JPH06290412A - Production of magnetic head - Google Patents

Abstract

PURPOSE:To produce the magnetic head which is improved in the dimensional accuracy of a core blank material block and is improved in gap accuracy by decreasing the temp. difference between this block and a jig and lessening the warpage of the core blank material block. CONSTITUTION:The ferrite block 101 is cooled down to 23 to 25 deg.C by spending about seven hours form 120 deg.C in a thermostatic chamber after wax 3 is fused at, for example, 140 deg.C at the time of sticking the block to the jig with, the wax 3. Consequently, the block 101 and the jig 2 are eventually cooled down substantially at the equal temp., thereby the warpage of the block 101 after the cooling is drastically lessened and a recess in the central part is drastically decreased to, for example, 0.5 to 1.5mum as compared with both ends. The state of the surface (surface to be mirror-finished) of the block 101 after the cooling becomes smoother than that before the cooling. Then, the variations in the gap accuracy in the longitudinal direction of the block are decreased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a magnetic head.

[0002]

2. Description of the Related Art Conventionally, as a magnetic head for, for example, a floppy disk, there is one having a structure as shown in FIGS. 16 to 19 (here, for 4 MB).

This magnetic head is shown as a composite head.
As shown in FIGS. 16 and 17, a main core 23 having a recording / reproducing magnetic gap G1 and an erasing magnetic gap G2;
Character-shaped auxiliary core (back core) 26 and drive coil 24
A magnetic circuit portion is constituted by a pair of coil bobbins 24 and 25 around which a and 25a are wound. And the main core 23 is
A pair of sliders 20 and 22 sandwich and fix the slider in order to secure the contact characteristics with the floppy disk.

The main core 23 and the auxiliary core 26 are
The coil bobbins 24 and 25 are joined to each other, and are pressed and supported by a U-shaped metal leaf spring 27 to form a magnetic coupling. These head components are housed in the magnetic shield member 28 after being assembled.

The magnetic head 29 thus configured
Is temporarily fixed to a predetermined position on the head mounting surface of the gimbal 30 with an instant adhesive. The magnetic head 29 is coated with an ultraviolet curable resin 32 between the side wall surfaces of the sliders 20 and 22 and the head mounting surface to be adhesively reinforced, and then covered with a magnetic shield member 28, both of which are gimbaled by the resin 32. Fixed at 30.

The gimbal 30 having the magnetic head 29 mounted thereon is further coupled to a flexible printed circuit 41 which is a head supporting member. Thus, as shown in FIG. 19, the magnetic head assembly having the magnetic head 29 is attached to a carriage 62 of a floppy disk drive main body (not shown) and a movable arm rotatably attached to the carriage 62 in the arrow X direction in the figure. 63 and these carriages 62,
Magnetic heads 29 respectively provided on the tip side of the movable arm 63,
The recording / reproducing is performed on both sides of the floppy disk 42 by 29. By the pivots 64 and 65, the contact state of the magnetic head 29 with the disk 42 is always kept constant.

By the way, the main core (head chip) 23 as shown in FIG. 16 is manufactured through the steps shown in FIGS. That is, first, the core material block 1 is attached to the jig 2 as shown in FIGS.

At this time, the core material block 1 is made of ferrite, the jig 2 is made of high speed tool steel (for example, SKD-11 material), and the wax 3 is used to attach the block 1. This wax is heated to 140 ° C and melted to be interposed between the block 1 and the jig 2, and usually 120 ° C to 23 to 25 ° C.
The wax is solidified by natural cooling in about 1 hour until the block 1 is fixed to the jig 2.

However, in this case, the cooling rates of the block 1 and the jig 2 are not constant, and the block 1 is likely to be cooled due to the fact that the block 1 is on the front surface side and its material.
As a result, as exaggeratedly shown in FIG.
(Similarly) After cooling, the block 1 warps in the length direction, and is stuck on the jig 2 in this state.

FIG. 20 shows the temperature change between the jig and the work (block) after the start of cooling. It can be seen that the temperature difference between the jig and the work (block) tends to become large because of the rapid cooling.

Therefore, the state of the surface (the surface to be mirror-finished) of the block 1 after cooling is more than that before cooling by using, for example, a stylus type surface roughness meter (Surfcom manufactured by Tokyo Seimitsu Co., Ltd .; hereinafter the same). As a result of measurement, as exaggeratedly shown in FIGS. 20 and 21, both end sides warp upward in the block length direction,
A dent of 4 to 5 μm occurs.

Next, the block 1 is ground as shown in FIG. 23 to obtain two blocks 1 from each block.
A and 1B are cut out, a plurality of grooves 4 are put in parallel in the block 1A in the length direction, and a large number of grooves 5 for forming a magnetic gap are formed in both blocks 1A and 1B at right angles to the grooves 4. Put in parallel.

However, after the grooving process, the surfaces of the blocks are lapped to be mirror-finished and further removed from the jig 2, as shown in FIG. And causes variations in thickness. This is because the block 1 has already been warped at the stage of FIG. 22, and grooving and lapping are performed as they are.

The blocks 1A and 1B having such variations in thickness are next vapor-deposited with a gap spacer such as SiO _{2 on the} gap-opposing surface, and then primary tracks are aligned as shown in FIG. They are joined and integrated with each other (not shown) (primary fusion).

At the time of this primary fusion bonding, both blocks 1A
And 1B are brought into contact with each other on the side facing the gap, and a fusion-bonding glass rod (not shown) is inserted into the groove 4 while applying pressure from both sides by using the fusion-bonding jig 6, and is heated and melted. Cooling.

However, the blocks 1A and 1B, which already have variations in thickness at the stage of FIG. 23, are not corrected even in the primary fusion step of FIG.
The distance between the -1Bs is widened as if they were separated from each other. This results in variations in the gap length in the block length direction, as will be described later.

As shown in FIG. 25, the block 1 is kept in the state where the distance between the two blocks is changed in the lengthwise direction.
A pair of B centered and processed into a thin center core 1B is manufactured, and these are secondarily fused with a center glass (not shown).

Further, this fused body is divided into two as shown in FIG. 26 and sliced into individual head chips 23 as shown in FIG. These head chips 23 correspond to the slider 20-
It is clamped and fixed between 22 and finally ground by the grinding process.
6, processed into the shape shown in FIG.

Each head chip 23 is manufactured as described above. However, as described with reference to FIG. 24, since the intervals between the blocks 1A-1B have already varied in the lengthwise direction, as shown in FIG. The gap length changes along the length direction,
In particular, the gap length is remarkably expanded at both ends of the insulating film (gap spacer) despite the fact that the insulating film is thin. With this, as shown in FIG. 28, the gap length varies between the head chips 23 that are individually cut out (especially, the gap length becomes larger toward both ends shown by arrows), and the electromagnetic conversion characteristics become unstable.

[0020]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for improving the dimensional accuracy of a block, improving and stabilizing the gap accuracy, and manufacturing a head having good and stable electromagnetic conversion characteristics. .

[0021]

That is, according to the present invention, a core material block (for example, a ferrite block) to be processed in a magnetic head is fixed to a jig (for example, hardened steel) by a bonding material (for example, wax). In a method of manufacturing a magnetic head, the bonding material is arranged between the core material block and the jig in a temperature rising state, and the core material block and the jig are cooled from this state at an equal speed. It is related. Here, the above-mentioned "equivalent speed" also means a speed that does not have to be completely the same speed but may have some difference within a range in which the warp of the core material block can be sufficiently reduced.

In the present invention, in order to effectively suppress the variation in cooling rate, it is desirable to cool the core material block and the jig relatively slowly in the constant temperature bath at an average rate of 0.2 ° C./min.

[0023]

EXAMPLES Examples of the present invention will be described below.

According to this embodiment, the ferrite block 10
When 1 is attached to the jig (for example, hardened steel such as SKD-11 material) 2 with the wax 3, the following effective method is adopted.

That is, as shown in FIGS. 1 and 2, the jig 2
When pasting the block (work) 101 with wax 3 to the above, after wax 3 is fused at 140 ° C, the temperature is changed from 120 ° C to 23-25 ° C in a constant temperature bath (not shown) for about 7 hours. Cooling. This cooling rate should be about 0.2 ° C / min on average.

As a result, the block 101 and the jig 2 can be cooled at substantially the same rate, and the temperature difference between them can be significantly reduced. Therefore, although the block 101 exists on the surface side, the temperature is lowered at the same temperature as the jig 2, and the warp of the block 101 after cooling is extremely small as shown in FIGS. 1 and 2. The central depression is 0.5 to 1.5 μm, which is significantly reduced from both ends. The state of the surface (surface to be mirror-finished) of the block 101 after cooling is as shown in FIG. 1 by a stylus type surface roughness meter, as compared with that before cooling.

As a result, variations in the gap length in the block length direction are significantly reduced in the manufacture of the magnetic head. This will be described along with the head manufacturing process shown in FIGS.

First, the ferrite block 101 shown in FIG.
And a plurality of them are fixed on the jig 2 made of hardened steel with wax as shown in FIG. At this time, as described above, since the block 101 is gradually cooled from 120 ° C in the thermostat at an average rate of 0.2 ° C / min, the block 101 warps (deforms) on the jig 2.
Hardly occurs.

Next, the block 101 is ground as shown in FIG. 6 to obtain one block from each block.
101A and 101B are cut out, and a plurality of grooves 4 are formed in the block 101A in parallel in the length direction.

Next, as shown in FIG. 7, both blocks 101A are
A large number of grooves 5 for forming a magnetic gap are formed in parallel with each other in 101B and orthogonal to the grooves 4.

After the grooving process, the surface of each block is lapped to be mirror-finished and further removed from the jig 2, as shown in FIG.
B has a substantially uniform thickness in its length direction, as shown in FIG.
There is no thickness variation as shown in.

Next, the blocks 101A and 101B are subjected to primary track alignment as shown in FIG. 9 after vapor deposition of a gap spacer such as SiO ₂ on the gap facing surface, and bonded to each other by a fusion glass (not shown), Integrate (primary fusion).

At the time of this primary fusion bonding, both blocks 101
A and 101B are brought into contact with each other on the side facing the gap, and a fusion-bonding glass rod (not shown) is inserted into the groove 4 while applying pressure from both sides using a fusion-bonding jig (see FIG. 24), Heat melt,
Cool further.

In this case, the blocks 101A and 101B are
Since there is no warpage and there is no variation in thickness, the distance between the blocks 101A and 101B (that is, the gap length in the block length direction) is maintained substantially constant even after fusion bonding.

Then, as shown in FIG. 10, the block 101B is ground to form a thin center core 101B.

Then, a pair of blocks shown in FIG. 10 is produced as shown in FIG. 11, and these are secondarily fused with a center glass (not shown) as shown in FIG.

Next, this fused body is divided into two as shown in FIG. 13, and further, as shown in FIG. 14 and FIG.
Slice into 123. These head chips 123 are sandwiched and fixed between the sliders 20-22 described above, and finally processed into the shape shown in FIGS. 16 and 17 by grinding.

The head chips 123 of the composite magnetic head are manufactured as described above. Since the distance between the blocks 1A-1B is kept substantially constant in the length direction,
As shown in FIG. 3, the gap length becomes substantially constant along the length direction. In this case, since the insulating film (gap spacer) is thin at both ends of the block, the gap length is small, but the gap length as a whole is almost constant in the block length direction, and there is no problem. The gap length is substantially uniform between the head chips 123 cut out individually, and the electromagnetic conversion characteristics thereof are constant.

Although the embodiments of the present invention have been described above, the above embodiments can be further modified based on the technical idea of the present invention.

For example, the cooling rate at the time of sticking the above-mentioned block can be variously controlled, and the control method can use means other than the constant temperature bath.

Further, the materials, shapes and the like of the blocks, the bonding materials and the jigs described above may be changed.

For example, the present invention is for a floppy disk of 2 MB, a floppy disk of another size,
Alternatively, it can be applied to a head for a magnetic recording medium other than a floppy disk.

[0043]

As described above, according to the present invention, when the core material block is fixed to the jig by the joining material, the joining material is arranged between the core material block and the jig in a temperature rising state, and from this state Since the core material block and the jig are cooled at the same speed, it is possible to reduce the temperature difference between the core material block and the jig, and prevent or reduce the warp of the core material block.

As a result, it is possible to improve the dimensional accuracy of the block, improve and stabilize the gap accuracy, and manufacture a head having good and stable electromagnetic conversion characteristics.

[Brief description of drawings]

FIG. 1 is a graph showing a comparison of cooling temperatures of a block and a jig when manufacturing a composite magnetic head for a floppy disk according to an example of the present invention.

FIG. 2 is a schematic view showing a jig-block and a block surface state before and after the cooling.

FIG. 3 is a graph showing changes in gap length in the length direction of the block.

FIG. 4 is a perspective view showing one process step in manufacturing the magnetic head.

FIG. 5 is a perspective view showing another process step of manufacturing the magnetic head.

FIG. 6 is a perspective view showing another process step of manufacturing the magnetic head.

FIG. 7 is a perspective view showing another process step of manufacturing the magnetic head.

FIG. 8 is a perspective view showing another process step of manufacturing the magnetic head.

FIG. 9 is a perspective view showing another process step of manufacturing the magnetic head.

FIG. 10 is a perspective view showing another process step of manufacturing the magnetic head.

FIG. 11 is a perspective view showing another process step of manufacturing the magnetic head.

FIG. 12 is a perspective view showing another process step of manufacturing the magnetic head.

FIG. 13 is a perspective view showing another process step of manufacturing the magnetic head.

FIG. 14 is a perspective view showing still another process step at the time of manufacturing the same magnetic head.

FIG. 15 is a perspective view showing a head chip cut out when the magnetic head is manufactured.

FIG. 16 is a perspective view showing a head chip of a conventional floppy disk magnetic head.

FIG. 17 is an exploded perspective view of the magnetic head.

FIG. 18 is a perspective view of the magnetic head attached to a gimbal and a flexible printed circuit.

FIG. 19 is a schematic cross-sectional front view showing a usage state of the magnetic head.

FIG. 20 is a graph showing a comparison of cooling temperatures of a block and a jig when manufacturing a composite magnetic head for a floppy disk according to a conventional example.

FIG. 21 is a schematic diagram showing a jig-block and a block surface state before and after the cooling.

FIG. 22 is a perspective view showing one process step in manufacturing the same magnetic head.

23A and 23B are a schematic front view and a perspective view showing another process step in manufacturing the same magnetic head.

24A and 24B are a schematic front view and a perspective view showing another process step of manufacturing the magnetic head.

FIG. 25 is a perspective view showing another process step of manufacturing the magnetic head.

FIG. 26 is a perspective view showing another process step of manufacturing the magnetic head.

FIG. 27 is a graph showing a change in gap length in the length direction of the block.

FIG. 28 is a perspective view showing still another process step during manufacturing of the magnetic head.

[Explanation of reference numerals] 1, 1A, 1B, 101, 101A, 101B ... Ferrite block or core 2 ... Jig 3 ... Wax 4, 5 ... Groove 23, 123 ... Head chip 29 ... Magnetic heads

Claims (3)

[Claims] 1. When fixing a core material block to be processed into a magnetic head to a jig with a bonding material, the bonding material is arranged between the core material block and the jig in a temperature rising state. A method of manufacturing a magnetic head, wherein the core material block and the jig are cooled from a state at an equal speed. 2. The manufacturing method according to claim 1, wherein the core material block and the jig are cooled in a constant temperature bath at an average rate of 0.2 ° C./min. 3. The manufacturing method according to claim 1, wherein the core material block is formed of ferrite, the jig is formed of hardened steel, and wax is used as a joining material.