JPH05309696A - Injection mold for disc - Google Patents

Abstract

PURPOSE:To prevent the dragging between both taper parts by fixing an injection mold for a disc to the fixed plate and movable plate of an injection molding machine and closing a fixed mold and a movable mold to align both of them by the mutual taper matching of the locating blocks provided to both molds. CONSTITUTION:The relative position of a fixed locating block 17 and an outer peripheral ring 100 at the time of clamping is determined by the taper matching of an inner peripheral taper part 18 and an outer peripheral taper part 110. Since the relative position of the outer peripheral ring 100 to a movable locating block 23 can be changed, even when misalignment is generated between the fixed locating block and the movable locating block, the relative position of the fixed locating block 17 and the outer peripheral ring 100 is determined regardless of misalignment of both locating blocks. By this constitution, the relative position of a fixed mirror surface plate 19 whose relative position to the fixed locating block 17 is fixed and the outer peripheral ring 100 is also determined in the same way.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for an injection molding machine for injection molding disks such as video disks and compact disks.

[0002]

2. Description of the Related Art Conventionally, various disk injection molding apparatuses for molding video disks, compact disks and the like have been known, for example, the apparatus described in Japanese Patent Publication No. 62-45809 and the Japanese Patent Publication No. 63-45293. There is a device.

FIG. 7 shows a cross-sectional view of the cavity peripheral portion of these conventional devices when the mold is closed. In these conventional devices, the taper portion of the outer peripheral ring 501 fixed to the movable side locating block 511 is shown. 503 and the taper portion 507 of the mirror surface plate 505 of the fixed-side die form a gap serving as a gas escape path during injection molding. Width of gas escape passage formed here (distance between taper portion 503 to taper portion 507)
The molten resin is formed to be extremely narrow because it is necessary to hold the molten resin in the cavity 509 and allow only gas to pass therethrough, and it is usually about 5 to 30 μm. In order to accurately form the width of the gas escape passage, the movable side mold and the fixed side mold are aligned by tapering 515a between the movable side locating block 511 and the fixed side locating block 513.
515b.

[0004]

However, in the mold of the conventional disk injection molding apparatus, the taper portion 503 and the taper portion 503 are caused by a slight deviation in the parallelism of the apparatus and a slight deviation in the dimensional accuracy of the mold. There was a case where "507" was in a "kaziri" state. In the case of "caulking", the gas escape passage is not formed accurately, so the width of the gas escape passage exceeds the allowable range over a part or the entire circumference, and there is a problem that burrs are generated on the peripheral edge of the molded disc. It was

Therefore, the present invention has an object to solve the above-mentioned problems and is intended for a disk capable of forming a good disk without burrs on the peripheral edge by preventing "stripping" between the taper portion 503 and the taper portion 507. It is to provide an injection mold.

[0006]

The present invention adopts the following constitution as means for solving the above problems. That is,
The disc injection-molding die of the present invention comprises a fixed-side die fixed to a fixed plate of an injection-molding machine and a movable-side die fixed to a movable plate. The mold includes a mirror plate that forms a disk-shaped cavity between the joint surfaces when closed, and an outer peripheral ring that is installed around the outer periphery of the mirror plate and that holds an outer edge of a stamper attached to the mirror plate. In a disk injection-molding die provided on one side, the outer periphery of the outer peripheral ring and a locating block of the other die are provided with taper portions that can be mutually tapered, and the outer peripheral ring is a mirror surface surrounding the outer peripheral ring. A gap having a predetermined width is formed between the outer peripheral surface of the board and the inner peripheral surface of the outer peripheral ring facing the outer peripheral surface, and the one die is elastically movable so as to be movable in parallel within the width range of the gap. Through, characterized in that attached.

[0007]

[Function] Prior to the injection of the molten resin, the disk injection molding die is fixed to the fixed plate and the movable plate of the injection molding machine, and the mold is closed. By aligning the locating blocks provided on both the fixed-side mold and the movable-side mold with each other, the two molds are aligned.

At this time, the taper portion is provided also on the outer periphery of the outer peripheral ring and the taper portion provided on the locating block of the mating die. If there is a misalignment between the outer peripheral ring and the mating mold, contact deviation occurs in the taper alignment. However, since the outer peripheral ring can move in parallel within the range of the space formed between the outer peripheral surface of the mirror surface plate and the outer peripheral surface of the mirror surface plate, if there is a strong contact portion in the taper alignment, the pressing force from that portion causes Move away. As a result, the contact in the taper alignment becomes uniform, and the outer peripheral ring and the mating mold are properly aligned.

As a result, the alignment between the taper portion of the inner circumference of the outer peripheral ring and the taper portion of the mirror surface plate of the mating die becomes proper, and the width of the gas escape passage formed between both taper portions is proper. Because of the width, galling between both tapered portions is prevented. In addition, the occurrence of burrs on the outer edge of the disc due to the scoring is prevented, and a good disc can be molded.

[0010]

[Embodiment] A preferred embodiment will be described in detail below. Although a partial cross-sectional view is shown in FIG. 1, the injection molding die 1 for a disk of the present embodiment has a fixed plate 7 which is fastened and fixed to a plurality of stays 3 with nuts 5, respectively, and slides along the stays 3. It is used by being attached to an injection molding machine (not shown) via a movable plate 9 movably attached. This device is capable of forming a disk-shaped cavity 11 by pressing the fixed plate 7 and the movable plate 9 after the assembly and for injection-molding a disk such as a compact disk.

A fixing member 15 and a fixed locating block 17 are fixed to the fixing plate 7 by bolts (not shown).
A fixed mold 20 including a fixed side mirror surface plate 19 is attached. In addition, the movable platen 9 is also movable by bolts (not shown), and includes a first movable member 21a, a second movable member 21b, a third movable member 21c, a movable side locating block 23, and a movable side mirror surface plate 25. A mold 26 is attached.

The fixed mold 20 and the movable mold 26 are
The molds can be closed and opened so that they can face each other. When the mold is closed, the fixed-side locating block 17 and the movable-side locating block 23 are in close contact with each other, so that the space between the cavity surface 27 of the fixed-side mirror surface plate 19 and the cavity surface 29 of the movable-side mirror surface plate 25 is described above. Cavity 11 is formed.

At the time of injection molding, a stamper 30 having irregularities corresponding to the disk to be molded is attached to the cavity surface 29 of the movable side mirror surface plate 25. The unevenness is transferred to the information surface of the molded disk to form an information area. Therefore, to be precise, the cavity 11 is formed between the cavity surface 27 of the fixed-side mirror surface plate 19 and the stamper 30.

Further, a taper portion 19a is formed on the outer circumference of the fixed mirror surface disk 19, and an outer peripheral surface 25a is formed on the outer circumference of the movable mirror surface disk 25. Furthermore, each mirror surface board 19, 2
5 is provided with a cooling groove 31 for preventing heating so that it can be cooled by a refrigerant flow.

First, the structure on the fixed mold 20 side will be described. The schematic structure of the fixed mold 20 is such that a substantially disk-shaped fixing member 15 and a fixed-side mirror surface plate 19 are fitted into a fixed-side locating block 17. The fixed-side locating block 17 is a substantially square plate-shaped body having a hole around the central axis. The fixed-side locating block 17 is provided with a circumferential protrusion 18 having a trapezoidal cross section and having an outer tapered portion 18a and an inner tapered portion 18b at a predetermined distance from the outer edge of the fixed-side locating block 17. There is.

Through holes 33a, 33b are formed in the fixed member 15 and the fixed side mirror surface plate 19 along the central axis. A fixed sleeve 35 is provided which is fitted into the through holes 33a and 33b and opens at the center of the fixed-side mirror surface plate 19.

Further, a sprue bushing 37 is provided so as to fit inside the fixed sleeve 35. The sprue bushing 37 is formed with an injection port 39 which opens along the central axis of the sprue bushing 37 in the center of the fixed-side mirror surface plate 19.
A nozzle contact surface 41 is formed at the rear end of the sprue bushing 37.

A nozzle guide 45 having a nozzle insertion hole 43 is externally fitted to the rear end of the sprue bushing 37. Next, the structure on the movable mold 26 side will be described. Behind the movable platen 9, a mold clamping ram 55 for advancing and retracting the movable platen 9 with respect to the fixed platen 7 is fixed by bolt fastening. The mold clamping ram 55 is connected to a piston inserted in a mold clamping cylinder (not shown), and has a function of sliding the movable plate 9 forward and backward along the stay 3. As a result, the movable mold 26 is closed with respect to the fixed mold 20,
Each operation of mold clamping and mold opening can be performed.

The ejector pin 57 is penetrated through the movable platen 9.
a and 57b are provided. Ejector pin 57a,
One end of 57b is connected to a hydraulic piston (not shown). The ejector pins 57a and 57b are reciprocally driven by being driven by the hydraulic piston.

The other end of the ejector pin 57a penetrates through the first movable member 21a to form an ejector sleeve 65.
It abuts the rear end. The ejector sleeve 65 is
The second movable member 21b, the third movable member 21c, and the movable side mirror surface plate 25 are penetrated. At the same time, the ejector sleeve 65 is slidably inserted into the ejector bushing 67 fitted to the third movable member 21c and the stamper holder 69 fitted to the movable side mirror surface plate 25.

The front end of the ejector sleeve 65 reaches the cavity 11, and the rear end is provided with a flange portion 65a. A spring 71 is arranged between the flange portion 65a and the ejector bushing 67 so as to urge the flange portion 65a toward the first movable member 21a. The ejector sleeve 65 causes the flange portion 65a to contact the first movable member 21a by the action of the spring 71. However, when the ejector pin 57a presses the flange portion 65a, the ejector sleeve 65 advances against the spring 71 and moves inside the cavity 11. It is possible to project to. Further, the spring 71 is housed in the second movable member 21b, and the ejector sleeve 65 is
Is formed to allow reciprocal movement.

A cutter punch 73 is inserted into the ejector sleeve 65. The cutter punch 73 has a flange portion 73a provided at a rear end thereof in contact with the movable platen 9, and a tip end thereof slightly protrudes from a central portion of the cavity 11. The flange portion 73a can reciprocate in the space formed in the first movable member 21a. A spring 75 is arranged in this space so as to bias the flange portion 73a toward the movable platen 9 side. The tip of the ejector pin 57b is in contact with the flange portion 73a. As a result, the flange portion 7 is removed by the ejector pin 57b.
When 3a is pressed, it moves forward against the spring 75, protrudes through the cavity 11, and its tip can be fitted into the opening of the fixed sleeve 35.

Cutter punch 73, ejector sleeve 6
5, ejector bushing 67 and stamper holder 6
9 is concentric, the cutter punch 73 is the ejector sleeve 6
5, the ejector sleeve 65 is
The outer peripheral surface of the cutter punch 73 and the inner peripheral surface of the ejector bushing 67 and the stamper holder 69 are slidable.

Third movable member 21c and movable side mirror surface plate 2
Reference numeral 5 has a shape fitted in the movable-side locating block 23. The movable side locating block 23 is
It is a substantially square plate-like body having a hole around the central axis. A step portion 81 having a taper portion 81a is provided near the outer periphery of the movable side locating block 23.

The taper portion 81a and the outer taper portion 18a formed on the circumferential projection 18 of the fixed-side locating block 17 are formed so as to be aligned with each other. Therefore, when the die is closed, the outer taper portion 18a and the taper portion 81a are in close contact with each other, and the taper is aligned to fix the fixed die 20.
The relative position between the movable mold 26 and the movable mold 26 is defined. Therefore, the centering of the fixed mold 20 and the movable mold 26 is performed by tapering the outer taper portion 18a and the taper portion 81a.

The movable side locating block 23 includes
The outer ring 100 has a bolt 101 and a spring 1.
It is attached via 03. An enlarged cross-sectional view around the outer peripheral ring 100 is shown in FIG. The outer peripheral taper portion 110 formed on the outer periphery of the outer peripheral ring 100 is formed so as to be aligned with the inner taper portion 18b formed on the circumferential protrusion 18 of the fixed-side locating block 17 so as to be capable of being tapered. .. Therefore, when the mold is closed, the inner taper portion 18
The taper b and the outer peripheral taper portion 110 can be in close contact with each other.

A bolt chamber 120 for accommodating the bolt 101 and the spring 103 is formed in the outer peripheral ring 100. Further, a bolt hole 130 communicating with the bolt chamber 120 and opening at both ends is formed. Bolt chamber 1
The inner diameter of 20 is provided with a predetermined gap with respect to the outer diameter of the head of the bolt 101. Further, the bolt hole 130 is provided with a predetermined gap with respect to the shaft outer diameter of the bolt 101. As a result, the relative position between the outer peripheral ring 100 and the bolt 101 is variable in the direction orthogonal to the axis of the bolt 101.

Further, the spring 103 interposed between the outer peripheral ring 100 and the bolt 101 is provided with the outer peripheral ring 10
0 is biased to the movable side locating block 23 side. Therefore, movement of the outer peripheral ring 100 in the direction along the axial direction of the bolt 101 is prevented.

The inner peripheral taper portion 140 formed on the inner periphery of the outer peripheral ring 100 is the taper portion 19a of the fixed side mirror surface plate 19.
It is inclined parallel to and forms a gap between the inner peripheral tapered portion 140 and the tapered portion 19a. The void is
It serves as a gas escape route during injection molding. The width of this gap (the distance between the inner peripheral tapered portion 140 and the tapered portion 19a) is
The width is set so that only gas can pass and molten resin cannot enter. Therefore, only the gas can be discharged from the inside of the cavity 11 to the outside of the cavity 11 through the void.

A stamper holding portion 15 for holding the outer edge portion of the stamper 30 attached to the movable side mirror surface plate 25 is provided in the vicinity of the end of the inner peripheral taper portion 140 on the cavity surface 29 side.
It is 0. The outer edge portion of the stamper 30 attached to the movable side mirror surface plate 25 is sandwiched between the stamper holding portion 150 and the movable side mirror surface plate 25, and the inner edge portion is sandwiched between the stamper holder 69 and the movable side mirror surface plate 25. As a result, the stamper 30 is surely brought into contact with and held by the cavity surface 29. However, the outer edge of the stamper 30 and the stamper retainer 1
The contact pressure with 50 is adjusted to a predetermined value, and the relative position between the stamper 30 and the outer peripheral ring 100 is the cavity surface 2
It can be changed in the direction along 9.

An inner peripheral surface 160 is formed on the inner peripheral portion of the outer peripheral ring 100 facing the outer peripheral surface 25a of the movable mirror surface plate 25. The outer peripheral surface 25a and the inner peripheral surface 160 are parallel to each other, and a gap corresponding to the above-described gap between the bolt hole 130 and the bolt 101 is formed. Next, a case where a disk is injection-molded by using the disk injection molding die 1 of this embodiment will be described. The disk injection molding die 1 is assembled to an injection molding machine (not shown), and a stamper 30 is previously attached to the movable side mirror surface plate 25.

First, the mold clamping ram 55 is advanced to close the movable mold 26, and the mold is clamped to form the cavity 11. The injection molding machine used in this embodiment is of a known type. The injection molding machine that can be used is not particularly limited as long as it is suitable for disk injection molding.

At this time, as shown in FIG.
If the movable mold 26 and the movable mold 26 are accurately aligned, the basic mold closed state as shown in FIGS. 1 and 2 is obtained. However, if there is a slight deviation in the parallelism of the device or a slight deviation in the dimensional accuracy of the mold, for example, as shown in FIG.
0 and the movable mold 26 may be misaligned. When the mold closing progresses in this state, the outer peripheral taper portion 110 of the outer peripheral ring 100 and the inner taper portion 18b of the fixed-side locating block 17 come into contact with each other in a shifted state (FIG. 5).

When the mold closing further progresses from the state of FIG. 5,
The fixed side locating block 17 and the movable side locating block 23 come into contact with each other, and the mold is clamped. Along with mold clamping, the outer peripheral taper portion 11 of the outer peripheral ring 100.
0 is the inner taper portion 1 of the fixed side locating block 17.
8b presses. The pressing force acts along the axial direction of the outer peripheral ring 100, but since the contact surface between the inner tapered portion 18b and the outer tapered portion 110 is inclined, the outer peripheral ring 10
0 is generated in the direction of arrow X in FIG. Since the relative position of the outer peripheral ring 100 is variable with respect to the movable locating block 23 and the stamper 30, the outer peripheral ring 100 moves in the arrow X direction by the pressing force. FIG. 6 shows a cross-sectional view around the outer peripheral ring 100 at the end of the mold clamping.

In this way, the relative position between the fixed-side locating block 17 and the outer peripheral ring 100 at the time of mold clamping is determined by the taper of the inner tapered portion 18b and the outer peripheral tapered portion 110. Moreover, since the outer peripheral ring 100 can change the relative position to the movable side locating block 23, even if the fixed side locating block 17 and the movable side locating block 23 are misaligned, the fixed side locating block The relative position between 17 and the outer peripheral ring 100 is determined regardless of the misalignment.

Since the relative position between the fixed-side locating block 17 and the outer peripheral ring 100 is virtually uniquely determined, the fixed-side mirror surface plate 19 whose relative position with respect to the fixed-side locating block 17 is fixed, Outer ring 10
The relative position with respect to 0 is similarly determined.

Therefore, the relative position between the inner peripheral taper portion 140 of the outer peripheral ring 100 and the taper portion 19a of the fixed side mirror surface plate 19 is always appropriate. Therefore, it is possible to prevent "stripping" between the inner peripheral tapered portion 140 and the tapered portion 19a. As a result, generation of burrs due to the "stripping" is prevented, and a good disc is molded.

After the mold is clamped, the molten resin is injected into the cavity 11 through the injection port 39. After injecting a predetermined amount of molten resin, the ejector pin 57b is advanced to cause the cutter punch 73 to project through the cavity 11. Cutter punch 73
The front end of the is inserted into the opening of the fixing sleeve 35, and the opening is closed, so that the flow of the molten resin into the cavity 11 is stopped. At the same time, the center hole of the disc is formed.

In this state, the solidification of the resin is awaited. When the resin is solidified, the movable platen 9 is retracted by the mold clamping ram 55 to open the mold. Subsequently, when the ejector pin 57a is advanced to project the ejector sleeve 65, the product disc is separated from the stamper 30. This is taken out from the disc injection molding die 1 by means of a suction cup or the like, and the disc molding is completed.

Although the invention of the present application has been described according to the embodiments, the invention of the present application is not limited to the above-described embodiments, and various improvements can be made without departing from the scope of the invention of the present application.

[0041]

As described above in detail, in the disk injection molding die of the present invention, the outer peripheral ring and the mating die are always properly aligned. For this reason, the alignment between the tapered portion on the inner circumference of the outer peripheral ring and the tapered portion of the mirror surface plate of the mating mold is also proper, and the width of the gas escape passage formed between both tapered portions is also a proper width. Therefore, galling between both taper portions is prevented. In addition, the occurrence of burrs on the outer edge of the disc due to the scoring is prevented, and a good disc can be molded.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an injection-molding die for disc according to an embodiment.

FIG. 2 is a partially enlarged cross-sectional view of the disk injection molding die of the embodiment.

FIG. 3 is an explanatory diagram of the relative positions of the fixed and movable locating blocks and the outer peripheral ring of the disk injection molding die of the embodiment.

FIG. 4 is an explanatory diagram of the relative positions of the fixed and movable locating blocks and the outer peripheral ring of the disk injection molding die of the embodiment.

FIG. 5 is an explanatory diagram of the relative positions of the fixed and movable locating blocks and the outer peripheral ring of the disk injection molding die of the embodiment.

FIG. 6 is an explanatory diagram of the relative positions of the fixed and movable locating blocks and the outer peripheral ring of the disk injection molding die of the embodiment.

FIG. 7 is an explanatory diagram of the vicinity of an outer peripheral ring of a conventional disk injection molding die.

[Explanation of symbols]

1 ... Injection mold for disk, 7 ... Fixed platen, 9
... Movable plate, 11 ... Cavity, 17 ... Fixed side locating block, 18a ... Outer taper part,
18b ... Inner taper part, 19 ... Fixed side mirror surface plate, 2
0 ... Fixed mold, 23 ... Movable locating block, 25 ... Movable mirror surface plate, 25a ... Outer peripheral surface, 26 ... Movable mold, 30 ... Stamper, 100
... Outer ring, 101 ... Bolt, 103 ...
Spring, 110 ... Tapered outer circumference, 120 ...
Bolt chamber, 130 ... Bolt hole, 140 ... Inner peripheral taper portion, 150 ... Stamper pressing portion, 160 ... Inner peripheral surface, 501 ... Outer peripheral ring, 503, 507 ...
Tapered part, 505 ... Mirror surface plate, 511 ... Movable side locating block, 513 ... Fixed side locating block,

Claims (1)

[Claims] 1. A fixed-side mold fixed to a fixed plate of an injection molding machine and a movable-side mold fixed to a movable plate, the both molds being a joint surface when the both molds are closed. A disk provided with a mirror surface plate for forming a disk-shaped cavity therebetween, and an outer peripheral ring which is installed around the outer periphery of the mirror surface disk and holds an outer edge portion of a stamper attached to the mirror surface disk on one of the molds. In an injection molding die for use, a taper portion capable of being tapered with each other is provided on the outer periphery of the outer peripheral ring and the locating block of the other die, and the outer peripheral ring is provided with an outer peripheral surface of a mirror surface disk surrounded by the outer peripheral ring. A gap having a predetermined width is formed between the outer peripheral surface and the inner peripheral surface of the outer peripheral ring, and the mold is attached to the one mold via an elastic member so as to be movable in parallel within the width range of the gap. Injection mold disc according to claim.