JPH0671749B2 - Disc peeling method in disc molding - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the molding of disks as disk-shaped recording media such as video disks and audio disks, and more particularly to a method of peeling a disk from a mold plate after mold opening.

[0002]

2. Description of the Related Art Conventionally, in this type of disk molding, a cavity forming portion of a fixed side mold plate and a movable side mold plate of a mold is formed as a mirror surface portion, and a pit pattern as an information track surface is formed on one mirror surface portion. A stamper, which is a base material for transferring, is held.

The stamper is configured to be held by a ring-shaped outer peripheral pressing member which seals the outer peripheral region of the cavity and also serves as a spacer between the mold plates, and an inner peripheral pressing member. The member is attached to a template that holds the stamper. With the above configuration, the cavity is filled with the molten resin to form a disk.

The separation of the disk, that is, the separation from the template, is performed by supplying air to the contact surface between the mirror surface portion of the template on which the stamper is not held and the disk to bring the disk into close contact with the stamper and then mechanically opening the mold. A method of ejecting a disc with an ejection mechanism or an air blow structure is adopted.

[0005]

By the way, in the cavity, one surface of the disk is in contact with the stamper and the other surface is in contact with the mirror surface portion of the template having no stamper. There is a general understanding that the disc adheres to the stamper side when the mold clamping force is lowered at the time of mold opening, but it is not clear to which part the disc does not have the stamper as described above. The adhesion of the plate to the mirror surface is cut off with air and completely adhered to the stamper side.

However, as a result of experiments and research by the present inventor, it was found that the disk adheres to the mirror surface portion of the template, which originally has no stamper, due to its strong adhesion. Therefore, conventionally, the disc has been purposely peeled off from the mirror surface portion to be originally attached and attached to the stamper side, which causes a problem with respect to product accuracy.

In other words, it has been confirmed that the outer peripheral side separates from the stamper when the mold clamping force is lowered. However, in the conventional method, the separated one is fitted again, so that it is accurately fitted in the same pit. This is not always the case, and so-called doubling occurred due to pit displacement.

Further, as shown in FIG. 6, the outer peripheral surface 80a of the disk 80 has an outer peripheral pressing member 8 having a depth in the peeling direction.
Since it is in contact with No. 2, it is difficult to pull out, and if it is slightly displaced, it is curved and deformed into a bowl shape or a propeller shape as shown by the chain double-dashed line, impairing the precision of the molded product. Particularly, in the case of a high-precision disc such as a computer disc, the disc temperature at the time of peeling is high (for example, about 120 ° C. in the case of polycarbonate resin), there is a risk that the degree of deformation becomes large. In the figure, reference numeral 84 indicates a mirror surface portion, and reference numeral S
Indicates a stamper.

Further, in the conventional ejecting method, the disk is liable to be deformed into a bowl shape irrespective of the mechanical form or the pneumatic form by air blow. Therefore, the inner peripheral side is gently protruded by mechanical means and the outer peripheral side is formed. Although there have been devised methods such as applying air pressure to the above to prevent distortion as a whole, a satisfactory peeling accuracy has not been achieved yet. On the other hand, the complicated structure due to the presence of the mechanical protrusion mechanism is also a problem.

Therefore, according to the present invention, it is possible to avoid a decrease in precision such as doubling and easily perform peeling without the need for a mechanical projection mechanism. Therefore, it is possible to improve the molding precision and the working efficiency of the disc. The purpose is to provide a peeling method.

[0011]

The present invention was devised in order to achieve the above-mentioned object, and its characteristic feature is that when the mold clamping force is lowered, the mirror surface portion of the other mold plate having no stamper and the disk are brought into close contact with each other. The degree is increased by air suction, and after the disc and the stamper are separated as the mold is opened, air is supplied to the contact surface of the disc to separate the disc from the mirror surface portion of the template.

Further, according to the present invention, the step of pressing the disk with air from the stamper side in association with the suction of air can be performed.

[0013]

According to the present invention, when the mold clamping force is lowered, the disk strongly adheres to the mirror surface portion to which it originally adheres due to the air suction,
It separates from the stamper side as the mold opens. Since the disc is in close contact with the mold plate that does not have the outer peripheral pressing member, there is no one that restrains the outer peripheral portion when the mold is open, and air is supplied to the close contact surface of the disc in such a state. The air supply cuts the disc from the close contact with the mirror surface portion, and the disc is automatically separated without the need for external pressure such as a protruding mechanism.

Further, according to the present invention, the disk is pressed by the air from the stamper side in accordance with the suction of air, so that the disk can be surely and easily adhered to the mirror surface portion that should be originally adhered.

[0015]

1 to 5 show an embodiment of the present invention.
The mold 2 is provided with a fixed-side mold plate 4 and a movable-side mold plate 6, so that the mold 2 is directly supported and opened / closed by two guide rods 8 which also have a tie bar function without using a die plate. It has become. As the guide rod 8, for example, a rod of a mold clamping cylinder (not shown) can be directly used, and the fixed side mold plate 4 can be held by the bearing member 10 so as to be smoothly slidable. The nozzle 12 is inserted into the nozzle guide hole 4a formed in the fixed-side template 4 for injection.

The sprue bush 1 is provided at the center of the fixed-side template 4.
4 is attached, and the cavity 13 is provided on the mold facing surface.
The fixed-side mirror surface portion 16 which is one of the components of (1) is fitted into the sprue bushing 14 and the outer peripheral portion is fixedly attached by a bolt 17. A stamper S as a transfer base material is attached to the fixed-side mirror surface portion 16, and the stamper S is held by an inner peripheral pressing member 15 and an outer peripheral pressing member 18.

The outer peripheral pressing member 18 is composed of a ring member 20 which doubles as a spacer between the molds and seals the outer peripheral region of the cavity 13, and a stamper holding portion 22 which is integrally formed on the inner peripheral surface of the ring member 20. ing. Also,
Threaded holes 20a are formed on both sides of the ring member 20, and the fixed-side mold plate 4 and the movable-side mold plate 4 and the movable-side mold plate 4 do not need to be held manually by a through bolt 24 penetrating the fixed-side mold plate 4 or the movable-side mold plate 6. Any of the template 6 can be attached and converted.

As a result, it is possible to reduce the labor required for exchanging the stamper and to easily and smoothly perform the exchanging work. That is, in the conventional structure, since it is configured to be attached to and detached from only one of the template plates, it is necessary to hold the outer peripheral pressing member 18 which is a heavy object during the replacement of the stamper, but it is possible to move it by replacing the through bolt 24. It can be temporarily temporarily fixed to the side mold plate 6 side, and can be reattached to the fixed side mold plate 4 side without requiring a holding operation by replacing the through bolt 24 again and tightening it in the mold closed state. . Reference numerals 4b and 6a denote through bolts 2.
4 shows the insertion hole.

On the other hand, a gate cut member 26 is attached to the central portion of the movable side mold plate 6, and a movable side mirror surface portion 28 which is the other component of the cavity 13 is attached to the mold facing surface. The gate cut member 26 is composed of a cylinder member 30 fixed to the movable side mold plate 6, and a cut pin 34 having a sprue ejector pin 32 and capable of advancing and retracting in the cylinder member 30. The movable side mirror surface portion 28 is fitted in the cylinder member 30, and the outer peripheral portion is fixed by bolts 29.

Next, the holding operation of the stamper S will be described. First, the stamper S is applied to the fixed-side mirror surface portion 16, the inner peripheral side pressing member 15 presses the inner peripheral side, the outer peripheral pressing member 18 holds the outer peripheral side, and air is sucked from the air suction port 16a. By this air suction, a vacuum state is created between the stamper S and the fixed mirror surface portion 16, and the stamper S is brought into close contact with the fixed mirror surface portion 16 without unevenness.

Even if the stamper S does not have perfect flatness, it is forcibly brought into close contact by air suction, so that the heat conductivity between the stamper S and the fixed-side mirror surface portion 16 becomes uniform, and the temperature unevenness occurs. It is possible to prevent the deterioration of the molding accuracy due to.

Further, since the outer peripheral side of the stamper S is held in a non-contact state with the clearance C that does not pass the resin between the stamper S and the stamper holding portion 22, the radial expansion of the stamper S due to the resin heat is allowed, A decrease in molding accuracy due to expansion inhibition is prevented.

Next, the disc peeling structure and its process will be described with reference to FIGS. Gate cut member 2
6, an air supply passage 38 is formed in the cylinder member 30, and the cylinder member 30 and the movable side mirror surface portion 28 are formed.
An annular air discharge port 40 communicating with the air supply path 38 is formed between and. Also, as shown in FIG.
An annular air discharge port 42 is formed between the sprue bush 14 and the inner peripheral pressing member 15.

When the cavity 13 is filled with resin and the gate cut is completed and the mold is opened after cooling and solidification, air is sucked from the air discharge port 40 of the movable mirror surface portion 28 as the mold clamping force drops. To be done. This makes disk 4
4 further strongly adheres to the movable mirror surface portion 28 which originally adheres, and when the mold is opened, it separates from the stamper S and remains on the movable mirror surface portion 28 as shown in FIG. In this example, the air is ejected from the fixed-side air ejection port 42 at the same time as the air is ejected from the air ejection port 40 to press the disk 44 against the movable-side mirror surface portion 28. The disc 44 and the stamper S can be smoothly attached to each other and separated from each other when the mold is opened. Reference numeral 44a indicates a central hole of the disc 44.

When the air suction from the air discharge port 40 is released and the air is discharged in the opposite way, as shown in FIG. 5, the disk 44 is momentarily separated from the movable side mirror surface portion 28 and can be taken out. It will be in a state.

As described above, the disc 44 can be easily peeled by bringing the disc 44 into close contact with the movable mirror surface portion 28, which is originally in close contact, and supplying air to the contact surface with the mold opened. be able to. The problem of doubling does not occur because it is not re-fitted once separated as in the conventional case, and the problem of deformation due to contact of the outer peripheral surface is avoided because the outer peripheral pressing member 18 of the stamper S does not exist on the movable side mold plate 6. To be done. In addition, since the peeling is performed by the air supply method that does not use the protruding mechanism, the disk 4
4 can be improved in flatness, and the configuration can be simplified.

[0027]

According to the present invention, since the disc is brought into close contact with the mirror surface portion which is originally in close contact with the stamper and separated from the stamper by the mold opening, and after the separation, air is supplied to the adhered surface to separate the disc. It is possible to avoid a decrease in accuracy due to so-called doubling that causes an error in combination, and it is possible to avoid curved deformation due to abutment of the outer peripheral surface, and it is possible to improve accuracy by improving the flatness of the disk. Further, since the projecting structure is not required, it is possible to avoid the bending deformation due to the projecting and to simplify the structure.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a disc peeling method in disc molding according to the present invention.

FIG. 2 is an enlarged cross-sectional view showing a holding state of the outer peripheral portion of the stamper.

FIG. 3 is a sectional view of a main part of a fixed-side template.

FIG. 4 is a cross-sectional view showing a state in which a disk is in close contact with a movable mirror surface portion.

FIG. 5 is a cross-sectional view showing a state in which the disk is peeled from the movable side mirror surface portion by air supply.

FIG. 6 is a schematic cross-sectional view showing a conventional bending deformation at the time of peeling.

[Explanation of symbols]

 2 Mold 4 Fixed-side mold plate 6 Movable-side mold plate 13 Cavity 16 Fixed-side mirror surface part (one mirror surface part) 15 Inner peripheral pressing member 18 Outer peripheral pressing member 28 Movable mirror surface part (other mirror surface part) 44 Disk S Stamper

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B29L 17:00 4F

Claims (2)

[Claims] 1. A mirror surface portion of one of a fixed-side mold plate and a movable-side mold plate of a mold forming a disk-shaped cavity,
In a method of forming a disk by holding a stamper with a ring-shaped outer peripheral pressing member and an inner peripheral pressing member that are attached to a template having the mirror surface portion, and filling a cavity with molten resin to form a disk, The degree of adhesion between the disc and the mirror surface of the template is increased by air suction, and after the disc and the stamper are separated as the mold is opened, air is supplied to the contact surface of the disc and the disc is transferred from the mirror of the other template. A method for peeling a disc in disc molding for peeling. 2. The method for peeling a disk in disk molding according to claim 1, wherein the disk is pressed from the stamper side with air in accordance with air suction.