KR100365250B1 - Polishing apparatus for magnetic head and method therefor - Google Patents

Abstract

In the polishing process for forming a crown shape in a ceramic bar having a plurality of conversion units for a magnetic head, the present invention mainly relates to a ceramic bar having a plurality of grooves vertically perpendicular to a surface opposite to the surface to be polished. The elastic member made of rubber is pressed against the substantially concave polishing surface, and then the magnetic resistance of the element provided to the conversion unit of the magnetic head is measured, and based on the result of such measurement, the pressure in the crown forming operation by the closed circuit control is It provides a satisfactory shape that is well controlled by adjusting.

Description

Polishing device for magnetic head and polishing method {POLISHING APPARATUS FOR MAGNETIC HEAD AND METHOD THEREFOR}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing apparatus and method for a magnetic head for polishing a to-be-polished product composed of an array of a plurality of magnetic heads. It relates to an apparatus and a method.

The batch manufacturing process of a thin film magnetic head for use in a computer disk drive device typically includes polishing a bar-shaped ceramic (ceramic bar), which includes a plurality of thin magnetic films. The conversion units of are arranged in line on the surface, whereby the conversion unit finishes the neck height (the height of the gap) of the gap of each conversion unit to an appropriate value. The ceramic bar is cut into individual conversion units in a subsequent step, with each cut making up part of the magnetic head for use in the magnetic disk drive device. When such a magnetic head is used in a magnetic disk drive device, the ceramic portion constitutes a slider which floats on the magnetic disk by the air pressure generated by the rotation of the magnetic disk, and the conversion unit including the thin magnetic film receives the magnetic signal of the disk. A head core for recording and / or reproducing is configured.

In the above-described conversion unit, a signal recording induction magnetoelectric conversion element and a signal reading magnetoresistance (MR) element are formed. In addition, the aforementioned neck height in such a head core means the length (height) of the parts where the ends of the two magnetic poles for recording or reading the magnetic signal are opposed to each other with a very narrow gap therebetween. Such neck height magnitude is maintained at a predetermined value to enable proper recording and reading of the signal, so height accuracy is required for polishing operations.

A high accuracy polishing apparatus of a magnetic head in the form of a ceramic bar described above has already been proposed (e.g., U.S. Patent 5,620,356, etc.). In addition, the present applicant has proposed some apparatus and method (e.g., Japanese Patent Application No. 1999-162799 and the like).

As briefly described above, in the operating state of the disc drive device, the chip member (comprising the slider and the head core) at the end of the magnetic head supported by the suspension is the pressure of the airflow generated by the high speed rotation of the magnetic disk. By the thousands of microns away from the disk. In the floating state, the chip member must be kept constant in a stable position to achieve accurate information recording and reproduction on and from the magnetic disk.

For this purpose, in some magnetic heads, the surface of the chip member located at the end of the head opposite the magnetic disk is rounded or curved, resulting from the change of airflow between the inner and outer portions of the magnetic disk. The influence on the floating state of the chip member is suppressed.

In order to form such curved shapes (hereinafter referred to as crowning or crowning) in a batch process, a ceramic bar having a number of conversion units comprising a magnetic thin film is first ground to achieve the desired neck height as described above. Afterwards, crown processing is applied on the same surface to achieve the desired curved surface shape.

The aforementioned crown processing is possible by the apparatus shown in the aforementioned Japanese Patent Application No. 1999-162799. This device supports the rotating polishing table located in the horizontal direction, the workpiece to be polished (i.e., the ceramic bar having a plurality of conversion units) and holding the workpiece in a desired position in contact with the polishing table to perform polishing of the workpiece. A polishing head is provided. The polishing head is mounted on a mounting frame that is movable in the horizontal direction and the vertical direction. The polishing head is supported to be rotatable in the horizontal plane by an annular bearing on the mounting frame.

The polishing head of the apparatus shown in Japanese Patent Application No. 1999-162799 is provided with an adjusting ring at the bottom thereof. During the polishing operation, the adjusting ring contacts the polishing surface, which is the upper surface of the polishing table, thereby defining the reference surface of the position of the polishing head. The polishing head further comprises an inclined unit which makes it possible to tilt the reference system based on the adjustment ring (ie, a system composed of elements fixed to the adjustment ring) by a desired angle about a predetermined horizontal axis. Thus, the inclination unit can include an adjustment ring to tilt the reference system by a desired angle with respect to the vertical direction. The tilting operation of the tilting unit is achieved by the motor.

The apparatus further comprises means suitable for adjusting the horizontal balance of the amount of polishing by adjusting the bending or twisting of the workpiece when polishing the polishing surface of the ceramic bar constituting the workpiece. In more detail, the pressure of the workpiece applied to the polishing table is adjusted at any number of points in the longitudinal direction of the workpiece, thereby correcting the twist of the workpiece and the like and adjusting the polishing amount.

In the apparatus described above, the inclination angle of the inclination unit is fixed throughout the polishing process of the workpiece during the normal polishing operation for setting the neck height to a desired value. In addition, in such a polishing process, the polishing surface of the polishing table of the apparatus is kept perpendicular to the workpiece so that the polishing surface thereof is smoothly polished.

It is also theoretically possible by means of such a device to form a crown on the polishing surface using the warp unit provided in the device. In more detail, the polishing surface can be finished in a round shape by performing a polishing operation by gradually continuously changing the inclination angle of the inclination unit. However, crowning with such a device is difficult to provide a smooth curved surface of the desired curvature, resulting in significant fluctuations in the resulting curved surface and requires complex control of the device in such polishing operations.

For this reason, the crown processing of the polishing surface of the ceramic bar workpiece is performed in an apparatus having a polishing table having a spherical polishing surface. In one example of such a device, the ceramic bar workpiece is attached onto a rubber sheet fixed to the end surface of the rod-shaped jig, pressed by the jig to the polishing table, and the polishing operation is performed under the control of the overall pressing pressure. In another embodiment, the ceramic bar workpiece is attached to a square rod-shaped jig through a rubber sheet, and the polishing operation is performed by pressing the polishing head by its weight to the polishing surface, including the jig and the workpiece.

In summary, the conventional apparatus described above makes it possible to crown the magnetic head with high precision. In addition, the apparatus disclosed in Japanese Patent Application No. 1999-162799 cannot perform such crown processing. This is because a smooth curved surface is difficult to achieve in practice because the inclination of the inclined unit is gradually changed under complicated control.

In addition, the apparatus has a polishing table having a spherical polishing surface, wherein the processing shape achieved by polishing is usually controlled by the pressing weight and processing time of the workpiece on the polishing table, and the polishing amount is weakened, for example, of the polishing slurry. Due to the change in polishing rate resulting from this, it cannot be controlled accurately.

In view of the foregoing, it is an object of the present invention to provide a polishing apparatus and a polishing method capable of high precision crown processing of a magnetic head.

The above object is achieved by a polishing apparatus for polishing a workpiece having a plurality of magnetic heads according to the present invention, which polishing apparatus has a polishing surface constituting a part of a spherical surface having a predetermined radius of curvature. And a polishing head supported by the polishing head mounting frame, the polishing head comprising: a jig for supporting the workpiece to be polished through an elastic member; A back plate to be mounted, an elevator unit for supporting the back plate in a manner that can be raised and lowered integrally with the back plate with respect to the polishing surface and rotatable in a plane parallel to the rising and lowering direction about the support point; A plurality of correction actuator means for pressing against, the measuring means for measuring the characteristics of the magnetic head formed on the polishing surface, and the measured value It comprises adjusting means for adjusting the pressing force of the plurality of correction actuator means.

In order to achieve the above object, a preferred configuration is provided in which the elevator unit is supported by the tilting unit and the rising and lowering directions are tilted by tilting the tilting unit by the driving means for the tilting unit. Furthermore, the polishing head is preferably mounted in a rotatable manner on the polishing head mounting means. In addition, it is preferable that the polishing apparatus includes a polishing head rocking means, by which the polishing head rocking means performs the reciprocating rotational movement within a predetermined angle range.

Further, it is preferable that the plurality of correction actuator means is composed of three low friction cylinders, and the pressing portion on the back plate next to the low friction cylinder is disposed on both sides of the support point of the back plate and the aforementioned support point in the longitudinal direction of the back plate. It is preferable.

Moreover, it is preferable that the range of the above-mentioned preferable curvature radius of a grinding | polishing surface is 4-6m, and it is preferable that an elastic member is mainly made from rubber | gum. Further, the workpiece to be polished is preferably provided on a surface opposite the polishing surface with a plurality of grooves perpendicular to the longitudinal direction, and the measured characteristic of the magnetic head is preferably magnetic resistance.

The above object can also be achieved by a polishing method for polishing a workpiece having a plurality of magnetic heads according to the present invention, the polishing method comprising the steps of: supporting a workpiece by a jig through an elastic member; Moving the jig to a predetermined position relative to a rotary polishing table having a polishing surface constituting a portion of a sphere having a predetermined radius of curvature, supporting the jig rotatably in a plane substantially perpendicular to the polishing surface and supporting the jig; Lowering onto the polishing surface, and pressing the workpiece to the polishing surface through the jig to polish the workpiece, the jig can be pressed toward the polishing surface at a number of points other than the rotatable support point, The measurement of the amount of polishing based on the measurement of the characteristics of the magnetic head and the adjustment of the pressing force at multiple points based on the measurement results It is repeated several times in the polishing step.

In addition, in order to achieve the above object, in the step of supporting the workpiece to be polished by the jig, it is preferable to adjust the lowering of the jig toward the polishing surface. In addition, in the polishing step, it is preferable that the jig performs a reciprocating rotational movement within a predetermined angle range about a support point that is rotatably supported with respect to the polishing surface and is substantially parallel. Further, the pressing at the support point and the plurality of points is preferably performed by a low friction cylinder, and the plurality of pressing points are preferably located on both sides of the support point in the longitudinal direction of the jig.

Moreover, it is preferable that the range of the above-mentioned curvature radius of a grinding | polishing surface is 4-6 m, and it is preferable that an elastic member is mainly made from rubber | gum. In addition, the workpiece to be supported by the jig through the elastic member is preferably provided on the surface opposite the polishing surface with a plurality of grooves perpendicular to the longitudinal direction, and the measured characteristic of the magnetic head is magnetic resistance. It is preferable.

1 is a front view of a polishing apparatus for a magnetic head according to an embodiment of the present invention.

Figure 2 is a plan view of the polishing apparatus for a magnetic head according to an embodiment of the present invention.

Fig. 3 is a front view showing the magnetic head and the like in the polishing apparatus for the magnetic head constituting an embodiment of the present invention.

4 is a plan view of the polishing head shown in FIG.

Fig. 5 is a side view of the polishing head shown in Fig. 3;

6 is a cross sectional view of the polishing head shown in FIG. 3;

7 is a schematic perspective view showing the shape of a workpiece to be polished;

8 is a cross sectional view along the diameter of the polishing table;

9 is a block diagram of adjustment of the polishing amount in one embodiment of the present invention.

10 shows details of the measurement and multiple transmission substrate of FIG.

FIG. 11 is a view showing details of the actuator drive plate of FIG. 9; FIG.

<Description of the code | symbol about the principal part of drawing>

1: base 2: polishing table

4: driving means 6: belt

8: guide rail 10: slider

12: polishing head mounting frame

14: annular bearing 18: elastic member

20: polishing head 28, 30: pulley

44, 50, 60: shaft 46: inclined unit

52: motor 64: elevator unit

68: back plate 70A, 70B, 70C: correction actuator means

92: Finished workpiece 92a: Finished surface

94: jig 97: rubber cushion

104: ceramic bar 128: measuring pin

201: MR element 210: microcomputer

220: multiple measurement substrate 223: arithmetic unit

In the present specification, as an embodiment thereof, the polishing apparatus and method of the magnetic head of the present invention will be described with reference to Figs. 1 is a front view showing a magnetic head polishing apparatus incorporating the present invention, FIG. 2 is a plan view thereof, and FIGS. 3 to 6 are respectively a front view, a plan view, a side view and a polishing head in one embodiment of the present invention. Cross section view.

First, referring to Figures 1 and 2, the overall configuration of a polishing apparatus for a magnetic head embodying the present invention will be described. The magnetic head polishing apparatus has a base 1 for supporting the polishing table 2 in a rotatable manner on a horizontal plane, the polishing table 2 constituting a rotation drive source and being supported by the table driving means 4 supported on the base 1. Rotate through the belt (6).

A pair of vertically spaced guide rolls 8 are supported in the horizontal direction on the base 1, and the horizontally movable slider 10 is movable in the horizontal direction by a pair of guide rolls 8. You are guided. On the slider 10 which is movable in the lateral direction, the polishing head mounting frame 12 is mounted in a manner that is movable in the vertical direction (driven vertically at an arbitrarily adjustable height). The transversely movable slider 10 is driven, for example, by engaging a ball screw nut provided on the slider 10 with a ball screw nut parallel to the guide roll 8 and rotating the ball screw shaft by a motor. Whereby the slider 10 and the polishing head mounting frame 12 can perform a reciprocating linear motion.

As shown in Fig. 3, inside the polishing head mounting frame 12, the rotary support 16 is rotatably supported by the annular bearing 14, and the polishing head 20 is made of leaf spring or rubber. It is mounted on the rotary support 16 via the elastic member 18. The polishing head 20 has a bottom plate 22 and a vertical support plate 24 that are upright in parallel.

As shown in Figs. 2 and 3, the pulley 28 is fixed to the rotary support 16, and the polishing head rotating motor 32 for rotating the pulley 30 is external to the polishing head mounting frame 12. It is installed. Belt 34 connects pulleys 28 and 30. The motor 32, the pulleys 28, 30 and the belt 34 perform a function as a rocking means for causing the polishing head 20 to perform a reciprocating abduction movement (swinging motion) in a predetermined angle range.

As shown in Figs. 3 to 6, between the vertical support plates of the polishing head 20, an inclined shaft 44 parallel to the vertical support plate 24 is provided, and the inclination unit 46 is provided with a polishing head ( Articulation about the inclined shaft 44 in a way that can be inclined relative to (20).

As shown in Figs. 5 and 6, on the vertical support plate 24 of the polishing head 20, the lower part of the motor mounting base portion 48 is mounted in a rotatable manner with respect to the shaft 50, and the inclined motor ( 52 is fixed on the upper side of the motor mounting base 48. The drive shaft of the motor 52 is coupled to the ball screw shaft 54 which engages with the ball screw nut 56. The ball screw nut 56 is fixed to one end of the arm 58 and the other end of the arm is fixed on the inclined unit 46. The mechanism from the shaft 50 to the shaft 60 constitutes inclined drive means for inclining the inclined unit 46 from a state parallel to the vertical support plate 24 by a predetermined angle.

The elevator unit 64 is movably mounted vertically on the inclination unit 46 through the slide bearing (horizontal roller guide) 62. Since the movement of the elevator unit 64 in the inclined direction is performed integrally with the inclined unit 46, the elevator unit 64 and the inclined unit 46 always remain parallel to each other. The back plate 68 is articulated to the lower end of the elevator unit 64 by a shaft 66 parallel to the vertical support plate 24 and perpendicular to the inclined shaft 44.

3 to 5, correction actuator means 70A, 70B, 70C are attached to the upper side of the inclination unit 46 through the bracket 70. As shown in FIG. Correction actuator means 70A, 70B, 70C press the shaft 66 of the back plate 68 and its left and right sides downward, respectively, and serve to control the load acting on the back plate 68. In this embodiment, the correction actuator means is composed of low friction air cylinders, but other types of low friction cylinders, such as those driven by electromagnets, may be used.

The rods 80A, 80B, 80C of the correction actuator means 70A, 70B, 70C are coupled to the cylinder joints 82A, 82B, 82C whose lower ends are made of screws, nuts, spherical members, and the like, respectively, and the elevator unit ( It is possible to ascend and descend along slide bearings 84A, 84B, 84C mounted on 64. Each cylinder joint is capable of rotating about 5 ° with respect to the ascending and descending directions of the correction actuator means, thereby correcting the deviation between the cylinder joint and the axis of the correction actuator means. The lower ends of the cylinder joints 82A, 82B and 83C are connected to the left, center and right sides of the back plate 68 by connecting links 88A, 88B and 88C, respectively. Thus, as shown in these figures, the pressing forces of the correction actuator means 70A, 70B, 70C on the back plate 68 are parallel to each other.

As shown in FIG. 6, the back plate 68 is engaged with the jig 94 which is elliptical in the transverse direction by the rectangular plate 90, the fixing pin 96 and the connecting member 122. As shown in FIG. The transverse elliptical jig 94 is provided with an elastic rubber cushion 97 which is fixed, for example, with an adhesive material of epoxy resin and mainly made of rubber, on the surface opposite the polishing table 2 (lower end face in Fig. 6). do. The to-be-processed object (ceramic bar workpiece) 92 is fixed on and supported by the surface of the rubber cushion 97 opposite to the polishing table 2 by a self-adhesive function such as a rubber surface. The workpiece 92 is pressed against the polishing surface 2a of the polishing table 2 by means of a correction actuator means through the function of the above-described element, and in such a pressing state the rubber workpiece 97 is pressed by its self-adhesive function. Continue to be supported.

In the actual polishing operation, the compression load of the workpiece to be polished onto the polishing surface 2a is mainly controlled by the correction actuator means 70B, while the balance of the compression load in the longitudinal direction of the workpiece 92 is By other correction means 70B, 70C. Therefore, in accordance with the variation in the amount of polishing in the longitudinal direction of the workpiece 92, the pressing force of the correction actuator means 70A, 70B, 70C may be partially neutralized (i.e., the force in the upward direction).

For example, the polishing surface 2a of the polishing table 2, which is made of tin and is used to polish the workpiece 92, has an abrasive workpiece 92 having a predetermined round (convex) shape by a polishing process. In order to provide the to-be-polished surface 92a, it is preferable that it is formed as the recessed recessed part shape which comprises a part of spherical surface which has a predetermined radius. 8 is a cross-sectional view taken along the diameter of the polishing table 2. In this embodiment, the polishing table 2 is formed as a substantially annular shape of thick thickness, and the range of the spherical radius of which the above-mentioned concave polishing surface 2a constitutes a part is about 4 to 6 m.

In addition, when pressing the to-be-processed object 92 to the polishing surface 2a, in order to contact the to-be-polished surface 92a with the polishing surface 2a by easily bending the to-be-processed workpiece 92, On the surface of the workpiece 92 secured to the cushion 97, a plurality of grooves 92b perpendicular to the longitudinal direction of the workpiece 92 are provided. With the above-described configuration, the surface to be polished 92a is easily in contact with the substantially concave polishing surface 2a, whereby a smooth round shape can be obtained on the entire surface along the longitudinal direction of the workpiece to be polished.

As shown in Fig. 7, the workpiece 92 is composed of an elliptical ceramic bar 104 in the form of a longitudinal rod (to be cut by individual sliders of the thin film magnetic head), and a plurality of magnetic heads formed of a magnetic thin film pattern. The conversion units of are arranged in a straight array, and the magnetic thin film pattern of such conversion units is disposed on the longitudinal side 104a of the ceramic bar 104. In the present embodiment, the bottom surface (polishing surface) of the ceramic bar 104 is already polished in the preceding step, whereby each conversion unit located on the longitudinal side 104a is given a predetermined neck height.

Thus, the amount of polishing allowed to achieve the desired rounded shape should be chosen so as not to significantly change the neck height achieved in the previous step and to prevent variations in the amount of polishing of the workpiece to be processed in its longitudinal direction. The polishing step to achieve the proper neck height and the polishing step to achieve the round shape are generally carried out in separate polishing devices. Because the amount of polishing and the required accuracy of such amount of polishing vary considerably between these steps.

According to the present invention, the polishing amount on the workpiece 92 is determined by measuring the magnetoresistance value (MR value) of MR elements formed in the plurality of conversion units in the polishing process and then calculating the required polishing amount based on the measured value. It is managed by polishing under so-called closed-circuit control which obtains and adjusts the balance between the pressing force on the workpiece 92 and the predetermined polishing amount. In this embodiment, the polishing operation is performed by measuring MR values of MR elements at predetermined intervals in the conversion unit formed at the center of the ceramic bar 104 and the conversion unit formed at a predetermined position on the left and right of the ceramic bar 104. do. In this embodiment, the MR value is measured only at three positions, but when more accurate control of the amount of polishing is required, it is desirable to increase the number of measuring points and the number of pressing points on the workpiece to be polished.

In order to measure the MR value of the MR element formed in the conversion unit, an electrode electrically connected to the above-described MR element to be measured, for example, by wire bonding, is provided on the surface 94a of the transverse elliptical jig 94 opposite to the back plate. This is provided beforehand. The rectangular plate 90 is provided with, for example, a measuring pin 128 (see FIG. 3) which is deflected by a spring, so that the above-mentioned electrode and the above-mentioned electrode when the elliptical jig 94 in the transverse direction are fixed to the rectangular plate 90. The measuring pins 128 are interconnected. The measuring pin 128 is connected to an unmarked MR value measuring means and can measure the MR value of a predetermined MR element by fixing the transverse elliptical jig 94 with respect to the rectangular plate 90.

The actual configurations of the MR value measuring means and the control means of the pressing force of the actuator will be described below. FIG. 9 shows a block diagram of a control system having the above-described measuring means and control means and suitable for driving a correction actuator means based on the measured MR values, while FIG. 10 shows a measurement and multiple transmission substrate 220. Fig. 11 is a detailed block diagram of the actuator drive plate. In this embodiment, the MR value is an MR value achieved by four terminal resistance measurement, and a plurality of measuring pins 128 (POGO pins) are in contact with the MR element 201. The measurement and multiplex transmission substrate 220 converts the voltage obtained from the MR element 201 to a resistance value through the measurement pin 128 using the calculation of the four terminal resistance measurement. The resistance value thus obtained is converted into digital data, multiplexed, and enters the input / output terminal 211 of the microcomputer 210. The computer 210 calculates the amount of polishing of the workpiece 92 based on the input data and displays the amount of polishing on the operator.

The above process from MR value measurement to digital data output will be described in more detail with reference to FIG. The measurement and multiplex transmission substrate 220 performs a current supply from a constant power supply 221 and a voltage measurement between the pins and calculates numerically based on the comparison of the values measured at the calculation unit 223 and the reference resistor 222. Is executed to obtain the resistivity of the MR element. The obtained value is further converted into digital data by the A / D converter 224.

Based on the digital data after the conversion, the MR element measured on the surface to be polished 92a and the amount of polishing around it are obtained. Then, the computer 210 obtains the driving amounts required for the actuator means 70A, 70B, 70C as the data of the driving amounts, respectively, in order to achieve the required polishing amount. Then, the computer 210 supplies the data of such driving amount to the actuator driving board 230 through the input / output terminal 211, and the data of the driving amount is the A / D converter 231 of the actuator driving board. Is converted into a control signal and supplies an output current for driving the actuator means by the required amount, respectively, to the drive current output device 232 which receives the control signal. In response to such an output, the actuator means performs fine adjustment of the pressing force on the back plate 68, so that the balance of the pressure in the longitudinal direction of the workpiece 92 on the polishing surface 2a is balanced by the transverse elliptical jig ( 94).

In this embodiment, the polishing amount of the crown processing is controlled by the closed circuit described above. Therefore, it is possible to achieve fine control of the amount of polishing which is difficult to achieve in the conventional apparatus and to eliminate variations in the amount of polishing in the polishing operation. In addition, within the range of a single polishing operation, it is possible to control the polishing amount of different portions in the longitudinal direction, whereby it is possible to eliminate variations in the polishing amount in the polishing operation that are difficult to remove in the conventional apparatus.

Hereinafter, the functions and polishing methods of the embodiments of the present invention will be described.

First, the polishing head 20 shown in FIGS. 1 and 2 moves from a position opposite to the polishing table 2, and has a transverse elliptical jig having an abrasive workpiece 92 on which a plurality of thin film magnetic heads are disposed. 94 is mounted on the rectangular plate 90 of the back plate 96 by the coupling member 122 and the fixing pin 96. In this operation, the inclination angle of the back plate 68 with respect to the polishing head 20 is initially set to 0 ° (perpendicular to the reference plane 2b of the polishing table 2).

In this state, the POGO pin is in contact with a conversion unit of a predetermined magnetic head to be used for MR measurement to detect the amount of polishing or wiring coming out of such a conversion unit. POGO pins are pressed by unmarked springs to consistently achieve satisfactory electrical contact during polishing operations.

After setting the inclination angle of the back plate 68 by the inclination drive means and mounting the transverse elliptical jig 94, the polishing head mounting frame 12 with the polishing head 12 is along the guide rail 8. It linearly moves and stops at a predetermined position on the rotary polishing table 2. Then, the polishing head 20 is lowered to the polishing surface 2a constituting the upper surface of the polishing table 2. In this operation, the pressure by the correction actuator means 70A, 70C is set to zero on both sides (left and right in FIG. 3) of the shaft 66 of the back plate 68, thereby centering the shaft 66. It is possible to rotate the back plate 68 and the elliptical jig 94 in the transverse direction.

The lowering of the polishing head 20 is terminated in the state in which the workpiece 92 is in contact with the polishing surface 2a over its entire surface. As the polishing surface 2a comes in contact with the workpiece 92 at the inclined portion of the concave recess, it is necessary to tilt the workpiece 92 relative to the downward direction to bring the entire surface thereof to the polishing surface 2a. Do. As described above, in this embodiment, the back plate 68, the lateral oval jig 94 and the workpiece 92 are in contact with the surface 2a of the polishing surface in a freely rotatable state, so that the entire blood The polishing surface 2a and the polishing surface 2a can be brought into contact with each other by such rotation without using a control mechanism for tilting the workpiece 92. Further, after the lowering operation, the transverse elliptical jig 94 undergoes some up and down movement several times in order to achieve a firm contact between the entire polished surface 92a and the polishing surface 2a.

In this embodiment, since the polishing surface 2a is formed as a concave recess, even if the pressing of the workpiece 92 is achieved only by the shaft 66, the polishing surface 92a on the polishing surface 2a is formed. The pressure of the different parts may be changed as a result of the rotation of the workpiece to be polished during the polishing operation. For this reason, when the polishing head 20 is linearly reciprocated, the center of rotation of the polishing head 20 coincides with that of the workpiece 92 and such center of rotation is at or above the diameter of the polishing table 2. The configuration remaining on the extension is adopted.

The end of the lowering of the polishing head 20 is determined by detecting that a predetermined position of the polishing surface 2a approaches a predetermined value by an unmarked proximity sensor of electromagnetic capacitance type. In addition, a magnetic detection type or a distance detection type proximity sensor using a high frequency wave may be used.

Polishing of the to-be-polished surface 92a is achieved by contact of the to-be-polished surface 92a and the polishing surface 2a. During the polishing operation, the workpiece 92 is pressed onto the polishing surface 2a through an elastic rubber cushion 97, and the workpiece 92 is in its longitudinal direction to facilitate contact with the polishing surface 2a. It has a plurality of grooves 92b perpendicular to it. For this reason, the workpiece 92 is easily bent even when the shaft 66 is squeezed only by the correction actuator means 70B, whereby the pressing force is effectively spread over the entire to-be-polished surface 92a, and Variation in the amount of polishing in the workpiece to be polished relative to the polishing surface can be reduced simply by the elastic member.

However, the polishing rate and the amount of polishing depend on the contact state between the polishing surface 2a and the polished surface 92a at the start of the polishing operation and the consumption of the abrasive diamond slurry inlaid on the polishing surface 2a. It may vary in the polishing operation. In the present invention, a closed circuit control for adjusting the pressing force of the correction actuator means 70B based on the measured value and measuring the amount of polishing is adopted, whereby fine control of the amount of polishing and the amount of polishing between the different to-be-processed workpieces are adopted. It is possible to identify them. In addition, during the polishing step, the pressing force around both ends of the workpiece 92 is adjusted by the correction actuator means 70A, 70C, thereby controlling the polishing amount and simultaneously in the longitudinal direction of the workpiece. Reduces fluctuations in the amount of polishing

During the above-described polishing operation, uneven wear may occur if the same position of the workpiece 92 remains in contact with the polishing surface 2a. For this reason, the rotary support unit 16 with the polishing head 20 reciprocates by the polishing head rocking motor 32 within a predetermined angle range, and the polishing head mounting frame 12 is straight within the predetermined range. Reciprocate Therefore, during the polishing operation, the polishing head 20 executes a movement consisting of a rotary reciprocating motion and a linear reciprocating motion, thereby preventing an uneven wear of the polishing surface.

In the above embodiment, the MR value is measured at three points on the workpiece, and the load on these three points is adjusted by three correction actuator means, but the number of measurement points and the number of load points are not limited to the above. Do not. In addition, the measurement object is not limited to the MR value, for example, by measuring the change in resistance by providing an additional electrode for the workpiece to measure the amount of polishing, or by optical means such as a microscope, It is possible to obtain the amount of polishing by directly processing the shape and by applying image processing to such polished shape. Further, the correction actuator means is not limited to the low friction air cylinder employed in the above-described embodiment, and may be made of various driving means such as an electromagnet type.

The rubber cushion fixed on the transverse elliptical jig and suitable for supporting the workpiece, supports the workpiece by its adhesive or vacuum suction properties and deforms along the substantially concave polishing surface by elastic deformation. It can be composed of any material with elastic properties that can be made. Further, in the above embodiment, the deformation along the polishing surface is facilitated by providing the workpiece with a plurality of grooves perpendicular to the longitudinal direction, but such an effect is to reduce the thickness of the workpiece or to improve the workpiece. It may also be achieved by employing a resilient material. In addition, the measuring and control means is not limited to the configuration disclosed in the above-described embodiments, and may be composed of any means capable of measuring the polishing amount of the workpiece to be adjusted and adjusting the pressing force on the workpiece, based on the measured value. Can be.

According to the present invention, the workpiece is pressed into a substantially concave polishing surface through an elastic member mainly composed of rubber, and the rear surface of the workpiece is provided with a plurality of grooves perpendicular to its longitudinal direction. The entire polished surface can be easily brought into contact with the polishing surface, whereby a satisfactory crown shape can be obtained.

In addition, by controlling the amount of polishing in the crown processing through the above closed circuit control, it is possible to reduce the variation in the amount of polishing between the different workpieces generated in the conventional apparatus. It is also possible to control the amount of polishing of each part along the longitudinal direction of the workpiece within the range of a single workpiece, thereby eliminating the variation in the amount of polishing in each workpiece to be produced in the conventional apparatus. .

According to the present invention, highly accurate crown processing of the magnetic head is possible.

Claims (19)

A rotary polishing table having a polishing surface constituting a part of a spherical surface having a predetermined radius of curvature, a polishing head mounting frame provided movably with respect to the polishing surface, and a polishing head supported by the polishing head mounting frame. In the magnetic head polishing apparatus for polishing a workpiece having a plurality of magnetic heads, The polishing head may be raised and lowered integrally with the back plate with respect to the jig for supporting the workpiece, the back plate on which the jig is mounted, and the back surface with respect to the polishing surface. An elevator unit capable of supporting in a rotatable manner about a support point in a plane parallel to the descending direction, a plurality of correction actuator means for pressing the back plate to the polishing surface, and a magnetic head formed on the workpiece to be polished. And measuring means for measuring the characteristics of the control means for controlling the pressing force of the plurality of correction actuator means in accordance with the measured value. The method of claim 1, And said elevator unit is supported by an inclined unit, and said up and down directions are inclined by tilting the inclined unit with an inclined unit driving means. The method according to claim 1 or 2, And the polishing head is rotatably mounted on the polishing head mounting frame. The method of claim 3, And a polishing head rocking means for rotating and reciprocating the polishing head within a predetermined angle range. The method of claim 4, wherein And said plurality of correction actuator means are three low friction cylinders. The method of claim 5, And the low friction cylinder presses the back plate at the support point of the back plate and at both sides of the support point in the longitudinal direction of the back plate. The method according to claim 1 or 2, The range of the predetermined radius of curvature on the polishing surface is 4 to 6 meters. The method according to claim 1 or 2, And said elastic member is mainly composed of rubber. The method according to claim 1 or 2, And the workpiece is provided with a plurality of grooves on a surface opposite to the polishing surface and perpendicular to the longitudinal direction of the workpiece. The method according to claim 1 or 2, And wherein the measured characteristic of the magnetic head is a magnetoresistance. Supporting the workpiece to be worked with a jig through an elastic member, moving the jig to a predetermined position with respect to a rotary polishing table having a polishing surface constituting a part of a spherical surface having a predetermined radius of curvature, and moving the jig to Rotatably supporting the jig in a plane substantially perpendicular to the polishing surface while lowering onto the polishing surface; and pressing the polished workpiece onto the polishing surface by the jig to polish the workpiece. A magnetic head polishing method for polishing a workpiece having a plurality of magnetic heads, comprising: The jig is pressed toward the polishing surface at a number of points other than the rotatable support point, and in the polishing step, the polishing amount is measured by measuring the characteristics of the magnetic head and based on the result of the measurement, A magnetic head polishing method characterized by performing control of a pressing force on a plurality of points. The method of claim 11, The lowering of the jig toward the polishing surface is controlled in the step of supporting the workpiece to be polished by the jig. The method according to claim 11 or 12, wherein In the polishing step, the jig performs a rotary reciprocating motion within a predetermined angle range substantially parallel to the polishing surface about the support point for rotatably supporting the jig. . The method of claim 13, Crimping at said support point and said plurality of points is performed by a low friction cylinder. The method of claim 14, And said plurality of crimping points are located on both sides of said support point in the longitudinal direction of said jig. The method according to claim 11 or 12, wherein The range of the predetermined radius of curvature of the polishing surface is 4 to 6 meters, characterized in that the magnetic head polishing method. The method according to claim 11 or 12, wherein And the elastic member is mainly composed of rubber. The method according to claim 11 or 12, wherein And the workpiece to be supported by the jig through the elastic member has a plurality of grooves perpendicular to the longitudinal direction on the surface opposite the polishing surface. The method according to claim 11 or 12, wherein And wherein said measured characteristic of said magnetic head is a magnetoresistance.