A method for calibrating the spatial position of the milling axis of a machine tool for machining complex and small components based on trial cutting and tool setting

Abstract

The present invention provides a method for calibrating the spatial position of a milling axis of a machine tool for processing complex micro-components based on trial cutting and tool setting, which belongs to the field of complex micro-component processing. The method is to solve the problem that the spatial position of the milling axis of the existing machine tool cannot be accurately and efficiently calibrated due to the offset placement. Based on trial cutting and tool setting, the present invention sets the position of the turntable when the axis of the milling axis is parallel to the moving direction of the Z axis as the zero point, and conducts trial cutting and tool setting on the tool and the workpiece when the turntable is at the zero point position, clockwise deflection, and counterclockwise deflection. The three-dimensional coordinates of the tool tip position in the three positions are recorded, and the relative position coordinates of the tool tip point in the machine tool space are obtained by combining the spatial coordinates of the machine tool coordinate system. The same circle where the tool tip point is located when the three tool setting is completed is numerically fitted through theoretical analysis, and the spatial position of the milling axis is solved by the above-mentioned specific deflection angle, thereby realizing spatial position calibration, and providing data support and precision guarantee for the writing of micro-structure processing programs and processing surface quality.

Description

Technical Field

[0001] The present invention relates to the technical field of complex micro-component processing, and in particular to a method for calibrating the spatial position of a milling axis of a machine tool for processing complex micro-components based on trial cutting and tool setting. Background Art

[0002] With the rapid development of modern science and technology, various complex, small, integrated, thin-walled spherical shell components with high precision and surface quality have found widespread application in defense, military, aerospace, and electronic information technology fields. These components, with diameters ranging from 1-5 mm and shell thicknesses ranging from 20-120 μm, require dozens to hundreds of characteristic micro-pit structures with lateral dimensions of 50-200 μm and longitudinal dimensions of 0.5-20 μm to be machined onto their surfaces. These surfaces must also achieve submicron shape accuracy, nanometer-level surface roughness, and micron-level pit spacing errors. These precision and surface quality requirements require specialized ultra-precision machining processes based on the structural characteristics and using dedicated ultra-precision machine tools.

[0003] The high-precision machining requirements for complex, microscopic components like thin-walled spherical shells, constrained by microscopic spatial scales, necessitate the construction of a dedicated ultra-precision five-axis machine tool to achieve stable and controllable removal of microstructures. However, the assembly accuracy of the moving components and the spatial positional errors between them directly impact the workpiece quality. Due to process requirements, the machine's milling spindle is offset from the rotary table, with the tool secured to the tool holder by a high-precision chuck. Accurately determining the distance between the milling spindle axis and the rotary table's rotation center, as well as the angle between the line connecting the tool tip and the rotary table's rotation center and the milling spindle axis, is crucial for programming microstructures and ensuring surface quality. Existing processes primarily rely on placing or clamping standard rods on the rotary table and the milling spindle's clamping end to locate their respective coaxial axes. A wide-field-of-view CCD camera then captures the standard rod's spatial position to determine the spatial coordinates. This cumbersome and inefficient process places high demands on both the standard rod and the CCD camera. Therefore, there is an urgent need to design an efficient, high-precision and convenient milling axis spatial position calibration method to reduce assembly errors, achieve high-precision processing of microstructures, and fill the technological gap. Summary of the Invention

[0004] The technical problems to be solved by the present invention are:

[0005] In order to solve the problem that the spatial position of the existing machine tool milling axis cannot be efficiently calibrated due to the offset placement.

[0006] The present invention is to solve the above technical problems using the following technical solutions:

[0007] The present invention provides a method for calibrating the spatial position of a milling axis of a machine tool for processing complex micro components based on trial cutting and tool setting, comprising the following steps:

[0008] S100, aligning the zero position deflection of the rotary table. After enabling the zero return coarse adjustment through the ultra-precision five-axis linkage machine tool, the rotary table zero position fine adjustment is performed using an inductive micrometer to align the deflection angle of the milling axis relative to the Z-axis moving direction.

[0009] S200, trial cutting and tool setting adjustment: at the zero point position of the turntable, move the turntable along the X-axis, Y-axis and Z-axis directions, observe the relative position of the tool and the workpiece through the horizontal CCD camera and the vertical CCD camera, complete the zero point trial cutting and tool setting, and record the coordinates of the tool tip point at this time; return the turntable to a safe position, rotate it clockwise and counterclockwise by angles α1 and α2 respectively, and move the turntable again along the X-axis, Y-axis and Z-axis directions to perform the second and third tool setting operations, and record the corresponding tool tip point position coordinates;

[0010] S300, spatial position calibration, the tool tip point position coordinates after three tool settings obtained in step S200 are used to calibrate the milling axis spatial position, fit the common circle of the three points, and solve to obtain the spatial coordinates of the turntable rotation center, the distance of the milling axis axis relative to the turntable rotation center, and the angle between the line connecting the tool tip point and the turntable rotation center and the milling axis axis, thus completing the milling axis spatial position calibration.

[0011] Furthermore, in step S100, it specifically includes:

[0012] S110, open the control software of the complex micro-component ultra-precision shape-controlled machining system, establish communication between the host computer and the controller, enable each axis with one button, and perform zero return operations on the X-axis, Y-axis, Z-axis, workpiece C-axis, and turntable in sequence to establish a zero position reference for each axis;

[0013] S120, coarse adjustment of the zero position alignment of the turntable. The program is run to control the turntable to perform a clockwise jog rotation operation in a coordinated manner with decreasing jog steps. When the milling axis and the Z-axis movement direction are nearly parallel, the jog step is reduced to 1 / 5-1 / 10 of the origin step, thereby achieving coarse adjustment of the zero position alignment of the turntable.

[0014] S130: Perform fine adjustment on the zero position of the rotary table. Fix one end of the inductive micrometer to the bed of the ultra-precision five-axis linkage machine tool. Adjust the probe to align with the reference surface of the milling axis side wall and make contact. Control the Z-axis inching and fixed-length motion by running the program. Record the change in the inductive micrometer reading within the full stroke. Rotate the rotary table by a small angle and record the rotation angle.

[0015] S140, repeatedly execute step S130 to the full stroke movement process of the Z axis until the reading of the inductive micrometer changes within the threshold range, completing the zero position deflection alignment of the turntable, and the accumulated rotation angle is θ, which is the zero position deflection angle.

[0016] Furthermore, in step S200, it specifically includes:

[0017] S210, when the turntable is at zero point, move the turntable along the X-axis, Y-axis, and Z-axis directions, observe the contact area between the tool and the workpiece using the horizontal CCD camera and the vertical CCD camera to perform zero-point tool setting, and obtain the position O1 (x1, y1, z1) of the tool tip after tool setting.

[0018] S220, move the turntable along the Z axis in the negative direction by a safe distance Z s1 , then rotate the turntable clockwise by α1, move the turntable along the X-axis, Y-axis, and Z-axis directions, and monitor the contact area between the tool and the workpiece through the horizontal CCD camera and the vertical CCD camera to achieve the second precise tool setting, and obtain the position O2 (x2, y2, z2) of the tool tip point after the tool setting is completed;

[0019] S230, move the turntable again along the negative direction of the Z axis by a safe distance Z s2 , then adjust the turntable counterclockwise by angle α1 to the zero position, rotate counterclockwise by angle α2, move the turntable along the X-axis, Y-axis, and Z-axis directions, and monitor the contact area between the tool and the workpiece through the horizontal CCD camera and the vertical CCD camera to achieve the third precise tool setting and obtain the position O3 (x3, y3, z3) of the tool tip after the tool setting is completed.

[0020] Furthermore, in step S300, it specifically includes:

[0021] S310, taking the rotation center of the turntable (7) as a reference, and obtaining the distribution diagram of the three tool setting completion points relative to the rotation center of the turntable (7) from the tool tip position coordinates when the three tool setting are completed,

[0022] S320. Based on the position calibration algorithm, when the rotary table (7) is at the zero position and is deflected clockwise by α1, the distance O2A between the tool tips along the X-axis direction is (x2-x1), and the distance O1O2 between the two tool tips is:

[0023] (1)

[0024] Wherein, η represents the angle between the line connecting the tool tip and the rotation center of the rotary table (7) and the axis of the milling axis (1) when the rotary table (7) is at the zero point tool setting;

[0025] The length of the line connecting the tool tip and the rotation center of the rotary table (7) is:

[0026] (2)

[0027] Wherein, O1C represents the line between the tool tip and the axis of the turntable (7) when the turntable (7) is at the zero position; O2C represents the line between the tool tip and the axis of the turntable (7) when the turntable (7) rotates clockwise by α1;

[0028] When the rotary table (7) is at the zero position and deflected counterclockwise by α2, the distance O1B between the tool tips along the X-axis direction is (x1-x3), and the distance O1O3 between the tool tips is:

[0029] (3)

[0030] in, It represents the angle between the line connecting the two tool tip points O1O3 and the negative direction of the X axis when the rotary table (7) is at the zero point and deflected α2 counterclockwise;

[0031] At this time, the length of the line connecting the tool tip and the rotation center of the rotary table (7) is:

[0032] (4)

[0033] Wherein, O3C represents the line connecting the tool tip and the axis of the rotary table (7) when the rotary table (7) rotates α2 counterclockwise for tool setting;

[0034] From formula (1) and formula (2), we can get:

[0035] (5)

[0036] From formula (3) and formula (4), we can get:

[0037] (6)

[0038] When the rotary table (7) is at the zero point, the angle β between the line connecting the tool tip and the rotary table (7) rotation center and the milling axis (1) is:

[0039] (7)

[0040] When the rotary table (7) is at the zero position for tool setting, the distance CP between the rotary center and the axis of the milling axis (1) is:

[0041] (8)

[0042] According to the distribution diagram of S310:

[0043] (9)

[0044] S330, calibrate the spatial position of the milling axis (1) based on the functional relationship between the tool tip points in the three positions of the rotary table (7), and obtain the following two expressions of the same line segment O1C in the triangle O1O2C and the triangle O1O3C using formulas (5) and (6) in step S320:

[0045] (10)

[0046] Combining formula (9) and formula (10), we get:

[0047] (11)

[0048] (12)

[0049] S340, η obtained in step S330 and , substitute into formula (5) to obtain the distance O1C between the tool tip and the rotary table rotation center when the rotary table is at the zero point position; substitute into formula (7) to obtain the angle β between the line connecting the tool tip and the rotation center and the milling axis when the rotary table is at the zero point position; substitute into formula (8) to obtain the distance CP between the rotary table rotation center and the milling axis, and complete the spatial position calibration of the milling axis.

[0050] Furthermore, in step S120, the initial jog step length is 10°, and when the milling spindle axis is nearly parallel to the Z-axis movement direction, the jog step length is reduced to 2°.

[0051] Furthermore, in step S130, the movement stroke is -50mm~50mm. When the Z axis moves from -50mm to 50mm, if the reading of the inductive micrometer becomes larger, the turntable is rotated clockwise by a small angle and the rotation angle is recorded; if the reading of the inductive micrometer becomes smaller, the turntable is rotated counterclockwise by a small angle; after the rotation is completed, the full-stroke movement operation of the Z axis is continued to be executed, and the changes in the reading of the inductive micrometer are observed.

[0052] Furthermore, in steps S210-S230, the tool setting process includes adjusting the relative positions of the tool and the workpiece in the YZ vertical plane under the horizontal CCD camera, adjusting the tool and the workpiece to the same height, and then adjusting the relative positions in the XZ horizontal plane until the tool and the workpiece are located on the same axis.

[0053] Furthermore, during the three tool setting processes, the tool and the workpiece are at the same height in the Y-axis direction.

[0054] Compared with the prior art, the present invention has the following beneficial effects:

[0055] This invention addresses the problem of inefficient spatial position calibration due to offset placement of the milling axis of a five-axis linkage machine tool used for high-precision machining of micro-pit structures on the surfaces of complex, tiny components such as thin-walled spherical shells. Based on trial cutting and tool setting, the coordinates of the tool tip in three different positions of the turntable are used to achieve spatial alignment using a position calibration algorithm. This provides parameter support for machining program writing and meets the high-precision machining requirements of submicron shape accuracy, nanometer-level surface roughness, and micron-level pit spacing errors on the surface of microsphere targets. Experimental verification shows that the surface roughness of the machined microstructure can reach 27nm after calibration, an improvement of 56.27% compared to the original accuracy.

[0056] A high-resolution CCD camera is used to observe the contact between the workpiece and the tool setting area. Combined with a high-precision linear motion unit for tool setting adjustment, the center of the ball end milling cutter can be accurately aligned with the C-axis spatial rotation axis to achieve precise tool setting.

[0057] This method uses a high-precision inductive micrometer to align the zero-position angle of the rotary table with high precision and efficiency, providing an important zero-position reference for subsequent tool trial cutting.

[0058] This method has a certain universality. It is not only suitable for the spatial position calibration of the milling axis of machine tools used for processing micro-pit structures on the surfaces of complex and tiny components, but can also be further promoted for the spatial position alignment of the offset spindle of conventional multi-axis machine tools, thereby ensuring the processing accuracy of the machine tools. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 A three-dimensional diagram of the layout of a special machine tool for processing the surface microstructure of a complex micro-component according to an embodiment of the present invention;

[0060] Figure 2 A top view of the layout of a special machine tool for processing surface microstructures of complex micro components after zero-angle alignment in an embodiment of the present invention;

[0061] Figure 3 Schematic diagram of the relative positions of various machine tool components after the turntable returns to zero in the zero position state in an embodiment of the present invention;

[0062] Figure 4 Schematic diagram of the turntable after clockwise rotation α1 in an embodiment of the present invention;

[0063] Figure 5 Schematic diagram of the turntable after counterclockwise rotation α2 in an embodiment of the present invention;

[0064] Figure 6 Schematic diagram of the distribution of the three tool setting completion points relative to the rotation center of the turntable in an embodiment of the present invention;

[0065] Figure 7 This is a simplified diagram of the distribution of the three tool setting completion points relative to the rotation center of the turntable in an embodiment of the present invention.

[0066] Description of reference numerals:

[0067] 1. Milling axis; 2. Tool; 3. Horizontal CCD camera; 4. Vertical CCD camera; 5. Workpiece axis; 6. Workpiece; 7. Rotary table. DETAILED DESCRIPTION

[0068] In the description of the present invention, it should be noted that the terminology in each embodiment, such as "up", "down", "front", "back", "left", "right", etc., which indicate directions, are only for simplifying the description of the positional relationship based on the drawings in the specification, and do not mean that the referred elements and devices must be operated in accordance with the specific directions and defined operations and methods and structures in the specification. Such directional nouns do not constitute a limitation to the present invention.

[0069] In the description of the present invention, it should be noted that the terms "first," "second," and "third" mentioned in the embodiments of the present invention are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly specifying the number of the technical features indicated. Therefore, a feature specified as "first," "second," or "third" may explicitly or implicitly include one or more of such features.

[0070] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0071] Combine Figure 1 As shown, on the ultra-precision five-axis linkage machine tool, the directions of the X-axis, Y-axis and Z-axis are as shown in the figure, the turntable 7 is fixed on the horizontal Z-axis guide rail, and can move along the Z-axis direction with the Z-axis guide rail; the milling axis 1 is offset and placed on the turntable 7; the tool 2 is set at the tool clamping end of the milling axis 1; the workpiece axis 5 is fixed on the vertical Y-axis slide and moves along the Y-axis direction with the Y-axis slide; the Y-axis slide is fixed on the horizontal X-axis guide rail, and the Y-axis slide can move along the X-axis direction with the X-axis guide rail; a 26-megapixel high-resolution horizontal CCD camera (referred to as horizontal CCD camera 3) is fixed on the turntable 7; the tip of the tool 2 is located on the axis of the horizontal CCD camera 3, and the axis of the horizontal CCD camera 3 is perpendicular to the axis of the milling axis 1, which is used to realize the observation of the tip area of ​​the tool 2; the 26-megapixel high-resolution vertical CCD camera (referred to as vertical CCD camera 4) is fixed on the Y-axis slide for observing the tip area of ​​the workpiece 6.

[0072] Specific implementation plan 1: Combined Figures 1 to 7 As shown, the present invention provides a method for calibrating the spatial position of a milling axis of a machine tool for processing complex micro components based on trial cutting and tool setting, comprising the following steps:

[0073] S100, align the zero angle of the rotary table 7, after the ultra-precision five-axis linkage machine tool is enabled to return to zero, align the deflection of the milling axis 1 relative to the moving direction of the Z axis; combined with Figure 3 As shown in the figure, the zero return operation is enabled by the running program of the ultra-precision five-axis linkage machine tool. When the turntable 7 returns to the zero position, there is an angle θ between the axis of the milling axis 1 and the moving direction of the Z axis. The turntable 7 is controlled by the running program to rotate to the appropriate angle, and then the high-precision and high-resolution inductive micrometer is used to measure the table to complete the zero angle alignment, and this position is set as the zero point position of the turntable 7, as shown in the figure. Figure 2 As shown;

[0074] Specifically include:

[0075] S110, open the control software of the complex micro-component ultra-precision shape-controlled machining system, establish communication between the host computer and the controller, enable each axis with one button, and perform zero return operations on the X-axis, Y-axis, Z-axis, workpiece C-axis, and turntable 7 in sequence to establish a zero position reference for each axis;

[0076] S120, coarse adjustment of zero position alignment of turntable 7: by running the program to control the turntable to perform clockwise jogging operation with a 10° jogging step length, observe the parallelism between the axis of milling axis 1 and the moving direction of Z axis. When they are close to parallel, reduce the jogging step length to 2° to achieve coarse adjustment of zero position alignment of turntable 7;

[0077] S130: Perform fine adjustment on the zero position of rotary table 7. Fix one end of an inductive micrometer (0.1μm accuracy) to the bed of the ultra-precision five-axis linkage machine tool. Adjust the probe to align with the reference surface on the side wall of milling axis 1 and make contact. Control the Z-axis inching fixed-length motion through the program, with a motion range of -50mm to 50mm. Record the changes in the inductive micrometer reading within the full range. Rotate rotary table 7 by a small angle and record the rotation angle.

[0078] When the Z axis moves from -50mm to 50mm, if the reading on the inductive micrometer increases, rotate the turntable 7 clockwise by a small angle and record the rotation angle; if the reading on the inductive micrometer decreases, rotate the turntable 7 counterclockwise by a small angle; after the rotation is completed, continue to perform the full-stroke movement operation of the Z axis and observe the changes in the reading on the inductive micrometer;

[0079] S140, repeatedly perform step S130 to the full stroke movement process of the Z axis until the reading of the inductive micrometer changes within 0.2 μm, that is, the zero position deflection angle alignment of the turntable 7 is completed, and the accumulated rotation angle is θ, which is the zero position deflection angle;

[0080] After the turntable 7 returns to zero position, its spatial layout is as follows Figure 3 As shown;

[0081] S200, trial cutting and tool setting adjustment: at the zero point position of the turntable 7, move the turntable 7 along the X-axis, Y-axis and Z-axis directions, observe the relative position of the tool 2 and the workpiece 6 through the horizontal CCD camera 3 and the vertical CCD camera 4, complete the zero point trial cutting and tool setting, and record the tool tip position coordinates after the tool setting is completed; return the turntable 7 to the safe position, rotate α1 and α2 in the clockwise and counterclockwise directions respectively, and move the turntable 7 in the X-axis, Y-axis and Z-axis directions again to perform the second and third tool setting operations, and record the corresponding tool tip position coordinates;

[0082] Specifically include:

[0083] S210, when the turntable 7 is at the zero point, the turntable 7 is moved along the X-axis, Y-axis, and Z-axis directions, and the contact area between the tool 2 and the workpiece 6 is observed by the horizontal CCD camera 3 and the vertical CCD camera 4 to perform zero-point tool setting, and the position O1 (x1, y1, z1) of the tool tip after the tool setting is completed is obtained;

[0084] When each linear motion unit is moved and adjusted, the relative position of tool 2 and workpiece 6 in the YZ vertical plane is adjusted under the horizontal CCD camera 3. First, the workpiece 6 and tool 2 are adjusted to the same height. Then, the relative position in the XZ horizontal plane is adjusted until the workpiece 6 and tool 2 are on the same axis. The Z axis is micro-fed to achieve zero-point precision tool setting. The position of the tool tip O1 (x1, y1, z1) at this time is recorded in the control system.

[0085] The horizontal CCD camera 3 and the vertical CCD camera 4 are used to observe whether there is any trace of chips generated in the contact area to determine whether the tool setting is completed;

[0086] S220, combined Figure 4 As shown, the turntable 7 is moved along the negative direction of the Z axis by a safe distance Z s1 , then rotate the turntable 7 clockwise by α1 and move it along the X-axis, Y-axis, and Z-axis directions. The contact area between the tool 2 and the workpiece 6 is monitored by the horizontal CCD camera 3 and the vertical CCD camera 4 to achieve a second precise tool setting. The position O2 (x2, y2, z2) of the tool tip after the tool setting is completed is obtained.

[0087] S230, combined Figure 5 As shown, the turntable 7 is moved again along the negative direction of the Z axis by a safety distance Z s2 Then, the turntable 7 is swung counterclockwise by an angle α1 to the zero position, and then rotated counterclockwise by an angle α2. The turntable 7 is moved along the X-axis, Y-axis, and Z-axis directions. The contact area between the tool 2 and the workpiece 6 is monitored by the horizontal CCD camera 3 and the vertical CCD camera 4 to achieve the third precise tool setting. The position O3 (x3, y3, z3) of the tool tip after the tool setting is completed is obtained.

[0088] S300, spatial position calibration, using the tool tip position coordinates after three tool settings obtained in step S200, perform spatial position calibration of the milling axis 1, fit the common circle of the three points, and solve to obtain the spatial coordinates of the rotation center of the turntable 7, the distance of the axis of the milling axis 1 relative to the rotation center of the turntable 7, and the angle between the line connecting the tool tip of the tool 2 and the rotation center of the turntable 7 and the axis of the milling axis 1, thus completing the spatial position calibration of the milling axis 1;

[0089] Specifically include:

[0090] S310, combined Figure 6 As shown, with the rotation center of the turntable 7 as the reference, the coordinates of the tool tip point when the three tool setting are completed are used to obtain the distribution diagram of the three tool setting completion points relative to the rotation center of the turntable 7. Figure 6 It can be seen that

[0091] When the turntable 7 rotates clockwise by α1 with the zero position as the axis, the angle of rotation of the line connecting the tool tip and the rotation center is also α1; when the turntable 7 rotates counterclockwise by α2 with the zero position as the axis, the angle of rotation of the line connecting the tool tip and the rotation center is also α2. When the turntable 7 is in three different tool setting positions, the same horizontal CCD camera 3 monitors the relative position of the tool 2 and the workpiece 6 in the YZ plane, ensuring that the height of the workpiece 6 and the tool 2 in the Y-axis direction is consistent, that is, y1 = y2 = y3;

[0092] When the rotary table 7 is at the zero point tool setting, the angle between the line connecting the tool tip and the rotation center of the rotary table 7 and the axis of the milling axis 1 is β;

[0093] When the rotary table 7 is at zero point tool setting and clockwise deflected by α1, the angle between the line connecting the two tool tip points O1O2 and the negative direction of the Z axis is η;

[0094] When the rotary table 7 is at zero point and deflected counterclockwise by α2, the angle between the line connecting the two tool tip points O1O3 and the negative direction of the X axis is ;

[0095] O1C represents the line between the tool tip and the axis of the turntable 7 when the turntable 7 is at the zero position; O2C represents the line between the tool tip and the axis of the turntable 7 when the turntable 7 rotates clockwise by α1; O3C represents the line between the tool tip and the axis of the turntable 7 when the turntable 7 rotates counterclockwise by α2;

[0096] S320, based on the position calibration algorithm, extract the three tool setting completion points relative to the center of the turntable 7. When the turntable 7 is at the zero point tool setting, the clockwise deflection angle α1 tool setting, and the counterclockwise deflection angle α2 tool setting, the distribution of the line connecting the tool tip point and the rotation center of the turntable 7 is as follows: Figure 7As shown in the figure, when the turntable 7 is at the zero position and deflected α1 clockwise for tool setting, the distance O2A between the tool tips along the X-axis direction is (x2-x1), and the distance O1O2 between the tool tips is:

[0097] (1)

[0098] The length of the line connecting the tool tip and the rotation center of the rotary table 7 is:

[0099] (2)

[0100] When the turntable 7 is at the zero position and deflected counterclockwise by α2, the distance O1B between the tool tips along the X-axis direction is (x1-x3), and the distance O1O3 between the tool tips is:

[0101] (3)

[0102] At this time, the length of the line connecting the tool tip and the rotation center of the rotary table 7 is:

[0103] (4)

[0104] From formula (1) and formula (2), we can get:

[0105] (5)

[0106] From formula (3) and formula (4), we can get:

[0107] (6)

[0108] The angle β is:

[0109] (7)

[0110] When the rotary table 7 is at the zero position for tool setting, the distance CP between the rotation center and the axis of the milling axis 1 is:

[0111] (8)

[0112] Depend on Figure 7 The angle relationship can be obtained:

[0113] (9)

[0114] The line segment CM represents the perpendicular line of the line connecting the tool tip points relative to the rotation center of the turntable 7 when the turntable 7 is at the zero position and the tool is set with a clockwise deflection of α1, and the foot of the perpendicular is M;

[0115] Line segment CN represents the perpendicular line of the line connecting the tool tip points relative to the rotation center of the turntable 7 when the turntable 7 is at zero position and deflected α2 counterclockwise, with the foot of the perpendicular being N.

[0116] S330, further calibrate the spatial position of the milling axis 1 based on the functional relationship between the tool tip points under the three positions of the rotary table 7. From formula (5) and formula (6) in step S320, the two expressions of the same line segment O1C in the triangle O1O2C and the triangle O1O3C can be obtained:

[0117] (10)

[0118] Combining formula (9) and formula (10), we can get:

[0119] (11)

[0120] (12)

[0121] S340, η obtained in step S330 and , substitute into formula (5) to obtain the distance O1C between the tool tip and the rotation center of the turntable 7 when the tool is set at the zero point of the turntable 7; substitute into formula (7) to obtain the angle β between the line connecting the tool tip and the rotation center and the axis of the milling axis 1 when the tool is set at the zero point of the turntable 7; substitute into formula (8) to obtain the distance CP between the rotation center of the turntable 7 and the axis of the milling axis 1, that is, the distance between the milling spindle axis and the rotation center of the turntable 7, and the angle between the line connecting the tool tip of the tool 2 and the rotation center of the turntable 7 and the axis of the milling axis 1 are accurately obtained, and the spatial position calibration of the milling axis 1 is completed.

[0122] Preferably, in step S110, the control software for the shape-controlling machining system is independently developed in the .NET framework based on the C# language. It has object-oriented rapid response capabilities and can realize intelligent control of multi-axis machine tool processing processes. The control software for the shape-controlling machining system has applied for software copyright, and the software is the control software for ultra-precision shape-controlling machining of complex micro-components [abbreviated as: iCMP], registration number: 2024SR0139826 (certificate issued). The controller is a Umac high-precision multi-axis intelligent controller with hardware 64-bit double-precision floating-point calculations, supports 1-2GB, can execute script language controller programs, supports G-code motion programs, and asynchronous "PLC" programs. The X-axis guide rail, Y-axis carriage, and Z-axis guide rail all use liquid hydrostatic guide rails, driven by linear motors, and use grating scale feedback to achieve closed-loop control, with positioning accuracy better than 0.4μm full stroke. The C-axis uses gas hydrostatic bearings and is driven by a rotary motor, with rotation accuracy better than 50nm. The turntable 7 adopts liquid hydrostatic bearings and is driven by a rotary motor, with a positioning accuracy better than 0.4".

[0123] Preferably, in step S120, the milling spindle 1 adopts a gas hydrostatic bearing and is driven by a rotary motor with a rotation accuracy better than 30 nm.

[0124] Preferably, in step S130, the inductive micrometer is of model Millimar 1240, with an accuracy of 0.1 μm and a resolution of 0.01 μm.

[0125] Preferably, in step S210, the tool 2 is a single-edged ball-end diamond milling cutter, which facilitates efficient material removal and high-precision tool setting. The horizontal CCD camera 3 and the vertical CCD camera 4 are both 26-megapixel high-resolution industrial cameras with a minimum image pixel resolution of 1.25 μm.

[0126] Example

[0127] A method for calibrating the spatial position of a milling axis of a special machine tool for machining complex and small components based on trial cutting and tool setting includes the following steps:

[0128] S100. After ensuring that the hardware connection of the precision five-axis linkage machine tool is correct, the machine tool is powered on to establish communication, each axis is enabled and returned to zero, and the zero position deflection angle of milling axis 1 is aligned using an inductive micrometer. After coarse and fine adjustments, the zero position deflection angle of milling axis 1 is obtained as θ = 45.737°, and this position is set as the zero point;

[0129] S200, move the turntable 7 along the X-axis, Y-axis, and Z-axis directions, and observe the contact area between the workpiece 6 and the tool 2 through the horizontal CCD camera 3 and the vertical CCD camera 4, perform tool setting between the workpiece 6 and the tool 2 at the zero position, and record the tool tip position coordinates O1(x1, y1, z1)=(-84.393, 27.334, 10.573) mm when the tool setting is completed;

[0130] S300, move the safety distance Z along the negative direction of the Z axis s1 =20mm, deflect the turntable 7 clockwise by α1=30° around the center of rotation, and then move the turntable 7 along the X-axis, Y-axis, and Z-axis directions. Use the horizontal CCD camera 3 and the vertical CCD camera 4 to observe the contact area between the workpiece 6 and the tool 2. Perform a second precise tool setting at this position and record the tool tip position coordinates O2(x2, y2, z2)=(6.079, 27.334, 10.582) mm when the tool setting is completed.

[0131] S400, move the safety distance Z along the negative direction of the Z axis s2= 20 mm, rotate the turntable 7 counterclockwise by an angle of α1 = 30° to straighten it, and then rotate it counterclockwise by α2 = 20°. Then move the turntable 7 along the X-axis, Y-axis, and Z-axis directions, and use the horizontal CCD camera 3 and the vertical CCD camera 4 to observe the contact area between the workpiece 6 and the tool 2. Perform the third precise tool setting at this position, and record the tool tip position coordinates O3 = (x3, y3, z3) = (-139.385, 27.334, 36.200) mm when the tool setting is completed. Move the turntable 7 along the negative Z-axis by a safety distance of 20 mm.

[0132] S500, we get O2A=x2-x1=90.472 mm, O1B=x1-x3=54.992 mm, α1=30°, α2=20°, and then put them into formula (7) and formula (8), we get:

[0133] (13)

[0134] (14)

[0135] Depend on , η, and put them into formula (5), we get:

[0136] O1C=174.780 mm (15)

[0137] Substituting into formula (7), we get:

[0138] β=15.047° (16)

[0139] Substituting into formula (8), we get:

[0140] CP = 45.374 mm (17)

[0141] The above analysis and calculation show that the rotation distance between the milling axis axis and turntable 7 of the five-axis linkage machine tool dedicated to high-precision machining of micro-pit structures on the surfaces of complex micro-components such as thin-walled spherical shells is 45.374 mm, and the angle between the line connecting the tool tip of tool 2 and the rotation center of turntable 7 and the axis of milling axis 1 is 15.047°. The spatial position calibration of milling axis 1 is completed. After calibration, the surface roughness of the machined microstructure reaches 27 nm, which is 56.27% higher than the original accuracy. This provides machine tool parameter support for the writing of microstructure machining programs and provides an important guarantee for the quality of the machined surface.

[0142] Although the present invention is disclosed as above, the scope of protection disclosed by the present invention is not limited thereto. Those skilled in the art of the present invention may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method for calibrating the spatial position of the milling axis of a machine tool for processing complex and small components based on trial cutting and tool setting, characterized in that: The following steps are involved: S100, the zero position deflection of the rotary table (7) is aligned. After the ultra-precision five-axis linkage machine tool is enabled to return to zero for rough adjustment, the rotary table (7) is finely adjusted for zero position alignment using an inductive micrometer to align the deflection angle of the milling axis (1) relative to the Z-axis moving direction; Specifically include: S110, open the control software of the ultra-precision shape-controlled machining system for complex micro-components, establish communication between the host computer and the controller, enable each axis with one key, and perform zero return operations on the X-axis, Y-axis, Z-axis, workpiece C-axis, and turntable (7) in sequence to establish the zero position reference of each axis; S120, coarse adjustment of zero position alignment of the rotary table (7), by running the program to control the rotary table (7) to perform clockwise jogging rotation operation in a manner of coordinated decreasing jogging step length, and when it is observed that the axis of the milling axis (1) is close to parallel with the moving direction of the Z axis, the jogging step length is reduced to 1 / 5-1 / 10 of the original jogging step length, thereby achieving coarse adjustment of zero position alignment of the rotary table (7); S130, the rotary table (7) is finely adjusted for zero position alignment, one end of the inductive micrometer is fixed on the bed of the ultra-precision five-axis linkage machine tool, the probe is adjusted to align with the reference surface of the side wall of the milling axis (1) and touch it, the Z axis is controlled by running the program, the change of the inductive micrometer reading within the full stroke is recorded, the rotary table (7) is rotated at a small angle and the rotation angle is recorded; S140, repeatedly perform step S130 to the full stroke movement process of the Z axis until the reading of the inductive micrometer changes within the threshold range, completing the zero position deflection alignment of the turntable (7), and the accumulated rotation angle is θ, which is the zero position deflection angle; S200, trial cutting and tool setting adjustment, at the zero point position of the turntable (7), move the turntable (7) along the X-axis, Y-axis and Z-axis directions, observe the relative position of the tool (2) and the workpiece (6) through the horizontal CCD camera (3) and the vertical CCD camera (4), complete the zero point trial cutting and tool setting, and record the tool tip position coordinates at this time; return the turntable (7) to the safe position, rotate it in the clockwise and counterclockwise directions by angles α1 and α2 respectively, and move the turntable (7) again along the X-axis, Y-axis and Z-axis directions to perform the second and third tool setting operations, and record the corresponding tool tip position coordinates; Specifically include: S210, when the turntable (7) is at the zero point, the turntable (7) is moved along the X-axis, Y-axis and Z-axis directions, and the contact area between the tool (2) and the workpiece (6) is observed by the horizontal CCD camera (3) and the vertical CCD camera (4), so as to achieve zero-point tool setting and obtain the position O1 (x1, y1, z1) of the tool tip after the tool setting is completed; S220, move the turntable (7) along the Z axis in the negative direction by a safe distance Z s1 , then rotate the turntable (7) clockwise by α1, move the turntable (7) along the X-axis, Y-axis and Z-axis directions, monitor the contact area between the tool (2) and the workpiece (6) through the horizontal CCD camera (3) and the vertical CCD camera (4), and achieve a second precise tool setting, and obtain the position O2 (x2, y2, z2) of the tool tip point after the tool setting is completed; S230, move the turntable (7) again along the negative direction of the Z axis by a safe distance Z s2 , then the turntable (7) is swung counterclockwise by an angle α1 to the zero position, and then rotated counterclockwise by an angle α2, and the turntable (7) is moved along the X-axis, Y-axis, and Z-axis directions, and the contact area between the tool (2) and the workpiece (6) is monitored by the horizontal CCD camera (3) and the vertical CCD camera (4), so as to achieve the third precise tool setting and obtain the position O3 (x3, y3, z3) of the tool tip point after the tool setting is completed; S300, spatial position calibration, through the tool tip point position coordinates after three tool settings obtained in step S200, the spatial position calibration of the milling axis (1) is performed, the common circle of the three points is fitted, and the spatial coordinates of the rotation center of the turntable (7), the distance of the axis of the milling axis (1) relative to the rotation center of the turntable (7) and the angle between the line connecting the tool tip point of the tool (2) and the rotation center of the turntable (7) and the axis of the milling axis (1) are obtained, and the spatial position calibration of the milling axis (1) is completed.

2. The method for calibrating the spatial position of the milling axis of a machine tool for processing complex micro components based on trial cutting and tool setting according to claim 1 is characterized in that: In step S300, it specifically includes: S310, taking the rotation center of the turntable (7) as a reference, and obtaining the distribution diagram of the three tool setting completion points relative to the rotation center of the turntable (7) from the tool tip position coordinates when the three tool setting are completed, S320. Based on the position calibration algorithm, when the rotary table (7) is at the zero position and is deflected clockwise by α1, the distance O2A between the tool tips along the X-axis direction is (x2-x1), and the distance O1O2 between the two tool tips is: (1) Wherein, η represents the angle between the line connecting the tool tip and the rotation center of the rotary table (7) and the axis of the milling axis (1) when the rotary table (7) is at the zero point tool setting; The length of the line connecting the tool tip and the rotation center of the rotary table (7) is: (2) Wherein, O1C represents the line between the tool tip and the axis of the turntable (7) when the turntable (7) is at the zero position; O2C represents the line between the tool tip and the axis of the turntable (7) when the turntable (7) rotates clockwise by α1; When the rotary table (7) is at the zero position and deflected counterclockwise by α2, the distance O1B between the tool tips along the X-axis direction is (x1-x3), and the distance O1O3 between the tool tips is: (3) in, It represents the angle between the line connecting the two tool tip points O1O3 and the negative direction of the X axis when the rotary table (7) is at the zero point and the tool is deflected α2 counterclockwise; At this time, the length of the line connecting the tool tip and the rotation center of the rotary table (7) is: (4) Wherein, O3C represents the line connecting the tool tip and the axis of the rotary table (7) when the rotary table (7) rotates α2 counterclockwise for tool setting; From formula (1) and formula (2), we can get: (5) From formula (3) and formula (4), we can get: (6) When the rotary table (7) is at the zero point tool setting, the angle β between the line connecting the tool tip and the rotary table (7) rotation center and the axis of the milling axis (1) is: (7) When the rotary table (7) is at the zero position for tool setting, the distance CP between the rotary center and the axis of the milling axis (1) is: (8) According to the distribution diagram of S310: (9) S330, calibrate the spatial position of the milling axis (1) based on the functional relationship between the tool tip points in the three positions of the rotary table (7), and obtain the following two expressions of the same line segment O1C in the triangle O1O2C and the triangle O1O3C using formulas (5) and (6) in step S320: (10) Combining formula (9) and formula (10), we get: (11) (12) S340, η obtained in step S330 and , substitute into formula (5) to obtain the distance O1C between the tool tip and the rotation center of the turntable (7) when the turntable (7) is at the zero position; substitute into formula (7) to obtain the angle β between the line connecting the tool tip and the rotation center and the axis of the milling axis (1) when the turntable (7) is at the zero position; substitute into formula (8) to obtain the distance CP between the rotation center of the turntable (7) and the axis of the milling axis (1), and complete the spatial position calibration of the milling axis (1).

3. The method for calibrating the spatial position of the milling axis of a machine tool for processing complex and small components based on trial cutting and tool setting according to claim 2, characterized in that: In step S120, the initial jog step length is 10°, and when the axis of the milling shaft (1) is nearly parallel to the moving direction of the Z axis, the jog step length is reduced to 2°.

4. The method for calibrating the spatial position of the milling axis of a machine tool for processing complex and small components based on trial cutting and tool setting according to claim 3, characterized in that: In step S130, the movement stroke is -50mm~50mm. When the Z axis moves from -50mm to 50mm, if the reading of the inductive micrometer increases, the turntable (7) is rotated clockwise by a small angle and the rotation angle is recorded; if the reading of the inductive micrometer decreases, the turntable (7) is rotated counterclockwise by a small angle; after the rotation is completed, the full-stroke movement operation of the Z axis is continued to be performed, and the change of the reading of the inductive micrometer is observed.

5. The method for calibrating the spatial position of the milling axis of a machine tool for processing complex and small components based on trial cutting and tool setting according to claim 4, characterized in that: In steps S210-S230, the tool setting process includes adjusting the relative positions of the tool (2) and the workpiece (6) in the YZ vertical plane under the horizontal CCD camera (3), adjusting the tool (2) and the workpiece (6) to the same height, and then adjusting the relative positions in the XZ horizontal plane until the tool (2) and the workpiece (6) are located on the same axis.

6. The method for calibrating the spatial position of the milling axis of a machine tool for processing complex and small components based on trial cutting and tool setting according to claim 5, characterized in that: During the three tool setting processes, the tool (2) and the workpiece (6) are at the same height in the Y-axis direction.

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