JPS6257117A - Manufacture of magnetic head - Google Patents

Abstract

PURPOSE:To smooth an edge of a groove so that a medium is not flawed, by driving to rotate a grinding member provided with a grinding line consisting of an abrasive, which has been formed in a shape of a concentric circle on a substrate, running a magnetic head against the grinding line, and forming a groove on a medium sliding surface of the magnetic head. CONSTITUTION:In the beginning, grooves 6-8 are not formed on a magnetic head, a sliding surface of the magnetic head is constituted, and thereafter, a shape of the sliding surface is put in order to a desired shape by a method of tape lapping, etc., and also depth of a gap of magnetic poles 4, 5 is formed to a desired value. Subsequently, a discoid grinding member is used for forming the grooves 6-7 of the head sliding surface. The grinding member is provided by sticking in a shape of a concentric circle an abrasive consisting of various kinds of well-known abrasive grains, of polishing lines 13 of a concentric circle shape between then innermost peripheral part 12 and the outermost peripheral part 11, of a base material 10 consisting of a flexible material having a mechanical characteristic being equal to that of a video floppy disk. When working the grooves 6-7, they are formed by making the rotary head on which the sliding surface has been formed to a desired shape coincide with the grinding line 13 of the base material 10 and sliding it.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method of manufacturing a magnetic head, and more particularly to a method of manufacturing a magnetic helad in which grooves are formed on the medium sliding surface of a magnetic head.

[Prior Art] In recent years, video floppy devices for recording and reproducing still images have been put into practical use, but in this type of device, image information equivalent to one field of a video monitor screen is stored in one revolution of a magnetic track. 2 fields, that is, 1 frame's worth of image information is recorded on 2 tracks.When playing back 1 frame of images recorded over 2 tracks, the image information is recorded every 1/60 seconds. It is necessary to switch tracks to perform playback.Therefore, a magnetic head that performs this field switching is 1/60
A two-channel head is advantageous because it does not require track movement every second and can switch fields simply by switching the reproduction signal.

However, in this case, 2. The magnetic head must be able to access the wooden tracks at the same time, and a good head touch over two tracks is required. According to the standards for video floppy disks, its tracks are 60 mm wide, the track spacing is 40 IL wide,
Therefore, good spacing of the magnetic head (distance between head and medium) must be obtained over a width of at least 160 ILm. Generally, practical spacing values are as narrow as O, lu, -. is necessary.

However, as the area of the magnetic head in the track width direction increases, the positive pressure generated in the air lubricating layer between the head and the medium increases, and this force acts as a repulsion force on the media, causing the - In the case of a flexible medium, deformation of the medium occurs, making it impossible to obtain a sufficiently narrow spacing, resulting in an increase in spacing loss.

Therefore, in a patent application filed on the same day as the present application, the applicant
We proposed a technology to provide good spacing by providing grooves on the sliding surface of the magnetic head that are approximately parallel to the sliding direction of the medium, thereby reducing the positive pressure of the air lubricating layer.

[Problems to be Solved by the Invention] FIG. 6 shows the medium sliding surface of a two-track magnetic head for a video floppy disk. The magnetic core portion is formed as a thin film on the substrate 1-, and only the magnetic pole portion 4.5 is exposed to the sliding surface. Further, a reinforcing plate 2 is bonded and fixed to the sliding surface via an adhesive layer 4.

Additionally, three grooves 6-8 are provided to reduce the positive pressure in the air lubrication layer between the medium and the magnetic head. The width of these grooves is set to about 5 to 30 mm, and the depth is set to 1>m or more from the sliding surface.

As a method for forming such grooves, cutting with a cutting tool has been known. However, processing using a dicing saw has the problem that chipping, cracking, etc. are likely to occur during processing. As shown in FIG. 6, the head is composed of a composite material made of various materials such as a substrate, an adhesive layer, and a reinforcing plate, and chipping and cracking are particularly likely to occur at the boundary between the materials. In addition, as shown in Figure 6, in the groove between the spacing 4OIL layer and the adjacent magnetic pole 4.5, the groove and the magnetic pole are very close to each other, so if chipping or cracking occurs during groove processing, the magnetic pole part will be damaged and recording will occur. There is a possibility that the playback characteristics will deteriorate.

Further, when machining is performed using a guising tool, the edges of the groove tend to be sharp, and there is a risk of damaging the medium when the medium slides.

Furthermore, there is the problem that it is difficult to ensure the accuracy of the depth of the groove in the guissing tool. As mentioned above, the groove depth ll-
It may be necessary to set it to about 1 OJL, but it is very difficult to accurately position the magnetic head to be processed in such a dimensional range with respect to a dicing saw. Therefore, there is a problem that the depth of the grooves formed tends to vary, and the width of the grooves also tends to vary depending on the shape of the grindstone of the grinding tool. Therefore, variations occur in the pressure control in the air lubricating layer, making it difficult to control the spacing to a desired value.

Furthermore, groove machining by conventional methods, not limited to Guising Two, is effective only before use of the magnetic head, and it has been impossible to form grooves after the head has been used.

Even if grooves are formed on the media sliding surface, the depth of these grooves may change due to wear of the head, and as the media slides, foreign matter such as binder and magnetic powder may clog the grooves, causing the grooves to become slippery. It is possible that the patient will not be able to perform the pacing control function,
It would be desirable to be able to repair and shape the grooves even after the magnetic head has been used. However, with conventional methods, such repair work was difficult and required troublesome work procedures such as removing the magnetic head. .

[Means for Solving the Problems] In order to solve the above problems, the present invention provides an abrasive member having abrasive lines made of an abrasive material formed concentrically on a disc-shaped base material. A configuration was adopted in which grooves were formed on the medium sliding surface of the magnetic head by rotating the magnetic head and running the magnetic head against the polishing line.

[Function J] According to the above configuration, the edges of the grooves are obtuse-angled compared to processing with a conventional dicing saw, so cracks and chipping are less likely to occur in these areas, and the dimensions of the grooves are easier to polish. Since it depends on the shape of the line, the grooves can be formed on the sliding surface with high accuracy through a simple manufacturing process.

[Example] Hereinafter, the present invention will be described in detail based on the example shown in the drawings.

The method of forming the groove in the first embodiment of the present invention is as follows.

First, a magnetic head is manufactured by a normal process. That is, in the magnetic head of FIG. 6, n6 to n84 are not formed, but a magnetic helad sliding surface is formed, and then the shape of the sliding surface is adjusted to a desired shape by a method such as tape wrapping, and then the magnetic poles are formed. Form the gap depth of 4.5 to the desired value.

Next, in this embodiment, a disc-shaped abrasive member as shown in FIG. 1 is used to form the grooves 6 to 7 on the sliding surface of the head 7. In FIG. 1, reference numeral 10 denotes a video floppy disk or a base material made of a flexible material having mechanical properties equivalent to the video floppy disk. A polishing line 13 is provided concentrically between the innermost peripheral part 12 and the outermost peripheral part 11 on the base material 10 . The abrasive line 13 is constructed by concentrically adhering abrasive material made of various known abrasive particles.

FIG. 1 shows a case where three polishing lines 13 are provided to form three grooves as shown in FIG. Grooves are formed on the magnetic helad sliding surface by sliding the magnetic head formed on the base material 10, which is rotated at a predetermined number of rotations, so that the position of the polishing line 13 of the base material 10 matches the predetermined position of the head. .

In order to accurately position the magnetic head, in this embodiment, a magnetic track 14 is provided concentrically outside the polishing line 13, and a predetermined signal is magnetically recorded thereon.

Therefore, the magnetic head to be processed is fixed to a carriage configured similarly to the head seek mechanism in a magnetic disk device, and while the signal recorded on the magnetic track 14 is first reproduced by the magnetic head to be processed, the posture of the head and the track are adjusted. The head is accurately positioned at the polishing line 13 by adjusting the position and then moving the head by a predetermined amount in the inner circumferential direction.

Thereafter, the magnetic head is brought into contact with the polishing line 13 and allowed to slide on the polishing line for a predetermined period of time.

By the method described above, grooves having the same depth as the thickness of the polishing line can be formed on the sliding surface of the head.

FIGS. 2 and 3 respectively show a cross section of the abrasive line 13 of the abrasive member used in this embodiment and a cross section of the groove formed thereby. First, as shown in Figure 2, polish the j! 1
No. 3 is formed to have a convergence of about 15 JLm and a thickness of about 51 Lm. The cross section of the groove ground by this grinding line 13 is as indicated by reference numeral 17 in FIG. The shape of the groove is almost the same as the shape of the polishing line 13, but due to slight positional fluctuation, the edge part 1
9 has a rounded shape compared to the case where it is a guising tooth. As a result, the groove 17 whose maximum width tends to be slightly wider than the width of the polishing line 13, and which has a width of about 201 Lm in this example, was formed.

According to the embodiments described above, there are fewer occurrences of chipping and cracking than in the conventional processing using a cutting tool, and edges are formed smoothly, so there is no possibility of damaging the medium.

Further, since the depth of the groove is determined by the thickness of the polishing line, and the width is also approximately determined by the width of the polishing line, there is an advantage that there is little variation in dimensions.

Furthermore, by making the disk-shaped abrasive member have the same mechanical properties as the recording medium, the grooves can be formed along the sliding surface of the spatula, so they can have a constant depth regardless of the position of the sliding surface. It is possible to obtain grooves. Furthermore, by forming magnetic tracks for positioning on the abrasive member, highly accurate groove processing can be easily performed.

In the above example, a magnetic track for positioning is formed on a disc-shaped abrasive member, but the abrasive member and the disc for detecting the reference position may be separate members. Similar alignment accuracy can be achieved by adjusting the head to a predetermined position with a magnetic disk, shifting, replacing the abrasive member, and performing sliding again.

Next, FIG. 4 and FIG. 5 show a second embodiment of the present invention.

FIG. 5 shows the sliding surface of a 50-channel thin-film magnetic head for a video floppy disk that can perform recording and reproduction on 50 tracks simultaneously.

The magnetic head shown in FIG. 4 is constructed by forming a magnetic core as a thin film on a substrate 1, similar to the magnetic head shown in FIG. The only difference is the number of tracks, and the basic configuration is almost the same as the magnetic head shown in FIG. Here, the same members as in FIG. 6 are given the same reference numerals.

In such a magnetic head, the area of the sliding surface becomes very large, so the positive pressure of the air lubricating layer generated when the medium slides also becomes large, making it very difficult to obtain narrow spacing. Therefore, such a head has grooves 6 on the sliding surface.
Providing .about.8 is very effective in reducing the spacing.

In this embodiment as well, when forming the grooves 6 to 8, a disk-shaped abrasive member as shown in FIG. 5 is used. The abrasive member shown in FIG. 5 has substantially the same construction as that shown in FIG. 1, with 51 abrasive lines 43 formed between the innermost periphery 12 and the outermost periphery 11 of the disk. The arrangement pitch of these polishing lines 43 is loO#Lm, which is the same as the track pitch of a video floppy disk, and the positions in the radial direction are also set at positions corresponding to both ends of the 5o track and the middle part of the track.

According to this embodiment, the procedure for forming grooves on the head sliding surface is as follows.

First, prepare a magnetic disk on which 50 racks worth of signals have been recorded in accordance with the video floppy disk standard, slide the magnetic head to be processed in the same manner as above onto the rotationally driven magnetic head, and observe the reproduced signal from the head. while adjusting the track direction and attitude of the head.

Thereafter, the magnetic disk is replaced with the abrasive member shown in FIG. 5, and the magnetic head is brought into sliding contact with the rotationally driven abrasive member.

By the method described above, even in a multi-track magnetic head, grooves can be formed on the medium sliding surface at one time, and almost the same effect as in the first embodiment can be obtained.

Two embodiments have been described above, but in any of the embodiments, the groove processing method according to the present invention can be applied not only before use of the head but also during use. That is, as described above, the magnetic head wears out with use, and the depth of the groove decreases accordingly. One possible countermeasure to this problem is to initially set the depth of the groove deep to allow for wear, but if the depth is set too large with this method, magnetic powder, binder, dirt, etc. Sometimes the grooves become clogged, reducing the efficiency of the grooves. Furthermore, since the rate of wear differs depending on the position on the sliding surface, the depth of the grooves also becomes non-uniform, causing the problem that the effectiveness of the grooves changes depending on the position on the sliding surface.

However, according to the present invention, since an abrasive member having the same shape as the magnetic disk is used, groove machining can be performed even while the magnetic head is in use, and the shape of the groove whose function has deteriorated due to wear or clogging can be restored. Is possible.

For example, in the case of the second embodiment, after the magnetic head has been used for a certain period of time, the video floppy disk may be replaced with an abrasive disk, and the magnetic head may be positioned and moved in the same manner as in normal recording and playback. As a result, the shape of the grooves of the magnetic head is restored to its initial state, and the positive pressure of the air lubricating layer is reduced to restore good spacing.

Further, according to the present invention, the depth of the groove provided in the magnetic head does not necessarily need to be increased in anticipation of wear, so that the groove shape suitable for spacing control can be maintained at all times.

[Effects] As is clear from the above description, according to the present invention, a polishing member provided with polishing lines made of an abrasive material formed concentrically on a base material is rotatably driven, and a polishing member is rotated with respect to the polishing lines. Since a configuration is adopted in which grooves are formed on the medium sliding surface of the magnetic head by running the magnetic head, the following excellent effects are achieved.

Compared to processing using a conventional dicing saw, the edges of the grooves are smoother, so there is no damage to the media, and there is less occurrence of chipping or clutter.

The dimensions of the groove are determined approximately by the shape of the abrasive line, and the processing accuracy of the groove is good.

Since a disc-shaped abrasive member is used, the head can be easily and precisely positioned using conventional head positioning technology for magnetic recording and reproduction. Processing such as restoring the shape of the groove can be performed even after the start of use.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the structure of the polishing member used in the first embodiment of the present invention, 2rgJ is a sectional view showing the shape of the polishing line in FIG. 1, and FIG. FIG. 4 is a cross-sectional view showing the shape of the groove formed by the abrasive member, and FIG. A front view showing the shape of the magnetic head to be processed, Fig. 5 is an explanatory diagram showing the configuration of the abrasive member used for processing the magnetic head in Fig. 4, and Fig. 6 is a magnetic head for a two-track video floppy. FIG. 3 is a top view showing the sliding surface of the head.

Claims (1)

[Claims] 1) By rotating an abrasive member provided with an abrasive line made of a circular abrasive material on a disc-shaped base material, and causing a magnetic head to run along the abrasive line. A method of manufacturing a magnetic head, comprising forming grooves on a medium sliding surface of the magnetic head. 2) The method of manufacturing a magnetic head according to claim 1, wherein the abrasive member has the same shape as a magnetic recording medium used for recording and reproduction of the magnetic head. 3) A patent claim characterized in that a circular magnetic track is provided on the surface of the abrasive member, and the magnetic head is positioned with respect to the abrasive line by reproducing a recorded signal on the magnetic track by a magnetic head undergoing processing. A method for manufacturing a magnetic head according to item 1 or 2.