JP2005125442A - Diamond working method and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently and precisely grind the whole cut surfaces of diamond, by using a numerically controlled machine. <P>SOLUTION: A girdle 3 is ground by a grinding wheel 18 while rotating a work holding shaft 54 by coaxially holding the diamond 100 with a table 4 as a reference between a work shaft 14 and a tail stock spindle 30, by using a first processing apparatus 10 having the work shaft 14 and the tail stock shaft 14, by setting the table 4 of the roughly processed diamond 100 as a temporary reference surface of processing. Afterwards, the diamond 100 is held by the work holding shaft 58 so that its rotational symmetry axis becomes coaxial, by using a second processing apparatus 50 having an indexing means 62 on the work holding shaft 58. The table 4 is finally finished by grinding the cut surface by a grinding wheel 83, while indexing the respective cut surfaces of a pavilion 2 and a crown 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a diamond processing method and apparatus, and more particularly to a diamond processing method and apparatus for finishing the outer surface of diamond used for jewelry.

  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.

  Thus, FIG. 11 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 precisely brilliant cut as designed. If the symmetry of the cut surface of the brilliant cut is slightly out of order, Leakage will decrease and the shine will decrease, and the commercial value of jewelry will be greatly reduced.

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

  However, in the field of dealing with diamonds that pursue value as gems, unlike diamonds as industrial products, labor concentration that the diamond processing industry has historically been established in certain parts of the world (Israel, India, etc.) In addition to the special circumstances of a traditional industry, the idea that processing by highly skilled craftsmen produces high-value gems has permeated.

  Therefore, in the conventional diamond finishing process, the craftsman carefully checks the shape using a magnifying glass, etc., and grinds the roughly processed diamond against the grindstone, so the processing efficiency remains low. is the current situation.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-described problems of the prior art and to use a NC machine to efficiently grind all cut surfaces of the diamond. Is to provide.

  To achieve the above object, the present invention provides a diamond processing method for grinding a polyhedral cut diamond comprising a crown, a pavilion, a table, and a girdle as a constituent part. The diamond is set coaxially with respect to the table between the workpiece holding shaft and the tailstock shaft using a first processing device that is set as a temporary reference surface for processing and has a workpiece holding shaft and a tailstock shaft. A first grinding step of grinding the girdle with a grindstone while rotating the workpiece axis, and a second machining apparatus having an indexing means on the workpiece axis, so that the rotational axis of the diamond is coaxial. 2nd grinder that finishes the table by grinding the cut surface with a grindstone while indexing each cut surface of the pavilion and crown When it is characterized in that it consists of.

  Further, the present invention is a diamond processing apparatus for finishing a diamond having a polyhedral cut structure including a crown, a pavilion, a table, and a girdle by grinding, and has a cup-shaped grindstone that moves on the bed in the Z-axis direction. A first processing apparatus for grinding a diamond girdle, comprising: a grindstone rotating apparatus; a work shaft rotating apparatus that includes a tailstock having a tailstock opposed to the work axis and moves on the bed in the X-axis direction; A disk-shaped grinding wheel, a grinding wheel rotating device having a grinding wheel shaft that rotates the grinding wheel in a horizontal plane, an X-axis table that moves on the bed in the X-axis direction, and a movement on the X-axis table in the Z-axis direction Column, a saddle that moves in the vertical Y-axis direction along the column guide, and indexing means for indexing the diamond cut surface held by the chuck portion. And a work holding shaft which is mounted via a pivot axis A-axis on the saddle, diamond crown, and a second processing device for grinding the pavilion and the table, characterized in that it consists of.

  As is clear from the above description, according to the present invention, all the brilliant cut surfaces of the diamond are accurately ordered in order by first grinding the girdle using the rough diamond table as a temporary reference surface. Can be ground efficiently.

Hereinafter, an embodiment of a diamond processing method and apparatus according to the present invention will be described with reference to the accompanying drawings.
The diamond processing apparatus according to the present embodiment includes a first processing apparatus shown in FIG. 1 and a second processing apparatus shown in FIG. First, the first processing apparatus will be described with reference to FIGS.

  An X-axis table 12 that moves along the X-axis is provided on the bed 11 of the first processing apparatus 10, and the Z-axis is perpendicular to the X-axis (perpendicular to the drawing) along the Z-axis. A Z-axis table 13 that moves is arranged. The X axis table 12 is provided with a work axis rotating device 16 that rotates a work axis 14 that rotates about an A axis parallel to the X axis, and a tailstock 29. A grindstone rotating device 20 that rotates a cup-shaped grindstone 18 is provided on the Z-axis table 13. Reference numeral 21 is a numerical controller.

  An X-axis servomotor 23 that drives the X-axis feed mechanism is disposed at the end of the X-axis base 22. Reference numeral 24 denotes an A-axis servomotor that drives the work shaft 14. In FIG. 1, reference numeral 25 denotes a ball screw of a Z-axis feed mechanism that feeds the Z-axis table 13, and this ball screw 25 is driven by a Z-axis servomotor arranged on the opposite side not shown in FIG. Driven.

  Next, in FIG. 2, a tailstock base 27 is connected via a bracket 26 to the work shaft rotating device 16 that drives the work shaft 14. A tailstock 29 is disposed on the tailstock base 27 so as to be movable in the A-axis direction via a guide 27a. A tailstock 30 is attached to the tailstock 29 concentrically so as to face the work shaft 14. Reference numeral 31 indicates a pressing mechanism that biases the tailstock 29 in order to hold the diamond 100 that is a workpiece between the workpiece shaft 14 and the tailstock 30. The pressing mechanism 31 is a combination of a coil spring and an air cylinder. The tailstock 29 is constantly pressed against the work shaft 14 by the coil spring, and the air cylinder is operated to adjust the pressure of the air to increase the pressing force. It can be adjusted. As shown in FIG. 3, a receiving groove 14 a that is recessed in a substantially conical shape is formed concentrically on the end surface of the work shaft 14.

  Further, the tailstock base 27 is provided with a switching lever 28, and when the switching lever 28 is rotated in the clockwise direction, the tailstock 29 can be moved away from the work shaft 14. Further, when the switching lever 28 is turned counterclockwise, the tailstock 29 can be moved toward the work shaft 16.

  The grindstone 18 is a cup-shaped grindstone mixed with fine diamond powder. The end surface of the grindstone 18 is a grindstone surface 32. The axis of the grindstone surface 32 is parallel to the Z axis, and the grindstone surface 32 rotates in the vertical plane. In FIG. 2, the inner diameter of the grindstone 18 is longer than the length in the A-axis direction from the tip of the tailstock 30 to the rear end of the tailstock 29, and the tailstock is positioned at a position corresponding to the hollow portion 33 of the grindstone 18. A table 29 can be arranged. Therefore, the tailstock 29 can be placed in the hollow portion 33 of the grindstone 18 so that the tailstock 29 and the grindstone surface 32 of the grindstone 18 do not interfere with each other.

  Next, the second processing apparatus constituting the diamond processing apparatus according to the present embodiment will be described. FIG. 4 is a side view of the second processing apparatus, and FIG. 5 is a plan view of the second processing apparatus. 4 and 5, reference numeral 50 indicates the entire second processing apparatus. Reference numeral 52 indicates a bed. The processing device 50 includes an X-axis table 54, a column 55, a saddle 56, a work holding shaft 58, a grindstone rotating device 60, and the like.

  A grindstone rotating device 60 and a table base 61 are installed on the upper surface of the bed 52. The grinding wheel rotating device 60 includes a grinding wheel 62. In this processing device 50, the direction toward or away from the grinding wheel 62 with respect to the grinding wheel 62 is the direction of the Z axis, and the direction perpendicular to the direction of the Z axis is parallel to the grinding wheel 62. The direction to do is the X axis, and the vertical direction is the Y axis.

  X-axis guides 63a and 63b extending in parallel with the X-axis direction are laid on the upper surface of the table base 61, and the X-axis table 54 can be guided and moved by the X-axis guides 63a and 63b. On the X-axis table 54, Z-axis guides 64a and 64b extending in parallel with the Z-axis direction are laid, and a column 55 installed on the X-axis table 54 extends along the Z-axis guides 24a and 24b. To move. A saddle 56 is attached to the front surface of the column 55 via Y-axis guides 65a and 65b so as to be movable in the vertical direction. Reference numeral 66 indicates an X-axis servo motor that drives a ball screw mechanism that sends the X-axis table 54, reference numeral 67 indicates a Z-axis servo motor that drives the ball screw mechanism that sends the column 55, and reference numeral 68 indicates This is a Y-axis servomotor that drives a ball screw mechanism that feeds the saddle 56.

  A work holding shaft 58 having a chuck portion 70 for holding the diamond 100 as a work to be ground is attached to the saddle 56. Next, the work holding shaft 58 will be described.

FIG. 6 is a view showing a side surface of the work holding shaft 58, and FIG. 7 is a view showing a cross section of the turning shaft portion of the work holding shaft 58.
The diamond 100 that is a workpiece is detachably held at the tip of the chuck portion 70. The chuck portion 70 is coaxially coupled to a Kirbic coupling 72 (registered trademark of US Gleason Corporation) that constitutes an indexing means for indexing the cut surface of the diamond 100. The Kirvic coupling 72 can be determined by dividing 360 degrees around 32 degrees. As shown in FIG. 7, when the air cylinder 73 is supplied with air and the piston 73a is lowered, the carbic coupling 72 is released from the clamp and moves the chuck part 70 together with the lower half of the carbic coupling 72 1/32 times. It can be manually determined every time. The diamond 100 is firmly held at the tip of the chuck portion 70. The diamond 100 is held by a press-fitting method.

  6 and 7, reference numeral 74 indicates a turning axis of the work holding shaft 58, and this turning axis 74 is parallel to the direction of the X axis. A bracket 75 is attached to the saddle 56, and a support block 76 is fixed to the bracket 75. A bearing 77 is attached to the inside of the support block 76, and the pivot shaft 74 is rotatably supported by the bearing 77. A U-shaped joint member 78 is attached to the turning shaft 74, and the upper end portion of the cylinder 73 is fixed to the joint member 78. Therefore, the work holding shaft 58 constituted by the joint member 78, the air cylinder 73, the carbide coupling 72, and the chuck portion 70 can be swung in the YZ plane around the swivel shaft 74 as a unit. . The control axis of this turning motion is the A axis.

  In FIG. 7, reference numeral 80 indicates an A-axis servomotor connected to the turning shaft 74. The main body of the A-axis servo motor 80 incorporating this rotary encoder is attached to the frame 71 fixed to the support block 76, and the rotation shaft 80 a of the A-axis servo motor 80 is connected to the turning shaft 74 via a joint 79. It is connected with. The work holding shaft 58 can be turned by manual operation, and reference numeral 86 indicates a clamper for fixing the turning angle during manual operation.

Next, the grindstone rotating device 60 will be described with reference to FIGS.
The disc-shaped grinding wheel 62 has a grinding wheel shaft 82 connected coaxially, and when the grinding wheel shaft 82 rotates, the grinding wheel 62 can rotate in a horizontal plane (XZ plane). As shown in FIG. 2, an annular grinding wheel 83 is fixed to the upper surface of the grinding wheel 62. The grindstone 83 is mixed with diamond powder.

  In FIG. 4, reference numeral 90 indicates a numerical controller. In this embodiment, the second machining apparatus 50 is configured as a numerically controlled machine tool for four-axis control of the X axis, Y axis, Z axis, and A axis.

  The numerical controller 90 sends a command calculated by analyzing a processing program related to jewelry grinding to the servo drive unit 92. The servo drive unit 92, based on the command, sends an X-axis servo motor 66 and a Z-axis servo. The motor 67, the Y-axis servo motor 68, and the A-axis servo motor 80 are controlled. The control loop for feedback control of the position and the like is not shown. Reference numeral 94 indicates a display unit such as a monitor.

  Further, the grindstone shaft 82 of the grindstone rotating device 60 is driven by a grindstone motor 84. The grindstone motor 84 rotates at a rotational speed commanded from the numerical controller 90.

  The diamond processing apparatus according to the present embodiment is configured as described above. Next, a diamond processing method performed using the diamond processing apparatus will be described.

  In the present 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 the diamond 100 will be described.

  The diamond 100 to be ground is the brilliant-cut diamond of 58 plane cut shown in FIG. FIG. 12 is a plan view of the brilliant cut as seen from the crown 1, and FIG. 13 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 110. 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. 12, the cut surface of the brilliant-cut crown 1 consists 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 the shape and arrangement thereof. I understand that. Of these, the cut surfaces a are arranged on the outer periphery of the crown 1 and are eight symmetrically with respect to the rotational symmetry axis 110 by 45 °. There are eight cut surfaces b symmetrically with respect to the rotational symmetry axis 110 so as to be adjacent to the cut surface a by 45 °. The cut surface c has eight surfaces of 45 ° with respect to the rotational symmetry axis 110 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 110 between the adjacent cut surfaces c. Therefore, the cut surface of the brilliant-cut crown 1 can be determined by rotating the rotational symmetry axis 110 by 1/8 for each type of the cut surfaces a to d.

  Next, in FIG. 13, 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 with respect to the rotational symmetry axis 110 by 45 °. Therefore, the cut surface of the pavilion 2 can also be determined by rotating the rotational symmetry axis 110 by 1/8 for each type.

  The processing method of the present invention includes a processing step of grinding the girdle 3 and a processing step of grinding and finishing the pavilion 2, the crown 1 and the table 4 using the diamond 100 processed by rough cutting as a processing target.

  Therefore, the grinding process of the girdle 3 will be described with reference to FIGS. 2 and 3. As the diamond 100 that is a workpiece, one in which the table 4 is ground to such an accuracy that it can be used as a temporary reference surface for processing in the roughing of the previous process is used.

  First, in FIG. 2, the diamond 100 is disposed between the work shaft 14 of the work shaft rotating device 16 and the tailstock 30 of the tailstock 29. Then, the switching lever 28 is turned counterclockwise to move the tailstock 29 along the guide 27a on the tailstock base 27 toward the work shaft 14 side. As a result, the diamond 100 is sandwiched between the work shaft 14 and the tailstock shaft 30.

  As shown in FIG. 3, the flat end face 30 a of the tailstock 30 at this time abuts against the table 4 of the diamond 100, thereby making the table 4 serving as a temporary reference surface of the diamond 100 perpendicular to the tailstock 30. Can be positioned as follows. At the same time, the pavilion 2 of the diamond 100 is received in a receiving groove 14 a that is recessed in a substantially conical shape provided on the end surface of the work shaft 14, so that the rotationally symmetric axis 110 of the diamond 100 is the axis of the work shaft 14 and the tailstock shaft 30. Match the heart. Therefore, the diamond 100 can be accurately positioned using the table 4 of the diamond 100 as a temporary reference surface without any fine adjustment. Note that the pressing force of the tailstock shaft 30 can be adjusted by operating the air cylinder of the pressing mechanism 31 and adjusting the air pressure.

  Next, the workpiece shaft 14 is rotated by being driven by the A-axis servomotor 24 of the workpiece shaft rotating device 14 that is numerically controlled by a command from the control device 21. Then, the work shaft 14, the diamond 100, and the tail shaft 30 rotate together.

  Therefore, the grindstone 18 is fed by Z-axis movement, and the grindstone surface 32 of the grindstone 18 is brought into contact with the girdle 3 of the diamond 100. Further, the X axis movement of the X axis table 12 causes the diamond 100 to reciprocate a distance corresponding to the width of the grindstone surface 32. Then, the girdle 3 of the diamond 100 can be ground while using the grindstone surface 32 as a whole by feeding the grindstone 18 with a predetermined cutting amount by moving the Z axis.

  Since the tailstock 29 can enter the hollow portion 33 of the grindstone 18 during the reciprocating movement of the X axis, interference between the tailstock 29 and the grindstone 18 can be prevented. Therefore, in order to avoid interference with the grindstone 18, it is not necessary to make the work shaft 14 or the tailstock 41 elongated or to make the tailstock 30 thin, so that the diamond 100 can be stably held, and the girdle 3 of the diamond 100 Can be processed with high accuracy.

  Next, a processing step for grinding and finishing the pavilion 2, the crown 1, and the table 4 will be described. This processing step is performed as follows using the second processing apparatus 50 of FIGS. 4 to 8.

  First, as shown in FIG. 6, the diamond 100 that is a workpiece is held at the tip of the chuck portion 70 so that the rotational symmetry axis 110 coincides with the center line of the Kirvic coupling 72. In this case, since the girdle 3 of the diamond 100 is finished in the previous process, the positioning can be accurately performed.

  In FIG. 8, when the work holding shaft 58 turns, the specific cut surface of the diamond 100 to be ground becomes parallel to the surface of the grindstone 83 on the grindstone 62. Further, the table 54 moves in the X axis, and the column 55 moves in the Z axis on the table 54, whereby the position of the diamond 100 is positioned at a predetermined position on the grindstone 83.

  Here, in the grinding of the pavilion 2 of the diamond 100 (the same applies to each of the cut surfaces a to d of the crown 1), in FIG. 9, 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 58 when each of the cut surfaces e to g is parallel to the surface of the grindstone 83 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 58 is defined as setting the cut surface).

  Therefore, if the turning angle θ of the workpiece holding shaft 58 changes depending on which of the cut surfaces e to g is to be ground, the position of the diamond 100 on the Z axis naturally changes. Based on the design data of 100 brilliant cuts, the turning angle θ and the position on the Z-axis are calculated for each cut surface.

Next, the position where the diamond 100 is ground on the X axis, the Y axis, and the Z axis in the second processing apparatus 50 will be described.
Here, FIG. 10 shows an example of a grinding position on the grinding wheel 83 of the grinding wheel 62. In this embodiment, eight positions from P1 to P8 that are positioned symmetrically by 45 ° are preliminarily ground to measure the grinding resistance, and among these, positions that can be ground while being fed in a direction with a small grinding resistance are measured. Check it. Therefore, for example, when grinding is performed while feeding in the X-axis direction at the grinding position P1, it is assumed that the grinding resistance is small.

  In addition to the position for grinding the diamond 100 as described above, the data necessary for numerical control of the grinding of the diamond 100 are mainly the amount of cut Δy in the Y-axis direction and the surface of the grindstone 83 in the width direction. A machining program is created using numerical data such as the amount of movement in the X-axis direction to be reciprocated, the feed speed thereof, and the rotational speed of the grinding wheel 62, and this machining program is executed by the numerical controller 90 as follows. Grinding of the pavilion 2 of the diamond 100 can be performed semi-automatically.

  In this embodiment, in each of the cut surfaces e to g of the pavilion 2 of the diamond 100, 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.

  First, when the machining program is executed, controlled by the numerical controller 90, the A-axis servo motor 80 is first activated, and the workpiece holding shaft 58 turns until the turning angle θ matches the command value. Settings are made. Thereafter, this turning angle is maintained. Further, the table 54, the column 55, and the saddle 56 move, and as described above, the diamond 100 at the tip of the work holding shaft 58 is positioned at the grinding standby position above the center of the grindstone 83 shown in FIG. Furthermore, the grindstone rotating device 60 is also activated at the same time, and the grindstone wheel 62 starts rotating at a predetermined number of revolutions.

  Next, the saddle 56 is moved down by the Y-axis movement to a position where the cut surface e of the diamond 100 held by the chuck portion 70 of the workpiece holding shaft 58 is ground by the grindstone 83. Then, feeding by the following X-axis movement is performed.

  In FIG. 10, the grinding wheel 62 is rotating during the grinding process, and the diamond 100 is positioned on the machine coordinate system so as to cross the width of the grinding wheel 83 in the X-axis direction, that is, in the radial direction of the grinding wheel 62. ) To and from position (i). Then, while the diamond 100 reciprocates once, grinding is performed by instructing the rotation speed of the grinding wheel 62 and the feed speed of the diamond 100 by the numerical control device 90 so that the entire surface of the grindstone 83 hits the diamond 100. Such rotation speed and feed speed vary depending on the surface area of the grindstone 83 and the area of the cut surface of the diamond 100. Therefore, trial grinding is performed in advance to optimize the rotation speed and feed speed. Find the value.

  Thereafter, the diamond 100 reciprocates in the X-axis direction so that the cut surface e contacts the surface of the grindstone 83 and crosses the grindstone 83 in the width direction, and the entire surface of the grindstone 83 touches the diamond 100 during one reciprocation. become. Then, the cut surface e of the first surface can be ground by lowering the saddle 56 by a minute cutting amount Δy while continuing this reciprocation.

  Since the feed in the X-axis direction as described above corresponds to a feed direction with a small grinding resistance, the grinding efficiency can be increased. In addition, since the diamond 100 comes into contact with the grinding wheel 83 of the grinding wheel 62 uniformly, it is possible to prevent a decrease in accuracy due to the reduction of the piece and the reduction of the piece.

  In FIG. 10, when trial grinding at the grinding position P4 reveals that this is the direction in which the grinding resistance is small, the composite feed of the Z axis and the X axis causes the outer side from the position (j ′) inside the grindstone 83 to move outward. The position of the grinding wheel 62 is adjusted by the numerical controller 90 so that the entire surface of the grindstone 83 hits the diamond 100 while the diamond 100 reciprocates once. Grinding may be performed by instructing a feed rate of 100.

  When the grinding of the cut surface e of the first surface is thus completed, the workpiece holding shaft 58 rises to the standby position together with the saddle 56, and the diamond 100 escapes from the grindstone 83.

  After that, when air is supplied to the air cylinder 73 of the Carbic coupling 72 and the chuck portion 70 is manually turned by 1/8 rotation, the surface of the grindstone 83 is the next cut surface e after the ground surface. And the next cut surface can be indexed. Then, the air is turned off to fix the Kirvic coupling 72. Thereafter, the same operation as the first cut surface is repeated for all eight cut surfaces e.

  When the grinding of all the eight cut surfaces e of the diamond 100 is finished in this way, the workpiece holding shaft 58 is raised to the standby position together with the saddle 56 again. The A-axis servomotor 80 is controlled based on the turning angle command corresponding to the cut surface f of the pavilion 2, and the workpiece holding shaft is set so that the first surface of the cut surface f is parallel to the surface of the grindstone 62. 58 turns. 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 100, and the description thereof is omitted to avoid repeated description.

  For each cut surface a to d of the crown 1 of the diamond 100, the diamond 100 is held in a direction opposite to that of FIG. 9 so that the crown 1 protrudes from the tip of the chuck portion 70 of the workpiece holding shaft 58, and is exactly the same as the pavilion 2. Thus, it can be ground.

  The last remaining diamond 4 table 4 has only one cut surface, and this cut surface is perpendicular to the rotational symmetry axis 110. Therefore, if the workpiece holding shaft 58 is fixed perpendicularly to the surface of the grindstone 83 after grinding of each cut surface of the crown 1 is completed, grinding can be performed without the need for indexing.

The front view which shows the 1st processing apparatus which comprises the diamond processing apparatus by one Embodiment of this invention. The front view which shows the principal part of the said 1st processing apparatus. Explanatory drawing of the state which hold | maintained the diamond between the workpiece | work axis | shaft and the tailstock in the said 1st processing apparatus. The side view of the 2nd processing apparatus which comprises the diamond processing apparatus by one Embodiment of this invention. The top view of the said 2nd processing apparatus. The side view which shows the workpiece | work holding shaft with which the said 2nd processing apparatus is provided. The partially notched side view which shows the turning axis | shaft part of the workpiece holding shaft. The side view of the state in which the workpiece holding shaft was turned to the machining standby position. Explanatory drawing which shows grinding of the pavilion in the brilliant cut of the diamond by one Embodiment of the processing method of this invention. The figure which shows the example of the grinding position and feed movement of a diamond with respect to a grinding wheel. 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 4 Table 5 Bezel 6 Curette 10 1st processing apparatus 11 Bed 12 X-axis table 14 Work axis 16 Work axis rotation apparatus 18 Whetstone 20 Whetstone rotation apparatus 29 Tailstock 30 Tailstock 50 Second Machining device 52 Bed 54 X-axis table 55 Column 56 Saddle 58 Workpiece holding shaft 60 Grinding wheel rotating device 62 Grinding wheel 66 X-axis servo motor 67 Z-axis servo motor 68 Y-axis servo motor 70 Chuck part 72 Carbic coupling (indexing) means)
74 Rotating shaft 80 A-axis servo motor 82 Grinding wheel shaft 83 Grinding wheel 100 Workpiece (diamond)
110 rotational symmetry axis

Claims (2)

A diamond processing method for finishing a diamond having a polyhedral cut structure including a crown, a pavilion, a table, and a girdle as a constituent part by grinding,
A rough processed diamond table is set as a temporary reference surface for processing, and the diamond is used as a reference between the work axis and the tailstock using the first processing apparatus having a work axis and a tailstock. A first grinding step in which the girdle is ground with a grindstone while being held coaxially and rotating the workpiece axis;
Using a second processing device having an indexing means on the workpiece holding shaft, the diamond is held on the workpiece holding shaft so that the rotational symmetry axis is coaxial, and the cut surface of the pavilion and crown is indexed while grinding the cut surface. A second grinding step of grinding at the end and finally finishing the table;
A method for processing diamond, comprising: A diamond processing apparatus that finishes a diamond having a polyhedral cut structure including a crown, a pavilion, a table, and a girdle by grinding,
A grindstone rotating device that moves on the bed in the Z-axis direction and has a cup-shaped grindstone, and a work shaft rotating device that includes a tailstock having a tailstock shaft facing the workpiece axis and moves on the bed in the X-axis direction. A first processing apparatus for grinding a diamond girdle;
A disk-shaped grinding wheel, a grinding wheel rotating device having a grinding wheel shaft that rotates the grinding wheel in a horizontal plane, an X-axis table that moves on the bed in the X-axis direction, and a movement on the X-axis table in the Z-axis direction And a saddle that moves in the vertical Y-axis direction along the guide of the column, and an indexing means for indexing a cut surface of the diamond held by the chuck portion. A second processing device for grinding a diamond crown, pavilion and table;
A diamond processing apparatus comprising:

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