JP6206921B2 - Spinning method - Google Patents

Description

  The present invention relates to a spinning processing method for performing processing by pressing a roll against a rotating metal tubular body to cause plastic deformation.

  Spinning is a processing method in which a plate-shaped or tubular metal workpiece is rotated by a motor and pressed while pressing a processing roller against the metal workpiece to perform a forming process. An apparatus for performing such forming processing includes a main shaft for rotating a metal workpiece around a rotation axis, and a plurality of devices that are movable so as to intersect the rotation axis and press the metal workpiece while driving a processing roller. And a linear motion mechanism. Here, when processing while rotating the metal workpiece, in general, in order to maintain a constant radial position perpendicular to the feed amount in the direction along the main axis of the processing roller, Only a metal product with an axially symmetric shape with a coaxial circle in the cross-sectional shape perpendicular to can be processed.

  On the other hand, a method is also proposed in which the center axis direction at the end of machining or at the end of machining has an angle with the rotation axis direction of the metal workpiece, that is, a spinning method in which the center axis of the metal product is curved or inclined. Has been.

  For example, Patent Document 1 discloses a method of performing spinning while controlling a contact angle at a contact point between a metal workpiece and a processing roller so as to intersect at a predetermined inclination angle with respect to a center line of a main shaft. The processing roller is moved forward or backward in the main axis direction and the radial direction in synchronization with the rotation angle of the metal workpiece so as to draw a closed track in a plane rotating with the metal workpiece. Is continuously changed corresponding to the target shape data. As a result, it is possible to form a metal product having a shape in which the central axis direction at the end of processing or at the end of the processing is inclined with respect to the rotation axis direction of the metal workpiece or the central axis direction is curved.

  Furthermore, a method of spinning a metal product having an irregular cross-sectional shape instead of a coaxial circle has been proposed. Here, as in the method of Patent Document 1, the molding process from one end of the metal product to the other end can be performed at a time through one pass path of the processing roller. Is likely to occur. Accordingly, it is also considered that the metal product is formed from one end to the other end through a plurality of passage paths of the processing roller including the reciprocating motion and gradually deformed.

  For example, in Patent Document 2, the processing roller is reciprocated from one end to the other end of the product while giving the position control of the processing roller so as to suppress the occurrence of breakage due to the change in thickness, and the cross section perpendicular to the main axis is circular. Disclosed is a spinning method with no irregular cross-sectional shape. Each of the blank shape data and product shape data is stored, and the transient path shape data of the reciprocating processing roller is calculated as a data format represented by a point coordinate sequence on a plane composed of interpolation coefficients in the radial direction and the principal axis direction. During machining, machining is performed by interpolating the radial displacement and spindle displacement of the processing roller based on the transient path shape data and the spindle rotation angle, corresponding to the product shape data and blank shape data. ing.

JP 2009-298877 A JP 2011-189401 A

  Many products are used that have an angle with the direction of the rotation axis of the workpiece during the processing or at the end of the processing and have an irregular cross-sectional shape. For example, products in which a tubular material having a curved tip is given a mouth shape is used for automobile parts such as automobile exhaust systems, aircraft parts, energy-related parts, and other various fields.

  The present invention has been made in view of the situation as described above. The object of the present invention is to give an angle to the rotation axis direction of the workpiece while giving an angle to the central axis direction during or at the end of machining, and an irregular shape. An object of the present invention is to provide a spinning method capable of processing even a product having a cross-sectional shape.

  A spinning method according to the present invention is a spinning method for pressing a processing roller against a metal workpiece attached to a main shaft to form a blank into a metal product having a central axis that is curved or inclined, and the metal workpiece and Based on a predetermined main axis direction displacement, radial direction displacement and main shaft rotation angle, the main shaft rotation of the processing roller is performed so as to draw a closed orbit in a virtual plane inclined with respect to the main shaft at the contact point with the processing roller. In the process of pressing against the metal workpiece while reciprocating in the direction and the radial direction along the main axis in synchronization with the angle, the blank cross-section closed track in the virtual plane aligned at a predetermined interval along the central axis of the blank, Correspondingly, a metal product cross-section closed track in a virtual plane aligned along the central axis of the metal product is set, and the front The main-axis direction displacement, the radial direction displacement, and the main-axis rotation angle are provided for each contact point sequence of the metal workpiece and the processing roller so as to give a forming process from the blank cross-section closed track to the corresponding metal product cross-section closed track. It is characterized by giving to.

  According to this invention, by synchronizing the processing roller with the main shaft rotation angle and reciprocating in the direction along the main shaft and in the radial direction, the central axis direction during processing or at the end of processing is the rotation axis direction of the metal workpiece. Spinning can be applied with a simple data design even for products that are angled and have an irregular cross-sectional shape.

  In the above-mentioned invention, the intermediate shape data of the processing roller that gives a forming process from the blank cross-section closed track to the corresponding metal product cross-section closed track is a point coordinate on the principal axis and radial planes using interpolation coefficients. For each row, the main shaft direction displacement and the radial direction displacement of the processing roller are calculated by interpolation with respect to the main shaft rotation angle, and the position of the metal workpiece is controlled by causing the processing roller to follow the intermediate shape data. May be a feature.

  According to this invention, for spinning processing by a plurality of passage paths of the processing roller, the processing can be easily performed without complicating and increasing the path shape data in the course of the path process, and the fracture due to the wall thickness change can be achieved. Can also be suppressed.

It is a figure which shows the apparatus using the spinning processing method by this invention. It is a figure which shows the spinning processing method by this invention. It is a figure which shows the shape and cross section of a product. It is a figure which shows the shape and cross section of a blank. It is a figure which shows the spinning processing method by this invention. It is a figure which shows 1 process of the spinning processing method by this invention. It is a figure which shows the other example of the spinning processing method by this invention. It is a perspective view which shows the example of a processed product with the spinning processing method by this invention. It is a figure which shows the processing path of the spinning processing method by this invention. It is a figure which shows 1 process of the spinning processing method by this invention. It is a figure which shows 1 process of the spinning processing method by this invention.

  A spinning method according to one embodiment of the present invention will be described in detail with reference to FIGS. First, a spinning processing apparatus will be described.

  As shown in FIG. 1, the spinning processing device 1 is a device that performs processing by pressing a processing roller 15 against a workpiece 10. The workpiece 10 is fixed to the main shaft 13 by a jig 12, and is rotated together with the main shaft 13 by a motor 14 having a rotation angle sensor 14a such as an encoder for detecting the main shaft rotation angle θ.

  The processing roller 15 is on a linear motion table 16 driven by an actuator such as a ball screw or a hydraulic cylinder, and can be moved forward and backward in the radial direction of the workpiece 10 (Y-axis direction in FIG. 1). The linear motion table 16 can be moved forward and backward by the linear motion table 17 in parallel with the main shaft 13 (in the X-axis direction in FIG. 1).

  Displacement sensors 16a and 17a such as encoders for detecting respective feed amounts are attached to the linear motion tables 16 and 17, and an output is sent to the control device 30 that controls the actuator. Position control is performed.

  The control device 30 as a computer receives data such as the rotation angle sensor 14a of the motor 14, the displacement sensor 16a of the linear motion table 16, the displacement sensor 17a of the linear motion table 17, and the control signal according to control software installed in advance. Is generated and transmitted, and the positions of the linear motion tables 16 and 17 are controlled.

  As shown in FIG. 2, the storage device 30 a of the control device 30 is provided with three storage areas 31, 32 and 33. Here, a case will be described in which the straight tube shape 10a, which is the initial blank shape of the workpiece 10, is finally processed into a curved tube shape 10b having a curved central axis (see FIG. 3).

  The first storage area 31 stores target shape data of the bent tube shape 10b that is a product. The target shape data includes X-axis displacement, Y-axis displacement, and spindle rotation angle for each contact point sequence on the surface of the processing roller 15 and the curved tube shape 10b in each of a plurality of cross sections having different inclination angles with respect to the spindle 13. It is stored in a data format with θ as a set. This will be described later.

  Similarly, the shape data of the straight pipe shape 10a is stored in the second storage area 32. The shape data is stored in a data format in which the X axis displacement, the Y axis displacement, and the main shaft rotation angle θ are set for each contact point sequence on the surface of the processing roller 15 and the straight pipe shape 10a. The third storage area 33 stores a transient path (intermediate path) of the processing roller 15 from the shape data of the straight tube shape 10a to the target shape data of the curved tube shape 10b step by step. ing. The transient shape data is stored as a point coordinate sequence on a plane composed of a plurality of interpolation coefficients in the X-axis direction and the Y-axis direction.

The calculation unit 30b of the control device 30 performs an interpolation calculation from the shape data stored in the storage areas 31, 32, and 33 of the storage device 30a and the main shaft rotation angle θ, and performs a target displacement (X _t , Y _t ) is calculated, and the linear motion tables 16 and 17 are servo-controlled via the servo control unit 30c to cause the processing roller 15 to follow the target displacement. Details will be described later.

  Next, the processing operation of the above-described spinning processing apparatus 1 will be described.

  In short, the spinning process reaches the target shape data of the curved tube shape 10b stored in the storage areas 31, 32 and 33, the shape data of the straight tube shape 10a which is a blank, and the final shape of the processing roller 15. From the transient path (intermediate path) and the main shaft rotation angle θ, the actual target displacement of the processing roller 15 is obtained by interpolation calculation, and the processing is performed by causing the processing roller 15 to follow the target displacement with the linear motion tables 16 and 17. Do it.

  As shown in FIG. 3, the target shape data of the curved tube shape 10b is the X axis and Y axis of the contact point sequence between the processing roller 15 and the curved tube shape 10b surface in a plurality of cross sections having different inclination angles with respect to the main shaft 13. It is expressed in the form of displacement and spindle rotation angle θ.

For example, a curved tube shape 10b, which is a curved tube shape as shown in FIG. 3A, has a plurality of cross sections D having different inclination angles with respect to the main axis direction S as shown in FIG. ₁ ... D _k−1 , D _k , D _{k + 1} ..., And intersecting lines d ₁ ... D _k−1 with the curved tube shape 10b in each cross section D ₁ ... D _k−1 , D _k , D _{k + 1} . d _k , d _{k + 1} ... are closed curves. Here, the k-th cross-sectional shape (closed curve) d _k is expressed by (X _p (k, θ), Y _p (k, θ)) with the main shaft rotation angle θ as an argument. That is, the rotation angle θ is changed in the curved pipe shape 10b, if the processing rollers 15 in the closed curve d _k is in contact with the k-th cross-sectional shape (closed curve) d _k of the curved pipe shape 10b, X-axis displacement of the machining roller 15 X _p (k, θ) and Y-axis displacement are represented by Y _p (k, θ). This is numerically calculated while gradually changing the inclination angles of the cross-sections D _1, D _k−1 , D _k , D _{k + 1} , and the corresponding closed curves d _k−1 , d _k , d _{k + 1} . This means that target shape data for forming the bending tube shape 10b can be obtained. These can be calculated from the design data of the target shape and the like according to the procedure described later.

Similarly, a straight pipe shape 10a having a shape as shown in FIG. 4A has a plurality of cross sections D ₁ ′... D _k−1 ′, D _k ′, D as shown in FIG. _When cut along _{k + 1} ′, the intersecting lines d ₁ ′, d _k−1 ′, d _k ′, and the straight pipe shape 10a in the respective cross sections D ₁ ′, D _k−1 ′, D _k ′, D _{k + 1} ′,. d _{k + 1} ′... are all closed curves having the same shape. That is, the k-th cross-sectional shape (closed curve) d _k is represented by (X _b (k, θ), Y _b (k, θ)) with the main shaft rotation angle θ as an argument. Here, when the straight pipe shape 10a is a circular pipe, the Y-axis displacement Y _b (k, θ) is a constant value.

The target shape data (X _p (k, θ), Y _p (k, θ)) of the curved tube shape 10b is stored in the first storage area 31 in the shape data (X _b (k, θ), Y _b (k, θ)) is stored in the second storage area 32, respectively.

  Here, as shown in FIG. 5, the control device 30 controls the displacement in the X-axis direction and the displacement in the Y-axis direction of the processing roller 15 so as to synchronize with the rotation angle θ of the workpiece 10. The trajectory of the 15 contact points draws a closed trajectory in a plane orthogonal to the curved central axis CL.

  Here, a calculation method of the feed displacement in the main shaft direction and the feed displacement in the radial direction of the processing roller 15 will be described as a circle C having a radius R as a closed curve of the target shape data with reference to FIG.

The distance from the intersection Q of the plane c including the circle C and the main axis center line S to the center of the circle C is defined as d. Further, it is assumed that the plane c including the circle C and the main axis center line S intersect at an angle α. The distance r from the point Q to the point P on the circle C is expressed by the following (Expression 1) using the angle φ.

On the other hand, (Formula 2) is established between the rotation angle θ and the angle φ of the workpiece 10.

Further, when the feed displacement y in the radial direction of the processing roller 15 is expressed as a distance from the contact point P between the processing roller 15 and the workpiece 10 to the spindle center line S, (Expression 3) is established.

Additionally, expressed with reference to the position x _Q of the main axis of the feed displacement x of the point Q of the processing rollers 15, holds the equation (4).

  As the calculation procedure, the angle φ is obtained from the rotation angle θ of the workpiece 10 by (Equation 2), then the distance r is obtained from (Equation 1), and finally the feed displacement from (Equation 3) and (Equation 4) ( X, Y) can be determined.

  Although the circular closed track C has been described here, the shape of the closed track C can be freely determined. For example, a closed orbit C ′ having an irregular shape as shown in FIG. 7 may be used. The distance r from the intersection point Q ′ of the plane c ′ including the closed trajectory C ′ and the center axis S of the main axis S to the point P ′ on the closed trajectory C ′ is expressed as a function r = r (φ) of the angle φ. If used instead of 1), the feed displacement X in the main axis direction and the feed displacement Y in the radial direction of the processing roller 15 can be calculated.

  Further, if a polygon or an ellipse is given as the shape of the closed orbit, the cross section of the product also becomes a polygon or an ellipse, respectively, so that it has an irregular cross-sectional shape as shown in FIGS. Shapes with curved S can also be formed.

  Next, generation of shape data in a transient route will be described.

As shown in FIG. 9, the shape data in the transitional path of the processing roller 15 from the straight tube shape 10 a stored in the third storage area 33 to the curved tube shape 10 b in stages is from 0 to 1. It is expressed as a point coordinate sequence on a normalized plane consisting of up to interpolation coefficients. Here, S _xt represents the straight tube shape 10a and the curved tube shape 10b, and is an interpolation coefficient for determining one cross-sectional shape from each of a plurality of cross-sectional shape data arranged in the main axis direction. When S _xt = 0, a set of cross-sectional shapes on the most distal side (right end, see FIGS. 1 and 3) is selected, and when S _xt = 1, the most jig side (left end, see FIGS. 1 and 3) A set of cross-sectional shapes is selected.

On the other hand, S _yt is an interpolation coefficient for interpolating between the cross-sectional shapes of the straight tube shape 10a and the curved tube shape 10b determined by S _xt and calculating the actual principal axis direction and radial displacement of the processing roller 15. It is. S _yt = 0 is a state in which the processing roller 15 reaches the curved tube shape 10b, that is, the target shape data (X _p (k, It shows that it is equal to the value connecting θ) and Y _p (k, θ)). In addition, S _yt = 1 is a state in which the processing roller 15 is in contact with the surface of the straight pipe that is a blank, that is, the blank shape data (X _b (k, θ), Y _b (k, θ)) is equal to the value connecting.

  Here, in the curved tube shape 10b of FIG. 3, when forming the wall surface of the curved tube extending from the left end to the right, the stepwise forming process by the processing roller 15 will be described.

In the first processing, the processing roller 15 starts (S _xt , S _yt ) = (1, 1), that is, the surface on the jig 12 side of the straight pipe shape 10a, and gradually deepens the cut in the radial direction. While moving to the tip (S _xt = 0) of the workpiece, the first stage spinning process with a small deformation amount is performed.

Next, the processing roller 15 is reversed to the right side from the position corresponding to the workpiece tip toward the jig 12 side, and reaches the workpiece left end (S _xt = 1) while gradually deepening the radial cut. The second stage spinning process is performed.

As the number of times increases, the radial cut becomes deeper, and the straight pipe shape 10a approaches the curved pipe shape 10b, which is the target shape. In addition, since the displacement in the direction of the main shaft 13 also approaches the target shape data X _p (k, θ), the movement of the processing roller 15 is along a closed curve inclined with respect to the main shaft 13.

  Thereafter, similarly, in FIG. 9, the processing roller 15 reciprocates in three and a half times within the section from the left end to the right end of the workpiece 10, and gradually approaches the straight tube shape 10a as the blank to the curved tube shape 10b. While completing the spinning process.

During processing, the processing roller 15 moves back and forth in the main axis direction and the radial direction in synchronization with the rotation angle θ of the main shaft 13, but the transient path can be set as a curved line on the plane, and the back-and-forth movement synchronized with the rotation angle. Regardless, it can be done in the same way as the processing roller path in the axially symmetrical shape. As the path of the processing rollers 15, if you try to advance all set to radial displacement Y _t of processing rollers 15 corresponding to the rotation angle θ and the main axis direction displacement X _t of the main shaft 13, to set a very large 3D data However, the amount of data can be greatly suppressed by the interpolation calculation as described above.

In the interpolation calculation when a point (S _xt , S _yt ) on the transient path to the final shape of the processing roller 15 in the third storage area 33 and the spindle rotation angle θ are given, the processing roller 15 The calculation of the displacement in the main axis direction and the radial direction is as follows.

First, the cross-sectional shapes of the straight tube shape 10a and the curved tube shape 10b corresponding to this are determined one by one from S _xt . _Let EX _p (k) and EX _b (k) be the average values of the main shaft rotation angle θ of X _p (k, θ) and X _b (k, θ), respectively.
k = 1,. . . , N
EX _pt = {EX _p (n) −EX _p (1)} · S _Xt
EX _bt = {EX _b (n) −EX _b (1)} · S _Xt
And

Then, referring to the target shape data of the curved tube shape 10b in the first storage area 31, regarding the displacement in the main axis direction,
EX _p (k) <EX _pt <EX _p (k + 1)
K of the cross-sectional shape in which is established is obtained. Then
_{X p (X t, θ)} = {(EX pt -EX p (k)) · (X p (k + 1, θ) + (EX p (k + 1) -EX pt) · X p (k, θ)} / (EX _p (k + 1) −EX _p (k))
Y _p (X _t , θ) = {(EX _pt −EX _p (k)) · (Y _p (k + 1, θ) + (EX _p (k + 1) −EX _pt ) · Y _p (k, θ)} / (EX _p (k + 1) −EX _p (k))
Thus, a set of a principal axis direction displacement X _p (S _xt , θ) and a radial direction displacement Y _p (S _xt , θ) of the curved tube shape 10b corresponding to S _xt when the principal axis rotation angle is θ is obtained.

Similarly, with reference to the shape data of the blank straight tube shape 10a of the second storage area 32, regarding displacement in the main axis direction,
EX _b (k) <EX _bt <EX _b (k + 1)
K of the cross-sectional shape in which is established is obtained. Then
_{X b (X t, θ)} = {(EX bt -EX b (k)) · (X b (k + 1, θ) + (EX b (k + 1) -EX bt) · X b (k, θ)} / (E _Xb (k + 1) −E _Xb (k))
Y _b (X _t , θ) = {(EX _bt −EX _b (k)) · (Y _b (k + 1, θ) + (EX _b (k + 1) −EX _bt ) · Y _b (k, θ)} / (EX _b (k + 1) −EX _b (k))
_By, corresponding to the _{S xt,} principal axis direction displacement _X b _{(S xt, θ)} of the straight pipe shape 10a and radial displacement _Y b _{(S xt, θ)} set of sought.

Using the transient radial displacement S _yt of the processing roller 15, the shape data of the straight tube shape 10a and the curved tube shape 10b are interpolated. That means
_{X t = S yt · X b} (S xt, θ) + (1-S yt) · X p (S xt, θ)
_{Y t = S yt · Y b} (S xt, θ) + (1-S yt) · Y p (S xt, θ)
The main axis direction displacement _{X t} and radial displacement _{Y t} of the machining roller 15 is determined.

As shown in FIG. 10, this interpolation calculation is performed by first obtaining two cross-sectional shape data X _p (k, θ), Y _p (k, θ) and X _p (k + 1, θ), Y _{p of} the curved tube shape 10b. from (k + _1, θ), the cross-sectional shape data _X p corresponding to _{S xt (S xt, θ)} , Y p (S xt, θ) to the interpolation calculation. Further, the two cross-sectional shape data _X b of the curved pipe shape _{10b (k, θ), Y} b (k, θ) and _{X b (k + 1, θ} ), Y b (k + 1, θ) _from, corresponding to _{S xt} The cross-sectional shape data X _b (S _xt , θ) and Y _b (S _xt , θ) to be interpolated are calculated. In other words, the shape data of the straight pipe shape 10a and the curved pipe shape 10b are interpolated using the interpolation coefficient S _yt of the transient path data as a weighting coefficient, and the main shaft direction displacement X _t and the radial direction displacement Y _t of the processing roller 15 are interpolated. Calculate.

  The above interpolation calculation is realized by a program installed in the control device 30 of the spinning processing device 1.

  Here, the interpolation calculation will be described with reference to FIG.

Each closed curve 11, the main axis direction displacement X _t and radial displacement Y _t of processing rollers 15 are those expressed in relative orbital against blank. Regarding the interpolation coefficient S _yt in the cross section determined by the interpolation coefficient S _xt , when S _yt = 1, the trajectory of X _t and Y _t is the surface shape X _b (S _xt , θ), Y _b (S _xt , θ). When S _yt = 0, the trajectories of X _t and Y _t are _{equal to} the target cross-sectional shapes X _p (S _xt , θ) and Y _p (S _xt , θ) of the curved tube shape 10b. When 0 <S _yt <1, the trajectories of X _t and Y _t take an intermediate shape according to the value of S _yt .

That is, as shown in FIG. 3, when the value of S _yt gradually approaches 1 from 0, the workpiece 10 gradually approaches the target curved tube shape 10b from the blank straight tube shape 10a, and finally, In accordance with the curved tube shape 10b, the processing is completed.

  In the interpolation calculation, it is possible to easily calculate a plurality of reciprocations by only a transitional path to reach the final shape of the processing roller 15 represented by a curved line on the plane. It is possible to easily adjust the processing parameters and obtain the optimal processing conditions.

In order to perform molding with higher accuracy, it is preferable to set the target shape data X _p (S _xt , θ) and Y _p (S _xt , θ) with a finer mesh. In addition, depending on the material characteristics such as deformation followability to the stress of the blank, the thickness, further the amount of deformation required to reach the final shape, or the required processing quality, it is automatically obtained from a map obtained experimentally in advance. You may make it determine automatically.

  As described above, the workpiece 10 can be molded both in a tubular material or a plate-like material, and the shape of the closed track drawn by the contact point between the workpiece 10 and the processing roller 15 is an ellipse or a polygon. Any closed curve shape that is not circular may be used. In other words, the shape of the cross section is not limited to a circle, and even products having a deformed cross-sectional shape such as an ellipse or a polygon and having a curved central axis can be molded. Furthermore, by a plurality of paths of the processing roller 15, for example, even a product that cannot be processed by a single path of the processing roller 15, such as a mouth-opening shape of a tube having a curved tip, can be processed. Diversify products and expand applications.

  As mentioned above, although the Example by this invention and the modification based on this were demonstrated, this invention is not necessarily limited to this, A person skilled in the art will deviate from the main point of this invention, or the attached claim. Various alternative embodiments and modifications could be found without doing so.

DESCRIPTION OF SYMBOLS 1 Spinning processing apparatus 10 Work 10a Straight pipe shape 10b Curved pipe shape 12 Jig 13 Main shaft 14 Motor 15 Processing roller 14a Rotation angle sensor 16, 17 Linear motion table 16a, 17a Displacement sensor 30 Control device 30a Storage device 30b Calculation unit 30c Servo Control unit 31, 32, 33 Storage area

Claims (2)

A spinning method that presses a processing roller against a metal workpiece attached to a main shaft and forms a blank into a metal product having a curved or inclined central shaft,
Based on predetermined principal axis direction displacement, radial direction displacement, and main shaft rotation angle so as to draw a closed trajectory in a virtual plane inclined with respect to the main axis at the contact point between the metal workpiece and the processing roller, the processing In the process of pressing the roller against the metal workpiece while reciprocally moving the roller in a direction along the main axis and in a radial direction in synchronization with the main shaft rotation angle,
A blank cross-section closed track on a virtual plane aligned at a predetermined interval along the central axis of the blank, and a metal product cross-section closed track on a virtual plane aligned along the central axis of the metal product is set correspondingly. The main-axis direction displacement, the radial-direction displacement, and the main-axis rotation angle are in contact with the metal workpiece and the processing roller so as to give a forming process from the blank cross-section closed track to the corresponding metal product cross-section closed track. A spinning method characterized by being given for each point sequence. The intermediate shape data of the processing roller that gives a forming process from the blank cross-section closed track to the corresponding metal product cross-section closed track is processed for each point coordinate sequence on the principal axis direction and radial plane using an interpolation coefficient. The displacement of the main shaft direction and the radial direction displacement of a roller are interpolated and calculated with respect to the main shaft rotation angle, and the position of the metal workpiece is controlled by causing the processing roller to follow the intermediate shape data. Item 4. The spinning method according to Item 1.

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