JPH0379322A - Disk molding die - Google Patents

Abstract

PURPOSE:To punch a disk center hole without scoring of a male cutter and a female cutter by moving the male cutter forward until the same is brought into contact with a sprue bush and solidifying a resin material, and then opening a mold, projecting an ejected sleeve and working the same. CONSTITUTION:In the state that a resin material 38 is still flowable, a male cutter 24 is projected to a position of being in contact with a sprue bush 16, and the male cutter 24 and the sprue bush 16 are brought together as close as possible, and the resin material 38 is cooled and solidified in the state that a very thin resin layer 40 is formed between the surfaces facing each other. After that, when a disk 18 is released from a moveable mold 12 by the ejecting motion of the ejector sleeve 22, a resin connection section 46 of a solidified section of the resin layer 40 is cut on its outer peripheral edge to punch a central hole 20 of the disk 18. Thus, the disk 18 with the central hole 20 is formed in a space between the male and female cutters without scoring.

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a disk molding mold used for molding disks such as optical disks and magnetic disks, and particularly relates to a disk molding mold that is easy to maintain and manage. It is.

(Foreground Technology) Disks such as optical disks and magnetic disks are usually manufactured by injection molding techniques. In the injection molding process, a sprue bushing is inserted into a donut-shaped cavity formed between a fixed mold and a movable mold through an inner hole of a sprue bushing arranged concentrically with the cavity on the fixed mold side. By injecting the resin material, a disk with predetermined information transferred thereon is molded in the cavity, while an ejector sleeve arranged on the movable mold side concentrically with the sprue bushing is ejected to extrude the disk. At the same time as releasing the mold from the movable mold, the ejector pin disposed at the center of the ejector sleeve is pushed out to release the resin portion of the center hole of the disk solidified within the sprue bush from the movable mold. A disc mold with a similar structure is generally used.

In this type of conventional disk mold, after the resin in the cavity and sprue bush has solidified, the male cutter placed on the movable mold side is cut into the female cutter placed on the fixed mold side. The central hole of the disk is punched out into the cutter, and therefore, a galling phenomenon inevitably occurs between the male cutter and the female cutter, and the galling phenomenon causes them to There was a problem in that the male and female cutters, especially the male cutter, were easily damaged. If the male cutter placed on the movable mold side is damaged in this way, the male cutter must be replaced, which requires disassembling the movable mold and takes a lot of time. there were.

(Solution Section N) The present invention was made against the background of the above, and its object is to eliminate the galling phenomenon between the male cutter and the female cutter. To provide a disk molding die that can punch and form a disk center hole using a male cutter placed on the movable die side, has a long male cutter life, and is easy to maintain and manage.

(Solution Means) In order to solve this problem, in the present invention, as described above, in the donut-shaped cavity formed between the fixed mold and the movable mold, there is a mold that is concentric with the cavity. By injecting a predetermined resin material through the inner hole of a sprue bush disposed on the fixed mold side, a donut-shaped disc with predetermined information transferred thereon is molded in the cavity. The ejector sleeve disposed on the movable mold is concentrically protruded to release the disk from the movable mold, and the ejector pin disposed at the center of the ejector sleeve is protruded to release the disc from the movable mold. In a disc molding mold in which the solidified resin part of the central hole of the disc is released from the movable mold, the sprue bush is always placed with its tip end facing the cavity side with respect to the fixed mold. A male cutter having the same outer diameter as the sprue bushing is provided between the ejector sleeve and the ejector pin, and has the same outer diameter as the sprue bushing. The sprue bushing is provided movably between a retracted position in which an annular gate with a predetermined gap is formed between the sprue bushing and an advanced position in which the annular gate is substantially in contact with the sprue bushing; A cutter pushing means is provided which can advance the male cutter from the retracted position to a position where it substantially abuts the sprue bushing against the pressure of the resin material injected.

Note that the position where the male cutter substantially contacts the sprue bush is defined as the position where the male cutter is in contact with the sprue bush to such an extent that the resin solidified between those opposing surfaces can be easily cut by the ejector sleeve's protruding operation. The position where the sprue bush approaches the sprue bush.

(Function/Effect) In such a disc mold, after the resin material is injected into the cavity, the male cutter is pushed into the sprue bush by the cutter extrusion means while the resin material is still in a fluid state. After the resin material is solidified in this state, the mold is opened, and the ejector sleeve is projected and operated to punch out the center hole of the disc.

In other words, if the disk molding die according to the present invention is used,
By using the group cutter placed on the movable mold side, the group cutter is not inserted into the female cutter as in conventional disk molding molds, and without the galling phenomenon between the group cutter and the female cutter. The center hole of the disk can be punched out, therefore, damage to the group cutter due to such galling phenomenon can be effectively prevented, and the frequency of troublesome replacement of the group cutter can be greatly reduced. This makes maintenance and management of the mold significantly easier.

Further, according to the disc molding die according to the present invention, the facing surface of the sprue bush and the group cutter that connects the disc solidified within the cavity and the resin portion of the central hole of the disc solidified within the sprue bush The center hole of the disk can be punched and formed by simply cutting the extremely thin resin connecting part between them by the ejector sleeve's ejecting action.This allows the inner surface of the center hole of the disk to be finished smoothly, and it is also possible to form the center hole of the disk using a conventional mold. In this case, a paris as shown in Fig. 8 was formed at the axial edge of the disk center hole.
(burrs) can also be eliminated, and the cut edge of the center hole of the disk can be greatly improved.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

First, FIG. 1 shows a disk molding process according to the present invention in which a fixed mold 10 and a movable mold 12 are matched and a donut-shaped cavity 14 is formed between the molds 10 and 12. A cross section of the main part of the mold is schematically shown.

There, 16 is a sprue bush for guiding a predetermined resin material into the cavity 14, and is fixedly disposed on the fixed mold 10 concentrically with the cavity 14. As is clear from the figure, the outer peripheral surface of the sprue bush 16 substantially defines the inner peripheral surface of the cavity 14, in other words, the outer peripheral surface of the sprue bush 16 substantially defines the inner peripheral surface of the cavity 14.
The center hole 20 of the disk 18, which will be described later, is solidified and formed within the
(See Figure 4)
0 by a predetermined distance from the cavity forming surface.

On the other hand, in FIG. 1, reference numeral 22 denotes an ejector sleeve for releasing a disk 18, which will be described later, molded within the cavity 14 from the movable mold 12, and a sprue bush disposed in the fixed mold lO. 16, and has a retracted position where the tip surface is flush with the cavity forming surface of the movable mold 12, and a tip surface that protrudes from the retracted position toward the fixed mold 10 side with a predetermined dimension. The ejector sleeve can be moved in the axial direction between the ejector sleeve and the protruding position using a conventional ejector sleeve moving means (not shown).

The movement stroke of the ejector sleeve 22 by the ejector sleeve movement means is set to be larger than the movement stroke of the group cutter 24, which will be described later, by a predetermined amount.

The inner peripheral surface of the ejector sleeve 22 has a retracted position (retracted position) where the distal end surface is flush with the distal end surface of the ejector sleeve 22 at the retracted position, and a retracted position where the distal end surface is flush with the distal end surface of the ejector sleeve 22 at the retracted position.
4, the sprue butt is movable between a protruding position (advanced position) in which it can substantially abut against the tip surface of the sprue butt 16 (the state in which the molds are aligned at 10 degrees and 12 degrees). A group cutter 24 having the same outer diameter as the blade 16 is disposed so as to be movable in the axial direction, and the group cutter 24 is movable between the retracted position and the extended position at the base end of the group cutter 24. A double-acting cylinder (not shown) is provided for this purpose. The group cutter 24 is held at its retracted position by the reciprocating cylinder when injecting a resin material 38 (described later) into the cavity 14 through the inner hole of the sprue bush 16. An annular gate 26 with a predetermined gap between it and the tip surface.
On the other hand, after the injection of the resin material into the cavity 14 is completed, the resin material 38
The sprue bush 16 is moved forward by the reciprocating cylinder while the sprue bush 16 is still in a flowable state.
(see FIG. 2), and thus the inner circumferential surface of the cavity 14, in other words, the disk 18 to be described later.
substantially defines a central hole 20 of the sprue bushing 16 .

Further, a through hole 28 is formed in the male cutter 24 passing through its center in the axial direction, and an ejector pin 30 is fitted into the through hole 28 so as to be slidable in the axial direction. has been done. The male cutter 22 is located at the base end of the ejector pin 30 and is in the retracted position.
A retracted position (see Fig. 1) where the tip surface of the male cutter "22 is drawn into the through hole 28 of a predetermined size, and a tip surface of the male cutter" 22 that is closer to the fixed mold 10 of a predetermined size than the tip surface of the male cutter "22" in the protruding position. A conventional ejector pin moving means (not shown) is provided for moving the ejector pin 30 between the ejector pin 30 and the protruding position (see FIG. 5).As will be described later, such ejector pin moving means The disk center hole 20, which will be described later, is solidified within the sprue bush 16 by the ejector pin 30 ejecting.
The sprue resin 32 (see Fig. 4), which is the resin part of
It can be released from the movable mold 10.

Here, as shown in FIG. 1, the through hole 28 formed in the male cutter 24 is located at a portion that defines the molding space for the sprue resin 32, and the sprue resin 32
A circumferential annular groove 34 is formed in an undercut shape with respect to the pulling direction. As a result, as will be described later, when the molds 10 and 12 are opened, and when the ejector sleeve 22 is ejected prior to the ejector pin 30 ejected, the sprue resin is solidified within the sprue bush 16. 32 is inserted into the male cutter 24 based on its engagement with the annular groove 34 of the through hole 28.
It is designed to remain as is.

Next, the operation when molding the disk 18 using such a mold will be explained.

That is, when injection molding the disk 18 using such a mold, first, the ejector sleeve 22, ejector pin 30, and male cutter 24 are retracted to their respective retracted positions by the corresponding moving means and double-acting cylinder. In the held state, the movable mold tool 2 is fitted to the fixed mold 10. As a result, those molds 10
．． A cavity 14 is formed between the sprue bush 16 and the male cutter 24, and a predetermined gap (usually about 0.1 to 0.4 mm) is formed between the sprue bush 16 and the male cutter 24.
An annular gate 26 is formed.

When the movable mold 12 is matched with the fixed mold 10 and the cavity 14 and gate 26 are formed, the injection nozzle 3 whose nozzle touches the sprue bush 16 is in that state.
6 to the inner bore of the sprue bush 16 and the gate 26
Through this, a predetermined resin material 38 is injected into the cavity 14 (see FIG. 1). When the injection operation of the resin material 38 into the cavity 14 is completed, the male cutter 24 is inserted into the double-acting cylinder (not shown) while the resin material 38 is still in a flowing state at or before or after the end of injection holding. The sprue bushing 16 is operated to protrude at
(see FIG. 2).

That is, even if the male cutter 24 is
6, it is difficult to completely crush the resin material 38 located between the sprue bush 16 and the male cutter 24. As shown in FIG. 2, a thin film-like resin layer 40 with a thickness of about 0.1 m or less is formed, which can be easily cut by the ejecting operation of the ejector sleeve 22, which will be described later. It is. In this sense, the forward movement of the double-acting cylinder brings the male cutter 24 into substantial contact with the sprue bush 16.

Note that, as is clear from the above description, here, a reciprocating cylinder (not shown) provided at the base end of the male cutter 24 constitutes cutter pushing means for moving the male cutter 24 forward.

When the male cutter 24 is brought into substantial contact with the sprue bush 16, the resin material 38 within the cavity 14 and the sprue bush 16 is cooled and solidified in that state. Then, after a preset cooling and solidification period has elapsed,
Once the resin material in the cavity 14 and the sprue bush 16 has solidified, the movable mold 12 is opened from the fixed mold 10 and the resin material in the cavity 14 and the sprue bush 16 is solidified. The solidified sprue resin 32 is both released from the fixed mold 10.

Note that a stamper (not shown) on which predetermined information is engraved is disposed on the cavity forming surface of the 10 movable molds, similar to the conventional disk molding mold.
The information of the stamper is transferred to the disk 18 molded therein by the solidifying action of the resin material 38.

When the molds 10 and 12 are opened, as shown in FIG. Chuck 44 is inserted. and,
As shown in FIG. 4, first, only the suction pad 42 is suctioned onto the disk 18.

When the suction pad 42 is attracted to the disk 18, the ejector sleeve moving means (not shown) moves the suction pad 42 onto the disk 18.
The ejector sleeve 22 is ejected from the retracted position to the extended position, and the disc 18 is released from the movable mold 12 (stamper), and the releasing operation of the disc 18 punches out the central hole 20 of the disc 18. It will be done.

That is, the disk 18 solidified within the cavity 14 and the sprue resin 32 solidified within the sprue bush 16, which are ejected by the ejector sleeve 22's ejecting operation, are separated from the sprue bush 16 as described above. Extremely thin resin Ji4 between male cutter 24
The sprue resin 32 solidified within the sprue bush 16 is only connected by the resin connection portion 46 which is the solidified portion of the sprue bush 16 as described above. Since the disc 18 is held in the male cutter 24 by engagement with the annular groove 34 formed in the hole 28, the release operation of the disc 18 from the movable mold 12 causes the disc 18 to be released as shown in FIG. Sprue bush 22
The solidified sprue resin 32 is very easily cut from the disk 18 at the outer peripheral edge of the resin connecting portion 46, thereby punching out the central hole 20 of the disk 18.

When the disk 18 is released from the movable mold 12 by the protruding operation of the ejector sleeve 22 and the central hole 20 of the disk 18 is punched out, the ejector pin 30 is inserted into the ejector as shown in FIG. The sprue resin 32 is pushed out from the retracted position to the extended position by the pin moving means, and is separated from the male cutter 24 and released from the movable mold 12. In this state, the sprue resin 32 is gripped by the sprue chuck 44, and in this grip, the ejector sleeve 22°, the ejector pin 30, and the male cutter 24 are pulled into their respective retracted positions (see FIG. 6). The suction pad 42 and the sprue chuck 44 are pulled out from between the molds 10.12, and the disk 18 and the sprue resin 32 are taken out of the mold. First, the grip on the sprue resin 32 is released and the sprue resin 32 is dropped and stored in a predetermined container, and then the disk 18 is transferred to a predetermined stocker to complete a series of molding cycles.

In other words, the information on the stamper is transferred to one side of the center hole 2.
A disk 18 having 0 is obtained.

When molding the disk 18 using the mold of this embodiment, as described above, the male cutter 24 presses the sprue bush 1 while the resin material 38 is still flowable.
6, the male cutter 24 and the sprue bush 16 are brought as close as possible, and an extremely thin resin layer 40 is formed between their opposing surfaces. The material 38 is cooled and solidified, and then
When the disk 18 is released from the movable mold 12 by the ejector sleeve 22 ejecting, the resin connecting portion 46, which is the solidified portion of the resin layer 40, is cut at its outer peripheral edge, and the central hole 20 of the disk 18 is cut. Because it is formed by punching, the male cutter 24 will not be pushed into the female cutter and cause galling, unlike conventional molds, and the male cutter 24 will not The cutter 24 will not be damaged. In other words, the frequency of damage to the male cutter 24 increases to the extent that galling does not occur between it and the female cutter. Therefore, the frequency of replacement of the male cutter 24 is reduced by that amount, and mold maintenance and This makes management easier.

In addition, when molding the disk 18 using the mold of this embodiment, as described above, the extremely thin film-like resin connecting portion 46 solidified between the facing surfaces of the male cutter 24 and the sprue bush 16 is However, when the disk 18 is released from the movable mold 12, the disk 18 is only cut at its outer peripheral edge.
Since the center hole 20 of is formed by punching, the center hole 2
The cut end of the disc is finished extremely smoothly, and as shown in Fig. 7, the burr (which was formed at the axial edge of the disk center hole when using a conventional mold) has been eliminated.
(see Figure 8) is avoided, and therefore,
The result is a disk 18 having a central hole 20 with significantly improved cut edges compared to disks molded using conventional molds.

Although one embodiment of the present invention has been described in detail above, this is a literal illustration, and the present invention is not limited to such a specific example, and within the scope of the spirit thereof,
Of course, the present invention can be implemented with various changes, modifications, improvements, etc.

For example, in the embodiment described above, the cutter pushing means that moves the male cutter 24 forward is configured with a double-acting cylinder that moves the male cutter 24 forward and backward in the axial direction.
While the cutter pushing means is constituted by a simple protruding means such as a single-acting cylinder, the return of the male cutter 24 to the retreated position is carried out by urging means such as a spring or by a sprue bush 16.
It is also possible to make the resin material injected into the mold at a resin pressure of 3 days.

Further, the protruding position of the male cutter 24 is
Although it is desirable that the male cutter 2 be aligned with the position where it contacts or substantially contacts the sprue bush 16, the male cutter 2 should be positioned slightly forward of the position where it contacts the sprue bush 16 once.
It is also possible to set four protruding positions.

[Brief explanation of drawings]

FIG. 1 is a sectional view schematically showing a main part of an example of a disk molding mold according to the present invention, and FIG. 2 is a sectional view showing a protruding state of a male cutter of the mold of FIG. FIG. 3 corresponds to FIG. 1, which shows the movable mold of the mold in FIG. 1 together with a suction bat and a sprue chuck inserted between the fixed mold and the movable mold. FIG. 4 is a diagram corresponding to FIG. 1 showing the movable mold of the mold of FIG. 1 in a state where the disk is released from the mold, and FIG.
FIG. 6 is a diagram corresponding to FIG. 1 showing the movable mold of the mold of FIG. 1 in a state where the sprue resin is released from the mold, and FIG.
7 is a view corresponding to FIG. 1 showing the movable mold of the mold shown in the figure just before the disc and sprue resin are taken out of the mold; FIG. FIG. 3 is a cross-sectional view of a main part of the disc for explaining how a central hole is formed. FIG. 8 is a view corresponding to FIG. 7 of a disk molded using a conventional mold. 10: Fixed mold 12: Movable mold 14: Cavity 16: Spruce bush 18: Disc 20; Center hole 22: Ejector sleeve 24: m cutter 26: Gate 30: Ejector pin 32; Sprue resin 34] Annular groove 46: Resin Connecting part

Claims (1)

[Claims] A predetermined resin material is introduced into a donut-shaped cavity formed between a fixed mold and a movable mold through an inner hole of a sprue bushing arranged concentrically with the cavity on the fixed mold side. By injecting, a donut-shaped disk with predetermined information transferred is formed in the cavity, while
An ejector sleeve disposed on the movable mold is protruded concentrically with the sprue bushing to release the disk from the movable mold, and an ejector pin disposed at the center of the ejector sleeve is protruded to release the sprue bush. In the disc molding mold, the resin part of the central hole of the disc that has been solidified in the disc is released from the movable mold, and the sprue bushing is placed with respect to the fixed mold so that its tip is on the side of the cavity. A male cutter having the same outer diameter as the sprue bushing is provided between the ejector sleeve and the ejector pin, and has the same outer diameter as the sprue bushing. the sprue bushing is provided movably between a retracted position in which an annular gate with a predetermined gap is formed between the sprue bushing and a forward position in which the annular gate is substantially in contact with the sprue bushing; A mold for forming a disk, characterized in that a cutter extrusion means is provided that can advance the male cutter from the retracted position to a position where it substantially abuts the sprue bushing against the pressure of the resin material.