A method and system for monitoring and controlling high-speed milling of Ti2AlNb alloy

Abstract

This application belongs to the field of machining technology for difficult-to-machine materials, specifically disclosing a method and system for high-speed milling and monitoring of Ti2AlNb alloys. The method first performs scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analysis on the surfaces of the machined tool and Ti2AlNb alloy workpiece to obtain wear information such as tool coating delamination and material adhesion, and characteristic information such as adiabatic shear bands and oxide layers on the workpiece surface. Through correlation analysis, an intrinsic relationship model is established between tool wear mechanisms (such as coating delamination caused by periodic impacts and material adhesion caused by frictional heat) and workpiece surface formation mechanisms (such as adiabatic shearing and high-temperature oxidation). Based on this model, a method is proposed to indirectly and effectively diagnose tool wear status and machining stability by monitoring changes in workpiece surface morphology and composition, providing a new comprehensive criterion and method for process monitoring and optimization of efficient and high-quality machining of Ti2AlNb alloys.

Description

Technical Field

[0001] This application belongs to the field of machining technology for difficult-to-machine materials, and more specifically, relates to a method and system for high-speed milling linkage monitoring of Ti2AlNb alloy. Background Technology

[0002] Ti2AlNb alloys have become important materials for key components in the aerospace field due to their excellent high-temperature strength, high specific strength, and good corrosion resistance. However, due to the high strain rate sensitivity, poor thermal conductivity, and strong chemical reactivity of this alloy at high temperatures, it is prone to problems such as rapid tool wear and workpiece surface quality degradation during high-speed milling, accompanied by significant microstructure evolution and surface chemical reactions in the machining area.

[0003] Currently, most studies on the processing of this material analyze tool wear and workpiece surface morphology separately, lacking a systematic research method that links the two. In reality, tool wear behaviors such as coating peeling and material adhesion are closely intertwined with the formation mechanisms of features like adiabatic shear bands and oxide layers on the workpiece surface, but existing technologies have not fully revealed their intrinsic correlation and coupling effects. Traditional characterization methods struggle to accurately and deeply analyze the microstructure of adiabatic shear bands—closely related to localized intense plastic deformation and thermal effects—as well as the oxidation behavior of freshly formed surfaces instantaneously during processing.

[0004] Therefore, how to effectively monitor the linkage between tool wear and workpiece surface characteristics during high-speed milling of Ti2AlNb alloy is an urgent problem to be solved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this application is to provide a method and system for monitoring the linkage between high-speed milling of Ti2AlNb alloys, which can effectively achieve linkage monitoring between tool wear and workpiece surface characteristics during high-speed milling of Ti2AlNb alloys.

[0006] To achieve the above objectives, in a first aspect, this application provides a method for high-speed milling linkage monitoring of Ti2AlNb alloy, comprising the following steps: S10, during the high-speed milling of Ti2AlNb alloy, samples were taken at different time points to obtain the cutting tool and Ti2AlNb alloy workpiece; S20. The sampled cutting tool was subjected to scanning electron microscopy morphology observation and energy dispersive spectroscopy composition analysis to identify the coating layering characteristics, material adhesion characteristics and chemical wear characteristics of the cutting tool. S30. The morphology of the sampled Ti2AlNb alloy workpiece was observed by scanning electron microscopy and the composition was analyzed by energy dispersive spectroscopy to identify the morphological features of the adiabatic shear band and the surface oxidation features of the workpiece surface. S40, Correlation analysis is performed between the tool features identified in step S20 and the workpiece surface features identified in step S30 to establish a correspondence model between tool wear modes and workpiece surface features; S50, based on the aforementioned correspondence model, the machining status is diagnosed by monitoring workpiece surface features and / or tool wear features, and process adjustments are guided.

[0007] As a further preferred embodiment, in step S10, the different time points include the new tool state, after 15 minutes of continuous milling, and after 30 minutes of continuous milling.

[0008] As a further preferred embodiment, in step S20, the coating delamination characteristic is caused by the tool coating material being subjected to periodic mechanical impact loads.

[0009] As a further preferred embodiment, in step S20, the material adhesion characteristic is caused by friction between the tool and the chips, and energy dispersive spectroscopy analysis confirms that the adhesive material contains Nb elements from the workpiece, thereby determining it as adhesive wear.

[0010] As a further preferred embodiment, step S20, performing energy dispersive spectroscopy (EDS) analysis on the cutting tool includes: performing EDS point scanning analysis on the adhesion region of the cutting tool and comparing it with the cutting tool substrate region.

[0011] As a further preferred embodiment, in step S30, the morphological characteristics of the adiabatic shear band are characterized by alternating light and dark parallel stripes. The reason for this is that the Ti2AlNb alloy softens locally under high-speed shear deformation and undergoes dynamic recrystallization. The surface oxidation characteristics are characterized by a higher oxygen content on the surface than in the substrate. This is because the high processing temperature causes the fresh metal surface to react with air to form an oxide film.

[0012] As a further preferred embodiment, in step S40, the corresponding relationship model establishes at least the following associations: both the tool coating layering and the formation of the workpiece thermal shear band are related to mechanical impact and thermal load; both the degree of tool material adhesion and the degree of workpiece surface oxidation are positively correlated with the temperature of the cutting zone.

[0013] As a further preferred embodiment, in step S50, the diagnosis of machining status and guidance of process adjustment includes: indirectly assessing the wear condition of the tool and the thermal properties of the cutting zone by periodically offline detecting the regularity of the thermal shear band and / or the thickness of the oxide layer on the workpiece surface. The force load level is used to provide tool change warnings or optimize cutting parameters.

[0014] As a further preferred embodiment, in step S50, the diagnosis of machining status and guidance of process adjustment further includes: online monitoring of the spindle power signal during the machining process.

[0015] Secondly, this application provides a high-speed milling linkage monitoring system for Ti2AlNb alloy, used to implement the steps of the method as described in any one of the above, including: The sampling unit is used to take samples at different time points during the high-speed milling of Ti2AlNb alloy to obtain the tool and Ti2AlNb alloy workpiece; The first detection unit is used to perform scanning electron microscopy morphology observation and energy dispersive spectroscopy composition analysis on the sampled cutting tool to identify the coating layering characteristics, material adhesion characteristics and chemical wear characteristics of the cutting tool. The second detection unit is used to perform scanning electron microscopy morphology observation and energy dispersive spectroscopy composition analysis on the machined surface of the sampled Ti2AlNb alloy workpiece to identify the morphological features of the thermal shear band and the surface oxidation features of the workpiece surface. The correlation analysis unit is used to correlate the tool features identified by the first detection unit with the workpiece surface features identified by the second detection unit, and to establish a correspondence model between the tool wear mode and the workpiece surface features. The diagnostic unit is used to diagnose the machining status based on the correspondence model by monitoring the surface features of the workpiece and / or the wear characteristics of the tool, and to guide process adjustments.

[0016] The Ti2AlNb alloy high-speed milling linkage monitoring method provided in this application has the following effects: By co-characterizing the tool and workpiece in the same machining process, the coating delamination, material adhesion, and chemical wear characteristics of the tool, as well as the morphology of the adiabatic shear band and oxidation characteristics of the workpiece surface, are acquired simultaneously. An intrinsic correlation model between the two is established, enabling indirect diagnosis of the machining state by monitoring workpiece surface features and / or tool wear characteristics based on this model. This method deeply couples the tool wear mechanism with the workpiece surface formation mechanism, revealing the combined influence of factors such as periodic impact and frictional heat on the interaction between the tool and workpiece. This allows for effective assessment of the tool wear state and the thermal-mechanical load level in the cutting zone through changes in workpiece surface morphology and composition, achieving effective linkage monitoring of tool wear and workpiece surface features. This provides a comprehensive criterion for process optimization and intelligent monitoring, improving the accuracy and practicality of machining process monitoring. Attached Figure Description

[0017] Figure 1 This is a flowchart of a high-speed milling monitoring method for Ti2AlNb alloy based on the linkage between tool wear and workpiece surface features, provided in an embodiment of this application. Figure 2 These are scanning electron microscope (SEM) images of the bottom edge of a new cutting tool, a cutting tool after 15 minutes of milling, and a cutting tool after 30 minutes of milling, provided in the embodiments of this application; wherein, (a) is a new cutting tool, (b) is a cutting tool after 15 minutes of milling, and (c) is a cutting tool after 30 minutes of milling; Figure 3(a) is a schematic diagram of the point spectrum location and a comparison of the results of energy dispersive spectroscopy analysis of the tool adhesion area (point B) and the substrate area (point A) after milling for 15 minutes, provided in an embodiment of this application. Figure 3(b) is a schematic diagram of the point spectrum location and a comparison of the results of energy dispersive spectroscopy analysis of the tool adhesion area (point D) and the substrate area (point C) after milling for 30 minutes, provided in the embodiment of this application. Figure 4 These are scanning electron microscope images of the processed surface of Ti2AlNb alloy provided in the embodiments of this application, showing the morphology of alternating light and dark thermal shear bands; Figure 5 This is an elemental information diagram obtained from energy dispersive spectroscopy analysis of the processed surface of the Ti2AlNb alloy provided in the embodiments of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0019] It should be understood that, in the description of this application, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0020] This application provides a high-speed milling monitoring method for Ti2AlNb alloy based on the linkage between tool wear and workpiece surface features. This method establishes a correspondence between specific tool wear characteristics and specific workpiece surface morphology by collaboratively characterizing and analyzing the machined tool and workpiece, thereby gaining a deeper understanding of the machining mechanism. This is of great significance for optimizing machining processes, understanding deformation mechanisms, and improving the service performance of components.

[0021] The method for monitoring high-speed milling of Ti2AlNb alloy based on the linkage between tool wear and workpiece surface features provided in this application includes the following steps: S1: At the set milling time points (e.g., new tool, after 15 minutes of milling, after 30 minutes of milling), stop the high-speed milling process of Ti2AlNb alloy and remove the tool or Ti2AlNb alloy workpiece. Clean and dry the tool or Ti2AlNb alloy workpiece, and then clamp it onto the sample stage.

[0022] S2: Use scanning electron microscopy to observe the surface morphology information of the key area of ​​the bottom edge of the tool after milling for 15 minutes and 30 minutes.

[0023] S3: Perform energy dispersive spectroscopy analysis on the cutting tool after 15 minutes of milling and after 30 minutes of milling to obtain elemental information of the key area of ​​the bottom edge of the cutting tool.

[0024] S4: The surface of the processed Ti2AlNb alloy workpiece is observed by scanning electron microscopy to obtain information on its surface morphology.

[0025] S5: Perform energy dispersive spectroscopy analysis on the surface of the processed Ti2AlNb alloy workpiece to obtain its surface element information.

[0026] Further, the scanning electron microscopy observation in step S2 focuses on the coating state of the tool's bottom edge and the material adhesion on the tool surface. Specifically, the scanning electron microscope is used to observe whether coating delamination and micro-cutting phenomena appear on the tool's bottom edge after 15 minutes and 30 minutes of high-speed milling of Ti2AlNb alloy.

[0027] Furthermore, the energy dispersive spectroscopy (EDS) analysis in step S3 is used to detect chemical wear of the cutting tool. EDS point scanning analysis is performed on the adhesion areas of the cutting tool after 15 minutes of milling and after 30 minutes of milling, and the results are compared with those of the tool substrate area. The results of the two analyses are then correlated.

[0028] Further, the scanning electron microscopy observation in step S4 is used to analyze the plastic deformation characteristics of the Ti2AlNb alloy workpiece surface. The focus is on observing the unique microscopic morphological features of the Ti2AlNb alloy workpiece surface.

[0029] Furthermore, the energy dispersive spectroscopy (EDS) analysis in step S5 is used to detect changes in the chemical state of the Ti2AlNb alloy workpiece surface. EDS point scanning analysis is performed on the machined surface of the Ti2AlNb alloy workpiece, and the obtained elemental information is used for mechanistic studies.

[0030] The Ti2AlNb alloy high-speed milling linkage monitoring method provided in this application has the following effects: By co-characterizing the tool and workpiece in the same machining process, the coating delamination, material adhesion, and chemical wear characteristics of the tool, as well as the morphology of the adiabatic shear band and oxidation characteristics of the workpiece surface, are acquired simultaneously. An intrinsic correlation model between the two is established, enabling indirect diagnosis of the machining state by monitoring workpiece surface features and / or tool wear characteristics based on this model. This method deeply couples the tool wear mechanism with the workpiece surface formation mechanism, revealing the combined influence of factors such as periodic impact and frictional heat on the interaction between the tool and workpiece. This allows for effective assessment of the tool wear state and the thermal-mechanical load level in the cutting zone through changes in workpiece surface morphology and composition, achieving effective linkage monitoring of tool wear and workpiece surface features. This provides a comprehensive criterion for process optimization and intelligent monitoring, improving the accuracy and practicality of machining process monitoring.

[0031] In one embodiment, the technical solution to achieve the above objective can be as follows: A high-speed milling monitoring method for Ti2AlNb alloy based on the linkage between tool wear and workpiece surface features, as proposed in this embodiment, has the following process: Figure 1 As shown, an example is: Ti2AlNb alloy was milled at high speed using a carbide-coated end mill. Samples were taken at three different conditions: 1) with a new end mill; 2) after 15 minutes of continuous milling; and 3) after 30 minutes of continuous milling.

[0032] Before placing the sample into the scanning electron microscope (SEM), it must be cleaned with anhydrous ethanol under ultrasonic conditions to remove impurities adhering to the surface. After drying, keep the sample clean and dry for analysis. Mount the clean and dry cutting tool onto the sample stage; if necessary, use conductive adhesive to help fix the tool in place to prevent drift during scanning. Analyze the sample using a field emission scanning electron microscope (Zeiss GeminiSEM 360) and an energy dispersive spectroscopy (AztecLivelite Xplore 30).

[0033] Scanning electron microscopy was performed on the 15-minute and 30-minute cutting tools (e.g.) Figure 2 (As shown). Coating delamination was observed on the bottom edge of both tools, with the 30-minute tool showing more severe delamination. Obvious adhesive residue was present on the tool surface, with a larger adhesive area on the 30-minute tool.

[0034] Energy dispersive spectroscopy (EDS) analysis (as shown in Figures 3(a) and 3(b)) showed that significant Nb peaks were detected in the EDS of the adhesion points (points B and D), while no such feature was found at the tool substrate points (points A and C), confirming that the adhered material was the workpiece material (Ti2AlNb alloy) and that adhesive wear had occurred.

[0035] Microscopic morphology observation of the surface of the milled Ti2AlNb alloy workpiece (e.g.) Figure 4 As shown in the figure, clear alternating light and dark parallel stripes are visible, which are adiabatic shear bands. Energy dispersive spectroscopy (EDS) was performed on the surface of the Ti2AlNb alloy workpiece (e.g., [image of surface scan]). Figure 5 As shown in the figure, oxygen was found to be significantly enriched on the surface, indicating the formation of an oxide layer.

[0036] Association analysis revealed: 1. Delamination of the cutting edge coating and the formation of insulating shear bands on the workpiece surface share common causes: periodic mechanical impact and high thermal load. When coating delamination is severe, the cutting condition of the tool deteriorates, which may exacerbate uneven shear deformation on the workpiece surface.

[0037] 2. Both material adhesion to the cutting edge and oxidation of the workpiece surface originate from the high temperatures during machining. Severe adhesion to the cutting edge often indicates higher temperatures in the cutting zone, which simultaneously exacerbates the oxidation of the workpiece surface.

[0038] 3. The degree of distinctness of the thermal shear band on the workpiece surface and the thickness of the oxide layer can serve as characteristic signals that indirectly reflect the current thermo-mechanical load state and wear degree of the cutting tool.

[0039] Based on the above correlation model, a monitoring strategy is formulated: online monitoring of the spindle power signal during machining, and offline sampling inspection of the workpiece surface morphology (insulation shear band morphology) and oxide color. When the degree of disorder of the insulation shear band on the workpiece surface is found to be aggravated or the oxide color is found to be abnormally deepened, an early warning can be given that the tool may have entered the accelerated wear stage (such as significant coating delamination or large-area adhesion), indicating that the tool needs to be checked or replaced, or the cooling conditions and cutting parameters should be optimized.

[0040] This embodiment combines tool wear analysis with workpiece surface analysis to reveal the coupling mechanism of tool-workpiece interaction in high-speed milling of Ti2AlNb alloy, providing new theoretical basis and practical methods for process optimization and intelligent monitoring.

[0041] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for monitoring and controlling high-speed milling of Ti2AlNb alloy, characterized in that, Includes the following steps: S10, during the high-speed milling of Ti2AlNb alloy, samples were taken at different time points to obtain the cutting tool and Ti2AlNb alloy workpiece; S20. The sampled cutting tool was subjected to scanning electron microscopy morphology observation and energy dispersive spectroscopy composition analysis to identify the coating layering characteristics, material adhesion characteristics and chemical wear characteristics of the cutting tool. S30. The morphology of the sampled Ti2AlNb alloy workpiece was observed by scanning electron microscopy and the composition was analyzed by energy dispersive spectroscopy to identify the morphological features of the adiabatic shear band and the surface oxidation features of the workpiece surface. S40, Correlation analysis is performed between the tool features identified in step S20 and the workpiece surface features identified in step S30 to establish a correspondence model between tool wear modes and workpiece surface features; S50, based on the aforementioned correspondence model, the machining status is diagnosed by monitoring workpiece surface features and / or tool wear features, and process adjustments are guided.

2. The method for high-speed milling linkage monitoring of Ti2AlNb alloy as described in claim 1, characterized in that, In step S10, the different time points include the new tool state, after 15 minutes of continuous milling, and after 30 minutes of continuous milling.

3. The method for high-speed milling linkage monitoring of Ti2AlNb alloy as described in claim 1, characterized in that, In step S20, the coating delamination characteristic is caused by the tool coating material being subjected to periodic mechanical impact loads.

4. The method for high-speed milling linkage monitoring of Ti2AlNb alloy as described in claim 1, characterized in that, In step S20, the material adhesion characteristic is caused by friction between the tool and the chips, and the adhesion material is confirmed to contain Nb elements from the workpiece by energy dispersive spectroscopy analysis, thus it is determined to be adhesive wear.

5. The method for high-speed milling linkage monitoring of Ti2AlNb alloy as described in claim 1, characterized in that, In step S20, the energy dispersive spectroscopy (EDS) analysis of the cutting tool includes: performing an EDS point scan analysis on the adhesion area of ​​the cutting tool and comparing it with the tool substrate area.

6. The method for high-speed milling linkage monitoring of Ti2AlNb alloy as described in claim 1, characterized in that, In step S30, the thermal shear band morphology features are characterized by alternating light and dark parallel stripes. The reason for this is that the Ti2AlNb alloy softens and undergoes dynamic recrystallization under high-speed shear deformation due to local temperature rise. The surface oxidation features are characterized by a higher oxygen content on the surface than in the substrate. This is because the high processing temperature causes the fresh metal surface to react with air to form an oxide film.

7. The method for high-speed milling linkage monitoring of Ti2AlNb alloy as described in claim 1, characterized in that, In step S40, the corresponding relationship model establishes at least the following associations: tool coating delamination and workpiece thermal shear band formation are both related to mechanical impact and thermal load; the degree of tool material adhesion and workpiece surface oxidation are both positively correlated with the cutting zone temperature.

8. The method for high-speed milling linkage monitoring of Ti2AlNb alloy as described in claim 1, characterized in that, In step S50, the diagnosis of machining status and guidance of process adjustment includes: indirectly assessing the wear condition of the tool and the thermal properties of the cutting zone by periodically offline detecting the regularity of the thermal shear band and / or the thickness of the oxide layer on the workpiece surface. The force load level is used to provide tool change warnings or optimize cutting parameters.

9. The method for high-speed milling linkage monitoring of Ti2AlNb alloy as described in claim 1, characterized in that, In step S50, the diagnosis of machining status and guidance of process adjustment also includes: online monitoring of the spindle power signal during machining.

10. A high-speed milling linkage monitoring system for Ti2AlNb alloy, characterized in that, The steps for implementing the method as described in any one of claims 1 to 9 include: The sampling unit is used to take samples at different time points during the high-speed milling of Ti2AlNb alloy to obtain the tool and Ti2AlNb alloy workpiece; The first detection unit is used to perform scanning electron microscopy morphology observation and energy dispersive spectroscopy composition analysis on the sampled cutting tool to identify the coating layering characteristics, material adhesion characteristics and chemical wear characteristics of the cutting tool. The second detection unit is used to perform scanning electron microscopy morphology observation and energy dispersive spectroscopy composition analysis on the machined surface of the sampled Ti2AlNb alloy workpiece to identify the morphological features of the thermal shear band and the surface oxidation features of the workpiece surface. The correlation analysis unit is used to correlate the tool features identified by the first detection unit with the workpiece surface features identified by the second detection unit, and to establish a correspondence model between the tool wear mode and the workpiece surface features. The diagnostic unit is used to diagnose the machining status based on the correspondence model by monitoring the surface features of the workpiece and / or the wear characteristics of the tool, and to guide process adjustments.

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