Intelligent cutter bar based on groove structure and used for monitoring cutting force

Abstract

The invention belongs to the technical field of metal processing intelligent cutters, and provides an intelligent cutter bar for cutting force monitoring based on a groove structure, the intelligent cutter bar comprises a cutter bar, a plurality of side walls of the cutter bar are respectively provided with a groove group, and the groove groups are arranged close to a cutter head; the groove sets are used for locally amplifying the strain of the cutter bar when the cutter bar is stressed, each groove set comprises a plurality of triangular grooves formed in the side wall of the cutter bar, and a *-shaped groove structure is formed among the triangular grooves; the plurality of thin film strain gauges are respectively arranged corresponding to the plurality of groove groups, and the plurality of thin film strain gauges are used for monitoring the strain conditions of the cutter bar when the cutter bar is stressed in different directions. The state intelligent bottleneck of the metal machining cutter is broken through, and the requirement for continuous detection of the cutting force in the manufacturing field is met with low cost and high reliability.

Description

Technical Field

[0001] The present invention belongs to the technical field of intelligent metal processing tools, and in particular relates to an intelligent tool bar based on a groove structure for cutting force monitoring. Background Art

[0002] Metal cutting is a comprehensive technology involving mechanical engineering, materials science and other disciplines. It has the advantages of wide range, controllable machining accuracy and high reliability. It has been widely used in mechanical manufacturing, aerospace and other fields. In recent years, with the development of precision manufacturing technology and intelligent manufacturing technology, real-time monitoring of cutting force is particularly important. By real-time monitoring of cutting force, it is possible to control cutting load, optimize cutting process, evaluate tool status, perform fault diagnosis and life prediction on the machining process, thereby improving the reliability of machining quality.

[0003] At present, the mechanical processing industry mainly uses discrete devices to measure cutting forces. Such devices are large in size and will impose certain restrictions on the size of the workpiece that can be processed after installation, so their application is relatively limited in the actual processing process. In order to solve the above problems, the Chinese patent with publication number CN104139322A discloses an intelligent tool holder for four-dimensional cutting force monitoring, in which the force measuring component is connected to the tool holder by bonding. This connection method is prone to failure under high temperature and lubricating oil corrosion conditions, and its sensing monitoring position is far away from the processing position, so the collected data will have a certain delay. For example, the Chinese patent with publication number CN115673800A proposes an intelligent tool holder for real-time monitoring of multi-dimensional cutting force. The intelligent tool holder achieves the effect of strain amplification through a bow-shaped structure, but the structure has high requirements on the dimensional tolerance and assembly of each component, and has a greater impact on the rigidity of the overall structure of the tool, which has a certain adverse effect on the processing accuracy. In summary, at present, there is no cutting force collection solution with a small volume, simple preparation, low cost and high reliability at home and abroad. Summary of the invention

[0004] The purpose of the present invention is to provide an intelligent tool bar based on a groove structure for cutting force monitoring to solve the above-mentioned problems, break through the bottleneck of tool status intelligence, and meet the needs of continuous detection of cutting force in the manufacturing field with lower cost and higher reliability.

[0005] To achieve the above object, the present invention provides the following solution: an intelligent tool bar for cutting force monitoring based on a groove structure, comprising:

[0006] A tool bar, wherein groove groups are respectively arranged on several side walls of the tool bar, several of the groove groups are arranged near the tool head, and several of the groove groups are used to locally amplify the strain of the tool bar when subjected to force, and the groove group includes several triangular grooves opened on the side walls of the tool bar, and a crisscross groove structure is formed between the several triangular grooves;

[0007] A plurality of thin film strain gauges are respectively arranged corresponding to the plurality of groove groups, and the plurality of thin film strain gauges are used to monitor the strain of the tool bar when it is subjected to forces in different directions.

[0008] Preferably, the groove group includes eight groups of triangular grooves, the contours of the eight groups of triangular grooves are all right triangles, and the eight groups of triangular grooves are centrally symmetrically distributed to form a cross-shaped structure.

[0009] Preferably, two adjacent triangular grooves are separated by a separation beam.

[0010] Preferably, the length of the right-angle side of the triangular groove is 0% to 50% of the width of the knife bar, and the width of the partition beam is 0% to 20% of the width of the knife bar;

[0011] The depth of the triangular groove is 0% to 50% of the width of the knife bar.

[0012] Preferably, a plurality of the thin film strain gauges are respectively arranged on the outer wall of the tool rod close to the groove group or on the partition beam.

[0013] Preferably, the thickness of the thin film strain gauge is 400-1000 nm.

[0014] Preferably, the surface of the tool rod is covered with an aluminum oxide film, and the thin film strain gauge is arranged on the aluminum oxide film.

[0015] Preferably, the surface of the thin film strain gauge is covered with a protective layer.

[0016] Preferably, the surface of the protective layer is covered with a moisture-proof layer.

[0017] Compared with the prior art, the present invention has the following advantages and technical effects: the main function of the groove group is to amplify the strain locally at the groove group when the tool bar is subjected to force, to assist the thin film strain gauge in realizing the measurement of tiny cutting force, and to help improve the measurement accuracy; the main function of the thin film strain gauge is to monitor the strain at the groove group. On the whole, the present invention processes a number of crisscross groove structures at the position of the tool bar close to the tool head, amplifies the local strain while ensuring the rigidity, realizes the measurement of tiny cutting force, and improves the measurement accuracy. At the same time, a thin film strain gauge is set in the crisscross groove structure, and by applying the thin film strain gauge to the cutting force monitoring of cutting processing, it has the advantages of strong operability, simple process, and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is a front view of the intelligent knife bar of the present invention;

[0020] Figure 2 A top view of the intelligent tool bar of the present invention;

[0021] Figure 3 A bottom view of the intelligent tool bar of the present invention;

[0022] Figure 4 is a schematic diagram of a groove group of the present invention;

[0023] Figure 5 This is a processing flow chart of the intelligent tool bar of the present invention;

[0024] Figure 6 A schematic diagram of the arrangement of a thin film strain gauge of the present invention;

[0025] Figure 7 It is a schematic diagram of the structure of the thin film strain gauge of the present invention;

[0026] Among them, 1. tool rod; 2. groove group; 21. triangular groove; 22. partition beam; 3. film strain gauge. DETAILED DESCRIPTION

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Embodiment 1:

[0030] Reference Figure 1-Figure 4 The present invention provides an intelligent tool bar for cutting force monitoring based on a groove structure, comprising:

[0031] A tool bar 1, wherein groove groups 2 are respectively arranged on several side walls of the tool bar 1, wherein the groove groups 2 are arranged near the tool head, and the groove groups are used to locally amplify the strain of the tool bar 1 when subjected to force, and the groove groups 2 include several triangular grooves 21 arranged on the side walls of the tool bar 1, and a M-shaped groove structure is formed between the several triangular grooves 21;

[0032] A plurality of thin film strain gauges 3 are respectively arranged corresponding to the plurality of groove groups 2 , and the plurality of thin film strain gauges 3 are used to monitor the strain of the tool bar 1 when it is subjected to forces in different directions.

[0033] The main function of the groove group 2 is to amplify the strain locally at the groove group 2 when the tool bar is subjected to force, assist the thin film strain gauge 3 to measure the tiny cutting force, and help improve the measurement accuracy; the main function of the thin film strain gauge 3 is to monitor the strain at the groove group 2. On the whole, the present invention processes a plurality of crisscross groove structures at the position of the tool bar close to the tool head, amplifies the local strain while ensuring the rigidity, realizes the measurement of the tiny cutting force, and improves the measurement accuracy. At the same time, a thin film strain gauge is set in the crisscross groove structure, and the thin film strain gauge is applied to the cutting force monitoring of the cutting process, which has the advantages of strong operability, simple process, and low cost.

[0034] According to a further optimized solution, the groove group 2 includes eight groups of triangular grooves 21 , the contours of the eight groups of triangular grooves 21 are all right triangles, and the eight groups of triangular grooves 21 are centrally symmetrically distributed to form a cross-shaped structure.

[0035] In a further optimized solution, two adjacent triangular grooves 21 are separated by a separation beam 22 .

[0036] like Figure 4As shown, a group of right-angled sides of any triangular groove 21 is separated from the right-angled sides of an adjacent triangular groove 21 by a dividing beam 22, and at the same time, the hypotenuse of the triangular groove 21 is separated from the hypotenuse of another adjacent triangular groove 21 by a dividing beam 22, thereby forming eight groups of dividing beams 22, and the eight groups of dividing beams 22 intersect each other to form a cross-shaped structure. While ensuring that the tool bar 1 meets the rigidity for use, the groove group 2 can amplify the strain of the tool bar 1 when it is stressed, which is convenient for the numerical monitoring of the thin film strain gauge 3.

[0037] To further optimize the solution,

[0038] The length of the right angle side of the triangular groove 21 (i.e., a shown in the figure) is 0% to 50% of the width of the shank 1, and the width of the partition beam 22 (i.e., b shown in the figure) is 0% to 20% of the width of the shank 1;

[0039] The depth of the triangular groove 21 is 0% to 50% of the width of the shank 1 .

[0040] According to a further optimized solution, a plurality of thin film strain gauges 3 are respectively arranged on the outer wall of the tool rod 1 close to the groove group 2 or on the partition beam 22 .

[0041] According to a further optimization scheme, the thickness of the thin film strain gauge 3 is 400-1000 nm.

[0042] According to a further optimized solution, the surface of the shank 1 is covered with an aluminum oxide film, and the thin film strain gauge 3 is arranged on the aluminum oxide film.

[0043] In a further optimized solution, the surface of the thin film strain gauge 3 is covered with a protective layer.

[0044] To further optimize the solution, aluminum oxide film can be used as the protective layer.

[0045] To further optimize the solution, the surface of the protective layer is covered with a moisture-proof layer.

[0046] Embodiment 2:

[0047] The above-mentioned method for preparing an intelligent tool bar based on a groove structure for cutting force monitoring comprises:

[0048] Tool bar structure design: Model the tool bar 1, set the groove group 2 with appropriate parameters at the appropriate position of the tool bar 1, and perform simulation analysis on the tool bar 1 to mark the points with small interference and large strain;

[0049] Mask preparation: According to the design of thin film resistors, corresponding masks are prepared by laser cutting or metal etching for subsequent deposition;

[0050] Groove group processing: processing a groove group 2 on the tool bar 1;

[0051] Preparation of thin film strain gauge: grinding and polishing the tool rod 1, and then preparing an aluminum oxide film on the surface of the tool rod 1 by electron beam evaporation, and then preparing a thin film strain gauge 3 on the basis of the aluminum oxide film by magnetron sputtering;

[0052] Testing and characterization of thin film strain gauges; measuring geometric parameters and resistance values ​​of the prepared thin film strain gauge 3, and then characterizing the thin film strain gauge;

[0053] Cutter bar calibration: Connect the thin film strain gauge 3 to the Wheatstone circuit bridge, and apply three-axis forces of different magnitudes to the tool bar 1 in turn to calibrate the thin film strain gauge 3;

[0054] Tool bar packaging; preparing a protective layer on the thin film strain gauge 3 and coating a layer of moisture-proof glue on its surface.

[0055] Specifically, Figure 5 As shown, the whole preparation process of this embodiment includes:

[0056] (1) Tool bar structure design: Model the tool bar 1 of the turning tool, set the groove group 2 at the appropriate position of the tool bar 1, and set the right-angle length of the triangular groove 21, the width of the partition beam 22, and the groove depth. In the finite element software, simulate and analyze the force on the tool bar 1 of this structure, fix the rear end face of the tool bar 1, load the tool tip in three different directions of X, Y, and Z, and compare the deformation of the tool tip with the state of the tool bar 1 without the window frame structure. If the deformation difference is small, mark the points with small cross interference and large strain at the groove group 2, and observe the distribution of the points to design the corresponding thin film strain gauge 3; if the deformation difference is large, the structural parameters and position of the groove group 2 can be adjusted, and the above work can be repeated.

[0057] Specifically, by introducing a groove structure on the surface of the tool bar 1 to achieve the function of three-way force decoupling and strain amplification, a lathe is selected during simulation, and the width and height of the tool bar 1 are 20mm×20mm. The rear surface of the tool handle is fixed, and different forces of 0 to 200N are applied at the tip of the tool to simulate the change of cutting force, and the stress distribution on the surface of the tool bar and the displacement change of the tool tip are observed. Among them, the stress distribution is used to provide a basis for the arrangement of the thin film strain gauge 3, and the displacement of the tool tip is used to observe the stiffness change of the tool bar 1 to avoid the adverse effect of excessive stiffness change on the processing error. In this simulation embodiment, the length of the right angle side of the triangular groove 21 is 7.5mm, the depth is 2mm, and the axial distance between the edge closest to the tool tip and the tool tip is 25.43mm. After simulation analysis, compared with before grooving, the stress near the groove after grooving increased by 20%-200%, and the displacement at the tool tip only increased by 4.3%. The structure can achieve decoupling of three-dimensional forces with an error of no more than 20%, and the effects of the three-dimensional forces satisfy the linear superposition characteristics. The cutting forces in the three directions can be subsequently solved through the joint measurement results, which can meet the relevant measurement requirements.

[0058] (2) Mask preparation: According to the design of the thin film resistor, the corresponding mask is prepared by laser cutting or metal etching for subsequent deposition.

[0059] (3) Groove structure processing: The corresponding groove group 2 is processed on the tool bar 1 by milling or other methods.

[0060] (4) Preparation of thin film strain gauge: The surface of the tool rod 1 is ground and polished until the surface is smooth and free of scratches, and then the tool rod 1 is ultrasonically cleaned with acetone, anhydrous ethanol and ultrapure water in turn. The aluminum oxide film is prepared by electron beam evaporation. During the preparation process, the film growth rate is controlled at 0.4-0.6A, and the film thickness is controlled at 1-3um. Then, the surface is cleaned again with acetone, anhydrous ethanol and ultrapure water. A thin film strain gauge with a thickness of 400-1000nm is prepared by magnetron sputtering using chromium-nickel alloy as the material.

[0061] In this embodiment, a 2 um aluminum oxide film is prepared at a film growth rate of 0.5 A / s under a vacuum degree of 3×10-3 Pa. Then, a thin film strain gauge with a thickness of 600-800 nm is prepared by magnetron sputtering using nickel alloy as the material under the conditions of a vacuum degree of 0.6 Pa and a power of 80 W.

[0062] Specifically, six groups of grooves 2 are provided on the surface of the tool bar 1, and six thin film strain gauges 3 are arranged near three of the grooves 2, with two thin film strain gauges 3 arranged on the surface of each groove group 2 (see Figure 1-Figure 3 The thin film strain gauge 3 is composed of two square resistors with a side length of 1 mm and three sections of resistors. Its specific dimensions are as follows: Figure 7 As shown in the figure, h=1.00, i=0.12, j=2.10, k=0.20 (unit: mm).

[0063] During the design, according to the simulation results, the points with large strain near the groove group and good three-way force decoupling effect (for example, only when the cutting force in the X direction acts, there is a large stress, and when the forces in the other two directions act, the stress is small) are selected to arrange the strain gauges. The strain gauges can be arranged in the partition beam 22 or other parts around the groove group 2. This embodiment shows a method of arranging the thin film strain gauge 3 as follows Figure 6 As shown in the figure, a=31.73, b=37.73, c=24.73, d=30.73, e=25.20, f=31.73, g=1.18 (unit: mm).

[0064] (5) Testing and characterization of thin film strain gauge: The geometric parameters and resistance value of the prepared thin film strain gauge 3 are measured and compared with the theoretical value. Under the condition that the difference between the two is not large, the thin film strain gauge is further characterized by using instruments such as SEM.

[0065] (6) Calibration and packaging of the smart tool bar: After the characterization is completed, the thin film strain gauge 3 is connected to the Wheatstone bridge circuit with the help of a bonding machine, and three-axis forces of different magnitudes are applied to the tool tip in turn to calibrate the thin film strain gauge. At the same time, a layer of aluminum oxide with a thickness of 2 μm is prepared on the thin film strain gauge as a protective layer, and a layer of moisture-proof glue is applied on its surface to prevent the coolant from affecting the performance of the strain gauge.

[0066] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0067] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. An intelligent tool bar based on a groove structure for cutting force monitoring, characterized in that ,include: A knife bar (1), wherein groove groups (2) are respectively arranged on a plurality of side walls of the knife bar (1), wherein a plurality of the groove groups (2) are arranged close to the knife head, and the plurality of the groove groups are used to locally amplify the strain of the knife bar (1) when subjected to force, and the groove group (2) comprises a plurality of triangular grooves (21) arranged on the side walls of the knife bar (1), and a crisscross groove structure is formed between the plurality of triangular grooves (21); A plurality of thin film strain gauges (3) are respectively arranged corresponding to the plurality of groove groups (2), and the plurality of thin film strain gauges (3) are used to monitor the strain conditions of the knife bar (1) when subjected to forces in different directions.

2. The intelligent tool bar for cutting force monitoring based on a groove structure according to claim 1, characterized in that: The groove group (2) comprises eight groups of triangular grooves (21), the contours of the eight groups of triangular grooves (21) are all right triangles, and the eight groups of triangular grooves (21) are centrally symmetrically distributed to form a cross-shaped structure.

3. The intelligent tool bar for cutting force monitoring based on a groove structure according to claim 2, characterized in that: Two adjacent triangular grooves (21) are separated by a separation beam (22).

4. The intelligent tool bar for cutting force monitoring based on a groove structure according to claim 3 is characterized in that: The length of the right-angled side of the triangular groove (21) is 0% to 50% of the width of the knife bar (1), and the width of the partition beam (22) is 0% to 20% of the width of the knife bar (1); The depth of the triangular groove (21) is 0% to 50% of the width of the knife bar (1).

5. The intelligent tool bar for cutting force monitoring based on a groove structure according to claim 3, characterized in that: The plurality of thin film strain gauges (3) are respectively arranged on the outer wall of the knife rod (1) close to the groove group (2) or on the partition beam (22).

6. The intelligent tool bar for cutting force monitoring based on a groove structure according to claim 3, characterized in that: The thickness of the thin film strain gauge (3) is 400-1000 nm.

7. The intelligent tool bar for cutting force monitoring based on a groove structure according to claim 3, characterized in that: The surface of the knife rod (1) is covered with an aluminum oxide film, and the thin film strain gauge (3) is arranged on the aluminum oxide film.

8. The intelligent tool bar for cutting force monitoring based on a groove structure according to claim 3, characterized in that: The surface of the thin film strain gauge (3) is covered with a protective layer.

9. The intelligent tool bar for cutting force monitoring based on a groove structure according to claim 8, characterized in that: The surface of the protective layer is covered with a moisture-proof layer.

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