JPH01179209A - Manufacture of magnetic head - Google Patents

Abstract

PURPOSE:To perform working with high accuracy by working a winding groove in parallel with a recessed groove after performing the cutting work of the recessed groove which defines regulated depth on a block, and next, forming a head block by joining integrally both blocks setting planes on which the recessed groove and the winding groove are formed as confronting planes. CONSTITUTION:On one side plane of the block 1 consisting of an almost rectangular parallelopiped magnetic material, the recessed groove is worked extending over entire length of the block so as to define the regulated depth. By integrating with the recessed groove, a winding boat form groove 4 is formed on the block 1. A winding boat form groove 12 shaped and positioned oppositely to the winding boat form groove 4 of the block 1 is formed on the other side of the block 10, and a gap material 13 having prescribed thickness (g) is attached upside the winding boat form groove 12. The blocks 1 and 10 formed in such way are pressurized contact with each other by confronting the winding boat form grooves 4 and 12, and are integrated by welding glass rods 14 and 16. By performing manufacturing in such way, the regulated depth can be secured, and the working of a magnetic head can be performed with high accuracy.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method of manufacturing a magnetic head, and is particularly suitable for use in a backup device to prevent data stored on a fixed disk of a computer from being lost. The present invention relates to a method of manufacturing a magnetic head that can be used.

<Prior Art> Magnetic heads made of sintered oxide magnetic materials such as ferrite have been widely used for recording, reproduction, and erasing in video tape recorders, cassette tape recorders, and the like.

This magnetic head is manufactured by various methods such as those described in Japanese Patent Publication No. 53-2042, Japanese Patent Publication No. 12813-1981, Japanese Patent Publication No. 6884-1984, Japanese Patent Publication No. 29403-1983, etc. .

On the other hand, as a computer-related device, preliminary recording is performed on a magnetic tape in a backup device called a streamer in order to avoid the risk of loss of recorded data in a fixed disk. For example, this backup device is capable of high-density recording of 24 trunks on a 1/2-inch wide magnetic tape, and uses a write/read/write, 2-channel, 6-gap magnetic head with a head up/down mechanism. The magnetic tape is moved step by step, and the magnetic tape is transported in an auto-reverse manner at high speed (2 m/5 ec) to back up recorded data. For this reason, the magnetic head that slides into contact with the magnetic tape at high speed is also required to have strict processing accuracy and durability.

<Problems to be Solved by the Invention> However, when attempting to wind a winding groove around a ring core manufactured by a conventional manufacturing method, reference will be made to FIG. 3 CB) later in connection with an embodiment of the present invention. As explained in
The relatively coarse grinding wheel used to cut the winding grooves may cause damage to the Dave's, resulting in a decrease in yield. Furthermore, as will be described later with reference to FIG. 3(C), even when forming predetermined dibs in a separate process after forming the winding groove, it is difficult to obtain accurate dibs, making it difficult to perform high-precision machining. There was a drawback.

This depth deficiency results in variations in the gap depth of each magnetic head, which manifests as variations in the characteristics (recording/reproduction level, resolution, phase shift, etc.) of each magnetic head.

Means for Solving the Problems> Therefore, the present invention was devised to solve the problems in the prior art, and is a recording/reproducing magnetic material particularly suitable for use in a backup device in a computer. The object of the present invention is to provide a method for manufacturing a head.

The object of the present invention is to provide a predetermined width and depth positioned to define a predetermined depth on one side of a block made of a first and/or second substantially rectangular parallelepiped magnetic material to which a winding is applied. machine a concave groove along the length of the block; after this, the winding groove for the winding is integrated with the already formed concave groove and affects the prescribed depth; The head block is formed by joining and integrating the first and second blocks using the surfaces on which the grooves and the winding grooves are formed as opposing surfaces. This is achieved by a method of manufacturing a magnetic head characterized by the following.

According to the method of the present invention having the above-described configuration, before winding grooves are processed on the contact surface of the ferrite block, grooves positioned to define and secure a specified depth are cut. Since the winding groove is cut and formed so as to partially overlap this concave groove, even if the upper end of the winding groove is damaged due to the cutting process,
Only a portion of the shape of the groove is missing, and the prescribed depth is ensured.

<Embodiment> Hereinafter, the manufacturing process of a magnetic head according to an embodiment of the method of the present invention will be explained step by step with reference to the drawings.

First, a ferrite material is cut into a predetermined rectangular parallelepiped shape and predetermined dimensions as shown in FIG. 1 to obtain an L-side ferrite block l. This cutting is performed using a device called a dicing saw by rotating its fine-toothed grinding wheel (not shown) at high speed.

Next, as shown in FIG. 2, grooves 2 of a predetermined depth (f) are formed at predetermined positions spaced apart by a predetermined depth distance (d) from the upper end of the ferrite block 1, so that the grooves 2 are arranged alternately along the entire length of the ferrite block 1. Perform cutting and depth processing. This depth machining uses the same grinding wheel 3 as used when cutting the ferrite material, and rotates it at high speed while contacting the groove cutting position of the ferrite block l, which is moved at low speed in the direction of the arrow shown in the figure. It is done by

This dibs-processed ferrite block l has
The winding boat-shaped groove and the zero surface are formed, and in this embodiment, the winding boat-shaped groove and the zero surface are processed simultaneously in the process shown in FIG. 3. This is the winding boat-shaped groove 4 and the 0 face 5.
A single grinding wheel 6 having a shape corresponding to each predetermined shape is used, and the grinding wheel 6 is rotated at a high speed and brought into contact with a ferrite block l that is moved at a low speed in the direction of the arrow shown in the figure.

Machining of the winding boat-shaped groove 4 and the zero surface 5 does not require very strict precision and requires a relatively large amount of cutting, so it is better than the grinding wheel 3 used in the process shown in Fig. 2 above. A fairly coarse grinding wheel 6 is used. In this case, conventionally, as shown in FIG. 3(B), a predetermined depth (
It has been common practice to form the winding boat-shaped groove 4 using a grinding wheel 6 having a shape corresponding to the shape of the groove so that the winding boat-shaped groove 4 is cut from a position separated by d).
According to this conventional method, since the ferrite block l is made of a brittle material, a chipped portion 4b is likely to be generated on the end face when the coarse grinding wheel 6 comes into contact with it, making it difficult to secure a predetermined depth (d). It was difficult. Therefore, in the present invention, as shown in FIGS. 2 and 3, a groove 2 is first formed by leaving a predetermined depth (d) from the upper end of the ferrite block l using a fine grinding wheel 3, and then a groove 2 of a predetermined shape is formed. A linear boat-shaped groove 4 is formed using a grinding wheel 6 so that the upper end thereof is halfway within the groove 2. Since the winding boat-shaped groove 4 is formed in this order,
As shown in FIG. 3(A), even if a defective portion 4a occurs, the groove 2 is only chipped, and the grinding is performed so that a depth machining mark 7 remains, so that it will not affect the predetermined depth (d). There is no. In this case, Fig. 3(C)
As shown in FIG. 2, the occurrence of such a defective portion is predicted in advance, and a winding boat fR4 is formed separated from the upper end of the ferrite block l by a distance (do) larger than a predetermined dibs (d), and then the second It is also conceivable that the process order is such that the groove 2 is formed using the grinding wheel 3 as shown in the figure to ensure a predetermined dibs (d), but in this case, the lower end surface 3a of the grinding wheel 3 becomes free. , the grinding wheel slides or deforms in the direction of the arrow in the figure, and the actual depth is likely to be formed slightly larger than that shown in (d), making high-precision machining difficult.

Next, as shown in FIG. 4, another grinding wheel 8 is rotated at a high speed and brought into contact with the ferrite block l which is being moved at a low speed. Machining angle θ of 6° in the direction of the arrow (first
1(A)), a plurality of track grooves 9 having a width corresponding to the width of the grinding wheel 8 are formed at predetermined intervals (1). This interval (1) becomes the track width of the magnetic herad core as a final product. This truck I! (
t) is 0.22 mm for the read head and 0.45 mm for the write head. This is to prevent output fluctuations due to track misalignment during recording and reproduction.

Thus, through the steps shown in FIGS. 1 to 4, the machining of the ferrite block l on one side (L side in this embodiment) forming the magnetic rad core is completed. The obtained L-side ferrite block 1 has a winding boat-shaped groove 4 and a surface 5 formed by processing, and a dibs processing mark 7 and a track groove 9 are formed above the winding boat-shaped groove 4 in the drawing. The other portions 1a and Ib are unprocessed planar portions.

Next, the other (R side in this embodiment) ferrite block is processed and formed, which is carried out through the steps shown in FIGS. 5 to 7. That is, after obtaining a ferrite block 10 having a predetermined shape and size in the same manner as shown in FIG. Winding boat-shaped grooves 12 at positions are cut across the entire length of the ferrite block 10. Further, as shown in FIG. 7, a gap material 13 having a predetermined thickness (g) is adhered to the uncut portion above the winding boat-shaped groove 12.

This gear gear material 13 has a high melting point (
It is made of a glass material (that does not soften at a temperature of 500° C.) and is attached to the uncut portion by an appropriate method such as sputtering or vapor deposition. This gear width (g) is 0.7μ for read/do and 1μ for write head.
．． It is said to be about 8μ. Obtained [? In the side ferrite block 10, a winding boat-shaped groove 12 is formed, an unfinished beveled surface portion 10a remains, and a gap material 13 is adhered to the upper end.

The L-side ferrite block l and the R-side ferrite block IO obtained by the above steps are butted against each other and pressed from both sides so that their winding boat-shaped grooves 4 and 12 are disposed opposite each other, as shown in FIG. . In addition, L in the same figure
The side ferrite block 1 and the R side ferrite block 10 are inverted and brought into contact with each other from the states shown in FIGS. 1 to 4 and 5 to 7, respectively.

As a result, in both ferrite blocks 1.10, the former unprocessed portion lb and the latter unprocessed portion 10a are in close contact with each other without any gaps, and the former unprocessed portion 1a is in contact with the gear 7 material 13 of the latter. A state of close contact with no gaps can be obtained. Further, as shown in the figure, an inclined groove 1 is formed between the 0 face 5 cut out in the L side ferrite block 1 and the unprocessed portion 10a of the R side ferrite block IO.
4, and a second glass rod 16 is inserted into the hollow hole or winding window 17 formed by the opposing arrangement of the winding boat-shaped grooves 4 and 12 of both ferrite blocks. do. These first and second glass rods 15 and 16 are both made of a low melting point (having a melting point sufficiently lower than 500°C) glass material whose main component is 5i02, and the ferrite blocks l and 10 are One that is sufficiently longer than the total length is used.

In this state, when the glass rods 15 and 16 are melted in an electric furnace at 500°C for about 1 hour, a molten glass material 15' is formed as shown in FIG.

16' is filled into the lower part of the inclined groove 14 and the hollow hole 17, respectively, and is then solidified to form 71 light blocks l on the L side and R side.

10 are fixedly integrated to form a head block 18. Also, although it cannot be seen from FIGS. 8 and 9 because it is hidden behind the R-side ferrite block lO, as already explained in connection with FIG.
A plurality of track grooves 9 are formed, and the glass material 16' of the molten glass rod 16 flows into each of the track grooves 9 and fills them. Incidentally, since the gap material 13 is made of a high melting point glass material, it will not be melted by the heat treatment in this electric furnace.

As shown in FIG. 9, a grinding wheel 19 is applied to the hend block 18 formed by fixing and integrating the L side and R side 7 elite broncs 1.10 with the molten glass material. Then, the winding groove 20 is formed. In the figure, the winding grooves 20 are formed on both sides of the head block 18, but in general, the winding grooves 20 are formed on both sides of the head block in the case of a read head, and only on one side of the head block in the case of a write head. Ru. According to this embodiment, the winding groove 20 is cut after the head block 18 is formed by bringing the ferrite blocks 1.10 on the L side and the R side into contact with each other. The contact surface will not be damaged by the processing jig. Therefore, the reference surface 1a of the L-side ferrite block 1 is maintained as a mirror surface without being damaged in any way.

The head block 18 that has been subjected to the winding groove processing is then cut at the center of the trunk groove 9 in an inverted state, as shown by the dotted line in FIG. 1O, to cut out a plurality of ring cores 21. Furthermore, head block 1
After cutting out a plurality of ring cores 21 from the ring core 8, the end portions on both sides do not have the specified dimensions and are therefore discarded.

The ring cores 21 thus obtained are each
It has the shape and structure as shown in the figure, that is, the end face along the cutting line A-A is filled with glass material 15' in the inclined groove 14 and in the track groove. 9 and a part of the winding window 17 are filled with a glass material 16'. Further, the cross section taken along the line B-B in FIG. 10 is as shown in FIG.
The difference is that it is done only in a part of the way. FIG. 11(C) shows a top view of the ring core 19.

Next, as shown in FIG. 12, windings 22.22 are applied between the winding grooves 4.20 and 12.20 on this ring core 21, respectively. In the illustrated embodiment, the winding is wound 30 times on each side of the ring core 21 to form a read head, but in the case of a write head, the winding groove 20 is formed only on one side as described above. For example, two wires can be bundled and wound 10 times between the winding boat-shaped grooves 4 or 12.

The ring core 21 with the winding 22 in this way is
A two-channel head assembly 23 is formed by using the two channels. This is the terminal plate groove 24 as shown in FIG.
a, 25a, 26a and a recess 24b for winding escape,
25b and 26b are formed respectively, and the ring core 21
．． Using holders 24 and 25° 26 made of ferrite material whose contact surfaces with 21 are coated with a thin layer of epoxy resin (not shown), the ring core 21 is sandwiched between each holder and brought into pressure contact. An integrated head assembly 23 is obtained by heat treatment in an electric furnace at 130° C. for 1 hour.

Next, with reference to FIG. 14, this head assembly 2
3, the terminal plate groove 24a communicates with the terminal plate groove 24a.

One end of the terminal plate 27 is fitted into 25a and 26a and fixed with epoxy resin 28. In this way, terminal board 2
7, the head assembly 23, which is a composite body, is sufficiently reinforced and firmly integrated. A predetermined pattern 27a is formed on the terminal plate 27, and the windings 22 of each ring core 21 are soldered and wired to the terminals of the predetermined pattern 27a.

The head assembly 23 is then ground to a predetermined shape and to a predetermined gap depth by a grinding wheel 29, as shown in FIG. Thereafter, the two-channel head assembly 23 with a mirror finish is completed by knopping for temporary mounting using wrapping tape (not shown).

At this point, the completed head assembly 23 can be subjected to an operation check such as a continuity test.

That is, according to this embodiment, the operation can be checked during the intermediate process of manufacturing the magnetic head, so that the product yield is greatly improved.

The base block 30 of the magnetic head is made of die-cast aluminum, for example, and is processed into the shape shown in FIG. 16. 3A is a front view of the base block 30, (B) is a rear view thereof, (C) is a bottom view thereof, and (D) is a left side view thereof. Note that the top view is the same as the bottom view except that there are no screw holes, and the right side view is the same as the left side view, so these drawings are omitted. In this embodiment, a so-called write/read/write type magnetic head is manufactured using two write head assemblies and one read head assembly as the head assembly 23 completed through the steps up to FIG. 15. Therefore, this base block 30 has a first write head assembly mounting base 31 . A read head assembly mounting base 32 and a second write head assembly mounting base 33 are formed, and these mounting bases are used for the first and second writing head assembly mounting bases, as is clear from the bottom view of FIG. 16(C). The head assembly mounts 31 and 33 are on the same level, and the read head assembly mount 32 is positioned at a level higher than this by a certain distance (h). Further, 31a, 32a, and 33a are reference planes that are parallel to each other and are used as references when mounting and attaching the respective head assemblies. The meaning of this will become clear from what will be described later.

A through window 32 is provided in the center of the read head assembly mounting table 32.
b, and recesses 31b and 33b are formed in the first and second write head assembly mounting tables 3+ and 33 on both sides, respectively, so that when the head assembly 23 is placed on these mounting tables, the recesses 31b and 33b are formed. The terminal plate 27 connects these openings 3
1b, 32b.

33b. In the diagram, 4
4 is a screw hole for attaching the base block 30 to related equipment (not shown), 34 is a step for attaching a side shield plate, and 35 is a step for attaching a bottom shield plate.

FIG. 17 shows a state in which each head assembly is attached to the base block 30 having such a shape, and a shield plate is further attached and fixed to each head assembly, similar to FIG. 16.

Each head assembly is basically similar to the head assembly 23 manufactured by the steps shown in FIGS. 1 to 15, and is a two-channel head assembly having two ring cores. More specifically, the read head assembly 37 includes the head assembly 2 shown in FIG.
3, the windings 37b are provided on both sides of the two ring cores 37a, but the first write head assembly 36 and the second write head assembly 38 have two ring cores 37a as described above. Windings 36b and 38b are provided only on one side of ring cores 36a and 38a, respectively. These first and second write hend assemblies 36.
Winding 36b at 38.

38b is formed on the side opposite the readhead assembly 37. This prevents cross-feeding (signal jumping from the write head to the read head).

These hend assemblies 36, 37, 38 are mounted on respective mounting tables 31, 32, 33 in the base block 30.
It is adhesively fixed to the top using an appropriate adhesive, and at that time, it is accurately positioned by the respective reference surfaces 31a, 32a, and 33a. This allows the head assembly 36.
The parallel relationship of 37.38 is not impaired and azimuth loss does not occur.

Shield blocks 39a, 39b; 40a, 40b; 41a, 41 made of ferrite material, which is the same material as the head assembly, are placed on both sides of each head assembly 3'6, 37.38 accurately positioned in this way.
17(A) and (C), between the shield blocks 39b and 40a and between 40b and 41.
The shape and dimensions of each shield block are determined so that gaps 42 and 43 are respectively formed between the shield block and the shield block.

Therefore, the shielding characteristics are further improved through the air layer in the gaps 42 and 43.

Also, shield books 39a, 40a, 40b.

Recesses 39c, 40c, and 41c are formed in each of the shield blocks 39a and 41b for allowing the windings 36b, 37b, and 38b of the corresponding head assembly to escape, and side end projections 39d are formed in the shield blocks 39a and 41b. , 4
1d is temporarily wrapped with wrapping tape (not shown) to give it a mirror finish.

In the figure, 36c, 37c, and 38c are each head assembly 3.
6.37.38 Terminal plate attached to opening 3
They can be seen from 1b, 32b, and 33b, respectively. Also 36d and 37d.

38d is a terminal plate mounting groove formed at the bottom of each head assembly.

As shown in FIG. 17(C), the magnetic head in this embodiment has a side end convex portion 39d of a shield block 39a, a first
a convex portion 36e approximately centered on the gap of the ring core 36a of the second write head assembly 36; a convex portion 37e approximately centered on the gap of the ring core 37a of the second write head assembly 37; It is configured to come into sliding contact with the magnetic recording/reproducing tape (T) at five locations: a convex portion 38e approximately centered on the gap and a side end convex portion 41d of the shield plate 41b.

Thereafter, the entire magnetic head is finished wrapped with a finishing lapping tape (not shown) to ensure smooth sliding contact between the entire magnetic head and the magnetic tape.

After connection cords (not shown) are soldered to each of the terminal boards 36c, 37c, and 38c, as shown in FIG.
5 and a cord extraction hole 46a opened at the bottom/
- Attach the lead plate 46 and write/read/write.
2 channels.

A 6-gear knob magnetic head is completed. The static characteristics and dynamic characteristics (DC resistance, impedance, recording/reproducing level, etc.) of this completed magnetic head are measured.

The magnetic head 5o shown in FIG. 19 has a first write/read head assembly 51 and a second write/read head assembly 52 manufactured by the method of the present invention mounted on a base block 53, and the respective heads assembly 51
．． Shield bronok 54a, 54b on both sides of 52; 55
a, 55b, and then erase it to Radcore 56
A and an erasing head 56 having an erasing gap 56b. The first and second write/read head assemblies 51.52 are formed with write rad cores 51a, 52a and read rad cores 51b, 52b, respectively. One track is recorded and reproduced, and then the write head core 52b and the read head core 5 are
1b, the second track is recorded and reproduced.
It will be easily understood that 1.52 can also be manufactured by partially changing the steps of the first embodiment as shown in FIGS. 1 to 15 described above.

Also in the magnetic head 50 shown in FIG. 19, the gap 57 is formed between the shield blocks 54b and 55a, so that the shielding characteristics are good. Further, each head assembly 51, 52 is positioned on the base block 53 while maintaining a strict parallel relationship by the reference surfaces 53a, 53b. In the figure, 51c and 52c are terminal plate mounting grooves formed at the bottom of the head assembly 51 and 52, respectively, 58 is a screw hole for mounting the base block 53, 56c is a terminal in the erasing head 56, and 59 is the erasing head 56 attached to the base. Screws for attaching to the block 53, 60 is a side shield plate, 61 is a rear shield plate, 61
Reference numeral a denotes a cord extraction hole formed in the rear shield plate, but since these are the same as those in the previously described embodiments, a detailed explanation will be omitted. This magnetic head 60 includes a side end convex portion 54b of the shield block 54a, a convex portion 51d approximately centered on the gap between the helad cores 51a and 51b of the first write/read head assembly 5I, and a second write/read head portion 51d. Head core 52a of hend assembly 52.

It is configured to come into sliding contact with the magnetic tape (T) at four locations: a convex portion 52d approximately centered on the gap 52b, and a core 56a of the erasing head 56.

<Effects of the Invention> According to the method of the present invention as explained above, a concave groove that defines prescribed dibs is first cut into a ferrite block, and then a winding groove is formed such that the upper part thereof is the lower part of the concave groove. Since it is cut so that it is fused into one,
High precision magnetic head processing is possible without chipping of dibs.

[Brief explanation of the drawing]

Figures 1 to 4 are perspective views showing each step of forming a ferrite block on one side, and Figure 3 (A)
~(C) are perspective views illustrating the process of forming a winding boat-shaped groove in the present invention in comparison with the conventional technology, and Figures 5 to 7 show each process for forming the ferrite block on the other side. FIGS. 8 and 9 are perspective views showing each process of forming winding grooves after joining both ferrite blocks by the method of the present invention, and FIG. FIG. 11 is a perspective view showing the process of cutting out a ring core, and FIG. 11 shows the obtained ring core, in which (A) is an end view thereof, (B) is a sectional view thereof, (C) is a top view thereof, and FIG. The figure is a perspective view showing a state in which this ring core is wound, and Figures 13 to 15 are perspective views showing the process of forming a two-channel head assembly using two ring cores obtained in this way. Figure 16 shows the processed shape of the base block, (A) is the front view, (B) is the back view, (C)
is a bottom view, (D) is a left side view, and Figure 17 shows the result obtained by attaching and fixing three head assemblies obtained on this base block and attaching a shield plate to each. (A) is its front view, (B) is its back view, (C) is its bottom view, and (D)
18 is a left side view of the same, and FIG. 18 shows a two-channel, six-gap magnetic head having a write/read/write head manufactured by attaching side and rear shield plates to the magnetic head. ) is a left side view thereof, (B) is a rear view thereof, FIG. 19 shows the configuration of another magnetic head that can be manufactured by the method of the present invention, and (A) is a front view thereof;
(B) is its bottom view, (C) is its rear view, (D) is its left side view, and (E) is its right side view. Explanation of symbols 1: L side ferrite block 2: Groove 3: Grinding wheel 4: Winding boat groove 5 20 faces 6: Grinding wheel 7
: Daves machining marks 8: Grinding wheel 9 Nidrak groove 10: R side ferrite block ll: Grinding wheel 12: Winding boat groove 13: Gear 7 tap material 14: Inclined groove 15, 16: Glass rod 17: Winding window 18: Head flock 19: Grinding wheel 20: Winding groove 2
1: Ring core 22: Winding wire 23: Head assembly 24, 25, 26: Holder 27 = Terminal plate 28: Epoxy resin 29: Grinding wheel 30: Base block 31. 32, 33: Head assembly mounting base 31
a, 32a, 33a: Head assembly reference plane 34
．． 35: Stepped portion 36° 38, write head assembly 3
7: Read head assembly 39a, 39b, 40a,
40b. 41a, 41b: Shield plate 42, 43: Gear 7 pin
44: Base block mounting screw hole 45: Side shield plate 46: Rear shield plate 50: Magnetic head 51.52: Write/read head assembly 53: Base block 54a.

Claims (2)

[Claims] (1) A concave groove of a predetermined width and depth positioned to define a predetermined depth is formed on one side of the first and/or second block of approximately rectangular parallelepiped magnetic material on which the winding is to be applied. Machining along the length of the block; after this, the winding groove for the winding is integrated with the already formed groove and does not affect the prescribed depth. The first and second grooves are machined parallel to the groove, and then the first and second
A method of manufacturing a magnetic head, the method comprising: forming a head block by joining and integrating blocks. (2) Using the first grinding wheel, move it relative to the block and rotate it at high speed to machine the groove, and then use the second grinding wheel to grind it against the block. 2. The method of manufacturing a magnetic head according to claim 1, wherein the winding groove is processed by rotating the wire at high speed while relatively moving the wire.