JPH07272206A - Production of magnetic head - Google Patents

Abstract

PURPOSE:To improve head output and to stabilize dimensional accuracy without lowering the magnetic permeability of magnetic metallic layers by using a grinding wheel formed by using grains having an average grain size of a prescribed mum range in cutting magnetic core half bodies integrated by joining. CONSTITUTION:A dummy substrate 4 formed by inserting the magnetic metallic films 3 between a pair of substrates 1 and 2 is produced. Opposite side faces 4a, 4b on which the magnetic metallic films of thus dummy substrate 4 are exposed are subjected to various kinds of cutting and the surface condition after the working is visually observed and the magnetic permeability of the magnetic metallic films 3 is measured. Samples are obtd. by using the diamond grinding wheel which is formed by using the diamond abrasive grains having an average grain size of 2 to 6mum in cutting, rotating this grinding wheel at a spec of >=2000 to <=5000mm/min and feeding the dummy substrate at a feed speed of >=20m/min to <=80m/min. Consequently, the insulating layers of the cut surfaces are more hardly failed than the samples formed by using the abrasive grains varied in grain sizes. Magnetic insulation is thus assured and the magnetic permeability of the magnetic metallic films is improved.

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 used in a video tape recorder or the like, and in particular, a pair of magnetic core halves each having a metallic magnetic film sandwiched between a pair of substrates are joined and integrated. The present invention relates to a so-called laminated type magnetic head manufacturing method.

[0002]

2. Description of the Related Art In recent years, video tape recorders (hereinafter referred to as
Called VTR. 1) to 5 μm in thickness as a magnetic head that can be used for high density recording and reproduction.
A magnetic head using a magnetic metal film, in which a magnetic metal thin film having a thickness of about 100 to 200 nm and an insulating film having a thickness of 100 to 200 nm are alternately laminated, is put to practical use. As the magnetic head, a pair of magnetic core halves in which a metal magnetic film which is the above-mentioned laminated magnetic film is sandwiched between a non-magnetic substrate such as ceramics and crystallized glass or a magnetic substrate such as magnetic ferrite is used. There is known a so-called laminate type magnetic head that is joined and integrated by abutting.

In the laminate type magnetic head as described above, JP-A-4-225281, JP-A-5-203135, or JP-A-5-22 is used.
As disclosed in Japanese Patent No. 56899, uneven wear on a sliding surface of a magnetic recording medium of a metal magnetic film caused by a difference in wear resistance between a substrate constituent material and a metal magnetic film constituent material is prevented, and a reduction in output of a magnetic head is prevented. Alternatively, for the purpose of improving the wear resistance of the magnetic head, there has been proposed a magnetic head in which a metal magnetic film is provided so as to be obliquely continuous in the sliding direction of the magnetic recording medium.

The magnetic head as described above is manufactured as follows. First, a plurality of substrates on which a metal magnetic film is formed are laminated so that the substrates and the metal magnetic films are alternately arranged to form a pair of magnetic core half blocks. And
The pair of magnetic core half blocks are joined and integrated so that the end faces of the metal magnetic films are butted against each other. Next, the magnetic core half block integrated and joined is cut at a position intersecting the extending direction of the metal magnetic film at a predetermined angle and divided into magnetic heads to complete a magnetic head. That is, the formed magnetic head has the metal magnetic film exposed on the cut surface.

[0005]

However, the magnetic head manufactured as described above has a disadvantage that the head output is not very good.

In the method of manufacturing a magnetic head as described above, the magnetic core half blocks joined and integrated as described above are cut at a position intersecting the metal magnetic film extending direction at a predetermined angle. Then, it is divided for each magnetic head whose metal magnetic film is exposed on the cut surface. That is, a part of the metal magnetic film is also cut. At this time, the cutting is generally performed using a diamond grindstone using diamond abrasive grains having an average particle diameter of 20 to 30 μm. However, when cutting with such a grindstone, the cut surface becomes very rough. Therefore, in order to improve the magnetic permeability of the metal magnetic film, the insulation provided between the magnetic metal thin films is improved. The membrane breaks at the cut surface. As a result, the magnetic insulation of the metal magnetic film is destroyed, the eddy current loss in the metal magnetic film is increased, the magnetic permeability in the metal magnetic film is significantly reduced, and the head output of the manufactured magnetic head is increased. Is not very good.

Therefore, a method has been proposed in which the cut surface is polished by a method such as polishing to remove the damaged insulating film on the cut surface to secure the head output of the magnetic head manufactured. However, when polishing is performed after cutting in this manner, the number of manufacturing steps is increased, and the polishing process is a complicated operation, so that productivity is reduced.

Further, when polishing is performed by a method such as polishing as described above, it is difficult to control the polishing depth and the variation of the attachment height when attaching the magnetic head to the polishing jig. The distance from the polished surface of the manufactured magnetic head to the gap edge varies, which reduces the manufacturing yield and lowers the productivity. Furthermore, the magnetic head may be damaged when it is attached to or removed from the polishing apparatus, which reduces the manufacturing yield and the productivity.

By the way, when the magnetic head manufactured as described above is mounted on a VTR, one magnetic head having different azimuth angles of the magnetic gaps is mounted on the drum.
Install facing each other at 80 °. At this time, in a pair of magnetic heads attached to the same drum, the distance in the track width direction from the magnetic head mounting surface of the drum to the edge of the magnetic gap of the magnetic head, so-called track height difference is generally within 2 to 3 μm. Is said to be preferable.
And when mounted on the same drum as described above,
The probability of obtaining a pair of magnetic heads having a track height difference of 2 to 3 μm or less is called a pair yield.

However, in the magnetic head manufactured as described above, the distance from the polished surface to the gap edge varies, and when such a magnetic head is mounted on the drum, the track height accuracy is It depends on two factors, that is, the variation of the track height of the magnetic head itself (the distance from the polished surface to the gap edge) and the variation of the height of the magnetic head mounting surface of the drum facing each other by 180 °. The pair yield is low.

Therefore, the present invention has been proposed in view of the conventional circumstances, and the magnetic core half blocks integrally joined together are cut by cutting each magnetic head without lowering the magnetic permeability of the metal magnetic layer. It is possible to manufacture a magnetic head having good head output and stable dimensional accuracy by cutting a magnetic core half body that is divided into or integrated with each other to form a magnetic head. Yield is good,
It is an object of the present invention to provide a method of manufacturing a magnetic head which can improve productivity.

[0012]

Means for Solving the Problems As a result of intensive studies made by the present inventors in order to achieve the above object, as a result of use in a grindstone when cutting a magnetic core half block or a magnetic core half body integrated and joined. It was found that the damage of the insulating film in the metal magnetic film on the cut surface can be prevented by defining the grain size of the abrasive grains to be formed. It has also been found that the damage to the insulating film as described above can be further prevented by defining the rotational speed of the grindstone and the feed speed of the magnetic core half block or the magnetic core half that is the object to be cut. The grain size of the abrasive grains used in the grindstone, the rotation speed of the grindstone, and the feed speed of the magnetic core half block or magnetic core half of the object to be cut are such that the brittle fracture of ferrite generally used as a substrate is substantially It has also been found that it is preferable to set the range to be a ductile mode in which plastic flow that does not accompany is applied.

That is, according to the present invention, a pair of magnetic core halves, in which a metal magnetic film is sandwiched between a pair of substrates in the film thickness direction, are joined and integrated so that the end faces of the respective metal magnetic films are butted against each other. After that, the magnetic core halves that have been joined and integrated are cut at a position that intersects with the extending direction of the metal magnetic film at a predetermined angle, and a magnetic head in which the metal magnetic film is exposed on the cut surface is formed. In the method of manufacturing a magnetic head to be formed, cutting of the magnetic core halves integrally joined and bonded is performed by using a grindstone using abrasive grains having an average grain size of 2 μm or more and 6 μm or less. is there.

In the method of manufacturing the magnetic head of the present invention,
If the average grain size of the abrasive grains used in the grindstone is less than 2 μm, the cutting speed becomes too slow and the grindstone is likely to be clogged. On the other hand, if the average grain size of the abrasive grains is larger than 6 μm, the ferrite is out of the ductility mode, and the insulating layer of the metal magnetic film is damaged. The grain size of the grindstone is 6
The presence of particles larger than μm makes it difficult to cut the ferrite in the ductile mode. Therefore, it is preferable to use a grindstone having a maximum particle size of 6 μm or less. Further, in order to make the surface roughness of the cut surface uniform, it is preferable to use a grindstone having an average particle diameter in the above range and having a particle diameter as uniform as possible.

Further, the above-mentioned grindstone contains the above-mentioned abrasive grains.
It can be obtained by bonding with a metal-based bond such as metal sintering, metal resin or electroforming. As the above-mentioned metal bond, it is generally preferable to use a metal-based bond having N-hardness as indicated by a grindstone, though it varies depending on the property of the material to be cut. The degree of concentration of abrasive grains varies depending on the nature of the material to be cut, etc., but is generally preferably about 100. However, the hardness of the metal bond or the degree of concentration of the abrasive grains is not limited to the above range.

Further, in the method of manufacturing a magnetic head of the present invention, the rotational speed of the grindstone at the time of cutting the magnetic core half body integrated and joined is 2000 m / min or more and 5000 m / min or more.
It is preferable that the feed rate of the magnetic core halves joined and integrated is 20 mm / min or more and 80 mm / min or less.

The rotational speed of the grindstone is out of the above range,
Alternatively, if the feeding speed of the magnetic core halves integrally joined is out of the above range, the ferrite core is out of the ductility mode, and the insulating layer of the metal magnetic film is easily damaged, which is not preferable.

Further, in the method of manufacturing a magnetic head of the present invention, it is preferable to use diamond abrasive grains or cubic boron nitride abrasive grains as the abrasive grains used for the grindstone.

[0019]

In the method of manufacturing a magnetic head of the present invention, the magnetic core halves integrally joined so that the end faces of the metal magnetic film are butted against each other are intersected at a predetermined angle with respect to the extending direction of the metal magnetic film. When cutting at any position, the average particle size is 2μ
Since the grindstone using the abrasive grains of m or more and 6 μm or less is used, the insulating layer in the metal magnetic film on the cut surface is unlikely to be damaged. At this time, the rotation speed of the grindstone was set to 2000 m / mi.
If the feeding speed of the magnetic core halves joined and integrated is 20 mm / min or more and 80 mm / min or less, the insulating layer is less likely to be damaged. Further, in the method of manufacturing a magnetic head of the present invention, since the cut surface of the magnetic head is not subjected to polishing or the like, the distance from the cut surface of the magnetic head to the gap edge is less likely to vary, and the dimensional accuracy is stable. A magnetic head is formed.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments to which the present invention is applied will be described in detail below with reference to the drawings.

Experimental Example 1 First, the relationship between the cutting method and the magnetic permeability of the metal magnetic film was investigated. That is, the pair of substrates 1 and 2 as shown in FIG.
A dummy substrate 4 in which the metal magnetic film 3 is sandwiched by is produced, various side faces 4a and 4b of the dummy substrate 4 which are exposed to each other are subjected to various cutting processes, and the side faces 4a and 4b after the process are performed. The surface condition of the above was visually observed, and the magnetic permeability of the metal magnetic film 3 was measured. It should be noted that crystallized glass is used for the substrates 1 and 2 and 3 for the metal magnetic film 3.
A magnetic metal thin film made of sendust with a thickness of μm is 0.2
Five layers were used with an insulating film made of SiO _{2 having} a thickness of μm interposed therebetween.

Then, the cutting process is performed so that the average particle size is 2 to 6 μm.
Using a diamond grindstone using m diamond abrasive grains, the above grindstone is 2000 m / min or more, 5000 m
Sample 1 was a dummy substrate that was rotated at a speed of / min or less and sent out a dummy substrate that is an object to be cut at a feed rate of 20 mm / min or more and 80 mm / min or less.

Further, a diamond grindstone containing diamond abrasive grains having an average particle size of 20 to 30 μm was used, and the cutting speed was changed in the same manner as in Sample 1, and the cutting speed was changed. A dummy substrate obtained by polishing was used as Sample 2.

The polishing is performed by a device as shown in FIG. That is, first, a dummy substrate (not shown), which is a workpiece, is attached to the polishing jig 5 with an adhesive such as wax so that the processed surface of the dummy substrate faces the processed surface 5a of the polishing jig 5. Further, the processing surface 5a of the polishing jig 5 is the polishing surface plate 7
The polishing jig 5 is attached to the holding device 6 which is rotatable in the M ₁ direction in the figure so as to come into contact with the polishing surface 7 a. The polishing surface 7a of the polishing platen 7 is made of tin, and a polishing liquid containing diamond abrasive grains having an average particle diameter of 1 μm is supplied to the polishing surface 7a. And polishing surface plate 7
Is rotated in the direction of the arrow M ₂ in the drawing, and the holding device 6
Is rotated in the direction M ₁ in the figure. As a result, the polishing jig 5 rotates in the direction of the arrow M ₃ in the figure, and the processed surface of the dummy substrate, which is the workpiece attached to the polishing jig 5, is polished by the diamond abrasive grains in the polishing liquid.

Further, using a diamond grindstone containing diamond abrasive grains having an average particle size of 20 to 30 μm, a dummy substrate cut and processed in the same manner as in Sample 1 at the rotational speed of the grindstone and the feeding speed of the dummy substrate is used as a sample. It was set to 3.

Observation of the surface state of the side surfaces 4a, 4b of the cut samples 1 to 3 revealed that the samples 1 and 2 were smooth. On the other hand, in Sample 3, the surface was rough.

The results of measuring the magnetic permeability of the metal magnetic films of Samples 1 to 3 are shown in FIG. In the figure, the horizontal axis represents frequency and the vertical axis represents magnetic permeability. The solid line in the figure is sample 1.
And the results of Sample 2 are shown, and the alternate long and short dash line in the figure shows the result of Sample 3.

As can be seen from FIG. 3, the sample 1 is
After the cutting process, the damaged portion of the insulating layer in the metal magnetic film on the cut surface was removed by polishing to show magnetic permeability equivalent to that of Sample 2 in which magnetic insulation was secured. On the other hand, in Sample 3, the grain size of the abrasive grains used for the grindstone is large,
It was confirmed that the cut surface becomes a surface having a rough surface, so that the insulating layer in the metal magnetic film on the cut surface was damaged, and the magnetic permeability of the metal magnetic film was significantly reduced.

That is, when the cutting process as in Sample 1 is performed using a diamond grindstone using diamond abrasive grains having an average particle size of 2 to 6 μm, the insulating layer in the metal magnetic film on the cut surface is less likely to be damaged. It was confirmed that the magnetic permeability of the metal magnetic film was good because magnetic insulation was ensured.

Further, when the diamond grindstone used for cutting the sample 1 was used to perform cutting by changing the rotation speed of the grindstone and the feed speed of the dummy substrate which is the object to be cut, the rotation speed of the grindstone was found to be Out of the range of 2000 m / min or more and 5000 m / min or less, or the feed rate of the dummy substrate is 20 mm / min or more, 80 mm
It has been confirmed that when the ratio is out of the range of / min or less, the coarse polishing powder causes damage to the insulating layer in the metal magnetic film on the cut surface, and the magnetic permeability of the metal magnetic film is significantly reduced.

That is, in Sample 1, the cutting process was performed at a rotational speed of the grindstone of 2000 m / min or more and 500
Since the cutting speed is set to 0 m / min or less and the feed rate of the dummy substrate, which is the object to be cut, is set to 20 mm / min or more and 80 mm / min or less, the insulating layer is less likely to be damaged, and the magnetic permeability of the metal magnetic film is reduced. Is good.

Experimental Example 2 Next, according to the various cutting methods described in Experimental Example 1, the magnetic core half body joined and integrated was cut to manufacture a magnetic head.
The head output of these magnetic heads was measured. In this experimental example, the magnetic core half blocks were joined and integrated, then cut, and divided into magnetic heads for manufacture.

In the magnetic head manufactured in this experimental example, as shown in FIGS. 4 and 5, the metal magnetic films 11 and 12 are arranged in the first substrate 13, 14 and the second substrate 15, 16 in the film thickness direction.
A pair of magnetic core halves 17, 1 sandwiched by
The magnetic core halves 17 and 18 are joined and integrated by a fused glass 19 so that the metal magnetic films 11 and 12 are abutted against each other. At this time, the metal magnetic films 11 and 12 are arranged so as to be continuous in a substantially straight line obliquely intersecting with the medium sliding direction indicated by an arrow M at an angle θ ₁ . Then, the metal magnetic film 1
Between the abutting surfaces of 1 and 12, a predetermined azimuth angle θ
₂ , a magnetic gap g having a track width Tw (13 μm in this experimental example) is formed.

As described above, the magnetic core halves 17 and 18 are
Metal magnetic films 11 and 12 to be main cores, and first and second substrates 13 and 14 and 15 and 1 sandwiching the metal magnetic films 11 and 12 from the thickness direction.
The first substrates 13 and 14 are laminated so as to sandwich the metal magnetic films 11 and 12 formed on the first main surface of the second substrates 15 and 16 and bonded together to form an integrated unit. Has been converted.

Examples of the substrates 13, 14, 15 and 16 include non-magnetic substrates such as ceramics or crystallized glass, and magnetic substrates such as magnetic ferrite. In this experimental example, a magnetic substrate made of magnetic ferrite was used.

The metal magnetic films 11 and 12 are laminated metal films in which thin magnetic metal thin films are laminated via an insulating film for the purpose of improving high frequency characteristics.

As a material for forming the magnetic metal thin film, a material having excellent heat resistance capable of coping with glass bonding in the manufacturing process is preferable, and sendust (Fe-Al-Si) or Fe-Ru-Ga-Si, or Examples thereof include a crystalline magnetic metal material in which O, N, etc. are added, or a Fe-based or Co-based microcrystalline magnetic metal material. In addition, the thickness of the magnetic metal thin film is 2 to 1 layer for improving high frequency characteristics.
It is desirable that the thickness is 5 μm.

As one insulating film, for example, Si
An oxide film such as O ₂ or Ta ₂ O ₅ or a nitride film such as Si ₃ N ₄ is used. The thickness of the insulating film is preferably about 0.1 to 0.3 μm, for example.

In this experimental example, a general sendust film was used as the magnetic metal thin film, and a SiO ₂ film was used as the insulating film. And 3μ of magnetic metal thin film per layer
m, the insulating film was 0.2 μm, and five layers were laminated to form metal magnetic films 11 and 12.

In the magnetic head of the present experimental example, in order to regulate the track width Tw of the magnetic gap g (Tw is 13 μm in the present experimental example), the first abutting surface of the magnetic core halves 17 and 18 is first. Track width regulating grooves 20a, 20b, 21a, 2 which are formed by cutting out the substrates 13, 14 and the second substrates 15, 16 and the magnetic metal films 11, 12.
1b is provided, and the fused glass 19 is also filled in the groove formed by these. That is, the metal magnetic film 1
In the vicinity of the magnetic gap g, portions 1 and 12 are notched by the track width regulating grooves 20a, 20b, 21a and 21b, so that the thickness in the film thickness direction is the track width Tw.
Is the same as.

Further, winding grooves 22, 23 for coil winding and glass grooves 24, 25 are provided on the abutting surfaces of the magnetic core halves 17, 18, respectively.
In order to secure the bonding strength of 18, the fused glass 19 is also melt-filled between them. Further, in this magnetic head, step portions 26a and 26b are provided on both sides of the medium sliding surface that is in sliding contact with the medium, the contact width H against the medium is regulated, and the magnetic head is wound around the winding grooves 22 and 23. This winding groove 2 is used to improve the winding condition of the coil.
Winding auxiliary grooves 27, 28 are formed at positions facing the Nos. 2, 23, respectively.

That is, in the magnetic head of this experimental example, since the metal magnetic films 11 and 12 are obliquely connected to each other at a predetermined angle θ ₁ with respect to the medium sliding direction shown by an arrow M in the figure, Medium sliding surfaces 17a, 18 of the magnetic core halves 17, 18
The ratio of the metal magnetic films 11 and 12 in the medium sliding portion of a is relatively small, and the wear resistance is improved.

Next, a method of manufacturing the above-described magnetic head shown in FIGS. 4 and 5 will be described in the order of steps. First, as shown in FIG. 6, a substrate 31 made of magnetic ferrite is prepared, and both surfaces of the substrate 31 are mirror-finished by polishing or the like. Next, as shown in FIG. 7, a metal magnetic film 32 is deposited on one surface of the substrate 31 by sputtering or the like.

When the metal magnetic film 32 is formed, a base film may be formed in advance on the substrate 31 in order to improve the adhesive force with the substrate 31, and the base film is SiO ₂ , An oxide film such as Ta ₂ O ₅ , a nitride film such as Si ₃ N ₄ , a metal film such as Cr, Al, Si and Pt and an alloy film thereof, or a laminated film combining them. It In this experimental example, a SiO ₂ film having a film thickness of 50 nm was used.

The metal magnetic film 32 is formed by stacking a number of magnetic metal thin films made of sendust having a small thickness with an insulating film made of SiO ₂ interposed therebetween in order to improve high frequency characteristics. When forming the magnetic head of this experimental example, five magnetic metal thin films each having a film thickness of 3 μm were stacked with an insulating film having a film thickness of 0.2 μm interposed therebetween.

The thickness of the metal magnetic film 32 is set to a desired track width of 1. because it is necessary to form a track width regulating groove for defining the film thickness of the metal magnetic film 32 in a later step. It is necessary to make the thickness about 2-3 times.

Further, the metal magnetic film 32 on the substrate 31
As shown in FIG. 8, low melting point glass films 33a and 33b are formed on the upper surface and the opposite surface thereof. At this time, a base film may be formed between the metal magnetic film 32 and the substrate 31 and the low melting point glass film 33 for the purpose of preventing the reaction between the metal magnetic film 32 and the substrate 31 and the low melting point glass films 33a and 33b. As the underlayer film, an oxide film such as SiO ₂ , Ta ₂ O ₅ or S
A nitride film of i ₃ N ₄ or the like, a metal film of Cr, Al, Pt or the like, an alloy film of these, or a laminated film combining them can be used. In this experimental example, a Cr film having a thickness of 0.1 μm was formed as a base film.

The low melting point glass films 33a and 33b are formed by sputtering low melting point glass,
Alternatively, the one formed by applying frit glass by spin coating or the like can be used.
0.1 μm to 0.5 μm is preferable. In this experimental example, the low-melting glass films 33a and 33b were formed by sputtering PbO-based low-melting glass having a thickness of 0.2 μm.

Although the low melting point glass films 33 are formed on both sides of the substrate 31 in this experimental example, the low melting point glass films 33 may be formed on only one side.

Then, the substrate 31 on which the metal magnetic film 32 and the low melting point glass film 33 are formed as described above is a substrate 31 as shown in FIG. 9 (hereinafter, the low melting point glass film 33 is not shown). A plurality of metal magnetic films 32 are laminated so as to be alternately arranged, and heated to 500 ° C. to 700 ° C. while applying pressure to bond the plurality of substrates 31 to each other.
4 is formed. At this time, the plurality of substrates 31 are stacked with an inclination angle indicated by α in the drawing. The inclination angle α is an angle calculated by the following formula 1.

Α = θ ₂ −θ ₁ (Equation 1)

Next, as shown in FIG. 10, both side surfaces which are stepped portions due to the lamination of the substrates 31 in the magnetic core block 34 are cut into surfaces having an inclination angle α, and these surfaces are cut into these surfaces. Install the magnetic core block 34 in two parallel cut surfaces.
The magnetic core half blocks 35 and 36 are formed by division.
Then, the divided cut surface is polished by using a surface grinder or the like to form winding grooves 37, 38 as shown in FIG. Then, at this cut surface, as shown in FIG.
The track width regulating grooves 39, 40 are formed by cutting or grinding so as to be orthogonal to the winding grooves 37, 38 at a position along the boundary line between the metal magnetic film 32 and the metal magnetic film 32. . At this time, the track width regulating grooves 39, 4
The width of the metal magnetic film 32 regulated by 0 is set to be the track width Tw, and is set to 13 μm in this experimental example.

The magnetic core half block 35,
After mirror-finishing the abutting surfaces of 36 by polishing or the like to form a gap film, as shown in FIG.
The magnetic core half blocks 35 and 36 are joined. At this time, the tracks of the magnetic core half blocks 35 and 36 are aligned, the metal magnetic films 32 are butted, and both magnetic core half blocks 35 and 36 are butted.
When the glass 41 having a lower melting point than the low melting point glass is fused, the glass 41 also flows into the track width regulating grooves 39 and 40, the magnetic core half blocks 35 and 36 are joined and integrated, and the abutting surfaces are formed. A magnetic head block 42 having a magnetic gap g therebetween is formed.

Next, after processing the winding auxiliary groove and cylindrical polishing of the medium sliding surface, as shown in FIG. 14, the magnetic particles integrated and joined together so that the magnetic gap g has an azimuth angle θ _2. The core half blocks 35, 36, that is, the magnetic head block 42 is tilted and cut at a position intersecting at a predetermined angle with the extending direction of the metal magnetic film indicated by the lines XX 'and YY' in the drawing. , The magnetic head having the metal magnetic film exposed on the cut surface is divided for each magnetic head. Then, the stepped portion that defines the contact width with the medium is processed to complete the magnetic head described above.

In this experimental example, the magnetic head block 42 was cut by the various cutting methods described in Experimental Example 1 to manufacture magnetic heads, and the head output of each magnetic head was measured.

First, a diamond grindstone containing diamond abrasive grains having an average particle diameter of 2 to 6 μm is used, and the grindstone is rotated at a speed of 2000 m / min or more and 5000 m / min or less to obtain a magnetic head which is an object to be cut. Block 4
Example 1 was a magnetic head in which the magnetic head block 42 was cut by sending 2 at a feed rate of 20 mm / min or more and 80 mm / min or less.

Then, a diamond grindstone containing diamond abrasive grains having an average particle diameter of 20 to 30 μm is used, and the magnetic head block 42 is cut in the same manner as in Example 1 with respect to the rotational speed of the grindstone and the feeding speed of the dummy substrate. After that, a magnetic head whose cut surface was polished as described in Experimental Example 1 was used as Comparative Example 1. In the polishing, as shown in FIG. 15, as a polishing jig 51, a processed surface 52a, which is a cut surface of a magnetic head 52 produced by cutting the magnetic head block 42, is formed on the adhesive surface 51a. A plurality of magnetic heads 52 are adhered to the adhering surface 51a by using an adhesive such as wax so as to face the above, and the apparatus as shown in FIG. 2 is used. The polishing was naturally performed on the cut surfaces on both sides of the magnetic head 52, and after the polishing, the magnetic head 52 was removed from the jig and washed.

Further, a diamond grindstone containing diamond abrasive grains having an average particle diameter of 20 to 30 μm was used, and the magnetic head block 42 was cut in the same manner as in Sample 1 at the rotational speed of the grindstone and the feed speed of the dummy substrate. A magnetic head was used as Comparative Example 2.

FIG. 16 shows the measurement results of the head output of Example 1 and Comparative Examples 1 and 2. The vertical axis in the figure indicates the relative output,
The horizontal axis represents frequency, and the solid line in the figure indicates Example 1 and Comparative Example 1
And the broken line in the figure shows the result of Comparative Example 2. In the frequency range of 0.6 MHz to 4 MHz, there is no difference in the results of Example 1 and Comparative Examples 1 and 2, and the solid line and the broken line overlap with each other.

From the results of FIG. 16, it is understood that the results of Example 1 and Comparative Example 1 are equivalent, and Comparative Example 2 is inferior to them in the high frequency region.

In Comparative Example 1, as described in Experimental Example 1, after cutting the magnetic head block, the cut surface was polished to remove the damaged portion of the insulating layer in the metal magnetic film on the cut surface. However, the magnetic insulation is ensured and the magnetic permeability of the metal magnetic film is made good, so that the head output is high and a good head output can be obtained even in the high frequency region as shown in FIG.

On the other hand, in Example 1, as described in Experimental Example 1, the magnetic head block was cut using a diamond grindstone using diamond abrasive grains having an average grain size of 2 to 6 μm. Therefore, the insulating layer in the metal magnetic film of the cut surface is less likely to be damaged, magnetic insulation is secured, and the grindstone is 2,000 m / min or more, 500 m / min or more.
The magnetic head block, which is the object to be cut, is rotated at a speed of 0 m / min or less and 20 mm / min or more, 80 mm / min.
Since the feed speed is less than min, the insulating layer in the metal magnetic film on the cut surface is less likely to be damaged, the magnetic permeability of the metal magnetic film is good, and the head output is high even in the high frequency range. It was confirmed that a high head output comparable to that of Comparative Example 1 was obtained.

On the other hand, in Comparative Example 3, as described in Experimental Example 1, since the cut surface has a rough surface, the insulating layer in the metal magnetic film on the cut surface is damaged, It has been confirmed that the magnetic permeability of the metal magnetic film is also significantly reduced, which results in a low head output.

A similar experiment was carried out using cubic boron nitride abrasive grains instead of diamond abrasive grains as the abrasive grains used in the grindstone, but the same results as in the above experimental example were obtained.

Next, Example 1 and Comparative Example 1 as described above
5, the distance from the magnetic head mounting surface 53a of the drum 53 to the edge of the magnetic gap g of the magnetic head when it is mounted on the drum 53 of the VTR as shown in FIG. The variation in height was investigated. Results are shown in FIG. FIG. 17
The vertical axis indicates the relative deviation from the track height reference value in each magnetic head, Δ in the figure shows the result when Comparative Example 1 was used, and × shows the result when Example 1 was used. Show.

As can be seen from the results shown in FIG. 17, the difference R between the maximum track height and the minimum track height indicating the variation in track height when the magnetic head of Comparative Example 1 is used.
Is R = 10 μm, whereas the variation in track height when the magnetic head of Example 1 is used is greatly improved to R = 3 μm. From these results, in the magnetic head of Comparative Example 1, the cutting surface is polished as described above, and the track height of the magnetic head itself varies. It can be seen that the variation becomes large because it depends on two factors, that is, the variation in the track height and the variation in the height of the magnetic head mounting surface of the drum. On the other hand, in the magnetic head of Example 1, since the cut surface is not processed after cutting, there is no variation in the track height of the magnetic head itself, and the track height is the height of the magnetic head mounting surface of the drum. It can be seen that the variation is suppressed only to a small extent, and the variation is suppressed to be small. Further, when the variation in track height is small as in Example 1, the above-mentioned pair yield is also high and is almost 100%. In Comparative Example 1, it was about 70%.

From the results of Experimental Examples 1 and 2, the magnetic core half block, which was joined and integrated so that the end faces of the metal magnetic films were butted against each other as in the method of manufacturing the magnetic head of this embodiment, was extended to the metal magnetic film. When cutting so as to intersect with the existing direction at a predetermined angle, if a grindstone using abrasive grains with an average grain size of 2 μm or more and 6 μm or less is used, the insulating layer in the metal magnetic film of the cut surface is damaged. Hard to occur, magnetic insulation is secured,
Furthermore, if the rotational speed of the grindstone is 2000 m / min or more and 5000 m / min or less, and the feed speed of the magnetic core half block integrally joined is 20 mm / min or more and 80 mm / min or less, It was confirmed that breakage of the insulating layer in the metal magnetic film is less likely to occur, the magnetic permeability of the metal magnetic film is good, and a magnetic head having a good head output is manufactured.

Further, in the method of manufacturing a magnetic head of the present invention, since the cut surface of the magnetic head is not subjected to polishing processing such as polishing, variations in the track height of the manufactured magnetic head are unlikely to occur, and the dimensions are reduced. It is possible to form a magnetic head with stable accuracy, improve the manufacturing yield,
Productivity is also improved. Therefore, the pair yield can be increased when the magnetic head is mounted on the VTR.

Further, in the method of manufacturing the magnetic head of the present invention, since the cutting surface of the magnetic head is not polished, complicated work is eliminated, the manufacturing process is shortened, and the magnetic head is attached to the polishing apparatus. Removal is not necessary, damage to the magnetic head is less likely to occur, manufacturing yield is improved, and productivity is improved.

[0070]

As is apparent from the above description, according to the present invention, a pair of magnetic core halves, in which a metal magnetic film is sandwiched by a pair of substrates in the thickness direction, are provided on the end faces of each metal magnetic film. After they are joined and integrated by butting each other, the joined and joined magnetic core halves are cut at a position where they intersect at a predetermined angle with respect to the extending direction of the metal magnetic film, and the metal is cut on the cut surface. In a method of manufacturing a magnetic head for forming a magnetic head having a magnetic film exposed, cutting of the magnetic core halves integrally bonded and joined has an average particle size of 2 μm or more, 6
Since it is performed using a grindstone using abrasive grains of μm or less, the insulating layer in the metal magnetic film on the cut surface is less likely to be damaged, magnetic insulation is secured, and the magnetic permeability of the metal magnetic film is improved. A magnetic head having a good head output is manufactured.

Further, in the present invention, the rotational speed of the grindstone at the time of cutting the magnetic core half body integrated and joined is 2000 m.
/ Min or more and 5000 m / min or less and the feed speed of the magnetic core half body integrally joined is set to 20 mm / min or more and 80 mm / min or less, further damage to the insulating layer in the metal magnetic film on the cut surface is caused. It is less likely to occur, the magnetic permeability of the metal magnetic film is good, and a magnetic head having a good head output is manufactured.

Further, in the method of manufacturing a magnetic head of the present invention, since the cut surface of the magnetic head is not subjected to polishing or the like, variations in the track height of the magnetic head hardly occur, and the magnetic head with stable dimensional accuracy. Can be formed, the manufacturing yield is improved, and the productivity is also improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing a dummy substrate used in Experimental Example 1.

FIG. 2 is a schematic perspective view of a main part schematically showing a polishing apparatus.

FIG. 3 is a diagram showing a relationship between frequency and magnetic permeability of a metal magnetic film.

FIG. 4 is a perspective view showing a magnetic head manufactured in Experimental Example 2.

FIG. 5 is a plan view showing a magnetic head manufactured in Experimental Example 2.

FIG. 6 is a perspective view showing a method of manufacturing a magnetic head in Experimental Example 2 in the order of steps, showing steps of mirror-finishing a substrate.

FIG. 7 is a perspective view showing a step of forming a metal magnetic film on a substrate.

FIG. 8 is a perspective view showing a step of forming a low melting point glass film.

FIG. 9 is a perspective view showing a step of forming a magnetic core block.

FIG. 10 is a perspective view showing a process of forming a magnetic core half block.

FIG. 11 is a perspective view showing a step of forming a winding groove in the magnetic core half block.

FIG. 12 is a perspective view showing a step of forming a track width regulating groove in a magnetic core half block.

FIG. 13 is a perspective view showing a step of joining magnetic core half blocks.

FIG. 14 is a plan view showing a step of cutting a magnetic head block.

FIG. 15 is a perspective view showing an example of a polishing jig.

FIG. 16 is a diagram showing a relationship between frequency and relative output of the magnetic head.

FIG. 17 is a diagram showing variations in track height between Example 1 and Comparative Example 1.

[Explanation of symbols]

 11, 12, 32 ... Metal magnetic film 13, 14, 15, 16, 31 ... Substrate 17, 18 ... Magnetic core half body 35, 36 Magnetic core half body block g ... Magnetic gap

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsushi Sato 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation

Claims (4)

[Claims] 1. A pair of magnetic core halves in which a metal magnetic film is sandwiched by a pair of substrates in the film thickness direction are joined and integrated so that the end faces of the metal magnetic films are abutted to each other. A magnetic head that forms a magnetic head in which a magnetic core half body that has been joined and integrated is cut at a position that intersects the extending direction of the metal magnetic film at a predetermined angle to expose the metal magnetic film on the cut surface. In the manufacturing method of, the average particle diameter of the magnetic core halves integrally bonded is 2
A method of manufacturing a magnetic head, which is carried out by using a grindstone using abrasive grains having a size of not less than μm and not more than 6 μm. 2. The rotational speed of the grindstone at the time of cutting the magnetic core halves integrally joined together is 2000 m / min or more, 500 or more.
The feed rate of the magnetic core half body joined and integrated is 20 mm / min or more, 80 mm / min or less at 0 m / min or less.
The method of manufacturing a magnetic head according to claim 1, wherein: 3. The method of manufacturing a magnetic head according to claim 1, wherein the abrasive grains used for the grindstone are diamond abrasive grains. 4. The abrasive grain used for the grindstone is cubic boron nitride abrasive grain.
A method for manufacturing the magnetic head described.