Micro-laminated ceramic cutting tool with thermal barrier function and design method thereof

Abstract

The application discloses a micro-laminated ceramic cutter with a thermal barrier function and a design method thereof, and comprises the following steps: due to the alternating residual tensile stress and residual compressive stress generated by the laminated structure, the total number of layers of the cutter is designed as a symmetric structure with 3, 5 or 7 layers, the middle is a base layer, and the rest are thermal barrier layers; a two-dimensional simulation model of orthogonal cutting is established, the thermal physical parameters of a workpiece material are input, the thermal physical parameters of the surface layer of the cutter are assumed to be constant, and the layer thickness and layer thickness ratio of each layer of the micro-laminated ceramic cutter are optimized; based on the ABAQUS simulation software and the structural parameter design of the thermal barrier layer of the micro-laminated ceramic cutter, the thermal physical parameters of the base material of the cutter are optimized; and the interlayer interface bonding form of the micro-laminated ceramic cutter is designed as a mechanical engagement form.

Description

Technical Field

[0001] This invention belongs to the field of machining cutting tool design and manufacturing, specifically relating to a micro-layered ceramic cutting tool with thermal barrier function and its design method. Background Technology

[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.

[0003] Green machining is an inevitable choice for the sustainable development of the manufacturing industry, requiring simultaneous consideration of environmental and economic requirements during the machining process. Traditional wet cutting can effectively reduce cutting temperature and increase tool life. However, wet cutting inevitably increases manufacturing costs and generates waste chips and liquids that are difficult to recycle directly, posing risks to the environment and human health. In recent years, cryogenic machining technology has been increasingly widely used, employing liquid gases such as nitrogen, carbon dioxide, and helium at low temperatures as alternatives to traditional coolants / lubricants, but it still lacks sufficient economic viability. Summary of the Invention

[0004] To address the technical problems existing in the prior art, the present invention provides a micro-layered ceramic cutting tool with thermal barrier function and its design method.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0006] In a first aspect, the present invention provides a design method for a micro-layered ceramic cutting tool with thermal barrier function, comprising the following steps:

[0007] Because the layered structure generates alternating residual tensile and compressive stresses, the total number of tool layers is designed as a symmetrical structure of 3, 5 or 7 layers, with the middle layer being the matrix layer and the rest being thermal barrier layers.

[0008] A two-dimensional simulation model for orthogonal cutting was established. The thermal properties of the workpiece material were input, and the thermal properties of the tool surface were assumed to be constant. The layer thickness and layer thickness ratio of each layer of the micro-stacked ceramic tool were optimized.

[0009] Based on ABAQUS simulation software and the structural parameter design of the thermal barrier layer of the micro-layered ceramic tool, the thermal properties of the tool matrix material were optimized.

[0010] The interlayer interface of the micro-stacked ceramic cutting tool is designed to be a mechanical meshing form.

[0011] From a heat transfer perspective, a heat flow disturbance boundary layer exists during the cutting heat conduction process. This heat flow disturbance layer mainly occurs within a certain thickness range from the rake face of the tool body. The low thermal conductivity of the tool surface layer can effectively reduce the heat flowing into the tool body; however, the heat accumulation effect is significant, easily leading to the appearance of a high-temperature cutting zone on the rake face. The layered structure design can effectively weaken the heat accumulation effect of the tool surface layer. The micron-level layer thickness has a significant impact on the heat conduction mechanism and the heat flow distribution at the tool-chip interface during the cutting process. Therefore, under the premise of selecting a low thermal conductivity material for the surface layer, the focus is on controlling the structural parameters of the surface layer material and the thermal properties of the matrix material. This mainly includes the design of the number of surface thermal barrier layers, layer thickness, and layer thickness ratio, as well as the design of the thermal conductivity of the matrix material.

[0012] From a mechanical perspective, the surface thermal barrier layer of a cutting tool primarily serves to insulate heat and resist wear, while the matrix layer mainly provides toughening. Toughening and reinforcement of brittle ceramic cutting tool materials can be achieved through composite design and micro-layered structure design.

[0013] In some embodiments, the total thickness of the thermal barrier layer is 50 μm to 500 μm. This facilitates manual layering during the hot-pressing sintering process.

[0014] In some embodiments, the highest cutting temperature and heat flux density on the tool rake face are used as metrics in the process of optimizing the layer thickness and layer thickness ratio of each layer of the micro-layered ceramic tool.

[0015] In some embodiments, the highest cutting temperature and heat flux density on the tool rake face are used as metrics in the process of optimizing the thermophysical parameters of the tool matrix material.

[0016] Preferably, the thermal property parameter is the thermal conductivity λs.

[0017] In some embodiments, the internal material of each layer of the micro-stacked ceramic cutting tool is designed as a homogeneous material, while the interlayer interface is designed as a heterogeneous material.

[0018] Secondly, the present invention provides a micro-layered ceramic cutting tool with thermal barrier function, comprising a substrate layer and thermal barrier layers symmetrically attached to both sides of the substrate layer; the interlayer interface is a mechanical meshing structure.

[0019] In some embodiments, the number of thermal barrier layers on one side of the substrate layer is 1-3.

[0020] In some embodiments, the total thickness of the thermal barrier layer is 50 μm to 500 μm.

[0021] In some embodiments, when the number of thermal barrier layers n>1, the layer thickness ratio e=h n-1 / h n , n is the nth layer from the outermost layer of the tool towards the tool substrate, hn h is the thickness of the nth thermal barrier layer. n-1 The thickness of the (n-1)th thermal barrier layer.

[0022] The matrix layer thickness of the micro-stacked tool is defined as h. s h s =h t -2h b , where h t h represents the total layer thickness of the micro-layered ceramic cutting tool. b The total thickness of the thermal barrier surface layer on one side of the micro-layered ceramic cutting tool. The micro-stacked ceramic cutting tool is considered as a tool structure symmetrical along the center line, and its structure is divided on one side of the tool's center line.

[0023] Preferably, e ≤ 1.

[0024] In some embodiments, the thermal conductivity of the tool substrate is 30-100 W / (m·K).

[0025] Preferably, the thermal conductivity of the tool substrate is 50-90 W / (m·K).

[0026] In some embodiments, before each layer of thermal barrier material is laid, a loading and pressing mold with a surface array of micro-protrusions is used for pre-pressing to make the layers mechanically interlocked.

[0027] After the thermal barrier layers are filled, sintering is carried out to obtain ceramic knives.

[0028] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows:

[0029] The "coating-like" structure of the cutting tool can be realized through micro-layer structure design. The integrated sintering of the thermal barrier surface layer and the substrate layer material of the cutting tool is achieved by vacuum hot pressing sintering, which overcomes the problems of easy wear and peeling of the thermal barrier surface layer of the coated cutting tool during the cutting process. At the same time, this preparation method has the advantages of controllable thermal barrier layer thickness, controllable thermal property parameters, and wear resistance of the surface layer.

[0030] Because of the thermal barrier layer, the cutting tool exhibits excellent thermal barrier properties, enabling directional control of cutting heat conduction, reducing the heat flow into the tool side, effectively cooling the tool matrix, preventing excessively high cutting temperatures, and ensuring tool life and precision cutting. The tool also possesses good wear resistance, avoiding additional cutting heat caused by tool wear, weakening the coupling effect between tool wear and tool temperature, and ultimately extending tool life.

[0031] Finite element method (FEM) simulation software was used to optimize the structural parameters of the thermal barrier surface of the cutting tool and the thermophysical parameters of the matrix material. Toughening the matrix material composition and micro-layered structure of the cutting tool can prevent sudden failure of ceramic cutting tools during cutting. By controlling the structural and thermophysical parameters of the micro-layered ceramic cutting tool, the heat conduction process of the tool can be influenced, allowing more cutting heat to be carried away by the chips, thereby extending tool life and reducing machining costs. Attached Figure Description

[0032] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0033] Figure 1 This is a schematic diagram illustrating the thermal barrier effect of micro-layered ceramic cutting tools during the cutting process;

[0034] Figure 2 A schematic diagram showing the thermal barrier surface structure on one side of the tool centerline when the tool has 5 layers.

[0035] Figure 3 The micro-layer interface bonding forms of micro-layered ceramic cutting tools are: (a) linear, (b) wavy, (c) rectangular, and (d) serrated.

[0036] Figure 4 Flowchart of a design method for micro-layered ceramic cutting tools with thermal barrier function;

[0037] Figure 5 Simulated temperature field and heat flux density field of surface structure parameters for a micro-stacked ceramic cutting tool with 5 layers and a layer thickness ratio e = 1: h b (a) Temperature field and (b) Heat flux density field and h at 500 μm b (c) Temperature field and (d) Heat flux density field at 100 μm. Detailed Implementation

[0038] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0039] The present invention will be further described below with reference to the embodiments.

[0040] Example 1:

[0041] A micro-layered ceramic cutting tool with thermal barrier function, wherein the rake face of the tool is a thermal barrier surface layer and the interlayer interface is parallel to the main cutting edge.

[0042] The design method for micro-layered ceramic cutting tools with thermal barrier function includes the design of the thickness of the micro-layered thermal barrier layer based on the surface thermal barrier function, the design of the thermal conductivity of the matrix material based on the internal cutting thermal conduction characteristics, and the design of the interlayer interface bonding form of the micro-layered ceramic cutting tool based on the mechanical performance requirements of the tool.

[0043] (1) Layer design of micro-layered ceramic cutting tools based on residual stress and thermal barrier function: The micro-layered ceramic cutting tool has a symmetrical structure. Considering the alternating residual tensile and compressive stresses generated by the layered structure, the number of layers is designed to be 5, with the middle layer being the matrix layer and the remaining surface layers being thermal barrier layers. The micro-layered ceramic cutting tool is regarded as a tool structure symmetrical along the centerline. The structure is divided on one side of the tool's centerline as follows: Figure 2 As shown.

[0044] (2) Design of surface thickness and layer thickness ratio of micro-laminated ceramic cutting tools based on surface thermal barrier function: The surface thickness of the thermal barrier of micro-laminated ceramic cutting tools can be adjusted. Considering the practical requirements of manual layering during hot pressing sintering, the layer thickness ratio e=1 is selected, and the total thickness h of the thermal barrier surface layer is designed. b For thicknesses of 500μm, 200μm, and 100μm, a two-dimensional simulation model of a typical difficult-to-machine material (nickel-based superalloy 718) was established using ABAQUS simulation software for orthogonal cutting. The tool surface material was set to constant thermal properties, and the total thickness h of the tool thermal barrier surface was optimized. b This study analyzes the cutting heat conduction behavior at the tool-chip interface during the cutting process, using the highest cutting temperature and heat flux density on the tool rake face as metrics to optimize the total thickness h of the thermal barrier layer on the tool rake face. b It is 100μm.

[0045] (3) Design of thermal properties of matrix material for micro-stacked ceramic cutting tool based on surface thermal barrier function: Based on ABAQUS simulation software and the above-mentioned structural parameter design of surface material, the thermal properties (thermal conductivity λs) of matrix material are further designed. The thermal conductivity λs is designed to be 30, 45, 60, 75 and 90 W / (m·K). The thermal conductivity λs of the tool matrix material is optimized to be 90 W / (m·K) with the highest cutting temperature and heat flux density of the tool rake face as the evaluation index.

[0046] (4) Design of interlayer interface of micro-stacked ceramic cutting tool based on mechanical properties: A loading and pressing mold with micro-protrusion array on the surface is used as a pre-pressing mold for manual layering. After each layer of raw material is filled, a hydraulic press is used to perform a pre-pressing, so that the layers are combined in an interlocking manner.

[0047] The micro-protrusions here can be wavy, prismatic, pyramidal, etc., such as Figure 3 As shown.

[0048] Example 2:

[0049] (1) Layer design of micro-layered ceramic cutting tools based on residual stress and thermal barrier function: The micro-layered ceramic cutting tool has a symmetrical structure. Considering the alternating residual tensile and compressive stresses generated by the layered structure, the number of layers is designed to be 5, with the middle layer being the matrix layer and the remaining surface layers being thermal barrier layers. The micro-layered ceramic cutting tool is regarded as a tool structure symmetrical along the centerline. The structure is divided on one side of the tool's centerline as follows: Figure 2 As shown.

[0050] (2) Design of surface thickness and layer thickness ratio of micro-laminated ceramic cutting tools based on surface thermal barrier function: The surface thickness of the thermal barrier of micro-laminated ceramic cutting tools can be adjusted. Considering the practical requirements of manual layering during hot pressing sintering, a layer thickness ratio of e = 0.5 is selected, and the total thickness h of the thermal barrier surface layer is designed. b The thicknesses are 450μm, 300μm, and 150μm. A two-dimensional simulation model of a typical difficult-to-machine material (nickel-based superalloy 718) is established using ABAQUS simulation software for orthogonal cutting. The tool surface material is set to constant thermal properties, and the total thickness h of the tool thermal barrier surface is optimized. b This study analyzes the cutting heat conduction behavior at the tool-chip interface during the cutting process, using the highest cutting temperature and heat flux density on the tool rake face as metrics to optimize the total thickness h of the thermal barrier layer on the tool rake face. b It is 150μm.

[0051] (3) Design of thermal properties of matrix material for micro-stacked ceramic cutting tool based on surface thermal barrier function: Based on ABAQUS simulation software and the above-mentioned structural parameter design of surface material, the thermal properties (thermal conductivity λs) of matrix material are further designed. The thermal conductivity λs is designed to be 30, 45, 60, 75 and 90 W / (m·K). The thermal conductivity λs of the tool matrix material is optimized to be 90 W / (m·K) with the highest cutting temperature and heat flux density of the tool rake face as the evaluation index.

[0052] (4) Design of interlayer interface of micro-stacked ceramic cutting tool based on mechanical properties: A loading and pressing mold with micro-protrusion array on the surface is used as a pre-pressing mold for manual layering. After each layer of raw material is filled, a hydraulic press is used to perform a pre-pressing, so that the layers are combined in an interlocking manner.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A design method for a micro-layered ceramic cutting tool with thermal barrier function, characterized in that: Includes the following steps: Because the layered structure generates alternating residual tensile and compressive stresses, the total number of tool layers is designed as a symmetrical structure of 3, 5 or 7 layers, with the middle layer being the matrix layer and the rest being thermal barrier layers. The micro-layered ceramic cutting tool with thermal barrier function includes: a substrate layer and thermal barrier layers symmetrically attached to both sides of the substrate layer; the interlayer interface is a mechanical meshing structure; when the number of thermal barrier layers n>1, the layer thickness ratio of the thermal barrier layers is e=hn-1 / hn, where n is the nth layer from the outermost layer of the cutting tool to the substrate side, hn is the thickness of the nth thermal barrier layer, and hn-1 is the thickness of the (n-1)th thermal barrier layer; and e≤1. A two-dimensional simulation model for orthogonal cutting was established. The thermal properties of the workpiece material were input. Assuming that the thermal properties of the tool surface were constant, the layer thickness and layer thickness ratio of each layer of the micro-stacked ceramic tool were optimized. In the process of optimizing the layer thickness and layer thickness ratio of each layer of the micro-stacked ceramic tool, the highest cutting temperature and heat flux density of the tool rake face were used as the evaluation indicators. Based on ABAQUS simulation software and the structural parameter design of the thermal barrier layer of the micro-layered ceramic tool, the thermal properties of the tool matrix material are optimized. In the process of optimizing the thermal properties of the tool matrix material, the highest cutting temperature and heat flux density of the tool rake face are used as the evaluation indicators. The interlayer interface of the micro-stacked ceramic cutting tool is designed to be a mechanical meshing form.

2. The design method for a micro-layered ceramic cutting tool with thermal barrier function according to claim 1, characterized in that: The total thickness of the thermal barrier layer is 50μm~500μm.

3. The design method for a micro-layered ceramic cutting tool with thermal barrier function according to claim 1, characterized in that: The internal material of each layer of the micro-stacked ceramic cutting tool is designed as a homogeneous material, while the interlayer interface is designed as a heterogeneous material.

4. The design method for a micro-layered ceramic cutting tool with thermal barrier function according to claim 1, characterized in that: Before filling each layer of thermal barrier material, a loading and pressing mold with a micro-protrusion array on the surface is used for pre-pressing to make the layers mechanically interlock. After the thermal barrier layers are filled, sintering is carried out to obtain ceramic knives.

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