JP2006340778A - Manufacturing method of golf club head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To highly precisely and simply perform positioning in machining a head and head machining. <P>SOLUTION: Three-dimensional coordinates of a specific point (p) of at least one point of the head 1a before the machining are measured and a rotation angle of the head is found based on the three-dimensional coordinates of the specific point (p) for making the head into a reference attitude. The head machining is performed based on machining data corresponding to the reference attitude. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a golf club head.

As a method for forming a golf club head, forging, casting, cutting (shaving), and the like are common. Among these, the lost wax precision casting method is generally used as casting, and as the cutting process, for example, a method using an NC controlled cutting machine is known.
In addition, the head formed by forging or the like is partially cut. Patent Document 1 is characterized in that, in an iron-type golf club head, a head body having a cavity formed on a back face is manufactured by forging, and then the cavity portion is additionally processed by cutting to form a deeper cavity. Manufacturing method is described (see Patent Document 1). Similarly, Patent Document 2 describes a method for manufacturing a golf iron club head in which a cavity portion of a back face of a head formed by forging or the like is cut with a cutting tool having a predetermined shape (Patent Document 2). reference.).
Japanese Patent Laid-Open No. 10-234897 JP-A-10-216277

  Particularly in recent years, the structure of golf club heads has become even more complex. For example, a head in which a plurality of members are joined has been developed for the purpose of increasing the degree of freedom in design such as the position of the center of gravity and improving the resilience performance. For example, a composite head in which titanium-based members are joined together by welding, or a metal member and a CFRP member are combined has been developed.

  Further, in recent years, the thickness of the head tends to be reduced with an increase in the size of the head, and the joint portion of the head is also reduced in thickness. Moreover, since the joint tends to become larger (or longer) with an increase in the size of the head and an increase in the degree of freedom in designing the head, an error in the joint is more likely to become apparent. Therefore, in order to suppress the dimensional deviation between the members of the head and ensure the joining, it is necessary to increase the dimensional accuracy between the members. For this reason, in order to suppress the dimensional error of the joint part of each head produced by casting etc., the technique which raises the dimensional accuracy of a joint part by cutting the said joint part partially by CNC processing etc. can be considered. .

  Even in a head having no joint, it is effective to cut the head by CNC machining or the like in order to increase the dimensional accuracy of the head. In this case, as compared with a head manufactured by casting, forging, or the like, effects such as a reduction in shape error between individual heads and an increase in the accuracy of the center of gravity of the head can be obtained.

  However, each golf club head, such as an iron head or a wood head, has a different shape for each type or count, and the head outer surface has many free-form surfaces. Therefore, it is difficult to accurately position the head when performing head processing. Therefore, even if a computer-controlled machining method such as CNC machining is used, since the head fixing position is unstable, high-precision machining cannot be performed. In addition, it was possible for a skilled worker to perform head positioning by performing subtle position adjustment using a head fixing jig, but in this case, time, labor, and more Requires the skill of the operator and a special jig for each head.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a golf club head manufacturing method capable of accurately and easily performing head positioning and head processing during head processing.

  The first invention in the present invention is a first step of fixing the pre-processing head positioned in a predetermined position in the axial direction of the shaft hole and being rotatable around the axis, and the pre-processing head fixed in the first step A second step of measuring the three-dimensional coordinates of at least one specific point above, and for arranging the specific point at a predetermined reference position based on the three-dimensional coordinates of the specific point measured in the second step A rotation angle of the head is obtained, and the pre-processing head is rotated around the axis by the rotation angle to make the pre-processing head a specific reference posture, and the reference posture is maintained while maintaining the reference posture. And a fourth step of processing the pre-processing head by corresponding processing data.

  In the above manufacturing method, the degree of freedom in changing the position and posture of the head is regulated by fixing in the first step, except for rotation around the axis of the shaft hole. Therefore, if the head is rotated around the axis of the shaft hole so that a specific point set on the head is arranged at a predetermined reference position while maintaining this restricted state, the posture and position of the head are uniquely determined. Then, the head is positioned in the reference posture. Since the rotation angle of the head for locating the specific point at a predetermined reference position is obtained based on the three-dimensional coordinates of the specific point, the alignment of the head rotation is performed with extremely high accuracy, and a positioning jig Etc. need not be used. Since the head is processed based on the processing data corresponding to the reference posture, the head in the reference posture can be processed with high accuracy. The fixing in the first step can be easily performed by using a shaft hole or a hosel portion of the head.

  In the above manufacturing method, the protrusion for the specific point is provided on the head before processing, the specific point is set on the protrusion, and the protrusion is cut when the head is processed in the reference posture. It is good also as a structure to perform. By providing the protrusion for the specific point, the position of the specific point becomes clearer and the accuracy of the three-dimensional measurement of the specific point can be improved. In addition, by cutting the protrusions during head processing, the work of cutting the protrusions is not necessary, so the productivity of the head is improved. Further, since the protrusion is finally cut off, the protrusion does not affect the hitting performance of the head. Therefore, the protrusion can be provided without being restricted by its position and shape.

  Further, the second invention in the present invention is a first step of fixing the pre-processing head in a state in which the shaft hole is positioned at a predetermined position in the axial direction of the shaft hole and is rotatable around the axis, and the first step is fixed in the first step. A second step of photographing a two-dimensional image from at least one direction in the pre-processing head, a plurality of head contour shapes obtained based on three-dimensional data of the pre-processing head prepared in advance, and a head contour obtained from the two-dimensional image A third step of obtaining a rotation angle of the head for obtaining a specific reference posture by comparison with the shape, and setting the pre-processing head to the reference posture by rotating the pre-processing head around the axis by this rotation angle. And a fourth step of processing the pre-processing head with processing data corresponding to the reference posture while maintaining the reference posture. It is a method of manufacturing a full club head.

  In the manufacturing method of the second invention, the first step and the fourth step are the same as the first invention, but the second step and the third step are different from the first invention. That is, in the first invention, the rotation angle for setting the head to the reference posture is obtained based on the three-dimensional coordinates of the specific point, but in the second invention, the head is set to the reference posture based on the contour shape of the head. The rotation angle to find out. That is, since a golf club head is an indefinite shape having a free curved surface or the like unlike a sphere or the like, the contour shape of the head varies depending on the position of the viewpoint, and the posture of the head can be specified by specifying this contour shape. it can. Therefore, the rotation angle for setting the head to the reference posture can be obtained from the contour shape of the head. In the third step, the rotation angle of the head is obtained by comparing a plurality of head contour shapes obtained based on three-dimensional data of a pre-processed head prepared in advance and a head contour shape obtained from the two-dimensional image. Therefore, the alignment of the rotation of the head can be performed with extremely high accuracy, and it is not necessary to use an alignment jig or the like. In addition, the effect of a 1st process and a 4th process is the same as said 1st invention.

  In each of the above inventions, it is preferable that the golf club head has a joint portion formed by joining a plurality of members and positioned on a curved surface portion of the head, and the processing of the head includes processing of the joint portion. In the joint portion located at the curved surface portion, the curved surface portions of the members to be joined are joined together, so that dimensional accuracy between the members is particularly required. Therefore, the said effect in this invention increases further by applying this invention to the process of the junction part located in a curved-surface part.

  In each of the above inventions, the golf club head is preferably a hollow wood type golf club head. Since the hollow structure head is relatively thin, high machining accuracy is required. However, particularly in the case of a wood type golf club head, most of the outer surface thereof is constituted by a curved surface, and accurate positioning becomes even more difficult as compared with an iron head having a flat face surface. Therefore, by applying the present invention to a hollow wood type golf club head, the effect of the present invention for improving the positioning accuracy of the head is more effectively exhibited.

  Since the head is positioned by calculation based on the three-dimensional data and the two-dimensional image, the head can be accurately positioned without depending on the positioning jig, the skill of the worker, or the like. Therefore, head processing can be performed with high accuracy.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a perspective view showing a state in which a golf club head manufacturing method according to an embodiment of the present invention is carried out.
A golf club head (hereinafter also simply referred to as a head) manufactured by the manufacturing method of this embodiment is a so-called wood-type hollow golf club head. The finished golf club head (not shown) is a head in which another member such as CFRP or a different metal is joined to the opening (finishing opening k2 described later) of the crown.

  FIG. 4 is a plan view of the pre-processing head 1a having the initial opening k1 in the crown portion as seen from the crown portion side. This pre-processing head 1a includes a face portion 2 having a face surface that is a surface that comes into contact with a ball at the time of hitting as an outer surface, a crown portion 3 constituting an upper surface of the head, a sole portion 4 constituting a lower surface of the head, and a face A portion other than the portion 2 has a side portion 5 extending between the crown portion 3 and the sole portion 4 and a shaft hole 6 which is a hole for inserting and bonding a golf club shaft (not shown). However, as shown in FIG. 4, an initial opening k1 as a through-hole is provided at a substantially central portion of the crown portion 3, and in the pre-processing head 1a, the inside of the head is visible from the initial opening k1. (In FIG. 4, the inner surface of the sole portion 4 is visible from the initial opening k1). In FIG. 4 and FIG. 5 to be described later, the description of the concavo-convex lines visually observed on the inner surface of the head is omitted.

  In the pre-processing head 1a, a portion having an initial opening k1 (in this embodiment, the crown portion 3) is manufactured by casting. By forming the crown portion 3 by casting, the initial opening k1 can be easily formed. Moreover, parts other than the crown part 3 are manufactured by forging, pressing, or casting. Note that the pre-processing head 1a may be manufactured integrally by casting, or may be manufactured by joining a plurality of members by welding or the like.

  In this manufacturing process, by cutting the peripheral edge of the initial opening k1 by CNC machining, the initial opening k1 is enlarged to form a finished opening k2 (see FIG. 5). Become. In FIG. 5, the portion removed by the cutting process is indicated by two-dot chain line hatching. With this cutting process, the opening edge of the crown opening is CNC machined over the entire circumference. Then, a separate crown (not shown) as a separate member having the same contour shape as the finish opening k2 is joined to the head 1b (crown portion 3) after processing to close the finish opening k2, thereby completing the finished product. A head is manufactured. In addition, as the material of the separate crown, a material different from the material of the crown portion 3 in the post-processing head 1b is used. For example, CFRP (carbon fiber reinforced plastic), titanium alloy, pure titanium, magnesium alloy, aluminum alloy, Etc. may be adopted.

  Since the initial opening k1 is formed by casting, deformation occurs in the process of being cooled and solidified after being poured into the mold. Due to this deformation, the shape of the initial opening k1 varies greatly. However, in the present embodiment, the entire periphery of the opening edge of the initial opening k1 is accurately CNC processed to form the finishing opening k2, so that the dimensional error of the crown opening (finishing opening k2) is extremely high. It has been reduced.

Hereinafter, the process of cutting the opening edge of the initial opening k1 will be described in detail.
In this step, a head rotating machine 10 that can rotate the head around the axis line z of the shaft hole and a three-dimensional measuring device 20 are used.
FIG. 1 is a perspective view showing the state of the process of this embodiment, and FIG. 2 is an enlarged view in the vicinity of the head. As shown in FIG. 1, the head rotating machine 10 includes a rotary table 11 that rotates about a predetermined rotation axis r, and a base portion 12 that rotatably supports the rotary table 11. The turntable 11 has a cylindrical shaft hole insertion portion 13 (shown by a broken line in FIG. 2) having an outer diameter substantially the same as the inner diameter of the shaft hole 6 of the head 1a before processing. The shaft hole insertion portion 13 rotates integrally with the turntable 11. The center axis line of the shaft hole insertion portion 13 coincides with the rotation axis r of the turntable 11 described above.

  Further, the head rotating machine 10 includes a motor (not shown) such as a servo motor that can rotate the rotary table 11 by a desired angle, and a control unit 30 that is connected to the motor and controls the rotation angle of the rotary table 11. Have. The control unit 30 calculates a rotation angle of the turntable 11 and is connected to a computer 31 that transmits information about the rotation angle to the control unit 30.

  In the first step of this embodiment, the pre-processing head is fixed in a state where the shaft hole 6 is positioned at a predetermined position in the axis z direction and is rotatable around the axis z. For this purpose, first, the shaft hole insertion portion 13 is inserted into the shaft hole 6 of the head 1a before processing. The outer diameter of the shaft hole insertion portion 13 is set to a value that hardly causes a gap with the inner surface of the shaft hole 6. Therefore, in the state in which the shaft hole insertion portion 13 is inserted into the shaft hole 6, the axis line z of the shaft hole of the pre-processing head 1 a substantially coincides with the center axis line of the shaft hole insertion portion 13. Further, as described above, the center axis of the shaft hole insertion portion 13 coincides with the rotation axis r of the turntable 11. Therefore, in a state where the shaft hole insertion portion 13 is inserted into the shaft hole 6, the rotation axis r of the turntable 11 and the axis line z of the shaft hole of the pre-processing head 1a are substantially aligned. Therefore, when the turntable 11 is rotated about the rotation axis r, the pre-processing head 1a rotates about the axis line z of the shaft hole.

The shaft hole insertion portion 13 may be a cylinder made of metal, resin, or the like. In this case, it is necessary to adjust the outer diameter of the shaft hole insertion portion 13 according to the inner diameter of the shaft hole 6. Therefore, as the shaft hole insertion portion 13, one having a chuck mechanism that is equally divided in the circumferential direction (for example, 2 to 4) and that expands in the radial direction while maintaining the central axis line may be employed. The chuck mechanism presses and fixes the shaft hole from the inside by, for example, hydraulic pressure or air pressure, and can fix the shaft hole 6 having various inner diameters without causing shaft shake.
Further, in this embodiment, the shaft hole insertion portion 13 is inserted into the shaft hole 6. However, particularly in a head or the like in which the outer peripheral surface of the neck portion is a circumferential surface, the outer diameter of the neck portion is substantially equal. An insertion hole having an inner diameter may be provided on the head rotating machine side, and the neck portion may be inserted into the insertion hole so that the rotation axis r and the axis line z of the shaft hole coincide with each other. Furthermore, in this case, the pre-processing head 1a is rotated while the axis line z and the rotation axis r are made coincident with each other by a fixture having a chuck mechanism for clamping and fixing the neck portion from the outside by a plurality of claws or the like that are operated by hydraulic pressure or air pressure. It may be fixed to the table 11.

  In the above process, the pre-processing head 1 a is positioned at a predetermined position in the axis z direction of the shaft hole 6. That is, by inserting the shaft hole insertion portion 13 into the pre-processing head 1a until the hosel end surface 7 contacts the end surface 11a of the turntable 11, the pre-processing head 1a is positioned in the axis z direction (see FIG. 2). In the present embodiment, positioning in the axis z direction is performed by the hosel end surface 7, but other methods can be adopted as a positioning method in the axis z direction. For example, a contact portion (for example, a bottom surface portion) is provided at the head inner side end portion of the shaft hole 6, and the shaft hole insertion portion 13 is inserted until the tip of the shaft hole insertion portion 13 comes into contact with the contact portion. Also good.

  In the second step, at least one point on the pre-processing head 1a fixed in the first step is set as the specific point p, and the three-dimensional coordinates of the specific point p are measured. The specific point p may be a point where the three-dimensional coordinate and the phase angle of the pre-processing head 1a around the axis line z correspond one to one. Therefore, if it is a normal golf club head, the specific point p can be set at almost all points on the outer surface of the pre-processing head 1a. However, since the specific point p is a point for measuring the three-dimensional coordinates, the specific point p is set to a point at which the coordinates can be measured by the three-dimensional measuring device 20.

  As described above, although the degree of freedom of setting the specific point p is high, in the present embodiment, the protrusion t for the specific point is provided on the pre-processing head, and a predetermined point on the protrusion t (for example, the protrusion t Is set as the specific point p. In this way, since the protrusion t serves as a mark, the position of the specific point p is further clarified, and the accuracy of the three-dimensional measurement of the specific point p can be increased. Moreover, in order to make the specific point p conspicuous, the specific point p may be marked with a white seal or paint. In the present embodiment, the protrusion t for the specific point is provided on the toe side upper portion on the face surface. As will be described later, the projecting portion t is finally cut away, so that the position of the projecting portion t is not limited. However, by providing the projecting portion t on the face portion 2 having a relatively large thickness among the head portions, the projecting portion It is possible to minimize the risk that the head is slightly deformed during the cutting of t. In addition, by providing the protrusion t at the peripheral edge of the face surface (for example, outside the face line area), even if a certain situation that the protrusion t affects the face portion 2 occurs, the head according to this The impact on the hit ball performance can be minimized.

  In addition, as a device for clarifying the specific point p, there is the following method in addition to the case where the protrusion t for the specific point is provided as described above. For example, a plurality of face lines and markings (dots, etc.) are usually provided on the face surface of the head, and an end point of a specific face line among the plurality of face lines is set as a specific point p, The marking may be a specific point p. Further, a specific end point or the like in a logo mark or the like provided on the surface of the sole portion 4 or the crown portion 3 may be set as the specific point p. Furthermore, a point where boundary lines such as the face part 2, the crown part 3, the sole part 4 and the side part 5 intersect may be set as the specific point p.

  And the three-dimensional coordinate of the specific point p set using the three-dimensional measuring device 20 is measured. In this embodiment, a non-contact type three-dimensional measuring device is used. The three-dimensional measuring instrument 20 has two CCD cameras 21 arranged on the left and right sides and a projector 22 arranged in the center. Then, the fringe pattern (striped pattern) projected from the projector 22 is measured by the two CCD cameras 21 in a stereo manner, and the three-dimensional coordinates of the specific point p are obtained by the principle of triangulation. As the three-dimensional measuring device 20 having such a configuration, for example, there is an “ATOS” series manufactured by GOM (Germany). In addition, as a non-contact three-dimensional measuring device of a type having a single camera and a projector that generates a stripe pattern, for example, “opto TOP-HE” manufactured by Breuckmann (Germany) is available. . In this type of three-dimensional measuring device with one camera, the distance and angle relationship between the camera and the projector is set, and the change in the stripe pattern reflected on the camera is replaced with three-dimensional coordinate data by image processing. Thus, in the present invention, various commercially available three-dimensional measuring instruments can be used.

  In addition, as a three-dimensional measuring device, you may use the contact-type thing which measures a three-dimensional coordinate by a contactor contacting a measurement point. However, in the case of the contact type, the specific point p of the pre-processing head 1a is moved by contact of the contactor, and the position of the pre-processing head 1a is displaced, which may eventually lead to a head positioning error. Therefore, it is preferable to measure the three-dimensional coordinates of the specific point p in a non-contact manner.

  As a method of measuring the three-dimensional coordinates of the specific point p, a DLT method (Direct Linear Transformation method) may be used in addition to the case of using a three-dimensional measuring device as described above. Hereinafter, the DLT method will be described with illustration omitted. In the DLT method, camera constants (position of the camera in the space, direction of the optical axis, lens focal length, etc.) appearing in the equation for constructing the three-dimensional coordinates are converted into points (control points and points having known real space coordinates). This is a method for obtaining three-dimensional coordinates without directly obtaining camera constants. Therefore, there are advantages in that there are few restrictions on camera installation. The DLT method is used in the field of sports and the like when measuring the motion of a human body three-dimensionally. The DLT method is disclosed in, for example, pages 191 to 195 of the following document “Japan Journal of Sports Science 10-3, 1991”.

In order to improve measurement accuracy by the DLT method, it is preferable to use two or more cameras. Then, a control point whose three-dimensional coordinates are known is set within the range of the visual field of the camera. In order to increase the measurement accuracy, six or more control points are preferably provided. The outline of the measurement procedure by the DLT method is as follows.
(1) Two (or more) cameras are installed so that a specific point p to be measured is reflected.
(2) A control point whose three-dimensional coordinates are known is arranged in a space to be measured (for example, around the pre-processing head 1a).
(3) Shoot the control point with the camera.
(4) Photograph a specific point p.
(5) Coordinates (two-dimensional coordinates) on the film of the control point on the film or video image (two-dimensional coordinates) are measured from the images (films, video images, etc.) obtained by the camera shooting, and simultaneous including unknown camera constants Solve the equation to determine the camera constant.
(6) The coordinates (two-dimensional coordinates) on the film or video image of the specific point p photographed by a plurality of cameras are measured, and the measured values and the camera constants obtained in the above (5) are used. The three-dimensional coordinates of the specific point p are obtained.

  This DLT method can measure the three-dimensional coordinates of the specific point p in a non-contact manner, and therefore is preferable in that the specific point p of the pre-processing head 1a does not move due to contact with a contact or the like, and the measurement accuracy can be improved.

  Note that the three-dimensional coordinates of the specific point p can also be determined from a two-dimensional image obtained by a camera. For example, when the pre-processing head 1a is photographed from a predetermined angle with one camera, the coordinates (two-dimensional coordinates) of the specific point p on the image (two-dimensional image) obtained by this camera and the specific point p The shooting angle of the camera or the specific point p can be set so that the three-dimensional coordinates correspond one-to-one. Therefore, in this case, the three-dimensional coordinates of the specific point p can be obtained from the coordinates (two-dimensional coordinates) of the specific point p on the two-dimensional image obtained by the camera.

  In the third step, the rotation angle of the head for arranging the specific point p at a predetermined reference position is obtained based on the three-dimensional coordinates of the specific point p measured in the second step. The reference position is a head state when the head is processed, and is a state in which the posture and position of the head are uniquely determined. If the reference posture is determined, the three-dimensional coordinates of the specific point p in the reference posture (that is, the reference position of the specific point p) can be determined in advance, so the head before processing in a state where the three-dimensional coordinates are measured. The rotation angle around the axis z for setting 1a as the reference posture is easily calculated.

An example of angle calculation is shown below. Here, in order to simplify the calculation of the rotation angle, as shown in FIG. 1, three axes (X axis, Y axis, Z axis) is set. In this case, the pre-processing head 1a has a fixed position in the Z-axis direction and rotates around the axis line z of the shaft hole, so the Z coordinate of the specific point p is the rotation angle (phase) of the pre-processing head 1a. Regardless. Therefore, the calculation of the rotation angle results in the problem of the rotation transformation matrix in the two-dimensional coordinate system composed of the X axis and the Y axis. That is, the three-dimensional coordinates of the specific point p before the head rotation measured by a three-dimensional measuring instrument or the like are set to (x, y, z), and the three-dimensional coordinates of the specific point p in the predetermined reference posture are set to (x ′ , Y ′, z ′), z = z ′, and when the rotation angle of the pre-processing head 1a from the state at the time of measuring the three-dimensional coordinates of the specific point p to the reference posture is θ, (A) and (B) hold.
x ′ = x × cos θ−y × sin θ (A)
y ′ = x × sin θ + y × cos θ (B)
Therefore, θ can be obtained by substituting the measured value (x, y) and the preset value (x ′, y ′) into the above formula (A) or formula (B). .
Thus, the calculation of the rotation angle can be simplified by matching one axis of the three-dimensional orthogonal coordinate system for determining the three-dimensional coordinate of the specific point p with the axis line z of the shaft hole.

  The rotation angle θ is calculated as described above, this angle information is given to the control unit 30, and the rotary table 11 is rotated about the axis z by θ by a servo motor (not shown), whereby the head 1a before processing is It becomes a specific reference posture. As in the prior art, there is no need to apply an abutting jig or to rely on the operator's visual observation, so the head positioning accuracy is significantly higher than in the prior art. FIG. 3 shows a state in which a reference posture is obtained by rotating θ degrees around the axis line z of the shaft hole from the state of FIG. There is no particular limitation on how to make the reference posture. For example, the reference posture can be set so that the head is in a posture and position that facilitates machining such as CNC machining.

  In the fourth step, the pre-processing head 1a is processed by processing data corresponding to the reference posture while maintaining the reference posture. As shown in FIG. 3, CNC machining is performed by the end mill 40 or the like in a state where the pre-machining head 1a in the reference posture is fixed in the reference posture. In the present embodiment, as shown in FIG. 5, the initial opening k1 is enlarged to form a finished opening k2. Since this processing data is data corresponding to the reference posture, the intended processing can be performed by processing the pre-processing head 1a having the reference posture based on the processing data. In the present embodiment, not only the positioning accuracy at the time of head processing is improved, but also the processing is NC processing (numerical control processing), so the processing accuracy is further improved.

  Examples of head machining used in the present invention include NC machining by laser as well as NC machining by machining as described above. For example, in laser cutting processing, welding processing, surface modification processing, and the like, NC processing is performed on the laser head with data corresponding to the reference posture, thereby enabling high-precision processing. As the laser, for example, a carbon dioxide laser can be used. Further, machining by an NC-controlled welding robot can also be suitably used in the present invention. As a welding method, plasma welding, TIG welding, or the like can be appropriately employed in addition to the above laser welding.

  As a result of the initial opening k1 being enlarged by NC processing to be the finishing opening k2, the contour shape of the finishing opening k2 is formed by NC processing. Therefore, the dimensional error due to the casting method or the forging method is eliminated by NC processing, and the dimensional accuracy of the opening is remarkably improved. In order to ensure that the pre-processing head 1a is fixed in the reference posture during processing, a support member (not shown) for maintaining the reference posture after rotating around the axis z to the reference posture. ) May be processed while supporting the pre-processing head 1a.

  In the present embodiment, the projection t for a specific point is also cut during the NC processing in which the initial opening k1 is enlarged to form the finished opening k2. After the NC processing using the initial opening k1 as the finish opening k2, a process of cutting the protrusion t may be performed separately. However, by cutting the protrusion during the NC processing, the protrusion t is separately formed. Since the cutting work is not necessary, the productivity of the head is improved. In addition, since the projecting portion t becomes the finished product head after being cut off, the projecting portion t does not affect the hitting performance of the head. Therefore, the protrusion t can be provided without being restricted by its position and shape. Therefore, it is possible to freely set the specifications (position, shape, etc.) of the protrusion t in consideration of the ease of measurement of the three-dimensional coordinates of the specific point p.

  In the above embodiment, only one specific point p is used, but a plurality of specific points p may be set. Setting two or more specific points p further increases the head positioning accuracy. When a plurality of specific points p are set, for example, a method of rotating the head by the average value of the rotation angles θ obtained based on the specific points p can be employed. For example, when there are two specific points p, the rotation angle θ1 for obtaining the reference posture is obtained based on the first specific point p1, and the reference posture is obtained based on the second specific point p2. The rotation angle θ2 is obtained, and the method of setting the rotation angle of the head to [(θ1 + θ2) / 2] can be employed.

In the above embodiment, the rotation angle θ to the reference posture is obtained based on the coordinates of the specific point p, but the rotation angle θ to the reference posture may be obtained based on the contour shape of the head. The process in this case will be described below.
Also in the case of obtaining the rotation angle θ to the reference posture based on the contour shape of the head, the first step and the fourth step are the same as in the above embodiment, so the description thereof will be omitted, and a second step different from the above embodiment and The third step will be described.

  In the second step, a two-dimensional image is taken from at least one direction in the pre-processing head 1a fixed rotatably in the first step. Unlike a sphere or the like, a golf club head has an indefinite shape having a free curved surface and the like, so the contour shape of the head changes depending on the position of the viewpoint. Therefore, there is a one-to-one correspondence between the head contour shape and the head posture, and the head posture can be specified by specifying the head contour shape. Therefore, in the third step, the second contour is obtained by comparing the plurality of head contour shapes obtained based on the three-dimensional data of the pre-processed head prepared in advance with the head contour shape of the two-dimensional image obtained in the second step. The head posture in the process is specified, and based on this, the head rotation angle for obtaining the reference posture is obtained.

  If there is three-dimensional data of the head 1a before processing, the contour shape of the head 1a before processing viewed from an arbitrary viewpoint can be taken out. Therefore, the head contour shape obtained based on the three-dimensional data of the head 1a before processing is compared with the head contour shape of the two-dimensional image obtained in the second step, and a plurality of pieces extracted from the three-dimensional data of the head 1a before processing. 2D coordinates were photographed in the second step by searching for a contour shape that is the same as or approximated to the head contour shape obtained in the second step (hereinafter also referred to as contour shape search). The posture of the head at the time can be specified. Then, based on the identified head posture, the head rotation angle θ for setting the reference posture can be obtained.

  As a specific method of the contour shape search, for example, the following method can be employed. First, a plurality of different head contour shapes are extracted from the three-dimensional data of the head 1a before processing. In the following description, the head contour shape obtained from the three-dimensional data of the head 1a before processing is also referred to as a virtual contour shape. In order to facilitate the contour shape search, the extraction of the virtual contour shape should be limited to the virtual contour shape that can be photographed in the second step. In other words, it is preferable to limit the extracted virtual contour shape from the same viewpoint as the camera that captured the head in the second step. Then, as shown in FIG. 6, based on the three-dimensional data of the pre-machining head 1a, for example, the angle phase around the axis line z of the shaft hole is made to differ every predetermined angle (for example, evenly every α degrees). Are extracted in a second step, and the virtual contour shapes h1, h2, h3, h4,... The contour shape of the two-dimensional image g is compared. Then, in the phase range of the plurality of virtual contour shapes having the closest contour shape (here, h3) and the vicinity thereof (h2 and h4), the difference in phase angle is made finer than the primary extraction. A plurality of virtual contour shapes (not shown) having different phase angles (for example, equally α / 10 degrees) are extracted (this is referred to as secondary extraction), and the contour shape closest to the two-dimensional image g is extracted. decide. In the same manner, tertiary extraction, quaternary extraction,... Are performed as necessary, and finally a virtual contour shape that is the same as or closest to the two-dimensional image g is determined. Then, since the posture of the head of the two-dimensional image obtained in the second step is specified from the finally determined virtual contour shape, rotation about the axis z of the shaft hole to make this posture a reference posture Find the angle. The two-dimensional image g and the virtual contour shape do not necessarily need to be completely matched, and the most approximate virtual contour shape may be determined in consideration of an error allowed in the fourth process.

  In addition, as a method for determining the degree of approximation (adaptability) between the two-dimensional image g and the virtual contour shape h, the determination is based on the overlapping area ratio between the contour line of the two-dimensional image g and the contour line of the virtual contour shape. Can do. That is, as shown in FIG. 7, the two-dimensional image g and the virtual contour shape h are overlapped with the position of the axis line z of the shaft hole and the position of the hosel end surface 7 being coincident, and an overlapping portion T (solid hatching in FIG. 7). Area). Then, the ratio (ST / Sm) between the maximum area Sm of the portion surrounded by the contour line of the two-dimensional image g and the contour line of the virtual contour shape h (indicated by broken line hatching in FIG. 7) and the area ST of the overlapping portion T ) Is larger, it can be determined that the degree of approximation between the virtual contour shape h and the two-dimensional image g is higher. Note that in order for the computer to automatically recognize the contour shape of the two-dimensional image g, it is possible to employ a technique such as using a binarization process that displays only white and black on the captured image. In order to recognize the virtual contour shape from the three-dimensional data, for example, a parting line creation function or a contour creation function possessed by general-purpose three-dimensional CAD software may be used.

As the binarization processing method described above, for example, there is a method of extracting a head silhouette by performing background difference processing between a background image in which the head is not reflected and an image with a head in which the head is reflected together with the background. Specifically, when the RGB value of each pixel of the background image is r ′, g ′, b ′ and the RGB value of each pixel of the image with the head is r, g, b, respectively, If the value of the norm shown in (A) (the square root of the square sum of the absolute values of the differences between r, g, b and r ′, g ′, b ′ at the target pixel) is less than a preset threshold value, the head It is assumed that the pixel is not a silhouette, and the pixel is set to 0. If the norm value is equal to or greater than the threshold value, the pixel is set to 1, and labeling processing is sequentially performed on one pixel. Thus, a binarized image (binarized image) can be obtained.
[(R−r ′) ² + (g−g ′) ² + (b−b ′) ² ] ^1/2 (A)

Furthermore, for example, the following method can be employed to extract the contour from the binarized image. As shown in FIG. 8, the obtained binarized image 2g is sequentially scanned in the right direction from the top to the bottom of the screen starting from the pixel (a, 1) at the upper left in the image frame. (See the dashed arrow in FIG. 8), specify the first pixel (d, 7) found. The pixel (d, 7) refers to a pixel having a vertical coordinate code b2 of d and a horizontal coordinate number b1 of 7 attached to the binarized image 2g in FIG. Then, the eight pixels around the pixel (d, 7) are sequentially examined from the upper left pixel in the clockwise direction, and the labeled pixel that has been found first (pixel (d, 8) in the example of FIG. 8) is designated. Next, among the eight pixels around the pixel (d, 8), except for the pixel (d, 7) specified immediately before, the pixel from the upper left pixel [pixel (c, 7)] is clocked. Sequentially check around and specify the first labeled pixel (pixel (d, 9) in the example of FIG. 8) found first. This process is then repeated sequentially to return to the first designated pixel (d, 7). At this point, the contour extraction is finished, and each pixel specified by the contour extraction operation becomes a contour. Runode preferably kept over smoothing by performing moving average processing circulate throughout contour.
In FIG. 8, the binarized image 2g is not a golf club head image but a simplified image (displayed in black) for easy understanding.

  In the above embodiment, the rotation angle θ for obtaining the reference posture is obtained based on the two-dimensional image from one direction with one camera that captures the pre-processing head 1a in the second step. A two-dimensional image from two or more directions may be obtained by using a plurality of units, and the rotation angle θ may be obtained based on these. In the above embodiment, the virtual contour shape h most approximated to the two-dimensional image g is determined by performing extraction in multiple stages, such as primary, secondary, and so on, and gradually narrowing the angle range. In addition to the method, for example, a virtual contour shape h that is most approximate to the two-dimensional image g can be obtained by a genetic algorithm. In this case, the ratio (ST / Sm) described above is used as the fitness evaluation, and the higher the ratio (ST / Sm) (closer to 1), the higher the fitness can be evaluated.

  In the said embodiment, although the crown part 3 was processed, it does not specifically limit about a process part in this invention. However, when the processing site is located on the curved surface portion, the processing is three-dimensional and high-precision processing is required, so the present invention is effective. In particular, when the processing site is located on the free-form surface portion as in the above-described embodiment, more precise processing is required, and the effectiveness of the present invention is further enhanced. The present invention is also effective for head processing that requires a thin wall and high accuracy, such as a hollow head. Particularly in recent heads, the wall thickness is about 0.5 mm to 3 mm, and especially in the crown portion or the like, the wall thickness is about 0.5 to 1.5 mm. The present invention is particularly effective. Further, when the outer surface of the pre-processing head 1a does not have a flat surface as in the head of the above-described embodiment, accurate positioning is difficult with the conventional method, and the effectiveness of the present invention is particularly high.

1 is an overall perspective view showing an embodiment of the present invention. It is a figure which shows the state which inserted and fixed the head before a process in the shaft hole insertion part. FIG. 3 is a diagram showing a state in which the pre-processing head is in a reference posture by rotating the pre-processing head by a predetermined angle around the axis of the shaft hole from the state of FIG. 2. It is the figure which looked at the head before a process from the crown part side. It is the figure which looked at the head after a process from the crown part side. It is a figure for demonstrating the comparison with a virtual outline shape and a two-dimensional image. It is a figure for demonstrating how to obtain | require the approximation degree of a virtual outline shape and a two-dimensional image. It is a figure for demonstrating a binarization process.

Explanation of symbols

1a Head before processing 1b Head after processing 6 Shaft hole r Rotating axis z Shaft hole axis

Claims (5)

  A first step of fixing the pre-processing head positioned at a predetermined position in the axial direction of the shaft hole and being rotatable about the axis; and at least one specific point on the pre-processing head fixed in the first step A second step of measuring three-dimensional coordinates, and a rotation angle of a head for arranging the specific point at a predetermined reference position based on the three-dimensional coordinates of the specific point measured in the second step, A third step of setting the pre-processing head to a specific reference posture by rotating the pre-processing head around the axis by a rotation angle, and processing data corresponding to the reference posture while maintaining the reference posture. A fourth method of manufacturing a golf club head, comprising: a fourth step of processing the head.   Protruding portions for the specific points are provided on the pre-machining head, the specific points are set on the protruding portions, and the protruding portions are cut when the head is processed in the reference posture. The method for manufacturing a golf club head according to claim 1.   A first step of fixing the pre-processing head in a state where the shaft hole is positioned at a predetermined position in the axial direction of the shaft hole and being rotatable around the axis, and two from at least one direction in the pre-processing head fixed in the first step A specific reference posture by comparing a second step of capturing a two-dimensional image, and a plurality of head contour shapes obtained based on three-dimensional data of a pre-processed head prepared in advance and a head contour shape obtained from the two-dimensional image. A rotation angle of the head for performing, and a third step of setting the pre-processing head to the reference posture by rotating the pre-processing head around the axis by the rotation angle, and maintaining the reference posture And a fourth step of processing the pre-processing head with processing data corresponding to a reference posture. The golf club head has a joint portion formed by joining a plurality of members and positioned on a curved surface portion of the head,
The method of manufacturing a golf club head according to claim 1, wherein the processing of the head includes processing of the joint portion.   The golf club head manufacturing method according to claim 1, wherein the golf club head is a hollow wood-type golf club head.

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