A method for machining internal threads of workpieces based on in-machine measurement of tool compensation values

Abstract

This invention discloses a method for machining internal threads in workpieces based on in-machine measurement of tool compensation values, belonging to the field of CNC machining technology. It involves designing a thread calibration component based on the workpiece to be measured, and then using the thread calibration component to perform standard thread machining. T The calibration of zero and diameter measurement, along with the optimized design of corresponding measurement steps, can accurately calculate the nominal value of the thread to be measured on the workpiece, thereby accurately measuring the tool feed and retraction compensation value during the thread workpiece machining process. This invention's workpiece internal thread machining method based on in-machine measurement of tool compensation values ​​is simple in procedure and convenient in operation. It effectively achieves accurate measurement of compensation values ​​in the tool feed and retraction directions during thread machining, providing a reliable basis for tool feed and retraction compensation during machining. This accurately realizes in-machine measurement and machining compensation of the thread workpiece, ensuring the machining accuracy of the thread workpiece, improving the yield rate of the thread workpiece, and has good practical value and application prospects.

Description

Technical Field

[0001] This invention belongs to the field of CNC machining technology, specifically relating to a method for machining internal threads of workpieces based on in-machine measurement of tool compensation values. Background Technology

[0002] In the field of CNC machining technology, it is very common to use lathes / machine tools to process threads. In order to ensure the accuracy of thread processing, it is often necessary to measure the processing dimensions of the thread.

[0003] Generally, thread ring gauges or thread plug gauges are used for thread machining on lathes. While this method can determine the quality of the thread machining to some extent, it cannot accurately measure the error value of the thread machining dimensions, making it difficult to provide accurate guidance for subsequent machining. Moreover, for certain specific workpieces, the threads to be machined may be special threads. In this case, conventional thread ring gauges or thread plug gauges cannot be accurately fitted, and custom-made ones are required. However, custom-made thread ring gauges / thread plug gauges not only increase the equipment cost for workpiece machining but also affect the machining efficiency of threaded workpieces due to the long customization cycle.

[0004] While existing technologies utilize tools such as thread micrometers to measure the pitch diameter of workpieces with corresponding pitches, a series of thread micrometers are typically required. Furthermore, this method is difficult to use for internal threads located deep from the end of the thread. Therefore, there is an urgent need to research new thread measuring equipment or methods to improve the efficiency and accuracy of thread machining. Summary of the Invention

[0005] In view of one or more of the above-mentioned defects or improvement needs of the prior art, the present invention provides a workpiece internal thread machining method based on in-machine measurement of tool compensation value. This method can accurately complete the machining error in the thread machining process through in-machine measurement, realize the accurate acquisition of tool machining compensation value, and improve the machining efficiency and machining accuracy of threaded workpieces.

[0006] To achieve the above objectives, one aspect of the present invention provides a method for machining internal threads of a workpiece based on in-machine measurement of tool compensation values. In this thread machining method, the spindle of the workpiece machining tool is driven by a servo motor with built-in spindle positioning function; it includes the following steps:

[0007] S1: Fabricate a thread calibration part based on the thread parameters of the workpiece to be measured; construct a coordinate system identical to that of the servo motor spindle. xyz Spatial coordinate system, where, z The axial direction is the horizontal direction parallel to the workpiece axis. x The axial direction is perpendicular to zThe vertical direction of the axis. y The axial direction is perpendicular to z The horizontal direction of the axis;

[0008] S2: Perform the following steps on the manufactured thread calibration parts. T Zero calibration is performed using the following formula. z Calibration of compensation values ​​measured in the axial direction:

[0009]

[0010] In the formula, δ z for z Measurement compensation value in the axial direction; T 0 is the nominal value for a standard thread; t 0' is the measured edge distance value when the probe actually measures the standard thread profile angle; d 0 represents the diameter of the probe; A 0 represents the included angle of the thread profile in a standard thread;

[0011] S3: Perform thread measurement on the machined workpiece. The thread measurement process is as follows:

[0012] S31: Move the probe ball of the workpiece probe along... z The shaft moves to the middle position of the pitch of the thread to be measured;

[0013] S32: Move the probe ball of the workpiece probe along... x Move along the axial direction to the pitch diameter of the thread to be measured. D 2 locations;

[0014] S33: Controls the probe's ball edge. z The probe moves along the axial direction to the positions where it touches the two side walls of the thread to be measured, reads the coordinate values ​​of the two positions, and calculates the actual edge distance value when the probe actually measures the thread profile angle of the thread to be measured, taking into account the diameter of the measuring ball. t ';

[0015] S34: The measured nominal value of the thread to be tested is calculated according to the following formula. T :

[0016]

[0017] In the formula, T The measured nominal value of the thread to be tested; A The value of the thread profile angle of the thread to be tested; δ z for z Measurement compensation value in the axial direction;

[0018] S4: Based on the measured nominal value of the thread to be tested. TCalculate the feed and retraction compensation values ​​for threaded workpieces during machining. δ The calculation formula is as follows:

[0019]

[0020] S5: Dynamically compensate thread cutting tools based on the feed / retraction compensation values ​​obtained in S4. x The shaft machining parameters are determined, and the internal thread machining of the corresponding threaded workpiece is completed.

[0021] Another aspect of the present invention provides a method for machining internal threads of a workpiece based on in-machine measurement of tool compensation values, wherein the spindle of the workpiece machining tool is driven by a conventional motor without spindle positioning function; the method includes the following steps:

[0022] S1: Fabricate a thread calibration piece based on the thread parameters of the workpiece to be measured; construct... xyz Spatial coordinate system, where, z The axial direction is the horizontal direction parallel to the workpiece axis. x The axial direction is perpendicular to z The vertical direction of the axis. y The axial direction is perpendicular to z The horizontal direction of the axis;

[0023] S2: Perform thread calibration on the threaded parts. T Zero calibration is performed using the following formula. z Calibration of compensation values ​​measured in the axial direction:

[0024]

[0025] In the formula, δ z for z Measurement compensation value in the axial direction; T 0 is the nominal value for a standard thread; t 0' is the measured edge distance value when the probe actually measures the standard thread profile angle; d 0 represents the diameter of the probe; A 0 represents the included angle of the thread profile in a standard thread;

[0026] S3: The diameter of the threaded surface of the threaded calibration component is measured and calibrated using the following formula. x Measurement compensation value in axial direction δ x Calculation:

[0027]

[0028] In the formula, δ x for xMeasurement compensation value in the axial direction; D 'for z axial distance is Z The measured diameter of the thread measuring point with a diameter of 0; D 0 represents the theoretical diameter of the thread measuring point;

[0029] S4: Perform thread measurement on the machined workpiece. The thread measurement process includes the following steps:

[0030] S41: Move the probe ball of the workpiece probe along... z Axial movement Z A distance of 1 allows the measuring ball to be radially aligned with the position where the workpiece has a thread;

[0031] S42: Control the ball-measuring edge x The axis moves until it abuts the surface of the thread, obtaining a set of coordinate values. X 1, Z 1'), and obtain the midpoint of the pitch of the thread under test based on the coordinate value. z Axis coordinates Z m ;

[0032] when X 1= D 1, Z 1= Z At time 1', the measuring ball abuts against the minor diameter of the thread. Z m for:

[0033] Z m = Z 1+ P / 2

[0034] In the formula, D 1 represents the minor diameter of the thread to be tested; Z m When the probe moves from its initial position to the middle position of the pitch of the thread being measured... z Axis movement distance; Z 1 represents the position of the probe when it moves from its initial position to the point where the radial alignment of the thread to be measured is achieved. z Axis movement distance; P The pitch of the thread to be tested;

[0035] when X 1> D 1, Z 1> Z At time 1', the measuring ball contacts the side of the receiving thread that is away from the zero position of the movement. Z m for:

[0036]

[0037] when X 1> D 1, Z 1 < Z At time 1', the measuring ball abuts against the side of the receiving thread closest to the zero position of motion. Z m for:

[0038]

[0039] S43: Move the probe ball of the workpiece probe along... z The axis moves to Z m The corresponding position, and along x Move along the axial direction to the pitch diameter of the thread to be measured. D 2 locations;

[0040] S44: Controls the probe's ball edge. z The probe moves along the axial direction to the positions where it touches the two side walls of the thread to be measured, reads the coordinate values ​​of the two positions, and calculates the actual edge distance value when the probe actually measures the thread profile angle of the thread to be measured, taking into account the diameter of the measuring ball. t ';

[0041] S45: The measured nominal value of the thread to be tested is calculated according to the following formula. T :

[0042]

[0043] In the formula, T The measured nominal value of the thread to be tested; A The value of the thread profile angle of the thread to be tested; δ z for z Measurement compensation value in the axial direction;

[0044] S5: Based on the measured nominal value of the thread to be tested. T Calculate the feed and retraction compensation values ​​for threaded workpieces during machining. δ The calculation formula is as follows:

[0045]

[0046] S6: Dynamically compensate thread cutting tools based on the feed / retraction compensation values ​​obtained in S5. x The shaft machining parameters are determined, and the internal thread machining of the corresponding threaded workpiece is completed.

[0047] As a further improvement of the present invention, the preparation process of the thread calibration part in step S1 is as follows:

[0048] S11: Select a cylindrical body with an outer diameter larger than the major diameter of the internal thread of the workpiece to be measured. D ;

[0049] S12: A certain depth and width corresponding to the minor diameter of the internal thread of the workpiece to be measured are cut along the axial direction at one end of the cylinder. D 1. Slot;

[0050] S13: Based on the thread parameters of the workpiece to be measured, cut grooves along the grooves on two opposite sides of the groove wall. y Threaded groove extending from the shaft;

[0051] S14: Measure the thread groove dimensions of the manufactured thread calibration part. Once the measured dimensions of the thread groove meet the design dimensions, the optimally configured thread calibration part can be obtained.

[0052] As a further improvement of the present invention, the threaded grooves opened on the wall surface of each groove are respectively z At least two are arranged sequentially along the axial direction, and the threaded grooves on the walls of the two grooves are... x They are positioned opposite each other along the axial direction, and respectively along... y The axis extends through both sides of the column.

[0053] As a further improvement of the present invention, the thread parameters include at least the major diameter, minor diameter, pitch diameter, thread pitch, thread end distance, and thread angle.

[0054] As a further improvement of the present invention, step S2 is performed... T Before calibration, perform an alignment and clamping process for the threaded calibration component to ensure that the thread groove edge of the clamped threaded calibration component is aligned. y Axis extension, i.e., with xz The plane formed by the directions is perpendicular.

[0055] As a further improvement of the present invention, in step S3, diameter measurement calibration is performed on the two side walls of the tooth angle at multiple measurement points, and the result is obtained by averaging multiple measurement compensation values. x The final measurement compensation value in the axial direction.

[0056] The aforementioned improved technical features can be combined with each other as long as they do not conflict with each other.

[0057] In summary, the beneficial effects of the above-described technical solutions conceived by this invention compared with the prior art include:

[0058] (1) The workpiece internal thread machining method based on in-machine measurement tool compensation value of the present invention designs a thread calibration part according to the workpiece to be measured, and utilizes the spindle positioning function of the servo motor to accurately complete the machining of the standard thread on the thread calibration part. T0 calibration, when obtaining thread measurement z The axial compensation value is used to compensate for the calculation of the measured nominal value of the workpiece after machining, ensuring the measured nominal value. T The accuracy of the calculations provides a precise basis for compensation in the machining of threaded workpieces, ensuring the precision and efficiency of threaded workpiece machining.

[0059] (2) The workpiece internal thread machining method based on in-machine measurement tool compensation value of the present invention is used in designing thread calibration parts and performing standard thread machining. T Based on the initial calibration, further calibration is performed by measuring the diameter of the standard thread. Then, by optimizing the alignment control method between the workpiece probe and the intermediate pitch of the thread to be measured on the workpiece, the movement position of the workpiece probe can be accurately controlled without a main axis coordinate system, thus achieving the measured nominal value. T During the calculation process x Shaft compensation and z Shaft compensation accurately realizes the feed and retraction compensation values ​​of the workpiece under test when driven by a conventional motor, effectively improving the machining accuracy of threaded workpieces when machining a conventional motor-driven spindle.

[0060] (3) The workpiece internal thread machining method based on in-machine measurement of tool compensation value of the present invention has simple steps and convenient operation. It can effectively realize the accurate measurement of compensation value in the tool advance and retraction direction during the thread machining process, and provide a reliable basis for tool advance and retraction compensation during the machining process. Thus, it accurately realizes in-machine measurement and machining compensation of threaded workpiece, ensures the machining accuracy of threaded workpiece, improves the yield of threaded workpiece, and has good practical value and application prospects. Attached Figure Description

[0061] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0062] Figure 1 This is a flowchart of a workpiece internal thread machining method based on in-machine measurement of tool compensation values ​​in an embodiment of the present invention;

[0063] Figure 2 This is a front view of the thread calibration component in an embodiment of the present invention;

[0064] Figure 3 This is a side view of the thread calibration component in an embodiment of the present invention;

[0065] Figure 4 This is a standard thread in the embodiment of the present invention. TA schematic diagram of the zero calibration;

[0066] Figure 5 This is a schematic diagram illustrating the standard thread diameter measurement and calibration in an embodiment of the present invention;

[0067] Figure 6 This is a schematic diagram illustrating the measurement of the nominal value of the thread under test during servo motor driving in an embodiment of the present invention;

[0068] Figures 7-9 This is a schematic diagram illustrating the calculation of the midpoint of the pitch of the thread under test during ordinary motor drive in an embodiment of the present invention. Detailed Implementation

[0069] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0070] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0071] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0072] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0073] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0074] Example:

[0075] Please see Figure 1 The preferred embodiment of the workpiece internal thread machining method based on in-machine measured tool compensation value includes the following steps:

[0076] S1: Fabricate a thread calibration piece based on the thread parameters of the workpiece to be measured;

[0077] In a preferred embodiment, the thread of the workpiece to be measured is an internal thread formed on the workpiece, and the thread parameters include at least the major diameter of the thread. D , paths D 1. Median diameter D 2. Pitch P Thread end distance L 1 and tooth profile angle A 0.

[0078] Meanwhile, in the actual fabrication of the support thread calibration parts, the preferred manufacturing process is as follows:

[0079] S11: Select a cylindrical body with an outer diameter larger than the major diameter of the internal thread of the workpiece to be measured. D ;

[0080] S12: A certain depth and width corresponding to the minor diameter of the internal thread of the workpiece to be measured are cut along the axial direction at one end of the cylinder. D 1. Slot;

[0081] By constructing such Figure 2 , Figure 3 As shown xyz Coordinate system, where, z The axial direction is the horizontal direction parallel to the workpiece axis. x The axial direction is perpendicular to z The vertical direction of the axis. y The axial direction is perpendicular to z The horizontal direction along the axis. It's not difficult to see that the length of the completed slot is along... y The axis extends, and its width direction is x Axial direction;

[0082] When actually creating the slot, cutting is the preferred method. After creating the slot, a distance of [distance missing] is formed at one end of the column. D 1. The two groove walls.

[0083] S13: Based on the thread end distance, internal thread pitch, tooth thickness, and tooth angle of the threaded workpiece to be measured, cut along the groove on two opposite groove walls respectively. y Threaded groove extending from the shaft;

[0084] In a preferred embodiment, the threaded grooves formed on each groove wall are as follows: z At least two are arranged sequentially along the axial direction, for example, Figure 3 The two shown; simultaneously, the threaded grooves on the walls of the two grooves are... x Set directly opposite each other along the axial direction.

[0085] In actual grooving operations, the thread grooves are preferably created by wire cutting or grinding. The angle between the opposing groove walls in each groove is equal to the thread profile angle of the workpiece being measured. A 0.

[0086] Furthermore, in the preferred embodiment, the slot and each threaded groove are respectively along y The axial direction runs through both sides of the column. This opening method can effectively reduce the manufacturing difficulty of the threaded calibration parts, and can be accurately completed using conventional wire cutting methods.

[0087] S14: Measure the thread groove dimensions of the manufactured thread calibration part. Once the measured dimensions of the thread groove meet the design dimensions, the optimally configured thread calibration part can be obtained.

[0088] S2: Perform the following steps on the manufactured thread calibration parts. T 0 calibration;

[0089] Specifically, in the preferred embodiments TCalibration is accomplished using a workpiece probe, which includes a probe rod and a probe ball at the end of the probe rod. The probe ball contacts the corresponding measuring position to obtain the corresponding measurement value. This type of workpiece probe is relatively mature in the field of workpiece inspection. For example, it is used in patent document CN 114800044 A. Its application in the preferred embodiment is the same as the conventional application, so it will not be described in detail here.

[0090] More in detail, T 0 is the nominal value for a standard thread, which corresponds to the thread pitch diameter. D The distance between the two side walls of the tooth angle, such as Figure 3 As shown in the image.

[0091] Meanwhile, for the nominal value in the preferred embodiment T For 0, it satisfies the following formula:

[0092]

[0093] In the formula, T 0 is the nominal value for a standard thread; t 0 indicates the probe is located at the median diameter. D 2. Theoretical edge distance values ​​when the probe center is at the mean diameter position and it abuts against the two side walls of the tooth profile angle respectively; d 0 represents the diameter of the probe; A 0 represents the included angle of the standard thread profile.

[0094] Furthermore, the measured edge distance value is defined when the probe actually measures the standard thread profile angle. t 0' and standard margin value t Difference between 0 δ z This is the overshoot value of the mean diameter, i.e. z The measurement compensation value in the axial direction. That is:

[0095]

[0096] By combining the two formulas above, we can obtain the following calibration formula:

[0097]

[0098] By designing the above formula, the thread calibration part can be completed. T 0 calibration, obtained z Measurement compensation value in the axial direction.

[0099] More specifically, in practice T Before calibration, it is preferable to perform an alignment and clamping process for the threaded calibration part to ensure that the thread groove edge of the threaded calibration part is aligned after clamping. y Axis extension, i.e., with xzThe plane formed by the directions is perpendicular.

[0100] To ensure the accuracy of the alignment and clamping of the threaded calibration parts, it is preferable to have an alignment groove on at least one groove wall surface, the alignment groove being along... z It is opened in the axial direction, forming at least one alignment surface parallel to the z-axis direction; during actual clamping and positioning, the alignment surface is adjusted to be parallel to the z-axis direction. xz Once the planes are parallel, the thread calibration part can be aligned. Then, the thread calibration part is clamped and fixed using clamping devices.

[0101] S3: Measure and calibrate the diameter of the threaded surface of the threaded calibration component;

[0102] Specifically, when using a workpiece probe for measurement, it is preferable to calibrate the workpiece probe to the zero point position before testing, and then measure along... z Axis movement distance Z 0, thereby achieving the positioning of the measuring point, and then controlling the edge of the workpiece measuring head. x Move along the axis until the probe comes into contact with the corresponding thread surface to be measured.

[0103] In a preferred embodiment, z The zero position of the shaft is preferably set at the intersection of the centerline of the column and the slotted end face of the column, i.e., as shown below. Figure 3 shown O Point, at the distance from the thread end L 1. Pitch P Tooth angle A When parameters such as 0 are known, the probe edge of the workpiece can be determined. z Distance of movement in the axial direction Z 0, calculate the theoretical alignment point of the probe on the workpiece and the theoretical diameter of the corresponding thread measuring point. D 0, such as Figure 5 As shown in the image.

[0104] Furthermore, control the workpiece probe edge x Move along the axis until it contacts the thread surface to obtain the measured diameter value at that measurement position. D ', using the measured diameter value D 'Compared with theoretical diameter value D By comparing with 0, the diameter measurement overshoot value at that measurement location can be obtained, i.e. x Measurement compensation value in the axial direction δ x .

[0105]

[0106] In the formula, δ x for xMeasurement compensation value in the axial direction; D 'for z axial distance is Z The measured diameter of the thread measuring point with a diameter of 0; D 0 represents the theoretical diameter of the thread measuring point.

[0107] In actual calibration, for the same threaded surface, it is preferable to calibrate multiple measurement points on both sides of the tooth angle; furthermore, at least one measurement point is selected on both the upper and lower sides of the pitch diameter (between the pitch diameter and the major diameter, and between the pitch diameter and the minor diameter).

[0108] Based on the relative coordinate system zero point of each measurement position z The theoretical diameter value for each measurement position is calculated by determining the axial distance. Then, the diameter is measured at each measurement position by controlling the workpiece probe, yielding the actual diameter value for each position. This allows us to obtain the final diameter value for each measurement position. x Measurement compensation value in the axial direction δ x By averaging multiple measurement compensation values, the final result is obtained. x Final measurement compensation value in the axial direction δ x .

[0109] S4: Perform thread measurement on the machined workpiece;

[0110] In a preferred embodiment, for thread measurement of the workpiece to be measured, there are two scenarios:

[0111] In the first scenario, the spindle of the workpiece machining tool is driven by a servo motor.

[0112] In this case, a schematic diagram of the workpiece thread measurement is shown below. Figure 6 As shown in the diagram, since the servo motor has its own spindle positioning function and a precise coordinate system, the workpiece probe can directly utilize the servo motor's coordinate system during actual operation. Therefore, the preferred thread measurement process for the workpiece is as follows:

[0113] S41: Move the probe ball of the workpiece probe along... z Axis movement distance Z m This ensures that the probe is radially aligned with the center of the pitch of the thread being measured;

[0114] S42: Move the probe ball of the workpiece probe along... x Move along the axial direction to the pitch diameter of the thread to be measured. D 2 locations;

[0115] S43: Controls the probe's ball edge. zThe probe moves along the axial direction to the positions where it touches the two side walls of the thread to be measured, reads the coordinate values ​​of the two positions, and calculates the actual edge distance value when the probe actually measures the thread profile angle of the thread to be measured, taking into account the diameter of the measuring ball. t ';

[0116] S44: The measured nominal value of the thread to be tested is calculated according to the following formula. T :

[0117]

[0118] In the formula, T The measured nominal value of the thread to be tested; A The value of the thread profile angle of the thread to be tested; δ z for z Measurement compensation value in the axial direction.

[0119] Obviously, for the above measurement scenario, it is not necessary to perform the thread face diameter measurement and calibration process of the thread calibration component in step S3. It is only necessary to perform the relevant processes in S1, S2 and S41 to S44 in sequence to accurately obtain the nominal value of the thread to be measured of the workpiece and complete the thread measurement process of the workpiece to be measured.

[0120] In the second scenario, the spindle of the workpiece machining tool is driven by a conventional motor.

[0121] In this situation, since ordinary motors do not have a spindle positioning function, it is impossible to move the probe to the middle position of the pitch of the thread to be measured as quickly and accurately as in step S41 above during actual measurement. Therefore, in the preferred embodiment, the following process is used to complete the correspondence between the workpiece probe and the middle position of the pitch of the thread to be measured:

[0122] S41': Position the probe ball of the workpiece along... z Axial movement Z A distance of 1 ensures that the radial direction of the measuring ball is aligned with the position where the workpiece has a thread.

[0123] S42': Control the edge of the measuring ball x The axis moves until it abuts the surface of the thread, obtaining a set of coordinate values. X 1, Z 1'), and obtain the thread to be tested based on the coordinate value. Z m Coordinate values ​​(middle distance of screw pitch from the initial position of the probe) z (axis spacing);

[0124] For the above coordinate values, there are three possibilities:

[0125] The first scenario, X 1=D 1, Z 1= Z 1'; At this point, the measuring ball abuts against the end of the thread tooth (corresponding to the minor diameter). D (position 1), such as Figure 7 As shown in the figure; in this case, the middle position of the pitch of the thread under test is... z Axis coordinates Z m for:

[0126] Z m = Z 1+ P / 2

[0127] In the formula, Z m When the probe moves from its initial position to the middle position of the pitch of the thread being measured... z Axis movement distance; Z 1 represents the position of the probe when it moves from its initial position to the point where the radial alignment of the thread to be measured is achieved. z Axis movement distance; P The pitch of the thread to be tested is denoted as .

[0128] The second scenario, X 1> D 1, Z 1> Z 1'; At this time, the measuring ball abuts against the left side of the thread being measured (the side away from the zero position of motion), as shown. Figure 8 As shown in the figure; in this case, the middle position of the pitch of the thread under test is... z Axis coordinates Z m for:

[0129]

[0130] The third scenario, X 1> D 1, Z 1 < Z 1'; At this time, the measuring ball abuts against the right side of the thread being measured (the side closest to the zero position of motion), as shown. Figure 9 As shown in the figure; in this case, the middle position of the pitch of the thread under test is... z Axis coordinates Z m for:

[0131]

[0132] Determine the thread to be tested Z m After obtaining the coordinate values, continue with the aforementioned steps S42~S44 to calculate the actual nominal value of the thread to be measured. T .

[0133] S5: Based on the measured nominal value of the thread to be tested. T The formula for calculating the tool feed / retraction compensation value during machining of threaded workpieces is as follows:

[0134]

[0135] In the formula, T This refers to the measured nominal value of the threaded workpiece; T 0 represents the standard nominal thread value for thread calibration components; δ For machining tools in x The feed / retract compensation value in the axial direction;

[0136] S6: Dynamically compensate thread cutting tools based on the feed / retraction compensation values ​​obtained in S5. x The shaft machining parameters are determined, and the internal thread machining of the corresponding threaded workpiece is completed.

[0137] It is understandable that during the actual machining of threaded workpieces, the aforementioned steps S4 to S6 can be performed at any time on the workpiece being machined to dynamically monitor the machining errors that occur during the thread machining process, providing a basis for compensation during the machining of threaded workpieces.

[0138] Obviously, the above method can guide both internal and external thread machining of threaded workpieces. It only requires switching between the major and minor diameters during the process, which can be accurately understood and operated by those skilled in the art, and will not be elaborated here.

[0139] The workpiece internal thread machining method based on in-machine measurement of tool compensation value in this invention has simple steps and is easy to operate. It can effectively realize the accurate measurement of compensation value in the tool approach and retraction direction during thread machining, providing a reliable basis for tool approach and retraction compensation during machining. Thus, it accurately realizes in-machine measurement and machining compensation of threaded workpieces, ensures the machining accuracy of threaded workpieces, improves the yield of threaded workpieces, and has good practical value and application prospects.

[0140] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for machining internal threads of a workpiece based on in-machine measurement of tool compensation values, characterized in that, In this thread machining method, the spindle of the workpiece machining tool is driven by a servo motor with built-in spindle positioning function; it includes the following steps: S1: Fabricate a thread calibration part based on the thread parameters of the workpiece to be measured; construct a coordinate system identical to that of the servo motor spindle. xyz Spatial coordinate system, where, z The axial direction is the horizontal direction parallel to the workpiece axis. x The axial direction is perpendicular to z The vertical direction of the axis. y The axial direction is perpendicular to z The horizontal direction of the axis; S2: Perform the following steps on the manufactured thread calibration parts. T Zero calibration is performed using the following formula. z Calibration of compensation values ​​measured in the axial direction: In the formula, δ z for z Measurement compensation value in the axial direction; T 0 is the nominal value for a standard thread; t 0' is the measured edge distance value when the probe actually measures the standard thread profile angle; d 0 represents the diameter of the probe; A 0 represents the included angle of the thread profile in a standard thread; S3: Perform thread measurement on the machined workpiece. The thread measurement process is as follows: S31: Move the probe ball of the workpiece probe along... z The shaft moves to the middle position of the pitch of the thread to be measured; S32: Move the probe ball of the workpiece probe along... x Move along the axial direction to the mean diameter of the thread to be measured. D 2 locations; S33: Controls the probe's ball edge. z The probe moves along the axial direction to the positions where it touches the two side walls of the thread to be measured, reads the coordinate values ​​of the two positions, and calculates the actual edge distance value when the probe actually measures the thread profile angle of the thread to be measured, taking into account the diameter of the measuring ball. t '; S34: The measured nominal value of the thread to be tested is calculated according to the following formula. T : In the formula, T The measured nominal value of the thread to be tested; A The value of the thread profile angle of the thread to be tested; δ z for z Measurement compensation value in the axial direction; S4: Based on the measured nominal value of the thread to be tested. T Calculate the feed and retraction compensation values ​​for threaded workpieces during machining. δ , which is calculated as follows: S5: Dynamically compensate thread cutting tools based on the feed / retraction compensation values ​​obtained in S4. x The shaft machining parameters are determined, and the internal thread machining of the corresponding threaded workpiece is completed.

2. A method for machining internal threads of a workpiece based on in-machine measurement of tool compensation values, characterized in that, In this thread-machining method, the spindle of the workpiece machining tool is driven by a standard motor without spindle positioning function; it includes the following steps: S1: Fabricate a thread calibration piece based on the thread parameters of the workpiece to be measured; construct... xyz Spatial coordinate system, where, z The axial direction is the horizontal direction parallel to the workpiece axis. x The axial direction is perpendicular to z The vertical direction of the axis. y The axial direction is perpendicular to z The horizontal direction of the axis; S2: Perform thread calibration on the threaded parts. T Zero calibration is performed using the following formula. z Calibration of compensation values ​​measured in the axial direction: In the formula, δ z for z Measurement compensation value in the axial direction; T 0 is the nominal value for a standard thread; t 0' is the measured edge distance value when the probe actually measures the standard thread profile angle; d 0 represents the diameter of the probe; A 0 represents the included angle of the thread profile in a standard thread; S3: The diameter of the threaded surface of the threaded calibration component is measured and calibrated using the following formula. x Measurement compensation value in axial direction δ x Calculation: In the formula, δ x for x Measurement compensation value in the axial direction; D 'for z axial distance is Z The measured diameter of the thread measuring point with a diameter of 0; D 0 represents the theoretical diameter of the thread measuring point; S4: Perform thread measurement on the machined workpiece. The thread measurement process includes the following steps: S41: Move the probe ball of the workpiece probe along... z Axial movement Z A distance of 1 allows the measuring ball to be radially aligned with the position where the workpiece has a thread; S42: Control the ball-measuring edge x The axis moves until it abuts the surface of the thread, obtaining a set of coordinate values. X 1, Z 1'), and obtain the midpoint of the pitch of the thread under test based on the coordinate value. z Axis coordinates Z m ; when X 1= D 1, Z 1= Z At time 1', the measuring ball abuts against the minor diameter of the thread. Z m for: Z m = Z 1+ P / 2 In the formula, D 1 represents the minor diameter of the thread to be tested; Z m When the probe moves from its initial position to the middle position of the pitch of the thread being measured. z Axis movement distance; Z 1 represents the position of the probe when it moves from its initial position to the point where the radial alignment of the thread to be measured is achieved. z Axis movement distance; P The pitch of the thread to be tested; when X 1> D 1, Z 1> Z At time 1', the measuring ball contacts the side of the receiving thread that is away from the zero position of the movement. Z m for: when X 1> D 1, Z 1< Z At time 1', the measuring ball abuts against the side of the receiving thread closest to the zero position of motion. Z m for: S43: Move the probe ball of the workpiece probe along... z The axis moves to Z m The corresponding position, and along x Move along the axial direction to the mean diameter of the thread to be measured. D 2 locations; S44: Controls the probe's ball edge. z The probe moves along the axial direction to the positions where it touches the two side walls of the thread to be measured, reads the coordinate values ​​of the two positions, and calculates the actual edge distance value when the probe actually measures the thread profile angle of the thread to be measured, taking into account the diameter of the measuring ball. t '; S45: The measured nominal value of the thread to be tested is calculated according to the following formula. T : In the formula, T The measured nominal value of the thread to be tested; A The value of the thread profile angle of the thread to be tested; δ z for z Measurement compensation value in the axial direction; S5: Based on the measured nominal value of the thread to be tested. T Calculate the feed and retraction compensation values ​​for threaded workpieces during machining. δ , which is calculated as follows: S6: Dynamically compensate thread cutting tools based on the feed / retraction compensation values ​​obtained in S5. x The shaft machining parameters are determined, and the internal thread machining of the corresponding threaded workpiece is completed.

3. The method for machining internal threads of a workpiece based on in-machine measurement of tool compensation values ​​according to claim 1 or 2, characterized in that, In step S1, the preparation process of the thread calibration part is as follows: S11: Select a cylindrical body with an outer diameter larger than the major diameter of the internal thread of the workpiece to be measured. D ; S12: A certain depth and width corresponding to the minor diameter of the internal thread of the workpiece to be measured are cut along the axial direction at one end of the cylinder. D 1. Slot; S13: Based on the thread parameters of the workpiece to be measured, cut grooves along the grooves on two opposite sides of the groove wall. y Threaded groove extending from the shaft; S14: Measure the thread groove dimensions of the manufactured thread calibration part. Once the measured dimensions of the thread groove meet the design dimensions, the optimally configured thread calibration part can be obtained.

4. The workpiece internal thread machining method based on in-machine measurement tool compensation value according to claim 3, characterized in that, The threaded grooves opened on the wall of each groove are as follows: z At least two are arranged sequentially along the axial direction, and the threaded grooves on the walls of the two grooves are... x They are positioned opposite each other along the axial direction, and respectively along... y The axis extends through both sides of the column.

5. The method for machining internal threads of a workpiece based on in-machine measurement of tool compensation values ​​according to claim 1 or 2, characterized in that, The thread parameters include at least the major diameter, minor diameter, pitch diameter, thread pitch, thread end distance, and thread angle.

6. The method for machining internal threads of a workpiece based on in-machine measurement of tool compensation values ​​according to claim 1 or 2, characterized in that, Perform in step S2 T Before calibration, perform an alignment and clamping process for the threaded calibration component to ensure that the thread groove edge of the clamped threaded calibration component is aligned. y Axis extension, i.e., with xz The plane formed by the directions is perpendicular.

7. The workpiece internal thread machining method based on in-machine measurement tool compensation value according to claim 2, characterized in that, In step S3, diameter measurement calibration is performed at multiple measurement points on both sides of the tooth angle, and the result is obtained by averaging multiple measurement compensation values. x The final measurement compensation value in the axial direction.

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