JP7429976B2 - Ring manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing a ring by forging.

Ring manufacturing methods include a manufacturing method using lost wax (casting) and a manufacturing method using forging, in which the outer peripheral surface is cut after a process of hammering and rolling the material. Lost wax rings can be freely designed and can be made into complex shapes, but they have the disadvantage of being weak and easily scratched on the surface. On the other hand, forged rings have high strength and are hard to scratch on the surface, but they have the disadvantage that it is difficult to design them freely and only simple shapes can be produced.

As disclosed in Patent Document 1, forged rings are made by rolling a ring formed into a substantially cylindrical shape by forging and sandwiching it between rotating rollers from the inner and outer circumferential sides to expand the diameter. It is made to the desired size. At this time, by forming a concave surface on the roller that contacts the inner circumferential surface, a bulging surface is formed on the inner circumferential surface of the ring. However, with this method, the bulging surface could only be processed into a gentle radius.

Japanese Patent Application Publication No. 2004-305508

In view of the above-mentioned circumstances, it is an object of the present invention to provide a ring manufacturing method that allows a ring to be designed freely on the inner peripheral surface of the ring by forging.

In order to achieve the above object, a ring manufacturing method according to the invention according to claim 1 includes a step of punching a washer-shaped ring material from a plate of precious metal, and a drawing step of forming the ring material into a substantially cylindrical ring. , a rolling process in which the ring is sandwiched between inner and outer circumferential sides between rollers, and a cutting process in which the end face, outer circumferential surface, and inner circumferential surface of the rolled ring are cut. The rough machining process involves cutting to the inner diameter dimension, and the apex part of the cutting tip with an apex angle of 90° or less is applied to the inner circumferential surface in a direction such that the bisector of the apex angle is perpendicular to the axial direction of the ring. It is characterized by having a finishing process of forming a groove or a rounded surface on the inner circumferential surface by cutting along.

The method for manufacturing a ring according to the invention described in claim 2 includes the steps of punching out washer-shaped ring materials from plates of different types of precious metals, and stacking a plurality of washer-shaped ring materials made of different types of precious metals and hot pressing them. The process includes a process of joining the ring to form a substantially cylindrical ring, and a cutting process of cutting the end face, outer circumferential surface, and inner circumferential surface of the ring. Cutting the inner circumferential surface is a rough machining process in which the inner circumferential surface is cut to a predetermined inner diameter dimension. The process involves applying the apex part of a cutting tip with an apex angle of 90° or less to the inner peripheral surface in a direction such that the bisector of the apex angle is perpendicular to the axial direction of the ring, and cutting along the circumferential direction. , is characterized by having a finishing process of forming a groove or a rounded surface on the inner circumferential surface.

The method for manufacturing a ring according to the invention set forth in claim 3 includes a step of punching out a washer-shaped ring material from a plate of precious metal, a drawing step of forming the ring material into a substantially cylindrical ring, and an inner peripheral side of the ring. It includes a rolling process in which the ring is sandwiched between rollers from the outer circumferential side and expanded, and a cutting process in which the end face, outer circumferential surface, and inner circumferential surface of the rolled ring are cut. , a finishing process in which a rounded surface is formed on the inner circumferential surface by applying the apex part of a cutting tip with an apex angle of 90° or less to the inner circumferential surface in a direction perpendicular to the axial direction of the ring and cutting along the circumferential direction. The finishing process of forming a rounded surface on the inner circumferential surface divides the inner circumferential surface into a left half region and a right half region, and separates each region by moving the cutting edge toward or away from the ring . It is characterized by cutting while moving in one direction.

The method for manufacturing a ring according to the invention according to claim 4 includes the steps of punching out washer-shaped ring materials from plates of different types of precious metals, and stacking a plurality of washer-shaped ring materials made of different types of precious metals and hot pressing them. The process includes a process of joining the ring to form a substantially cylindrical ring, and a cutting process of cutting the end face, outer circumferential surface, and inner circumferential surface of the ring. Cutting the inner circumferential surface is a rough machining process in which the inner circumferential surface is cut to a predetermined inner diameter dimension. Process and finishing process to form a rounded surface on the inner circumferential surface by applying the apex part of a cutting tip with an apex angle of 90° or less to the inner circumferential surface in a direction perpendicular to the axial direction of the ring and cutting along the circumferential direction. The finishing process of forming a rounded surface on the inner circumferential surface divides the inner circumferential surface into a left half region and a right half region, and each region is divided into two regions: the cutting edge is moved toward or away from the ring. It is characterized by cutting while moving in one direction.

The method for manufacturing a ring according to the invention according to claim 1 includes the steps of punching a washer-shaped ring material from a plate of precious metal, a drawing step of forming the ring material into a substantially cylindrical ring, and forming the ring on the inner peripheral side. It includes a rolling process in which the ring is sandwiched between rollers from the outer circumferential side and expanded, and a cutting process in which the end face, outer circumferential surface, and inner circumferential surface of the rolled ring are cut. , by applying the apex part of a cutting tip with an apex angle of 90° or less to the inner circumferential surface in a direction such that the bisector of the apex angle is perpendicular to the axial direction of the ring , and cutting along the circumferential direction. By having a finishing process that forms grooves or rounded surfaces on the circumferential surface, it is possible to freely design the inner circumferential surface of a forged ring. It can improve the feeling of wearing and reduce weight.

The method for manufacturing a ring according to the invention described in claim 2 includes the steps of punching out washer-shaped ring materials from plates of different types of precious metals, and stacking a plurality of washer-shaped ring materials made of different types of precious metals and hot pressing them. The process includes a process of joining the ring to form a substantially cylindrical ring, and a cutting process of cutting the end face, outer circumferential surface, and inner circumferential surface of the ring. Cutting the inner circumferential surface is a rough machining process in which the inner circumferential surface is cut to a predetermined inner diameter dimension. The process involves applying the apex part of a cutting tip with an apex angle of 90° or less to the inner peripheral surface in a direction such that the bisector of the apex angle is perpendicular to the axial direction of the ring, and cutting along the circumferential direction. By having a finishing process that forms grooves or rounded surfaces on the inner circumferential surface, it is possible to freely design the inner circumferential surface of a forged ring. It can improve the feeling of wearing and reduce weight. Furthermore, the ring manufactured by this manufacturing method can have an even higher design quality by combining different types of precious metals.

In the method for manufacturing a ring according to the invention described in claims 3 and 4 , the finishing step of forming the rounded surface on the inner circumferential surface divides the inner circumferential surface into a left half region and a right half region, and each region is divided into a cutting edge. By cutting while moving the ring in one direction, either toward or away from the ring, it is possible to prevent the formation of streaks due to backlash in the center of the R surface.

It is a figure which shows typically the manufacturing process of the ring by this invention. 1 is a longitudinal sectional view showing a first embodiment of a ring according to the present invention, in which (a) is a state before cutting the inner circumferential surface, (b) is a state after rough processing the inner circumferential surface, and (c) is a state in which the inner circumferential surface is rough-machined; FIG. Shows the state after finishing the peripheral surface. It is a figure which shows the cutting tool when rough-machining an inner peripheral surface. It is a figure which shows the movement of the cutting tool when rough-machining an inner peripheral surface. It is a figure which shows the cutting tool at the time of finish-processing an inner peripheral surface. It is a figure which shows the procedure when finishing-processing an inner peripheral surface. FIG. 7 is a vertical cross-sectional view showing a second embodiment of a ring according to the present invention, in which (a) is a state before cutting the inner circumferential surface, (b) is a state after rough processing the inner circumferential surface, and (c) is a state in which the inner circumferential surface is rough-machined. Shows the state after finishing the peripheral surface. It is a figure which shows the movement of the cutting tool in the finishing process of the inner peripheral surface of the ring of 2nd Embodiment. It is a figure which shows other embodiment of the manufacturing method of the ring by this invention. FIG. 7 is a vertical cross-sectional view showing a third embodiment of a ring according to the present invention, in which (a) is a state before cutting the inner circumferential surface, (b) is a state after rough processing the inner circumferential surface, and (c) is a state in which the inner circumferential surface is rough-machined. Shows the state after finishing the peripheral surface. FIG. 3 is a reference diagram showing a state when attempting to finish the inner circumferential surface of a ring using a standard cutting tool. It is a figure which shows the example when a groove|channel is machined on the inner peripheral surface of a ring using the cutting tip with an apex angle of 80 degrees. It is a figure which shows the example when a R surface is machined on the inner peripheral surface of a ring using the cutting tip with an apex angle of 80 degrees. Compare the case where a groove is machined on the inner circumferential surface of a ring using a cutting tip with an apex angle of 90° and the case where a groove is machined on the inner circumferential surface of a ring using a cutting tip with an apex angle of 35°. FIG. Compare the case where a groove is machined on the inner circumferential surface of a ring using a cutting tip with an apex angle of 10 degrees and the case where a groove is machined on the inner circumferential surface of a ring using a cutting tip with a apex angle of 35 degrees. FIG. It is a figure showing an example of the ring manufactured by the manufacturing method of the present invention.

Embodiments of the present invention will be described below based on the drawings. FIG. 1 schematically shows each step of the ring manufacturing method according to the present invention.
A method for manufacturing a ring according to the present invention will be explained with reference to FIG. First, an ingot of precious metal such as gold or platinum is hammered in a heated state, and then, as shown in Figure 1(a), it is passed between a pair of rotating rollers 10, 10 and rolled to a predetermined thickness. .
Thereafter, a washer-shaped ring material 11 as shown in FIG. 1(b) is punched out from the rolled plate material using a press machine.
Next, as shown in FIG. 1(c), the washer-shaped ring material 11 is drawn with a press to form a mortar shape, and then drawn again to form a substantially cylindrical ring 12. do.
Next, as shown in FIG. 1(d), rotating rollers 13 and 14 are pressed against the ring 12 from the inner circumferential side and the outer circumferential side to stretch it, thereby making the ring 12 thinner and expanding its diameter at the same time.
Next, as shown in FIG. 1(e), the inner peripheral surface of the ring 12 is held in a chuck 16 of a lathe via a jig 15, and the end surface 17 and outer peripheral surface 18 of the ring 12 are cut with a cutting tool 19. .
Next, as shown in FIG. 1F, the outer peripheral surface 18 of the ring 12 is held in the chuck 16 of the lathe via the jig 20, and the inner peripheral surface 21 of the ring 12 is cut with the bits 22 and 23.

The ring manufacturing method of the present invention is characterized by the step shown in FIG. 1(f), that is, cutting the inner circumferential surface 21 of the ring 12 using a lathe (CNC automatic lathe). The cutting of the inner circumferential surface 21 involves a rough machining process in which a standard cutting tool 22 is used to cut the inner diameter to a predetermined dimension, and a finishing step in which a groove 24 or a rounded surface 25 is formed on the inner circumferential surface 21 using a special cutting tool 23. It has a processing process.

FIG. 2 shows a first embodiment of a ring manufactured by the ring manufacturing method of the present invention. As shown in FIG. 2(c), this ring has an inner diameter of 14 mm and a width of 5 mm, and a groove 24 is formed continuously in the circumferential direction on the inner peripheral surface 21.
In the state before cutting the inner circumferential surface 21, as shown in FIG. 2(a), the inner diameter is 13.5 mm. In the rough machining step, as shown in FIG. 2(b), cutting is performed to an inner diameter of 13.9 mm. Thereafter, in a finishing process, the inner circumferential surface 21 is cut into an uneven shape having grooves 24.

FIG. 3 shows a cutting tool 22 used in the rough machining process. This cutting tool 22 has a commercially available cutting tip 27 attached to a commercially available shank 26, and the cutting tip 27 has a diamond shape with an apex angle α of 55°. This cutting tool 22 is attached to the tool rest of the lathe with the shank 26 tilted.
For rough machining, move the cutting tool 22 to the left to insert the cutting tip 27 into the ring 12, as shown in FIG. 4(a), and then move the cutting tool 22 toward the front as shown in FIG. 4(b). The cutting tip 27 is moved to bring the cutting edge of the cutting tip 27 into contact with the inner peripheral surface 21 of the ring 12. Next, as shown in FIG. 4(c), the inner circumferential surface 21 of the ring 12 is cut while moving the cutting tool 22 rightward. The steps in FIGS. 4(a) to 4(c) are repeated until the inner diameter reaches a predetermined size.

FIG. 5 shows a cutting tool 23 used in the finishing process. This cutting tool 23 is newly designed for cutting the inner peripheral surface 21 of a ring, and has a shank 28 and a cutting tip 29 attached to the tip of the shank 28. The cutting tip 29 has a narrow apex angle β of 35°, and blades 30, 30 are formed symmetrically. The distal end 31 of the cutting tip 29 is cut off straight to allow the cutting tip 29 to be inserted inside the small ring 12 without interference. The cutting tool 23 is attached to a tool rest of a lathe with the shank 28 oriented parallel to the axis of the ring 12, and the cutting tip 29 oriented perpendicular to the axial direction of the ring 12.

FIG. 6 shows the procedure for finishing the inner circumferential surface 21. As shown in FIG. First, as shown in FIG. 6(a), the cutting edge 32 of the cutting tip 29 is visually aligned with the inner corner of the ring 12, and the position of the cutting edge 32 at this time is registered in the NC.
Next, as shown in FIG. 6(b), the inner circumferential surface 21 is shallowly shaved with the apex corner of the cutting tip 29 along the shape 33 to be finished. Thereafter, the left-right balance of the shape of the cut surface is visually checked, and if it is biased to either the left or right, the position of the cutting edge 32 previously registered in the NC is corrected. In the enlarged view (top) of the figure, it is biased to the left, so correct the position of the cutting edge 32 slightly to the right so that the left and right balance is the same, as shown in the enlarged view (bottom) of the figure. .
Then, the cutting tool 23 is moved according to a pre-registered program to cut the inner circumferential surface 21 according to the desired shape using the top corner of the cutting tip 29, as shown in FIG. 6(c).
In this cutting tool 23, since the blades 30, 30 of the cutting tip 29 are symmetrical and inclined, it is not easy to accurately align the position of the cutting edge 32 with respect to the ring 12. By correcting this, the inner circumferential surface can be precisely machined as designed.

The ring of this embodiment has grooves 24 formed on the inner circumferential surface 12, so that the contact area with the finger is reduced, so it is easy to put on and take off the finger, and it is comfortable to wear. Also, the weight of the ring can be reduced by the amount removed.

FIG. 7 shows a second embodiment of a ring manufactured by the ring manufacturing method of the present invention. As shown in Fig. 2(c), this ring has an inner diameter of 14 mm and a width of 2.5 mm, and an R surface 25 is formed on the inner circumferential surface 21 with the central part in the width direction bulging inward. It has been done. The R surface 25 has a very small R of R1.1 and R0.4.
In the state before cutting the inner circumferential surface 21, as shown in FIG. 7(a), the inner diameter is 13.5 mm. In the rough machining step, as shown in FIG. 7(b), cutting is performed to an inner diameter of 13.9 mm. Thereafter, in a finishing process, the inner circumferential surface 21 is cut into a shape having a rounded surface 25. Finishing can be done using the same special cutting tool 23 as previously described.

FIG. 8 shows the movement of the cutting tool 23 when cutting the R surface 25. Cutting of the R surface 25 is performed by dividing the inner circumferential surface 21 of the ring 12 into a left half region and a right half region, and moving the cutting edge 32 in each region in one direction, either toward or away from the ring 12. At the same time, the inner circumferential surface 21 is cut with the apex corner portion of the cutting tip 29. Specifically, as shown in FIG. 8(a), the left half area of the inner circumferential surface 21 is cut while moving the cutting edge 32 rightward and away from the ring 12, and as shown in FIG. 8(b). As shown, the right half region of the inner circumferential surface 21 is cut while moving the cutting edge 32 leftward and away from the ring 12. Note that each region can also be cut while moving the cutting edge 32 in a direction approaching the ring 12.

When machining the R surface 25 on the inner circumferential surface of the ring 12, if the cutting is continued from the left end to the right end, the direction of the forward and backward movement of the cutting edge 32 will change midway, so the center part of the inner circumferential surface will Streaks appear due to backlash. As described above, by dividing the area into the right half area and the left half area and cutting while moving the cutting edge 32 in the same front-back direction, a line due to backlash is formed in the center of the inner circumferential surface 21. You can prevent this from happening.

Since the ring of this embodiment has the rounded surface 25 formed on the inner circumferential surface 21, the contact area with the finger is reduced, so it is easy to put on and take off the finger, and the ring is comfortable to wear. Also, the weight of the ring can be reduced by the amount removed.

For reference, FIG. 11 shows a case where an attempt is made to cut the inner peripheral surface 21 of the ring 12 using a standard cutting tool 22 (equipped with a commercially available cutting tip 27 with an apex angle of 90°). When using the standard cutting tool 22 in this way, the blade 30 interferes regardless of the mounting angle of the cutting tool 22, making it impossible to form a rounded surface with a small radius. Groove machining is similarly impossible with the standard cutting tool 22.
As shown in FIGS. 5, 6, and 8, in the present invention, the apex portion of the cutting tip 29 having an apex angle β of 35° is applied to the inner circumferential surface 21 in a direction perpendicular to the axial direction of the ring 12, and the cutting tip 29 is cut along the circumferential direction. By cutting the ring 12, it becomes possible to process the fine grooves 24 and the rounded surface 25, and it becomes possible to freely design the inner circumferential surface 21 of the ring 12.

FIG. 16 shows an example of a ring manufactured by the manufacturing method of the present invention. As described above, according to the manufacturing method of the present invention, it is possible to create a complicated design having fine grooves 24 and rounded surfaces 25 on the inner circumferential surface 21 of the ring.

FIG. 12 shows an example of cutting a groove 24 on the inner circumferential surface 21 of the ring 12 using a cutting tip 29 with an apex angle β of 80°, and FIG. 13 shows a cutting tip 29 with an apex angle β of 80°. 29 is used to process the R surface 25 on the inner circumferential surface 21 of the ring. As shown in these figures, even when the cutting tip 29 with the apex angle β of 80° is used, there is no damage to the inner circumferential surface 21 of the ring 12, similar to when the cutting tip 29 with the apex angle β of 35° is used. Grooves 24 and rounded surfaces 25 can be formed.

The apex angle β of the cutting tip 29 can also be 90°, as shown in FIG. However, in that case, the degree of freedom in designing the inner circumferential surface 21 of the ring 12 is lower than when the apex angle β is 35°.
Further, the apex angle β of the cutting tip 29 can also be set to 10°, as shown in FIG. In this case, the degree of freedom in designing the inner circumferential surface 21 of the ring 12 is increased compared to the case where the apex angle β is 35°, but there is a risk that the cutting edge may be damaged.
When the apex angle β is about 35°±5° and about 80°, the degree of freedom in designing the inner circumferential surface 21 of the ring 12 is sufficiently high, and it also has sufficient strength and durability. , the cutting tip 29 can be made to last for a long time, and both workability and economic efficiency can be achieved.

FIG. 9 shows another embodiment of the ring manufacturing method according to the present invention, and FIG. 10 shows an example of a ring manufactured by this method (third embodiment). As shown in FIG. 10(c), this ring has a laminated structure in which platinum 34 is sandwiched between gold plates 35, 35 on both sides, and a groove 24 is formed in the inner circumferential surface 21. The width of the groove 24 is approximately the same as the width of the platinum 34 portion.

As shown in FIG. 9(a), the ring of this embodiment is made of a washer-shaped plate made of a different type of precious metal (a precious metal ingot is hammered in a heated state and then rolled to a predetermined thickness). The ring materials 11a and 11b are punched out, respectively. Next, as shown in FIG. 9(b), a plurality of washer-shaped ring materials 11a and 11b made of different kinds of precious metals are stacked (11a is gold, 11b is platinum) and subjected to high temperature and high pressure. (hot press), the surfaces of each ring material 11a, 11b are firmly joined together by diffusion bonding, and a substantially cylindrical ring material 12 is produced.
Next, as shown in FIG. 9(c), the inner peripheral surface of the ring 12 is gripped by a chuck 16 of a lathe via a jig 15, and the end surface 17 and outer peripheral surface 18 of the ring 12 are cut with a cutting tool 19. .
Next, as shown in FIG. 9D, the outer peripheral surface 18 of the ring 12 is held in the chuck 16 of the lathe via the jig 20, and the inner peripheral surface 21 of the ring 12 is cut with the bits 22 and 23. Cutting of the inner circumferential surface 21 can be performed in the same manner as in the first embodiment described above.

The ring manufacturing method described above is different from the manufacturing method shown in FIG. The difference is that the inner diameter is finished to a predetermined size only by cutting, without performing a rolling process for expanding (the process shown in FIG. 1(d)). This is because, in the case of dissimilar metals joined by hot pressing, there is a risk that the joints between the dissimilar metals will separate if a drawing process or a rolling process is performed. As in the manufacturing method of the present invention, by cutting the inner circumferential surface 21, it is possible to manufacture rings with various inner diameters without going through the drawing process and the rolling process, and moreover, it is possible to manufacture rings with various inner diameters using a special bit 23. This allows for free design on the inner circumferential surface.

As described above, the method for manufacturing a ring according to the present invention (first and second embodiments) includes the steps of punching out a washer-shaped ring material 11 from a plate of precious metal, and forming a ring material 11 into a substantially cylindrical ring. 12, a rolling process in which the ring 12 is sandwiched and expanded by rollers 13 and 14 from the inner and outer circumferential sides, and the end surface 17, outer circumferential surface 18, and inner circumferential surface 21 of the rolled ring 12 are cut. The cutting of the inner circumferential surface 21 includes a rough machining step of cutting to a predetermined inner diameter dimension, and a cutting step of cutting the apex portion of the cutting tip 29 with the apex angle β of 90° or less in a direction perpendicular to the axial direction of the ring 12. By having a finishing process in which grooves 24 or R surfaces 25 are formed on the inner circumferential surface 21 by applying it to the inner circumferential surface 21 and cutting along the circumferential direction, designs can be freely created on the inner circumferential surface of the forged ring. This can enhance the design of the ring, improve the feeling of wearing it on the finger, and reduce the weight.

Further, the method for manufacturing the ring (third embodiment) of the present invention includes the steps of punching out washer-shaped ring materials 11a and 11b from plates of different kinds of precious metals, and punching out washer-like ring materials made of different kinds of precious metals. A step of forming a substantially cylindrical ring 12 by stacking a plurality of sheets 11a and 11b and joining them by hot pressing, and a cutting step of cutting an end surface 17, an outer circumferential surface 18, and an inner circumferential surface 21 of the ring 12, The cutting of the inner circumferential surface involves a rough machining step in which the inner circumference is cut to a predetermined inner diameter dimension, and a vertex portion of a cutting tip 29 with an apex angle β of 90° or less is applied to the inner circumferential surface 21 in a direction perpendicular to the axial direction of the ring 12. By having a finishing process of forming grooves 24 or R surfaces 25 on the inner circumferential surface 21 by cutting along the circumferential direction, it is possible to freely design the inner circumferential surface of the forged ring. This makes it possible to enhance the design of the ring, improve the feeling of wearing it on the finger, and make it lighter. Furthermore, the ring manufactured by this manufacturing method can have an even higher design quality by combining different types of precious metals.

Furthermore, in the ring manufacturing method of the present invention, in the finishing process of forming the groove 24 on the inner peripheral surface 21, the position of the cutting edge 32 is registered by visually aligning the cutting edge 32 with the inner corner of the ring 12, The inner circumferential surface 21 of the ring 12 is shallowly shaved along the shape that you want to finish, and if the shape of the cut surface is biased to the left or right, the position of the cutting edge 32 is corrected by that bias. 21 can be processed accurately as designed.

Further, in the ring manufacturing method of the present invention, the finishing process of forming the rounded surface 25 on the inner circumferential surface 21 divides the inner circumferential surface 21 into a left half region and a right half region, and each region is divided into a cutting edge 32. By cutting while moving the ring 12 in one direction, either toward or away from the ring 12, it is possible to prevent the formation of streaks due to backlash in the center of the inner circumferential surface 21.

The invention is not limited to the embodiments described above. The shape of the groove or R surface formed on the inner peripheral surface of the ring can be changed as appropriate. A combination of grooves and rounded surfaces can also be formed on the inner peripheral surface of the ring. The material of the ring does not matter. Cutting of the inner circumferential surface is not limited to a CNC automatic lathe, but can also be performed with a normal lathe, machining center, etc.

11, 11a, 11b Ring material 12 Ring 21 Inner peripheral surface 24 Groove 25 R surface 29 Cutting tip

Claims (4)

A process of punching out a washer-shaped ring material from a plate of precious metal, a drawing process of forming the ring material into a substantially cylindrical ring, a rolling process of sandwiching the ring between inner and outer sides with rollers, and rolling. The cutting process involves cutting the end face, outer circumferential surface, and inner circumferential surface of the ring, and the cutting of the inner circumferential surface involves a rough machining process in which the inner circumferential surface is cut to a predetermined inner diameter dimension, and the apex corner of a cutting tip with an apex angle of 90° or less. A finishing process in which a groove or R surface is formed on the inner circumferential surface by applying it to the inner circumferential surface in a direction such that the bisector of the apex angle is perpendicular to the axial direction of the ring and cutting it along the circumferential direction. A method for producing a ring, characterized by having the following. A process of punching out washer-shaped ring materials from plates of different types of precious metals, and a process of stacking multiple sheets of washer-shaped ring materials made of different types of precious metals and joining them by hot pressing to form a substantially cylindrical ring. and a cutting process to cut the end face, outer circumferential surface, and inner circumferential surface of the ring, and the cutting of the inner circumferential surface involves a rough machining process in which the inner circumferential surface is cut to a predetermined inner diameter dimension, and a cutting process in which the apex of a cutting tip with an apex angle of 90° or less is cut. A finish that forms a groove or R surface on the inner circumferential surface by applying the corner to the inner circumferential surface in a direction such that the bisector of the apex angle is perpendicular to the ring axis direction and cutting along the circumferential direction. A method for manufacturing a ring, comprising a processing step. A process of punching out a washer-shaped ring material from a plate of precious metal, a drawing process of forming the ring material into a substantially cylindrical ring, a rolling process of sandwiching the ring between inner and outer sides with rollers, and rolling. The cutting process involves cutting the end face, outer circumferential surface, and inner circumferential surface of the ring, and the cutting of the inner circumferential surface involves a rough machining process in which the inner circumferential surface is cut to a predetermined inner diameter dimension, and the apex corner of a cutting tip with an apex angle of 90° or less. The finishing process involves forming a rounded surface on the inner peripheral surface by applying it to the inner peripheral surface in a direction perpendicular to the axial direction of the ring and cutting it along the circumferential direction. The machining process is characterized by dividing the inner peripheral surface into a left half region and a right half region, and cutting each region while moving the cutting edge in one direction, either toward or away from the ring. How to make rings . A process of punching out washer-shaped ring materials from plates of different types of precious metals, and a process of stacking multiple sheets of washer-shaped ring materials made of different types of precious metals and joining them by hot pressing to form a substantially cylindrical ring. and a cutting process to cut the end face, outer circumferential surface, and inner circumferential surface of the ring, and the cutting of the inner circumferential surface involves a rough machining process in which the inner circumferential surface is cut to a predetermined inner diameter dimension, and a cutting process in which the apex of a cutting tip with an apex angle of 90° or less is cut. It has a finishing process that forms a rounded surface on the inner peripheral surface by applying the corner to the inner peripheral surface in a direction perpendicular to the ring's axis and cutting along the circumferential direction. The finishing process is characterized by dividing the inner peripheral surface into a left half region and a right half region, and cutting each region while moving the cutting edge in one direction, either toward or away from the ring. How to make a ring .

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