019] 2. This invention represents a fundamental leap from "passive randomness" to "active orientation" in fiber fracture modes. Traditional processing passively addresses random fiber fracture. The texture designed using the aforementioned progressive method actively guides fibers to slide and bend along a predetermined path, achieving directional "shear bending fracture" at the point of highest stress concentration. This precise control over fracture modes eliminates defects such as debonding, pull-out, and burrs caused by incomplete fiber fracture at its source, achieving a fundamental improvement in processing quality and toughness.

[0020] 3. It possesses a high degree of systematicity and universality, providing a clear path and broad application space for technology transformation. (1) Systematized design: This method provides a clear technical roadmap from basic to advanced, which can be "designed on demand" for different processing scenarios, rather than a single fixed solution. It has rich innovative connotations and strong application flexibility. (2) Universality of processes and tools: This textured design scheme is compatible with a variety of modern processes such as laser processing and can be integrated into existing production lines at low cost. At the same time, its design concept can be seamlessly applied to a variety of tool types and materials such as turning tools, milling cutters, and drills, providing an efficient solution that combines innovation, practicality, and universality for various composite material processing scenarios. Attached Figure Description

[0021] Figure 1 This is a schematic diagram illustrating the decomposition of forces when fibers contact the cutting tool in an embodiment of the present invention;

[0022] Figure 2 This is a schematic diagram illustrating the decomposition of forces during fiber contact texture in an embodiment of the present invention;

[0023] Figure 3A schematic diagram of a basic micro-texture unit in an embodiment of the present application;

[0024] Figure 4 A schematic diagram of a local enlargement of a turning tool and M-type texture in an embodiment of the present application;

[0025] Figure 5 A schematic diagram of a # type texture in an embodiment of the present application;

[0026] Figure 6 A schematic diagram of a wave-peak type texture in an embodiment of the present application;

[0027] Figure 7 A schematic diagram of a S type texture in an embodiment of the present application. DETAILED DESCRIPTION

[0028] The present application is further described below in conjunction with the accompanying drawings and specific embodiments:

[0029] The present application is based on the fiber shear bending fracture theory, and a micro-texture with a specific geometric shape and spatial distribution is prepared on the rake face of a tool by using a laser processing device, so as to actively guide and control the fracture process of the fiber. The design of the micro-texture follows the progressive principle from unit to system.

[0030] First, a groove type micro-texture is constructed as a basic functional unit. The core parameter "texture direction angle a" is the key to control the fiber fracture behavior. The texture direction angle a is the included angle between the texture groove of the basic micro-texture unit and the main cutting edge. When the unbroken fiber begins to contact the tool, the force is as shown in Figure 1 When the fiber contacts the rake face of the tool, it is assumed that the fiber is in a balanced state at this time, and the force is as follows:

[0031] F c = F n (1)

[0032] F t = F f = F n × μ (2)

[0033] F c is the support force of the rake face, F f is the friction force of the fiber, μ is the friction coefficient, F n is the resultant force F R of the fiber, F t is the component force of the fiber on the X axis, which is the pressure of the fiber on the rake face, F R is the component force of the fiber on the Y axis, with the progress of the cutting process, when F t > F f , the fiber is prompted to slide upward.

[0034] Fiber slips up to contact the texture, and is guided by the texture to slip in the direction of the texture. The equilibrium force of the fiber is shown in Fig. 1: Figure 2

[0035] F C2 F p F t ×sin(90-α) (3)

[0036] F a F t ×cos(90-α) (4)

[0037] F f2 F p ×μ (5)

[0038] F p is the resilience of the fiber itself, F c2 is the support force of the texture to the fiber, F a is the component force of F t in the direction of the texture, and is the force to pull the fiber to slip in the direction of the texture. When the direction angle α of the texture changes, the force of the fiber also changes. When the direction angle α becomes larger, according to the formula (4) and (5), the pulling force F a of the fiber increases, and the friction force F f2 decreases, and the bending deformation of the fiber decreases. In the process of the fiber slipping, the direction angle α of the texture is used to guide the change of the bending deformation of the fiber. The bending of the fiber produces a bending moment M, as shown in formula (6), E is the elastic modulus of the fiber, is the moment of inertia of the fiber, d is the diameter of the fiber, and p is the radius of curvature. According to the maximum bending stress formula (7), the bending moment is inversely proportional to the radius of curvature, and M is generated by F c2 , and satisfies that the fiber is bent to the curvature specified by the texture.

[0039]

[0040]

[0041] Therefore, the smaller the direction angle α of the texture, the smaller the radius of curvature of the fiber forced to bend, the more serious the bending, and the maximum stress of the fiber appears on the outer surface. When the critical breaking strength is reached, the fiber breaks. When the direction angle α is 0°, the pulling force F a ​Theoretically, this is not possible. When the orientation angle α is smaller, the bending stress is greater, making fiber breakage easier and resulting in shorter chips. As the orientation angle α gradually increases, the bending stress decreases, insufficient to cause independent breakage. At this point, the process relies on the compression and shearing effects of the texture, which is relatively unstable. Therefore, the resulting fiber chips may grow longer, and the fracture surface mainly exhibits shear fracture characteristics. When the orientation angle α is 90°, the supporting force F... c2 Theoretically, it doesn't exist; the traction force F t With F a equal.

[0042] Based on basic microtextile units, a functionally synergistic "fiber manipulation system" is constructed by combining multiple grooved microtextures into composite texture patterns such as M-shape, S-shape, #-shape, or wave-shaped. This system can simultaneously implement integrated control of "guidance-bending-breakage" of fibers in multiple directions, and is especially suitable for harsh working conditions such as positive fiber direction. The microtexture scale distribution range is: width d1 is 7-30μm, depth h3 is 10-20μm, distance from the blade h1 is 50-80μm, and groove spacing h2 is 40-50μm.

[0043] The method of this invention has high flexibility and wide process adaptability in application. Specifically, when processing composite materials with fibers in a single direction, a basic groove texture can be used to achieve efficient chip breaking. However, when facing complex fiber directions with multidimensional distribution, especially in intermittent machining conditions such as milling, composite textures such as M-type and #-type are preferred to achieve stable control of the fibers through their synergistic effect.

[0044] The method of this invention exhibits excellent versatility across different tool types and laser processes: for turning tools, threading tools, straight-edged end mills, and drills, a three-axis linkage laser device can be used to accurately prepare the texture; for end mills and drills with helical edges, a four-axis linkage device is required. There are no specific restrictions on the type of laser source; nanosecond lasers, laser water jets, femtosecond lasers, etc., are all applicable. This ensures that the technology can be seamlessly integrated into existing manufacturing systems at a low cost and high efficiency.

[0045] Example 1: Basic grooved microtexture (for unidirectional fibers). This example is for turning C / SiC composite materials with unidirectional carbon fiber lay-up.

[0046] Textile design: such as Figure 3 As shown, a series of straight-groove microtextures with a certain angle (α) to the main cutting edge are prepared on the rake face of a carbide turning tool / PCD turning tool. The orientation angle α of the microtexture is preferably 45°. The width d1 of a single microtexture is 8 μm, and the depth h3 is 15 μm. The distance h1 from the textured area to the cutting edge is 50 μm, and the groove spacing h2 is 50 μm.

[0047] Fabrication parameters: A nanosecond fiber laser was used for processing, with a laser power of 20W, a pulse frequency of 20kHz, and a scanning speed of 10mm / s. A clear outline and slag-free texture morphology were obtained by repeated single scans.

[0048] Technical results: Compared with the same untextured tool, under the same cutting parameters (vc = 60m / min, f = 0.05mm / r), the fiber pull-out defects of the workpieces processed by this textured tool are significantly reduced, the chips are transformed from disordered long fiber bundles into uniform short chips, and the cutting force is reduced by 58.8%, which proves the effectiveness of guiding the fiber to bend and break in a directional manner.

[0049] Example 2: M-type composite texture (for multi-dimensional fibers, such as two-dimensional woven materials). This example is for the milling of two-dimensional / three-dimensional woven C / SiC composite materials.

[0050] Textile design: such as Figure 4 As shown, an M-type composite texture was fabricated on the rake face of a PCD end mill. This texture consists of two sets of interwoven microgrooves with orientation angles of +45° and +135°, forming a network capable of capturing multi-directional fibers. The width d1 of the microgrooves is 10 μm, the depth h3 is 15 μm, the groove spacing h2 is 45 μm, and the distance from the cutting edge h1 is 80 μm.

[0051] Fabrication parameters: Nanosecond fiber lasers or laser water jet systems are used for processing to balance processing accuracy and heat-affected zone control. Taking nanosecond fiber laser processing as an example, the laser power is 17W and the scanning speed is 10mm / s.

[0052] Technical Results: Under interrupted milling conditions, the M-type texture of this embodiment exhibits superior adaptability compared to the unidirectional texture of Example 1. The machined surface shows virtually no visible fiber pull-out or burrs. Simultaneously, tool life is extended because the fibers are effectively cut rather than repeatedly crushed.

[0053] When faced with complex machining conditions, different texture shapes and texture parameters (distance from the cutting edge, texture spacing, etc.) can be selected to adapt to the machining tools.

[0054] This invention provides a textured tool design method that can actively guide and control the fiber breakage process, fundamentally improving the surface quality of the machined surface through stable and reliable breakage mode transformation.

[0055] The implementation of the present invention is not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and are included within the protection scope of the present invention.

Claims

1. A micro-texture design method for chip breaking enhancement of ceramic matrix composites, characterized by: The method comprises the following steps: analyzing the fiber weaving mode and mechanical properties of the ceramic matrix composite material to be processed; based on the fiber shear bending fracture theory, a basic micro-texture unit for guiding the fracture of single direction fiber is constructed, the basic micro-texture unit is a groove structure, and a core control parameter of the basic micro-texture unit is a texture direction angle α; the texture direction angle α is an included angle between a texture groove of the basic micro-texture unit and a main cutting edge; a plurality of basic micro-texture units are combined to form a composite texture pattern on a rake face of the tool, the composite texture pattern can implement integrated and cooperative control of "guiding-holding-fracturing" on multi-dimensional fibers.

2. The method of claim 1, wherein: The texture direction angle α is in a range of 0° to 180°.

3. The method of claim 1, wherein: The texture direction angle α is preferably 45°.

4. The method of claim 1, wherein: The composite texture pattern is any one of M type, # type, S type or wave crest type.

5. The method of claim 1, wherein: Geometric parameters of the micro-texture include width d1, distance from edge h1, groove spacing h2 and depth h3.

6. The method of claim 1, wherein: The micro-texture is prepared by laser processing technology, and a laser source is a nanosecond laser, a femtosecond laser or a laser water jet.

7. A textured tool designed and produced according to the method of any one of claims 1 to 6, characterized in that: The basic micro-texture unit or the composite texture pattern is arranged on the rake face of the tool.

8. A method of processing a ceramic matrix composite material, characterized by: The textured tool of claim 7 is used for turning, milling or drilling.

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