JPS6230934A - Evaluation method and apparatus for magnetic disc - Google Patents

Abstract

PURPOSE:To obtain head/disc combining conditions excellent in the life and durability of the head and disc, by measuring the force received by the head to evaluate the dynamic characteristic caused by the aging change in the variation range per rotation of the magnetic disc. CONSTITUTION:A flexible disc 10 to be evaluated is mounted on a driver as illustrated. A horizontal force measuring device 30 positions a support arm 31 and the detection axis in the direction of tangent line or the rotation of the disc 10 and the tension force working on the arm 31 is detected with a force detector 32. On the other hand, a vertical force measuring device 40 is also equipped with a mechanism for setting the push of a head 20 to the disc 10 to detect the reaction force, namely, vertical force received by the head 20 from the disc 10 with a force detector 41. Thus, the dynamic characteristic can be evaluated that has been caused by aging change in the variation range per rotation of the disc 10.

Description

[Detailed Description of the Invention] <Field of Application of the Invention> The present invention relates to the evaluation of mechanical details such as the durability of magnetic disks and magnetic heads used in magnetic disk storage devices, and particularly to the evaluation of mechanical details such as durability of magnetic disks and magnetic heads used in magnetic disk storage devices, and in particular, The present invention relates to an evaluation method and apparatus suitable for evaluating the wear and tear of both parts when they come into contact.

<Prior art> In conventional durability evaluation, a flexible disk and a magnetic head are brought into contact, a signal is recorded, and changes in the recorded signal level and the number of repeated contacts are visually measured. A lifespan test was conducted based on the number of times of contact. Although this method is excellent in that it can measure the actual usable life including signal attenuation, it has the following problems.

In other words, this method can only provide comprehensive results and cannot grasp the factors that govern durability, so although it is effective for quality control of magnetic disks, it does not provide any information regarding improvements in (a).

By the way, in order to improve the durability f1 of a flexible disk medium, it is necessary to examine other physical quantities such as mechanical properties. Kagaru durability 1 (1 R'l' fill+
i'l (il to 'ru)■'value method]ノ,
324 is fixed at the other end of the arm, and press it against the rotating magnetic disk with a predetermined load in the perpendicular direction. Measures changes in the coefficient of friction, increases in the slip-stick phenomenon, and changes in surface irregularities due to the occurrence of scratches, and based on the measurement results, determines whether the wear resistance of the surface of the magnetic eye disk is good or bad. A covering technique is disclosed in Japanese Unexamined Patent Publication No. 148135/1983. However, with the technology disclosed in Japanese Patent Application Laid-Open No. 59-148135, when the disk surface does not change even if the front vehicle changes, such as with a hard disk, the relationship between durability 1 (1, friction coefficient, etc.) becomes clear. , the intended purpose is achieved, but in the case of flexible disks, there is a problem below: In the case of flexible disk media, due to the presence of localized spots of residual overlapping strain during media formation,
Even if it is possible to press the head with a predetermined load against the rotating flexible disk, the action and reaction that occur between the head and the medium change with the period of the flexible disk. Therefore, it is not possible to determine the relationship between the sliding characteristics, wear resistance, and durability between the magnetic head and the flexible disk, and to determine whether the wear resistance is good or bad.

<Object of the Invention> The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to accurately measure the dynamic characteristics, abrasion resistance, durability, and other mechanical characteristics of a flexible magnetic disk and head. The purpose of this invention is to provide a magnetic disk evaluation method and apparatus that can be easily evaluated.

“Structure and operation of the invention” The above objects are achieved by the invention as follows.

That is, the present invention is a magnetic disk evaluation method in which a flexible magnetic disk is slid against a head at a predetermined speed to evaluate the internal mechanical information f[. The first invention is a magnetic disk evaluation method characterized in that the sliding characteristics are evaluated based on the temporal change in the fluctuation range of the magnetic disk. J flow type force measuring means for measuring the horizontal force in the direction of rotation parallel to the pneumatic disk;
A second aspect of the present invention provides a magnetic disk evaluation apparatus characterized by comprising a vertical force measurement stage for measuring a normal force in a direction perpendicular to the magnetic disk that is applied to the head.

The present invention described above is based on the general dynamics of the sliding surface history of the magnetic disk or the head. It was developed to enable stable and accurate measurement of characteristics.

Here, the mechanical properties include the characteristics of the magnetic disk and the head, such as touch, slipperiness, and friction, mutual wear resistance based on this, and wear due to layered motion.

Contains various special bamboos with a durability of 10%.

J-3, the head bearing (J force) is divided into a horizontal force parallel to the magnetic disk surface and in the rotating direction corresponding to the frictional force, and a vertical force perpendicular to the magnetic disk surface corresponding to the head load in the direction of By detecting them separately and measuring the subtle changes in each variation, the sliding characteristics of the magnetic disk can be grasped.In particular, horizontal force can be used to sensitively and stably evaluate the durability, or mechanical life, of the magnetic disk. can.

Hereinafter, details of the present invention will be explained based on examples and with reference to the drawings.

FIG. 1 is a plan view of the head section of an embodiment of the device of the present invention, and FIG.
The figure is a side view thereof.

The illustrated example is a modified head section of a commercially available floppy disk drive, and the drive section is not shown.

In the figure, reference numeral 10 denotes a flexible disk to be evaluated, which is mounted on a drive device (not shown) and driven at a predetermined rotational speed in the direction of the arrow in the figure. A head 20 is attached to the tip of the support arm 31 of the horizontal force measuring means 30.

By the way, the horizontal force measuring means 30 consists of a support arm 31 that supports the head 20 and a force detector 32 that detects the force acting on the support arm 31. Connector 3 linearly connects support arm 31 made of a spring.
The support arm 31 and the detection shaft 32a are directly connected to each other by the support arm 31 and the detection shaft 32a in parallel with the disk 10 in the rotational direction, that is, in the tangential direction.
It is arranged so that the fields are planted. i.e. force detector 3
2, the tensile force acting on the support arm 31 is detected. Note that the force detector 32 is mounted on the pedestal 50 of the device.
The pedestal 3 of the position setting mechanism consists of a pedestal 36 that is attached to a support 34 installed in the micro gauge 35 in a direction perpendicular to the disk (up and down in the figure) so that its position can be adjusted.
It is fixed at 6. Therefore, the force detector 32 and the support arm 3
1 can be integrally adjusted in position in the vertical direction as shown in the figure.

Further, on the back side of the head 20, on the upper side in the figure, a vertical force measuring means 40 for detecting the force acting on the head 20 in a direction perpendicular to the disk 10 is installed. Vertical force measuring means 40
This also serves as a setting mechanism for setting the pushing amount of the head 20 onto the disk 10, and a force detector 41 with a pressing tool 42 provided at the tip of the detection shaft 41a serves as a position setting mechanism for the horizontal force measuring means 30. The pressing tool 42 is fixed to a pedestal 45 of a position setting means which is made up of a completely similar support 43, a microphone gauge 44, and a pedestal 45, and which enables the position of the pedestal 45 to be adjusted in the vertical direction.
is provided so as to come into contact with the back surface of the head 20.

That is, the amount by which the head 20 is pushed into the disk 10 can be set accurately by the micro gauge 44, and the reaction force, that is, the vertical force, which the head 20 receives from the disk 10 can be detected by the force detector 41. In addition,
As the force detectors 32 and 41, commercially available load cells, specifically Minebea (U gauge, type UT-100GR, manufactured by Minebea Co., Ltd.) were used.

Note that 11 and 12 in the figure are support pads that support the disk 10, and known pad materials and liner materials can be used as they are, but if the disk 10 is a metal thin film medium,
Raised fabrics such as Hi-Lake (registered trademark) are preferably used.

The output signals of the force detectors 32 and 41 are led to a recorder (not shown) and recorded. Note that a data processing device may be used instead of the recorder to collect the data as digital values.

According to the above configuration, the surface pressure of the head 20 against the disk 10 can be arbitrarily set by the above-mentioned position setting means,
Moreover, it is possible to measure periodic pressure fluctuations caused by the activities of the head 20 and the disk 10 up to the response speed of the force detectors 32 and 41.

In addition, since the load on the head 20 is as light as a few grams, the support arm 3
It is possible to improve the flexibility of the structure of the leaf spring constituting the disk spring 1 and to follow a high frequency response. It is possible to measure up to The details of the method of the present invention will be explained below with reference to measurement examples using the above-mentioned apparatus.

[Measurement Example 1] The flexible disk 10 to be measured is a long 501
NiFeMO permalloy soft magnetic film, 20w, was applied to the surface of a 1m thick polyester film using the facing target sputtering method.
A Co-Or@directly magnetized film and a protective film made of t%Cr were 00 Stt m and 0.2 μm thick, respectively.

This is a perpendicular disk F1 made by punching out a 51/4 floppy disk shape from a known perpendicular magnetic recording medium continuously formed to a film thickness of 0.02 μm.

As the head 20, AlTiC (Δn203 ・Ti
C) is used for the slider part, and Co Zr Nb is made of width Tw: 2s and ll'J thickness Tm: 0.8uTrt.
A main magnetic pole head 111 in which a main magnetic pole is formed of a metal-containing film and the tip of the head is machined into a spherical shape with a radius of curvature of 30 mm.
゜Equipped with 1M of main magnetic pole heads 1-12 machined into a semicircular shape with a radius of curvature of 30 mm in the running direction of the head/medium, and in combination with the same auxiliary magnetic pole, the well-known auxiliary VI single-pole excitation VI1 type double-straight head double, recording and reproducing. I made it happen. The relative sliding speed between the head and the medium is set to 2 m/s, and the head H1, t-1
2 and the above-mentioned durability of the vertical disk + (I).
Let the push-in suspension of 0 be d (adjustment), and let the push-in suspension d be ('
The force acting on the head 20 in the vertical direction is a vertical force Pp,
When evaluated as horizontal force Pp in the horizontal direction, Fig. 3,
Figure 4 was obtained.

The horizontal force Ph when d = 0.3 m/m showed periodic fluctuations as shown in Figure 5.

For the case of d = 0.3 m/H, head l-11
.

After recording at 201 < frpi (kiloflux spur index) using H2, the playback signal level becomes 3.
When we measured the relationship between the number of repetitions N that resulted in a decrease in dB, we found that head H1 had more than 10 million passes, and head 11
The platform of 2 is less than 1 million passes, I,=. From the above, it is possible to stably measure the weight l°1 force and horizontal force using Kihi ■.
It can be seen that the mechanical 1h properties of the disk or head can be measured.

[Measurement Example 21 Ly J is the same as the above-mentioned Yo 1 magnetic pole head 1-11 except that the head 20 is made of carbon-based material for a part of the sliter.
Using the i4 main pole head lI3, the vertical disk "1
was evaluated in the same manner as in Measurement Example 1 ('I-U').

Fig. 6 (△) (II) shows the case of main pole head 1 (3).
The number of rotations is 5000 to change the vertical force P Il and horizontal force ph.
times ((A) figure) and 110,000 times (([3) figure)].
Changes in vertical force Pp and horizontal force [river] in the case of sliding number 5
000 times ((Δ) figure) and 1 million times (([3) figure)] are shown. Vertical disk "1 head l-11.

I checked the durability M of l-13 and found that head 113. Disk [1 combination Vc- is 1 for both head and disk.
After 10,000 times of sliding test, the occurrence of l;I: :ls was observed. .

Also, the vertical force Pp and the horizontal force [) 11 have a variation [1]ΔPp which is the difference between the maximum value and the minimum value during one rotation of the disk.

Focusing on △P l), after 110,000 passes each, (1
Although 1S has increased, Δph in particular has doubled, which is consistent with deterioration of the sliding surface. The waveform within one revolution of the disk also fluctuates with the horizontal force ph, which is consistent with deterioration of the sliding surface. On the other hand, in the combination of head 1" 1 and disk 1,
Head L-11, disk F1 even after 1 million sliding movements
No scratches or peritoneal movements were observed on either side.

In addition, the above-mentioned fluctuations [1] △Pp and △Ph hardly change, and the waveform within one rotation of the disk also shows almost no change in the low frequency component, apart from the high frequency component, and the initial 1llll sliding characteristics are maintained. You can see that

From the above, it can be seen that the surrounding motion characteristics can be stably and accurately measured based on the fluctuation range of the horizontal force Pp during one rotation of the disk and the change over time of the waveform. The detection sensitivity is particularly high for horizontal force ph.

"Measurement Example 3" Using the vertical head 1-11 used in Measurement Example 1, the flexible vertical disc 1 of Measurement Example 1 and the stomach vertical disc 1-2 of the strip 1 created with the same configuration were as follows: The relationship between the measurement results according to the present invention and the measurement results of reproduction demagnetization was investigated. Figure 8 shows the measurement results of the time-dependent changes in reproduction demagnetization of vertical disks F1 and F2. Fluctuations in F1.F2 horizontal force 1] 1) and vertical force pp [1]
ΔP11. The measurement results of the change in Δpp over time are shown. The horizontal axis in both figures is the number of disk passes.

As shown in Figure 9, the reproduction demagnetization of vertical disk ``1'' is 600
However, after 1 million passes, the reproduction demagnetization of vertical disk F2 increases in proportion to the number of passes, and the output decreases accordingly. As shown in Fig. 9, even if the number of passes increases, the sliding characteristics of the vertical disk F1 do not change as much as the horizontal force fluctuation 1]△P]1. On the other hand, the horizontal force fluctuation [IJ△Pb] rapidly increases after 1 million passes in the horizontal dynamic characteristics of the vertical disk [22], which agrees well with the time-dependent change in regenerative demagnetization shown in Figure 8. According to the evaluation method according to the present invention, a significant difference in the durability of the disk can be seen from the initial stage of deterioration from the horizontal variation 1].

Also, if we are blind to the fluctuation width △Pp of the vertical force of disk F2,
It fluctuates widely at the beginning of the measurement, making it possible to detect durability (l+) at an early stage.Furthermore, in the medium of disk F2, as shown in FIG. On the other hand, the horizontal force fluctuation width △Ph is disk F1
There is no noticeable difference between the disc F2 and the disc F2.
2 is slightly smaller than that of disk F1.

Disc F1. The difference in the number of passes in the playback area at F2 (Figure 9) becomes noticeable when the number of passes exceeds 1 million, whereas according to the evaluation method according to the present invention, as shown in Figure 9, the disc F1. During F2, a noticeable difference appears from the beginning in the number of passes. Head l-11 and disk F shown in FIG. 9, 1. It is considered that there is the following relationship between the sliding condition with F2 and durability. The Vickers hardness of the head 1-11 is 2000, whereas the disk F1. Surface hardness of the medium including the protective layer of F2 l-1sv
It has been confirmed by comparison with materials of various Vickers hardness that 100<Hsv<2000. When we examined the sliding condition of disk F1 and head 1''1 after 6 million passes, we found that there were no sliding scratches on head 1''1, and that there was almost no change in the surface condition of disk F1. observed
It was r. From this, in the case of the disk F1, the fluctuation of the vertical force in the sliding state with the head H1 1]ΔPp
In other words, the perpendicular impact stress variation ΔPp is interpreted to be less than the impact force that destroys the thin layer including the protective layer of the medium. On the other hand, when the sliding condition of disk "2 and head 1" 1 was examined after 3 million passes, no sliding scratches were found on head 1"1, but head 1 of disk "2"
-11 The sliding part had clear signs of sliding and scratches. In other words, in the case of disk F2, as can be seen from Figure 9, the vertical impact stress fluctuation ΔPp is large and decreases as the number of passes increases in the range of about 200,000 passes. The i layer including the holder 11'J of the disk F2 is subjected to impact stress fluctuations ΔPp in the vertical direction, resulting in changes in the state of the permalloy and C0-Cr layer gold alloy crystal structures constituting the thin layer. , when the number of repetitions of the vertical impact stress fluctuation △Pp exceeds 1 million, a crack appears in the 1 threatening part of the head 1''1, and the horizontal force changes 11]
Δph In other words, it is interpreted that the horizontal impact stress fluctuation ΔPh suddenly changes.

As described above, by using the evaluation method according to the present invention, it is possible to not only accurately and quickly evaluate the durability between the head and the disk from the temporal changes in the fluctuation ranges ΔPh and ΔPp of horizontal force and vertical force, but also to It becomes possible to control the quality of durability of the disk/head combination, including the allowable range of crystal distortion and mechanical toughness of thin films that are specific to vacuum deposition methods such as sputtering and vapor deposition.

[Effects of the Invention] As is clear from the above explanation, the surrounding motion characteristics between the head and the disk can be determined by evaluating the range of variation of the vertical force and horizontal force acting on the head during one revolution of the disk. ,
This will have the ripple effect of creating technical conditions for a combination of heads and disks that can quickly and accurately evaluate the lifespan of heads and disks and have excellent durability.

[Brief explanation of drawings]

Figures 1 and 2 are plan and side views of the head section of the embodiment of the device of the present invention; Figures 3, 4, and 5 are dimensional graphs showing the results of measurement example 1; 7 is a waveform diagram of a measurement signal showing the results of measurement example 2, and FIG. 8 is a waveform diagram of a measurement signal. FIG. 9 is a graph showing the results of Measurement Example 3. 10: Disk 20: Head 30: Horizontal force measuring means 40: Vertical force measuring means
ro ) 1] Age 5

Claims (1)

[Claims] 1. A method of evaluating mechanical properties by sliding a flexible magnetic disk against a head at a predetermined speed, in which the force exerted by the head is measured and the fluctuation during one revolution of the magnetic disk is evaluated. A magnetic disk evaluation method characterized by evaluating mechanical properties based on changes in width over time. 2. The method for evaluating a magnetic disk according to claim 1, wherein, among the forces, at least a horizontal force parallel to the magnetic disk surface and in the direction of rotation thereof is measured. 3. Among the forces, at least the normal force in the direction perpendicular to the magnetic disk surface is measured in claim 1 or 2.
Evaluation method for magnetic disks described in Section 1. 4. A horizontal force measuring means for measuring horizontal force parallel to the magnetic disk surface and in the direction of rotation of the magnetic disk, which is applied to the head in a magnetic disk device that evaluates mechanical characteristics by sliding a flexible magnetic disk against a head at a predetermined speed. 1. A magnetic disk evaluation device comprising a vertical force measuring means for measuring a vertical force in a direction perpendicular to a magnetic disk surface which is applied to a head. 5. The head is attached to the tip of a support arm made of an elastic material that is supported approximately parallel to the magnetic disk surface, and the position in the vertical direction of the magnetic disk surface is set by a setting mechanism provided behind the head. The magnetic disk evaluation device according to claim 4, which is capable of performing the following: 6. The detection parts of the horizontal force measuring means and the vertical force measuring means are both load cells, and the support arm and the setting head of the setting mechanism are supported by the load cells.
The magnetic disk evaluation device described in Section 1. 7. The magnetic disk evaluation device according to claim 6, wherein the load cell and support arm of the horizontal force measuring means are positionally adjustable in a direction perpendicular to the magnetic disk surface.