A special T-shaped probe pin calibration method based on in-machine measurement technology

Abstract

The application discloses a special T-shaped probe calibration method based on on-machine measurement technology, which comprises the following steps: obtaining the actual structure size of the special T-shaped probe; using the L-shaped part of the probe to detect a single side of a standard part; calculating the deflection angle of the L-shaped part of the probe; setting an initial angle according to the deflection angle; using a standard ring to measure the calibration amount of the same depth position of the column-shaped part of the probe; obtaining the calibration amount of the column-shaped part of the special T-shaped probe; using a standard part to perform comparison measurement; converting the measurement positions of the column-shaped part and the L-shaped part according to the structure size of the special T-shaped probe; modifying a measurement program; and calculating the calibration amount of the L-shaped part after measurement. Through the method, the calibration amounts of each part of the special T-shaped probe can be accurately obtained, subsequent processing and measurement precision can be improved, processing quality can be ensured, and production yield can be improved.

Description

Technical Field

[0001] This invention belongs to the field of in-machine measurement and inspection of CNC machine tools; it relates to a measurement and calibration method for a special T-shaped probe. Background Technology

[0002] Probe calibration is a preparatory step for the use of general probes. Calibration compensates for deviations between the probe head and the probe itself in the actual measurement value, improving the accuracy of subsequent workpiece measurements. T-shaped probes have a unique shape, consisting of cylindrical and L-shaped sections. Conventional calibration methods only address the cylindrical section, reflecting only the calibration value of that section. However, in practical applications, the measurement positions used with special T-shaped probes are not limited to the cylindrical section; the L-shaped section is more widely used in the chamfering measurement of mobile phone casings. If a conventional calibration value is used for both measurement positions, the actual measurement results will have significant errors, potentially leading to unstable or inaccurate measurement accuracy, affecting subsequent processing effects and quality. To address this issue, it is necessary to obtain the calibration values ​​for each part of the special T-shaped probe, and the methods for obtaining these values ​​will be studied. Summary of the Invention

[0003] This invention addresses the shortcomings of existing technologies by providing a calibration method for a special T-shaped probe based on in-machine measurement technology. This method enables the calibration of various parts of the special T-shaped probe and obtains accurate calibration values. This approach improves the accuracy of the T-shaped probe during application, ensuring the accuracy of subsequent measurement and processing results.

[0004] To achieve the above-mentioned technical objectives and effects, the technical solution of this invention includes the following steps:

[0005] Step 1: Obtain the actual structural dimensions of the special T-shaped probe, including the length and diameter of the cylindrical section (square column) and the length and diameter of the L-shaped section.

[0006] Step 2: Use the L-shaped part of the probe to perform single-sided probing of the standard part, and calculate the tool deflection angle of the L-shaped part of the probe based on the probing values.

[0007] Step 3: Set the initial orientation angle based on the tool deflection angle.

[0008] Step 4: Use a standard ring to perform calibration measurements at the same depth position on the cylindrical part of the probe, and obtain the calibration amount of the cylindrical part of the T-shaped probe.

[0009] Step 5: Use standard parts for comparative measurement. Based on the structural dimensions of the T-shaped probe, convert the measurement positions of the cylindrical and L-shaped parts, modify the measurement program, and perform comparative measurement to obtain the calibration quantity of the L-shaped part.

[0010] Step 1 includes the following:

[0011] (1) Measure the structural dimensions of the cylindrical part of the special T-shaped probe, including the length L of the cylinder. z and column dimension D z ;

[0012] (2) Measure the structural dimensions of the L-shaped part of the special T-shaped probe, and the length L of the square column. l and column dimension D l ;

[0013] Further structural dimensions of the special T-shaped probe can be obtained through measurements using a two-dimensional measuring instrument or manual measurement.

[0014] The calculation method for step 2 is as follows:

[0015] The L-shaped section of the special T-shaped probe is mounted on the probe rod. Since the angle at which each probe is mounted on the probe head is uncontrollable, and the deflection angle of this section cannot be visually determined after the machine tool grips the probe, and using a dial indicator is difficult, the gripping deflection angle should be confirmed before use. The calculation method for confirming the deflection angle is as follows:

[0016] (1) In the machine tool, use the probe to touch one side of the standard part (select the position of the one side according to the actual situation). Here, we take the -X direction as an example. Use the L-shaped part to touch along the -X direction to obtain the X value. L To obtain the coordinate values, only raise the Z-axis without moving the other two axes, and use a cylindrical probe to touch along the -X direction. z Coordinate values;

[0017] (2) The calculation method is as follows:

[0018] ① The X-direction deviation between the center point P0 of the T-shaped probe and the measuring corner point P1 of the L-shaped part: △X=X Z -X L ;

[0019] ② Calculate the distance between two points on the XOY plane projected from point P0 to point P1:

[0020] ③ Calculate the deflection angle of the L-shaped section relative to its initial position:

[0021] The initial position of the L-shaped section is 0° when it is aligned with the -X axis. The angle is positive when it rotates counterclockwise and negative when it rotates clockwise.

[0022] The above calculation plane is a top view, and the tool deflection angle of the L-shaped part is obtained through the above calculation.

[0023] The method for step 3 is as follows:

[0024] To ensure that the square column is aligned with the measurement direction when probing the L-shaped section in the ±X and ±Y directions, the variable representing the initial orientation angle in the machine tool is updated based on the tool deflection angle calculated above, or a value is assigned to this variable in the program, and the value of the initial orientation angle of the probe is used during measurement.

[0025] The method in step 4 includes:

[0026] (1) Install the standard ring on the machine tool with an installation accuracy of ≤0.002mm;

[0027] (2) Using the same depth position of the cylindrical part of the special T-shaped probe, measurements are taken in four directions (+X, -X, +Y, -Y) on the inner wall of the standard ring, as well as in the Z direction on the upper surface of the standard ring, to obtain the calibration values ​​of the cylindrical part of the T-shaped probe in different directions.

[0028] (3) Record the calibration value as follows: Z direction: △Z z +X direction: △X z -X direction: △X z ', +Y direction: △Y z -Y direction: △Y z '.

[0029] Furthermore, in subsequent workpiece measurements, it is required that the probe depth position be consistent with that used in this cylindrical probe to ensure more accurate measurement results.

[0030] The method in step 5 includes:

[0031] (1) Install standard parts on the machine tool with an installation accuracy of ≤0.002mm;

[0032] (2) Since the point position recorded by the special T-shaped probe used in the machine tool is a cylindrical part, if the L-shaped part is to be used for measurement, the measurement position of the cylindrical part needs to be converted to the measurement position of the L-shaped part according to the structural dimensions.

[0033] (3) Modify the position parameters of the measurement parts in the corresponding standard part measurement program to make the measurement of cylindrical parts and L-shaped parts continuous;

[0034] (4) Perform standard part comparison measurements to ensure that the cylindrical measurement position is consistent with the L-shaped measurement position;

[0035] (5) After obtaining the measurement data, first convert the L-shaped part data. After the conversion is completed, calculate and compare the cylindrical measurement data to obtain the deviation data between the two. The deviation Z direction is: △Z1; the +X, -X, +Y, and -Y directions are respectively: △X1, △X1', △Y1, and △Y1'.

[0036] (6) Based on the comparison measurement deviation results, the calibration quantity is converted to obtain the calibration quantity in each direction of the L-shaped part of the T-shaped probe, and the calibration quantity in the Z direction: △Z L The directional calibration values ​​for +X, -X, +Y, and -Y are respectively ΔX L , △X L '、△Y L , △Y L '.

[0037] The conversion formula is as follows:

[0038] ΔX L =ΔX1+ΔX z ,

[0039] ΔX L ′=ΔX1′+ΔX z ′

[0040] ΔY L =ΔY1+ΔY z ,,

[0041] ΔY L ′=ΔY1′+ΔY z ′

[0042] ΔZ L =ΔZ l +ΔZ z

[0043] Compared with the prior art, the present invention has at least the following beneficial effects:

[0044] The calibration of various parts of the special T-shaped probe yields compensation values ​​for each part at different angles, which is beneficial for subsequent workpiece measurements. Compared to using the same calibration value for all parts, which can lead to errors during workpiece measurement, this method avoids this situation, ensuring stable and micron-level accuracy in subsequent workpiece measurements.

[0045] This can further ensure the machining accuracy of the workpiece, guarantee production quality, and improve production yield. Attached Figure Description

[0046] Figure 1-1 This is a schematic diagram of the main structure of the special T-shaped probe;

[0047] Figure 1-2 This is a top view of the special T-shaped probe structure;

[0048] Figure 2-1 A schematic diagram showing the actual measured angle of the deflection angle of the L-shaped section;

[0049] Figure 2-2 A schematic diagram of the theoretical measurement angle of the deflection angle of the L-shaped section;

[0050] Figure 3 A schematic diagram for calculating the deflection angle of the L-shaped section;

[0051] Figure 4 Flowchart for calibration of special T-shaped probes;

[0052] Figure 5 This is a schematic diagram for comparing and measuring standard parts. Detailed Implementation

[0053] This paper presents a calibration method for a special T-shaped probe based on in-machine measurement technology. The main focus is on obtaining the calibration values ​​for various parts (cylindrical and L-shaped sections) of the special T-shaped probe. A comparative measurement method is applied to obtain the compensation amount for the L-shaped section of the special T-shaped probe. The aim is to enable accurate measurement compensation using any part of the probe in subsequent workpiece measurements, thereby improving workpiece measurement accuracy and ensuring machining quality.

[0054] A calibration method for a special T-shaped probe based on in-machine measurement technology includes the following steps:

[0055] Step 1: Obtain the actual structural dimensions of the special T-shaped probe, including the length and diameter of the cylindrical section (square column) and the length and diameter of the L-shaped section.

[0056] Step 2: Use the L-shaped part of the probe to perform single-sided probing of the standard part, and calculate the tool deflection angle of the L-shaped part of the probe based on the probing values.

[0057] Step 3: Set the initial orientation angle based on the tool deflection angle.

[0058] Step 4: Use a standard ring to perform calibration measurements at the same depth position on the cylindrical part of the probe, and obtain the calibration amount of the cylindrical part of the T-shaped probe.

[0059] Step 5: Use standard parts for comparative measurement. Based on the structural dimensions of the T-shaped probe, convert the measurement positions of the cylindrical and L-shaped parts, modify the measurement program, and perform comparative measurement to obtain the calibration quantity of the L-shaped part.

[0060] Step 1 includes the following:

[0061] (1) Measure the structural dimensions of the cylindrical part of the special T-shaped probe, including the length L of the cylinder. z and column dimension D z ;

[0062] (2) Measure the structural dimensions of the L-shaped part of the special T-shaped probe, and the length L of the square column. l and column dimension D l ;

[0063] Further structural dimensions of the special T-shaped probe can be obtained through measurements using a two-dimensional measuring instrument or manual measurement.

[0064] The calculation method for step 2 is as follows:

[0065] The L-shaped section of the special T-shaped probe is mounted on the probe rod. Since the angle at which each probe is mounted on the probe head is uncontrollable, and the deflection angle of this section cannot be visually determined after the machine tool has gripped the tool, and using a dial indicator is difficult, the probe deflection angle should be confirmed before use. The calculation method for confirming the deflection angle is as follows:

[0066] (1) In the machine tool, use the probe to touch one side of the standard part (select the position of the one side according to the actual situation). Here, we take the -X direction as an example. Use the L-shaped part to touch along the -X direction to obtain the X value. L To obtain the coordinate values, only raise the Z-axis without moving the other two axes, and use a cylindrical probe to touch along the -X direction. z Coordinate values;

[0067] (2) The calculation method is as follows:

[0068] ① The X-direction deviation between the center point P0 of the T-shaped probe and the measuring corner point P1 of the L-shaped part: △X=X Z -X L ;

[0069] ② Calculate the distance between two points on the XOY plane projected from point P0 to point P1:

[0070] ③ Calculate the deflection angle of the L-shaped section relative to its initial position:

[0071] The initial position of the L-shaped section is 0° when it is aligned with the -X axis. The angle is positive when it is counterclockwise and negative when it is clockwise.

[0072] The above calculation plane is a top view, and the tool deflection angle of the L-shaped part is obtained through the above calculation.

[0073] The method for step 3 is as follows:

[0074] To ensure that the square column is aligned with the measurement direction when probing the L-shaped section in the ±X and ±Y directions, the variable representing the initial orientation angle in the machine tool is updated based on the tool deflection angle calculated above, or a value is assigned to this variable in the program, and the value of the initial orientation angle of the probe is used during measurement.

[0075] The method in step 4 includes:

[0076] (1) Install the standard ring on the machine tool with an installation accuracy of ≤0.002mm;

[0077] (2) Using the same depth position of the cylindrical part of the special T-shaped probe, measurements are taken in four directions (+X, -X, +Y, -Y) on the inner wall of the standard ring, as well as in the Z direction on the upper surface of the standard ring, to obtain the calibration values ​​of the cylindrical part of the T-shaped probe in different directions.

[0078] (3) Record the calibration value as follows: Z direction: △Z z +X direction: △X z -X direction: △X z ', +Y direction: △Y z -Y direction: △Y z '.

[0079] Furthermore, in subsequent workpiece measurements, it is required that the probe depth position be consistent with that used in this cylindrical probe to ensure more accurate measurement results.

[0080] The method in step 5 includes:

[0081] (1) Install standard parts on the machine tool with an installation accuracy of ≤0.002mm;

[0082] (2) Since the point position recorded by the special T-shaped probe used in the machine tool is a cylindrical part, if the L-shaped part is to be used for measurement, the measurement position of the cylindrical part needs to be converted to the measurement position of the L-shaped part according to the structural dimensions.

[0083] (3) Modify the position parameters of the measurement parts in the corresponding standard part measurement program to make the measurement of cylindrical parts and L-shaped parts continuous;

[0084] (4) Perform standard part comparison measurements, and try to keep the cylindrical measurement position consistent with the L-shaped measurement position;

[0085] (5) After obtaining the measurement data, first convert the data of the L-shaped part. After the conversion is completed, calculate and compare the deviation data of the cylindrical measurement data to obtain the deviation data of the two. The deviation in the Z direction is: △Z l The directions of +X, -X, +Y, and -Y are respectively: △X l , △X l '、△Y l , △Y l '.

[0086] (6) Based on the comparison measurement deviation results, the calibration quantity is converted to obtain the calibration quantity in each direction of the L-shaped part of the T-shaped probe, and the calibration quantity in the Z direction: △Z L The directional calibration values ​​for +X, -X, +Y, and -Y are respectively ΔX L , △X L '、△Y L , △Y L '.

[0087] The conversion formula is as follows:

[0088] ΔX L =ΔX1+ΔX z ,

[0089] ΔX L ′=ΔX1′+ΔX z ′

[0090] ΔY L =ΔY1+ΔY z ,,

[0091] ΔY L ′=ΔY l +ΔY z ′

[0092] ΔZ L =ΔZ l +ΔZ z

[0093] Compared with the prior art, the present invention has at least the following beneficial effects:

[0094] The calibration of various parts of the special T-shaped probe yields compensation values ​​for each part at different angles, which is beneficial for subsequent workpiece measurements. Compared to using the same calibration value for all parts, which can lead to errors during workpiece measurement, this method avoids this situation, ensuring stable and micron-level accuracy in subsequent workpiece measurements.

[0095] This can further ensure the machining accuracy of the workpiece, guarantee production quality, and improve production yield.

Claims

1. A special T-shaped probe calibration method based on in-machine measurement technology, comprising the following steps: Step 1: Obtain the actual structural dimensions of the special T-shaped probe, including the length and diameter of the cylindrical section (square column) and the length and diameter of the L-shaped section. Step 2: Use the L-shaped part of the probe to perform single-sided probing of the standard part, and calculate the tool deflection angle of the L-shaped part of the probe based on the probing values. Step 3: Set the initial orientation angle based on the deflection angle. Step 4: Use a standard ring to perform calibration measurements at the same depth position on the cylindrical part of the probe, and obtain the calibration amount for the cylindrical part of the special T-shaped probe. Step 5: Use standard parts for comparative measurement. Based on the structural dimensions of the special T-shaped probe, convert the measurement positions of the cylindrical and L-shaped parts, modify the measurement program, and calculate the calibration quantity of the L-shaped part after measurement.

2. The special T-shaped probe calibration method according to claim 1, characterized in that, The specific details of step 1 are as follows: Measure the structural dimensions of the cylindrical portion of a special T-shaped probe, including the length L of the cylinder. z and column dimension D z ; Measure the structural dimensions of the L-shaped portion of the special T-shaped probe, including the length L of the square column. l and column dimension D l ; The structural dimensions of the special T-shaped probe can be obtained through a two-dimensional measuring instrument or by manual measurement.

3. The special T-shaped probe calibration method according to claim 1, characterized in that, The specific details of step 2 are as follows: In the machine tool, the probe touches one side of a standard part. The position of the single side is selected according to the actual angular deflection. Here, taking the -X direction as an example, the L-shaped part is used to touch along the -X direction to obtain the X value. L Coordinate values, only the Z-axis is raised, and the X-axis is obtained by touching the probe along the -X direction with a cylindrical stylus. z Coordinate values; The calculation method is as follows: ① The X-direction deviation △X between the center point P0 of the special T-shaped probe and the measurement corner point P1 of the L-shaped part; ② Calculate the distance ΔL between the two points P0 and P1 projected onto the XOY plane; ③ Calculate the deflection angle β of the L-shaped section relative to its initial position; When the L-shaped part is aligned with the -X axis, it is at its initial position of 0°. Counterclockwise angles are positive, and clockwise angles are negative. The above calculation plane is a top view, and the tool deflection angle of the L-shaped part is obtained through the above calculation.

4. The special T-shaped probe calibration method according to claim 3, characterized in that, Step 3 involves updating the initial angle of the probe orientation, which is the tool deflection angle obtained in Step 2.

5. The special T-shaped probe calibration method according to claim 1, characterized in that, Step 4 details are as follows: Install a standard ring on the machine tool with an installation accuracy of ≤0.002mm; Using a special T-shaped probe, measurements are taken at the same depth position on the cylindrical part of the standard ring in four directions (+X, -X, +Y, -Y) on the inner wall, as well as in the Z direction on the upper surface of the standard ring, to obtain the calibration values ​​of the cylindrical part in different directions. The calibrated quantity is recorded as follows: Z direction: △Z z +X direction: △X z -X direction: △X z ', +Y direction: △Y z -Y direction: △Y z '; In subsequent workpiece measurements, the probe depth position must be consistent with that used for the cylindrical probe.

6. The special T-shaped probe calibration method according to claim 5, characterized in that, Step 5 details are as follows: Standard parts are installed on machine tools with an installation accuracy of ≤0.002mm; Convert the measurement position of the cylindrical part to the measurement position of the L-shaped part; Modify the measurement position parameters in the corresponding standard part measurement program to perform continuous measurements of cylindrical and L-shaped parts. Perform comparative measurements of standard parts, keeping the measurement positions of the cylindrical and L-shaped parts as close as possible; After obtaining the measurement data, the data for the L-shaped section is first converted. After the conversion, the comparison deviation data is calculated to obtain the comparison deviation between the Z and XY directions. The Z-direction deviation is: △Z l The directions of +X, -X, +Y, and -Y are respectively: △X l , △X l '、△Y l , △Y l '; Based on the comparison measurement deviation results, the calibration values ​​are converted to obtain the calibration values ​​for each direction of the L-shaped part of the T-shaped probe, including the Z-direction calibration value: △Z L The directional calibration values ​​for +X, -X, +Y, and -Y are respectively ΔX L , △X L '、△Y L , △Y L '; The conversion formula is as follows:

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