JPH0981904A - Manufacturing method of magnetic head - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To significantly improve the processing efficiency required for processing the contact width of the magnetic head to improve the grinding processing efficiency, and to reduce the edge chipping that tends to occur on the sliding surface of the magnetic recording medium. Is 4 μm or less. SOLUTION: Using a resin bond grindstone, the grain size of the abrasive grains is # 3000 in consideration of the grinding precision and the grinding efficiency.
Alternatively, using a # 4000 resin bond grindstone, the grinding speed is 250 mm / min, and the peripheral speed is 5000 to 6
The predetermined width of 000 m / min is set, and the sliding surface of the magnetic recording medium is subjected to contact width processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention manufactures a magnetic head by abutting width processing on a sliding surface of a magnetic recording medium of a magnetic core block formed by a pair of magnetic core half blocks butted against each other through a gap material. Regarding the method.

[0002]

2. Description of the Related Art Usually, a video tape recorder (VTR) is used.
The magnetic head is provided on the peripheral surface of a rotating drum to form a rotary magnetic head device. When the sliding surface of the magnetic recording medium slides on a magnetic tape serving as a magnetic recording medium, images and sounds are provided. Recording / reproduction.

This magnetic head is provided with a magnetic core in which a pair of magnetic core halves made of a magnetic material such as ferrite are butted against each other via a gap film made of an insulating material such as SiO ₂ to form a magnetic gap. A wire material such as a copper wire is wound around the magnetic core to form a magnetic coil.

When manufacturing the above magnetic head, first, a plurality of strip-shaped track width regulating grooves are formed in one main surface of a pair of magnetic core half blocks at a gap width interval to form a predetermined shape described later by cutting or grinding. Then, a winding groove is further formed.

Next, the magnetic core half blocks are butted at the gap width intervals of the magnetic core half blocks on the one main surface. Here, a pair of magnetic core half blocks are joined by inserting a glass material for fusing into each opening formed by butting each track width regulation groove of each magnetic core half block and heating it to a high temperature. To produce a magnetic head block.

Subsequently, one main surface of the magnetic head block, in which the magnetic gap is formed, is cylindrically ground to form a sliding surface of the magnetic recording medium, and a guide groove for winding is formed. Contact width processing is performed on the sliding surface of the magnetic recording medium to secure a contact width with respect to the magnetic recording medium. in this case,
Normally, a resin bond grindstone in which each abrasive grain is bonded by a resin is used, and a resin bond grindstone with an abrasive grain size of # 2000 is used, and the grinding speed is 30 to 100 mm.
/ Min and the peripheral speed is 2000 to 3000 m / min, and the magnetic medium sliding surface is ground.

Then, the magnetic head block is subjected to a cutting process to manufacture each head chip having a magnetic gap. After that, the sliding surface of the magnetic recording medium of each head chip is subjected to contact width processing to produce the above magnetic core,
The magnetic head is completed by performing post-processing such as winding.

[0008]

By the way, when the sliding width of the magnetic recording medium of the magnetic core block is processed by the contact width grinding under the above-mentioned conditions using the resin bond grindstone, In some cases, the vicinity of the edge of the sliding surface of the recording medium is damaged and a chip (edge chip) with a maximum size of about 10 μm occurs.

In order to reduce the frequency of occurrence of the edge chipping or reduce the size thereof, it is sufficient to use a grindstone having a small grain size of abrasive grains, but this alone increases the wear on the grindstone and corrects the grindstone. The increase in the number of times and the deterioration of the grinding processing accuracy pose a problem. Further, in order to reduce the grinding efficiency, it is necessary to increase the grinding speed, but the higher the grinding speed, the more frequently the edge chipping occurs and its magnitude.

Recently, the demand for higher precision and higher efficiency of the magnetic head is increasing more and more, and it is necessary to perform the contact width processing at a relatively high grinding speed while maintaining high grinding accuracy. Is.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to significantly shorten the processing time required for processing the contact width of the magnetic head to improve the grinding processing efficiency. By suppressing the edge chipping that tends to occur on the sliding surface of the magnetic recording medium to 4 μm or less, damage to the magnetic recording medium caused by the edge chipping is prevented, and it is caused by the powder drop of the magnetic recording medium. It is an object of the present invention to provide a method of manufacturing a magnetic head that can reduce the clocks required for the production and can significantly improve the yield and reliability of products.

[0012]

The object of the present invention is to provide a magnetic recording medium on a sliding surface of a magnetic recording medium of a magnetic core block formed by a pair of magnetic core half blocks butted against each other via a gap film. This is a method of manufacturing a magnetic head by performing a contact width process for ensuring a contact width.

In the present invention, the abrasive grain size is # 300.
Using the grindstone of 0 to # 4000, the contact width processing is performed at a grinding processing speed of about 250 mm / minute and a peripheral speed of 5000 m / minute to 6000 m / minute.

In this case, specifically, a resin bond grindstone in which each abrasive grain is bonded by a resin is used as the grindstone.

Further, the present invention is suitable for application to a magnetic head in which a metal magnetic film made of a soft magnetic metal material is formed on each of the abutting surfaces of a pair of magnetic core half blocks constituting the magnetic core block. is there.

Here, the smaller the grain size of the abrasive grains, the higher the accuracy of the grinding process, but the grain size of the abrasive grains is # 30.
If it is smaller than 00, for example, # 2500, the size of the edge chipping generated on the sliding surface of the magnetic recording medium exceeds 4 μm, and the grain size of the abrasive grains is larger than # 4000, for example, # 4000.
When it is 5000, the magnetic core and the fused glass are cracked.

If the peripheral speed of the grindstone is less than 5000 m / min, the size of the edge chipping exceeds 4 μm, and if it exceeds 6000 m / min, the possibility of damage to the grindstone increases.

As described above, in the present invention, when the contact width processing is performed on the sliding surface of the magnetic recording medium of the magnetic core block, the grinding processing speed is set to a high value of approximately 250 mm / min and the grinding processing efficiency is set. In addition to improving the above, the grain size of the abrasive grains is set to the above-mentioned appropriate value, and the peripheral speed is set to a value within the above-mentioned appropriate range. It can be suppressed to a value of 4 μm or less. Therefore, the contact width processing is performed with high grinding processing accuracy while maintaining high grinding processing efficiency.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of a method of manufacturing a magnetic head according to the present invention will be described in detail below with reference to the drawings.

In the present embodiment, as a magnetic head to be manufactured, a plurality of strip-shaped track width regulating grooves are formed on one main surface with gap width intervals, and a metal magnetic film made of a soft magnetic metal material is formed. And a gap surface is formed to form a magnetic core half block, and the gap surfaces of the pair of magnetic core half blocks are butted against each other via a gap material to form a plurality of magnetic gaps to form a magnetic head block, The target is a so-called metal-in-gap type magnetic head (MIG head), which is obtained by cutting a head chip having a required chip width from this magnetic head block.

As shown in FIG. 1, the magnetic core 11 of this magnetic head has a metal magnet made of a soft magnetic metal material on each main surface of the pair of magnetic core halves 1 and 2 on which the track width regulating groove 3 is formed. A film 4 is formed, and the magnetic core halves 1 and 2 are abutted against each other on the main surfaces via a gap material to form a magnetic gap g. When these magnetic core halves 1 and 2 are butted against each other, a glass material for fusing is inserted into a glass groove (not shown) and melted at a high temperature to join the magnetic core halves 1 and 2.

Here, the magnetic core halves 1 and 2 are formed with a winding groove 5 and a guide groove 6 for winding a magnetic coil for passing a recording current. The winding groove 5 and the guide groove 6 are provided with windings (not shown) to form the MIG head.

In manufacturing the above magnetic head, first, a plurality of strip-shaped track width regulating grooves 3 are cut or ground at a gap width interval on one main surface of a pair of magnetic core half blocks to have a predetermined shape described later. Then, a winding groove (which will be the winding groove 5 later) is further formed.

Then, a metal magnetic film 4 made of a soft magnetic metal material such as sendust is formed on the one main surface of each magnetic core half block in which the track width regulating groove 3 is formed to have a thickness of several μm. The sputter film is formed uniformly over the entire surface. Thereafter, the magnetic core half blocks are butted at the gap width intervals of the magnetic core half blocks on the one main surface. Here, a pair of magnetic core half blocks are joined by inserting a glass material for fusing into each opening formed by butting each track width regulation groove 3 of each magnetic core half block and heating it to a high temperature. Then, a magnetic head block is manufactured.

Then, one main surface of the magnetic head block in which the magnetic gap is formed is subjected to cylindrical grinding to form a magnetic recording medium sliding surface (which will later become the magnetic recording medium a of each magnetic head). After making guide groove processing for winding,
Contact width processing is performed to secure the contact width against the sliding surface of the magnetic recording medium. In this case, a resin-bonded grindstone in which each abrasive grain is bonded by a resin is used, and the grain size of the abrasive grain is # 3000 in consideration of the grinding precision and the grinding efficiency.
~ # 4000 resin bond grindstone is used, grinding speed is 250 mm / min, and peripheral speed is 5000 to 60
The sliding surface of the magnetic recording medium is ground by setting each predetermined value within 00 m / min.

Here, the smaller the grain size of the abrasive grains, the higher the accuracy of the grinding process, but the grain size of the abrasive grains is # 30.
If it is smaller than 00, for example, # 2500, as shown in FIG. 2, the size of the edge chipping generated on the magnetic recording medium sliding surface a of the manufactured magnetic core 11 exceeds 4 μm, and the abrasive grains Particle size is greater than # 4000, eg # 50
In the case of 00, cracks occur in the magnetic core and the fused glass.

When the peripheral speed of the grindstone is less than 5000 m / min, the size of the edge chipping exceeds 4 μm, and when it exceeds 6000 m / min, the grindstone is likely to be damaged.

Then, this magnetic head block is subjected to a cutting process to manufacture each head chip having a magnetic gap. After that, the magnetic medium recording sliding surface of each head chip is subjected to contact width processing to manufacture the magnetic core 11,
The magnetic head is completed by performing post-processing such as winding.

As described above, in the present embodiment,
When performing the contact width processing on the sliding surface of the magnetic recording medium of the magnetic core block, the grinding processing speed is set to a high value of 250 mm / min to improve the grinding processing efficiency, and the grain size of the abrasive grains is set to the above appropriate value. Moreover, by setting the peripheral velocities to values within the above-mentioned appropriate ranges, even if an edge breakage occurs on the sliding surface of the magnetic recording medium, the size thereof can be suppressed to a value of 4 μm or less. Therefore, the contact width processing is performed with high grinding processing accuracy while maintaining high grinding processing efficiency.

[0030]

EXAMPLE In manufacturing the MIG head, when the sliding surface of the magnetic recording medium of the magnetic core block is subjected to width working, the grain size of the resin bond grindstone or the grinding speed is changed. An example will be described in which the size of the edge chipping that occurs on the sliding surface of the magnetic recording medium when the grinding process is performed is examined.

Example 1 First, as Example 1, similar resin bond grindstones A to E were used.
Is used as a sample and the grinding speed is 250 mm /
Min., The peripheral speed of the resin bond grindstone is set to 5000 m / min, the grinding depth is set to 0.1 mm, and the particle size of the abrasive grains of the resin bond grindstone is # 2500, # 3.
The maximum value of edge chipping that occurred on the sliding surface of the magnetic recording medium of the magnetic core block was measured for 000, # 4000, and # 5000. The measurement results are shown in Table 1 below.

[0032]

[Table 1]

As shown in Table 1, in the case of the grain size # 2500, the size of the edge chipping generated in all of the resin bond grindstones A to E exceeded 4 μm. On the other hand, in the case of grain sizes # 3000 and # 4000, the size of the edge chipping was 4 for all the resin bond grindstones A to E.
It was less than μm. Further, when comparing the sizes of edge chippings of the grain sizes # 3000 and # 4000 for the same resin bond grindstone, the grain size # 4000 is smaller. However,
Regarding the degree of wear of each resin bond grindstone, the grain size is # 4000.
In this case, the grain size is larger than that in the case of grain size # 3000, and the polishing precision is poor. For example, when the grain size of # 3000 and # 4000 is measured using the resin bond grindstone A, grooving of 2000 mm is performed on the single crystal ferrite plate, and the depth wear before and after grooving is measured.
In the case of a particle size of # 4000, the particle size was 28 μm. In the case of grain size # 5000, cracks occurred in the magnetic core blocks in all of the resin bond grindstones A to E.

Example 2 Subsequently, as Example 2, the above resin bond grindstones A to E were used.
Is used as a sample and the grinding speed is 250 mm /
Min., The grain size of the resin bond grindstone is set to # 4000, the grinding depth is 0.1 mm, and the peripheral speed of the resin bond grindstone is 4000 m / min.
The maximum value of the edge chipping that occurred on the sliding surface of the magnetic recording medium of the magnetic core block was measured at 00 m / min, 6000 m / min, and 7000 m / min. The measurement results are shown in Table 2 below.

[0035]

[Table 2]

As shown in Table 2, the peripheral speed is 4000 m
In the case of / min, there was a resin bond grindstone in which the maximum value exceeded 4 μm and caused edge chipping. Also, the peripheral speed is 70
In the case of 00 m / min, all the resin-bonded grindstones were broken during the grinding process, so it is understood that the limit value of the peripheral speed is between 6000 and 7000 m / min in consideration of the strength of the grindstone. Therefore, considering safety, it is realistic to set the limit value of the peripheral speed to 6000 m / min.
When the peripheral speed is 5000 m / min and 6000 m / min, the maximum value of edge chipping is 4 μm or less, and it is considered that the size of the edge chipping becomes smaller as it approaches 6000 m / min.

From the above results, the grain size of the abrasive grains is # 3000.
Alternatively, using a resin bond grindstone of # 4000, the grinding speed is 250 mm / min and the peripheral speed is 50.
By performing the above contact width processing at 00 m / min to 6000 m / min, it is possible to improve the grinding processing efficiency and suppress the edge chipping that tends to occur on the sliding surface of the magnetic recording medium to a size of 4 μm or less.

[0038]

According to the method of manufacturing a magnetic head of the present invention, the processing time required for processing the contact width of the magnetic head is greatly shortened to improve the grinding processing efficiency, and the magnetic head is generated on the sliding surface of the magnetic recording medium. There is a tendency for edge deficiency to be 4
By controlling to less than μm, the damage of the magnetic recording medium caused by the edge chipping is prevented, the clock generated by the powder drop of the magnetic recording medium is reduced, and the yield and reliability of the product are greatly improved. It becomes possible.

[Brief description of drawings]

FIG. 1 is a perspective view schematically showing a magnetic head according to the present embodiment.

FIG. 2 is a plan view schematically showing a sliding surface of a magnetic recording medium of the magnetic head in which an edge chip has occurred.

[Explanation of symbols]

 1, 2 Magnetic core half body 3 Guide groove 4 Winding groove 5 Metal magnetic film 6 Glass material 7 Width groove 11 Magnetic core a Magnetic recording medium sliding surface g Magnetic gap

Claims (3)

[Claims] 1. When performing a contact width process for securing a contact width with respect to a magnetic recording medium on a sliding surface of a magnetic recording medium of a pair of magnetic core half blocks butted against each other via a gap film. Using the whetstone having a grain size of # 3000 to # 4000, the above-mentioned contact width processing is performed at a grinding speed of approximately 250 mm / min and a peripheral speed of 5000 m / min to 6000 m / min. A method for manufacturing a characteristic magnetic head. 2. The method of manufacturing a magnetic head according to claim 1, wherein the grindstone is a resin bond grindstone. 3. A magnetic head according to claim 1, wherein a metal magnetic film made of a soft magnetic metal material is formed on each of the abutting surfaces of a pair of magnetic core half blocks constituting the magnetic core block. Manufacturing method.