Numerical control machine tool in-place measurement and on-line measurement mechanism and measurement method thereof

Abstract

The invention discloses an in-situ measurement and on-line measurement mechanism of a numerical control machine tool. The in-situ measurement and on-line measurement mechanism comprises a rack, a hinge fulcrum, a balance support, a machining shaft, a balance component, a linear guide rail, a loading actuator, an induction block and a displacement sensor. The spindle can be in a suspension state through the balance support, the influence of the machining environment can be effectively avoided, the problem of tool vibration can be effectively solved, the displacement sensor can measure the displacement value by detecting upward movement of the induction block, the measured data are fed back to a numerical control system, the system makes judgment and compensation, and therefore online measurement is achieved. The measurement method comprises the seven steps of initial preparation, suspension balance establishment, loading force setting, machining and real-time displacement monitoring, machining deviation detection, deviation compensation and procedure closed-loop completion, the problems that an existing method is poor in universality, low in measurement precision and not rigorous in compensation are solved, real-time online measurement in the machining process is achieved, and the machining precision is improved. And the machining efficiency and the product precision are improved.

Description

Technical Field

[0001] This invention relates to the field of CNC machine tool technology, and more specifically, to an in-situ measurement and online measurement mechanism and method for CNC machine tools. Background Technology

[0002] In-situ measurement on CNC machine tools is typically achieved through machine tool probes. While simple and easy to operate, this method has functional limitations. Online measurement, on the other hand, suffers from significant data fluctuations due to machine tool vibrations during machining, making data acquisition and processing extremely difficult and hindering its effective implementation. Currently, many technologies confuse in-situ measurement with online measurement. True online measurement requires real-time measurement and data feedback during machining, while existing measurement methods that mount probes on the spindle only fall under the category of in-situ or machine-based measurement.

[0003] For CNC machine tools used in grinding and polishing, grinding heads are prone to wear, dulling, and clogging, making it difficult to effectively control various variables during machining. Furthermore, these machine tools typically only allow for off-site measurement, making even in-situ measurement difficult. This not only significantly reduces machining efficiency but also introduces accuracy errors due to secondary clamping. The variables involved in machining hard and brittle materials (such as glass and ceramics) are even more critical factors affecting machining accuracy, efficiency, and surface quality. In-situ and online measurement technologies for these machine tools have yet to achieve effective breakthroughs, and related systems are currently lacking in the market.

[0004] Therefore, in view of the above situation, how to improve the measurement structure and measurement method of CNC machine tools to reduce the impact of the machining process on the measurement results and improve the measurement accuracy has become an important technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides an in-situ and online measurement mechanism for CNC machine tools. Utilizing the lever balance principle, the weight of the spindle and related structural components at one end of the balance bracket is balanced by a balancing component at the other end, allowing the spindle to remain in a suspended state. A loading actuator then applies load to the spindle, ensuring the required loading force is achieved during machining. A displacement sensor is fixedly mounted on the machine frame to monitor the spindle's vertical fluctuations in real time, thereby enabling in-situ and online measurement for CNC machine tools, especially those used for grinding and polishing hard and brittle materials. Measurement is performed simultaneously with tool machining, achieving true real-time feedback of measurement data and realizing closed-loop control of machining dimensions.

[0006] The technical solution adopted in this invention is as follows: A CNC machine tool in-situ and online measurement mechanism includes a frame, a hinge fulcrum, a balance bracket, a machining axis, a balancing component, a linear guide rail, a loading actuator, a sensing block, and a displacement sensor; the hinge fulcrum is located on the frame, and the balance bracket is connected to the hinge fulcrum; the machining axis is located at one end of the balance bracket, and the balancing component is located at the other end of the balance bracket; the linear guide rail is fixedly located on the frame, and the machining axis is connected to the linear guide rail; the loading actuator is mounted on the frame and is used to apply a loading force to the machining axis and absorb machining vibration; the sensing block is fixed on the machining axis; the displacement sensor is mounted on the side of the frame, with its detection end corresponding to the sensing block, and is used to monitor the displacement change of the sensing block; The machining axis is provided with a first limiting block, and the frame is provided with a second limiting block that cooperates with the first limiting block.

[0007] Preferably, the machining axis includes a large plate, a rotating mechanism, and a spindle. The rotating mechanism is mounted on the large plate, and the spindle is connected to the rotating mechanism. The large plate is connected to the linear guide rail, and the linear guide rail constrains the large plate to move only in the vertical direction.

[0008] Preferably, the loading actuator includes a fixed base and a loading cylinder. The fixed base is connected to the frame, and the loading cylinder is mounted on the fixed base with its piston rod facing the large plate.

[0009] Preferably, the rotating mechanism can drive the spindle to switch between vertical and horizontal postures.

[0010] Preferably, the two ends of the balance bracket are respectively provided with a first connecting bracket for connecting the machining shaft and a second connecting bracket for connecting the balance component; The first connecting bracket includes an upper pull ring, an upper pull block, a pull rod, a lower pull block, and a lower pull ring connected in sequence; the upper pull ring and the lower pull ring have the same structure and are symmetrically arranged; the upper pull block and the lower pull block have the same structure and are symmetrically arranged at both ends of the pull rod; the top of the upper pull ring is connected to the balance bracket, and a first A-shaped bracket is provided on one side of the lower part; the upper pull block has a first A-shaped groove that mates with the first A-shaped bracket, the first A-shaped groove overlaps with the first A-shaped bracket, and a stop block is provided on the outside of the first A-shaped groove to prevent the first A-shaped bracket from falling out; the lower pull ring is connected to the processing shaft; The second connecting bracket includes a hook and a rear pull ring. The hook is provided with a second A-shaped bracket, and the rear pull ring is provided with a second A-shaped groove that cooperates with the second A-shaped bracket. The second A-shaped groove overlaps with the second A-shaped bracket, and a blocking strip is provided on the outside of the second A-shaped groove to prevent the first A-shaped bracket from falling out.

[0011] Preferably, there are two hinge points, which are arranged parallel to each other. Each hinge point includes a V-groove slider, a V-groove support, and a fulcrum baffle. The bottom of the V-groove slider has a protrusion with a triangular cross-section. The V-groove support has a V-shaped groove that matches the protrusion. The fulcrum baffle is disposed on the V-groove support and is used to limit the protrusion.

[0012] Preferably, the balancing component is any one of a counterweight, a balancing cylinder, or a tension spring.

[0013] Preferably, the displacement sensor is a non-contact displacement sensor.

[0014] Preferably, it further includes a motion mechanism, the frame is connected to the motion mechanism, and the motion mechanism drives the frame to move; the motion mechanism includes, but is not limited to, CNC, six-axis robot, manipulator and multi-axis motion equipment.

[0015] A measurement method for an in-situ and online measurement mechanism of a CNC machine tool includes the following steps: S1: Initial preparation; Mount the measuring mechanism on the preset mounting surface of the CNC machine tool, six-axis robot or non-standard equipment through the frame, and complete the air and electrical connection between the mechanism and the equipment; Adjust the rotary mechanism to switch the spindle to vertical or horizontal posture according to the material and process requirements of the workpiece; Install the appropriate tool, clamp the workpiece and calibrate the workpiece datum surface, and input the preset coordinate values ​​in the CNC system; S2: Establish suspension balance; adjust according to the type of balancing component: if it is a counterweight, adjust the weight or its installation position on the balance bracket; if it is a tension spring, adjust the pretension by adjusting the screw; if it is a balancing cylinder, adjust the air supply pressure; use the lever balance principle to make the weight of the balancing component and the machining axis cancel each other out, so that the spindle is in a weightless suspension state; at the same time, adjust the piston rod of the loading actuator to the micro-tightening state, cooperate with the balancing component to maintain the initial coordinate position of the spindle, and the linear guide rail constrains the spindle to move only in the up and down direction; S3: Loading force setting; The CNC system adjusts the air supply pressure of the loading actuator through the proportional valve according to the machining process parameters, controls the extension of the piston rod, applies a downward loading force to the machining axis, and makes the tool on the spindle contact the workpiece with the set grinding or polishing force. S4: Machining and Real-time Displacement Monitoring; The machine tool machining process is started, and the spindle processes the workpiece according to the preset speed and feed rate; During the machining process, the loading actuator absorbs high-frequency vibration through the elastic buffer of compressed air, and the balancing component absorbs low-frequency vibration through elastic deformation or rigid balance; The displacement sensor captures the displacement data of the sensing block that moves synchronously with the machining axis in real time and feeds the data back to the CNC system; S5: Machining deviation detection; if the value detected by the displacement sensor does not change, the spindle is in normal machining state; if the spindle is lifted by the workpiece due to wear, dulling or blockage of the grinding head, and the value detected by the displacement sensor changes, it is determined that there is a machining deviation. S6: Deviation Compensation; The CNC system performs the following actions based on the displacement data: If the deviation of the displacement data is greater than 0 and less than or equal to the preset value, the CNC system controls the spindle to repeat the current machining toolpath; If the deviation of the displacement data is greater than the preset value, the CNC system immediately triggers an alarm and controls the spindle to pause the feed action; After the operator confirms the alarm information, the CNC system can send a command to the spindle to control the spindle to repeat the current machining toolpath, or adjust the machining parameters and restart the current machining process; S7: Process closed loop completed; when the machining process ends and the real-time displacement data remains stable and unchanged for multiple consecutive times, the CNC system controls the loading actuator to slowly unload the air supply pressure, and the spindle is reset to the initial coordinate under the action of the balancing component; the workpiece is subjected to final inspection, and after confirming that the workpiece machining parameters meet the standards, the machine tool executes the next process or stops; if the workpiece machining parameters still do not meet the standards after multiple repeated deviation compensations, the CNC system issues a grinding head replacement warning signal.

[0016] The advantages and beneficial effects of this invention are as follows: This invention adopts an indirect measurement method, connecting the machining axis and the balancing component through a balance bracket. The weight of the machining axis on one side of the balance bracket is balanced by the balancing component on the other side of the fulcrum, allowing the spindle to be in a suspended state. This effectively avoids the influence of the machining environment and solves the problem of tool vibration. The tool on the spindle system can both remove material and act as a measuring head. The displacement sensor measures the displacement value by detecting the upward movement of the sensing block and feeds the measured data back to the CNC system. The system then makes judgments and compensations, thereby realizing online measurement. In-situ measurement can be performed directly by the tool on the spindle. By detecting the position of the sensing block through the displacement sensor, in-situ measurement can be quickly achieved. This invention can realize online measurement of CNC machine tools for grinding and polishing, especially equipment for processing hard and brittle materials. The tool is measured while machining, and data is fed back in real time, realizing closed-loop control of machining dimensions. This invention has high measurement accuracy. The displacement sensor is not affected by the machining environment and vibration, and the data reliability is high. High-precision data can be obtained without additional processing. Furthermore, this invention integrates in-situ measurement and online measurement functions, sharing a single measurement system. It has a simple structure, is easy to implement, effectively solves the accuracy errors caused by secondary clamping, and improves processing efficiency and product surface quality. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a structural diagram of the in-situ and online measurement mechanism for CNC machine tools according to the present invention; Figure 2 This is another structural view of the in-situ and online measurement mechanism for CNC machine tools of the present invention; Figure 3 Bit Figure 2 Enlarged view of point A in the middle; Figure 4 This is a front view of the in-situ and online measurement mechanism for CNC machine tools according to the present invention; Figure 5 This is a side view of the in-situ and online measurement mechanism for CNC machine tools according to the present invention; Figure 6 Bit Figure 5 Enlarged view of point B in the middle; Figure 7 This is another structural view of the in-situ and online measurement mechanism for CNC machine tools of the present invention; Figure 8This is a schematic diagram of the vertical posture of the in-situ and online measurement mechanism for CNC machine tools according to the present invention; Figure 9 This is a structural diagram of the hinged fulcrum of the in-situ and online measurement mechanism for CNC machine tools according to the present invention; Figure 10 This is a cross-sectional view of the in-situ and online measurement mechanism for CNC machine tools according to the present invention; The labels in each of the attached figures are as follows: 1--Frame, 2--Hinged fulcrum, 21--V-groove slider, 21a--Protrusion, 22--V-groove support, 22a--V-groove, 23--Fulcrum baffle, 3--Balance bracket, 31--First connecting bracket, 311--Upper pull ring, 311a--First A-shaped bracket, 312--Upper pull block, 312a--First A-shaped groove, 313--Pull rod, 314--Lower pull block, 315--Lower pull ring, 316 --Stop, 32--Second connecting bracket, 321--Hook, 322--Rear pull ring, 323--Blocking bar, 4--Machining axis, 41--Large plate, 42--Rotating mechanism, 43--Spindle, 5--Balancing component, 6--Linear guide rail, 7--Loading actuator, 71--Fixed seat, 72--Loading cylinder, 8--Sensing block, 9--Displacement sensor, 10--First limit block, 11--Second limit block. Detailed Implementation

[0019] This invention discloses an in-situ and online measurement mechanism for CNC machine tools. Utilizing the lever balance principle, the weight of the spindle and related structural components at one end of the balance bracket is balanced by a balancing component at the other end, allowing the spindle to remain in a suspended state. A loading actuator then applies load to the spindle, ensuring the required loading force is achieved during machining. A displacement sensor is fixedly mounted on the machine frame to monitor the spindle's vertical fluctuations in real time, thereby enabling in-situ and online measurement for CNC machine tools, especially those used for grinding and polishing hard and brittle materials. Measurement is performed simultaneously with tool machining, achieving true real-time feedback of measurement data and realizing closed-loop control of machining dimensions.

[0020] The technical solutions of the embodiments of the present invention will be clearly and thoroughly described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Please see Figures 1 to 9This invention provides an in-situ and online measurement mechanism for CNC machine tools, comprising a frame 1, a hinge fulcrum 2, a balance support 3, a machining axis 4, a balancing component 5, a linear guide rail 6, a loading actuator 7, a sensing block 8, and a displacement sensor 9. The hinge fulcrum 2 is mounted on the frame 1, and the balance support 3 is connected to the hinge fulcrum 2. The machining axis 4 is located at one end of the balance support 3, and the balancing component 5 is located at the other end of the balance support 3. The linear guide rail 6 is fixedly mounted on the frame 1, and the machining axis 4 is connected to the linear guide rail 6. The loading actuator 7 is mounted on the frame 1 and is used to apply a loading force to the machining axis 4 and absorb machining vibrations. The sensing block 8 is fixed to the machining axis 4. The displacement sensor 9 is mounted on the side of the frame 1, with its detection end corresponding to the sensing block 8, and is used to monitor the displacement change of the sensing block 8. A first limiting block is provided on the machining axis, and a second limiting block that cooperates with the first limiting block is provided on the frame.

[0022] In this embodiment of the invention, the hinge fulcrum 2 is installed on the top of the frame 1, and the middle part of the balance bracket 3 is connected to the hinge fulcrum 2. The frame 1, the balance bracket 3, and the hinge bracket together form a lever structure. The machining shaft 4 is installed at one end of the balance bracket 3, and the balancing component 5 is installed at the other end of the balance bracket 3. The weight of the machining shaft 4 is offset by the lever balance principle, so that the machining shaft 4 is in a suspended state. The linear guide rail 6 is vertically fixed to the frame 1. The machining shaft 4 and the linear guide rail 6 are slidably engaged by a slider to ensure that the entire machining shaft 4 can only move vertically along the outside of the frame 1, avoiding lateral deviation. The loading actuator 7 is installed on the outer surface of the frame 1, and its output end is correspondingly set with the machining shaft 4. It can accurately adjust the loading force according to the processing requirements, and at the same time absorb the vibration generated during the processing to ensure the stability of the measurement environment. The sensing block 8 is fixed on the machining axis 4, and the displacement sensor 9 is installed on the frame 1 and is vertically opposite to the sensing block 8. When the tool on the machining axis 4 contacts the workpiece and causes displacement, the sensing block 8 moves synchronously with the machining axis 4. The displacement sensor 9 can capture the displacement data of the machining axis 4 in real time and feed it back to the CNC system by detecting the position of the sensing block 8.

[0023] A first limiting block 10 is provided on the machining axis 4, and a second limiting block 11 that cooperates with the first limiting block 10 is provided on the frame 1. Whether the loading actuator 7 is in a loaded or unloaded state, the machining axis 4 moves downwards under its own weight, causing the first limiting block 10 to contact the second limiting block 11, thereby limiting the downward movement of the machining axis 4. Only when there is excess material in the machining process will the machining axis 4 be lifted, and the first limiting block 10 will separate from the second limiting block 11. The displacement sensor 9 can then detect this displacement change. Furthermore, the connection between the second limiting block 11 and the frame 1 is a detachable and replaceable structure, and the top of the second limiting block 11 is an arc-shaped surface that contacts the bottom of the first limiting block 10. The arc-shaped surface contacts the plane via a line or point contact, providing an automatic centering effect. Even with slight installation errors, the arc-shaped surface can guide the first limiting block 10 to slide along the arc-shaped surface to the correct limiting position, reducing machining and assembly accuracy requirements and improving production efficiency.

[0024] During online measurement, when the grinding head becomes worn, dull, or clogged, the grinding force of the tool decreases, and the feed rate cannot remove the workpiece material in time. The workpiece will generate a reaction force on the tool, lifting the machining axis 4 upwards, which in turn moves the sensing block 8 upwards synchronously. The displacement sensor 9, fixed on the frame 1, captures the displacement of the sensing block 8 in real time and feeds the data back to the CNC system. The system determines the lifting amount of the machining axis 4 based on the preset coordinate values.

[0025] When only in-situ measurement is required, the tool on machining axis 4 can be used directly for measurement, or a purely mechanical probe can be replaced to replace the tool, and the workpiece can be measured through the same displacement monitoring principle.

[0026] It should be noted that the balancing component 5 in this embodiment can be an adjustable weight counterweight device. In other embodiments, a cylinder or spring can be used instead of a weight counterweight device, as long as the weight balance at both ends of the balancing bracket 3 can be achieved, it falls within the protection scope of this invention. Furthermore, the displacement sensor 9 is a laser displacement sensor 9, with a measurement accuracy down to the micrometer level. In other embodiments, other types of non-contact displacement sensors 9 can also be used, as long as the measurement accuracy requirements are met.

[0027] In this embodiment, the frame 1 can be made of high-strength aluminum alloy, which is lightweight and rigid. It can be bolted to the worktable of a CNC machine tool, the end effector of a six-axis robot, or other non-standard processing equipment to adapt to different processing scenarios.

[0028] Preferably, the machining axis 4 includes a large plate 41, a rotating mechanism 42, and a spindle 43. The rotating mechanism 42 is mounted on the large plate 41, and the spindle 43 is connected to the rotating mechanism 42. The large plate 41 is connected to the linear guide rail 6, and the linear guide rail 6 constrains the large plate 41 to move only in the up and down direction.

[0029] In this embodiment, the large plate 41 adopts an integral molding or high-strength splicing structure, which has sufficient bending and torsional rigidity and can bear the weight of the rotating mechanism 42, the spindle 43 and the cutting tool as well as the machining load. When the loading actuator 7 applies force or the workpiece reaction force acts on the large plate 41, the large plate 41 synchronously transmits the force to the rotating mechanism 42 and the spindle 43.

[0030] Thanks to the larger area of ​​the large plate 41, more installation space is reserved on the back, accommodating the linear guide 6 with greater rigidity and a larger load-bearing area. Furthermore, the linear guide 6 in this embodiment includes a pair of parallel crossed roller guide slides. The crossed roller guide slide is a high-precision linear motion guiding device, its core feature being the use of cylindrical rollers arranged at 90° intervals as rolling elements. Compared to traditional ball bearing guides or sliding guides, it has a larger load-bearing area and greater rigidity, effectively resisting off-center loads, torque loads, and vibrations, making it suitable for applications requiring high stability. The base of the crossed roller guide slide is connected to the frame 1, and the slider is connected to the large plate 41, allowing the large plate 41 and the frame 1 to slide relative to each other in the vertical direction.

[0031] Preferably, the loading actuator 7 includes a fixed base 71 and a loading cylinder 72. The fixed base 71 is connected to the frame 1, and the loading cylinder 72 is mounted on the fixed base 71 with its piston rod facing the large plate 41.

[0032] In this embodiment, when the loading cylinder 72 is used as the loading actuator 7, its piston rod is not connected to the large plate 41. Instead, the extension of the piston rod is used to press the large plate 41 down. Specifically, in the initial state, the piston rod of the loading cylinder 72 is in a slightly extended or pre-tightened state, without applying additional loading force. It only works with the balance bracket 3 to maintain the initial position of the spindle 43. At this time, the linear guide 6 constrains the spindle 43 to move only in the up and down direction, ensuring the accuracy of displacement monitoring. During the machining stage, the CNC system sets the loading force parameters according to the machining process (such as grinding or polishing of hard and brittle materials). By adjusting the air supply pressure of the loading cylinder 72, the extension of the piston rod is controlled, thereby applying downward pressure to the large plate 41. This force is transmitted to the spindle 43 through the large plate 41 and the rotating mechanism 42, causing the tool on the output end of the spindle 43 to contact the workpiece with the set grinding / polishing force. During the machining process, factors such as wear of the machine tool grinding head and impact of hard points on the workpiece will cause vibration, which will lead to fluctuations in the measurement data. At this point, the pneumatic buffering characteristic of the loading cylinder 72 comes into play. The compressed air inside the cylinder can be slowly released and replenished through the throttle valve. When the spindle 43 experiences a slight displacement due to vibration, the cylinder piston rod will adaptively extend and retract with the slight movement of the large plate 41. The elastic buffering of the compressed air absorbs the vibration energy, preventing the vibration from being transmitted to the monitoring end of the displacement sensor 9. Because this vibration absorption process ensures that the displacement of the spindle 43 is determined only by the actual contact state between the tool and the workpiece, rather than by vibration interference, it can ensure that the data collected by the displacement sensor 9 has no vibration peaks, requiring no additional processing, reducing the system burden and avoiding interference with accuracy.

[0033] This embodiment uses pneumatic loading, which uses pneumatic components such as pressure reducing valves and proportional valves to precisely adjust the air pressure, thereby quickly and accurately changing the output force of the cylinder to adapt to the loading force requirements of different materials and processing procedures.

[0034] Preferably, the rotating mechanism 42 can drive the spindle 43 to switch between vertical and horizontal postures. In this embodiment, the rotating mechanism 42 is connected to the spindle 43, and through the drive of the rotating mechanism 42, the spindle 43 can be switched to a horizontal posture to adapt to different processing scenarios. Figure 8 As shown, the spindle 43 is in a vertical position in this state.

[0035] Preferably, the two ends of the balance bracket 3 are respectively provided with a first connecting bracket 31 for connecting the processing shaft 4 and a second connecting bracket 32 ​​for connecting the balance component 5; The first connecting bracket 31 includes an upper pull ring 311, an upper pull block 312, a pull rod 313, a lower pull block 314, and a lower pull ring 315 connected in sequence. The upper pull ring 311 and the lower pull ring 315 have the same structure and are symmetrically arranged. The upper pull block 312 and the lower pull block 314 have the same structure and are symmetrically arranged at both ends of the pull rod 313. The top of the upper pull ring 311 is connected to the balance bracket 3, and a first A-shaped bracket 311a is provided on one side of the lower part. The upper pull block 312 has a first A-shaped groove 312a that cooperates with the first A-shaped bracket 311a. The first A-shaped groove 312a overlaps with the first A-shaped bracket 311a, and a stop block 316 is provided on the outside of the first A-shaped groove 312a to prevent the first A-shaped bracket 311a from falling out. The lower pull ring 315 is connected to the processing shaft 4. The second connecting bracket 32 ​​includes a hook 321 and a rear pull ring 322. The hook 321 is provided with a second A-shaped bracket, and the rear pull ring 322 is provided with a second A-shaped groove that cooperates with the second A-shaped bracket. The second A-shaped groove overlaps with the second A-shaped bracket, and a blocking strip 323 is provided on the outside of the second A-shaped groove to prevent the first A-shaped bracket 311a from falling out.

[0036] In this embodiment, the first A-shaped bracket 311a and the first A-shaped groove 312a of the first connecting bracket 31, and the second A-shaped bracket and the second A-shaped groove of the second connecting bracket 32, all adopt a wedge-fit structure design. Because the inclined surface of the A-shaped structure has an automatic centering function, the A-shaped bracket can adaptively adjust its position along the inclined surface of the A-shaped groove during assembly, ensuring that the tip of the A-shaped bracket is precisely aligned with the A-shaped groove, avoiding lever arm offset due to installation deviation. This centering characteristic directly ensures that the force center points of the machining shaft 4 and the balancing component 5 are collinear, making the lever balance principle effectively implemented and greatly improving the stability of the main shaft 43 in its suspended state. The inclined surface of the A-shaped structure has a slight elastic redundancy, which can absorb micro-vibrations during machining, avoiding thread loosening or pin wear caused by vibration. Compared with traditional rigid connections, such as bolt tightening and pin insertion, this structure can reduce the problem of increased connection gaps caused by vibration transmission, ensuring the long-term stability of the lever arm. Furthermore, the stop 316 of the first connecting bracket 31 and the blocking strip 323 of the second connecting bracket 32 ​​respectively form an "outer limit" for the A-shaped bracket, which, together with the "inner inclined surface self-locking" of the A-shaped structure, forms a double anti-detachment mechanism. During the processing, even when faced with instantaneous impact loads (such as collisions with hard points on the workpiece) or high-frequency vibrations, the A-shaped bracket will not detach from the A-shaped groove, completely avoiding safety hazards such as the spindle 43 falling or imbalance caused by connection failure, and ensuring the continuity of the processing and measurement process.

[0037] Preferably, there are two hinge points 2, which are arranged parallel to each other. Each hinge point 2 includes a V-groove slider 21, a V-groove support 22, and a fulcrum baffle 23. The bottom of the V-groove slider 21 has a protrusion 21a with a triangular cross-section. The V-groove support 22 has a V-groove 22a that mates with the protrusion 21a. The fulcrum baffle 23 is located on the V-groove support 22 and is used to limit the protrusion 21a. In this embodiment, the two parallel hinge points 2 form a "dual-axis positioning", allowing only the balance bracket 3 to rotate around the fulcrum, completely restricting unnecessary degrees of freedom such as lateral movement and torsion. The two fulcrums evenly distribute the combined load of the balance bracket 3, the machining shaft 4, and the balance component 5, which helps to reduce local stress concentration. Especially under high-frequency vibration and instantaneous impact loads, the two fulcrums can avoid deformation or wear of a single fulcrum, extend the service life of the hinge structure, and ensure the accuracy and stability of long-term use. The triangular protrusion 21a of the V-groove slider 21 and the V-groove 22a of the V-groove support 22 are in a "wedge-shaped fit". Utilizing the inclined guiding characteristics of the V-shaped structure, the protrusion 21a can adaptively adjust its position along the V-groove 22a during assembly, achieving automatic centering. This ensures that the axes of the two hinged fulcrums 2 are strictly parallel and collinear with the force transmission center of the balance bracket 3. Even minor machining or installation errors can be offset by the V-shaped fit, significantly reducing assembly difficulty. The fulcrum baffle 23 is fixed to the V-groove support 22, providing axial and radial double restraint for the triangular protrusion 21a. This prevents the protrusion 21a from dislodging from the V-groove 22a due to instantaneous impacts (such as collisions with hard points on the workpiece) or vibrations during machining, thoroughly ensuring the operational safety of the lever mechanism and preventing the main shaft 43 from falling or becoming unbalanced.

[0038] Preferably, the balancing component 5 is any one of a counterweight, a balancing cylinder, or a tension spring. In this embodiment, the structure of the balancing component 5 can be selected according to different processing requirements and equipment conditions. For example, a counterweight is suitable for scenarios where the spindle 43 system has a fixed self-weight and stable processing conditions. It has a simple structure, high static balance accuracy, requires no additional power source, and has the lowest cost. A balancing cylinder is suitable for scenarios where the load on the spindle 43 changes dynamically, such as switching between multiple workpiece specifications or gradient loading of processes. It can adjust the balancing force in real time through air pressure to quickly compensate for load fluctuations, taking into account both balance accuracy and dynamic adaptability. A tension spring is suitable for lightweight spindle 43 or high-frequency micro-vibration conditions. Its elastic characteristics can help absorb low-frequency vibrations. At the same time, it has a compact structure, no additional energy consumption, and is suitable for equipment installation scenarios with limited space. The three types can be flexibly selected according to the weight of the processing axis 4, the stability of the working conditions, and the equipment configuration. There is no need to modify the core structure such as the balancing bracket 3 and the connecting bracket. The adaptability covers common online measurement scenarios of CNC machine tools.

[0039] The counterweights, balancing cylinders, or tension springs listed in this embodiment can all achieve the purpose of balancing the weight of the main shaft 43. This modified design is based on the fundamental principle of this invention, only the method of achieving balance is slightly different, and it must be included within the scope of protection of this invention.

[0040] Preferably, the displacement sensor 9 is a non-contact displacement sensor 9.

[0041] Preferably, the device further includes a motion mechanism, with the frame 1 connected to the motion mechanism, which drives the frame 1 to move. The motion mechanism includes, but is not limited to, CNC machines, six-axis robots, robotic arms, and multi-axis motion devices. In this embodiment, the frame 1 can quickly interface with various motion devices through standardized interfaces, such as flanges or T-slots. Enterprises do not need to replace existing core equipment such as CNC machines and robots; they only need to add the measurement mechanism of this invention to upgrade the online measurement function, significantly reducing the modification cycle, improving equipment reuse rate, and effectively reducing the cost of technology implementation.

[0042] A measurement method for an in-situ and online measurement mechanism of a CNC machine tool includes the following steps: S1: Initial preparation; Mount the measuring mechanism on the preset mounting surface of the CNC machine tool, six-axis robot or non-standard equipment through the frame, and complete the air and electrical connection between the mechanism and the equipment; Adjust the rotary mechanism to switch the spindle to vertical or horizontal posture according to the material and process requirements of the workpiece; Install the appropriate tool, clamp the workpiece and calibrate the workpiece datum surface, and input the preset coordinate values ​​in the CNC system; S2: Establish suspension balance; adjust according to the type of balancing component: if it is a counterweight, adjust the weight or its installation position on the balance bracket; if it is a tension spring, adjust the pretension by adjusting the screw; if it is a balancing cylinder, adjust the air supply pressure; use the lever balance principle to make the weight of the balancing component and the machining axis cancel each other out, so that the spindle is in a weightless suspension state; at the same time, adjust the piston rod of the loading actuator to the micro-tightening state, cooperate with the balancing component to maintain the initial coordinate position of the spindle, and the linear guide rail constrains the spindle to move only in the up and down direction; S3: Loading force setting; The CNC system adjusts the air supply pressure of the loading actuator through the proportional valve according to the machining process parameters, controls the extension of the piston rod, applies a downward loading force to the machining axis, and makes the tool on the spindle contact the workpiece with the set grinding or polishing force. S4: Machining and Real-time Displacement Monitoring; The machine tool machining process is started, and the spindle processes the workpiece according to the preset speed and feed rate; During the machining process, the loading actuator absorbs high-frequency vibration through the elastic buffer of compressed air, and the balancing component absorbs low-frequency vibration through elastic deformation or rigid balance; The displacement sensor captures the displacement data of the sensing block that moves synchronously with the machining axis in real time and feeds the data back to the CNC system; S5: Machining deviation detection; if the value detected by the displacement sensor does not change, the spindle is in normal machining state; if the spindle is lifted by the workpiece due to wear, dulling or blockage of the grinding head, and the value detected by the displacement sensor changes, it is determined that there is a machining deviation. S6: Deviation Compensation; The CNC system performs the following actions based on the displacement data: If the deviation of the displacement data is greater than 0 and less than or equal to the preset value, the CNC system controls the spindle to repeat the current machining toolpath; If the deviation of the displacement data is greater than the preset value, the CNC system immediately triggers an alarm and controls the spindle to pause the feed action; After the operator confirms the alarm information, the CNC system can send a command to the spindle to control the spindle to repeat the current machining toolpath, or adjust the machining parameters and restart the current machining process; S7: Process closed loop completed; when the machining process ends and the real-time displacement data remains stable and unchanged for multiple consecutive times, the CNC system controls the loading actuator to slowly unload the air supply pressure, and the spindle is reset to the initial coordinate under the action of the balancing component; the workpiece is subjected to final inspection, and after confirming that the workpiece machining parameters meet the standards, the machine tool executes the next process or stops; if the workpiece machining parameters still do not meet the standards after multiple repeated deviation compensations, the CNC system issues a grinding head replacement warning signal.

[0043] This measurement method comprises seven steps: initial preparation, establishing suspension balance, setting the loading force, machining and real-time displacement monitoring, machining deviation detection, deviation compensation, and closed-loop completion of the process. It is compatible with various balancing components such as counterweights, tension springs, and balancing cylinders. The loading force is precisely controlled through leverage ratios, and the dual vibration absorption characteristics of the loading actuator and balancing components ensure stable measurement data. Continuous sampling is used to determine deviations, and a closed-loop error compensation mechanism is implemented. A tool change warning function is also provided. This measurement method solves the problems of poor versatility, low measurement accuracy, and imprecise compensation in existing methods. It achieves real-time online measurement during the machining process, improving machining efficiency and product accuracy. The operation is standardized and easy to implement. The online measurement method of this invention will be described in detail below using a hard and brittle material machining scenario.

[0044] Initial preparation: Mount the measuring mechanism onto the end effector of the six-axis robot via a frame, and complete the connection of the air circuit (cylinder-proportional valve-air compressor) and electrical circuit (displacement sensor-CNC system-robot controller). Based on the horizontal machining requirements of the workpiece, adjust the rotary mechanism to switch the spindle to a horizontal position and secure it with locking pins. Install the cutting tool, clamp the workpiece onto the worktable using a fixture, and use the cutting tool on the spindle to lightly touch the workpiece end face to complete the benchmark calibration; input the preset coordinate values ​​into the CNC system.

[0045] Establish floating balance; the balance component uses counterweight blocks. By adjusting the weight of the counterweight blocks, the self-weight of the machining shaft can be completely offset. Detect the floating state of the machining shaft. When there is no external force, the main shaft can freely displace in the up and down directions and remain without deviation after a certain period of time, then it is determined that the floating is qualified. Adjust the piston rod of the loading cylinder to the micro-shrinking pre-tightening state, and cooperate with the counterweight block to maintain the initial coordinates of the main shaft. The linear guide restricts the main shaft to move only in the horizontal up and down directions.

[0046] Loading force setting; the numerical control system adjusts the air supply pressure of the loading cylinder through the proportional valve. The piston rod extends to apply a thrust to the balance bracket. After being transmitted by the large plate, the cutting tool on the main shaft smoothly contacts the surface of the workpiece.

[0047] Machining and real-time displacement monitoring; start the six-axis robot to drive the measuring mechanism and perform machining on the workpiece according to the preset path; during the machining process, the high-frequency vibration generated by the rotation of the cutting tool is buffered and absorbed by the compressed air in the loading cylinder, and the low-frequency vibration generated by the movement of the robot is absorbed by the elastic deformation of the tension spring. The laser displacement sensor captures the displacement data of the induction block in real-time at the sampling frequency and feeds it back to the numerical control system in real-time.

[0048] Machining deviation detection; in an ideal state, the value detected by the displacement sensor does not change, that is, the detected displacement deviation amount is 0. During the actual machining process, after a specified machining time, if the displacement data sampled continuously by the numerical control system changes, it is determined that there is a machining deviation. For example, the slight dulling of the grinding head causes the grinding force to decrease, resulting in the main shaft being lifted by the machined material.

[0049] Deviation compensation; the offset amount of the real-time displacement data of the numerical control system, that is, the amount by which the machining shaft is lifted; if the deviation amount of the displacement data is greater than 0 and less than or equal to the preset value: the numerical control system does not adjust the loading force of the loading actuator and directly controls the main shaft to repeat the current machining tool path; if the deviation amount of the displacement data is greater than the preset value, the numerical control system immediately triggers an alarm prompt, which can be accompanied by an audible and visual alarm signal, and controls the main shaft to pause the feeding action; after the operator confirms the alarm information, an instruction can be sent to the main shaft through the numerical control system to control the main shaft to repeat the current machining tool path or restart the current machining process after adjusting the machining parameters; Completion of the process closed-loop; after the rough grinding process is completed, the displacement data is continuously stable within the preset range for multiple times. The numerical control system controls the loading cylinder to slowly unload the air supply pressure, and the main shaft resets to the initial coordinates under the action of the counterweight block. If the displacement data still fails to meet the standard after multiple deviation compensations during the machining process, the system will issue a warning signal of "the grinding head is dull, it is recommended to replace" and pause the machining.

[0050] The advantages and beneficial effects of this invention are as follows: This invention adopts an indirect measurement method, connecting the machining axis and the balancing component through a balance bracket. The weight of the machining axis on one side of the balance bracket is balanced by the balancing component on the other side of the fulcrum, allowing the spindle to be in a suspended state. This effectively avoids the influence of the machining environment and solves the problem of tool vibration. The tool on the spindle system can both remove material and act as a measuring head. The displacement sensor measures the displacement value by detecting the upward movement of the sensing block and feeds the measured data back to the CNC system. The system then makes judgments and compensations, thereby realizing online measurement. In-situ measurement can be performed directly by the tool on the spindle. By detecting the position of the sensing block through the displacement sensor, in-situ measurement can be quickly achieved. This invention can realize online measurement of CNC machine tools for grinding and polishing, especially equipment for processing hard and brittle materials. The tool is measured while machining, and data is fed back in real time, realizing closed-loop control of machining dimensions. This invention has high measurement accuracy. The displacement sensor is not affected by the machining environment and vibration, and the data reliability is high. High-precision data can be obtained without additional processing. Furthermore, this invention integrates in-situ measurement and online measurement functions, sharing a single measurement system. It has a simple structure, is easy to implement, effectively solves the accuracy errors caused by secondary clamping, and improves processing efficiency and product surface quality.

[0051] The foregoing has provided a detailed description of the in-situ and online measurement mechanism and method for CNC machine tools provided by the present invention. For those skilled in the art, based on the ideas of the embodiments of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A mechanism for in-situ and online measurement of CNC machine tools, characterized in that, The system includes a frame (1), a hinge point (2), a balance bracket (3), a machining axis (4), a balancing component (5), a linear guide rail (6), a loading actuator (7), a sensing block (8), and a displacement sensor (9). The hinge point is located on the frame, and the balance bracket is connected to the hinge point. The machining axis is located at one end of the balance bracket, and the balancing component is located at the other end of the balance bracket. The linear guide rail is fixedly located on the frame, and the machining axis is connected to the linear guide rail. The loading actuator is installed on the frame and is used to apply a loading force to the machining axis and absorb machining vibrations. The sensing block is fixed on the machining axis. The displacement sensor is installed on the side of the frame, with its detection end corresponding to the sensing block, and is used to monitor the displacement change of the sensing block. The machining axis is provided with a first limiting block (10), and the frame is provided with a second limiting block (11) that cooperates with the first limiting block.

2. The in-situ and online measurement mechanism for CNC machine tools according to claim 1, characterized in that, The machining axis includes a large plate (41), a rotating mechanism (42), and a spindle (43). The rotating mechanism is mounted on the large plate, and the spindle is connected to the rotating mechanism. The large plate is connected to the linear guide rail, and the linear guide rail constrains the large plate to move only in the up and down direction.

3. The in-situ and online measurement mechanism for CNC machine tools according to claim 2, characterized in that, The loading actuator includes a fixed base (71) and a loading cylinder (72). The fixed base is connected to the frame, and the loading cylinder is mounted on the fixed base with its piston rod facing the large plate.

4. The in-situ and online measurement mechanism for CNC machine tools according to claim 2, characterized in that, The rotating mechanism can drive the spindle to switch between vertical and horizontal positions.

5. The in-situ and online measurement mechanism for CNC machine tools according to claim 1, characterized in that, The balance bracket is provided with a first connecting bracket (31) for connecting the machining shaft and a second connecting bracket (32) for connecting the balance component at both ends. The first connecting bracket includes an upper pull ring (311), an upper pull block (312), a pull rod (313), a lower pull block (314), and a lower pull ring (315) connected in sequence; the upper pull ring and the lower pull ring have the same structure and are symmetrically arranged; the upper pull block and the lower pull block have the same structure and are symmetrically arranged at both ends of the pull rod; the top of the upper pull ring is connected to the balance bracket, and a first A-shaped bracket (311a) is provided on one side of the lower part; the upper pull block has a first A-shaped groove (312a) that cooperates with the first A-shaped bracket, the first A-shaped groove overlaps with the first A-shaped bracket, and a stop block (316) is provided on the outside of the first A-shaped groove to prevent the first A-shaped bracket from falling out; the lower pull ring is connected to the processing shaft; The second connecting bracket includes a hook (321) and a rear pull ring (322). The hook is provided with a second A-shaped bracket, and the rear pull ring is provided with a second A-shaped groove that cooperates with the second A-shaped bracket. The second A-shaped groove overlaps with the second A-shaped bracket, and a blocking strip (323) is provided on the outside of the second A-shaped groove to prevent the first A-shaped bracket from coming off.

6. The in-situ and online measurement mechanism for CNC machine tools according to claim 1, characterized in that, The number of hinge points is two, and the two hinge points are arranged parallel to each other; the hinge point includes a V-groove slider (21), a V-groove support (22) and a fulcrum baffle (23); the bottom of the V-groove slider is provided with a protrusion (21a) with a triangular cross section, the V-groove support is provided with a V-shaped groove (22a) that cooperates with the protrusion, and the fulcrum baffle is provided on the V-groove support and is used to limit the protrusion.

7. The in-situ and online measurement mechanism for CNC machine tools according to claim 1, characterized in that, The balancing component is any one of a counterweight, a balancing cylinder, or a tension spring.

8. The in-situ and online measurement mechanism for CNC machine tools according to claim 1, characterized in that, The displacement sensor is a non-contact displacement sensor.

9. The in-situ and online measurement mechanism for CNC machine tools according to claim 1, characterized in that, It also includes a motion mechanism, the frame is connected to the motion mechanism, and the motion mechanism drives the frame to move; the motion mechanism includes, but is not limited to, CNC, six-axis robot, manipulator and multi-axis motion equipment.

10. A measurement method for an in-situ and online measurement mechanism for a CNC machine tool, using the in-situ and online measurement mechanism for a CNC machine tool as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1: Initial preparation; Mount the measuring mechanism on the preset mounting surface of the CNC machine tool, six-axis robot or non-standard equipment through the frame, and complete the air circuit and electrical circuit connection between the mechanism and the equipment; Adjust the rotating mechanism to switch the spindle to a vertical or horizontal posture according to the material and process requirements of the workpiece. Install the appropriate cutting tool, clamp the workpiece and calibrate the workpiece datum surface, and input the preset coordinate values ​​in the CNC system; S2: Establish suspension equilibrium; Adjustments are made according to the type of balancing component: if it is a counterweight, adjust the weight or its installation position on the balancing bracket; if it is a tension spring, adjust the pretension by adjusting the screw; if it is a balancing cylinder, adjust the air supply pressure. The lever balance principle is used to make the weight of the balancing component and the machining axis cancel each other out, so that the spindle is in a weightless floating state; at the same time, the piston rod of the loading actuator is adjusted to a micro-tightening state, which works with the balancing component to maintain the initial coordinate position of the spindle, and the linear guide rail constrains the spindle to move only in the up and down direction. S3: Loading force setting; The CNC system adjusts the air supply pressure of the loading actuator through the proportional valve according to the machining process parameters, controls the extension of the piston rod, applies a downward loading force to the machining axis, and makes the tool on the spindle contact the workpiece with the set grinding or polishing force. S4: Machining and Real-time Displacement Monitoring; The machine tool machining process is started, and the spindle processes the workpiece at the preset speed and feed rate. During the machining process, the loading actuator absorbs high-frequency vibration through the elastic buffer of compressed air, and the balancing component absorbs low-frequency vibration through elastic deformation or rigid balancing. The displacement sensor captures the displacement data of the sensing block that moves synchronously with the machining axis in real time and feeds the data back to the CNC system. S5: Machining deviation detection; if the value detected by the displacement sensor does not change, the spindle is in normal machining state; if the spindle is lifted by the workpiece due to wear, dulling or blockage of the grinding head, and the value detected by the displacement sensor changes, it is determined that there is a machining deviation. S6: Deviation Compensation; The CNC system performs the following actions based on the displacement data: If the deviation of the displacement data is greater than 0 and less than or equal to the preset value, the CNC system controls the spindle to repeat the current machining toolpath; If the deviation of the displacement data is greater than the preset value, the CNC system immediately triggers an alarm and controls the spindle to pause the feed action; After the operator confirms the alarm information, the CNC system can send a command to the spindle to control the spindle to repeat the current machining toolpath, or adjust the machining parameters and restart the current machining process; S7: Process closed loop completed; when the machining process ends and the real-time displacement data remains stable and unchanged for multiple consecutive times, the CNC system controls the loading actuator to slowly unload the air supply pressure, and the spindle is reset to the initial coordinates under the action of the balancing component. After performing a final inspection on the workpiece and confirming that the workpiece processing parameters meet the standards, the machine tool will proceed to the next process or stop. If the workpiece processing parameters still do not meet the standards after repeated deviation compensation, the CNC system will issue a warning signal for replacing the grinding head.

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