JP4128515B2 - Jewelry grinding equipment - Google Patents

Description

  The present invention relates to a jewelry grinding apparatus for finishing a diamond outer surface.

  Gemstones such as diamond, ruby, and sapphire are finished from gemstones through various processing steps to gems with cut structures. The beauty of jewels can be said to depend on the cut structure, and the value of the jewels is enhanced by the precise processing.

  For example, when diamond is described as a representative example of gemstones, diamond is a single crystal of carbon belonging to the equiaxed system. The rough diamonds are mostly produced in a deformed or deformed form, and the rough diamonds themselves are just crystals that are dull and rarely shine. However, when a rough surface is cut by grinding or polishing the rough, light incident from the cut surface is reflected to produce a beautiful glossy shine. The value of diamond as a gemstone is said to have been created only by the establishment of processing technology.

  Various cuts and trials have been carried out on the cut structure that maximizes the brightness of the diamond, and since the mathematician Marcel Turkey Fusky mathematically proved the ideally cut in 1919 that reflects light to the highest degree, The diamond is processed into a cut structure (hereinafter referred to as a brilliant cut) in which the angle and ratio of each part are defined in accordance with this ideal cut.

  FIG. 8 shows a brilliant cut of diamond. Each part of the brilliant cut is given the following name. In other words, it is roughly divided into an upper crown 1 and a lower pavilion 2, and the periphery of the boundary between the crown 1 and the pavilion 2 is called a girdle 3. The ceiling surface of the crown 1 is called a table 4, the slope of the crown 1 is called a bezel 5, and the apex of the pavilion 2 is called a curette 6.

  Such a brilliant-cut diamond has a 58-hedron cut, and the dimensional ratio of each part such as the crown 1, the pavilion 2, and the table 4 is strictly defined. Whether or not to maximize the brightness of the diamond depends on the processing technology to make the diamond brilliant cut exactly as designed.

While diamond values are pursued as gemstones, diamonds are widely used in tools because of their unparalleled hardness. In the field of industrial diamond, gem value is not a problem, and processing is easy. Various machine tools for polishing the R portion of diamond tools and cemented carbide tools have been invented (for example, patents). Reference 1).
JP-A-2-224961

  Conventionally, diamond processing is carried out by pressing diamonds against a grinding wheel that is manually rotated by highly skilled craftsmen and relying on intuition and experience.

  Therefore, if the symmetry of the cut surface of the brilliant cut is slightly out of order, light leaks from the pavilion 2, the brightness is reduced, and the commercial value as a jewel is greatly reduced.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a jewelry grinding apparatus capable of solving the problems of the prior art and accurately determining the cut surface of the diamond so as to finish the cut surface with high accuracy. It is in.

In order to achieve the above object, the present invention provides a disc-shaped grinding wheel, a grinding wheel rotating device having a grinding wheel shaft for rotating the grinding wheel in a horizontal plane, and a direction in which the grinding wheel is separated from and in contact with the grinding wheel in a horizontal plane. A table that moves on the bed in a direction perpendicular to the bed, a column that moves on the table in parallel with a direction that makes contact with the grinding wheel in a horizontal plane, and a saddle that is attached to the column and moves in the vertical direction. A chuck means for holding a diamond having a polyhedral cut structure by a collet press-fitting method using a diamond girdle, and an indexing means for mechanically indexing the cut surface of the diamond connected to the chuck means and held by the chuck means; , And a revolving shaft that rotatably supports the work holding shaft about an axis parallel to the moving direction of the table. Cutting surface angle setting means for setting the angle of the diamond cutting surface with respect to the grinding surface of the grinding wheel, and the chuck means holds the diamond at the girdle portion so that the rotational symmetry axis of the diamond is coaxial. It consists of the collet to hold | grip and the holder externally fitted to the said collet.

  According to the present invention, the cut surface of diamond as a gemstone can be accurately determined, and the cut surface can be finished with high accuracy, and it can be efficiently replaced continuously by numerical control instead of skilled craftsmanship. Can be precisely ground as designed.

Hereinafter, an embodiment of a jewelry grinding apparatus according to the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a side view of the jewelry grinding apparatus according to the present embodiment, and FIG. 2 is a plan view of the jewelry grinding apparatus. 1 and 2, reference numeral 10 indicates the entire jewelry grinding apparatus. Reference numeral 12 indicates a bed. The jewelry grinding apparatus 10 of this embodiment includes a table 14, a column 15, a saddle 16, a work holding shaft 18, a grindstone rotating apparatus 20, and the like.

A grindstone rotating device 20 and a table base 21 are installed on the upper surface of the bed 12. The grinding wheel rotating device 20 includes a grinding wheel 22. In the jewelry grinding apparatus 10 of this embodiment, the direction toward or away from the grinding wheel 22 with respect to the grinding wheel 22 is the direction of the Z axis and the direction orthogonal to the direction of the Z axis, and the grinding wheel. The direction parallel to 22 is the X axis, and the vertical direction is the Y axis.

  X-axis guides 23a and 23b extending in parallel with the X-axis direction are laid on the upper surface of the table base 21, and the table 14 can be guided and moved by the X-axis guides 23a and 23b. On the table 14, Z-axis guides 24a and 24b extending in parallel with the Z-axis direction are laid, and the column 15 installed on the table 14 moves along the Z-axis guides 24a and 24b. It has become. A saddle 16 is attached to the front of the column 15 via Y-axis guides 25a and 25b so as to be movable in the vertical direction. Reference numeral 26 indicates an X-axis servo motor that drives a ball screw mechanism that feeds the table 14, reference numeral 27 indicates a Z-axis servo motor that drives the ball screw mechanism that feeds the column 15, and reference numeral 28 indicates the saddle 16. This is a Y-axis servo motor that drives a ball screw mechanism to be fed.

  The saddle 16 is provided with a work holding shaft 18 having a chuck portion 30 for holding diamond to be ground. Next, the work holding shaft 18 will be described.

FIG. 3 is a view showing a side surface of the work holding shaft 18, and FIG. 4 is a view showing a cross section of the turning shaft portion of the work holding shaft 18.
A diamond is denoted by reference numeral 60 as a workpiece to be ground. The diamond 60 is detachably held at the tip of the chuck portion 30. The chuck portion 30 is coaxially connected to a Kirbic coupling 32 (registered trademark of US Gleason Co., Ltd.) constituting indexing means for indexing the cut surface of the diamond 60. The Kirvic coupling 32 can be divided into 360 degrees and divided into 32 parts.

  As shown in FIG. 4, the Kirvic coupling 32 includes a first coupling member 61 and a second coupling member 62, and the first coupling member 61 and the second coupling member 62 are respectively radial. A large number of teeth 63 extending in the direction are provided, and the teeth 63 mesh with each other through the teeth 63. The first coupling member 61 is fastened with a bolt to the chuck portion 30 constituting the work holding shaft 18.

On the other hand, an air cylinder 65 is coaxially provided on the second coupling member 62. A piston rod 67 extending from the piston 66 of the air cylinder 65 is connected to the first coupling member 61. A disc spring 68 is housed inside the air cylinder 65, and the piston 66 is pushed up by the elastic force of the disc spring 68, so that the first coupling member 61 connected to the piston rod 67 is actuated by the disc spring 68. And is engaged with the second coupling member 62. Air is supplied from the port 70 to the cylinder chamber 69 of the air cylinder 65. When air is introduced into the cylinder chamber 69, the piston 66 is pushed down against the elastic force of the disc spring 68, the meshing between the first coupling member 61 and the second coupling member 62 is released, and the second cup The entire structure including the lower chuck portion is rotated from the ring 62. Therefore, at this time, the chuck portion 30 can be manually indexed.

  The chuck portion 30 includes a collet 70 and a cylindrical holder 72 that is coaxially fitted on the collet 70. The collet 70 has a slit structure extending in the axial direction. As shown in FIG. 5, the inner diameter of the tip of the collet 70 is substantially equal to the diameter of the girdle 3 of the diamond 60. By using the girdle 3, the diamond 60 is coaxially fitted to the tip of the collet 70. Can be made.

A press-fitting method is employed for holding the diamond 60. Using the collet press fit special tool, press-fitting the collet 70 to the holder 7 2. As a result, the tapered portion at the tip of the collet 70 is contracted, and the diamond 60 is firmly held at the tip of the collet 70.

  In FIG. 4, reference numeral 34 indicates a turning axis of the work holding shaft 18, and this turning axis 34 is parallel to the direction of the X axis. A bracket 35 is attached to the saddle 16, and a support block 36 is fixed to the bracket 35. A bearing 37 is attached to the inside of the support block 36, and the pivot shaft 34 is rotatably supported by the bearing 37. A U-shaped joint member 38 is attached to the pivot shaft 34, and the upper end portion of the cylinder 65 is fixed to the joint member 38. Therefore, the work holding shaft 18 constituted by the joint member 38, the cylinder 65, the carbide coupling 32, and the chuck portion 30 can be swung in the YZ plane around the swivel shaft 34 as a unit.

  In this embodiment, a clamper 46 for manually turning the work holding shaft 18 to lock the turning angle to an arbitrary angle is provided. By tightening the clamper 46, the clamp plate 45 integral with the joint member 38 can be fixed. The clamp plate 45 is formed with a long groove 47 into which the shaft of the clamper 46 is loosely fitted. When the clamper 46 is loosened, the workpiece holding shaft 18 is allowed to turn.

Next, in FIG. 4, reference numeral 40 indicates a servo motor connected to the turning shaft 34. The servo motor 40 is a servo motor having a built-in rotary encoder. In this embodiment, instead of being used for driving the pivot shaft 34, a means for setting the angle of the cut surface of the diamond 60 is configured. Used as an element. The main body of the servo motor 40 is attached to a frame 41 fixed to the support block 36, and the rotation shaft 40 a of the servo motor is connected to the turning shaft 34 via a joint 39. Accordingly, when the entire workpiece holding shaft 18 is turned, the rotation shaft 40a of the servo motor 40 is rotated together with the rotation of the turning shaft 34, and the rotation angle is detected by counting the pulses output from the built-in rotary encoder. be able to. Further, by tightening the clamper 46, the turning angle of the workpiece holding shaft 18 can be fixed.
Next, the grindstone rotating device 20 will be described with reference to FIGS. 1 and 2.

  The disc-shaped grinding wheel 22 has a grinding wheel shaft 42 coaxially connected thereto, and when the grinding wheel shaft 42 rotates, the grinding wheel 22 can rotate in a horizontal plane (XZ plane). As shown in FIG. 2, an annular grindstone 43 is fixed to the upper surface of the grinding wheel 22. This grindstone 43 is mixed with diamond powder. A driving mechanism for the grindstone shaft 42 is provided inside the case 44.

  In FIG. 1, reference numeral 50 indicates a numerical controller. In this embodiment, the jewelry grinding apparatus 10 is configured as a numerically controlled machine tool for three-axis control of the X axis, the Y axis, and the Z axis.

  The numerical controller 50 sends a command calculated by analyzing a machining program related to diamond grinding to the servo drive unit 52. The servo drive unit 52, based on the command, sends an X-axis servo motor 26, a Z-axis servo motor. 27, controls the Y-axis servomotor 28. The control loop for feedback control of the position and the like is not shown.

  In this embodiment, the work holding shaft 18 is swung manually around the swivel axis 34. For convenience, the swivel movement axis is denoted as the A axis. The rotary encoder built in the servo motor 40 sends a pulse signal proportional to the turning angle of the workpiece holding shaft 18 to the numerical control device 50, and the turning angle is calculated based on the pulse signal at this time. It is displayed on the display unit 54. In this embodiment, the A-axis is manually turned, but it is also possible to make it automatic without using manual operation.

  The jewelry grinding apparatus according to the present embodiment is configured as described above. Next, the effect of the jewelry grinding apparatus 10 will be described by taking the processing of a diamond cut surface as an example.

  In this embodiment, in order to perform grinding by numerical control by making good use of the structural features of the brilliant cut of diamond, first, each cut surface to be ground of the brilliant cut of diamond will be described.

  The diamond 60 to be ground is the brilliant cut diamond of 58 facet cut shown in FIG. FIG. 9 is a plan view of the brilliant cut as seen from the crown 1, and FIG. 10 is a plan view of the brilliant cut of diamond as seen from the pavilion 2.

  In the brilliant cut of diamond, the axis passing through the curette 6 from the center of the table 4 is a rotationally symmetric axis 100. The crown 1 has 32 cut surfaces, the pavilion 2 has 24 cut surfaces, the table 4 has 1 cut surface, and the curette 6 has 1 cut surface, for a total of 58 surfaces.

  As shown in FIG. 9, the cut surface of the brilliant-cut crown 1 is made up of four types of cut surfaces: a cut surface a, a cut surface b, a cut surface c, and a cut surface d, as distinguished from its shape and arrangement. I understand that. Among them, the cut surfaces a are arranged on the outer periphery of the crown 1 and there are eight planes symmetrically by 45 ° with respect to the rotational symmetry axis 100. There are eight cut surfaces b symmetrically with respect to the rotational symmetry axis 100 by 45 ° so as to be adjacent to the cut surface a. The cut surface c has eight surfaces of 45 ° with respect to the rotational symmetry axis 100 between the cut surface a and the cut surface b. The cut surface d has eight surfaces of 45 ° with respect to the rotational symmetry axis 100 between the adjacent cut surfaces c. Therefore, the cut surface of the brilliant-cut crown 1 can be determined by turning the rotational symmetry axis 100 by 1/8 for each type of the cut surfaces a to d.

  Next, in FIG. 10, regarding the cut surface of the brilliant-cut pavilion 2, the pavilion 2 includes three types of cut surfaces e, g, f, and g. Each of the eight planes is symmetric about 45 ° with respect to the rotational symmetry axis 100. Therefore, the cut surface of the pavilion 2 can also be determined by rotating the rotational symmetry axis 100 by 1/8 for each type.

  Therefore, in the jewelry grinding apparatus of the present embodiment, each cut surface of the pavilion 2 can be ground as follows.

  First, as shown in FIG. 3, the diamond 60 that is a workpiece is held at the tip of the chuck portion 30 so that the rotational symmetry axis 100 coincides with the center line of the Kirvic coupling 32.

Next, the position for grinding the diamond 60 on the X, Y, and Z axes in the jewelry grinding apparatus of the present embodiment will be described.
In FIG. 4, the table 14 moves in the X axis and is positioned at a position where the center of the workpiece holding shaft 18 in the X axis direction coincides with the center of the grinding wheel shaft 42 of the grinding wheel 22.

  The column 15 moves on the table 14 in the Z-axis until the specific cut surface of the diamond 60 to be ground becomes parallel to the surface of the grinding wheel 43 on the grinding wheel 22 as shown in FIG. In a state where the workpiece holding shaft 18 is turned, for example, the Z-axis coordinate of the diamond 60 is positioned at a position where it coincides with the Z-axis coordinate at the center of the width of the grindstone 43.

  Here, in the grinding of the pavilion 2 of the diamond 60 (the same applies to the cut surfaces a to d of the crown 1), in FIG. 7, when the cut surface e is ground and when the cut surface f is ground, the cutting is performed. The turning angle θ of the work holding shaft 18 when the cut surfaces e to g are made parallel to the surface of the grindstone 43 differs depending on whether the surface g is ground (in this specification, according to the diamond cut surface). Matching the turning angle of the workpiece holding shaft 18 is defined as setting the cut surface angle).

  Therefore, if the turning angle θ of the workpiece holding shaft 18 changes depending on which of the cut surfaces e to g is to be ground, the position of the diamond 60 on the Z axis naturally changes. Based on the design data of 60 brilliant cuts, the turning angle θ and the position on the Z-axis are calculated for each cut surface.

  The saddle 16 moves along the column 15 in the Y-axis direction, and is positioned at a predetermined standby position on the Y-axis before starting grinding in FIG.

  In addition to the coordinates of the grinding position of the diamond 60 as described above, the data necessary for numerical control of the grinding of the diamond 60 are mainly the cutting amount Δy in the Y-axis direction, and the surface of the grindstone 22 in the width direction. The amount of movement ΔZ in the Z-axis direction for reciprocating is set in advance.

  Then, a machining program is created using numerical data necessary for grinding the pavilion 2 of the diamond 60, and the machining program is executed by the numerical controller 50, whereby the grinding of the pavilion 2 of the diamond 60 is semi-automatically performed as follows. Can be done.

  In this embodiment, in each of the cut surfaces e to g of the pavilion 2 of the diamond 60, all the eight cut surfaces e are ground first, and then the cut surface f and the cut surface g are advanced in this order.

  Therefore, when the grinding of the cut surface e is started, the turning angle θ of the workpiece holding shaft 18 is adjusted in accordance with the cut surface e of the pavilion 2 prior to execution of the machining program. This angle setting can be performed as follows.

  First, the clamper 46 is loosened and the workpiece holding shaft 18 is kept in an unclamped state. When the work holding shaft 18 is turned by manual operation, a pulse signal output from a rotary encoder (not shown) provided in the servo motor 40 is taken into the numerical controller 50 and the turning angle is displayed on the display 54 in real time. The While confirming with this indicator 54, the turning angle θ of the workpiece holding shaft 18 is adjusted so that the first cut surface e of the cut surfaces f of the pavilion 2 is parallel to the surface of the grindstone 43, and the clamper 46 is tightened. The cut surface angle is set by locking.

  When the machining program is executed, the table 14, the column 15, and the saddle 16 are moved under the control of the numerical controller 50. As described above, the diamond 60 at the tip of the work holding shaft 18 is in the grinding standby position shown in FIG. Is positioned. Further, the grindstone rotating device 20 is also activated at the same time, and the grindstone wheel 22 starts rotating at a predetermined number of revolutions.

  Next, the saddle 16 is moved down by the Y-axis movement until the cut surface e of the diamond 60 held by the chuck portion 30 of the workpiece holding shaft 18 contacts the grindstone 43. When the column 15 reciprocates a distance of ΔZ by moving the Z axis while maintaining the Y axis position, the diamond 60 reciprocates in the width direction of the grindstone 43 while the cut surface e is in contact with the surface of the grindstone 43. . Furthermore, the cut surface e of the first surface can be ground by lowering the saddle 16 by a slight cutting amount Δy while continuing this reciprocation. Depending on the grinding resistance, the width direction of the grindstone 43 may be moved in an arbitrary direction on the XZ plane.

  When the grinding of the cut surface e of the first surface is thus completed, the workpiece holding shaft 18 rises to the standby position together with the saddle 16, and the diamond 60 escapes from the grindstone 43.

  Thereafter, when air is supplied to the cylinder 65 of the Kirbic coupling 32, the first coupling member 61 and the second coupling member 62 are disengaged. Therefore, the chuck unit 30 is switched to a state where it can be manually indexed. If it is rotated by 1/8 rotation, the surface of the next cut surface e after the ground surface is parallel to the surface of the grindstone 43, and the cut surface can be indexed. If the air coupling is turned off and the carbide coupling 32 is fixed, grinding can be performed by repeating the same operation as the first cut surface. The above operation may be repeated for all the eight cut surfaces e.

  When the grinding of all eight cut surfaces e of the diamond 60 is completed in this way, the workpiece holding shaft 18 is raised to the standby position together with the saddle 16 again. Then, while turning the workpiece holding shaft 18 by manual operation, while checking the turning angle with the indicator 52, the workpiece is held so that the first surface of the cut surface f of the pavilion 2 is parallel to the surface of the grindstone 22. The turning angle θ of the shaft 18 is adjusted in advance. Hereinafter, as in the case of the cut surface e, grinding and cut surface indexing may be repeated for all eight cut surfaces f.

  The same applies to the grinding of the remaining cut surface g in the pavilion 2 of the diamond 60, and the description is omitted to avoid repeated description. Further, with respect to each of the cut surfaces a to d of the crown 1 of the diamond 60, the diamond 60 is held in the direction opposite to FIG. 7 so that the crown 1 protrudes from the tip of the chuck portion 30 of the workpiece holding shaft 18. Grinding can be done in exactly the same way.

  In the brilliant cut of the diamond 60, the table 4 has only one cut surface, and this cut surface is perpendicular to the rotational symmetry axis 100. Therefore, if the workpiece holding shaft 18 is fixed perpendicularly to the surface of the grindstone 22 after the grinding of all the cut surfaces of the crown 1 is completed, grinding can be performed without the need for indexing.

  As described above, according to the present embodiment, since the diamond 60 is held by the press-fitting method using the girdle 3 at the tip of the collet 70, the rotationally symmetric axis 100 can be reliably held so as not to shift. While accurately determining each brilliant cut surface of diamond, it is possible to substitute a skilled craftsman's skill for continuous and efficient grinding by numerical control and precisely as designed. Further, it is possible to obtain a fully automatic jewelry grinding apparatus by automating the indexing means for indexing the diamond cut surface.

The side view of the jewelry grinding device by one embodiment of the present invention. The top view of the jewelry grinding device. The side view which shows the workpiece | work holding shaft with which the jewelry grinding apparatus by one Embodiment of this invention is provided. The partially notched side view which shows the turning axis | shaft part of the workpiece holding shaft. Sectional drawing which shows the principal part of the chuck | zipper part of the workpiece holding shaft. FIG. 3 is a side view of the workpiece holding shaft in a state where the workpiece holding shaft is turned on standby for grinding. Explanatory drawing which shows grinding of the brilliant cut of the diamond by the jewelry grinding apparatus by this invention. Explanatory drawing of brilliant cut of diamond. A plan view of a brilliant diamond cut from the crown. The top view which looked at the brilliant cut of diamond from the direction of the pavilion.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Crown 2 Pavilion 3 Girdle 5 Bezel 6 Curette 12 Bed 14 Table 15 Column 16 Saddle 18 Work holding shaft 20 Grinding wheel rotating device 22 Grinding wheel 26 X-axis servo motor 27 Z-axis servo motor 28 Y-axis servo motor 30 Chuck part 32 Car Big coupling (indexing means)
34 Rotating shaft 40 A-axis servo motor 42 Grinding wheel shaft 60 Workpiece (diamond)
70 collet 72 holder 100 axis of rotational symmetry

Claims (4)

A disk-shaped grinding wheel, and a grinding wheel rotating device having a grinding wheel shaft for rotating the grinding wheel in a horizontal plane;
A table that moves on the bed in a direction perpendicular to the direction of separating with respect to the grinding wheel in a horizontal plane;
A column that moves on the table in parallel with a direction in which the grinding wheel is separated from and connected to the grinding wheel;
A saddle attached to the column and moving vertically;
Chuck means for holding a diamond having a polyhedral cut structure by a collet press-fitting method using a diamond girdle; and indexing means for mechanically indexing the cut surface of the diamond connected to the chuck means and held by the chuck means; A workpiece holding shaft having
A cutting surface angle setting means for setting a diamond cutting surface angle with respect to the grinding surface of the grinding wheel, having a turning shaft that supports the workpiece holding shaft so as to be turnable about an axis parallel to a moving direction of the table; Equipped,
The chuck means includes
A collet that grips the diamond at the girdle portion so that the rotational symmetry axis of the diamond is coaxial;
A jewelry grinding apparatus comprising: a holder fitted on the collet. 2. The jewelry grinding apparatus according to claim 1, wherein the indexing unit includes a Kirbic coupling capable of indexing an integral multiple of 32 divisions of 360 ° as a unit.   The axis for moving the table is the X axis, the axis for moving the column is the Z axis, the axis for moving the saddle is the Y axis, and is configured as a numerically controlled machine tool for three-axis control of the X, Y, and Z axes The jewelry grinding apparatus according to claim 1, wherein:   2. The jewelry grinding apparatus according to claim 1, wherein the cut surface angle setting means includes means for detecting detection of an angle of the cut surface and means for fixing the angle of the set cut surface. .

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