JPS6238515A - Production of 'sendust(r)' alloy magnetic head core - Google Patents

Abstract

PURPOSE:To find gap defects in the early stage by subjecting a front part to head grooving after the width of a front surface is set and dividing a junction block in the direction crossing a linear groove by cutting after a reinforcing material is filled in the head groove. CONSTITUTION:A linear groove 3 is formed on the surface of one block plate 2a to divide this surface to a front part 4 and a back part 5. The front part 4 is subjected to non-adhesion work 4a like silica vapor-deposition, and faces to be laminated and joined of both block plates 2a and 2b are subjected to adhesion work 5a and 5b of a silver solder or the like. Both block plates 2a and 2b are allowed to face each other, and the silver solder on joint surfaces is fused with about 1kg/mm<2> pressure and about 1,000 deg.C temperature to join both block plates, and front side faces of both laminated blocks are ground along the linear groove to adjust the width of the front face to 0.03-0.6mm. After the front part is subjected to heat grooving in the direction orthogonal to the linear groove so that a track width T is left, a reinforcing material 13 is filled in a head groove 12.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for manufacturing a magnetic head core used in the recording/reproducing section of a high-density magnetic recording device such as a VTR, and more specifically, the present invention relates to a method for manufacturing a magnetic head core using a centast alloy as a material. This invention relates to a method of manufacturing a magnetic head core that can detect at an early stage the presence of foreign matter in the gap that greatly affects the mechanical part of the magnetic head, and as a result, reduces waste in the manufacturing process as much as possible. be.

[Prior Art] There is a strong demand for high reliability and high density in magnetic heads used in fields such as VTRs and audio recording, and magnetic head materials are shifting from permalloy and ferrite to centast alloys. In addition, magnetic head cores with narrow gap widths and narrow track widths are becoming available. Metallic magnetic materials, represented by Centast alloys, have the property of having a higher saturation magnetic flux density than conventional ferrite-based materials, and are attracting attention for this reason. There are some aspects that cannot be applied to the manufacture of centast alloy heads, and for this reason, new methods have been developed for using silver solder, for example, for blowing and cutting plates.

FIG. 4 is an explanatory diagram showing the conventional manufacturing procedure of a magnetic head core made of a Centast alloy (hereinafter simply referred to as Centast). of! /J out.

Next, in step (B) (generally referred to as wafer processing), the block plate is divided into a block plate 2a for groove processing and a block plate 2b for non-groove processing, and a straight groove is formed on the plate surface (especially one side surface) of the former 2a. form 3. The straight groove 3 is a coil winding window W which will be described later.
[See FIG. 4(H)], and is generally formed near one side of the groove processing block plate 2a and parallel to the side edge S.

The narrower bank with the straight groove 3 in between is called the front part 4, and the wider bank is called the back part 5. And (C
) process, the surface of the front part 4 is subjected to non-adhesive processing (a process of depositing a non-magnetic substance in the form of a Q film, also referred to as non-magnetic film deposition process) 4a, and a block for non-groove processing is applied. On the surface of the plate 2b facing the front part 4a (see FIG. 4(E)), a comb blade 6 with a narrow track width T is formed by cutting in a direction perpendicular to the straight groove 3. In step CD), the comb blades 7 are formed on the front part so that the track widths T mentioned above are completely matched.

Next, in step (E), two block plates 2a are formed.

2b are stacked so as to face each other, and both are joined. When joining, silver solder or the like is interposed between the surface of the back part 5 and the surface of the block 2b facing it, but the front part 4 is treated with non-adhesive processing (for example, silica) as described above. (formation of a vapor deposited film), only the back part 5 is joined, and the front part 4 is simply in opposing contact. However, this opposing abutment is required to be extremely accurate considering the narrow track width T. However, this track width T is generally 2
Since it is extremely thin with a thickness of approximately 0 to 30 gm, it is difficult to avoid the occurrence of burrs no matter how much precision cutting machine you use (reference photo), which is a serious obstacle to improving the gap accuracy of the opposing island contact surface. ing. Also, both block plates 2a
, 2b must be avoided at all costs when stacking and bonding (particularly in the track width direction); however, due to insufficient work jigs to guarantee positioning accuracy, misalignment often occurs and the magnetic head This causes a decrease in the regenerative power of the product.

The magnetic head core is then filled with reinforcing material 8 in the step (F), and cut and divided in the step (G) [the cutting line is shown by a broken line in the step (F), and the angle α is called the azimuth angle. ] It is manufactured through polishing of the front part in the (H) process, but there are burrs that occur during the comb cutting process in the (C) and (1)) processes, as well as misalignment that occurs in the (E) process. In the end, the poor accuracy based on this will be carried over to the end.

[Problems to be solved by the invention] Non-inventors etc. should ignore this IS situation! Taking this into consideration, we have repeatedly conducted tests 3-i to solve the above-mentioned misalignment defects, and have previously proposed a method of manufacturing a magnetic head core as shown in FIG.

That is, the above method is a modification of the conventional technique in which the surfaces on which burrs have been generated by comb shaving are made to come into contact with each other after 31F, and by performing comb shaving on the front parts that have been brought into facing contact in advance, the burrs are removed. This prevents deterioration of gap accuracy. That is, as shown in FIG. 3, the front part 4 of the block plate 2a, which has a straight groove 3 cut out from a rectangular block, has a continuous groove that is approximately parallel to the straight line 1+1!3 and cuts out the side edge corners of the block plate. After forming the notch step 9, the block 2a and block 2b with the notch step 9 formed therein.
are laminated and bonded, and a low melting point brazing material 11 is filled and bonded into the cavity 10 surrounded by the facing side edge corners of the notch block 2a and the other block plate 2b, and then the notch step is formed in the front part of the bonded block plate. A head groove is machined in the direction transverse to the track width T, and after filling the thus formed head t+lI 12 with a reinforcing material 13, the joint block is cut and divided as described above, and the groove is cut by polishing. When the joint made of the melting point brazing material is removed, a magnetic head core as shown in FIG. 3 (CG) is obtained. With the completion of the above method,
It was possible to eliminate poor gap accuracy due to curvature during comb machining and positional deviations when the comb machining parts were butted together.

However, this method requires a new process of filling and bonding the notch with a low melting point brazing filler metal in order to prevent track tearing and track misalignment during head groove machining, which only increases the number of manufacturing steps. However, the front gap width inspection, which is essential in the manufacturing process of magnetic head cores, cannot be performed until the low melting point brazing material is polished away after cutting and dividing, and cannot be performed until after the final process. A problem arises in that gap defects are not confirmed.

The present invention has been made in view of these circumstances, and it is an object of the present invention to provide a method for manufacturing a magnetic head core that allows early detection of gap defects while streamlining the manufacturing process.

[Means for Solving the Problems] The method of the present invention that achieves the first object is that when manufacturing a magnetic head core using blocks manufactured by Centast, after laminating both blocks, the four front sides are formed with straight grooves. Polish in the direction along the front surface to a width of 0.03~
After making it 0.8 layer thick, we processed the head groove in the front part in a direction perpendicular to the straight groove direction and leaving the track width.
The gist is that after filling the formed head groove with reinforcing material, the joint block is cut and divided in a direction intersecting the straight groove.

[Function] In the method shown in Fig. 3, the reason why bonding using a low melting point brazing material was adopted was to prevent track tearing and track position shift when cutting the rad grooves, as described above. Ta. However, when the above-mentioned method is adopted, not only does the process become complicated as it becomes necessary to form a notch step for filling the low-melting point brazing bamboo material and filling the low-melting point brazing bamboo material, but also makes it difficult to inspect the gap at the front section. Since it is not possible to polish and cut out the part filled with the melting point brazing bamboo material, it takes too many man-hours to find a defective product, and therefore a large amount of man-hours is wasted as the defective product is discarded.

As described above, reinforcing with low melting point brazed bamboo material is an effective means for preventing tracks from tearing off, etc., but it is also a method that has many problems. Therefore, the inventors of the present invention have conducted various studies in order to provide a means to avoid track tearing, etc. without reinforcing the head groove with low-melting wax bamboo material, and as a result, they have arrived at the above structure.

In other words, the cause of track tearing is that the head is weak during machining, and that is why the above-mentioned reinforcing means were devised.1 The inventors believe that by devising the shape of the comb-like track, the above-mentioned problem can be solved. I thought that it might be possible to solve the problem, and I considered various things. In other words, the tooth-like track of the comb has a shape whose width is considerably smaller than its length (which corresponds to the total thickness of two blocks) and depth, and its strength in the width direction is small, so the force in the width direction is reduced during head processing. If this is applied, the tracks tend to bend or distort in the width direction, causing track misalignment, and are also likely to be torn off by cutting tools for head processing. Therefore, if the main objective is to improve the strength in the width direction, the track width However, as the track width increases, the performance of the magnetic head deteriorates, so in practice it is not possible to increase the track width that much. The length has little effect on the strength of the track, and increasing the length will not lead to an increase in strength.On the other hand, the depth of the comb's concave track will affect the final product shape [see Figure 3 (G)] It is sufficient to secure only the length necessary for this, and it is thought that in the past, the above depth was designed to be larger than necessary. That is, the depth of the tooth-like tracks of the comb is 0.03-0.
By making the width of the comb-tooth track shorter than the conventional one, the strength in the width direction of the comb-like track can be made sufficiently large, and as a result, the head groove can be processed without reinforcement. If the above depth is 0.033 layers, it will not be possible to secure the track length and depth required for magnetic head products.On the other hand, if the depth exceeds 0.8 layers, the track length and depth required for magnetic head products will not be secured. The strength in the width direction decreases, causing bending of the track during head groove machining, and in severe cases, the track may be torn off.

In manufacturing the magnetic head core according to the present invention, after the two blocks are laminated, the width of the front surface is set to <0.03 to 0.8 mm by grinding the four front surfaces in the direction along the straight groove. Then, the front part is machined with a head groove in a direction perpendicular to the straight groove direction, and then the formed head groove is filled with a reinforcing material, and the joint block is further cut and divided in the direction perpendicular to the straight groove. In the above-mentioned processing, for example, a peripheral blade type precision cutting machine is used, and the cutting may be performed by feeding the borazon magnet at a speed of about 0.4 mta/sec.

[Example] The manufacturing process of the method of the present invention will be explained with reference to FIG. (A
) In the step (B), a straight groove 3 is formed in the plate surface of one side 2a of the block plate cut out from the rectangular block of Centast, dividing it into a front part 4 and a back part 5.Next, in the step (B), the front part 4 is coated with silica vapor deposition, etc. In addition to applying a non-adhesive process 4a, adhesion processes 5a and 5b such as silver solder are applied to the laminated joint surfaces of both block plates 2a and 2b (the surface of the pack part 5 and the block plate 2b facing this).
Either one of b may be omitted.6 Next, in the step (C), both block plates 2a and 2b are faced and 1, for example, IKg/
A pressure of about m2 and a temperature of about 1000"C are applied to melt the silver solder on the joint surfaces and join them together. In the (D) process, the four front sides of both stacked blocks are cut in the direction along the straight groove. Polish the width of the front surface to 0.03 to 0.6.
Prepare to H. At this time, the four front surfaces may be prepared in the final curved shape as shown in (D a). In the 0th order (E) step, the front part is adjusted in a direction perpendicular to the straight groove direction and with a track width. After processing the head groove so as to leave a T, the head groove 12 is filled with reinforcing material 13 as shown in step (F). The type of reinforcing material 13 is not particularly limited, but it is desirable that it exhibits the same thermal behavior as the base material Centast, and has a coefficient of thermal expansion of (ioo~200)xlO-
'/'O materials are recommended, such as low melting point silver solder, glass.

Barium titanate, manganese oxide-nucleated nickel type (N
2 Cl type) ceramics, etc.

There is no particular restriction on the shape of the track groove 12, but it is most convenient to use a U-groove shape as shown. (6 to 10) degrees] When the joint block is cut and divided (
G) The core shown in the figure is obtained, and the individual front edges are polished to give a specific curved shape. (H) The magnetic head core shown in the figure is obtained. In addition, if the curved surface processing is performed in advance in step (D) as shown in FIG. (Da), the final curved surface processing can be omitted.

Example 1 When manufacturing a magnetic head core according to the method of the above example, the depth of the front part prepared in step (D) was variously changed.
As shown in the figure, the frequency of occurrence of troubles such as track tearing and track misalignment has changed. In other words, if the depth of the front section is less than 0.8 lIs, no trouble will occur at all, but if it exceeds 0.61, the frequency of trouble occurrence will increase as the value increases, and in particular, the rate of track tearing will increase. are doing.

Example 2 Seven magnetic cores were manufactured by the method shown in FIG. 4, the method shown in FIG. 3, and the method of the present invention, and the occurrence rate of track misalignment was investigated. It was done.

As shown in Table 1, the method of the present invention was able to obtain performance equivalent to or better than the method shown in FIG.

[Effects of the Invention] The present invention is configured as described above, and can obtain the effects summarized below.

(1) Without reinforcement with low melting point brazing material, the third
It is possible to obtain the same effect of preventing occurrence of misalignment as the method shown in the figure. In other words, operations such as filling a low melting point brazing material are not necessary, and the manufacturing process can be simplified.

(2) The radius of the gap in the front part is defined as ±lo% of only the thin film such as silica deposited on the front part, and is usually very small at 0.2 to 0.4 m. In general, about 40
% of defective products occur. In the method shown in Fig. 3, this gap defect inspection required a lot of time because the inspection was carried out after the four parts on the front side were polished as shown in Fig. 3 (H), but in the present invention. As shown in FIG. 1(D), since this is carried out at the stage of joining blocks before the head groove is machined, the inspection can be performed all at once, and the time required for inspection can be significantly reduced. Furthermore, since the defective products that have been generated have not undergone much processing, it is possible to reduce the number of man-hours wasted due to the disposal of the defective products.

[Brief explanation of drawings]

Fig. 1 is a perspective explanatory view showing the procedure of the method of the present invention, Fig. 2 is a graph showing the relationship between the depth of the front part and the trouble occurrence rate, Fig. 3 is a perspective explanatory view showing the procedure of the improved method, and Fig. 4 FIG. 2 is a perspective explanatory view showing a conventional manufacturing procedure.

Claims (1)

[Claims] A pair of block plates made of Centast alloy are used as raw materials, and a straight groove is formed on the surface of at least one of the block plates to make the bank on one side the front part and the bank on the other side the back part. A centast alloy magnetic head core comprising the steps of: laminating both block plates so as to sandwich the two block plates; bonding the back portion to the surface of the other block plate; and cutting and dividing the obtained bonded block in a direction intersecting the linear groove. In the manufacturing method, after both blocks are stacked, the front side surfaces are polished in the direction along the straight groove, and the width of the front surface is reduced to 0.
03 to 0.6 mm, a head groove is processed on the front part in a direction perpendicular to the straight groove direction and to leave the track width, and after filling the formed head groove with reinforcing material, the joining block is cut into a straight groove. A method of manufacturing a centast-based alloy magnetic head core characterized by cutting and dividing in a direction intersecting with the .