Numerical control machine precision correction device and correction method

Abstract

This invention discloses a precision calibration device and method for CNC machine tools. The device includes a lower mounting structure, a first power mechanism, an upper mounting structure, a second power mechanism, and a calibration rod. The lower mounting structure includes an adjustable base, a mounting seat, and a rotary seat. The first power mechanism is installed in the lower mounting cavity formed by the adjustable base, mounting seat, and rotary seat, and a first monitoring unit is disposed in the lower mounting cavity. The second power mechanism is installed in the upper mounting cavity of the upper mounting structure, and the bottom of the calibration rod is connected to the second power mechanism via a transmission connection. A second monitoring unit is disposed in the upper mounting cavity. This invention provides a measurement reference for a dial indicator. The first power mechanism drives the calibration rod to rotate horizontally, and the second power mechanism drives the calibration rod to swing up and down around its bottom. The first and second monitoring units are used to monitor the rotation angle and swing angle, accurately determine the position of the calibration rod, and thus realize the precision measurement of each axis and the worktable of the CNC machine tool, improving calibration efficiency and accuracy.

Description

Technical Field

[0001] This invention relates to the field of CNC machine tool accuracy correction, and in particular to a CNC machine tool accuracy correction device and correction method. Background Technology

[0002] Large CNC machine tools establish relative coordinates for each moving axis based on the worktable. Simultaneously, semi-closed or closed-loop detection positions are established on each axis using linear encoders to ensure machining accuracy. During operation, factors such as machining forces, foundation settlement, machine tool relocation, and external collisions cause irregular changes in the machine tool's axes relative to the worktable plane and center. These irregular changes lead to decreased machining accuracy and even product scrap. Therefore, regular or irregular accuracy calibration of each moving axis is crucial. Currently, CNC machine tool calibration mainly relies on single tools such as spirit levels, dihedrals, and right-angle rulers. The calibration process requires the coordination of these measuring tools, making operation cumbersome, resulting in large measurement errors, incomplete calibration, and unsatisfactory calibration effects, still impacting machining accuracy. Summary of the Invention

[0003] In view of this, the first objective of the present invention is to provide a CNC machine tool accuracy correction device, and the second objective of the present invention is to provide a CNC machine tool accuracy correction method.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: The CNC machine tool precision correction device of the present invention includes a lower mounting structure, a first power mechanism, an upper mounting structure, a second power mechanism, and a calibration rod driven by the second power mechanism; The lower mounting structure includes an adjustable base, a mounting seat disposed on the adjustable base, and a rotary seat disposed on the mounting seat. The first power mechanism is installed in the lower mounting cavity formed by the adjustable base, the mounting seat, and the rotary seat. A first monitoring unit for monitoring the position of the rotary seat is provided in the lower mounting cavity. The upper mounting structure is mounted on the rotary seat. The upper mounting structure has an upper mounting cavity. The second power mechanism is installed in the upper mounting cavity. The bottom of the calibration rod is connected to the second power mechanism. An adjustment hole that mates with the calibration rod is provided on the top plate of the upper mounting structure. A second monitoring unit for monitoring the position of the calibration rod is provided in the upper mounting cavity. The signal output terminals of the first monitoring unit and the second monitoring unit are both connected to the signal input terminal of the controller, and the display signal output terminal of the controller is connected to the signal input terminal of the display screen.

[0005] The beneficial effects are as follows: The calibration rod of the present invention provides a measurement reference for the dial indicator. The first power mechanism can drive the calibration rod to rotate horizontally through the rotary seat to adjust the position of the measurement reference. The second power mechanism can drive the calibration rod to swing up and down with its bottom as the center. The first monitoring unit and the second monitoring unit are respectively used to monitor the rotation angle of the rotary seat and the swing angle of the calibration rod, so as to accurately determine the position of the calibration rod and ensure the accuracy of the measurement reference. By using the present invention in combination with a dial indicator, the accuracy measurement of each axis of the CNC machine tool (it can be measured for a single axis, or combined for two-axis linkage measurement, or three-axis linkage measurement) and the workbench can be realized, with simple operation, and the calibration efficiency and calibration accuracy are improved.

[0006] Preferably, there is a support platform above the side wall of the mounting seat. The rotary seat is arranged on the support platform and is in clearance fit with the inner wall of the mounting seat. A gland is arranged at the top of the side wall of the mounting seat, and the gland extends to the edge of the rotary seat and is in clearance fit with the rotary seat. The gland of the present invention can limit the rotary seat to ensure the high-precision rotation of the rotary seat and guarantee the horizontal rotation accuracy of the calibration rod.

[0007] Preferably, the first power mechanism includes a first worm and a first worm gear meshing with the first worm. There is a stepped shaft at the center position of the bottom of the rotary seat, and the first worm gear is coaxially installed on the stepped shaft. The first worm is installed on the first support of the adjustable base. During operation, the rotation of the first worm can be used to drive the rotation of the first worm gear, and then drive the rotary seat and the calibration rod to rotate synchronously, with simple operation.

[0008] Preferably, the first monitoring unit includes a first magnetic grating and a first reading head supporting the first magnetic grating. The first magnetic grating is installed at the edge of the bottom surface of the rotary seat for obtaining the position of the first worm gear. The first reading head is installed on the mounting seat close to the first magnetic grating. During the rotation of the rotary seat, the first reading head can read the first magnetic grating at the bottom of the rotary seat to determine the rotation angle of the rotary seat.

[0009] Preferably, the second power mechanism includes a second worm and a second worm gear meshing with the second worm. There are a second support and a third support arranged on the top of the rotary seat. The second worm is rotatably arranged on the second support. The lower part of the calibration rod extends into the upper installation chamber, and a horizontal connecting shaft is fixedly connected to its lower part. The left end of the connecting shaft is inserted into the third support and is in clearance fit with the third support. The second worm gear is coaxially arranged at the right end of the connecting shaft, and a fastening nut is screwed on the right end of the connecting shaft. During operation, since the central axis of the second worm gear is horizontally arranged, it can drive the calibration rod to rotate with the central axis of the connecting shaft as the center, so that the calibration rod can be arbitrarily switched between a horizontal state, a vertical state and an inclined state.

[0010] Preferably, the second monitoring unit includes a second magnetograting and a second reading head that is matched with the second magnetograting. The second magnetograting is installed on the right side of the second worm gear to obtain the position of the second worm gear; the second reading head is installed near the second magnetograting.

[0011] Preferably, both the first and second worm gears have mounting holes at their ends that mate with a manual crank handle. The calibration rod adjustment requires high precision; therefore, a slow adjustment is used, employing a manual crank handle to rotate the first and second worm gears, thereby achieving fine-tuning of the calibration rod.

[0012] Preferably, the upper mounting structure includes a housing disposed on the rotary seat. The housing, base, and mounting seat of the present invention are combined such that both the first and second power mechanisms are located within the mounting cavity, making the present invention aesthetically pleasing, portable, and easy to calibrate.

[0013] The present invention also provides a method for calibrating the accuracy of a CNC machine tool, which employs a CNC machine tool accuracy calibration device, the device comprising a lower mounting structure, a first power mechanism, an upper mounting structure, a second power mechanism, and a calibration rod driven by the second power mechanism; The lower mounting structure includes an adjustable base, a mounting seat disposed on the adjustable base, and a rotary seat disposed on the mounting seat. The first power mechanism is installed in the lower mounting cavity formed by the adjustable base, the mounting seat, and the rotary seat. The first power mechanism is disposed in the lower mounting cavity, and a first monitoring unit for monitoring the position of the rotary seat is disposed in the lower mounting cavity. The upper mounting structure is mounted on the rotary seat. The upper mounting structure has an upper mounting cavity. The second power mechanism is installed in the upper mounting cavity. The bottom of the calibration rod is connected to the second power mechanism. An adjustment hole that mates with the calibration rod is provided on the top plate of the upper mounting structure. A second monitoring unit for monitoring the position of the calibration rod is provided in the upper mounting cavity. The signal output terminals of the first monitoring unit and the second monitoring unit are both connected to the signal input terminal of the controller, and the display signal output terminal of the controller is connected to the signal input terminal of the display screen. The method includes X-axis accuracy correction, Y-axis accuracy correction, and Z-axis accuracy correction. The Y-axis accuracy correction includes the following: The first step is to attach the bases of the two dial indicators to the Z-axis of the CNC machine tool, with the needle of one dial indicator pointing to the positive generatrix of the calibration bar and the needle of the other dial indicator pointing to the side generatrix of the calibration bar. The second step is to adjust the calibration bar to be perpendicular to the worktable and control the CNC machine tool to move the Y-axis up and down. The difference between the highest and lowest points of the Y-axis is the positional deviation of the Y-axis relative to the worktable. The third step is to adjust the leveling pads of the CNC machine tool so that the difference between the highest and lowest points approaches zero.

[0014] Furthermore, the present invention can also calibrate the worktable, and can also perform linkage calibration of any two or three of the X-axis, Z-axis and Y-axis to achieve precision calibration between axes and improve the machining accuracy of the machine tool.

[0015] Compared with existing technologies, the calibration bar of this invention provides a measurement reference for the dial indicator. The first power mechanism drives the calibration bar to rotate horizontally via a rotary seat, thereby adjusting the position of the measurement reference. The second power mechanism drives the calibration bar to swing up and down around its bottom. The first and second monitoring units are used to monitor the rotation angle of the rotary seat and the swing angle of the calibration bar, respectively, to accurately determine the position of the calibration bar and ensure the accuracy of the measurement reference. Using this invention in conjunction with a dial indicator, the accuracy measurement of each axis of a CNC machine tool (single-axis measurement, two-axis linkage measurement, or three-axis linkage measurement) and the worktable can be achieved. The operation is simple, improving calibration efficiency and accuracy. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention.

[0017] Figure 2 yes Figure 1 The magnified view of the calibration rod is omitted.

[0018] Figure 3 yes Figure 2 Top view.

[0019] Figure 4 This is another schematic diagram of the housing described in this invention, where A is a top view and B is a rear view of A.

[0020] Figure 5 This is a schematic diagram of the calibration of the Y-axis of a CNC machine tool.

[0021] Figure 6 This is a schematic diagram of the calibration of the X-axis of a CNC machine tool.

[0022] Figure 7 This is a schematic diagram of the linkage correction between the X and Y axes of a CNC machine tool.

[0023] Figure 8 This is a schematic diagram of the linkage correction between the Y-axis and Z-axis of a CNC machine tool.

[0024] Figure 9 This is a schematic diagram of the linkage correction of the Z-axis, Y-axis and Z-axis of a CNC machine tool. Detailed Implementation

[0025] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. These embodiments are implemented based on the technical solution of the present invention, and detailed implementation methods and specific operation processes are given. However, the scope of protection of the present invention is not limited to the following embodiments.

[0026] It should be noted that, in the description of this invention, relational terms such as “first” and “second” are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0027] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art will understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0028] like Figure 1-4 As shown, the present invention proposes a CNC machine tool accuracy correction device, including a lower mounting structure, a first power mechanism, an upper mounting structure, a second power mechanism, and a calibration rod 1 driven by the second power mechanism; the first power mechanism is disposed in the lower mounting structure and drives the second power mechanism and the calibration rod 1 to rotate circumferentially; the second power mechanism is disposed in the upper mounting structure and can drive the calibration rod 1 to swing relative to each other; the lower mounting structure includes an adjustable base 2a, a mounting seat 2b disposed on the adjustable base 2a, and a rotary seat 2c disposed on the mounting seat 2b; the first power mechanism is installed in the lower mounting cavity surrounded by the adjustable base 2a, the mounting seat 2b, and the rotary seat 2c; a first monitoring unit for monitoring the position of the rotary seat 2c is disposed in the lower mounting cavity; The upper mounting structure is mounted on the rotary seat 2c. It includes a housing 3a fixed to the rotary seat 2c. The housing 3a and the rotary seat 2c form an upper mounting cavity. The second power mechanism is located in the upper mounting cavity. The bottom of the calibration rod 1 extends into the upper mounting cavity and is connected to the second power mechanism. The top plate of the housing 3a has an adjustment hole 3b that mates with the calibration rod. One side wall of the housing 3a has a side through hole that communicates with the adjustment hole. This allows the calibration rod 1 to rotate at any angle (i.e., 0°-90°) in the space between the horizontal and vertical planes under the drive of the second power mechanism to meet the needs of different calibration objects. A second monitoring unit for monitoring the position of the calibration rod 1 is provided in the upper mounting cavity. The signal output terminals of the first and second monitoring units are both connected to the signal input terminal of the controller. The display signal output terminal of the controller is connected to the signal input terminal of the display screen. The first and second monitoring units transmit the detected signals to the controller. After analyzing the signals, the controller displays them on the display screen, which can determine the rotation position of the rotary seat 2c and the rotation position of the calibration rod 1.

[0029] In actual operation, the first power mechanism can drive the rotary seat 2c to rotate, thereby realizing the rotation of the calibration rod 1 on the rotary seat 2c; the second power mechanism can drive the calibration rod 1 to rotate with its bottom as the center; the first monitoring unit is used to monitor the position of the rotary seat 2c, thereby determining the relative rotation position of the calibration rod 1, and the second monitoring unit is used to monitor the rotation angle of the calibration rod 1, further ensuring that the position of the calibration rod 1 can meet the calibration requirements.

[0030] During actual installation, leveling bolts 2f are evenly spaced along the edge of the adjustable base 2a. These bolts are used to adjust the levelness of the adjustable base 2a. A spirit level can be installed at the edge of the adjustable base 2a; during adjustment, the spirit level is observed to determine if the levelness of the adjustable base 2a is properly adjusted.

[0031] In actual manufacturing, the housing 3a and the adjustable base 2a of the present invention can be manufactured as follows: Figure 3 The circular structure shown can also be made using, for example... Figure 4 The square structure shown.

[0032] Combination Figure 2 It is known that a support platform 2d is located above the side wall of the mounting base 2b, and a rotary seat 2c is mounted on the support platform 2d. The rotary seat 2c is clearance-fitted with the inner wall of the mounting base 2b. A pressure cap 2e is provided on the top of the side wall of the mounting base 2b, extending to the edge of the rotary seat 2c. The pressure cap 2e and the rotary seat 2c are clearance-fitted, and the gap between the pressure cap 2e and the rotary seat 2c is controlled within 0.012mm. High-precision assembly can further ensure the high-precision rotation of the rotary seat 2c and further ensure the calibration accuracy. In actual operation, due to the clearance fit between the rotary seat 2c and the mounting base 2b, and the clearance fit between the pressure cap 2e and the rotary seat 2c, the rotary seat 2c can rotate on the mounting base 2b to meet the adjustment requirements of the calibration rod 1 position. The first power mechanism includes a first worm 7a and a first worm wheel 7b meshing with the first worm 7a. A pair of first supports 7c are spaced apart on an adjustable base 2a located below the rotary seat 2c. The two ends of the first worm 7a are respectively mounted on the first supports 7c and are clearance-fitted with them to ensure that the first worm 7a can rotate under force. A stepped shaft (the stepped shaft and the rotary seat 2c can be welded or interference-fitted) is located at the center of the bottom of the rotary seat 2c. The first worm wheel 7b is fixedly connected to the stepped shaft, and a fastening nut is fixedly connected to the bottom of the stepped shaft. When the first worm 7a is under force, it transmits power to the first worm wheel 7b. The first worm wheel 7b drives the rotary seat 2c to rotate synchronously via the stepped shaft, thereby realizing the rotation of the calibration rod 1 to adjust the positions of the side and positive generatrices.

[0033] In actual installation, one end of the first worm 7a has a mounting hole (preferably a square hole), into which the mounting head of the manual crank can be inserted. During operation, the first worm 7a can be rotated by turning the manual crank. To meet the installation requirements of the manual crank, a hole can be made on the side wall of the mounting base 2b so that the manual crank can pass through.

[0034] Combination Figure 2 It is understood that the first monitoring unit includes a first magnetograting 4 and a first reading head that matches the first magnetograting 4. The first magnetograting 4 is installed at the edge of the bottom surface of the rotary seat 2c, and the first reading head is installed on the mounting base 2b near the first magnetograting 4. The distance between the first reading head and the first magnetograting 4 can be as specified in the instruction manual. When the first magnetograting 4 passes the first reading head, a trigger signal is generated. The first magnetograting 4 transmits the signal to the controller and displays the rotation angle of the rotary seat 2c on the display.

[0035] The second power mechanism includes a second worm 5a and a second worm wheel 5b meshing with the second worm 5a. The top of the rotary seat 2c is provided with a second support 5c and a third support 5d. The second supports 5c are a pair and spaced apart. The second worm 5a is mounted on the second support 5c. The second worm 5a and the second support 5c are in clearance fit to ensure that the second worm 5a can rotate relative to the second support 5c under force. The lower part of the calibration rod 1 extends into the upper mounting chamber. A horizontal connecting shaft 5e is fixedly connected to the lower part of the calibration rod 1. The left end of the connecting shaft 5e is inserted into the third support 5d and is in clearance fit with the third support 5d (the clearance is controlled within 0.01mm to ensure high-precision rotation of the connecting shaft). The second worm wheel 5b is coaxially mounted on the right end of the connecting shaft 5e. A fastening nut is screwed onto the right end of the connecting shaft 5e. The second worm wheel 5b is located above the second worm 5a and the two mesh with each other. When the second worm 5a is subjected to force and rotates, it transmits power to the upper second worm wheel 5b. The connecting shaft 5e rotates synchronously with the second worm wheel 5b, causing the calibration rod 1 to rotate around the connecting shaft 5e as the center. The angle between the calibration rod 1 and the horizontal plane can be adjusted to meet the calibration requirements of different calibration objects.

[0036] Combination Figure 2 It is known that the second monitoring unit includes a second magnetograting 6 and a second reading head that matches the second magnetograting 6. The second magnetograting 6 is installed on the right side of the second worm gear 5b, and the second reading head is installed close to the second magnetograting 6. The distance between the second reading head and the second magnetograting 6 is within the range specified in the instruction manual. When the second magnetograting 6 passes the second reading head, a signal is triggered. The second magnetograting 6 transmits the signal to the controller. The controller analyzes the received signal and displays the rotation angle of the calibration rod 1 on the display.

[0037] In actual installation, one end of the second worm 5a has a mounting hole (preferably a square hole), into which the mounting head of the manual crank can be inserted. During operation, the second worm 5a can be rotated by turning the manual crank. To meet the installation requirements of the manual crank, a hole can be made in the side wall of the housing 3a so that the manual crank can pass through.

[0038] When it is necessary to adjust the position of calibration rod 1 relative to the horizontal plane, insert the manual crank handle into the second worm gear 5a and rotate it. The second worm gear 5a is driven by force to rotate the second worm wheel 5b, causing calibration rod 1 to rotate around the connecting shaft 5e. During the rotation, the second magnetograting 6 transmits the position signal to the controller. After analyzing the signal, the controller displays it on the screen, thereby determining the position of calibration rod 1 relative to the horizontal plane. When it is necessary to rotate the calibration rod 1, insert the manual crank into the first worm gear 7a and rotate it. The first worm gear 7a is forced to rotate the first worm wheel 7b, which in turn drives the rotary seat 2c to rotate synchronously, thereby realizing the rotational adjustment of the calibration rod 1. During the rotation, the first magnetograting 4 transmits the position signal to the controller. After analyzing the signal, the controller displays it on the screen to determine the horizontal rotation angle of the calibration rod 1.

[0039] This invention also proposes a method for calibrating the accuracy of CNC machine tools. In this method, the face of the calibration rod 1 opposite to the working axis is considered the front side, and the generatrix at the center of the front side is defined as the positive generatrix. L1 Taking the direction perpendicular to the front as the side, the generatrix at the center of the side is called the lateral generatrix. L2 Specifically, it includes the following: I. Calibration of Single-Axis Accuracy of CNC Machine Tools 1. Y-axis accuracy calibration: Place the CNC machine tool accuracy calibration device of this invention on the machine tool's worktable F. Level the adjusting base 2a using the leveling bolt 2f to ensure the calibration device's horizontality. Mount and fix the dial indicator on the base (using a commercially available magnetic fine-tuning dial indicator). Attach the bases of the two dial indicators to the Z-axis of the CNC machine tool. Adjust the position of each dial indicator by adjusting the bases, so that the needle of one dial indicator hits the positive generatrix of the calibration bar 1, and the needle of the other dial indicator hits the side generatrix of the calibration bar 1. Rotate the second worm gear 5a to rotate the calibration bar 1 around its bottom, adjusting the calibration bar 1 to a vertical position, making it perpendicular to the machine tool's worktable. See details below. Figure 5 The difference between the two extreme positions of the Y-axis of the CNC machine tool within its travel range is the positional deviation of the Y-axis relative to the worktable. After adjusting the leveling pads of the CNC machine tool, the Y-axis is moved up and down repeatedly until the difference between the highest and lowest points approaches zero, thus completing the Y-axis calibration.

[0040] 2. X-axis accuracy calibration: combined with Figure 6 The calibration bar is rotated 90 degrees relative to the Y-axis using the first worm gear and the first worm wheel. Then, the second worm gear 5a is rotated to make the calibration bar 1 rotate with its bottom as the center, adjusting the calibration bar 1 to a horizontal state so that the axis of the calibration bar 1 is parallel to the X-axis. The X-axis of the CNC machine tool is controlled to move within its stroke range. The difference between the dial indicator corresponding to the maximum stroke and the minimum stroke is the position deviation of the X-axis relative to the worktable. The position of the X-axis is fine-tuned. After each fine-tuning, the difference between the maximum stroke and the minimum stroke of the X-axis is measured until the difference approaches zero or equals zero, thus completing the X-axis calibration. Of course, for X-axis that cannot be adjusted, the X-axis guide rail corresponding to the X-axis can be loosened, and the X-axis can be adjusted by fine-tuning the X-axis guide rail.

[0041] 3. Calibration of the Z-axis accuracy: Rotate the second worm 5a to make the calibration rod 1 rotate around its bottom center, adjust the calibration rod 1 to a horizontal state, and make the angle between the axis of the calibration rod 1 and the X-axis 90°; control the Z-axis of the CNC machine tool to move within the stroke range, and the difference between the dial indicators corresponding to the maximum stroke and the minimum stroke is the position deviation of the Z-axis relative to the workbench; finely adjust the position of the Z-axis until this difference approaches zero or equals zero.

[0042] II. Calibration of the workbench of the CNC machine tool (the workbench F is a rotating platform) Adsorb a gauge block on each of the machine tool beds to make the probe heads of the dial indicators on the side axis of the calibration rod 1; rotate the workbench to make the calibration rod 1 contact the dial indicator a, and zero the dial indicator a; rotate the workbench in the opposite direction to make the other dial indicator b contact the calibration rod 1, and zero the dial indicator b; rotate the workbench F, and use the control system of the machine tool to determine the rotation angle of the workbench from the dial indicator a to the dial indicator b; Use the first power mechanism and the second power mechanism to adjust the position of the calibration rod 1, determine the positions corresponding to zeroing of the dial indicator a and the dial indicator b, display the corresponding angle at this time through the display screen, and the angle difference between the angle on the display screen and the rotation angle determined by the control system is the error value of the workbench. This can be eliminated by using the foundation bolts of the CNC machine tool until this angle difference equals zero or approaches zero, and then the calibration of the workbench can be completed.

[0043] III. Linkage calibration between the axes of the CNC machine tool 1. Adjust the calibration rod 1 to make it in the same plane as the axis of the X-axis, and then adjust the calibration rod 1 to make it tilt upward at a certain angle (see Figure 7 ), place the two dial indicators on the positive generatrix and the side generatrix respectively, and then move the Y-axis and the X-axis simultaneously to determine the error of the Y-axis and the error of the X-axis respectively. Finely adjust the corresponding guide rails of the two axes until the error approaches zero or equals zero to complete the calibration of the X-axis and the Y-axis; 2. The above method can be used to complete the linkage calibration between the Y-axis and the Z-axis. For details, see Figure 8 ; 3. Adjust the standard mandrel, rotate it to intersect the projection lines of the Z-axis, Y-axis, and X-axis at a 45° angle, place the two dial indicators on the positive generatrix and the side generatrix respectively, and then move the X-axis, Y-axis, and Z-axis simultaneously to determine the error of the X-axis, the error of the X-axis, and the error of the Z-axis. Eliminate the relative error between the three axes by finely adjusting the positions of the guide rails supporting the X-axis, Y-axis, and Z-axis. For details, see Figure 9 .

[0044] Finally, it should be emphasized that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still make modifications to the technical solutions described in the foregoing embodiments without creative effort, or make equivalent substitutions for some of the technical features. Therefore, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A precision correction device for CNC machine tools, characterized in that: The machine tool is mounted on a worktable and includes a lower mounting structure, a first power mechanism, an upper mounting structure, a second power mechanism, and a calibration bar driven by the second power mechanism. The lower mounting structure includes an adjustable base, a mounting seat disposed on the adjustable base, and a rotary seat disposed on the mounting seat. The first power mechanism is installed in the lower mounting cavity formed by the adjustable base, the mounting seat, and the rotary seat. A first monitoring unit for monitoring the position of the rotary seat is provided in the lower mounting cavity. The upper mounting structure is mounted on the rotary seat. The upper mounting structure includes a housing disposed on the rotary seat, the housing and the rotary seat forming an upper mounting cavity. The second power mechanism is installed in the upper mounting cavity, and the bottom of the calibration rod is connected to the second power mechanism for transmission. An adjustment hole that mates with the calibration rod is provided on the top plate of the housing, and a side through hole communicating with the adjustment hole is provided on one side wall of the housing, so that the second power mechanism drives the calibration rod to swing up and down with its bottom as the center. A second monitoring unit for monitoring the position of the calibration rod is provided in the upper mounting cavity. The signal output terminals of the first monitoring unit and the second monitoring unit are both connected to the signal input terminal of the controller, and the display signal output terminal of the controller is connected to the signal input terminal of the display screen.

2. The CNC machine tool accuracy correction device according to claim 1, characterized in that: The mounting base has a support platform on its side wall, and the rotary seat is disposed on the support platform with a clearance fit between the rotary seat and the inner wall of the mounting base; a pressure cap is provided on the top of the side wall of the mounting base, and the pressure cap extends to the edge of the rotary seat with a clearance fit between the pressure cap and the rotary seat.

3. The CNC machine tool accuracy correction device according to claim 1, characterized in that: The first power mechanism includes a first worm and a first worm wheel meshing with the first worm. The bottom center of the rotary seat has a stepped shaft. The first worm wheel is coaxially mounted on the stepped shaft. The first worm is mounted on a first support provided on the adjustable base.

4. The CNC machine tool accuracy correction device according to claim 3, characterized in that: The first monitoring unit includes a first magnetograting and a first reading head that is matched with the first magnetograting. The first magnetograting is installed at the edge of the bottom surface of the rotary seat to obtain the position of the first worm gear. The first reading head is installed on a mounting base near the first magnetograting.

5. The CNC machine tool accuracy correction device according to claim 3, characterized in that: The second power mechanism includes a second worm and a second worm wheel meshing with the second worm. The top of the rotary seat is provided with a second support and a third support, and the second worm is rotatably mounted on the second support. The lower part of the calibration rod extends into the upper mounting chamber, and a horizontal connecting shaft is fixedly connected to its lower part. The left end of the connecting shaft is inserted into the third support and is clearance-fitted with the third support. The second worm gear is coaxially disposed at the right end of the connecting shaft, and a fastening nut is screwed onto the right end of the connecting shaft.

6. The CNC machine tool accuracy correction device according to claim 5, characterized in that: The second monitoring unit includes a second magnetograting and a second reading head that is matched with the second magnetograting. The second magnetograting is installed on the right side of the second worm gear to obtain the position of the second worm gear; the second reading head is installed near the second magnetograting.

7. The CNC machine tool accuracy correction device according to claim 5, characterized in that: The ends of both the first and second worm gears are provided with mounting holes for engaging with the manual crank handle.

8. A method for calibrating the accuracy of a CNC machine tool, characterized in that: The CNC machine tool accuracy correction device according to any one of claims 1-6 is used. The method includes X-axis accuracy correction, Y-axis accuracy correction, and Z-axis accuracy correction. The Y-axis accuracy correction includes the following: The first step is to attach the bases of the two dial indicators to the Z-axis of the CNC machine tool, with the needle of one dial indicator pointing to the positive generatrix of the calibration bar and the needle of the other dial indicator pointing to the side generatrix of the calibration bar. The second step is to adjust the calibration bar to be perpendicular to the worktable and control the CNC machine tool to move the Y-axis up and down. The difference between the highest and lowest points of the Y-axis is the positional deviation of the Y-axis relative to the worktable. The third step is to adjust the leveling pads of the CNC machine tool so that the difference between the highest and lowest points approaches zero.

9. The CNC machine tool accuracy correction method according to claim 8, characterized in that: It also includes the calibration of the worktable accuracy, and the simultaneous calibration of any two or three of the X-axis, Z-axis and Y-axis.

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