A machining device and machining method

Abstract

The application discloses a kind of machining devices, belong to machining technical field, including device ontology, rotating table is equipped on the device ontology, and tooling fixture is equipped on rotating table;Tooling fixture includes installation platform, and the installation platform is connected with floating platform by ball hinge connecting mechanism, the plane where floating platform is parallel with horizontal plane, and the central position of floating platform is equipped with vacuum chuck, and multiple three-way force sensors are equipped on floating platform, and at least one group of first flutter suppression mechanism is equipped on installation platform, and first flutter suppression mechanism is connected with floating platform respectively, and first flutter suppression mechanism can inhibit the flutter generated in workpiece machining process;Central controller is equipped on installation platform, and three-way force sensor and first flutter suppression mechanism are electrically connected with central controller respectively.A kind of machining method is also disclosed.The application effectively solves the dynamic compensation mechanism in the processing of thin-walled parts through the cooperative control of three-direction flutter suppression mechanism, and effectively improves workpiece machining precision.

Description

Technical Field

[0001] This invention relates to the field of machining technology, specifically to a machining apparatus and machining method. Background Technology

[0002] In aerospace, energy equipment, and other fields, there is a growing demand for thin-walled, complex parts made of difficult-to-machine materials such as titanium alloys and high-temperature alloys. These parts are characterized by their thin walls (typically <1mm) and extremely low rigidity, making them prone to the following problems when machined under traditional rigid clamping conditions: 1. Clamping deformation: The local pressure applied by rigid fixtures can easily cause elastic deformation of the workpiece. After unloading, it will spring back, causing the workpiece's geometric accuracy to exceed the tolerance. 2. During the machining process, the workpiece will generate a certain amount of chatter. Traditional rigid fixtures cannot perform dynamic compensation and lack deep coupling with the machining process, which affects the consistency of machining and thus affects the machining accuracy. 3. Residual stress affects the part's final profile. The clamping stress of traditional rigid clamping is not fully released during the finishing stage, resulting in distortion of the part's final profile.

[0003] Therefore, the present invention mainly addresses the above-mentioned technical problems through research and improvement. Summary of the Invention

[0004] In view of the existing technical problems, the present invention provides a machining device and machining method to solve the problems in the prior art.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A machining apparatus includes an apparatus body, a rotary table on the apparatus body, and tooling fixtures on the rotary table; The tooling fixture includes a mounting platform, which is connected to a floating platform via a ball joint connection mechanism. The plane of the floating platform is parallel to the horizontal plane. A vacuum suction cup is provided at the center of the floating platform. Multiple triaxial force sensors are provided on the floating platform, which are evenly distributed along the circumference of the vacuum suction cup. At least one set of first chatter suppression mechanisms is provided on the mounting platform. The first chatter suppression mechanisms are respectively connected to the floating platform and can suppress chatter generated during workpiece processing. The mounting platform is equipped with a central controller, and the triaxial force sensor and the first flutter suppression mechanism are electrically connected to the central controller.

[0006] Preferably, the mounting platform is provided with two sets of the first flutter suppression mechanism, and the two sets of the first flutter suppression mechanism are respectively arranged along the X and Y directions of the mounting platform.

[0007] Preferably, the first flutter suppression mechanism includes a first low-friction cylinder and a first magnetorheological fluid damper arranged in a horizontal direction. The same end of the first low-friction cylinder and the first magnetorheological fluid damper are connected to the mounting platform, and the other end is connected to a connecting plate, which is fixed to the floating platform.

[0008] Preferably, a support is provided on the mounting platform near the first flutter suppression mechanism, and the same end of the first low-friction cylinder and the first magnetorheological fluid damper are connected to the support.

[0009] Preferably, the ball joint connection mechanism includes a ball joint seat disposed on the mounting platform. The ball joint seat has a hollow hemispherical structure. A ball ball support frame is floating inside the ball joint seat. A ball ball is disposed on the ball ball support frame. The ball ball support frame restricts the rotational freedom of the ball ball. The upper end of the ball ball extends out of the ball joint seat, and the portion of the ball ball extending out of the ball joint seat is embedded in the floating platform, thereby realizing the connection between the ball ball and the floating platform.

[0010] Preferably, the ball support frame includes a base, on which three support wings are evenly distributed along its circumference. The support wings have an arc-shaped structure, and the ball is supported on the three support wings. A disc spring is provided inside the ball joint seat corresponding to the position of each of the three support wings, and the outer sides of the three support wings are respectively connected to the disc springs at the corresponding positions.

[0011] Preferably, the inner side of the support wing is provided with a groove along its length, and a plurality of cross rollers are distributed in the groove along its length, with the ball bearing supported on the cross rollers.

[0012] Preferably, the mounting platform is provided with a second flutter suppression mechanism electrically connected to the central controller. The second flutter suppression mechanism includes a second low-friction cylinder and a second magnetorheological fluid damper arranged along the Z direction. The lower ends of the second low-friction cylinder and the second magnetorheological fluid damper are connected to the mounting platform, and their upper ends are connected to a support plate. The ball joint seat is fixed to the support plate.

[0013] A machining method, employing the aforementioned machining apparatus, specifically includes the following main steps: Step 1: Workpiece clamping and system initialization The workpiece to be processed is placed on the vacuum suction cup of the floating platform, so that the workpiece is adsorbed and fixed by the vacuum suction cup; the central controller calls the preset processing parameters according to the input workpiece material and geometric feature information, controls the air pressure of the first low friction cylinder and the second low friction cylinder to drop to the first preset low pressure value, and at the same time shuts off the excitation current of the first magnetorheological fluid damper and the second magnetorheological fluid damper. At this time, the system is in a low stiffness / low damping mode to ensure that the workpiece is naturally positioned without additional mechanical clamping stress. Step 2: Adaptive Multi-Stage Process Control Roughing stage: The triaxial force sensor monitors the force state of the workpiece in real time. When the force in any direction exceeds the first threshold, the central controller controls the air pressure of the first or second low-friction cylinder in the corresponding and associated directions to be increased to the second preset high pressure value. At the same time, the first preset excitation current is connected to the first or second magnetorheological fluid damper, so that the system switches to high stiffness / high damping mode to effectively suppress cutting vibration. The first threshold is the force threshold in the roughing state. Finishing stage: After roughing is completed, the central controller switches the system back to low stiffness / low damping mode: the air pressure of the first low friction cylinder or the second low friction cylinder is reduced to the third preset low pressure value, and the excitation current of the first magnetorheological fluid damper or the second magnetorheological fluid damper is significantly reduced or turned off, so as to actively release the residual stress accumulated in the workpiece during roughing. Step 3: Processing completed and system reset After finishing, the vacuum system of the vacuum chuck is first turned off. Then, the air pressure of the first and second low-friction cylinders is released, and the excitation current of the first and second magnetorheological fluid dampers is turned off. Under the action of the ball joint connection mechanism, the floating platform automatically returns to the initial position, removes the machined workpiece, and waits for the next clamping cycle.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The workpiece is fixed by vacuum adsorption during clamping, which fundamentally eliminates the local elastic deformation and clamping stress caused by rigid clamping. The system stiffness is actively released before finishing, so that the workpiece is processed in a state of near zero additional stress. This effectively avoids the final contour distortion caused by the release of residual stress and significantly improves the geometric accuracy and dimensional stability of thin-walled parts. 2. Through the coordinated control of the three-directional chatter suppression mechanism, high stiffness and high damping are used during roughing to suppress vibration and ensure stability; low stiffness and low damping are used during finishing to release stress and ensure accuracy. This adaptive capability effectively solves the dynamic compensation mechanism in the machining of thin-walled parts and effectively improves the machining accuracy of the workpiece. 3. Based on the real-time monitoring of the triaxial force sensor and the millisecond-level response characteristics of the magnetorheological fluid damper, the system can instantly sense and suppress sudden cutting chatter or impact, suppressing high-frequency fluctuations in cutting force and instantaneous deformation of the workpiece in the bud, greatly improving the dynamic stability and processing quality of the machining process. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 for Figure 1 A schematic diagram of the fixture in the diagram; Figure 3 for Figure 2 A schematic diagram of the structure after removing the floating platform; Figure 4 for Figure 3 A schematic diagram of the ball joint connection mechanism in the diagram; Figure 5 for Figure 4 A schematic diagram of the structure after removing the beads; Figure 6 for Figure 5 A schematic diagram of the ball support frame. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to experimental examples and specific embodiments. However, this should not be construed as limiting the scope of the above-mentioned subject matter of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0017] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0018] As attached Figure 1 - Appendix Figure 6 The machine tool shown includes a main body 1, a rotary table 2 mounted on the main body 1, and tooling fixtures mounted on the rotary table 2. The main body 1 can be a conventional CNC machine tool or a five-axis machining center.

[0019] For details, please refer to the following: Figure 2 and Figure 3The tooling fixture includes a mounting platform 3, which is connected to a floating platform 5 via a ball joint mechanism. The plane of the floating platform 5 is parallel to the horizontal plane. A vacuum suction cup 51 is located at the center of the floating platform 5, and the vacuum suction cup 51 is connected to a vacuum system to control its suction force. Multiple triaxial force sensors 52 are provided on the floating platform 5, and the triaxial force sensors 52 are evenly distributed along the circumference of the vacuum suction cup 51. Two sets of first chatter suppression mechanisms are provided on the mounting platform 3, respectively arranged along the X and Y directions of the mounting platform 3. A second chatter suppression mechanism is also provided on the mounting platform 3, arranged along the Z direction. The first and second chatter suppression mechanisms are respectively connected to the floating platform 5 to suppress chatter generated during workpiece processing.

[0020] The mounting platform 3 is equipped with a central controller 8. The triaxial force sensor 52 and the first and second chatter suppression mechanisms are electrically connected to the central controller 8. The central controller 8 controls the adjustment actions of the first and second chatter suppression mechanisms to suppress the chatter generated during the processing.

[0021] The first flutter suppression mechanism includes a first low-friction cylinder 61 and a first magnetorheological fluid damper 62 arranged in a horizontal direction. The same end of the first low-friction cylinder 61 and the first magnetorheological fluid damper 62 is connected to the mounting platform 3, and the other end is connected to the connecting plate 63, which is fixed on the floating platform 5.

[0022] Specifically, two supports 31 are provided on the mounting platform 3 near the first flutter suppression mechanism. The same end of the first low-friction cylinder 61 and the first magnetorheological damper 62 in the X direction are connected to the support 31 located in the X direction, and the same end of the first low-friction cylinder 61 and the first magnetorheological damper 62 in the Y direction are connected to the support 31 located in the Y direction.

[0023] The second flutter suppression mechanism includes a second low-friction cylinder 71 and a second magnetorheological fluid damper 72 arranged along the Z direction. The lower ends of the second low-friction cylinder 71 and the second magnetorheological fluid damper 72 are connected to the mounting platform 3, and their upper ends are connected to the support plate 73. The ball joint seat 41 of the ball joint connection mechanism is fixed on the support plate 73.

[0024] refer to Figure 4 , Figure 5 and Figure 6The ball joint connection mechanism includes a ball joint seat 41 embedded in the support plate 73. The ball joint seat 41 is fixedly connected to the support plate 73. The ball joint seat 41 has a hollow hemispherical structure. A ball ball support frame 44 is floating inside the ball joint seat 41. A ball ball 45 is provided on the ball ball support frame 44. The ball ball support frame 44 can restrict all rotational degrees of freedom of the ball ball 45, so that the ball ball 45 and the ball ball support frame 44 float synchronously along the ball joint seat 41. The upper end of the ball ball 45 extends out of the ball joint seat 41, and the part of the ball ball 45 extending out of the ball joint seat 41 is embedded in the floating platform 5, thereby realizing the fixed connection between the ball ball 45 and the floating platform 5.

[0025] The ball bearing support frame 44 includes a base 441 with three support wings 442 evenly distributed circumferentially. The support wings 442 have an arc-shaped structure that matches the arc shape inside the ball joint seat 41. The ball bearing 45 is supported on the inner side of the three support wings 442. Inside the ball joint seat 41, three disc springs 43 are evenly distributed circumferentially, corresponding to the positions of each support wing 442 within the ball joint seat 41. The outer sides of the three support wings 442 are connected to the corresponding disc springs 43. A pressure plate 42 is provided inside the ball joint seat 41 corresponding to each disc spring 43. One end of each disc spring 43 is connected to the inner side of the ball joint seat 41 via the pressure plate 42, and the other end is connected to the corresponding support wing 442. The presence of the disc springs 43 ensures that the ball bearing support frame 44, along with the ball bearing 45, can only float in the direction of extension and retraction of the disc springs 43. Three disc springs 43 are evenly distributed inside the ball joint seat 41. The base 441 is located at the bottom of the ball joint seat 41. The outer sides of the three support wings 442 are connected to the corresponding disc springs 43. When the force in a certain direction changes abruptly during the processing, the disc springs 43 in the corresponding range will be compressed or extended. When the workpiece and the force are removed, the ball ball support frame 44, together with the ball ball 45, can drive the floating platform 5 to return to its correct position under the action of the elastic force of the three disc springs 43.

[0026] The inner side of the support wing 442 is provided with a groove 443 along its length direction. Cross rollers 444 are distributed in the groove 443 along its length direction. The ball 45 is supported on the cross rollers 444. The cross rollers 444 can lock all rotational degrees of freedom of the ball 45, so that the ball 45 can only float in the ball joint seat 41 with the ball support frame 44.

[0027] A machining method, employing Figures 1-6 The machining apparatus shown integrates the entire process of clamping, roughing, and finishing into a multimodal adaptive control flow. Through a closed loop of monitoring, judgment, and execution, it achieves on-demand dynamic adjustment of the dynamic characteristics of the machining process. Specifically, it includes the following main steps: Step 1: Workpiece clamping and system initialization The workpiece to be processed is placed on the vacuum suction cup 51 of the floating platform 5, and the adsorption system of the vacuum suction cup 51 is activated so that the workpiece to be processed is adsorbed and fixed by the vacuum suction cup 51. The central controller 8 calls the preset processing parameters according to the input workpiece material and geometric feature information, controls the air pressure of the first low friction cylinder 61 and the second low friction cylinder 71 to drop to the first preset low pressure value (such as adjusted to 0.1~0.15MPa), and at the same time shuts off the excitation current of the first magnetorheological fluid damper 62 and the second magnetorheological fluid damper 72. At this time, the system is in a low stiffness / low damping mode to ensure that the workpiece is naturally positioned without additional mechanical clamping stress. Step 2: Adaptive Multi-Stage Process Control The processing system automatically adjusts the support stiffness and damping strength based on real-time feedback; In the roughing stage: the triaxial force sensor 52 monitors the force state of the workpiece in real time. The triaxial force sensor 52 can monitor the force state of the workpiece in the X / Y / Z directions. When the force in any direction exceeds the first threshold, the central controller 8 controls the air pressure of the first low-friction cylinder 61 or the second low-friction cylinder 71 in the corresponding and associated directions to be increased to the second preset high pressure value (e.g., adjusted to 0.4~0.5MPa). At the same time, the first preset excitation current (e.g., 0.8~1.0 T) is connected to the first magnetorheological fluid damper 62 or the second magnetorheological fluid damper 72, so that the system switches to a high stiffness / high damping mode to effectively suppress cutting vibration. The first threshold is the force threshold in each direction in the roughing state. Finishing stage: After roughing is completed, the central controller 8 switches the system back to low stiffness / low damping mode: Specifically, the air pressure of the first low friction cylinder 61 or the second low friction cylinder 71 is reduced to the third preset low pressure value, and the excitation current of the first magnetorheological fluid damper 62 or the second magnetorheological fluid damper 72 is significantly reduced or turned off, actively releasing the residual stress accumulated in the workpiece during roughing, so that the workpiece is finished under near-zero stress constraint state to ensure geometric accuracy; Millisecond-level active vibration suppression (throughout roughing and finishing): At any stage of machining, the triaxial force sensor 52 continuously monitors the high-frequency dynamics of the cutting force. When high-frequency fluctuations in the cutting force are detected and their amplitude exceeds the preset stable cutting amplitude, it is determined to be a sudden chatter. The central controller 8 responds within milliseconds (e.g., ≤5 ms) and immediately outputs a high-intensity instantaneous excitation current command to the first magnetorheological fluid damper 62 and / or the second magnetorheological fluid damper 72, so that its damping characteristics increase sharply in a very short time, actively absorb vibration energy, quickly suppress chatter, and control the chatter amplitude within an extremely small range (e.g., ≤0.01 mm). Step 3: Processing completed and system reset After finishing, the vacuum system of the vacuum chuck 51 is first turned off. Then, the air pressure of the first low-friction cylinder 61 and the second low-friction cylinder 71 is released, and the excitation current of the first magnetorheological fluid damper 62 and the second magnetorheological fluid damper 72 is turned off. Under the reset action of the disc spring 43 of the ball joint connection mechanism, the floating platform 5 automatically returns to the initial position, removes the machined workpiece, and waits for the next clamping cycle.

[0028] The preferred embodiments of the present invention have been described above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A machining apparatus, comprising an apparatus body (1), wherein a rotary table (2) is provided on the apparatus body (1), characterized in that: The rotary table (2) is equipped with tooling fixtures; The tooling fixture includes a mounting platform (3), which is connected to a floating platform (5) via a ball joint connection mechanism. The plane of the floating platform (5) is parallel to the horizontal plane. A vacuum suction cup (51) is provided at the center of the floating platform (5). Multiple triaxial force sensors (52) are provided on the floating platform (5). The triaxial force sensors (52) are evenly distributed along the circumference of the vacuum suction cup (51). A first chatter suppression mechanism is provided on the mounting platform (3). The first chatter suppression mechanism is connected to the floating platform (5). The first chatter suppression mechanism can suppress the chatter generated during the workpiece processing. The mounting platform (3) is equipped with a central controller (8), and the triaxial force sensor (52) and the first flutter suppression mechanism are electrically connected to the central controller (8); The first flutter suppression mechanism includes a first low-friction cylinder (61) and a first magnetorheological fluid damper (62) arranged in a horizontal direction. The same end of the first low-friction cylinder (61) and the first magnetorheological fluid damper (62) are connected to the mounting platform (3), and the other end is connected to the connecting plate (63), which is fixed on the floating platform (5). A support (31) is provided on the mounting platform (3) near the first flutter suppression mechanism, and the same end of the first low friction cylinder (61) and the first magnetorheological damper (62) is connected to the support (31). The mounting platform (3) is provided with a second flutter suppression mechanism electrically connected to the central controller (8). The second flutter suppression mechanism includes a second low-friction cylinder (71) and a second magnetorheological fluid damper (72) arranged along the Z direction. The lower ends of the second low-friction cylinder (71) and the second magnetorheological fluid damper (72) are connected to the mounting platform (3), and their upper ends are connected to the support plate (73). The ball joint connection mechanism is fixed on the support plate (73).

2. The machining apparatus according to claim 1, characterized in that: The mounting platform (3) is provided with two sets of the first flutter suppression mechanism, and the two sets of the first flutter suppression mechanism are respectively arranged along the X and Y directions of the mounting platform (3).

3. The machining apparatus according to claim 2, characterized in that: The ball joint connection mechanism includes a ball joint seat (41) disposed on the mounting platform (3). The ball joint seat (41) has a hollow hemispherical structure. A ball ball support frame (44) is floating inside the ball joint seat (41). A ball ball (45) is disposed on the ball ball support frame (44). The ball ball support frame (44) restricts the rotational freedom of the ball ball (45). The upper end of the ball ball (45) extends out of the ball joint seat (41), and the part of the ball ball (45) extending out of the ball joint seat (41) is embedded in the floating platform (5), thereby realizing the connection between the ball ball (45) and the floating platform (5).

4. The machining apparatus according to claim 3, characterized in that: The ball support frame (44) includes a base (441) with three support wings (442) evenly distributed around its circumference. The support wings (442) have an arc-shaped structure, and the ball (45) is supported on the three support wings (442). Disc springs (43) are provided in the ball joint seat (41) corresponding to the position of each of the support wings (442), and the outer sides of the three support wings (442) are respectively connected to the disc springs (43) at the corresponding positions.

5. The machining apparatus according to claim 4, characterized in that: The inner side of the support wing (442) is provided with a groove (443) along its length direction, and a plurality of cross rollers (444) are distributed in the groove (443) along its length direction. The ball (45) is supported on the cross rollers (444).

6. A machining method, characterized in that, The machining apparatus according to claim 5 specifically includes the following main steps: Step 1: Workpiece clamping and system initialization The workpiece to be processed is placed on the vacuum suction cup (51) of the floating platform (5), so that the workpiece to be processed is adsorbed and fixed by the vacuum suction cup (51); the central controller (8) calls the preset processing parameters according to the input workpiece material and geometric feature information, controls the air pressure of the first low friction cylinder (61) and the second low friction cylinder (71) to drop to the first preset low pressure value, and at the same time shuts off the excitation current of the first magnetorheological fluid damper (62) and the second magnetorheological fluid damper (72). At this time, the system is in a low stiffness / low damping mode to ensure that the workpiece is naturally positioned in the state of no additional mechanical clamping stress. Step 2: Adaptive Multi-Stage Process Control Rough machining stage: The triaxial force sensor (52) monitors the force state of the workpiece in real time. When the force in any direction exceeds the first threshold, the central controller (8) controls the air pressure of the first low friction cylinder (61) or the second low friction cylinder (71) in the corresponding and associated directions to be increased to the second preset high pressure value. At the same time, the first preset excitation current is connected to the first magnetorheological fluid damper (62) or the second magnetorheological fluid damper (72) to switch the system to high stiffness / high damping mode to effectively suppress cutting vibration. The first threshold is the force threshold of the rough machining state. Finishing stage: After roughing is completed, the central controller (8) switches the system back to low stiffness / low damping mode: reduces the air pressure of the first low friction cylinder (61) or the second low friction cylinder (71) to the third preset low pressure value, and significantly reduces or shuts down the excitation current of the first magnetorheological fluid damper (62) or the second magnetorheological fluid damper (72) to actively release the residual stress accumulated in the workpiece during roughing. Step 3: Processing completed and system reset After finishing, the vacuum system of the vacuum chuck (51) is turned off first. Then, the air pressure of the first low-friction cylinder (61) and the second low-friction cylinder (71) is released, and the excitation current of the first magnetorheological fluid damper (62) and the second magnetorheological fluid damper (72) is turned off. Under the action of the ball joint connection mechanism, the floating platform (5) automatically returns to the initial position, removes the processed workpiece, and waits for the next clamping cycle.

Images