JP2000343565A - Mold apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mold a good disk substrate having no flaw on the surface thereof by suppressing the generation of an abraded powder between to the member moved toward a fixed mold and the member adjacent thereto the utmost and certainly preventing the abraded powder from penetrating in a cavity when the abraded powder is generated. SOLUTION: In a mold apparatus, the size of a gap formed between the member moved to a fixed mold and the member adjacent thereto like the gap S2 between a first injector 16 and a movable mold 12 is set to 15-40 μm and the gap S2 is evacuated. By this constitution, the generation of an abraded powder in the gap S2 can be effectively suppressed and, even if the abraded powder is generated, it can be effectively prevented that the abraded powder penetrates in a cavity to exert adverse effect on the molding of a disk substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold apparatus for molding a resin disk substrate.

[0002]

2. Description of the Related Art Hard disk drives have been widely used as storage devices for computers. This hard disk drive uses, as a recording medium, a magnetic disk in which a signal recording layer is formed on a disk substrate made of a metal plate such as aluminum whose surface has been polished with high precision, and on a signal recording area of the magnetic disk, Flying the flying slider with the magnetic head at a predetermined flying height,
Signal writing and / or reading is performed.

[0003] By the way, in this hard disk drive, a price reduction has been demanded as the hard disk drive is widely spread. In order to meet the demand for lowering the cost, application of a resin disk substrate that can be manufactured at a lower price than an aluminum substrate is being studied as a disk substrate of a magnetic disk.

[0004] Further, in a disk-shaped recording medium (hereinafter, referred to as an optical disk) in which an information signal is written or read using light, such as a read-only optical disk, a magneto-optical disk, and a phase change optical disk, etc. A resin disk substrate is used as the disk substrate. In an optical disk drive using this optical disk as a recording medium, in order to increase the recording capacity, a flying slider on which an optical head is mounted is floated above a signal recording area of the optical disk to write and / or write signals. A technique for performing reading has been proposed.

[0005] Resin disk substrates used for these magnetic disks and optical disks are generally manufactured by injection molding a resin material that has been heated and melted. Hereinafter, a process of manufacturing a resin disk substrate used as a disk substrate of a magnetic disk or an optical disk will be described.

When manufacturing a resin disk substrate used for a magnetic disk or an optical disk, first, a resin material in the form of a pellet is charged into an injection molding machine. The resin material supplied to the disk substrate manufacturing apparatus is dried by a hopper, and after being sufficiently removed of water, supplied to a cylinder, where it is heated and melted. The heat-melted resin material is supplied to a mold device provided in the injection molding machine.

As shown in FIG. 12, a mold apparatus 100 provided in an injection molding machine has a fixed mold 101 for molding one main surface of a disk substrate and a movable mold for molding the other main surface of the disk substrate. 102 and an outer peripheral mold 103 for molding the outer peripheral portion of the disk substrate.

The fixed mold 101 is formed in a disk shape having a center hole 101a, and is provided in a state fixed to the main body of the injection molding machine. And fixed mold 1
01, a sprue bush 1 which forms a path for the molten resin material and receives a punch described later to assist in punching out the center hole of the disk substrate.
04 is inserted.

The movable mold 102 is formed in a disk shape having a center hole 102a, and is provided so as to be movable in a direction approaching and separating from the fixed mold 101. And
The molding surface 102b of the movable mold 102 is
01 is arranged so as to face the molding surface 101b. A punch 1 for punching a center hole of the formed disk substrate is provided in a center hole 102a of the movable mold 102.
05, a first ejector 106 located on the outer peripheral side of the punch 105 for taking out the molded disk substrate from the mold apparatus 100, and a through hole provided at the center of the punch 105, A second ejector 107 is provided for taking out, from the mold apparatus 100, a portion of the resin material corresponding to the center hole of the disk substrate punched by the punch 105.

The outer peripheral mold 103 is formed in an annular shape, and is attached to the outer peripheral side of the movable mold 102. The outer peripheral die 103 comes into contact with the fixed die 101 when the movable die 102 is moved to a position close to the fixed die 101. At this time, the molding surface 10 of the fixed mold
A cavity 108 as a closed space is formed between the movable mold 1b and the molding surface 102b of the movable mold 102.

When a resin-made disk substrate is manufactured by the mold apparatus 100 configured as described above, first, the movable mold 102 is moved to the fixed mold 101 side to move the fixed mold 101 and the movable mold. A cavity 108 is formed by the mold 102 and the outer peripheral mold 103. Then, the heat-melted resin material is injected and filled into the cavity 108 via the sprue bush 104.

Next, after the punch 105 is moved toward the fixed mold 101 and the center hole of the disk substrate is punched, the molten resin material injected into the cavity 108 is pressurized in the cavity 108. While being cooled. Thereby, the resin material in the cavity 108 is solidified in a shape reflecting the molding surface 101b of the fixed mold 101 and the molding surface 102b of the movable mold 102,
A resin disk substrate is formed.

When the disk substrate is molded, the movable mold 1
02 is moved in a direction away from the fixed mold 101, and the cavity 108 is opened. Then, the first ejector 106 and the second ejector 107 are moved to the fixed mold 101 side, and the resin material in the portion corresponding to the center hole of the molded disk substrate and the disk substrate punched by the punch 105 is made of metal. Removed from the mold device 100.

[0014]

When a resin disk substrate is formed by the above-described mold apparatus 100, the punch 105, the first ejector 106, and the second ejector 107 are moved to the fixed mold 101 side. Since these members are operated, abrasion powder may be generated between these members and members adjacent thereto as the members move.

The wear powder enters the cavity 108 each time the punch 105, the first ejector 106, and the second ejector 107 are moved. The abrasion powder that has entered the cavity 108 adheres to the surface of the formed disk substrate and causes a protruding defect on the surface of the disk substrate.
Molding surface 101b of movable mold 102 or molding surface 102b of movable mold 102
To cause a concave defect on the surface of the disk substrate.

Therefore, in order to suppress the generation of such abrasion powder, a member such as a punch 105, a first ejector 106, and a second ejector 107, which is operated to move toward the fixed mold 101, and a member adjacent thereto. Between the members,
Although a gap (clearance) having a size of about 10 μm was provided, the generation of abrasion powder could not be sufficiently suppressed with such a clearance.

Further, in order to prevent the abrasion powder from entering the cavity 108, the gap between the member operated to be moved to the fixed mold 101 side and the member adjacent thereto is vacuum sucked. However, since the size of the gap is small, sufficient suction cannot be performed, and it has not been possible to reliably prevent wear powder from entering the cavity 108.

Therefore, the present invention minimizes the generation of abrasion powder generated between a member that is moved to the fixed mold side and a member adjacent to the member and minimizes the generation of abrasion powder when the abrasion powder is generated. An object of the present invention is to provide a mold device capable of reliably preventing powder from entering a cavity and forming a good disk substrate having no defect on its surface.

[0019]

The inventor of the present invention has made intensive studies to achieve the above object, and as a result, has found that a gap between a member moved to the fixed mold side and a member adjacent to this member is reduced. By setting the size to 15 μm or more, the generation of wear powder can be significantly suppressed, and even when wear powder is generated, the wear powder is appropriately vacuum suctioned.
The inventor has found that the wear powder can be reliably prevented from entering the cavity.

Further, the present inventor sets the size of the gap between the member to be moved to the fixed mold side and the member adjacent to this member to a size exceeding 40 μm, so that the molded disk substrate It has been found that large projections are formed on the inner peripheral side of the above, and that an appropriate clamping operation may not be performed.

The mold apparatus according to the present invention has been made based on the above-mentioned knowledge, and has a melting space filled in a closed space formed between a fixed mold and a movable mold. In a mold apparatus for molding a disk substrate by cooling and curing the resin material in the closed space, a moving member provided movably with respect to the movable mold,
The size of the gap between the moving member and the member adjacent thereto is in the range of 15 to 40 μm, and the vacuum suction for vacuum-suctioning the gap between the moving member and the member adjacent thereto. It is characterized by comprising means.

This mold device includes, for example, a punch for punching a center hole of a disk substrate, a first ejector for removing a molded disk substrate from the die device, and a portion punched by the punch. A moving member such as a second ejector for removing the resin material from the mold device is provided. These moving members are provided so as to be movable with respect to the movable mold, and are moved to, for example, the fixed mold side as needed.

In this mold apparatus, the size of the gap between the moving member and the member adjacent to the moving member is set to 15 μm or more. Generation of powder is greatly suppressed. Further, even if wear powder is generated, the gap between the moving member and the member adjacent to the moving member is appropriately vacuum suctioned by the vacuum suction means, so that the wear powder is removed from the fixed mold. It is possible to reliably prevent intrusion into the closed space formed between the movable mold and the movable mold, thereby forming a good disk substrate having no defect on the surface. Since the size of the gap between the moving member and the member adjacent to the moving member is set to 40 μm or less, an inconvenience such as forming a large protrusion that hinders the clamping operation on the disk substrate to be formed is effective. Can be avoided.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

A resin disk substrate 1 used for a magnetic disk or an optical disk is formed by injection molding of a thermoplastic resin material such as polycarbonate or polymethyl methacrylate, for example, as shown in FIG. 1a.

An injection molding machine for manufacturing a resin disk substrate by injection molding a resin material includes, for example, a mold apparatus 10 as shown in FIG. As shown in FIG. 2, the mold apparatus 10 includes a pair of fixed dies 11 and a movable mold formed by molding a metal material into a disk shape and having molding surfaces 11a and 12a opposed to each other. The movable mold 1 includes a mold 12 and an outer mold 13 provided on an outer peripheral side of the movable mold 12.
2 is moved in a direction approaching the fixed mold 11, and when the outer peripheral mold 13 contacts the fixed mold 11, the fixed mold 1 is moved.
A closed space (hereinafter referred to as a cavity) is formed between the movable mold 1 and the movable mold 12.

The fixed mold 11, the movable mold 12, and the outer mold 13 are connected to a cooling mechanism (not shown), respectively, so that the resin material filled in the cavity can be cooled and hardened. .

At the center of the fixed mold 11, a center hole 11b penetrating in the thickness direction is provided. A sprue bush 15 is formed in the center hole 11b of the fixed mold 11 to form a path for the melted resin material and receive a punch described later to assist in punching the center hole 1a of the disk substrate 1. Have been.

One end of the sprue bush 15 is connected to a resin material melting mechanism of an injection molding machine (not shown), and the other end of the sprue bush 15 has a gap S1 in a center hole 11b of the fixed mold 11, as shown in FIG. It is inserted with existence. In the mold device 10 according to the present invention, the size (clearance) of the gap S1 between the sprue bush 15 and the fixed mold 11 is set in a range of 15 to 40 μm. FIG. 3 is an enlarged view of a portion A in FIG.

At the center of the sprue bush 15,
A through hole 15a is provided from one end to the other end, and the through hole 15a of the sprue bush 15 is provided.
Is used to transfer the molten resin material to the fixed mold 11 and the movable mold 12.
And a path for supplying into a cavity formed between the two.

The fixed mold 11 is also provided at the center of the movable mold 12.
Similarly, a center hole 12b penetrating in the thickness direction is provided. In the center hole 12b of the movable mold 12, a first ejector 16 for taking out the formed disk substrate 1 is provided. The first ejector 16 is formed in a cylindrical shape having an outer dimension slightly smaller than the diameter of the center hole 12 b of the movable mold 12. Then, as shown in FIG. 4, the first ejector 16
The movable mold 12 is inserted into the center hole 12b of the movable mold 12 with a gap S2 so as to be movable in a direction parallel to the direction in which the movable mold 12 is moved. In the mold apparatus 10 according to the present invention, the size (clearance) of the gap S2 between the first ejector 16 and the movable mold 12 is 15 to 40 μm.
m. FIG. 4 is an enlarged view of a portion B in FIG.

When the resin material filled in the cavity is solidified and the cavity is opened, the first ejector 16 is moved toward the fixed mold 11 so that the tip of the first ejector 16 is formed. The area (clamping area) on the inner peripheral side of the disk substrate 1 where the information signal is not recorded is pressed, and the disk substrate 1 is removed from the mold apparatus 10.

On the inner peripheral side of the first ejector 16, a punch 17 for punching out the center hole 1a of the disk substrate 1 to be formed is provided. This punch 17
The disk substrate 1 is formed in a cylindrical shape having an outer dimension substantially equal to the diameter of the center hole 1a of the disk substrate 1 and having a center hole 17a at the center. Then, as shown in FIG. 4, the punch 17 is used to move the movable mold 1 similarly to the first ejector 16.
The second ejector 16 is disposed on the inner peripheral side of the first ejector 16 with a gap S3 movably in a direction parallel to the direction in which the second ejector 2 is moved. In the mold apparatus 10 according to the present invention, the size (clearance) of the gap S3 between the punch 17 and the first ejector 16 is set in a range of 15 to 40 μm.

The punch 17 is filled with a molten resin material in the cavity, and is moved toward the fixed mold 11 before the resin material is cured, so that the center hole 1a of the disc substrate 1 is moved. Punch out.

Further, in the center hole 17a of the punch 17,
A second ejector 18 is provided for removing the resin material of the portion corresponding to the center hole 1 a of the disk substrate 1 punched by the punch 17 from the mold device 10. The second ejector 18 is provided with a center hole 17 a of the punch 17.
It is formed in a cylindrical shape having an outer dimension slightly smaller than the diameter of the column. As shown in FIG. 4, the second ejector 18 can be moved in a direction parallel to the direction in which the movable mold 12 is moved, similarly to the first ejector 16 and the punch 17. Is inserted with a gap S4 in the center hole 17a. In the mold apparatus 10 according to the present invention, the size (clearance) of the gap S4 between the second ejector 18 and the punch 17 is 15 to 40 μm.
m.

The second ejector 18 includes a punch 17
When the center hole 1a of the disk substrate 1 is punched out and the resin material filled in the cavity is solidified and the cavity is opened, the tip of the resin material corresponds to the center hole 1a of the disk substrate 1. Is pressed, and the resin material of this portion is taken out of the mold apparatus 10.

In the mold apparatus 10 according to the present invention, as schematically shown in FIG.
A gap S1 between the first mold 16 and the fixed mold 11; a gap S2 between the first ejector 16 and the movable mold 12; a gap S3 between the punch 17 and the first ejector 16; A gap S4 between the ejector 18 and the punch 17 is connected to a vacuum pump (not shown) through a wear powder suction pipe 20, so that the disc substrate 1 is always formed when necessary or when necessary. As appropriate, these gaps S1, S
The inside of S2, S3 and S4 can be evacuated.

When the disk substrate 1 is formed by using the mold apparatus 10 configured as described above, first, the movable mold 12 and the outer peripheral mold 13 are fixed to each other by a fixed mold indicated by an arrow C in FIG. The outer peripheral mold 13 is brought into contact with the fixed mold 11 as shown in FIG. Thus, a cavity 14 is formed between the molding surface 11a of the fixed mold 11 and the molding surface 12a of the movable mold 12.

Next, as shown in FIG. 7, the resin material melted by the resin material melting mechanism of the injection molding machine is connected to the fixed mold 11 and the movable mold 12 through the through hole 15a of the sprue bush 15. Is injected and filled into the cavity 14 between the two.

When the molten resin material is filled in the cavity 14 between the fixed mold 11 and the movable mold 12, before the resin material is cooled, as shown in FIG. The direction shown by arrow D in FIG.
Is moved in a direction approaching the. Thereby, the center hole 1a of the disk substrate 1 is punched and formed.

Next, while applying a predetermined pressure to the resin material in the cavity 14 with the punch 17 being moved to the fixed mold 11 side, the resin material is gradually cooled and hardened. Thereby, the molding surface 11 of the fixed mold 11 is formed.
a and the disk substrate 1 having a surface reflecting the molding surface 12a of the movable mold 12 is formed.

When the resin material in the cavity 14 is cooled and hardened to form the disk substrate 1, as shown in FIG. 9, the movable mold 12 and the outer peripheral mold 13 are moved by arrows E in FIG.
In other words, the moving operation is performed in the direction indicated by, that is, in the direction away from the fixed mold 11. Thus, the cavity 14 is opened.

Next, as shown in FIG. 10, the first ejector 16 and the second ejector 18 are moved in the direction indicated by the arrow F in FIG. As a result, the molded disk substrate 1 is taken out of the mold apparatus 10 and the disk substrate 1
Of the resin material corresponding to the center hole 1a of the mold device 10
Taken out of

In the mold apparatus 10, when punching the center hole 1a of the disk substrate 1, the punch 17
Is moved in the direction approaching the fixed mold 11, pressure is applied to the resin material between the punch 17 and the sprue bush 15 facing the punch 17, and this pressure is applied to the end of the sprue bush 15 on the outer peripheral side. It acts to spread the part toward the fixed mold 11 side. For this reason, when the disk substrate 1 is repeatedly molded using the mold apparatus 10, the outer peripheral end of the sprue bush 15 is deformed in a direction approaching the fixed mold 11 as shown in FIG. May be.

Here, if the size of the gap S1 between the sprue bush 15 and the fixed mold 11 is small, the fixed mold 1
The end on the outer peripheral side of the sprue bush 15 that has been deformed toward the first side comes into contact with the fixed mold 11, and wear powder is generated in the gap S1. The abrasion powder generated in the gap S1 enters the cavity 14 and adheres to the surface of the formed disk substrate 1 to cause a protruding defect on the surface of the disk substrate 1 or to fix the surface. Mold 1
In some cases, the adhesive may adhere to the molding surface 11a of the first substrate 1 or the molding surface 12a of the movable mold 12 and cause a concave defect on the surface of the disk substrate 1.

However, the mold apparatus 10 according to the present invention
As described above, since the size of the gap S1 between the sprue bush 15 and the fixed mold 11 is set to a sufficiently large value of 15 μm or more, the pressure of the resin material accompanying the moving operation of the punch 17 causes , Sprue bush 1
Even when the outer end of the outer mold 5 is deformed in a direction approaching the fixed mold 11, the contact between the deformed end of the sprue bush 15 and the fixed mold 11 is effectively avoided, and the wear is reduced. Generation of powder can be significantly suppressed.

In the mold apparatus 10 according to the present invention, as described above, the gap S1 between the sprue bush 15 and the fixed mold 11 is formed by the vacuum pump (not shown) through the abrasion powder suction pipe 20. Therefore, even if abrasion powder is generated in the gap S1 between the sprue bush 15 and the fixed mold 11, the abrasion powder is appropriately vacuum suctioned, and the abrasion powder is removed. Intrusion into the cavity 14 can be effectively prevented. Note that if the size of the gap S1 between the sprue bush 15 and the fixed mold 11 is small, vacuum suction in the gap S1 may not be performed properly, but in the mold apparatus 10 according to the present invention, Since the size of the gap S1 is set to a sufficiently large value of 15 μm or more, the vacuum suction in the gap S1 by the vacuum pump can be appropriately performed.

When the center hole 1a of the disk substrate 1 is punched in the mold apparatus 10, the punch 17 is moved in the direction approaching the fixed mold 11 as described above. At this time, the punch 17 and the first ejector 1
If the size of the gap S3 between the first and second ejectors 6 is small, the punch 17 and the first ejector 16 come into contact with each other, and wear powder is generated in the gap S3. The wear powder generated in the gap S3 is the same as the wear powder generated in the gap S1.
Disc substrate 1 that has penetrated into cavity 14 and has been formed
Causes a protruding defect on the surface of the disk substrate 1, or adheres to the molding surface 11a of the fixed mold 11 or the molding surface 12a of the movable mold 12,
This may cause a concave defect on the surface of the disk substrate 1.

However, the mold apparatus 10 according to the present invention
As described above, since the size of the gap S3 between the punch 17 and the first ejector 16 is set to a sufficiently large value of 15 μm or more, when the center hole 1a of the disc substrate 1 is punched, Even when the 17 is moved to the fixed mold 11 side, the contact between the punch 17 and the first ejector 16 can be effectively avoided, and the generation of abrasion powder can be greatly suppressed.

In the mold apparatus 10 according to the present invention, as described above, the punch 17 and the first ejector 1
6 is connected to a vacuum pump (not shown) via the abrasion powder suction pipe 20, so that abrasion powder is generated in the gap S3 between the punch 17 and the first ejector 16. Even in this case, the abrasion powder can be appropriately suctioned in a vacuum to effectively prevent the abrasion powder from entering the cavity 14. The punch 17
If the size of the gap S3 between the first ejector 16 and the first ejector 16 is small, vacuum suction in the gap S3 may not be performed properly, but in the mold apparatus 10 according to the present invention, the gap S3 Is set to a sufficiently large value of 15 μm or more, the vacuum suction in the gap S3 by the vacuum pump can be appropriately performed.

When the molded disk substrate 1 and the resin material corresponding to the center hole 1a of the disk substrate 1 are taken out of the die device 10, as described above, The first ejector 16 and the second
Is moved in a direction approaching the fixed mold 11. At this time, if the size of the gap S2 between the first ejector 16 and the movable mold 12 is small, the first ejector 16 and the movable mold 12 come into contact with each other, and wear powder is generated in the gap S2. Will be done. In addition, if the size of the gap S4 between the second ejector 18 and the punch 17 is small, the second ejector 18 and the punch 17 come into contact with each other and generate wear powder in the gap S4. Become. The wear powder generated in the gaps S2 and S4
1 and the abrasion powder generated in the gap S3, enter the cavity 14, adhere to the surface of the molded disk substrate 1, and cause a protruding defect on the surface of the disk substrate 1. Alternatively, it may adhere to the molding surface 11a of the fixed mold 11 or the molding surface 12a of the movable mold 12, and may cause a concave defect on the surface of the disk substrate 1.

However, the mold apparatus 10 according to the present invention
In the above, as described above, the size of the gap S2 between the first ejector 16 and the movable mold 12 and the size of the gap S4 between the second ejector 18 and the punch 17 are each sufficiently 15 μm or more. When ejecting the molded disk substrate 1 and the resin material corresponding to the central hole 1a of the disk substrate 1 from the mold device 10, the first ejector 16 and the second ejector 18 Even when the moving operation is performed in the direction approaching the fixed mold 11, the contact between the first ejector 16 and the movable mold 12 and the contact between the second ejector 18 and the punch 17 are effectively avoided, and the wear is reduced. Generation of powder can be significantly suppressed.

Further, in the mold apparatus 10 according to the present invention, as described above, the gap S2 between the first ejector 16 and the movable mold 12 and the gap S2 between the second ejector 18 and the punch 17 are provided. Since the gaps S4 are respectively connected to vacuum pumps (not shown) via the abrasion powder suction pipes 20, the gaps S2 between the first ejector 16 and the movable mold 12 and the second ejectors 18 Even in the case where abrasion powder is generated in the gap S4 between the punch 17 and the punch 17, the abrasion powder can be appropriately suctioned in vacuum to effectively prevent the abrasion powder from entering the cavity 14. it can.
If the size of the gap S2 between the first ejector 16 and the movable mold 12 or the size of the gap S4 between the second ejector 18 and the punch 17 is small, the size of the gap S2 and the gap S4 is reduced. Although vacuum suction may not be performed properly,
In the mold device 10 according to the present invention, these gaps S2
And the size of the gap S4 is set to a sufficiently large value of 15 μm or more.
The vacuum suction in the inside can be appropriately performed.

In the mold apparatus 10, the gap S1 between the sprue bush 15 and the fixed mold 11,
Gap S between first ejector 16 and movable mold 12
2. The gap S between the punch 17 and the first ejector 16
3. The gap S between the second ejector 18 and the punch 17
If the size of 4 is set too large, when the cavity 14 is filled with a resin material, a large amount of the resin material enters the gaps S1, S2, S3, and S4, and these gaps S1, S2, S3, By curing in S4, large protrusions may be formed on the surface of the molded disk substrate 1.

As described above, the gaps S1, S2, S3, S4
The protrusions formed by the hardening of the resin material that has penetrated are formed in the clamping area on the inner peripheral side of the signal recording area of the disk substrate 1 where the information signal is actually recorded and reproduced. However, if the protrusions are too large, the clamping operation of the disk drive's clamping mechanism will be impeded, and as a result, data recording / reproducing will not be possible. It will have an adverse effect.

In particular, in a hard disk drive or an optical disk drive in which a flying slider flies with a small flying height to record and reproduce signals, a large protrusion is formed in the clamping area of the disk substrate 1 so that appropriate clamping can be performed. Is not performed, a large surface run-out occurs on the magnetic disk or the optical disk due to the clamping failure, so that the flying slider collides with the magnetic disk or the optical disk, thereby causing damage to the magnetic disk or the optical disk. There are cases.

However, the mold apparatus 10 according to the present invention
In the above, as described above, the gap S1 between the sprue bush 15 and the fixed mold 11, the first ejector 1
6 between the movable mold 12 and the movable mold 12, the punch 17 and the first
The gap S3 between the ejector 16 and the gap S4 between the second ejector 18 and the punch 17 has a size of 40 μm.
Since it is set as follows, the molded disk substrate 1
No large protrusions are formed in the clamping area of FIG. Therefore, the disk substrate 1 formed by using the mold apparatus 10 is appropriately clamped by the clamping mechanism of the disk drive, and the recording and reproduction of signals are performed appropriately.

In the mold apparatus 10 according to the present invention, as described above, the inside of the gap S1 between the sprue bush 15 and the fixed mold 11 and the gap between the first ejector 16 and the movable mold 12 are formed. In the gap S2 between the punch 17 and the first ejector 16, in the gap S3 between the punch 17 and the first ejector 16,
Since the generation of abrasion powder in the gap S4 between the punch 8 and the punch 17 is greatly suppressed, these gaps S1, S2,
Inconveniences such as wear powder accumulating in S3 and S4 and hindering normal operation of each member can be effectively prevented, and maintenance can be simplified.

[0059]

EXAMPLES In order to confirm the effects of the present invention, the following experiments were conducted. That is, using the mold apparatus 10 described above,
Gap S1 between sprue bush 15 and fixed mold 11
And the size of a gap S2 between the first ejector 16 and the movable mold 12, a gap S3 between the punch 17 and the first ejector 16, and a gap S4 between the second ejector 18 and the punch 17. The disk substrate is actually formed while changing the size of the disk substrate. The height of the protrusion formed in the ping region and the relationship with the clamping failure caused by the protrusion were examined.

Here, the gaps S1, S2, S3
The sizes of S4 are all the same, and the gaps S1, S
2, S3, and S4 were not varied.
In addition, the generation of abrasion powder indicates a case where no generation of abrasion powder that causes a defect on the disk substrate is observed.
In the case where abrasion powder causing defects on the disk substrate was generated, the evaluation was evaluated as x. The state of clamping was evaluated as ○ when no clamping failure occurred, and evaluated as × when clamping failure occurred. Table 1 shows the results of the experiment.

[0061]

[Table 1]

From the results shown in Table 1, when the disk substrates were molded with the sizes of the gaps S1, S2, S3, and S4 set to 15 μm or more as in Examples 1 to 4 and Comparative Example 3, It was found that in S1, S2, S3, and S4, abrasion powder that could cause defects in the disk substrate could be generated.

On the other hand, when the sizes of the gaps S1, S2, S3, and S4 are less than 15 μm as in Comparative Examples 1 and 2, wear powder is generated in the gaps S1, S2, S3, and S4. However, it has been found that a defect occurs in the formed disk substrate due to the abrasion powder.

Also, from the results shown in Table 1, Examples 1 to
4 and Comparative Examples 1 and 2, gaps S1, S2, S3
When the disk substrate is molded with the size of S4 set to 40 μm or less, the height of the projections formed in the clamping area of the molded disk substrate can be suppressed to 50 μm or less, which causes clamping failure. It has been found that the clamping operation can be performed properly without any problem.

On the other hand, as in Comparative Example 3, the gap S
When the size of 1, S2, S3, and S4 exceeds 40 μm, a large protrusion having a height of more than 50 μm is formed in the clamping area of the molded disk substrate, and an appropriate clamping operation is performed by the large protrusion. It was found that it was hindered and a clamping failure occurred.

As can be seen from the above results, the mold apparatus 10 according to the present invention includes the sprue bush 15 and the fixed mold 1
1, a gap S2 between the first ejector 16 and the movable mold 12, a gap S3 between the punch 17 and the first ejector 16, a gap S3 between the second ejector 18 and the punch 17, The size of the gap S4 between 15 and 4
By setting the distance in the range of 0 μm, the gap S
1, S2, S3, and S4 are effectively prevented from generating wear powder, so that a disk substrate having no defect can be formed, and a large projection is formed in a clamping area of the formed disk substrate. Effectively prevent
A disk substrate on which a clamping operation can be appropriately performed can be formed.

[0067]

According to the mold apparatus of the present invention, the size of the gap between the moving member which is moved to the fixed mold side and the member adjacent to this member is set in the range of 15 to 40 μm. Therefore, the generation of abrasion powder accompanying the moving operation of the moving member can be significantly suppressed, and the abrasion powder can be prevented from entering a closed space formed between the fixed mold and the movable mold. hand,
A good disk substrate having no defects on the surface can be formed, and inconveniences such as formation of large projections on the disk substrate to be formed that hinder the clamping operation can be effectively avoided.

Further, since the mold apparatus according to the present invention is provided with the vacuum suction means for vacuum-suctioning the gap between the moving member and the member adjacent thereto, it is assumed that the moving member is adjacent to the moving member. Even if abrasion powder is generated in the gap between the member and the member, the abrasion powder is appropriately vacuum suctioned, and the amount of abrasion is formed between the fixed mold and the movable mold. Intrusion into the inside can be reliably prevented.

Further, according to the mold apparatus of the present invention, since the generation of wear powder in the gap between the moving member and the member adjacent thereto is largely suppressed, the wear powder is formed in the gap. Can be effectively prevented from accumulating and hindering the normal moving operation of the moving member,
Maintenance can be simplified.

[Brief description of the drawings]

FIG. 1 is a perspective view of a disk substrate.

FIG. 2 is a sectional view showing an example of a mold apparatus according to the present invention.

FIG. 3 is an enlarged cross-sectional view showing a portion A in FIG. 2;

FIG. 4 is an enlarged sectional view showing a portion B in FIG. 2;

FIG. 5 is a view schematically showing a state in which a pipe for suctioning abrasion powder is connected to gaps between members constituting the mold apparatus.

FIG. 6 is a cross-sectional view of the mold apparatus showing a state in which a cavity is formed between a fixed mold and a movable mold.

FIG. 7 is a cross-sectional view of the mold apparatus showing a state in which the resin material melted by heating is filled in the cavity.

FIG. 8 is a cross-sectional view of the mold apparatus showing a state in which a center hole of a disk substrate is formed by punching.

FIG. 9 is a cross-sectional view of the mold apparatus showing a state where the cavity is opened.

FIG. 10 is a cross-sectional view of the mold apparatus showing a state in which a resin material in a portion corresponding to a center hole of the disk substrate and the disk substrate is taken out.

FIG. 11 is an enlarged cross-sectional view of a main part of the mold apparatus, showing a state in which an outer peripheral end of a sprue bush is deformed.

FIG. 12 is a sectional view showing a conventional mold apparatus.

[Explanation of symbols]

1 disk substrate, 10 mold device, 11 fixed mold,
12 movable mold, 13 outer peripheral mold, 14 cavity, 1
5 sprue bush, 16 first ejector, 17
Punch, 18 second ejector, 20 pipe for suction of wear powder, S1, S2, S3, S4 gap

Claims (5)

[Claims] 1. A mold apparatus for molding a disk substrate by cooling and curing a molten resin material filled in a closed space formed between a fixed mold and a movable mold in the closed space. A moving member provided movably with respect to the movable mold, wherein a size of a gap between the moving member and a member adjacent thereto is in a range of 15 to 40 μm; A mold apparatus comprising vacuum suction means for vacuum-suctioning a gap between a moving member and a member adjacent thereto. 2. The mold apparatus according to claim 1, wherein said moving member is a punch for punching a center hole of said disk substrate. 3. The mold apparatus according to claim 1, wherein the moving member is a first ejector for removing the formed disk substrate from the mold apparatus. 4. The moving member according to claim 2, wherein the moving member is a second ejector for removing a portion of the resin material punched by the punch from the mold device.
The described mold apparatus. 5. A punch receiving member which is provided at a central portion of the fixed die and faces a tip portion of the punch, wherein a size of a gap between the punch receiving member and the fixed die is 15 to 15. 3. The mold apparatus according to claim 2, further comprising a vacuum suction unit which is within a range of 40 [mu] m and vacuum-evacuates a gap between the punch receiving member and the fixed mold.