Milling cutter edge profile correction method, system and device based on interference error compensation

Abstract

The purpose of this invention is to provide a method, system, and apparatus for correcting the cutting edge profile of a milling cutter based on interference error compensation. The method includes: constructing a standard thread surface based on standard thread profile parameters to obtain a standard thread model; constructing a thread milling cutter cutting edge profile curve according to production needs to obtain a thread milling envelope surface and acquire the machined thread model; constructing an interference error model using the standard thread surface and the thread milling envelope surface; and correcting the machined thread model using the interference error model until the interference error of the milling cutter cutting edge profile meets the workpiece's accuracy requirements. The method described in this invention not only quickly yields the milling cutter cutting edge profile dimensions that meet accuracy requirements, but also has wide applicability. It can be used to correct various thread shapes regardless of pitch, hole diameter, or hole depth, thereby improving machining accuracy.

Description

Technical Field

[0001] This invention relates to the field of machining internal threads of helical pairs in helical transmissions, specifically to a method, system, and apparatus for correcting the cutting edge profile of a milling cutter based on interference error compensation. Background Technology

[0002] Trapezoidal threads offer good processability, high root strength, good centering, high pitch diameter strength, and good wear resistance, making them suitable for most applications requiring significant transmission force. However, precision machining of trapezoidal helical internal threads remains a challenging task in production. Insufficient machining accuracy can affect transmission accuracy and load-bearing capacity. Machining high-precision trapezoidal internal threads, however, often means high cost, low efficiency, or even complete impossibility, especially for nuts with large leads, small inner diameters, and deep holes. Traditional manufacturing methods for turning large-lead threads are extremely inefficient. Ordinary thread milling is further divided into two types based on the tool-workpiece position: one where the tool centerline is not parallel to the internal thread axis, creating an angle, which can lead to collisions and interference when machining deep internal threads; and another where the tool centerline is parallel to the internal thread axis, but this method easily produces significant thread profile errors, i.e., machining interference errors, and is not applicable to precision internal thread machining. While whirl milling can precisely mill internal threads, it remains ineffective for large-lead, deep internal threads.

[0003] In summary, conventional thread milling has significant errors and cannot achieve precision internal thread milling. Research and analysis show that the interference error generated by conventional thread milling can be greatly improved by modifying the cutting edge profile of the milling cutter. Therefore, an efficient method for modifying the milling cutter profile is urgently needed. Summary of the Invention

[0004] The purpose of this invention is to provide a method, system, and apparatus for correcting the cutting edge profile of a milling cutter based on interference error compensation, so as to solve at least one technical problem in the prior art.

[0005] The technical solution of this invention is:

[0006] A method for correcting the cutting edge profile of a milling cutter based on interference error compensation includes:

[0007] Based on the standard thread profile parameters, a standard thread surface is constructed to obtain a standard thread model;

[0008] Based on production needs, construct the profile curve of the thread milling cutter to obtain the thread milling envelope and acquire the processed thread model.

[0009] An interference error model is constructed using the standard thread surface and the thread milling envelope surface.

[0010] The interference error model is used to correct the machined thread model until the interference error of the milling cutter's cutting edge profile meets the workpiece's accuracy requirements.

[0011] The construction of the interference error model using the standard thread surface and the thread milling envelope includes:

[0012] By intersecting the reference plane with the standard thread surface and the thread milling envelope surface in sequence, the standard thread profile curve and the actual thread profile curve are obtained respectively, and an interference error model is constructed based on these two curves.

[0013] The construction of the interference error model includes:

[0014] Let the standard thread surface be LWM t The thread milling envelope is BLM; the datum plane is XOZ.

[0015] The thread milling envelope plane BLM intersects with the reference plane XOZ, resulting in the thread milling cutter machining envelope BLX:

[0016]

[0017] In the formula, the rotation angle θ of the thread end mill is related to time t and the thread end mill tooth profile height z. m The function, i.e.: θ(t, z) m )=-arcsin[R c ×sin(Ω×t) / r m (z m )]; i is the unit vector in the X direction; k is the unit vector in the Z direction; Ω is the angular velocity of the thread milling cutter's revolution; r m The profile curve of the thread milling cutter; R c Let t be the radius of the milling machining path, and t be the time.

[0018] The machining envelope BLX of a thread milling cutter is composed of a cluster of curves. Let the cutting edge profile curve of the thread milling cutter be r. m (z m ), then r m (z m Each point on the curve corresponds to a family of curves on the thread milling cutter machining envelope BLX. By finding the actual thread profile curve GSX tangent to any of these curve families, the expression for GSX is obtained. Therefore, by taking the partial derivative of BLX and setting its determinant to zero, the following can be derived:

[0019] Where, f(z) m (z) represents the amount of time t in the axial direction. m The expression, BLX(t, z) mThe quantity z in the axial direction of the thread milling cutter machining envelope BLX is a function of time t. m The expression.

[0020] f(z) m Substitute back to BLX(t, z) m Eliminating 't' yields the actual thread profile curve GSX as follows:

[0021] GSX(z m )=BLX(f(z m ), z m );

[0022] Using the standard thread curve LW t The radial and axial distances between the actual thread profile curve GSX and the actual thread profile curve GSX, i.e., the radial and axial interference errors E during the thread milling process. r E z They are respectively:

[0023] E r (z)=GSX(z)-LW t (z);

[0024] E z (z)=zz * ;

[0025] GSX(z)=LW t (z * );

[0026] Where z is the value at any point along the axis; * For LW t (z * When LW equals GSX(z) t (z * The value in the axial direction corresponding to ); GSX(z) is the radial r value corresponding to the actual thread profile curve GSX at point z; LW t (z) represents the radial r value corresponding to the standard thread curve at point z; LW t (z * Standard thread curve LW t In z * The corresponding radial direction value r * Furthermore, its interference error E and average interference error are obtained. Maximum interference error E max , respectively.

[0027] E = E r sin15°;

[0028]

[0029] E max =max(E);

[0030] The milling cutter cutting edge profile correction method based on interference error compensation is characterized in that the step of constructing a standard thread surface based on standard thread profile parameters to obtain a standard thread model includes:

[0031] Establish an XOZ coordinate system with the radial direction as the R-axis and the axial direction as the Z-axis.

[0032] Based on the required dimensions of the workpiece to be processed, at least 6 feature points are established in the inflection point of the two-dimensional tooth profile curve and the starting and ending points of the unit curve, with one pitch as the unit.

[0033] In the XOZ coordinate system, any two adjacent feature points are connected according to the two-dimensional thread profile to form a piecewise function r. t (z t ), that is, r t (z t () is the two-dimensional profile curve equation of the standard thread tooth profile;

[0034] Based on the trapezoidal thread profile z t With radial coordinate r t Constructing a standard thread profile model LW t for:

[0035] LW t (z t )=[r t (z t ), z t ] T ;

[0036] According to the standard thread profile curve r t (z t The standard thread surface LQM is obtained by the rotational motion around the central axis of the internal thread and the synchronous Z-axis feed motion. t The parameter expression, i.e.

[0037]

[0038] Among them, t d θ represents the thread direction; φ represents the thread pitch; θ is the rotation angle of the thread profile about the central axis of the internal thread; R(Θ) is the coordinate transformation matrix, and its expression is:

[0039] Where θ is the rotation angle of the thread profile around the central axis of the internal thread.

[0040] The described method for correcting the cutting edge profile of a thread milling cutter based on interference error compensation involves constructing a thread milling cutter cutting edge profile curve according to production needs, thereby obtaining the thread milling cutter rotation profile surface LWM. m This leads to the thread milling envelope surface being BLM, which includes:

[0041] Establish at least 6 feature points, and connect any 2 adjacent feature points to form the thread milling cutter cutting edge profile curve r. m (z m If the initial cutting edge profile of the thread milling cutter is LW, then... m The mathematical model for is:

[0042] LW m (z m )=[r m (z m ), z m ] T ;

[0043] The thread milling cutter cutting profile curve r m (z m Rotational motion around the tool spindle can generate the rotational profile surface (LWM) of the thread milling cutter. m ,for:

[0044] LWM m (θ,z m )=R(θ)[r m (z m ), 0, z m ] T In the formula, θ is the rotation angle of the thread milling cutter;

[0045] Milling machining track radius R c for:

[0046] Where D2 and d2 are the thread pitch diameter and the thread milling cutter pitch diameter, respectively;

[0047] When the angular velocity Ω of the thread milling cutter about the central axis of the nut is determined by the feed per tooth f... t Calculated

[0048]

[0049] In the formula, m m For thread milling; n f f is the number of teeth on the thread milling cutter. t Feed per tooth; P is the pitch; R is the feed rate per tooth. C The milling machining path radius; ω is the angular velocity of the milling cutter's rotation, determined by the spindle speed v. n The calculation yields the following result:

[0050]

[0051] In the internal thread coordinate system O-XYZ, the parametric equation of the thread milling cutter machining trajectory MC is:

[0052] t d Indicates the direction of thread rotation;

[0053] In the internal thread reference coordinate system, the thread end mill machining envelope surface (BLM) is established as follows:

[0054] BLM(t, θ, z) m )=MC(t)+LWM m (θ,z m );

[0055] Among them, z m This is the amount in the axial direction of the milling cutter.

[0056] The milling cutter cutting edge profile correction method based on interference error compensation is characterized in that the step of correcting the machined thread model using the interference error model includes:

[0057] Obtain the machining interference error at any point on the actual thread profile curve GSX, excluding the machined fillet area, and compare this machining interference error with the accuracy requirements, including:

[0058] If the accuracy requirements are not met, the interference error of the feature points of the blade profile is calculated. After obtaining the interference error, it is decomposed into radial interference error and axial interference error. The axial interference error is then used to substitute back to the corresponding feature points for correction.

[0059] After correcting all the feature points, connect the points to form a new blade profile curve. Then, correct the new blade profile curve again using the interference error model until the machining accuracy requirements are met.

[0060] The milling cutter cutting edge profile correction method based on interference error compensation is characterized in that:

[0061] The interference error of the feature points of the blade profile is calculated using the following formula and then corrected:

[0062] in, For feature points N after n iterations mn The coordinates of E; Z This refers to axial interference error; The feature point N after the (n-1)th iteration mn The axial coordinates.

[0063] A thread milling cutter profile correction system based on interference error compensation, comprising the above-mentioned thread milling cutter profile correction method based on interference error compensation, including:

[0064] The basic parameter setting module is used to collect the milling thread hole diameter, pitch, and thread direction data; and based on the above data, to draw the standard thread profile curve and the initial milling cutter cutting edge profile curve.

[0065] The simulation process module interacts with the basic parameter setting module to obtain the standard thread model, the machined thread model, and the interference error model based on the standard thread profile curve and the initial milling cutter profile curve, respectively.

[0066] The cutting edge profile correction module interacts with the simulation process module to correct the machined thread model using the interference error model until the process error requirements are met.

[0067] An electronic device comprising:

[0068] Storage media, used to store computer programs

[0069] The processing unit exchanges data with the storage medium and executes the computer program to perform the steps of the milling cutter cutting profile correction method based on interference error compensation as described above when correcting the milling cutter cutting profile.

[0070] A computer-readable storage medium:

[0071] The computer-readable storage medium stores a computer program.

[0072] When the computer program is running, it executes the steps of the milling cutter cutting edge profile correction method based on interference error compensation as described above.

[0073] The beneficial effects of the present invention include at least the following:

[0074] The method described in this invention addresses the significant thread profile error that occurs when the tool centerline is parallel to the internal thread axis. First, a standard thread surface is constructed based on standard thread profile parameters to obtain a standard thread model. Then, according to production needs, a thread milling cutter profile curve is constructed to obtain the thread milling envelope surface, resulting in the machined thread model. Next, an interference error model is constructed using the standard thread surface and the thread milling envelope surface. Finally, the machined thread model is corrected using the interference error model until the interference error of the milling cutter profile meets the workpiece's accuracy requirements. This method not only quickly yields the milling cutter profile dimensions that meet accuracy requirements but also has wide applicability. It can be used to correct various thread shapes, regardless of pitch, hole diameter, or hole depth, thereby improving machining accuracy. Attached Figure Description

[0075] Figure 1 This is a system block diagram of the system described in this invention;

[0076] Figure 2 This is a schematic diagram showing the shape and dimensions of a trapezoidal thread.

[0077] Figure 3 A schematic diagram of the basic parameter setting module;

[0078] Figure 4 A comparison diagram of standard thread profiles and milling cutter tooth profiles;

[0079] Figure 5 This is a schematic diagram of a standard threaded helical surface;

[0080] Figure 6 This is a schematic diagram of the cutting envelope surface;

[0081] Figure 7 This is a schematic diagram of the interference model;

[0082] Figure 8 This is a diagram illustrating the corrected error.

[0083] Figure 9 A comparison of the milling cutter cutting edge profile before and after correction;

[0084] Figure 10 A flowchart illustrating the actual processing using the method described in this invention;

[0085] Figure 11 This is a comparison chart of the efficiency values ​​of the method described in this invention and traditional methods;

[0086] Figure 12 This is a comparison chart of the maximum contour error between the method described in this invention and the traditional method. Detailed Implementation

[0087] The present application will now be further described with reference to the accompanying drawings.

[0088] To address the problems of existing technologies, this embodiment presents a milling cutter cutting edge profile correction method based on interference error compensation, comprising the following steps:

[0089] Step 1: Based on the thread profile parameters of the national standard, construct the standard thread profile curve, then construct the standard thread surface, and perform mathematical modeling in mathematical modeling software to obtain the standard thread model;

[0090] Step 2: Construct the machined thread model: Based on the thread profile parameters of the national standard, construct the initial thread milling cutter profile curve, further construct the thread milling envelope surface, and perform mathematical modeling in mathematical modeling software to obtain the machined thread model;

[0091] Step 3: Constructing the interference error model: Construct the cross-sectional curves of the reference plane intersecting the standard thread surface and the thread milling envelope surface respectively, namely the standard thread profile curve and the actual thread profile curve. Construct the interference error model based on these two curves.

[0092] Step 4: Based on the interference error model constructed in Step 3, correct the original milling cutter cutting edge profile. Repeat Steps 1 to 3 to obtain the corrected interference error model. Then correct the milling cutter cutting edge profile until its interference error meets the workpiece's accuracy requirements.

[0093] Specifically, the construction of a standard thread model mainly includes the construction of the standard thread profile curve and the standard thread surface. The construction of the standard thread profile curve requires first establishing feature points based on the trapezoidal thread outline dimensions and shape in the national standard, and then connecting the points to form a line to form the standard thread profile curve. The standard thread surface is formed by accumulating the standard thread curve around the axis and along the helix.

[0094] The construction of the resulting thread model mainly includes the initial milling cutter profile curve, the milling cutter rotation surface, and the thread milling envelope. The initial milling cutter profile curve is formed by establishing feature points according to the dimensions and shape of the national standard and then connecting the points to form a line. The milling cutter rotation surface is formed by rotating the milling cutter profile surface around the milling cutter axis, i.e., multiplying it by the rotation matrix of the corresponding milling cutter axis. The thread milling envelope is formed by gradually accumulating the milling cutter rotation surface along the tool machining trajectory.

[0095] The construction of the interference error model mainly includes the construction of the reference plane, the standard thread profile curve and the actual thread profile curve, and the construction of the interference error model. The reference plane can be any plane passing through the axis and parallel to the axial direction. The standard thread profile curve is directly obtained by intersecting the reference plane with the standard thread surface. However, the actual thread profile curve cannot be directly obtained by intersecting the reference plane with the thread milling envelope surface, because the intersection of the reference plane and the thread milling envelope surface results in a series of envelope curves. By finding the tangents to these envelope curves, the actual thread profile curve is obtained. The construction of the interference error model involves comparing the standard thread profile curve and the actual thread profile curve to find the deviation. At the same time, in order to facilitate the correction of the milling cutter profile, the interference error is decomposed into radial interference error and axial interference error according to geometric relationships.

[0096] The above-mentioned method of finding the tangent to the envelope curve can be further simplified in mathematical modeling software such as MATLAB. That is, the intersection point is obtained by the intersection of the reference plane and the thread milling envelope surface, the outermost point is selected, and the actual thread profile curve is generated by fitting the curve, which greatly improves the calculation efficiency.

[0097] The above-mentioned correction of the milling cutter's cutting edge profile is based on interference error correction. Interference error can be divided into radial interference error and axial interference error. Radial interference error can be eliminated by adjusting the tool's machining path radius, while axial interference error requires correction of the two side edges of the milling cutter. In addition, to facilitate the correction of the milling cutter's cutting edge profile, the cutting edge is composed of straight lines, without arcs or curves. Therefore, in the interference error model, the radial interference error is calculated at two feature points on each side and compensated to the corresponding position of the cutting edge to form a new cutting edge. The interference error model is then constructed with the new cutting edge until the interference error meets the accuracy requirements, thereby realizing the correction of the milling cutter's cutting edge profile.

[0098] During the above-mentioned milling cutter profile correction cycle, the machining radius appears at the root of the actual thread profile, which greatly affects the machining accuracy. Therefore, the tool path radius needs to be compensated for the machining radius. That is, the milling depth is further increased in the radial direction until the machining radius does not interfere with the use of the helical drive pair. At the same time, the milling cutter edge also needs to be adjusted accordingly.

[0099] This embodiment further details the above steps:

[0100] Specific Implementation Example I:

[0101] Step 1: Based on the thread profile parameters of the national standard, construct the standard thread profile curve, then construct the standard thread surface, and perform mathematical modeling in mathematical modeling software to obtain the standard thread model, including:

[0102] Establish an XOZ coordinate system with the radial direction as the R-axis and the axial direction as the Z-axis.

[0103] Based on the required dimensions of the workpiece to be processed, at least 6 feature points are established in the inflection point of the two-dimensional tooth profile curve and the starting and ending points of the unit curve, with one pitch as the unit.

[0104] In the XOZ coordinate system, any two adjacent feature points are connected according to the two-dimensional thread profile to form a piecewise function r. t (z t ), that is, r t (z t () is the two-dimensional profile curve equation of the standard thread tooth profile;

[0105] Based on the trapezoidal thread profile z t With radial coordinate r t Constructing a standard thread profile model LW t for:

[0106] LW t (z t )=[r t (z t ), z t ] T (1)

[0107] According to the standard thread profile curve r t (z t The standard thread surface LQM is obtained by the rotational motion around the central axis of the internal thread and the synchronous Z-axis feed motion. t The parameter expression, i.e.

[0108]

[0109] Among them, t d θ represents the thread direction; φ represents the thread pitch; θ is the rotation angle of the thread profile about the central axis of the internal thread; R(Θ) is the coordinate transformation matrix, and its expression is:

[0110]

[0111] Where θ is the rotation angle of the thread profile about the central axis of the internal thread.

[0112] Step Two: Constructing the Machined Thread Model: Based on the thread profile parameters of the national standard, construct the initial thread milling cutter profile curve, further construct the thread milling envelope surface, and perform mathematical modeling in mathematical modeling software to obtain the machined thread model, including:

[0113] At least 6 feature points are used, and the thread milling cutter cutting edge profile curve r is established by connecting any 2 adjacent feature points. m (z m If the initial cutting edge profile of the thread milling cutter is LW, then... m The mathematical model for is:

[0114] LW m (z m )=[r m (z m ), z m ] T (4)

[0115] The thread milling cutter cutting profile curve r m (z m Rotational motion around the tool spindle can generate the rotational profile surface (LQM) of the thread milling cutter. m ,for:

[0116] LWM m (θ,z m )=R(θ)[r m (z m )0, z m ] T (5)

[0117] In the formula, θ is the rotation angle of the thread milling cutter;

[0118] Milling machining track radius R c for:

[0119]

[0120] Where D2 and d2 are the thread pitch diameter and the thread milling cutter pitch diameter, respectively;

[0121] When the angular velocity Ω of the thread milling cutter about the central axis of the nut is determined by the feed per tooth f... t Calculated

[0122]

[0123] m m For thread milling; n f f is the number of teeth on the thread milling cutter. t Feed per tooth; P is the pitch; R is the feed rate per tooth. C The milling machining path radius; ω is the angular velocity of the milling cutter's rotation, determined by the spindle speed v. m The calculation yields the following result:

[0124]

[0125] In the internal thread coordinate system O-XYZ, the parametric equation of the thread milling cutter machining trajectory MC is:

[0126]

[0127] Among them, t d Indicates the direction of thread rotation;

[0128] In the internal thread reference coordinate system, the thread milling envelope plane (BLM) is established as follows:

[0129] BLM(t, θ, z) m )=Mc(t)+LWM m (θ,z m (10)

[0130] Among them, z m This is the amount in the axial direction of the milling cutter.

[0131] Step 3: Constructing the Interference Error Model: Establish cross-sectional curves by intersecting the reference plane with both the standard thread surface and the thread milling envelope surface, i.e., the standard thread profile curve and the actual thread profile curve. Based on these two curves, construct the interference error model, including:

[0132] Let the standard thread surface be LWM t The thread milling envelope is BLM; the datum plane is XOZ.

[0133] The thread milling envelope plane BLM intersects with the reference plane XOZ, resulting in the thread milling cutter machining envelope BLX:

[0134]

[0135] In the formula, the rotation angle θ of the thread end mill is related to time t and the thread end mill tooth profile height z. m The function,

[0136] That is: θ(t, z) m )=-arcsin[R c ×sin(Ω×t) / r m (z m (12)

[0137] i is a unit vector in the X direction; k is a unit vector in the Z direction; Ω is the angular velocity of the thread milling cutter's revolution; r m The profile curve of the thread milling cutter; R c Let t be the radius of the milling machining path, and t be the time.

[0138] The machining envelope BLX of a thread milling cutter is composed of a cluster of curves. Let the cutting edge profile curve of the thread milling cutter be r. m (z m ), then r m (z mEach point on the curve corresponds to a family of curves on the thread milling cutter machining envelope BLX. By finding the actual thread profile curve GSX tangent to any of these curve families, the expression for GSX is obtained. Therefore, by taking the partial derivative of BLX and setting its determinant to zero, the following can be derived:

[0139]

[0140] Where, f(z) m (z) represents the amount of time t in the axial direction. m The expression; BLX(t, z) m The quantity z in the axial direction of the thread milling cutter machining envelope BLX is a function of time t. m The expression.

[0141] The actual thread profile curve GSX is obtained as follows:

[0142] GSX(z m )=BLX(f(z m ), z m (14)

[0143] Using the standard thread curve LW t The radial and axial distances between the actual thread profile curve GSX and the actual thread profile curve.

[0144] That is, the radial and axial interference errors E during the thread milling process. r E z They are respectively:

[0145] E z (z)=GSX(z)-LW t (z) (15)

[0146] E z (z)=zz * (16)

[0147] GSX(z)=LW t (z * (17)

[0148] Where z is the value at any point along the axis; * For LW t (z * When LW equals GSX(z) t (z * The value in the axial direction corresponding to ); GSX(z) is the radial r value corresponding to the actual thread profile curve GSX at point z; LW t (z) represents the radial r value corresponding to the standard thread curve at point z; LW t(z * Standard thread curve LW t In z * The corresponding radial direction value r * Furthermore, its interference error E and average interference error are obtained. Maximum interference error E max , respectively.

[0149] E = E r sin15° (18)

[0150]

[0151] E max =max(E) (20)

[0152] Step 4: Based on the interference error model constructed in Step 3, correct the original milling cutter cutting edge profile. Repeat Steps 1 to 3 to obtain the corrected interference error model, and then correct the milling cutter cutting edge profile again until its interference error meets the workpiece's accuracy requirements, including:

[0153] First, obtain the machining interference error at any point on the actual thread profile GSX, excluding the machined fillet area. Compare this machining interference error with the accuracy requirements. If the accuracy requirements are not met, calculate the interference error of the feature points of the cutting edge profile. After obtaining the interference error, decompose it into radial interference error and axial interference error. Substitute the axial interference error back to the corresponding feature points for correction. Specifically:

[0154] The interference error of the feature points of the blade profile is calculated using the following formula and then corrected:

[0155]

[0156] in, For feature points N after n iterations mn The coordinates of E; Z This refers to axial interference error; The feature point N after the (n-1)th iteration mn The axial coordinates.

[0157] Finally, after correcting all the feature points, the points are connected to form a new blade profile curve. The new blade profile curve is then corrected again using the interference error model until the machining accuracy requirements are met.

[0158] Specific Implementation Example II:

[0159] The present invention also provides an embodiment:

[0160] like Figure 1A thread milling cutter correction system based on interference error compensation and milling cutter profile is disclosed, based on the milling cutter profile correction method based on interference error compensation described in Specific Embodiment I. The system includes: a basic parameter setting module 100, a simulation process module 200, and a profile correction module 300. The basic parameter setting module 100 collects data on the milled thread bore diameter, pitch, and thread direction; and based on this data, draws a standard thread profile curve and an initial milling cutter profile curve. The simulation process module 200 interacts with the basic parameter setting module 100 to obtain a standard thread model, a machined thread model, and an interference error model based on the standard thread profile curve and the initial milling cutter profile curve, respectively. The profile correction module 300 interacts with the simulation process module 200 to correct the machined thread model using the interference error model until the process error requirements are met.

[0161] Specific examples:

[0162] Taking the correction of the cutting edge profile of a milling tool for a trapezoidal thread sliding helical pair as an example, the specific dimensions and shape of the trapezoidal thread are as follows: Figure 2 As shown, according to the national standard GB / T 5796.3-2005, a trapezoidal thread with a pitch of 6mm and a nominal diameter of 30mm is selected. The calculation is reproduced in MATLAB software according to the mathematical modeling process described above, and combined into a trapezoidal thread milling cutter correction program. For example... Figure 3 As shown, firstly, the corresponding thread parameters need to be entered in the basic parameter setting module, namely, the major diameter, minor diameter, pitch diameter, and tooth tip clearance parameters corresponding to the selected thread model according to the national standard GB / T5796.3-2005; at the same time, the machining process parameters, such as spindle speed, feed per tooth, number of teeth, and machining path radius, are set. Then, the standard thread profile curve and the initial milling cutter cutting edge profile curve corresponding to this model are generated, which can be determined according to the standard thread profile curve. Figure 4 As shown, after generating the contour curve in the basic parameter setting module 100, the trapezoidal thread can be used as the milling target in the simulation process module 200, such as... Figure 5 , is a three-dimensional standard thread helical surface, which is formed by accumulating curves along the helical line of the thread, with a lead of 6, i.e., one pitch; Figure 6The thread milling envelope obtained by the milling cutter is composed of the milling cutter's rotating surface at each moment. The interference error corresponding to the initial milling cutter cutting edge profile curve is based on the standard thread helical surface and the thread milling envelope surface. The standard thread profile curve and the thread profile curve in the machined thread model are respectively intercepted by the standard thread helical surface and the thread milling envelope surface at the half-pitch to three-half-pitch range using the XOZ plane. Then, the interference error at each point within this range is obtained according to formulas 15-17 in specific embodiment I, and thus its interference model is obtained. Figure 7 As can be seen from the schematic diagram of the interference model, the interference error is mainly distributed on both sides of the thread tooth profile. Therefore, the subsequent milling cutter correction is mainly aimed at the side edge of the milling cutter.

[0163] After establishing the interference error model, the maximum and average interference errors of the model are calculated and recorded in the interference error record table. Simultaneously, the average interference error is compared to the input target accuracy. If the target accuracy is not met, the average interference errors of both cutting edges are calculated separately, and the corresponding cutting edges are corrected accordingly. Specifically, the interference is decomposed into radial and axial errors. The axial interference error is used to correct both cutting edges. Then, a new interference error model is established with the new cutting edge profile, and compared with the target accuracy again, until the target accuracy is met. Figure 8 As shown. In this embodiment, the selected thread milling cutter's cutting edge profile undergoes two iterations to obtain a milling cutter cutting edge profile that meets the target accuracy. The resulting thread profile is shown in the figure. Figure 9 As shown in the error diagram after correction, the two comparisons clearly show that, apart from the obvious machining radius at the tooth root, the two curves basically overlap, with an average interference error of 0.7μm. At the same time, the comparison of the milling cutter profile before and after correction shows that the correction of the milling cutter profile is mainly concentrated on the side cutting edge, narrowing the overall cutting edge, thereby achieving milling cutter edge correction with less interference in trapezoidal threads.

[0164] The specific program flow is as follows: Figure 10As shown, firstly, thread parameters and machining process parameters are set in the basic parameter setting module 100 to generate the standard thread profile curve and the milling cutter profile curve. It is worth noting that the initial milling cutter profile curve is generated based on the parameters of the standard thread profile curve; the only difference between the two is their radial position. Then, according to the modeling process of formulas 1-10 above, the standard thread helical surface and the thread milling envelope surface are generated. Since the actual thread profile curve process of formulas 11-14 above involves excessive computation, to simplify the program and reduce computation time, this embodiment uses a curve fitting method to generate the actual thread profile curve. This method mainly consists of three steps: first, the thread milling envelope surface is intercepted using a reference plane to obtain the intersection point; then, based on the boundary function built into MATLAB software, the outermost points among the intersection points are selected; finally, a curve is fitted based on these outermost points to obtain the actual thread profile curve. Figure 11 After verification, the results before and after program optimization were basically the same, but the program running time was shortened by one to two minutes. Then, to establish the interference error model and record the results, the interference error model was established according to formulas 15-20 above, and the maximum and average interference errors were recorded. The interference error, excluding the machining fillet area, was compared with the target accuracy. If the accuracy target was met, the target milling cutter cutting edge profile was output; if the accuracy target was not met, the feature point coordinates were corrected according to the interference error obtained in the previous step, as shown in formula 21. However, due to the existence of the actual thread profile curve, the specific interference error values ​​for the two feature points at the cutting edge could not be measured. Figure 2 As shown in the thread profile, the fillet is located at the tooth tip clearance a. c Therefore, in the actual thread profile curve (D1 / 2-a) c Two points are taken at point ) as the replacement feature points of the cutting edge. After all feature points are corrected, two feature points at the new cutting edge are calculated along the new side edge. Then, a new milling cutter cutting edge profile is generated and the next cycle is entered until the accuracy requirements are met.

[0165] After outputting the target milling cutter cutting edge profile, the specific shape and dimensions of the milling cutter cutting edge profile can be obtained based on the target milling cutter cutting edge profile. A new trapezoidal thread milling cutter can then be designed and manufactured. The milling cutter before modification, the modified milling cutter, and conventional CNC turning methods are used to machine a trapezoidal thread with a pitch of 6 mm and a hole depth of 50 mm. The machining time and machining errors are as follows: Figure 12 As shown, the modified tool not only meets the accuracy requirements but also improves the machining efficiency when machining trapezoidal threads, achieving efficient and high-precision milling of the internal threads of the trapezoidal thread helical pair.

[0166] Specific Implementation Example III:

[0167] The present invention also provides the following embodiments:

[0168] An electronic device includes a storage medium and a processing unit; wherein, when performing milling cutter cutting edge profile correction, the processing unit executes the computer program to perform the steps of the milling cutter cutting edge profile correction method based on interference error compensation as described in Specific Embodiment I.

[0169] A computer-readable storage medium storing a computer program; when the computer program is run, it executes the steps of the milling cutter cutting profile correction method based on interference error compensation as described in Specific Embodiment I.

[0170] In this invention, a computer-readable storage medium can be any tangible medium containing or storing a program that can be used by or in connection with an instruction execution system, apparatus, or device. In this invention, a computer-readable signal medium can include a data signal propagated in baseband or as part of a carrier wave, carrying computer-readable program code. Such propagated data signals can take various forms, including but not limited to electromagnetic signals, optical signals, or any suitable combination thereof. A computer-readable signal medium can also be any computer-readable medium other than a computer-readable storage medium, which can send, propagate, or transmit a program for use by or in connection with an instruction execution system, apparatus, or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including but not limited to: wireless, wireline, optical fiber, RF, etc., or any suitable combination thereof.

[0171] The above descriptions only cover a few specific embodiments of the present invention. However, the present invention is not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention. The above-mentioned serial numbers are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

Claims

1. A method for correcting the cutting edge profile of a milling cutter based on interference error compensation, characterized in that, include: Based on the standard thread profile parameters, a standard thread surface is constructed to obtain a standard thread model; Based on production needs, construct the profile curve of the thread milling cutter to obtain the thread milling envelope and acquire the processed thread model. An interference error model is constructed using the standard thread surface and the thread milling envelope surface. The machining thread model is corrected using the interference error model until the interference error of the milling cutter cutting edge profile meets the accuracy requirements of the workpiece. The construction of the interference error model includes: Let the standard thread surface be... The thread milling envelope is The reference plane is ; Then the thread milling envelope surface With reference plane The intersections yield the machining envelope of the thread milling cutter. for: ； In the formula, the rotation angle of the thread milling cutter is... It's about time. and thread milling cutter tooth profile height The function, that is: ; for Unit vector in the direction; for Unit vector in the direction; Angular velocity of the thread milling cutter's revolution; The profile curve of the thread milling cutter; For milling the track radius, For time; Thread milling cutter machining envelope Composed of a cluster of curves, let the profile curve of the thread milling cutter be... ,but Each point on the curve corresponds to the machining envelope of the thread milling cutter. A family of curves; through the actual thread profile curve. Tangent to any of the aforementioned curve families, we obtain The expression, using By taking the partial derivative and setting its determinant to zero, the following can be derived: ;in, For time Regarding the quantity in the axial direction The expression; Machining envelope for thread milling cutters Regarding time Amount in the axial direction The expression; Will Back to eliminate The actual thread profile curve can be obtained. for: ； Through standard thread curve Compared with the actual thread profile curve The radial and axial distances between them, i.e., the radial and axial interference errors during the thread milling process. , They are respectively: ； ； ； Where z is the value at any point along the axis; * For when equal hour The value in the corresponding axial direction; For the actual thread profile curve The value of r in the radial direction at point z; This represents the radial value of the standard thread curve at point z; Standard thread profile In z * The corresponding radial direction value r * The interference error is obtained. Average interference error Maximum interference error , respectively; ； ； 。 2. The milling cutter cutting edge profile correction method based on interference error compensation according to claim 1, characterized in that, The construction of the interference error model using the standard thread surface and the thread milling envelope includes: By intersecting the reference plane with the standard thread surface and the thread milling envelope surface in sequence, the standard thread profile curve and the actual thread profile curve are obtained respectively, and an interference error model is constructed based on these two curves. The process of generating the actual thread profile curve includes: Use a reference plane to cut the thread milling envelope surface to obtain the intersection point of the two; Select the point that is farther from the center of the thread among the above intersection points, that is, the outermost point; Based on the outermost points, a curve is fitted to obtain the actual thread profile curve.

3. The milling cutter cutting edge profile correction method based on interference error compensation according to claim 1, characterized in that, The process of constructing a standard thread surface based on standard thread profile parameters to obtain a standard thread model includes: Using the radial direction as Axis, axial direction as Axis, Establish Coordinate system; Based on the required dimensions of the workpiece to be processed, at least 6 feature points are established in the inflection point of the two-dimensional tooth profile curve and the starting and ending points of the unit curve, with one pitch as the unit. exist In a coordinate system, any two adjacent feature points are connected according to the two-dimensional thread profile to form a piecewise function. ,Right now The equation for the two-dimensional profile curve of the standard thread tooth profile; Based on trapezoidal thread profile radial coordinates Construct a standard thread profile model for: ； Through standard thread profile curve Rotational motion about the central axis of the internal thread, and synchronous rotation. Axial feed motion produces standard thread surface The parameter expression, i.e. ； in, Indicates the direction of thread rotation; θ is the thread pitch; ө is the rotation angle of the thread profile about the central axis of the internal thread. The coordinate transformation matrix is ​​expressed as follows: 。 4. The milling cutter cutting edge profile correction method based on interference error compensation according to claim 1, characterized in that, Based on production needs, the thread milling cutter cutting edge contour curve is constructed to obtain the thread milling cutter rotation contour surface. Thus, the thread milling envelope surface is obtained as ,include: Establish at least 6 feature points, and connect any 2 adjacent feature points to create the profile curve of the thread milling cutter. The initial cutting edge profile of the thread milling cutter The mathematical model for is: ； The profile curve of the thread milling cutter Rotational motion around the tool spindle can generate the rotational profile surface of the thread milling cutter. ,for: In the formula, This is the rotation angle of the thread end mill; Milling machining track radius for: ;in, and These are the thread pitch diameter and the thread milling cutter pitch diameter, respectively. When the angular velocity of the thread cutter's revolution around the nut's central axis... According to the feed per tooth Calculated ； In the formula, This is a thread milling method; f is the number of teeth on the thread milling cutter. t Feed per tooth; P is the pitch; R is the feed rate per tooth. C The radius of the milling machining path; ω is the angular velocity of the milling cutter's rotation. Based on spindle speed The calculation yields the following result: ； In the internal thread coordinate system In the middle, the machining trajectory of the thread milling cutter The parametric equation is: ;t d Indicates the direction of thread rotation; Establish the thread milling envelope in the internal thread reference coordinate system as follows: for: ； Among them, z m This is the amount in the axial direction of the milling cutter.

5. The milling cutter cutting edge profile correction method based on interference error compensation according to claim 1, characterized in that, The step of correcting the machined thread model using the interference error model includes: Obtain the actual thread profile curve The machining interference error at any point other than the machined fillet area is compared with the accuracy requirement, including: If the accuracy requirements are not met, the interference error of the feature points of the blade profile is calculated. After obtaining the interference error, it is decomposed into radial interference error and axial interference error. The axial interference error is then used to substitute back to the corresponding feature points for correction. After correcting all the feature points, connect the points to form a new blade profile curve. Then, correct the new blade profile curve again using the interference error model until the machining accuracy requirements are met.

6. The milling cutter cutting edge profile correction method based on interference error compensation according to claim 1, characterized in that: The interference error of the feature points of the blade profile is calculated using the following formula and then corrected: ;in, For iteration Subsequent feature points The coordinates of E; Z This refers to axial interference error; The feature points after the (n-1)th iteration The axial coordinates.

7. A thread milling cutter profile correction system based on interference error compensation, comprising the thread milling cutter profile correction method based on interference error compensation as described in any one of claims 1-6, characterized in that, include: The basic parameter setting module is used to collect the milled thread hole diameter, pitch, and thread direction data; and based on the above data, to draw the standard thread profile curve and the initial standard thread profile two-dimensional profile curve. The simulation process module interacts with the basic parameter setting module to obtain the standard thread model, the machined thread model, and the interference error model based on the standard thread profile contour curve and the initial standard thread profile two-dimensional contour curve, respectively. The cutting edge profile correction module interacts with the simulation process module to correct the machined thread model using the interference error model until the process error requirements are met.

8. An electronic device, characterized in that, include: Storage media, used to store computer programs The processing unit exchanges data with the storage medium and executes the computer program through the processing unit when correcting the milling cutter cutting edge profile to perform the steps of the milling cutter cutting edge profile correction method based on interference error compensation as described in any one of claims 1-6.

9. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program. When the computer program is run, it executes the steps of the milling cutter cutting profile correction method based on interference error compensation as described in any one of claims 1-6.

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