Composite ballbar measuring device, data processing method and ballbar calibrator

Abstract

The present invention belongs to the technical field of machine tool error detection instruments, and particularly relates to a composite ballbar measuring device, a data processing method and a ballbar calibrator, comprising: a composite ballbar measuring device, arranged between a workbench and an electric spindle, the rotating end of the electric spindle is fixedly connected to one end of a rotary connecting plate, the other end of the rotary connecting plate is connected to one end of a first ballbar, the other end of the first ballbar is connected to the workbench; the middle of the first ballbar is connected to a second ballbar arranged vertically in space with the first ballbar, the second ballbar is connected to one end of a base rod, the other end of the base rod is fixed to the rotating end of the electric spindle; the base rod is vertical in space with the second ballbar; the rotating end of the electric spindle is transmission-connected with a rotation drive structure. And a data processing method and a ballbar calibrator for the composite ballbar measuring device. The present invention changes the single ballbar measurement result being affected by the axial error of the unexpected Z axis, making the original measurement result more accurate.

Description

Technical Field

[0001] The invention belongs to the technical field of machine tool error detection instruments, and in particular relates to a composite ballbar measuring device and a data processing method and a ballbar calibrator. Background Art

[0002] With the continuous development of modern manufacturing industry, the high-end technology field has increasingly higher requirements for the precision of parts processed by CNC machine tools. Effective detection of machine tool geometric errors has become one of the important links to improve machining accuracy. The ballbar has become one of the widely used instruments in the field of CNC machine tool precision detection due to its advantages such as high measurement accuracy, low hardware cost, high measurement efficiency, simple installation and convenient operation.

[0003] During the measurement process, the ballbar moves along the CNC machine tool in a circular arc in clockwise and counterclockwise directions, measures the radius error, and separates the machine tool's verticality, servo mismatch, reverse jump, straightness, scale mismatch and other error items through data processing and calculation. However, the ballbar can only measure the error change along the length of the rod, and can only analyze the arc trajectory on a single plane, and cannot simultaneously measure the axial error of the servo axis perpendicular to the plane (such as the Z axis). This undesired axial motion of the Z axis will lead to inaccurate ballbar measurement results. Therefore, a composite ballbar measurement device, data processing method and ballbar calibrator are urgently needed to solve this problem. Summary of the invention

[0004] The object of the present invention is to provide a composite ballbar measuring device, a data processing method and a ballbar calibrator to solve the above problems.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] A composite ballbar measuring device is arranged between a workbench and an electric spindle, wherein the rotating end of the electric spindle is fixedly connected to one end of a rotary connecting plate, the other end of the rotary connecting plate is connected to one end of a first ballbar via a standard ball fixing base, the other end of the first ballbar is connected to one end of a second ballbar via a connecting base cup, and is connected to the workbench via a magnetic fixing base;

[0007] The second ballbar is vertically arranged in space with respect to the first ballbar, the other end of the second ballbar is connected to one end of a base rod, and the other end of the base rod is fixedly connected to the rotating end of the electric spindle;

[0008] The base rod is vertical to the second ballbar in space;

[0009] The rotating end of the electric spindle is transmission-connected with a rotating drive structure.

[0010] Preferably, the base rod is axially connected to the rotating end of the electric spindle through a fixed locking nut.

[0011] Preferably, a through hole is provided at one end of the rotary connecting plate away from the electric spindle, and the standard ball fixing base is fixed in the through hole by bolts.

[0012] Preferably, the through hole is 100 mm away from the rotation axis of the rotating end of the electric spindle.

[0013] Preferably, the rotation driving structure includes a servo motor, a fixed end of the servo motor is fixed to the fixed end of the electric spindle through an electric spindle fixing frame, the output shaft sleeve of the servo motor is provided with one end of a belt, the other end of the belt is sleeved on the rotating shaft of the electric spindle, and the servo motor drives the rotating shaft of the electric spindle to rotate through the belt.

[0014] Preferably, the distance between the end of the base rod away from the electric spindle and the rotary connecting plate is 135 mm.

[0015] A ballbar calibrator, used for calibrating the first ballbar and the second ballbar, comprising a standard size calibration plate, the standard size calibration plate comprising a glass seat, a support seat and a half support seat are fixedly connected to the top of the glass seat, the support seat and the half support seat are symmetrically arranged, and a cylindrical magnet is embedded in the center of the support seat and the half support seat;

[0016] At least three supporting standard balls are fixedly connected at equal angles in the circumferential direction to the top of the supporting seat;

[0017] Two symmetrically arranged cylindrical guide pillars are fixedly connected to the top of the half support seat, and the cylindrical guide pillars are parallel to the connecting line between the support seat and the center of the half support seat. A limiting ball is provided between the two cylindrical guide pillars, and the limiting ball is embedded in the half support seat and is located on the side away from the support seat.

[0018] A data processing method for a composite ballbar measuring device, based on the composite ballbar measuring device, comprises the following steps:

[0019] Step 1, placing the device between the workbench and the electric spindle and performing a test to obtain data recorded by the first ballbar and the second ballbar respectively;

[0020] Step 2: record the data recorded by the first ballbar as , which is used to directly reflect the unexpected Z-axis axial measurement error. The data recorded by the second ballbar is recorded as , used to represent the ballbar radius result including the unexpected Z-axis axial measurement error;

[0021] Step 3: According to the formula , complete the Z-axis axial error compensation calculation, is the original measurement result of the second ballbar after compensation;

[0022] Step 4: Based on the original measurement results of the second ballbar and the standard ballbar data processing method, the precise rotation center is found after least squares fitting, and the accurate measurement radius error of the second ballbar is calculated, and the circular deviation and several machine tool error items are calculated.

[0023] Compared with the prior art, the present invention has the following advantages and technical effects:

[0024] The composite ballbar measuring device and data processing method and ballbar calibrator of the present invention can measure unexpected Z-axis axial errors and calculate more accurate ballbar raw measurement data, and then calculate ballbar measurement results. Specifically:

[0025] 1. The existing single ballbar measurement result is affected by the unexpected Z-axis axial error, and a measuring device that can accurately measure the Z-axis axial error is provided; in addition, the ballbar device that compensates for the Z-axis axial error can obtain more accurate original measurement results, and after standard ballbar data processing, multiple error items of the measured machine tool can be obtained.

[0026] 2. The Z-axis axial measuring end of the composite ballbar measuring device is directly connected to the magnetic fixing seat, so that the axial movement caused by the workbench in the rotation plane can be directly measured, overcoming the technical limitations of the indirect Z-axis displacement measurement solution.

[0027] 3. The key hardware is based on the existing ballbar device. Some hardware needs to be self-made. Combined with purchased standardized components, the comprehensive equipment can be easily built. Therefore, for terminal ballbar users, this improved instrument device does not require high-cost hardware investment and is easier to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative labor:

[0029] Figure 1 This is a schematic diagram of the installation of the composite ballbar of the present invention;

[0030] Figure 2 This is a schematic diagram of another angle composite ballbar installation of the present invention;

[0031] Figure 3It is a schematic diagram of the installation of the first ballbar and the second ballbar of the present invention;

[0032] Figure 4 This is a schematic diagram of the installation angle of the ballbar of the present invention;

[0033] Figure 5 This is a schematic diagram of calibration of the first ballbar of the present invention;

[0034] Figure 6 This is a schematic diagram of calibration of a second ballbar according to the present invention;

[0035] Figure 7 This is a schematic diagram of the structure of a standard size calibration plate of the present invention;

[0036] Among them, 1. workbench; 2. electric spindle; 3. first ballbar; 4. second ballbar; 5. base rod; 6. belt; 7. servo motor; 8. rotary connecting plate; 9. standard ball fixing base; 10. connecting base cup; 11. magnetic fixing seat; 12. fixing locking nut; 13. electric spindle fixing frame; 14. standard size calibration plate; 14-1. glass seat; 14-2. support standard ball; 14-3. support seat; 14-4. half support seat; 14-5. cylindrical guide column; 14-6. cylindrical magnet; 14-7. limit ball. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] Reference Figures 1 to 7 The present invention discloses a composite ballbar measuring device, which is arranged between a workbench 1 and an electric spindle 2, wherein the rotating end of the electric spindle 2 is fixedly connected to one end of a rotary connecting plate 8, the other end of the rotary connecting plate 8 is connected to one end of a first ballbar 3, and the other end of the first ballbar 3 is connected to the workbench 1;

[0040] A second ballbar 4 is connected to the middle of the first ballbar 3 and is vertically arranged in space with respect to the first ballbar 3. The second ballbar 4 is connected to one end of a base rod 5, and the other end of the base rod 5 is fixed to the rotating end of the electric spindle 2.

[0041] The base rod 5 is vertical to the second ballbar 4 in space;

[0042] The rotating end of the electric spindle 2 is transmission-connected with a rotating drive structure.

[0043] The present invention measures the displacement of the ballbar in the arc motion in a plane (such as XY) and the axial displacement of its vertical axis (Z axis) respectively by means of the first ballbar 3 and the second ballbar 4 during the arc motion. After data processing, the additional radial displacement of the ballbar in the XY plane caused by the axial displacement of the Z axis will be compensated, thereby obtaining a more accurate ballbar measurement result.

[0044] A further optimized solution is that the end of the second ballbar 4 away from the base rod 5 is connected to a connecting base cup 10 and a magnetic fixing seat 11, the magnetic fixing seat 11 is used to connect to the workbench 1, the connecting base cup 10 is used to connect to one end of the first ballbar 3, and the other end of the first ballbar 3 is connected to the end of the rotary connecting plate 8 away from the electric spindle 2 through a standard ball fixing base 9.

[0045] According to a further optimized solution, the base rod 5 is axially connected to the rotating end of the electric spindle 2 by fixing the locking nut 12 .

[0046] According to a further optimized solution, a through hole is provided at one end of the rotary connecting plate 8 away from the electric spindle 2, and the standard ball fixing base 9 is fixed in the through hole by bolts.

[0047] According to a further optimized solution, the distance between the through hole and the rotation axis of the rotation end of the electric spindle 2 is 100 mm.

[0048] A further optimized solution is that the rotation drive structure includes a servo motor 7, the fixed end of the servo motor 7 is fixed to the fixed end of the electric spindle 2 through the electric spindle fixing frame 13, the output shaft sleeve of the servo motor 7 is provided with one end of the belt 6, the other end of the belt 6 is sleeved on the rotating shaft of the electric spindle 2, and the servo motor 7 drives the rotating shaft of the electric spindle 2 to rotate through the belt 6.

[0049] According to a further optimized solution, the distance between the end of the base rod 5 away from the electric spindle 2 and the rotary connecting plate 8 is 135 mm.

[0050] The application platform of the composite ballbar device is a CNC machine tool or a processing platform based on an industrial robot, which includes the most basic elements, namely a processing workbench 1 and an electric spindle 2, and the composite ballbar device is installed between the workbench 1 and the electric spindle 2.

[0051] The rotary connecting plate 8 is fixed to the rotating end of the electric spindle 2 by screws, the servo motor 7 is fixed to the electric spindle fixing frame 13, the electric spindle fixing frame 13 is fixed to the fixed end of the electric spindle 2, and the servo motor 7 drives the rotating shaft of the electric spindle 2 to rotate through the belt 6.

[0052] The base rod 5 is fixed to the rotating end of the electric spindle 2 by fixing the locking nut 12, and the standard ball fixing base 9 is locked on the rotary connecting plate 8 by screws.

[0053] Specifically, one end of the rotary connecting plate 8 has a through hole, the distance between the hole and the rotary axis of the electric spindle is 10 mm, and the standard ball fixing base 9 is fixed to the rotary connecting plate 8 by screws.

[0054] Specifically, the base rod 5 is fixed on the electric spindle 2 by fixing the locking nut 12, and the side distance between the base rod 5 and the rotary connecting plate 8 is approximately equal to 135 mm. Since the standard ball fixed base 9 has the ability to adjust the local spatial position, the distance is an approximate number.

[0055] The magnetic fixing seat 11 is fixed on the workbench 1 by magnetic force.

[0056] One end of the second ballbar 4 is connected to the base rod 5, one side of the other end is connected to the magnetic fixing base 11, and the other side is connected to one end of the first ballbar 3 through the connecting base cup 10. The end of the first ballbar 3 is connected to the connecting base cup 10 through magnetism, and the other end of the first ballbar 3 is connected to the standard ball fixing base 9. The first ballbar 3 and the second ballbar 4 are installed to maintain a perpendicular relationship with each other.

[0057] The workbench 1 provides the arc motion required for the test during the measurement process; the servo motor 7 drives the rotating end of the electric spindle 2 to perform a rotary motion through the belt 6, and by setting the corresponding rotary speed, the rotary speed of the rotating end of the electric spindle 2 is equal to the rotary speed of the workbench 1.

[0058] Before use, the first ball bar 3 and the second ball bar 4 need to be calibrated, and the obtained calibration values ​​can be used for accurate calculation of subsequent ball bar measurement data.

[0059] A ballbar calibrator, used for calibrating the first ballbar 3 and the second ballbar 4, comprising a standard size calibration plate 14, the standard size calibration plate 14 comprising a glass seat 14-1, a support seat 14-3 and a half support seat 14-4 are fixedly connected to the top of the glass seat 14-1, the support seat 14-3 and the half support seat 14-4 are symmetrically arranged, and a cylindrical magnet 14-6 is embedded in the center of the support seat 14-3 and the half support seat 14-4;

[0060] At least three supporting standard balls 14-2 are fixedly connected at equal angles in the circumferential direction to the top of the supporting seat 14-3;

[0061] Two symmetrically arranged cylindrical guide pillars 14-5 are fixedly connected to the top of the half support seat 14-4. The cylindrical guide pillars 14-5 are parallel to the connecting line between the support seat 14-3 and the center of the half support seat 14-4. A limiting ball 14-7 is provided between the two cylindrical guide pillars 14-5. The limiting ball 14-7 is embedded in the half support seat 14-4 and is located on the side away from the support seat 14-3.

[0062] The standard size calibration plate 14 is composed of a glass base 14-1, a supporting standard ball 14-2, a supporting seat 14-3, a half supporting seat 14-4, a cylindrical guide column 14-5, a cylindrical magnet 14-6 and a limiting ball 14-7. The supporting seat 14-3 and the half supporting seat 14-4 are embedded in the glass base 14-1, and the supporting standard ball 14-2 is evenly distributed on the supporting seat 14-3 and the half supporting seat 14-4 at an equal angle of 120 degrees. The central part of the supporting seat 14-3 and the half supporting seat 14-4 is embedded with a cylindrical magnet 14-6 by gluing, and the other half supporting seat 14-4 is embedded with two cylindrical guide columns 14-5 fixed by gluing, and the two guide columns are parallel to each other. The limiting ball 14-7 ensures that when the ballbar is installed on the standard size calibration plate 14, a stable standard size can be obtained.

[0063] The measurement process of a composite ballbar measuring device is as follows:

[0064] 1. Install the rotary connecting plate 8 on the tool side of the electric spindle 2 by screws, install the electric spindle fixing frame 13 to the upper end of the electric spindle 2, and install the servo motor 7 and the belt 6;

[0065] 2. The base rod 5 is installed and fixed on the electric spindle 2 by fixing the locking nut 12. In the axial direction, the distance between the base rod 5 and the rotary connecting plate 8 is controlled to be about 135 mm;

[0066] 3. Install the standard ball fixing base 9 onto the slewing connecting plate 8, adjust one end of it to make it horizontal, and lock it;

[0067] 4. Install the magnetic fixing seat 11 on the workbench 1, install the calibration standard ball on its top, move the workbench 1 so that the other end of the standard ball contacts the top of the base rod 5, and then adjust the locking rod of the magnetic fixing seat 11 so that the standard ball, the magnetic fixing seat 11 and the base rod 5 fit perfectly, and record the position coordinates of the workbench 1 at this time;

[0068] 5. According to the recorded position coordinates, move the nominal measurement distance of the first ballbar 3, i.e. 100 mm, along the selected axis (e.g. X-axis), record the position coordinates, then install the calibration standard ball on the magnetic fixing base 11 and move 100 mm along the direction perpendicular to the selected axis (e.g. Z-axis). At this time, adjust the spatial position of the standard ball fixing base 9 so that it is in close contact with the calibration standard ball, and then adjust the locking rod to fix it; after completing this operation, move the workbench 1 in the opposite direction to the initial position.

[0069] 6. Install the second ballbar 4, one end of which is connected to the base rod 5 and the other end is connected to the magnetic fixing base 11; then install the first ballbar 3, one end of which is connected to the base cup 10 and the other end is connected to the standard ball fixing base 9.

[0070] 7. After determining the feed speed N1 (mm / min) of the ballbar measurement process, the required rotation speed N2 (mm / min) of the servo motor is calculated according to the diameter of the motorized spindle 2 and the pulley connected to the belt 6 (the large pulley is D1 and the small pulley is D2, in mm) and the measurement radius d (mm) of the ballbar. The calculation formula is as follows:

[0071]

[0072] 8. Perform a ballbar test based on the selected speed N2 in combination with the selected measurement parameters.

[0073] A data processing method for a composite ballbar measuring device, based on the composite ballbar measuring device, comprises the following steps:

[0074] Step 1: The device is set between the workbench 1 and the electric spindle 2 and tested to obtain data recorded by the first ballbar 3 and the second ballbar 4 respectively;

[0075] Step 2: record the data recorded by the first ballbar 3 as , which is used to directly reflect the unexpected Z-axis axial measurement error. The data recorded by the second ballbar 4 is recorded as , used to represent the ballbar radius result including the unexpected Z-axis axial measurement error;

[0076] Step 3: According to the formula , complete the Z-axis axial error compensation calculation, is the original measurement result of the second ballbar 4 after compensation;

[0077] Step 4: Based on the original measurement results of the second ballbar 4 and the standard ballbar data processing method, the precise rotation center is found after least squares fitting, and the accurate measurement radius error of the second ballbar 4 is calculated. According to the ISO230-4:2022 national standard, the circular deviation and several machine tool error items are calculated.

[0078] In the description of the present invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0079] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A composite ballbar measuring device, arranged between a workbench (1) and an electric spindle (2), characterized in that: The rotating end of the electric spindle (2) is fixedly connected to one end of a rotary connecting plate (8), the other end of the rotary connecting plate (8) is connected to one end of a first ballbar (3) via a standard ball fixing base (9), the other end of the first ballbar (3) is connected to one end of a second ballbar (4) via a connecting base cup (10), and is connected to the workbench (1) via a magnetic fixing base (11); The second ballbar (4) is vertically arranged with respect to the first ballbar (3), the other end of the second ballbar (4) is connected to one end of a base rod (5), and the other end of the base rod (5) is fixedly connected to the rotating end of the electric spindle (2); The base rod (5) is vertical to the second ballbar (4) in space; The rotating end of the electric spindle (2) is transmission-connected with a rotating drive structure.

2. A composite ballbar measuring device according to claim 1, characterized in that: The base rod (5) is axially connected to the rotating end of the electric spindle (2) via a fixed locking nut (12).

3. The composite ballbar measuring device according to claim 1, characterized in that: A through hole is provided at one end of the rotary connecting plate (8) away from the electric spindle (2), and the standard ball fixing base (9) is fixed in the through hole by means of bolts.

4. A composite ballbar measuring device according to claim 3, characterized in that: The through hole is 100 mm away from the rotation axis of the rotating end of the electric spindle (2).

5. The composite ballbar measuring device according to claim 1, characterized in that: The rotation drive structure comprises a servo motor (7), a fixed end of the servo motor (7) being fixed to a fixed end of the electric spindle (2) via an electric spindle fixing frame (13), an output shaft sleeve of the servo motor (7) being provided with one end of a belt (6), the other end of the belt (6) being sleeved on a rotating shaft of the electric spindle (2), and the servo motor (7) drives the rotating shaft of the electric spindle (2) to rotate via the belt (6).

6. The composite ballbar measuring device according to claim 1, characterized in that: The distance between the end of the base rod (5) away from the electric spindle (2) and the rotary connecting plate (8) is 135 mm.

7. A data processing method for a composite ballbar measuring device, based on a composite ballbar measuring device according to any one of claims 1 to 6, characterized in that: The steps include: Step 1: arranging the device between the workbench (1) and the electric spindle (2) and performing a test to obtain data recorded by the first ballbar (3) and the second ballbar (4); Step 2: record the data recorded by the first ballbar (3) as , which is used to directly reflect the unexpected Z-axis axial measurement error, and the data recorded by the second ballbar (4) is recorded as , used to represent the ballbar radius result including the unexpected Z-axis axial measurement error; Step 3: According to the formula , complete the Z-axis axial error compensation calculation, is the original measurement result of the second ballbar (4) after compensation; Step 4: Based on the original measurement result of the second ballbar (4), combined with the standard ballbar data processing method, the precise rotation center is found after least square fitting, and the accurate measurement radius error of the second ballbar (4) is calculated, and the circular deviation and several machine tool error items are calculated.

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