A high-precision variable-section long thin rod parts processing device and processing method

Abstract

The invention discloses a high-precision variable-section long thin rod part processing device and a processing method. The processing device comprises a dividing plate, a main shaft, a tail center, a chuck, and a workbench. A tail center is arranged at one end of the workbench, and a dividing plate is arranged at the other end corresponding to the tail center. A chuck is arranged on the side of the dividing plate corresponding to the tail center, and a dividing servo motor for driving the chuck to rotate is arranged at the other end. The invention is characterized in that a main shaft connected to a numerically controlled milling machine is also arranged on the workbench, and a grinding wheel is arranged on the main shaft. The device is used to change the settings of the milling feed amount and the lateral movement of the milling cutter into the settings of the sanding arc angle, the quadratic fitting curve and other parameters. The invention adopts the chord-cut grinding wheel grinding technology to process the long thin rod parts, reduces the processing difficulty of the long thin rod parts, and improves the processing efficiency and the qualified rate.

Description

Technical Field

[0001] The invention relates to the technical field of parts processing, and in particular to a high-precision variable-section long thin rod parts processing device and a processing method. Background Art

[0002] Lathe is an important means of mechanical processing and is widely used in parts processing and manufacturing industries. Round rod-shaped parts are usually processed by lathe turning method, but for high-precision long and thin rods (L / d>20), lathe turning method can no longer meet the accuracy of the parts. Even if they are barely processed, the qualified rate will drop sharply as the rod diameter becomes thinner, and the scrap rate will increase significantly.

[0003] In important application fields such as nuclear reactors, there is a great demand for high-precision variable circular cross-section slender rod parts; for the processing of high-precision variable conical cross-section long slender rod parts, especially slender rod parts with a length greater than 400mm and a diameter of 4mm-5mm, lathe cutting, which has always been strong in processing cylindrical parts, has become incapable.

[0004] The lathe processing method is to fix the parts on the fixtures at both ends, drive them to rotate by the servo motor, and at the same time, the lead screw drives the turning tool to move horizontally to cut the workpiece, such as Figure 5 As shown in the figure, there are two major problems in lathe processing of slender rod parts: First, during the processing, the part will swing (radial deflection, the same below) in the middle of the high-speed rotation, and this swing phenomenon will cause the contact point of the turning tool to jump; second, during the turning process, the turning tool contacts the part to generate radial top force. When turning to the middle part of the part, the part will produce a large elastic deformation, affecting the cutting feed amount; the occurrence of the above two situations will naturally affect the processing quality and processing accuracy; the reasons for the occurrence of the problem: first, it is determined by the characteristics of the part. The part has a small diameter and a long length, which is easy to deform elastically; second, it is determined by the lathe processing method. Before turning, the part is first clamped and fixed with the lathe center, and then When the lathe is started, the part will rotate at high speed, and the turning tool will cut according to the instructions. During the tightening process of the slender rod-shaped part, a slight elastic deformation will occur, while the two ends of the part are fixed and the middle is suspended. When the part starts to rotate at high speed with the lathe, the middle part will inevitably produce a certain degree of rotational swing that deviates from the axial direction. This swing directly affects the contact and feed amount between the turning tool and the part. If the swing amplitude of the cutting point is too large, the contact between the turning tool and the part is almost non-existent, or even impossible. Even if there is contact, the radial top force of the turning tool contact and cutting process will increase the rotational swing of the part, causing the turning tool cutting point to jump or cutting to be discontinuous; and, if non-circular variable-section workpieces are processed, the lathe follower cannot be used.

[0005] The purpose of the present invention is to create another way and method for processing parts under the premise of ensuring the accuracy of parts and the processing qualification rate, so as to avoid the two major problems that occur when turning long and thin rod parts. Summary of the invention

[0006] The purpose of the present invention is to provide a high-precision variable-section long slender rod parts processing device and processing method, which can process high-precision slender rod variable-section parts with high quality through a grinding processing method of radial chord cutting and axial quadratic curve segment-by-segment approximation. After practical application, it is very suitable for the processing of high-precision slender rod variable-section parts, and the processing accuracy can reach 3‰.

[0007] The technical solution adopted by the present invention is as follows: a high-precision variable-section long and thin rod parts processing device, including a dividing plate, a main shaft, a tail center, a chuck, and a worktable, wherein a tail center is provided at one end of the worktable and a dividing plate is provided at the other end corresponding to the tail center. A chuck is provided on the side of the dividing plate corresponding to the tail center, and a dividing servo motor for driving the chuck to rotate is provided at the other end. The feature is that a main shaft connected to a CNC milling machine is also provided on the worktable, and a grinding wheel is provided on the main shaft.

[0008] The working principle of the present invention is as follows: Hardware transformation: replace the milling cutter on the original milling machine with a grinding wheel, fix the grinding wheel to the front end of the milling cutter, and change the milling of the milling cutter to grinding with a grinding wheel; second, the setting of the sand grinding arc angle, change the setting of the milling feed amount and the lateral movement of the milling cutter to the setting of parameters such as the sand grinding arc angle and the quadratic fitting curve, and change the sand milling and grinding technology to grinding. The basis of the technology of the present invention is to utilize the characteristics of the milling machine processing parts to remain stationary and the milling cutter to mill the surface of the parts, and change the milling to chord cutting grinding wheel grinding through the spindle tool head transformation; select a 4-axis CNC milling machine as the processing equipment, such as Figure 1 As shown, the milling cutter at the front end of the spindle is replaced with a grinding wheel, and the Y-direction (axial), X-direction (radial) and A-direction (circumferential) parameters of the workpiece are respectively injected through the CNC operating table to automatically complete the processing of high-precision slender rod variable-section parts.

[0009] Optionally, a grinding wheel rod is provided on the main shaft, a grinding wheel is mounted on the grinding wheel rod, and the grinding wheel is fixed to the grinding wheel rod by a gasket and a nut. The grinding wheel is detachably mounted for easy replacement.

[0010] A high-precision variable-section long thin rod part processing method, using the processing device of the present invention, is characterized by comprising the following steps:

[0011] S1. Select the workpiece, and calculate the radial grinding amount based on the actual size and drawing of the workpiece by formula (1), and calculate the arc angle by formula (2):

[0012] Δx=x0-x (1)

[0013]

[0014] In formula (1) and (2), x0 is the cross-sectional radius of the workpiece before grinding, x is the cross-sectional radius of the workpiece after grinding, and θ is the indexing rotation angle selected for each Y-direction grinding of the workpiece in the A direction;

[0015] According to the length and shape of the workpiece, a segmented quadratic fitting curve is used to approximate the variable speed motion. The number of segments is not less than the number of segments in the drawing. The shape definition of each segment should satisfy the quadratic function formula (3):

[0016] Y N =a0+a1·x+a2·x 2 (y∈ΔY N ΔY N =Y N -Y N-1 N=1,2,…) (3)

[0017] In formula (3), a0, a1, a2 are the initial value and weighting coefficient respectively. a0, a1, a2 must be obtained before the parameters are injected into the CNC milling machine. The calculation of a0, a1, a2 can be based on the workpiece radius, length value and intermediate interpolation value corresponding to the end point of each curve of the workpiece: (x n ,y n )、(x n+1 ,y n+1 ) and (x nc ,y nc ), and then substitute it into (3) to obtain:

[0018] a0=y N -a1x N -a2x N 2 (4)

[0019]

[0020]

[0021] make but

[0022] a1=-k 1n *k 4n +k 3n *k 5n (7)

[0023] a1=k 2n *(k 1n -k 3n ) (8)

[0024] To facilitate value retrieval, let

[0025] y nc =(y n +y n+1) / 2 (9)

[0026] Then according to the corresponding y in the figure nc Measured x nc ;

[0027] Once the workpiece is selected, the corresponding processing parameters and functions are obtained according to the above formulas (1) to (9); and the processing parameters and functions of the workpiece are programmed into the control console of the CNC milling machine or CNC machining center;

[0028] S2. Fix the workpiece on the CNC milling machine, install the workpiece on the chuck and clamp it with the tail center, then press the start button, and the milling machine will grind the workpiece with a tangential grinding wheel according to the injected program.

[0029] Optionally, the chord-cut grinding wheel performs chord-cut grinding at least twice, and the workpiece is rotated by a dividing servo motor to continuously select and adjust a suitable chord-cut grinding angle.

[0030] Optionally, the quadratic fitting curve fitting approximation is in the processing of the selected high-precision slender rod variable-section part, under the premise of a given grinding amount and indexing angle, each axial movement of the workpiece is CNC ground according to a similar or close part demand curve or theoretical curve.

[0031] Optionally, after the processing step S2, a belt cutting and grinding process is adopted.

[0032] Optionally, when the machining allowance of the workpiece blank is large, turning, heat treatment and grinding processes are used before the machining step S2.

[0033] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0034] The present invention transforms the milling cutter of the existing CNC milling machine, fixes the grinding wheel to the front end of the milling cutter, changes the milling of the milling cutter into grinding of the grinding wheel, and ensures the processing accuracy, and the transformation cost is low;

[0035] The present invention changes the settings of the milling cutter's milling feed amount and lateral movement into the settings of parameters such as the sanding arc angle and the quadratic fitting curve; the sanding milling and grinding technology changes turning and milling into grinding, and the milling processing point and direction can be flexibly selected according to the installation restrictions and movement modes of the milling head fixture of the milling machine. The grinding point can be selected from one of the top, bottom, and front sides, and the processing direction can move from left to right (or from right to left) in sequence. It is suitable for general milling machines and CNC milling machines. The use of a four-axis or more CNC milling machine has higher processing efficiency and more guaranteed processing accuracy.

[0036] The present invention not only overcomes the deflection and swing defects caused by the rotation of the workpiece during lathe processing without changing the working principle and processing method of the milling machine, but also avoids the problem that conventional CNC machine tools with high hardness and small margins cannot process or guarantee the accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0038] Figure 1 It is a schematic diagram of the chord milling and grinding process of slender rod parts on a 4-axis CNC milling machine;

[0039] Figure 2 It is a schematic diagram of the radial machining section of the workpiece;

[0040] Figure 3 It is a schematic diagram of the curve of the axial outer surface of the workpiece;

[0041] Figure 4 It is a schematic diagram of chordal grinding with a grinding wheel;

[0042] Figure 5 It is a schematic diagram of lathe processing in the prior art;

[0043] Markings in the figure are: 1-indexing plate, 2-spindle, 3-tail center, 4-workpiece, 5-chuck, 6-workbench, 7-grinding wheel rod, 8-grinding wheel, 9-gasket, 10-nut, 11-indexing servo motor. DETAILED DESCRIPTION

[0044] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] like Figure 1-4 As shown, a high-precision variable-section long thin rod part processing device includes a dividing plate 1, a main spindle 2, a tail center 3, a chuck 5, and a workbench 6. The workbench 6 is provided with a tail center 3 at one end, and a dividing plate 1 is provided at the other end. The dividing plate 1 is provided with a chuck 5 on the side corresponding to the tail center 3, and a dividing servo motor 11 for driving the chuck 5 to rotate is provided at the other end. It is characterized in that the workbench 6 is also provided with a main spindle 2 connected to a CNC milling machine, and a grinding wheel 8 is provided on the main spindle 2.

[0046] The working principle of the present invention is as follows: Hardware transformation: replace the milling cutter on the original milling machine with a grinding wheel 8, fix the grinding wheel 8 to the front end of the milling cutter, and change the milling of the milling cutter to grinding with the grinding wheel 8; second, the setting of the sand grinding arc angle, change the setting of the milling feed amount and the lateral movement of the milling cutter to the setting of parameters such as the sand grinding arc angle and the quadratic fitting curve, and change the sand milling and grinding technology to grinding. The basis of the technology of the present invention is to utilize the characteristics of the milling machine processing parts to remain stationary and the milling cutter to mill the surface of the parts, and change the milling to chord cutting grinding wheel grinding through the transformation of the spindle 2 cutter head; select a 4-axis CNC milling machine as the processing equipment, such as Figure 1 As shown, the milling cutter at the front end of the spindle 2 is replaced with a grinding wheel 8, and the parameters of the workpiece in the Y direction (axial direction), X direction (radial direction) and A direction (circumferential direction) are respectively injected through the CNC operating table to automatically complete the processing of high-precision slender rod variable cross-section parts; the present invention uses the ancient "cutting square to circle" and modern differential chord cutting theory, utilizes the one-to-one correspondence between circles, arcs, chords and angles, as well as the processing characteristics of turning, milling and grinding and the inherent characteristics of high-precision slender parts, explores and innovates a special processing technology, with the help of "cutting square to circle" and differential chord cutting theory, according to the processing characteristics of turning, milling and grinding and the characteristics of long and thin rod parts, explores and innovates sand milling and grinding technology, which is very suitable for the processing of conical variable cross-section long and thin rod parts, with high actual application efficiency and a qualified rate of 100%.

[0047] The main shaft 2 is provided with a grinding wheel rod 7, on which a grinding wheel 8 is mounted. The grinding wheel 8 is fixed to the grinding wheel rod 7 by a gasket 9 and a nut 10. The grinding wheel 8 is detachably mounted for easy replacement.

[0048] A high-precision variable-section long thin rod part processing method, using the processing device of the present invention, is characterized by comprising the following steps:

[0049] S1. Select the workpiece, and calculate the radial grinding amount based on the actual size and drawing of the workpiece by formula (1), and calculate the arc angle by formula (2):

[0050] Δx=x0-x (1)

[0051]

[0052] In formula (1) and (2), x0 is the cross-sectional radius of the workpiece before grinding, x is the cross-sectional radius of the workpiece after grinding, and θ is the indexing rotation angle selected for each Y-direction grinding of the workpiece in the A direction;

[0053] According to the length and shape of the workpiece, a segmented quadratic fitting curve is used to approximate the variable speed motion. The number of segments is not less than the number of segments in the drawing. The shape definition of each segment should satisfy the quadratic function formula (3):

[0054] Y N =a0+a1·x+a2·x 2 (y∈ΔYN ΔY N =Y N -Y N-1 N=1,2,…) (3)

[0055] In formula (3), a0, a1, a2 are the initial value and weighting coefficient respectively. a0, a1, a2 must be obtained before the parameters are injected into the CNC milling machine. The calculation of a0, a1, a2 can be based on the workpiece radius, length value and intermediate interpolation value corresponding to the end point of each curve of the workpiece: (x n ,y n )、(x n+1 ,y n+1 ) and (x nc ,y nc ), and then substitute it into (3) to obtain:

[0056] a0=y N -a1x N -a2x N 2 (4)

[0057]

[0058]

[0059] make but

[0060] a1=-k 1n *k 4n +k 3n *k 5n (7)

[0061] a1=k 2n *(k 1n -k 3n ) (8)

[0062] To facilitate value retrieval, let

[0063] y nc =(y n +y n+1 ) / 2 (9)

[0064] Then according to the corresponding y in the figure nc Measured x nc ;

[0065] Once the workpiece is selected, the corresponding processing parameters and functions are obtained according to the above formulas (1) to (9); and the processing parameters and functions of the workpiece are programmed into the control console of the CNC milling machine or CNC machining center;

[0066] S2. Fix the workpiece on the CNC milling machine, install the workpiece on the chuck and clamp it with the tail center, then press the start button, and the milling machine will grind the workpiece with a tangential grinding wheel according to the injected program.

[0067] The specific implementation is as follows:

[0068] Example 1

[0069] A high-precision variable-section long thin rod part processing method, using the processing device of the present invention, is characterized by comprising the following steps:

[0070] S1. Select the workpiece, and calculate the radial grinding amount based on the actual size and drawing of the workpiece by formula (1), and calculate the arc angle by formula (2):

[0071] Δx=x0-x (1)

[0072]

[0073] In formula (1) and (2), if Figure 2 As shown, OQ is the radius x0 of the cross section of the workpiece before grinding, the solid circle is the cross section of the workpiece after grinding, OS is the radius x of the cross section of the workpiece after grinding, and ∠POQ is the indexing rotation angle θ selected for each Y-direction grinding of the workpiece in the A-direction;

[0074] like Figure 3 As shown, according to the length and shape of the workpiece, a segmented quadratic fitting curve is used to approximate the variable speed motion. The number of segments is not less than the number of segments in the drawing. The shape definition of each segment should satisfy the quadratic function formula (3):

[0075] Y N =a0+a1·x+a2·x 2 (y∈ΔY N ΔY N =Y N -Y N-1 N=1,2,…) (3)

[0076] In formula (3), a0, a1, a2 are the initial value and weighting coefficient respectively. a0, a1, a2 must be obtained before the parameters are injected into the CNC milling machine. The calculation of a0, a1, a2 can be based on the workpiece radius, length value and intermediate interpolation value corresponding to the end point of each curve of the workpiece: (x n ,y n )、(x n+1 ,y n+1 ) and (x nc ,y nc ), and then substitute it into (3) to obtain:

[0077] a0=y N -a1x N -a2xN 2 (4)

[0078]

[0079]

[0080] make but

[0081] a1=-k 1n *k 4n +k 3n *k 5n (7)

[0082] a1=k 2n *(k 1n -k 3n ) (8)

[0083] To facilitate value retrieval, let

[0084] y nc =(y n +y n+1 ) / 2 (9)

[0085] Then according to the corresponding y in the figure nc Measured x nc ;

[0086] Once the workpiece is selected, the corresponding processing parameters and functions are obtained according to the above formulas (1) to (9); and the processing parameters and functions of the workpiece are programmed into the control console of the CNC milling machine or CNC machining center;

[0087] For ease of understanding, a variable diameter slender rod workpiece with a diameter of D = 13.720 ~ 7.235, L = 430 is selected as an example, the machining allowance is 0.1, the initial first grinding amount Δx is 0.05, and according to formula (2), the initial grinding angle θ will change from 13.835 to 19.051. According to the segmented values ​​given in the drawing, the coefficients a0, a1, and a2 of each segment of the quadratic fitting curve are determined. See Appendix 1 for details; in Appendix 1, x1, x3, y1, and y3 are the given values ​​of each segment interface drawing, x2 and y2 are the interpolation values ​​of each segment, y2 is determined by referring to formula (9), and x2 is measured on the drawing according to the corresponding value of y2;

[0088] When the grinding angle θ, grinding amount Δx, and coefficients a0, a1, and a2 of each quadratic fitting curve are determined, the relevant parameters and functions can be programmed and written in advance on the CNC milling machine (or CNC machining center, the same below) console;

[0089] S2. Fix the workpiece on the CNC milling machine, install the workpiece on the chuck and clamp it with the tail center, press the start button, and the milling machine will grind the workpiece with a tangential grinding wheel according to the injected program; this process is similar to milling, and the workpiece remains stationary during the processing. The difference is that the spindle milling head is transformed into a grinding wheel grinding head, and milling is changed to grinding with a grinding wheel;

[0090] Subsequent secondary grinding, tertiary grinding, ..., the parameters and coefficients related to the quadratic fitting function are obtained, and the CNC milling machine parameters and functions are injected, all in the same grinding. All measurement and calculation preparation work is completed before the workpiece is put on the bed. After each grinding is completed, only the corresponding control parameters and functions of the CNC milling machine parameters need to be changed to proceed to the next grinding until the determined accuracy is achieved.

[0091] The present invention not only overcomes the deflection and swing defects caused by the rotation of the workpiece during lathe processing without changing the working principle and processing method of the milling machine, but also avoids the problem that conventional CNC machine tools with high hardness and small margins cannot process or guarantee the accuracy.

[0092] According to geometry, there is a one-to-one correspondence between a circle, a chord, and an arc. From a chord, you can get an arc, or from a chord, you can get a circle. From a circle, you can get an arc or a chord. Figure 4 As shown, sand milling changes circular cutting into chord cutting grinding. As long as the appropriate chord grinding angle is continuously selected and adjusted according to the processing size and precision requirements of the parts, the expected accuracy can be achieved. Theoretically, the chord cutting chord cutting arc angle or chord diameter is gradually subdivided and reduced, infinitely approaching, and finally the ideal circle can be obtained.

[0093] Quadratic fitting approximation is an effective means to solve the problem of machining workpieces with complex shapes. It is widely used in the field of aerospace. In the machining of high-precision slender rod variable cross-section parts, as long as the segment selection is reasonable, or the segment differentiation is refined, the quadratic fitting approximation will gradually approach the required shape of the workpiece; according to the technology of the present invention, in the machining of selected high-precision slender rod variable circular cross-section parts, under the premise of a given grinding amount and indexing angle, as long as each axial movement of the workpiece is similar or close to the part demand curve (or theoretical curve), CNC grinding can achieve the required machining of high-precision slender rod variable circular cross-section parts.

[0094] Theoretically, the workpiece after chordal grinding with a grinding wheel is actually a part with a variable polygonal cross-section that is very close to the theoretical curve. In order to further realize the required variable circular cross-section parts, the technology of the present invention finally adds a sanding belt cutting and grinding process to make the entire technology more complete and practical.

[0095] The grinding wheel tangential grinding technology is a processing technology invented specifically for small-allowance, high-precision, slender rod variable-section parts. In the actual processing process, if the workpiece blank has a large processing allowance, in order to improve the processing efficiency, while ensuring the safety allowance, it can be turned, heat treated, and ground first according to the characteristics of the workpiece material, and then the grinding wheel tangential grinding can be performed.

[0096] The research group once modified a general four-axis CNC milling machine to process high-precision slender rod parts with a circular cross-section. They used the invented grinding wheel chord cutting grinding technology and conducted a comparative test with conventional turning. They processed a batch of precision slender rod parts with a circular cross-section ranging from the thinnest rod diameter of 4.2mm and a length greater than 500mm to a rod diameter of 20mm and a length greater than 800mm. The four-axis CNC milling machine's grinding wheel chord cutting grinding has high efficiency and a 100% part qualification rate. However, the same parts are time-consuming and labor-intensive to process by turning. For thick rods (rod diameter greater than 10mm), the accuracy can still be guaranteed, but as the rod diameter becomes thinner, the part processing qualification rate drops rapidly.

[0097] Sand milling and grinding processing technology utilizes the one-to-one correspondence between circles, arcs, chords and angles. It is a new processing technology that is explored and invented based on the ancient "cutting square to become circle", modern differential chord cutting theory and curve fitting theory, as well as the characteristics of turning, milling and grinding and the inherent characteristics of high-precision slender parts.

[0098] With the in-depth development of Industry 4.0, the need for long-distance fine control, manipulation, and transmission in smart and intelligent equipment or systems, and the demand for high-precision slender and rounded cross-section parts will increase. Therefore, the invention and innovation of this technology is of great significance and has broad application prospects.

[0099] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. The patent protection scope of the present invention shall be based on the claims. All equivalent structural changes made using the contents of the description and drawings of the present invention should also be included in the protection scope of the present invention.

[0100] Schedule 1

[0101] D: 13.72~7.236 L: 430 Reduced diameter parts processing parameter table

[0102]

[0103]

Claims

1. A high-precision variable-section long thin rod part processing method, characterized in that: A high-precision variable-section long thin rod part processing device is used for processing. The high-precision variable-section long thin rod part processing device includes a dividing plate, a spindle, a tail center, a chuck, and a workbench. A tail center is provided at one end of the workbench, and a dividing plate is provided at the other end. A chuck is provided on the side of the dividing plate corresponding to the tail center, and a dividing servo motor for driving the chuck to rotate is provided on the other side of the dividing plate. A spindle connected to a CNC milling machine is also provided on the workbench, and a grinding wheel is provided on the spindle; The steps include: S1. Select the workpiece, and calculate the radial grinding amount based on the actual size and drawing of the workpiece by formula (1), and calculate the arc angle by formula (2): （1） （2） In formulas (1) and (2), x0 is the cross-sectional radius of the workpiece before grinding, x is the cross-sectional radius of the workpiece after grinding, and θ is the indexing rotation angle selected by the grinding wheel for each Y-direction movement of the workpiece in the radial direction; The workpiece shape is fitted by a segmented quadratic fitting curve. The number of segments is not less than the number of segments in the drawing. The shape definition of each segment should satisfy the quadratic function (3): （n=1，2，…）（3） In formula (3), a0, a1, a2 are the initial value and weighting coefficient respectively. a0, a1, a2 must be obtained before the parameters are input into the CNC milling machine. The calculation of a0, a1, a2 is based on the workpiece radius, length value and intermediate interpolation value corresponding to the end point of each curve of the workpiece: (x n ,y n )、(x n+1 ,y n+1 ) and (x nc ,y nc ), and then substitute it into (3) to obtain: （4） （5） （6） make , , , , ,but （7） （8） To facilitate value retrieval, let （9） Then according to the corresponding Measured ; Once the workpiece is selected, the corresponding processing parameters and functions are obtained according to the above formulas (1) to (9); and the processing parameters and functions of the workpiece are programmed into the CNC milling machine console; S2. Fix the workpiece on the CNC milling machine, install the workpiece on the chuck and clamp it with the tail center, then press the start button, and the CNC milling machine will grind the workpiece with a tangential grinding wheel according to the input program.

2. A high-precision variable-section long thin rod part processing method according to claim 1, characterized in that: When the machining allowance of the workpiece blank is large, turning, heat treatment and grinding processes are adopted before the machining step S2.

3. A high-precision variable-section long thin rod part processing method according to claim 1, characterized in that: The main shaft is provided with a grinding wheel rod, on which a grinding wheel is mounted, and the grinding wheel is fixed on the grinding wheel rod through a gasket and a nut.

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