JPH0863706A - Production of magnetic head - Google Patents

Abstract

PURPOSE: To improve the utilization rate of materials by cutting and separating a magnetic core substrate at reference lines for cutting, thereby forming magnetic core blocks. CONSTITUTION: Thin films of gap spacers (not shown in Fig.) consisting of a nonmagnetic material, such as silica, are deposited on the groove 4 forming surfaces of at least one of the substrates 15 and thereafter, two sheets of the substrates 15, 15 are butted against each other and are heated. The heated substrates are joined and integrated by glass 7, by which the magnetic core substrate 16 is produced. Next, both side face parts 9, 9 parallel with the joint surface of the substrate 16 are then ground down to the thickness size of the finished magnetic core as shown by alternate long and short dash lines, by which the substrate 16 is separated in the parts of the reference grooves 14 for cutting by which the magnetic core blocks are obtd. These core blocks are sliced at the plane orthogonal with the joint surfaces in the central part of the track groove, by which the magnetic core chips are obtd. The bottom end faces of the resulted core chips are exactly worked to the prescribed size from a gap depth reference line and, therefore, the magnetic heads having the exact gap depth are mass produced when the magnetic heads are assembled with these bottom end faces as reference planes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head used in a magnetic recording apparatus, and more particularly to a method of manufacturing a magnetic head suitable for mass production with improved gap depth processing accuracy.

[0002]

2. Description of the Related Art Conventionally, in a method of manufacturing a so-called bulk type magnetic head using a ferromagnetic oxide material as a magnetic core, in order to accurately process the gap depth, the lower end of the magnetic core block is kept at a constant dimension from the gap depth reference line. A method of manufacturing a magnetic head, which is cut and the lower end surface of the magnetic core block is used as a reference surface of the gap depth, as disclosed in JP-A-2-179907 is generally adopted. A method of manufacturing this magnetic head will be described with reference to the drawings. As shown in FIG. 4, the winding groove 2 and the V-shaped gap depth regulating groove 3 are formed on one surface of the ferromagnetic oxide plate 1.
A plurality of grooves 4 which are integrated with each other are formed at a predetermined interval. Then, as shown in FIG. 5, on the surface on which the groove 4 is formed, track grooves 5 for restricting the track width of the magnetic gap are formed at predetermined intervals in the direction orthogonal to the groove 4 to manufacture the substrate 6. . Then, as shown in FIG. 6, a gap spacer (not shown) made of a non-magnetic material such as silica on the groove 4 forming surface of at least one of the two substrates 6.
After depositing the thin film of, the gap depth regulating groove 3 is abutted with the groove 4 forming surfaces with their end faces slightly displaced so that they can be easily observed, heated, and joined together by the glass 7 to form a magnetic field. The core substrate 8 is manufactured.

Then, in order to prevent deformation due to heat treatment or the like at the time of bonding, a material thicker than half the thickness of the completed magnetic core is usually used. Therefore, as shown in FIG. After the side surface portions 9 and 9 parallel to the joint surface are polished to the thickness dimension of the completed magnetic core as shown by the dashed line in the figure, the gap depth regulating groove 3 forms the gap depth. Observe the reference line 10 from the end face side that is slightly displaced and joined, and with a constant dimension L from the gap depth reference line 10, as shown by the dotted line in the drawing, parallel to the gap depth regulating groove 3 and orthogonal to the joining face. The surface is cut and separated to form the lower end surface of the magnetic core chip. Then, as shown in FIG. 8, the magnetic core block 11 obtained by separation is sliced at the central portion of the track groove 5 and at a surface orthogonal to the bonding surface as shown by a dotted line in the drawing,
A magnetic core chip 12 as shown in FIG. 9 is created.

By manufacturing the magnetic core chip 12 in the above-described process, the magnetic core chip 12 having the lower end surface 13 as a reference surface for the gap depth is obtained, and the lower end surface of this magnetic core chip 12 is obtained in the subsequent magnetic head assembly process. By processing using 13 as a reference surface, a magnetic head having an accurate gap depth is assembled.

[0005]

However, according to the above-described method of manufacturing a magnetic head, when the magnetic core substrate is cut and separated from the gap depth reference line with a certain size to form a magnetic core block, the substrates are joined together. Since the glass used for the above is rubbed on the side surface of the joint and it is difficult to observe the depth reference line, it is necessary to shift the end faces of the substrates to abut against each other, which causes a problem that the utilization factor of the material is reduced. Moreover, since a plurality of magnetic core blocks are created from the magnetic core substrate, it is necessary to observe the gap depth reference line and adjust the cutting dimension every time the cutting process is performed, which causes a problem of increasing the number of cutting processes. there were. Furthermore, since this cutting area is large and the amount of processing is large, the processing accuracy decreases due to wear and deformation of the thin rotary cutting blade used for cutting,
There is also a problem that the distance between the reference plane and the gap depth reference line becomes inaccurate.

Particularly, in manufacturing a composite magnetic head in which ferromagnetic metal thin films are arranged on both sides of a magnetic gap and a ferromagnetic oxide is used as a magnetic core, when the magnetic core substrate is separated and cut,
Since it is necessary to cut different materials of the ferromagnetic oxide and the ferromagnetic metal laminated on it, the cutting speed can be changed or a cutting blade suitable for each material can be used to form one groove. However, there is a problem in that it requires multiple processing. The present invention is proposed in order to solve the above-mentioned conventional problem, and facilitates the cutting and separating process of the magnetic core substrate by simultaneously forming the cut reference grooves at a constant size interval when forming the gap depth regulating groove. In addition, it is an object of the present invention to provide a method for manufacturing a magnetic head in which the processing accuracy of the dimension of the lower end surface of the magnetic core chip, which serves as the reference surface for the gap depth, is improved.

[0007]

In order to solve the above problems, in the present application, a step of forming a gap depth regulating groove and a cutting reference groove at a predetermined interval on one surface of a plate made of a ferromagnetic oxide; A step of forming a substrate by forming a track groove in a direction orthogonal to the gap depth regulating groove on the gap depth regulating groove forming surface of a plate made of an oxide;
Forming a magnetic core substrate by integrally joining the two substrates so that the track groove forming surfaces face each other, and in the cutting reference groove of the magnetic core substrate, the magnetic core substrate is joined in parallel with the cutting reference groove. Provided is a method of manufacturing a magnetic head, which comprises a step of forming a magnetic core block by separating the magnetic core block on a surface orthogonal to a surface and a step of slicing the magnetic core block parallel to a track groove to form a magnetic core chip. Further, in the above manufacturing method, the thickness of the plate made of the ferromagnetic oxide is set to a material having a thickness larger than half of the thickness of the completed magnetic head, and the depth of the cutting reference groove is set to the completed magnetic head. The magnetic core block may be formed to be deeper than the thickness of the head, and after the magnetic core substrate is formed, both side surfaces parallel to the bonding surface may be polished to expose the cutting reference groove, and the magnetic core block may be separated at this portion. desirable.

Further, after a ferromagnetic metal thin film is formed on the track groove forming surface of the substrate, the two substrates are joined and integrated to form a magnetic core substrate, and the ferromagnetic metal thin film is formed by sputtering FeTaN. It is desirable to use an alloy thin film.

[0009]

According to the above-described method of manufacturing a magnetic head, when the gap depth regulating groove is formed, the cutting reference grooves are simultaneously formed at a constant size interval, and the magnetic core substrate is cut and separated by the cutting reference groove to form the magnetic core block. At the time of creation, it is not necessary to observe the depth reference line, and it is not necessary to shift the end faces of the substrates to abut each other, and as a result, the material utilization rate can be improved. Moreover, it is not necessary to observe the gap depth reference line and adjust the cutting dimension every time the cutting process is performed, and the number of cutting processes can be reduced. Furthermore, since the cutting area is reduced and the machining amount is also reduced, wear of the thin rotary cutting blade used for cutting is reduced and the service life is extended, and the machining accuracy of the reference surface is improved, so that the accurate gap depth is provided. The magnetic head is assembled.

In particular, when manufacturing a composite magnetic head having ferromagnetic metal thin films on both sides of the magnetic gap, only the ferromagnetic oxide plate needs to be cut when the magnetic core substrate is separated and cut. Since there is no need to change the cutting speed or replace with a cutting blade suitable for each material, cutting separation is greatly facilitated. Further, by forming the depth of the cutting reference groove deeper than the thickness of the completed magnetic head and separating it by side surface polishing, the separation by the cutting process becomes unnecessary.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the magnetic head manufacturing method of the present invention will be described with reference to the drawings. In the figure, the same parts as those of the conventional example are designated by the same reference numerals and the description thereof will be omitted. As shown in FIG. 1, one side of the ferromagnetic oxide plate 1 has winding grooves 2 and V
The groove 4 having the V-shaped gap depth regulating groove 3 as one body, and the cutting reference groove 14 at a position of a predetermined dimension interval L from the gap depth reference line 10 are formed on the magnetic head where the depth of the cutting reference groove 14 is completed. A plurality of sets are formed at predetermined intervals so as to be deeper than half the thickness of the cord. Then, similarly to the conventional example, track grooves 5 for restricting the track width of the magnetic gap are formed at predetermined intervals on the surface on which the grooves 4 are formed, and the substrate 15 is manufactured. .

Then, as shown in FIG. 2, a thin film of a gap spacer (not shown) made of a non-magnetic material such as silica is deposited on at least one of the substrates 15 on which the groove 4 is formed. The substrates 15 and 15 of
The magnetic core substrate 16 is manufactured by joining and integrating with the glass 7. Next, both side surface portions 9 and 9 parallel to the bonding surface of the magnetic core substrate 16 are polished to have a thickness dimension of the completed magnetic core as shown by a dashed line in the figure, and the magnetic core substrate 16 is cut. The magnetic core block is obtained by being separated at the reference groove 14. Then, similarly to the conventional example, the magnetic core block is sliced at the center of the track groove and on the surface orthogonal to the bonding surface to prepare a magnetic core chip.

Since the lower end surface of the magnetic core chip thus obtained is accurately processed to a predetermined dimension from the gap depth reference line, if the magnetic head is assembled using this lower end surface as a reference surface. A large number of magnetic heads with accurate gap depth can be manufactured. Further, the method for producing a magnetic head of the present invention is applied to the production of a composite magnetic head in which ferromagnetic metal thin films are arranged on both sides of a magnetic gap and a plate made of a ferromagnetic oxide is used as a magnetic core. For example,
As shown in FIG. 3, the ferromagnetic metal thin film 17 formed on the ferromagnetic oxide plate 1 is formed only on the surfaces where the substrates 15 and 15 are butted and joined together. It suffices to polish only both side surface portions 9 of the ferromagnetic oxide plate 1. Therefore, there is no need to change the cutting speed or replace with a cutting blade suitable for each material.

The example in which the depth of the cutting reference groove 14 is formed as the substrate 15 deeper than half of the thickness of the completed magnetic head and is separated by polishing has been described, but the present invention is not limited to this. However, even when the thickness of the ferromagnetic oxide plate 1 is set to be equal to half the thickness of the completed magnetic head, the ferromagnetic oxide plate of the cutting reference groove 14 is separated when the magnetic core substrate 16 is separated. It suffices to cut only a part of 1, so that it is not necessary to change the cutting speed or replace it with a cutting blade suitable for each material. Also, the cutting reference groove 1
Since the formation surface of 4 forms a part of the lower end surface 13,
Since it can be used as a reference surface for assembling a magnetic head in a later step, a large number of magnetic heads having an accurate gap depth can be produced. Although the present embodiment has described the manufacturing method of cutting out three magnetic core blocks from one magnetic core substrate, the present invention is not limited to this, and one magnetic core block is cut out from one magnetic core substrate. Alternatively, it is also applied to a manufacturing method in which four or more magnetic core blocks are cut out from one magnetic core substrate.

[0015]

According to the present invention, when the gap depth regulating groove is formed, the cutting reference grooves are simultaneously formed at a constant size interval,
Since the magnetic core block is created by cutting and separating the magnetic core substrate with the cutting reference groove, it is not necessary to observe the gap depth reference line, and it is not necessary to shift the end faces of the substrate to abut against each other, improving the material utilization rate. it can. Moreover,
It is not necessary to observe the gap depth reference line every time the cutting process is performed and adjust the cutting dimension, and the number of cutting processes can be reduced. Further, since the cutting area is reduced and the processing amount is reduced, the thin rotary cutting blade used for cutting is also less worn and the life can be extended.

In particular, when manufacturing a composite magnetic head in which ferromagnetic metal thin films are arranged on both sides of the magnetic gap, only the ferromagnetic oxide plate needs to be cut when the magnetic core substrate is separated and cut. Since there is no need to change the cutting speed or replace with a cutting blade suitable for each material, cutting separation is greatly facilitated. Further, by forming the depth of the cutting reference groove deeper than the thickness of the completed magnetic head and separating by side surface polishing, it is possible to eliminate the need for separation by cutting.

[Brief description of drawings]

FIG. 1 is a perspective view of a main part of a substrate according to an embodiment of the present invention.

FIG. 2 is a perspective view of a main part of a magnetic core substrate according to an embodiment of the present invention.

FIG. 3 is a perspective view of a main part of a magnetic core substrate according to another embodiment of the present invention.

FIG. 4 is a perspective view of a main part showing formation of a conventional winding groove and depth end regulating groove.

FIG. 5 is a perspective view of a main part of a conventional substrate.

FIG. 6 is a perspective view of a main part of a conventional magnetic core substrate.

FIG. 7 is a perspective view of a main part showing a side surface polishing process of a conventional magnetic core substrate.

FIG. 8 is a perspective view of a main part of a magnetic core block.

FIG. 9 is a perspective view of a magnetic core chip.

[Explanation of symbols]

 1 Ferromagnetic Oxide Plate 3 Gap Depth Control Groove 4 Groove 5 Track Groove 7 Glass 9 Side Part 10 Gap Depth Reference Line 14 Cutting Reference Groove 15 Substrate 16, 18 Magnetic Core Substrate 17 Ferromagnetic Metal Thin Film L Gap Depth Reference Line and Cutting Distance from the reference groove

Claims (4)

[Claims] 1. A step of forming a gap depth regulating groove on one surface of a plate made of a ferromagnetic oxide at a predetermined distance from each other; a step of forming a cutting reference groove at a predetermined distance from the gap depth regulating groove; A step of forming a substrate by forming track grooves in a direction orthogonal to the gap depth regulating groove on the gap depth regulating groove forming surface of a plate made of a ferromagnetic oxide; and forming two substrates on the track groove forming surface. Forming a magnetic core substrate by facing and joining together to form a magnetic core substrate; and forming a magnetic core block separated by a cutting reference groove of the magnetic core substrate at a surface orthogonal to the joining surface of the magnetic core substrate, A step of slicing the magnetic core block parallel to the track groove to form a magnetic core chip. 2. The ferromagnetic oxide magnetic plate is made of a material having a thickness larger than half the thickness of the completed magnetic head, and the depth of the cutting reference groove is set to the depth of the completed magnetic head. 2. The magnetic core block according to claim 1, wherein the magnetic core block is formed to be deeper than the thickness of the magnetic core substrate, and after the magnetic core substrate is formed, both side surfaces parallel to the bonding surface are polished and separated by the cutting reference groove portion. Head manufacturing method. 3. The magnetic core substrate according to claim 1, wherein a ferromagnetic metal thin film is formed on the track groove forming surface of the substrate, and then the two substrates are joined and integrated to form a magnetic core substrate. Method of manufacturing a pad. 4. The method of manufacturing a magnetic head according to claim 3, wherein the ferromagnetic metal thin film is a FeTaN alloy thin film formed by sputtering.