JPWO2005037509A1 - Work cutting device and work cutting method - Google Patents

Abstract

Provided are a workpiece cutting apparatus and a workpiece cutting method capable of cutting a workpiece 66 stably and accurately with a simple configuration. In the workpiece cutting device 10, the workpiece 66 is arranged by the arrangement portion 59 so as to be cut by the inner peripheral blade 32. The slide base 54 of the moving unit 53 that supports the disposing unit 59 moves while being pulled by the falling weight 70 and sends the workpiece 66 toward the rotating inner peripheral blade 32. The projecting portion 56 provided on the bottom surface of the slide base 54 of the moving portion 53 and the restraining plate 82 of the speed restraining means 76 move in the direction of the feed stopper 84 (direction of arrow B) while being in contact with each other. The movement speed of the restraint plate 82 is slower than the movement speed of the slide base 54 by pulling the weight 70, and the slide base 54 feeds the workpiece 66 toward the inner peripheral blade 32 while suppressing the movement speed, and the workpiece 66 and the blade tip 32b. And contact.

Description

  The present invention relates to a workpiece cutting device and a workpiece cutting method, and more particularly to a workpiece cutting device and a workpiece cutting method for cutting a workpiece using an inner peripheral blade.

  Conventionally, in order to cut out a thin plate-like wafer from a work that is an ingot such as silicon or gallium arsenide, an inner peripheral blade blade having a thin circular plate-like base plate and a cutting edge provided on the inner peripheral edge of the base plate ( An inner peripheral blade cutting device that rotates an inner peripheral blade grindstone) at a high speed to cut the workpiece is used. By cutting using the inner peripheral cutting device, there is an advantage that a product with a good yield and a thin thickness can be obtained.

  In such an inner peripheral blade cutting device, cutting is performed by feeding a workpiece to the rotating inner peripheral blade blade or an inner peripheral blade blade rotating with respect to the workpiece. In general, the cutting resistance generated during the cutting process increases in proportion to the contact area (cutting area) between the workpiece and the cutting edge of the inner peripheral blade and the feed speed (cutting speed) of the workpiece or the inner peripheral blade. When the cutting resistance increases, there is a problem that the base plate of the thin inner peripheral blade is warped, the cutting edge is displaced, and the flatness accuracy (cutting accuracy) on the cut surface of the cut product is deteriorated. In particular, since the blade tip is likely to be displaced at the moment when the workpiece and the blade tip come into contact, that is, at the moment when cutting is started, it is necessary to suppress an excessive feed speed at the moment of starting cutting.

In order to prevent deterioration of the cutting accuracy of the workpiece, in Patent Document 1, a control device obtains a correction amount based on the displacement amount of the blade edge detected by a plurality of displacement detectors, and is used as a spindle displacement driving means for displacing the inner peripheral blade A technique for correcting the position of the blade edge by feedback is disclosed. Patent Document 2 discloses a technique in which a control device obtains a correction amount based on the amount of blade edge displacement detected by a plurality of sensors, and feeds back to an air pressure adjustment device to correct the blade edge position.
JP-A-4-122609 JP-A-5-318460

However, if feedback control as disclosed in Patent Literature 1 and Patent Literature 2 is used, the control system for the workpiece cutting device becomes complicated, and the cost of the workpiece cutting device increases.
SUMMARY OF THE INVENTION Therefore, a main object of the present invention is to provide a workpiece cutting device and a workpiece cutting device that do not require a complicated control system, can constitute a workpiece cutting device at low cost, and can stably and accurately cut a workpiece. Is to provide a method.

  According to one aspect of the present invention, there is provided a workpiece cutting device for cutting a workpiece by rotating an inner peripheral blade having a hollow disk-shaped base plate and a blade edge provided at an inner peripheral edge of the base plate. Holding part and placing the work at a position where it can be cut by the inner peripheral blade blade, moving part that supports and moves the placement part to move the work toward the inner peripheral blade, and falling motion connected to the moving part The weight that pulls and moves the moving part by moving, and the movement when at least the workpiece and the cutting edge of the inner peripheral blade contact with each other by applying a force to the moving part or weight to suppress the movement of the moving part due to the pulling of the weight There is provided a workpiece cutting device provided with a speed suppressing means for suppressing the moving speed of the part.

  According to another aspect of the present invention, there is provided a work cutting method for cutting a work by rotating an inner peripheral blade having a hollow disk-shaped base plate and a cutting edge provided on an inner peripheral edge of the base plate, The step of placing the workpiece by the placement portion at a position that can be cut by the inner peripheral blade blade, the step of connecting the weight to the moving portion that supports the placement portion, the moving portion is pulled by the falling weight and the work moves accordingly A step of feeding the blade toward the inner peripheral blade, a moving portion when at least the workpiece and the cutting edge of the rotating inner peripheral blade contact each other by applying a force to the moving portion or the weight to suppress the movement of the moving portion due to the pulling of the weight. A workpiece cutting method is provided that includes a step of starting cutting by suppressing the moving speed of the workpiece and thereby suppressing the feeding speed of the workpiece with respect to the inner peripheral blade.

  In this invention, the moving part is pulled by the falling weight, and thereby the work is fed toward the inner peripheral blade. Then, by applying a force to the moving part or the weight to suppress the movement of the moving part due to the pulling of the weight, in other words, a force in the direction opposite to the moving direction on the moving part or a force in the direction opposite to the falling direction on the weight. By substantially adding, the moving speed of the moving part at least when the workpiece and the inner peripheral blade contact each other is suppressed, and the excessive feed speed of the workpiece with respect to the inner peripheral blade is suppressed. Accordingly, the workpiece and the inner peripheral blade can be brought into contact with each other at an optimum workpiece feed rate, and the displacement of the cutting edge immediately after the start of cutting can be reduced, so that cutting can be started stably and with high accuracy. In addition, a work cutting device can be configured at low cost without requiring a complicated control system.

  Preferably, the speed suppressing means includes a guide bar provided with a thread groove, a driving means for rotating the guide bar, and a suppressing plate into which the guide bar is screwed and moved by the rotation of the guide bar. The restraining plate is arranged at a position that prevents the movement of the moving part due to the pulling of the weight, and the restraining plate moves in the same direction as the moving part and in contact with the moving part at a speed slower than the moving speed of the moving part due to the pulling of the weight. As a result, the moving speed of the moving unit is suppressed. In this way, the moving speed of the moving part can be suppressed only by making the moving speed of the restraining plate slower than the moving speed of the moving part, and a work cutting device can be configured at low cost without requiring a complicated control system. it can.

  Preferably, the speed suppressing means includes a resistance member that requires a certain force for movement. The resistance member is disposed at a position that prevents the movement of the moving part due to the pulling of the weight, and the moving part moves while pressing the resistance member, thereby suppressing the moving speed of the moving part. In this case, it is not necessary to control the speed suppressing means, and the work cutting device can be configured at a lower cost.

  Further preferably, the speed suppressing means includes a support part for supporting the weight and a lowering means for lowering the support part. The lowering means lowers the moving part of the moving part by lowering the supporting part that supports the weight at a speed that suppresses the falling of the weight and reducing the force that pulls the moving part of the weight. In this case, it is only necessary to set the descending speed of the support part so that the falling speed of the weight is slower than that when there is no support part, and a complicated control system is not required, and the work cutting device is configured at low cost. be able to.

  If the workpiece is brittle, if the workpiece feed rate is high when the workpiece contacts the blade of the inner peripheral blade, the cutting accuracy of the product obtained by cutting the workpiece will not only deteriorate, but chipping (chip ) May occur. In the present invention, even when the rare earth sintered alloy having a hard and brittle property and difficult to process is a workpiece, the workpiece can be cut stably and accurately without chipping.

  In addition, when using a water-soluble coolant obtained by diluting a water-soluble coolant stock solution with water when cutting the workpiece, water is the main component. It is easy to supply to the inner peripheral blade because of its large surface tension. Especially when the cutting edge of the inner peripheral blade consists of an abrasive layer electroplated with abrasive grains on the inner peripheral edge of a hollow disk-shaped base plate, the density of the abrasive grains is high (chip pocket is small) and water-soluble coolant is used. It is difficult to supply. Furthermore, in the inner peripheral blade, since the cutting edge is oriented in the center direction, the follower flow generated by the centrifugal force is firmly bound to the cutting edge, and it is difficult to supply the coolant to the cutting edge. For this reason, when a hard work is cut, the inner peripheral blade may be seized and further chipped due to insufficient supply of coolant. It is preferable to use a water-soluble coolant obtained by diluting a water-soluble coolant stock solution containing 5 wt% to 20 wt% of a surfactant and 10 wt% to 40 wt% of a lubricant with water. In this case, coolant can be appropriately supplied to the cutting edge of the inner peripheral blade, and seizure and chipping can be prevented. Further, the wear of the cutting edge can be optimized, and the inner peripheral blade that performs high-precision cutting can be extended in life.

It is a perspective view which shows the outline of one Embodiment of this invention. (A) is the front solution figure which shows the outline of one Embodiment of this invention, (b) is the side view solution figure. (A) is an illustration figure which shows the fixed mode of an inner peripheral blade blade, (b) is a fragmentary perspective view showing the discharge port of a coolant nozzle, (c) is an illustration figure showing the discharge port neighborhood of a coolant nozzle. is there. It is an illustration figure which shows an example of the workpiece | work cut by the workpiece cutting device. It is an illustration figure which shows the positional relationship of the workpiece | work and the blade edge | tip of an internal peripheral blade, and the feed speed of a workpiece | work. It is an illustration figure which shows operation | movement of a speed suppression means. It is an illustration figure which shows the other example of the workpiece | work cut by a workpiece | work cutting device. It is an experimental result which shows the relationship between the surface tension of a coolant, and cutting accuracy, (a) is a table, (b) is a graph. It is an illustration figure for demonstrating the measurement point of the thickness of a product. It is an experimental result which shows the relationship between the discharge pressure of coolant and cutting | disconnection precision, (a) is a table, (b) is a graph. It is a side view solution figure which shows the outline of other embodiment of this invention. (A) is a front view solution figure which shows the outline of other embodiment of this invention, (b) is the side view solution figure.

Explanation of symbols

10, 100, 200 Workpiece cutting device 12 Bet 32 Inner blade blade 48 Coolant nozzle 50 Guide groove 52 Guide hole 53 Moving portion 54 Slide base 56 Projection portion 59 Arrangement portion 66 Workpiece 70 Weight 76, 102, 202 Speed control means 78, 104, 204 Guide member 80, 206 Guide rod 82 Suppression plate 84, 106, 220 Feed stopper 86, 210 Rewind stopper 108, 222 Return stopper 110 Resistance member 208 Lift plate 216 Support plate

Embodiments of the present invention will be described below with reference to the drawings.
1 and 2, a workpiece cutting device 10 according to an embodiment of the present invention has an inner peripheral blade 32 (described later) arranged vertically, and a workpiece 66 (with respect to the rotating inner peripheral blade 32). This is an inner peripheral blade cutting device of a type that performs cutting processing by sending (described later).

  The workpiece cutting device 10 includes a bed 12. A rotation support portion 14 is provided on the bed 12. A rotation shaft 18 fixed to the chuck body 16 is inserted into the rotation support portion 14, and the rotation shaft 18 is supported by bearings 20 and 22. Thereby, the chuck body 16 is rotatably supported.

  As shown in FIG. 2A, a pulley 24 is attached to the rotation shaft 18 in the rotation support portion 14. A rotating shaft motor 26 is disposed in the bed 12, and a motor pulley 28 is attached to the rotating shaft of the rotating shaft motor 26. The pulley 24 and the motor pulley 28 are connected by a belt 30. The rotary shaft 18 is rotated by driving the rotary shaft motor 26 and rotating the belt 30, and the chuck body 16, the inner peripheral blade 32 and the tension head 34 are moved in the direction of arrow A as shown in FIG. Rotate.

  As shown in FIG. 3A, the outer peripheral edge of the inner peripheral blade 32 is sandwiched and fixed between the end face of the chuck body 16 and the end face of the tension head 34.

  Specifically, fixing bolts 38 are screwed into a plurality of bolt holes 36 provided on the outer peripheral side of the tension head 34, and their tips are inserted into insertion holes 40 provided on the outer peripheral edge of the inner peripheral blade 32. Then, the inner peripheral blade 32 is fixed by screwing the tip of the fixing bolt 38 into the bolt hole 42 provided in the chuck body 16 and tightening it. Further, the inner peripheral blade 32 can be lifted in the outer peripheral direction by screwing a press bolt 46 into a plurality of press bolt holes 44 provided on the inner peripheral side of the tension head 34 and tightening it.

  The inner peripheral blade 32 includes, for example, a base plate 32a made of a hollow disc-shaped stainless steel alloy having a thickness of about 0.3 mm, and a diamond plating particle on the inner periphery of the base plate 32a and a metal plating solution such as a nickel solution. And a blade having a thin thickness, including a cutting edge 32b of an abrasive layer formed by electroplating.

  Further, a coolant nozzle 48 is disposed in the vicinity of the blade edge 32b. The coolant nozzle 48 continuously discharges coolant supplied from a coolant supply unit (not shown) from the discharge port 48a and supplies the coolant to the cutting edge 32b. As can be seen from FIGS. 3B and 3C, the discharge port 48a has a shape in which the tip of the coolant nozzle 48 is broken. The coolant is discharged from the discharge port 48a so as to wrap the blade edge 32b. The supplied coolant is adjusted to be 22 ° C. to 35 ° C. at the time of discharge by a temperature adjusting unit (not shown). The discharge pressure is adjusted to 0.05 MPa to 0.2 MPa. If it is less than 0.05 MPa, the cutting edge 32b is seized. On the other hand, if it exceeds 0.2 MPa, the cutting edge 32b bends and the cutting accuracy decreases.

  The coolant supplied to the cutting edge 32b is obtained by adding a water-soluble coolant stock solution of about 2 wt% to 10 wt% to water. The main composition of this coolant stock solution is as described in Japanese Patent Application Laid-Open No. 2003-82335. This coolant stock solution contains 5 wt% to 20 wt% of a surfactant having 10 to 20 carbon atoms such as carboxylic acid in order to increase the permeability to the cutting edge 32b, and improves the lubricity between the cutting edge 32b and the workpiece 66 (described later). Therefore, it contains 10 wt% to 40 wt% of a lubricant having a molecular weight of 76 to 10000 such as glycols. Specifically, WS # 252 (manufactured by Yushiro Chemical Industry Co., Ltd.) or the like is used as the coolant stock solution.

  The coolant is adjusted so that the surface tension at 25 ° C. is 20 mN / m to 40 mN / m. If it is less than 20 mN / m, the abrasive grain slips between the abrasive grains and the workpiece 66 during cutting, and effective cutting cannot be performed. On the other hand, if it exceeds 40 mN / m, an increase in cutting resistance is observed due to insufficient supply of coolant between the abrasive grains and the workpiece 66.

  1 and 2, a guide groove 50 is formed on the bed 12, and a guide hole 52 that opens the upper surface of the bet 12 is formed in the guide groove 50 at the center in the longitudinal direction of the guide groove 50. . A moving portion 53 is disposed in the guide groove 50. The moving portion 53 includes a slide base 54 that can slide in the longitudinal direction on the guide groove 50, a protrusion 56 that is provided on the bottom surface of the slide base 54 and protrudes into the bed 12 through the guide hole 52, and the slide base 54, and a support member 58 standing on the surface 54.

  The placement unit 59 is supported by the moving unit 53. The arrangement portion 59 includes an indexing mechanism 60 supported by the support member 58, a fixing jig 62 supported by the indexing mechanism 60, and a sticking plate 64 such as carbon provided on the main surface of the fixing jig 62. The workpiece 66 is fixed to the main surface of the sticking plate 64. The indexing mechanism 60 moves the fixing jig 62 in a direction (arrow X direction) perpendicular to the inner peripheral blade 32 and is arranged near the center of the inner peripheral blade 32 so that the workpiece 66 can be cut. That is, the thickness of the product obtained by cutting the workpiece 66 by the indexing mechanism 60 can be adjusted.

  The indexing mechanism 60 may be driven by a signal input from a control unit (not shown), or may be driven manually by attaching a handle or the like, for example.

  Further, one end of a linear member 68 made of, for example, a piano wire or a steel wire is connected to the front surface of the slide base 54, and a weight 70 is connected to the other end of the linear member 68. The linear member 68 connecting the slide base 54 and the weight 70 is guided by a guide roller 74 supported by the roller support portion 72. The slide base 54 is pulled by the falling weight 70, slides along the guide groove 50 and moves in the direction of arrow B (see FIG. 2B), and moves the workpiece 66 from the vicinity of the center of the inner peripheral blade 32 to the outer peripheral direction. Send to.

  For the weight 70, an iron lump having a weight 3 to 6 times the weight of the workpiece 66 is used. For example, when the weight of the workpiece 66 is 300 g to 400 g, a 1.6 kg iron ingot is used for the weight 70.

  Furthermore, a speed suppressing means 76 that suppresses the moving speed of the moving portion 53 is provided below the guide hole 52 in the bed 12. The speed suppression means 76 includes a guide member 78 having a U-shaped cross section, a guide bar 80 in which a thread groove is formed, a suppression plate 82 into which the guide bar 80 is screwed and slides, and one end of the guide member 78. A feed stopper 84 joined to the guide member 78, a rewind stopper 86 joined to the other end of the guide member 78, and a motor 88 connected to the guide rod 80.

  The feed stopper 84 rotatably holds the guide rod 80, and the guide rod 80 is inserted into the rewind stopper 86. In the bed 12, the guide member 78, the feed stopper 84, and the rewind stopper 86 are fixed, the feed stopper 84 restricts the tip position of the sliding restraining plate 82, and the rewind stopper 86 is the rear end of the protrusion 56. Regulate the position.

The guide bar 80 is rotationally driven at a constant speed by a motor 88 connected thereto, and moves the suppression plate 82 in the direction of the feed stopper 84 (arrow B direction) or the rewind stopper 86 (opposite direction of arrow B). . At this time, the suppression plate 82 slides on the guide member 78 without rotating with the rotation of the guide rod 80.
The rotational speed and direction of the motor 88 can be changed by a control unit (not shown).

  For example, a rare earth sintered alloy is used as the workpiece 66 cut by the workpiece cutting apparatus 10 configured as described above. An example of the shape of the workpiece 66 which is a rare earth sintered alloy is shown in FIG.

  Referring to FIG. 4, work 66 can be arranged in the vicinity of the center of inner peripheral blade 32 by arrangement portion 59 by integrating a rectangular parallelepiped rare earth sintered alloy with an adhesive or the like in order to improve manufacturing efficiency. It is configured as a rectangular parallelepiped of an appropriate size within the limits. A product obtained by cutting the workpiece 66 having such a shape is used, for example, as a magnet for driving an optical pickup lens.

Next, the main operation of the workpiece cutting apparatus 10 will be described with reference to FIGS.
As shown in FIG. 5A, a rare earth sintered alloy workpiece 66 having the shape shown in FIG. 4 is arranged near the center of the inner peripheral blade 32 by the arrangement portion 59 before the operation of the workpiece cutting device 10. A weight 70 having a weight 3 to 6 times the weight of the workpiece 66 is connected to the slide table 54 by the linear member 68. At this time, as shown in FIG. 6A, the projecting portion 56 is sandwiched between the restraining plate 82 and the rewinding stopper 86, so that the slide base 54 cannot move.

  When a start button (not shown) is pressed, the rotary shaft motor 26 is driven, the inner peripheral blade 32 is rotated, and coolant whose temperature is adjusted is supplied to the blade tip 32b from the discharge port 48a. Then, the motor 88 of the speed suppression means 76 is driven, and the suppression plate 82 moves in the direction of the feed stopper 84 as shown in FIG. 6B, and the feed operation of the workpiece 66 is started.

  The moving speed of the restraining plate 82 is slower than the moving speed of the slide base 54 pulled by the fall of the weight 70, and the restraining plate 82 and the protrusion 56 move in the direction of the feed stopper 84 while being in contact with each other. That is, the slide base 54 moves in the direction of the arrow B while its movement speed is suppressed by the suppression plate 82, and feeds the work 66 toward the inner peripheral blade 32 that rotates, as shown in FIG. Cutting is started by bringing the workpiece 66 and the blade edge 32b into contact with each other.

  Here, if the movement speed of the restraining plate 82 is intermittently increased during the cutting, the cutting edge 32b is vibrated in the front-rear direction, the cutting resistance at the cutting portion is reduced, and the blade thickness is reduced. However, the cutting edge 32b is difficult to bend. In addition, since cutting resistance is reduced, cutting accuracy is also improved.

  As shown in FIG. 5C, as the work 66 advances, the contact area (cutting area) between the work 66 and the cutting edge 32b increases, and the cutting resistance increases accordingly. As the cutting resistance increases, the feed load of the workpiece 66 (moving load of the slide table 54) also increases, and the moving speed of the slide table 54 and hence the feed speed of the workpiece 66 decreases. Thus, since the moving speed of the restraint plate 82 is constant while the moving speed of the slide base 54 is lowered, the workpiece 66 is fed (cut) by a certain amount after the start of cutting. As shown in (c), the protrusion 56 and the suppression plate 82 are separated. Then, the slide table 54 moves only by pulling the falling weight 70 and feeds the workpiece 66.

  As shown in FIG. 5D, when the feeding of the workpiece 66 proceeds, the cutting area becomes maximum and constant at a certain point, and the feeding speed of the workpiece 66 also becomes constant.

  As shown in FIG. 5 (e), when the workpiece 66 is further fed, the blade edge 32 b reaches the sticking plate 64. Since the cutting resistance of the sticking plate 64 made of carbon is smaller than the cutting resistance of the work 66 made of rare earth sintered alloy and the cutting area of the work 66 is also reduced, the moving speed of the slide base 54 and thus the feeding speed of the work 66 are increased. To do.

Thereafter, as shown in FIG. 6D, when the protruding portion 56 comes into contact with the suppression plate 82 that is in contact with the feed stopper 84 again, the feed operation of the workpiece 66 is finished. At this time, the workpiece 66 and the inner peripheral blade 32 are in a state as shown in FIG. 5F, and the cutting process is completed.
After the cutting process is completed, by driving the motor 88 in the reverse direction, the restraining plate 82 moves in the direction of the rewinding stopper 86 while pushing the protrusion 56, and returns to the state of FIG. Note that the position return operation of the protrusion 56 and the suppression plate 82 may be performed, for example, by pressing a return button, or may be automatically performed by attaching a sensor to the feed stopper 84.

  According to such a workpiece cutting device 10, the workpiece 66 and the inner peripheral blade 32 can be brought into contact with each other at an optimal feed rate of the workpiece 66. Accordingly, even the inner peripheral blade 32 having a small thickness can reduce the displacement of the cutting edge 32b immediately after the start of cutting, and even if the workpiece 66 is a rare earth sintered alloy having a hard and brittle property, there is no chipping and stability. Thus, the cutting process can be started with high accuracy. Moreover, the moving speed of the moving part 53 can be suppressed only by making the moving speed of the restraint plate 82 slower than the moving speed of the slide base 54, a complicated control system is not required, and the work cutting apparatus 10 is configured at low cost. As a result, the manufacturing cost of the product obtained by cutting can be reduced.

  In addition, by using a water-soluble coolant obtained by diluting a water-soluble coolant stock solution containing 5 wt% to 20 wt% of a surfactant and 10 wt% to 40 wt% of a lubricant with water, it is suitable for the cutting edge 32b of the inner peripheral blade 32. The coolant can be supplied to the steel, and seizure and chipping can be prevented. Further, the wear of the cutting edge 32b can be optimized, and the inner peripheral blade 32 that performs high-accuracy cutting can be extended. In addition, this water-soluble coolant can be used more effectively by adjusting the temperature to be 22 ° C. to 35 ° C. when supplied to the inner peripheral blade 32 (at the time of discharge).

  The coolant is preferably adjusted so that the surface tension at 25 ° C. is 20 mN / m to 40 mN / m. By setting the surface tension to 20 mN / m to 40 mN / m, even in the workpiece cutting device 10 where the coolant does not easily remain on the blade edge 32b due to centrifugal force or the like at the time of cutting, the coolant remains on the blade edge 32b appropriately, and good cutting becomes possible. .

  Furthermore, the discharge pressure is desirably adjusted to 0.05 MPa to 0.2 MPa. By setting the discharge pressure to 0.05 MPa to 0.2 MPa, seizure and deformation of the cutting edge 32b due to insufficient supply of coolant to the cutting edge 32b are suppressed, and cutting can be performed with high accuracy.

  In addition, the shape of the workpiece | work 66 comprised integrally with a rectangular parallelepiped rare earth sintered alloy is not restricted to what is shown in FIG. Further, if the cross-sectional area is large, it may be cut by itself.

  In addition to the workpiece 66 having the shape shown in FIG. 4, various workpieces 66 are cut by the workpiece cutting apparatus 10. An example of another shape of the workpiece 66, which is a rare earth sintered alloy, is shown in FIG.

  As shown in FIG. 7A, a rare earth sintered alloy having a substantially trapezoidal cross section with an arc on the top and bottom may be used as a workpiece 66 for cutting. A product obtained by cutting the workpiece 66 having such a shape is used, for example, as a magnet for driving a VCM (voice coil motor). Further, as shown in FIG. 7B, in order to improve the manufacturing efficiency if the size is small, the workpiece 66 having the shape shown in FIG. 7A may be integrated with an adhesive or the like. In addition, the shape of the workpiece | work 66 comprised by integrating the rare earth sintered alloy of the shape shown to Fig.7 (a) is not restricted to what is shown in FIG.7 (b).

As the adhesive used here, it is desirable to use a mixture of CaCO ₃ (calcium carbonate), collagen (niwa), turpentine and colophonium (pine and ni). This adhesive does not wrap around the inner peripheral blade having a small blade thickness, and seizure of the cutting edge 32b and peeling of the abrasive grains due to variation in cutting load are less likely to occur. Further, the workpiece 66 does not come off. The component ratio of the adhesive is preferably CaCO ₃ : Niwa: Matsuya = 1: 0.6 to 1.0: 0.6 to 1.0.

In order to improve manufacturing efficiency, a cylindrical rare earth sintered alloy is integrated with an adhesive or the like, and a workpiece 66 is formed into a shape as shown in FIGS. Sometimes. A product obtained by cutting the rare earth sintered alloy workpiece 66 having such a shape is used, for example, as a magnet for driving an optical pickup lens. In addition, the shape of the workpiece | work 66 comprised by integrating cylindrical rare earth sintered alloy is not restricted to what is shown in FIG.7 (c) to FIG.7 (e). Moreover, if the area of the cross section is large, it may be cut by itself.
Further, as shown in FIG. 7 (f), a cylindrical rare earth sintered alloy may be used as a workpiece 66 for cutting.

  When cutting the workpiece 66 having the shape shown in FIG. 7F, the cutting area becomes maximum immediately after the start of cutting. As the cutting progresses, the cutting area decreases rapidly. At this time, the protrusion 56 and the suppression plate 82 are not separated from each other, and there is a possibility that the cutting process is performed while the moving speed of the slide base 54 is suppressed. Alternatively, there is a possibility that the projecting portion 56 and the restraining plate 82 once separated come into contact again during the cutting process, and the moving speed of the slide base 54 is restrained again. As a result, the time required for the feeding operation of the workpiece 66 and the time required for the cutting process become longer, and the production efficiency may be reduced. Therefore, in order to prevent a reduction in manufacturing efficiency, the rotational speed of the motor 88 may be increased via the control unit after the contact between the workpiece 66 and the cutting edge 32b, and the moving speed of the suppression plate 82 may be increased. In addition, a load sensor may be attached to the fixing jig 62 to automatically increase the rotational speed of the motor 88 and increase the moving speed of the suppression plate 82 when a load exceeding a certain level is detected.

  Needless to say, various shapes of the workpiece 66 other than those shown in FIGS. 4 and 7 can be considered.

  Next, an experimental example in which the workpiece 66 is cut by the workpiece cutting device 10 and the workpiece cutting device not provided with the speed suppressing means 76 and the cutting accuracy of the obtained product is compared will be described. The difference in configuration between the workpiece cutting apparatus 10 and the workpiece cutting apparatus that does not include the speed suppression means 76 is only the presence or absence of the speed suppression means 76.

Table 1 shows the processing conditions.

  The workpiece cutting apparatus 10 and the workpiece cutting apparatus not provided with the speed suppressing means 76 were subjected to experiments under the same processing conditions. As shown in Table 1, in this experimental example, artificial diamond having an average abrasive grain size of 60 μm as an abrasive material was electroplated on the inner peripheral edge of a base plate 32a having a thickness of 0.1 mm using a nickel solution to obtain a thickness of 0. An inner peripheral blade 32 having a cutting edge 32b made of a 26 mm abrasive layer was used. As a material of the base plate 32a, a stainless steel alloy having super tensile strength characteristics was used. Moreover, the rotational speed (peripheral speed) of the inner peripheral blade 32 was 1130 m / min.

For the workpiece 66, a rare earth sintered alloy having a shape shown in FIG. 7A, which is called a VCM block and has a cross-sectional area (end surface area) of about 7.6 cm ² was used. Specifically, as the rare earth sintered alloy, Nd—Fe—B based sintered alloy containing liquid Fe and subjected to liquid phase sintering was used. Nd—Fe—B-based sintered alloys are hard-to-work materials having particularly hard and brittle properties among rare earth sintered alloys.

  As the weight 70, a 1.6 kg iron ingot was used.

  As the coolant, WS # 252 manufactured by Yushiro Chemical Industry Co., Ltd. diluted with water by 10 wt% was used. The coolant was adjusted to 25 ° C. during discharge, and was supplied to the blade edge 32b at a discharge amount of 1.0 L / min.

The results shown in Table 2 were obtained by experiment.

  In this experiment, each workpiece 66 was cut five times by the workpiece cutting device 10 and the workpiece cutting device not provided with the speed suppressing means 76, and this was repeated for 15 workpieces 66.

  In the workpiece cutting device not provided with the speed suppressing means 76, the average thickness of the obtained product is 3.418 mm, whereas in the workpiece cutting device 10, it is 3.404 mm, which is close to the target cutting thickness (3.4 mm). It was possible to cut with high accuracy.

  Further, in the workpiece cutting device not provided with the speed suppressing means 76, the thickness variation of the obtained product is 0.014 mm, whereas in the workpiece cutting device 10, the thickness variation is 0.0051 mm, and the thickness variation is about one third. It was possible to reduce it.

  The “thickness average” is a value obtained by measuring, summing, and averaging the thicknesses of all products obtained by cutting. In addition, the “thickness variation” in this experimental example and the next experimental example means that the thickness error with respect to the target cutting thickness (for example, 3.4 mm in this experimental example) is detected for all products obtained by the cutting process. The average value.

  Moreover, the experiment which compares the durability of the internal peripheral blade 32 using the coolant 1 and the coolant 2 which differ in the workpiece | work cutting device 10 was conducted.

  As the coolant 1, a water-soluble coolant in which a water-soluble coolant stock solution containing 10 wt% of a surfactant with carboxylic acid and 20 wt% of a lubricant with ethylene glycol was diluted 10 times with water was used. Further, as the coolant 2, a water-soluble coolant in which a water-soluble coolant stock solution containing 4 wt% of a surfactant with carboxylic acid and 8 wt% of a lubricant with ethylene glycol was diluted 10 times with water was used. Note that the temperature of the coolant 1 and the coolant 2 was adjusted to 25 ° C. at the time of discharge.

Table 3 shows the processing conditions.

  As shown in Table 3, in this experimental example, a base plate 32a having a thickness of 0.1 mm and an artificial diamond having an average abrasive grain size of 60 μm as an abrasive material were electroplated on the inner periphery of the base plate 32a using a nickel solution. An inner peripheral blade 32 including a cutting edge 32b made of an abrasive grain layer having a thickness of 0.26 mm was used. As a material of the base plate 32a, a stainless steel alloy having super tensile strength characteristics was used. Moreover, the rotational speed (peripheral speed) of the inner peripheral blade 32 was 1130 m / min.

The workpiece 66 is called a □ block, and its end and width are 20.2 mm and 52 mm, the depth is 30 mm, and the cross-sectional area is about 10.5 cm ^2. The Nd—Fe— having the shape shown in FIG. A B-based sintered alloy was used.

  As the weight 70, a 1.0 kg iron ingot was used.

The results shown in Table 4 were obtained by experiment.

  As shown in Table 4, when cutting was performed by supplying the coolant 2 to the blade edge 32b, the average life of the inner peripheral blade 32 was 800 shots. On the other hand, when the coolant 1 was supplied to the cutting edge 32b and the cutting process was performed, the average life of the inner peripheral blade 32 was 1200 shot, and the inner peripheral blade 32 could be extended.

  Further, by using the coolant 1, it was possible to reduce the thickness average error and thickness variation with respect to the target cutting thickness (0.66 mm) as compared with the case where the coolant 2 was used. That is, by using the coolant 1, it was possible to perform cutting with higher accuracy.

  Further, an experimental example will be described in which the surface tension of the coolant is changed in the workpiece cutting apparatus 10 and the thickness variation of products obtained by cutting the workpiece 66 for each different surface tension is obtained.

Table 5 shows the processing conditions.

As shown in Table 5, in this experimental example, artificial diamond having an average abrasive grain size of 60 μm as an abrasive material was electroplated on the inner peripheral edge of a base plate 32a having a thickness of 0.1 mm using a nickel solution to have a thickness of 0. An inner peripheral blade 32 having a cutting edge 32b made of a 26 mm abrasive layer was used. As a material of the base plate 32a, a stainless steel alloy having super tensile strength characteristics was used. Moreover, the rotational speed (peripheral speed) of the inner peripheral blade 32 was 1130 m / min.
For the workpiece 66, a 35 mm × 30 mm × 30 mm Nd—Fe—B sintered alloy having the shape shown in FIG. 4 was used.

  As the weight 70, a 1.6 kg iron ingot was used.

  As the coolant, WS # 252 manufactured by Yushiro Chemical Industry Co., Ltd. diluted with water was used. The coolant was adjusted to 25 ° C. during discharge, and the discharge pressure was set to 0.15 MPa. Here, the coolant discharge pressure refers to the coolant pressure at the discharge port 48 a of the coolant nozzle 48.

  In this experiment, the workpiece cutting apparatus 10 performed five cutting operations on one workpiece 66, and this was repeated for 15 workpieces 66.

  As a result of the experiment, as shown in FIGS. 8 (a) and (b), it was found that if the surface tension of the coolant is in the range of 20 mN / m to 40 mN / m, the thickness variation of the obtained product can be reduced. Therefore, if the surface tension of the coolant is within this range, cutting can be performed with higher accuracy.

  The “thickness variation” in this experimental example and the next experimental example is a value obtained by detecting and summing the thickness errors of all products obtained by cutting. Here, the “thickness error” for the product is obtained as follows. For the product obtained by cutting, the thicknesses of the nine measurement points shown in FIG. 9 are measured with, for example, a micrometer, and the difference between the maximum value and the minimum value is defined as the thickness error for the product.

Further, an experimental example will be described in which the coolant discharge pressure is changed in the workpiece cutting apparatus 10 and the thickness variation of products obtained by cutting the workpiece 66 is obtained for each different discharge pressure.
The processing conditions are the same as in Table 5 above.

  That is, in this experimental example, an artificial diamond having an average abrasive grain size of 60 μm as an abrasive material is electroplated using nickel solution on the inner periphery of a base plate 32a having a thickness of 0.1 mm, and an abrasive grain layer having a thickness of 0.26 mm. An inner peripheral blade 32 having a cutting edge 32b made of was used. As a material of the base plate 32a, a stainless steel alloy having super tensile strength characteristics was used. Moreover, the rotational speed (peripheral speed) of the inner peripheral blade 32 was 1130 m / min.

  For the workpiece 66, a 35 mm × 30 mm × 30 mm Nd—Fe—B sintered alloy having the shape shown in FIG. 4 was used.

  As the weight 70, a 1.6 kg iron ingot was used.

  As the coolant, WS # 252 manufactured by Yushiro Chemical Industry Co., Ltd. diluted with water was used. The coolant was adjusted to 25 ° C. during discharge, and the surface tension was set to 30 mN / m.

  In this experiment, the workpiece cutting apparatus 10 performed five cutting operations on one workpiece 66, and this was repeated for 15 workpieces 66.

  As a result of the experiment, as shown in FIGS. 10A and 10B, it was found that if the coolant discharge pressure is in the range of 0.05 MPa to 0.2 MPa, the thickness variation of the obtained product can be reduced. Therefore, if the discharge pressure of the coolant is within this range, cutting can be performed with higher accuracy.

Next, a workpiece cutting device 100 according to another embodiment of the present invention will be described with reference to FIG.
In the workpiece cutting device 100, a speed suppressing unit 102 is used instead of the speed suppressing unit 76 in the workpiece cutting apparatus 10 described above. Since the other configuration is the same as that of the workpiece cutting device 10, the redundant description thereof is omitted.

  In the workpiece cutting device 100, a speed suppressing unit 102 that suppresses the moving speed of the moving unit 53 is provided in the bed 12, and the speed suppressing unit 102 is joined to a guide member 104 having a U-shaped cross section and one end of the guide member 104. A feed stopper 106, a return stopper 108 joined to the other end of the guide member 104, and a resistance member 110 that slides on the guide member 104.

  In the bed 12, the guide member 104, the feed stopper 106 and the return stopper 108 are fixed, and the resistance member 110 is disposed at a position where the protrusion 56 is sandwiched between the return stopper 108. The resistance member 110 is a weight such as an iron lump, for example, and is lighter than the weight 70.

  In such a speed control means 102 of the workpiece cutting device 100, the protrusion 56 that moves in the direction of the arrow B when the weight 70 is dropped moves while pressing the resistance member 110 that requires a certain force to move, so that the slide base The moving speed of 54 and thus the excessive feeding speed of the workpiece 66 is suppressed.

  When the workpiece cutting device 100 is in a stopped state, the weight 70 is supported by a support base (not shown) so as not to fall. Alternatively, the weight 70 is removed.

  Further, after the cutting process is completed, the slide table 54 is manually pushed back in the direction of the return stopper 108 (the direction opposite to the arrow B). At this time, the weight 70 may be supported by a support base or may be removed. In order to move the resistance member 110 in contact with the feed stopper 106 in the direction of the return stopper 108, for example, an opening / closing opening (not shown) is provided on the side surface of the bed 12, and the opening / closing opening is opened, and the resistance member is manually formed. 110 may be moved.

  According to such a workpiece cutting device 100, the workpiece 66 and the inner peripheral blade 32 can be brought into contact with each other at an optimum feed speed of the workpiece 66. Accordingly, even the inner peripheral blade 32 having a small thickness can reduce the displacement of the cutting edge 32b immediately after the start of cutting, and even if the workpiece 66 is a rare earth sintered alloy having a hard and brittle property, there is no chipping and stability. Thus, the cutting process can be started with high accuracy. Moreover, it is not necessary to control the speed suppression means 102, the workpiece cutting device 100 can be configured at a lower cost, and the manufacturing cost of a product obtained by cutting can be reduced.

Furthermore, with reference to FIG. 12 (a) and (b), the workpiece | work cutting device 200 of other embodiment of this invention is demonstrated.
In the workpiece cutting apparatus 200, a speed suppressing means 202 is used instead of the speed suppressing means 76 in the workpiece cutting apparatus 10 described above. In the workpiece cutting device 200, the description of the part configured similarly to the workpiece cutting device 10 is omitted.

  In the bed 12, the speed suppressing means 202 includes a guide member 204 having a U-shaped cross section, a guide bar 206 in which a thread groove is formed, a lift plate 208 into which the guide bar 206 is screwed and slides on the guide member 204, a guide A rewinding stopper 210 joined to the upper end of the member 204 and a motor 212 connected to the guide rod 206 are included.

  Further, the speed suppressing means 202 includes a support plate 216 that is connected to the tip of the lift plate 208 that protrudes from the lift hole 214 formed on the side surface of the bed 12 and supports the weight 70.

  The lower end portion of the guide member 204 is joined to the bottom surface in the bed 12. The guide bar 206 is inserted through the rewinding stopper 210 and is rotatably held by a bearing 218 provided on the bottom surface in the bed 12.

  In the workpiece cutting device 200, a feed stopper 220 and a return stopper 222 are provided below the guide groove 50 in the bed 12. The feed stopper 220 restricts the front end position of the protrusion 56, and the return stopper 222 restricts the rear end position of the protrusion 56.

  The guide rod 206 is rotationally driven at a constant speed by a motor 212 connected thereto, and lowers or raises the lift plate 208 and the support plate 216 connected to the lift plate 208. At this time, the lift plate 208 slides up and down on the guide member 204 and moves without swinging left and right as the guide rod 206 rotates.

  The motor 212 starts rotating when a start button (not shown) is pressed. Further, the rotation speed and rotation direction of the motor 212 can be changed by a control unit (not shown).

  In the speed suppressing means 202 of the workpiece cutting device 200 as described above, the support plate 216 that is connected to the lift plate 208 and supports the weight 70 is lowered at a speed that suppresses the falling of the weight 70, whereby the slide base 54 of the weight 70. Is reduced in the direction of the arrow B, and the moving speed of the slide base 54 and the excessive feeding speed of the work 66 are suppressed.

  The workpiece 66 feeding operation (cutting operation) when the workpiece 66 shown in FIG. 4 is cut by the workpiece cutting apparatus 200 is the same as the workpiece 66 feeding operation of the workpiece cutting apparatus 10.

  As the feed of the workpiece 66 proceeds after the cutting starts, the cutting area of the workpiece 66 increases (see FIG. 5C), and the cutting resistance increases accordingly. As the cutting resistance increases, the feed load of the workpiece 66 also increases, and the moving speed of the slide table 54 and thus the feed speed of the workpiece 66 decreases. In this way, the moving speed of the slide base 54 decreases, but the descending speed of the support plate 216 is constant. Therefore, when the work 66 is fed by a certain amount after the start of cutting, the weight 70 and the support plate 216 are separated from each other. Leave.

  Then, the slide table 54 moves only by pulling the falling weight 70, and the cutting area becomes maximum and constant at a certain point (see FIG. 5D), and accordingly, the feed speed of the workpiece 66 is also constant.

  When the workpiece 66 is further fed, the cutting edge 32b reaches the sticking plate 64 (see FIG. 5E). Since the cutting resistance of the sticking plate 64 made of carbon is smaller than the cutting resistance of the workpiece 66 and the cutting area of the workpiece 66 is also reduced, the falling speed of the weight 70 and thus the feeding speed of the workpiece 66 are increased.

  Thereafter, the protrusion 56 and the feed stopper 220 come into contact with each other, and the feed operation of the workpiece 66 is completed.

  After the end of the cutting process, the slide table 54 is pushed back in the direction of the return stopper 222 (the direction opposite to the arrow B) by hand. At this time, the weight 70 is again supported at the position shown in FIG. 12A by the support plate 216 that is lifted by reversing the rotation direction of the motor 212. The position returning operation of the weight 70 may be performed, for example, by pressing a return button, or may be automatically performed by attaching a sensor to the suppression plate 216.

  According to such a workpiece cutting device 200, the workpiece 66 and the inner peripheral blade 32 can be brought into contact with each other at an optimum feed speed of the workpiece 66. Accordingly, even the inner peripheral blade 32 having a small thickness can reduce the displacement of the cutting edge 32b immediately after the start of cutting, and even if the workpiece 66 is a rare earth sintered alloy having a hard and brittle property, there is no chipping and stability. Thus, the cutting process can be started with high accuracy. In addition, the moving speed of the moving portion 53 can be suppressed only by setting the descending speed of the support plate 216 so as to suppress the falling of the weight 70, so that a complicated control system is not required, and the work cutting device is low-cost. 200 can be configured, and as a result, the manufacturing cost of a product obtained by cutting can be reduced.

  The present invention can also be applied to a workpiece cutting device of the type in which the inner peripheral blades are laid sideways.

  Further, the present invention can also be applied to a work cutting apparatus of a type that performs cutting by sending an inner peripheral blade to a work.

  Furthermore, it is applicable also to the workpiece | work cutting device which uses the outer periphery blade blade (peripheral blade grindstone) which has a blade edge in the outer periphery of a base plate.

  The workpiece used in the present invention is not limited to rare earth sintered alloys, but widely targets those that are cut with high accuracy, such as silicon and gallium arsenide.

  Although the present invention has been described and illustrated in detail, it is clear that it has been used merely as an illustration and example and should not be construed as limiting, and the spirit and scope of the present invention are attached Limited only by the language of the claims.

Claims (10)

A workpiece cutting device for cutting a workpiece by rotating an inner peripheral blade having a hollow disk-shaped base plate and a cutting edge provided on an inner peripheral edge of the base plate,
An arrangement part for holding the work and arranging the work at a position where the work can be cut by the inner peripheral blade.
A moving part for feeding the work toward the inner peripheral blade by supporting and moving the arrangement part;
A weight connected to the moving part to pull and move the moving part by a falling movement, and a force for suppressing movement of the moving part due to the pulling of the weight to the moving part or the weight. A workpiece cutting device comprising a speed suppressing means for suppressing a moving speed of the moving portion when the blade and the cutting edge of the inner peripheral blade are in contact with each other. The speed suppressing means is
A guide bar provided with a thread groove;
Drive means for rotating the guide rod;
A restraining plate into which the guide bar is screwed and moved by rotation of the guide bar,
The restraining plate is disposed at a position that prevents movement of the moving part due to the pulling of the weight, and the restraining plate is in the same direction as the moving part at a speed slower than the moving speed of the moving part due to the pulling of the weight. The workpiece cutting device according to claim 1, wherein a moving speed of the moving unit is suppressed by moving while contacting the moving unit. The speed suppressing means is
Including a resistance member that requires a certain force to move,
2. The resistance member is disposed at a position that prevents the movement of the moving unit due to the pulling of the weight, and the moving unit moves while pressing the resistance member, thereby suppressing a moving speed of the moving unit. The workpiece cutting device described. The speed suppressing means is
A support portion for supporting the weight;
Lowering means for lowering the support part,
The lowering means suppresses the moving speed of the moving part by lowering the supporting part that supports the weight at a speed that suppresses the falling of the weight and reducing the force that pulls the moving part of the weight. The workpiece cutting device according to claim 1. A workpiece cutting method for cutting a workpiece by rotating an inner peripheral blade having a hollow disk-shaped base plate and a cutting edge provided on an inner peripheral edge of the base plate,
A step of arranging the workpiece by an arrangement portion at a position that can be cut by the inner peripheral blade;
Connecting a weight to the moving part that supports the arrangement part;
A step of moving the moving part by being pulled by the weight that is falling and moving the work toward the inner peripheral blade with the movement;
The moving speed of the moving part when at least the workpiece and the cutting edge of the rotating inner peripheral blade come into contact with each other by applying a force to the moving part or the weight to suppress the movement of the moving part due to the pulling of the weight. A workpiece cutting method comprising a step of starting cutting by suppressing the feed rate of the workpiece with respect to the inner peripheral blade.   A restraining plate is disposed at a position that prevents movement of the moving part due to the pulling of the weight, and the restraining plate moves in the same direction as the moving part at a speed slower than the moving speed of the moving part due to the pulling of the weight. The workpiece cutting method according to claim 5, wherein the moving speed of the moving unit is suppressed by moving while contacting the unit.   A resistance member that requires a certain force for movement is arranged at a position that prevents the movement of the moving part due to the pulling of the weight, and the moving part moves while pressing the resistance member, thereby suppressing the moving speed of the moving part. The work cutting method according to claim 5.   The moving speed of the moving part is suppressed by supporting the weight by a supporting part and lowering the supporting part at a speed that suppresses the falling of the weight and reducing the force pulling the moving part of the weight. Item 6. The workpiece cutting method according to Item 5.   The work cutting method according to claim 5, wherein the work is a rare earth sintered alloy. When cutting the workpiece, coolant is supplied to the cutting edge,
The coolant supplied to the blade edge is obtained by diluting a water-soluble coolant stock solution, and the coolant stock solution contains 5 wt% to 20 wt% of a surfactant and 10 wt% to 40 wt% of a lubricant. Item 10. The work cutting method according to any one of Items 9 to 9.

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