JP3160837B2 - Disk molding die and molding method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for molding a disk and a method of molding the same, and more particularly to a mold of an optical recording medium disk such as a video disk and a compact disk and a method of molding the same. .

[0002]

2. Description of the Related Art Generally, a disk molding die is provided with a stamper disposed on a mirror surface of one of a fixed die and a movable die, and a movable die is brought into contact with the fixed die to form a stamper and the other die. Are formed so as to form a cavity by the mirror surface. A disk is formed by injection-filling a molding material heated and melted from substantially the center of the cavity and solidifying it by cooling.

As a conventional disk forming die, for example, as shown in FIG. 4, when a stamper 7 is arranged on a mirror surface of a movable die 2, a gap between the mirror surface of the fixed die 1 and the formed disk is formed. Air supply passage 16 for blowing air to
And a movable-side first air supply passage 41 for blowing air between the stamper 7 of the movable mold 2 and the formed disk so as to open near the center of the disk. I have. In this disk molding die, the fixed side air supply passage 16 and the movable side first air supply passage 4
1, the air blown between the mirror surface of the fixed mold 1 and the molded disk and between the stamper 7 of the movable mold 2 and the molded disk passes through the molded disk. From the mirror surface of the fixed mold 1 and the stamper 7 of the movable mold 2. The separated disk is ejected by the ejector 27.

As another conventional disk molding die, as disclosed in Japanese Patent Application Laid-Open No. 1-200924, an air supply port is provided in the vicinity of an outer peripheral holding ring of a stamper, and the air supply port is provided in the air supply port. There is also known one provided with a communication passage communicating therewith. In this disk molding die, the movable disk is separated from the stamper of the molded disk from both the center and the outer periphery.

Incidentally, when injection molding and filling the molding material melted by heating, a monomer gas or the like (hereinafter referred to as gas) is generated. This gas enters the space of the outer circumferential holding ring where the outer circumferential edge of the stamper of the movable mold is located through a slight gap between the stamper and the outer circumferential holding ring, and stays there. When it is pulled by the molded product and separated from the mirror surface of the movable mold, it penetrates between the mirror surface and the stamper and corrodes the stamper. When the corrosion of the stamper is transferred, the quality of the disc is degraded.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 63-82714, a gas suction space extending all around the outer periphery of a stamper and a gas suction space for connecting the gas suction space to suction means. There has been known an apparatus in which a communication path is provided to suck gas that has entered between a mirror surface and a stamper.

Further, as disclosed in Japanese Utility Model Publication No. Hei 7-42682 (hereinafter, reference numerals are referred to those in FIG. 4), a fixed air supply passage 1 provided on a fixed mold side.
6, a movable first air supply passage 41 provided in the movable mold 2 so as to open to the center of the cavity 7, and a movable side opening to a space 25a formed in the outer circumferential holding ring 25 of the stamper 7. An annular vacuum groove 44, which communicates with the second air supply passage 42 and the air suction passage 43 and opens on the back surface of the outer peripheral edge of the stamper 7, comprises a movable second air supply passage 42, a vacuum groove 44, and the like. Are known. In this device, the outer peripheral edge of the stamper 7 is prevented from rising irregularly from the mirror surface by making the movable-side second air supply passage and the vacuum groove 44 face each other, and the fixed-side air supply passage 16 and the movable-side First
The air is blown from the center of the disk toward the outer circumference by the air supply passage 41 and the air blows from the outer circumference of the disk toward the center by the movable second air supply path 42, so that the disk is evenly distributed from the stamper 7. In addition, they are instantaneously peeled off. As shown in FIG. 5, the movable-side second air supply passage 42 includes a switching valve 60 and a pressure adjustment valve 61 that adjusts the supply of air at a pressure necessary for releasing the formed disk from the air supply. Source 53
It is interposed between.

[0008]

However, in the prior art disclosed in Japanese Utility Model Publication No. 7-42682, the switching valve 60 is connected to the air supply source 53 as shown in FIG. Is not supplied to the movable-side second air supply passage 42, the movable-side second air supply passage is open to the atmosphere. Therefore, the gas generated when the molding material is injected and filled into the cavity 3 is supplied to the gaps 26 a and 26 between the fixed mold 1 and the outer peripheral holding ring 25.
6b and the space 25a in the outer peripheral holding ring 25, and is cooled to be liquefied, or subsequently dried and solidified, and the liquefied or solidified gas G is accumulated in the space 25a. The Rukoto. The liquefied or solidified gas is mixed with the air when the air is blown out from the movable-side second movable-side air supply passage 42 at the time of release from the mold, and is formed into the mirror surface of the stamper 7 or the movable mold 2 or formed. There has been a problem that it adheres to the disc and causes molding failure of the disc.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and it is intended to prevent the gas generated when a hot-melted molding material is injected and filled into a cavity from accumulating in a space or the like of an outer peripheral holding ring. An object of the present invention is to provide a disk molding die and a molding method thereof, which can prevent the occurrence of defective molding of the disk and thereby improve the production efficiency.

[0010]

In order to achieve the above object, the invention relating to a disk forming die according to the present invention comprises a fixed die and a movable die having a cavity formed in an abutment surface, and a fixed or movable die. A stamper disposed on one of the mirror surfaces, a stamper outer peripheral holding member that holds the outer periphery of the stamper with a slight gap, an air supply passage that opens into a space formed in the stamper outer peripheral pressing member, In a disk forming mold having an air supply source for supplying air to the air supply passage, a release blow pressure for supplying air from the air supply source to the air supply passage at a pressure required for releasing the molded disk. An adjusting means and a pressure adjusting means for preventing gas stagnation to be supplied to the air supply passage at a pressure lower than the release air pressure are switchably provided.

According to a second aspect of the present invention, there is provided a disk forming die according to the first aspect, wherein a cavity is provided between the stamper outer peripheral pressing member and the other die. A small gap communicating with the mold is provided, and a passage communicating the gap with the outside of the mold is provided.

According to a third aspect of the present invention, in order to achieve the above object, a mold closing step of bringing a movable mold into close proximity abutment with a fixed mold, and the two abutted molds are provided. A mold clamping step of increasing the pressure of the mold, an injection step of injecting and filling a molding material heated and melted into a cavity formed on the abutting surface of both molds, a cooling step of cooling and solidifying the molding material, and a fixed mold. And a mold opening step of sequentially separating the movable mold from the mold.When the molded disc is released, the air supply passage opening into the space formed in the stamper outer peripheral pressing member is used to release the disc from the air supply passage. When performing high-pressure air blowing having the pressure required for mold release, and further, when injection-filling the hot-melted molding material into the cavity,
The present invention is characterized in that air is blown out from the air supply passage at a pressure necessary and sufficient to prevent gas from entering the space in the stamper outer peripheral holding member.

According to the structure of the first aspect, the movable mold is brought into close contact with the fixed mold to form a cavity, the pressure is increased, the mold is clamped, and the molding material melted by heating is injected and filled into the cavity. The molding material is cooled and solidified to form a disk.
At least, when the cavity is injected and filled with the heated and melted molding material, air from an air supply source is supplied to the space in the stamper outer peripheral holding member by the gas mixing preventing pressure adjusting means, and the generated gas is filled in the space. To prevent intrusion and stagnation. When the molded disc is released from the mold, by switching to the release blowing pressure adjusting means, air having the pressure necessary to peel the molded disc from the stamper from the air supply source is passed through the air supply passage. To feed the outer periphery between the stamper and the molded disc,
Separate the disk from the stamper.

According to the second aspect of the present invention, the gas for injection-filling the molding material heated and melted into the cavity is supplied through the pressure adjusting means for controlling the injection pressure of the molding material and the gas retention prevention. Instead of relying on flowing out of the parting line due to the low pressure from the supply source, it easily flows out of the mold through the cavity, the space formed between the fixed mold and the stamper outer peripheral pressing member, and the passage.

According to the third aspect of the present invention, low-pressure air is blown out at least at the time of injecting and filling the molding material heated and melted into the cavity, so that the injection of the molding material is not affected and the outer periphery of the stamper is held down. The disk can be formed without retaining gas in the space in the member. When the molded disk is released after cooling is completed, high-pressure air is blown from an air supply passage that opens into a space formed in the stamper outer peripheral pressing member, and the molded disk is peeled from the stamper.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an embodiment of a disk forming die according to the present invention will be described in detail with reference to FIGS. The same reference numerals in the drawings denote the same or corresponding parts.

The disk molding die comprises a fixed die 1 and a movable die 2 which are arranged opposite to each other. The fixed mold 1 and the movable mold 2 are respectively attached to a fixed plate 5 and a movable plate (not shown) of the mold clamping device, and the movable mold 2 is moved relative to the fixed mold 1 by driving the mold clamping device. Proximity
The mold is closed, clamped and opened by moving away from each other, and the cavity 3 is formed on the abutment surface between the fixed mold 1 and the movable mold 2.
Is formed. A stamper 7 is disposed on one of the mirror surfaces of the fixed mold 1 and the movable mold 2, and transfers information to a disk to be molded. In this embodiment, the case where the stamper 7 is arranged on the mirror surface of the movable mold 2 will be described. However, the present invention is not limited to this, and the stamper 7 may be arranged on the mirror surface of the fixed mold 1. it can.

The fixed mold 1 has a mirror block 10 having a through hole 11 formed substantially at the center thereof, and a mess cutter 12 carried in the through hole 11.
A sprue bush 13 is carried therein. The outer peripheral surface of the mirror block 10 is formed in a tapered shape so as to be inclined with respect to the mirror surface. The cavity-side end surface of the messutter 12 is formed so as to be continuous with the mirror surface of the mirror block 10 and form the same plane. An opening 14 having a tapered portion is formed in the fixed platen 5, and the nozzle 15 of the injection device is disposed so as to be able to approach and retreat so as to contact the sprue bush 13 through the opening 14.

The fixed mold 1 has a fixed air supply passage 16.
Are formed. The fixed side air supply passage 16 passes through the mess cutter 12 and the mess cutter 12 and the mirror block 10.
Is formed so as to open into the cavity 3 between the through holes 11.

The movable mold 2 is provided with a mirror block 20, a through hole 21 is formed substantially at the center thereof, and a fixed sleeve 22 is provided in the through hole 21. Then, the stamper 7 is arranged on the mirror surface of the mirror block 20. The stamper holder 2 is provided outside the fixed sleeve 22.
The outer peripheral holding ring 25 is attached to the outer periphery of the mirror block 20. The inner peripheral surface of the outer peripheral holding ring 25 is tapered so as to be aligned with the outer peripheral surface of the mirror block 10 of the fixed mold 1 and, when the mold is brought into contact with the outer peripheral surface of the mirror block 10. In order to allow the gas to pass therethrough without passing through the molding material, a small gap 26a of, for example, about 5 to 30 μm is formed. In addition, the outer peripheral holding ring 25
The fixed mold side end face of the fixed mold 1
Are formed so as to have a gap 26b continuous with the gap 26a. The inner peripheral edge of the stamper 7 is held by the tip claw portion of the stamper holder 24, and the outer peripheral edge is allowed to pass air without passing the molding material by the outer peripheral pressing ring 25, for example, a minute interval of about 5 to 30 μm. Is held.

A sleeve-like ejector 27 is slidably inserted through the fixed sleeve 22, and a male cutter 28 is slidably inserted through the ejector 27. An ejector plate 27a is provided at a rear end of the ejector 27, and a cutter plate 28a is provided at a rear end of the male cutter 28.

A guide space 2 is provided in a component of the movable mold 2.
9 are formed, and an ejector plate 27a is arranged in the guide space 29. Ejector plate 27
a is a spring 3 between the front surface thereof and the front wall of the guide space 29.
By interposing 0, it is urged to retreat, and an ejector pin 31 is in contact with the back surface. Similarly to the ejector plate 27a, the cutter plate 28a is also disposed in the guide space 29, and is urged to retreat by a spring 32 interposed between the front surface thereof and the front wall of the guide space 29, so that the cutter protrudes. Pin 3
3 is in contact. The ejector pin 31 and the cutter protruding pin 33 are driven by a control unit and an ejector driving unit or a cutter driving unit (not shown), respectively.

In this embodiment, the fixed mold 1 has
A passage 40 communicating the gap 26b with the outside of the mold is formed. An air supply means can be connected to the passage 40. When the passage 40 is not formed, gas is discharged from the parting line of the fixed mold 1 and the movable mold 2 by the injection pressure of the molding material. Can be done. In the movable mold 2, a movable first air supply passage 41 and a movable second air supply passage 42 are formed, and an air suction passage 43 is formed. The movable-side first air passage 41 is
It is formed so as to pass through the fixed sleeve 22 and open into the cavity 3 over the entire circumference between the fixed sleeve 22 and the stamper holder 24. Movable second air passage 42
Is annularly opened toward the outer peripheral edge of the stamper 7 through the inside of the stamper outer peripheral holding ring 25. Further, the air suction passage 43 is opened in an annular shape along the outer peripheral edge of the stamper 7 through the mirror block 20.

As shown in FIG. 2, the movable second air passage 4
2 is connected to a switching valve 50, and the switching valve 50 includes a pressure regulating valve 51 as release air pressure regulating means arranged in parallel.
And a pressure adjusting valve 5 as a pressure adjusting means for preventing gas stagnation.
2 and connected to the air supply source 53. As shown by symbols in FIG. 2, the pressure regulating valves 51 and 52 are composed of throttle valves, and control the pressure by limiting the flow rate of air. The pressure adjusting valve 51 is set at a pressure necessary for peeling the formed disk from the stamper 7.
Further, the pressure regulating valve 52 allows the gas generated when the molding material is injected and filled into the cavity to flow out of the gap 26a to the passage 40 through the gap 26b without entering the space in the outer peripheral holding ring. The pressure is set lower than the pressure regulating valve 51 so as not to affect the injection of the molding material into the cavity.

Next, a method of forming a disk according to the present invention using the disk forming die configured as described above will be described with reference to FIG. FIG. 3 shows a time chart of the disk forming method according to the present invention, and is configured to sequentially perform steps of mold closing, pressure increasing, injection, cooling, mold opening, and ejection in order. .

From the intermediate time when the mold is open (FIG. 3A), the movable mold 2 is brought close to the fixed mold 1 at high speed by driving the mold clamping device (FIG. 3B). When it is detected that it has approached the fixed mold 1 to a predetermined position, the approach driving speed of the mold clamping device is switched to low speed, and low-speed mold closing is performed (FIG. 3C). Simultaneously with the start of the high-speed mold closing, the nozzle 15 of the injection device is advanced and brought into contact with the sprue bush 13 at high pressure.

When it is detected that the movable mold 2 has collided with the fixed mold 1, the pressure is increased to perform mold clamping (d in FIG. 3). When it is detected that the mold clamping pressure has reached a predetermined pressure by the pressure increase, the molding material heated and melted is injected into the cavity 3 (FIG. 3).
E) When the injection is completed, the molding material injected into the cavity 3 is cooled and solidified (FIG. 3). When the injection (FIG. 3E) is completed, the injection device starts measuring the molding material for the next cycle after a predetermined time has elapsed (not shown). Further, a gate cut delay is performed at the time of injection of the molding material (FIG. 3E), and at the time of cooling (FIG. 3F), the male cutter 28 advances to perform the gate cut. In addition,
The pressure increase during mold clamping can be changed stepwise during injection (FIG. 3E) and during cooling (FIG. 3F).

When the molding material is cooled and solidified by cooling for a predetermined time, the pressurizing pressure of the mold clamping device is released (FIG. 3G), and the movable mold 2 is separated from the fixed mold 1 at a low speed by driving the mold clamping device. (Fig. 3H). When it is detected that the movable mold 2 is separated from the fixed mold 1 to a predetermined position, the separation driving speed of the mold clamping device is switched to high speed to perform high-speed mold opening (FIG. 3).
(3) When the opening of the mold by a predetermined amount is detected, the separation driving of the movable mold 2 is switched to a low speed (N in FIG. 3). At the same time as the separation driving of the movable mold 2 is stopped, the ejector 27 is advanced (FIG. 3L) to protrude the formed disk, the ejector 27 is retracted (FIG. 3A), and at the time of cooling (FIG. 3F). Oscutter 2 advanced to cut gate
8 is retracted, and one cycle is completed.

At the time when the injection is completed, a fixed-side air blowing delay for causing the fixed-side air blowing to blow out air from the fixed-side air supply passage 16 at a predetermined timing, and a movable-side first air supply passage 41. A movable-side first air blowing delay for causing the movable-side first air blowing to blow out air at a predetermined timing, and a movable-side second air blowing high-pressure air from the movable-side second air supply passage. Movable second air blowing delay for performing blowing at a predetermined timing is performed by a timer or the like. In the embodiment shown in FIG. 3, the fixed-side air blowing is performed at the time of cooling (FIG. 3) due to the fixed-side air blowing delay. The movable-side first air blowing is performed from when the movable mold is opened at a high speed (FIG. 3) to when the ejector advances (FIG. 3L).

A gas generated when the molding material is injected and filled into the cavity 3 is supplied to the movable-side second air supply passage 42.
The switching valve 50 constantly supplies air at a low pressure by the switching valve 50 so that air can flow out from the gap 26a through the gap 26b into the passage without entering the space 25a in the stamper outer circumferential holding ring 25. Space 25
a. The optimum value of the air pressure is set by actually performing molding and finding a maximum pressure at which microbubbles are not generated by the air from the stamper holding ring 25 on the outer periphery of the molded disk. When the switching valve 50 is switched by the completion of the outer high-pressure air blowing delay, air having a pressure necessary to peel the formed disk from the stamper 7 is supplied from the air supply source 53 via the pressure adjusting valve 51. The air is blown out to the space 25 a in the outer peripheral stamper holding ring 25. Note that, in the embodiment shown in FIG. 3, the timing of the outer peripheral high pressure air blowing is from when the movable mold is opened at a low speed (FIG. 3h) to when the high speed mold is opened (FIG. 3) after cooling is completed. Although the description has been made with respect to the case up to this point, the present invention is not limited to this, and may be performed from the time of cooling in order to prevent mold release unevenness depending on the stamper used. Although not shown in FIG. 3, it is desirable that the air suction passage 43 always sucks the stamper 7 in order to bring the stamper 7 into close contact with the mirror surface of the mirror block 20.

[0031]

According to the first aspect of the present invention, it is possible to prevent gas generated when the molding material heated and melted is injected and filled into the cavity from entering and staying in the space inside the stamper outer peripheral pressing member. can do. Therefore, it is possible to prevent disc molding defects due to mixing of liquefied or solidified deposits from the gas into the air blown out at the time of mold release, and to significantly reduce the disc molding yield and improve production efficiency. Can be provided.

According to the structure of the second aspect, the gas generated from the molding material flows out of the parting line by the low-pressure air supplied from the air supply source through the pressure adjusting means for preventing gas accumulation. Without relying on
It is possible to provide a disk molding die that can easily flow out of the die.

According to the structure of the third aspect, the disk can be formed without affecting the injection of the molding material and without causing gas to stay in the space in the stamper outer peripheral pressing member. Therefore, it is possible to prevent disc molding defects due to mixing of liquefied or solidified deposits from the gas into the air blown out at the time of mold release, and to significantly reduce the disc molding yield and improve production efficiency. And a method of forming a disk that can perform the above method.

[Brief description of the drawings]

FIG. 1 is a sectional view of a disk molding die according to the present invention.

FIG. 2 is a partially enlarged view of FIG.

FIG. 3 is a time chart showing a method of forming a disk according to the present invention.

FIG. 4 is a sectional view of a conventional disk molding die.

FIG. 5 is a partially enlarged view of a conventional disk molding die.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed mold 2 Movable mold 3 Cavity 7 Stamper 16 Air supply passage 40 Passage 41 Movable first air passage 42 Movable second air passage 43 Air suction passage 50 Switching valve 51 Pressure adjusting valve (release air pressure adjusting means) ) 52 Pressure regulating valve (pressure regulating means for preventing gas accumulation) 53 Air supply source

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B29C 45/26 B29C 45/43

Claims (3)

(57) [Claims] 1. A fixed mold and a movable mold that form a cavity in an abutting surface, a stamper disposed on one of the mirror surfaces of the fixed mold and the movable mold, and an outer periphery of the stamper having a slight gap. A holding member for holding the outer periphery of the stamper;
In a disk molding die having an air supply passage opening into a space formed in a stamper outer peripheral holding member and an air supply source supplying air to the air supply passage, the air of the air supply source is supplied to a molded disk. Release pressure adjusting means for supplying to the air supply passage at a pressure required for release of the mold, and pressure adjusting means for preventing gas stagnation to be supplied to the air supply path at a pressure lower than the release pressure. A disk molding die, which is provided. 2. The method according to claim 1, wherein a slight gap communicating with the cavity is formed between the stamper outer peripheral pressing member and the other mold, and a passage communicating the gap with the outside of the mold is provided. Item 10. A disk molding die according to Item 1. 3. A mold closing step of bringing the movable mold into close contact with the fixed mold, a mold clamping step of increasing the pressure of the joined molds, and a step formed on the contact surface of both molds. In a disk molding method of sequentially performing an injection step of injecting and filling a molding material heated and melted in a cavity, a cooling step of cooling and solidifying the molding material, and a mold opening step of separating a movable mold from a fixed mold, When releasing the molded disk, high-pressure air blowing having a pressure required for releasing the disk is performed from an air supply passage opening into a space formed in the stamper outer peripheral holding member, and further, into the cavity. When injecting and filling the heat-melted molding material, air is blown out from the air supply passage at a pressure necessary and sufficient to prevent gas from entering the space in the stamper outer peripheral pressing member. Form method.