JPH05174321A - Production of magnetic head - Google Patents

Abstract

PURPOSE:To lessen the generation of the cracking of chips in production stages by using glass of <=0.1mg/cm<2> loss on weight when immersed for one hour in pure water kept at 100 deg.C as sealing glass. CONSTITUTION:A rod of a proper size is obtd. by material layout (a) from a ferrite ingot and outside shape grinding (b). The rod is then grooved for sealing glass by tracking (c) and the sealing glass is molded (d) into this groove. The excess glass is ground and a gap surface is polished (e) after working a winding groove. A gap material, such as quartz, is then sputtered and the gap surfaces are sealed to form a gap (f). The rod is cut (g) to chips and the flanks are polished (h) to a proper size. The chip is adhered to a base (i) and the tape traveling surface is polished (j) and winding (k) is applied to complete the head. The glass of <=0.1mg/cm<2> loss on weight when immersed for one hour in pure water kept at 100>= is used as the sealing glass of this time. The sealing strength of the head is thereby increased and the cracking of the chip at the time of cutting the rod to the chips is obviated in the production stages.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art In recent years, with the development of electronics, the demand for various glass products has increased, and various ideas have been made for the sealing glass for magnetic heads.

FIG. 1 shows a typical manufacturing process of a magnetic head used in a VTR. Material removal (a) is performed from a ferrite ingot, and this is formed into a rod having an appropriate size by external grinding (b). Next, a groove for sealing glass is made by the track processing (c), and the sealing glass is molded (d) in this groove. Then grind the extra glass,
After processing the winding groove, the gap surface is polished (e). Next, after sputtering a gap material (such as quartz), sealing and gap formation (f) are performed. Next, this is cut into chips (g) and then side-polished (h) to obtain an appropriate size. Next, the chip is bonded to the base (i), the tape running surface is polished (j), and the winding (k) is completed to complete the head.

Ferrite has been most widely used as such a VTR head, but since it has a low saturation magnetic flux density, the magnetic saturation of the head becomes a problem when it is used for a high density recording medium such as a metal tape which has recently appeared. I can not cope. Therefore, a magnetic alloy having a high magnetic permeability and a high saturation magnetic flux density, that is, an amorphous alloy or a superstructure nitriding alloy has been invented as a magnetic material to replace ferrite, and is used for broadcasting stations and S-VHS.
Has been put to practical use in a VTR called. The head using this magnetic material has a step of sputtering the magnetic material between the steps (b) and (c) of FIG.

Amorphous alloys and superstructure nitriding alloys easily change their magnetic properties due to heat, and the working temperature of the sealing glass used for head assembly is 500 ° C. or lower or 600 ° C., respectively.
It was necessary to keep the temperature below ℃, so low-melting glass with extremely high PbO content was used.

[0006]

However, such a glass has a working temperature of, for example, 600 for sealing a core made of a ferrite bulk material which has been widely used conventionally.
It was inferior in water resistance and strength as compared with glass having a relatively high melting point of about 800 ° C. For this reason, the head has a weak sealing strength, and there are many problems that the chip is broken when it is cut into chips in the manufacturing process.

[0007]

In order to solve the above problems, the present invention uses, as a sealing glass, a glass whose weight loss when immersed in pure water at 100 ° C. for 1 hour is 0.1 mg / cm ² or less. It is characterized by that.

[0008]

According to the manufacturing method of the present invention, the sealing strength of the head is increased, so that the chip does not break when it is cut into chips in the manufacturing process.

[0009]

EXAMPLES The present invention will be described with reference to Table 1 and FIG. Nos. 1 to 5 in (Table 1) show the weight loss and composition of the glass having various water resistances used in this example when immersed in pure water at 100 ° C. for 1 hour. Also in FIG.
This is an examination of the chip breakage rate and the strength of the remaining chips in the chip cutting process when the head was manufactured according to the process of FIG. 1 using the No. 1 to 5 glass.

[0010]

[Table 1]

As is clear from FIG. 2, the chip cracking rate increases as the weight loss increases, that is, the water resistance decreases, and reaches 90% when the weight loss reaches 14 mg / cm ² . Along with this, the chip strength dropped to an average of 6 g. This is caused by the large amount of water contained in the polishing liquid in the gap surface polishing step in Fig. 1 (e), which causes the glass on the surface to deteriorate, and in the gap forming step in (f) both cores are firmly sealed by the glass. It is presumed that it was not done. But the weight loss is 0.1m
Chip breakage rate is 0% when glass below g / cm ² is used
Moreover, the average chip strength was 58 g.

As described above, the weight loss of the sealing glass is 0.1 m.
It was confirmed that a magnetic head with excellent chip sealing strength can be realized by using glass of g / cm ² or less.

The composition of the glass used in the examples is shown as an example of the composition of the glass for each weight loss, and is not limited to the above-mentioned composition, and other compositions can be used as long as the weight loss conditions are satisfied. It is also possible to have a composition,
In addition to the glass containing PbO as the main component, V ₂ O ₅ system and TeO
It is also possible to use a low melting point glass such as a ₂ type or P ₂ O ₅ type. Further, the magnetic material is not limited to the amorphous alloy or the superstructure nitride alloy, and a sendust alloy can be used.

[0014]

As described above, according to the present invention, chip cracks that occur during the magnetic head manufacturing process can be reduced.

[Brief description of drawings]

FIG. 1 is a typical manufacturing process diagram of a magnetic head.

FIG. 2 is a diagram showing the relationship between the chip cracking rate and the strength of the remaining chips in the chip cutting process in the example of the present invention.

Claims (1)

[Claims] 1. A magnetic head formed by sealing a pair of core halves, each having a magnetic body made of a magnetic alloy having a high magnetic permeability and a high saturation magnetic flux density formed on a substrate, by sealing glass. A method of manufacturing a magnetic head, characterized in that a glass having a weight loss of 0.1 mg / cm ² or less when immersed in pure water at 100 ° C. for 1 hour is used.