JPH02223422A - Mold - Google Patents

Abstract

PURPOSE:To prevent hurting of a stamper or defective fitting by making operation easy, by constituting the title mold so that the stamper is kept fitted to a stamper fitting member and fitting or removal of the stamper to or from a mold along with the stamper fitting member is performed. CONSTITUTION:An outer edge part of a stamper 6 is pressed toward the center with positioning devices provided radially at least three positions on a fitting ring 25 of a stamper fitting member 23 and moved backward against a pressing force through extension due to thermal expansion to be followed by heat of molten resin filled into a cavity 10. Then whirl-stop of the stamper 6 at the time of molding is performed by fitting at least one position out of the positioning devices provided at least three positions into a notch provided on the outer edge part of the stamper 6. Fitting or removal of the stamper is performed unitarily along with the stamper fitting member 25 further.

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention relates to a mold for manufacturing an optical disc,
In particular, it relates to improvements in the work of attaching and removing a stamper to a mold, and furthermore, measures to prevent foreign matter such as dust from entering the back side of the stamper.

(Prior Art) A conventional mold for forming an optical disk for a general injection molding machine will be explained with reference to FIG. A mold, 2 is a movable mold, 3 is a fixed ring for molding the outer peripheral surface of the optical disk, and is attached to the fixed mold 1 with bolts 4.
Reference numeral 5 denotes a movable side ring that presses and fixes the outer circumference of the stamper 6, and is attached to the movable mold 2 with bolts 7, and has an inner peripheral surface with a larger diameter than the outer diameter of the stamper so that the stamper 6 can expand outward due to thermal expansion during molding. The clearance T between the inner protrusion 8 of the movable side ring 5 and the stamper 6 is set to the minimum necessary to prevent the stamper 6 from appearing in front of the stamper mounting surface of the movable mold 2. . The stamper 6 is made of nickel and has minute signal pits or grooves carved on its surface on the cavity IQ side. In addition, the protrusion 9 on the inside of the fixed side ring 3
The gap H between the stamper 6 and the stamper 6 is such that the stamper 6 can slide due to thermal expansion, and the resin does not leak when the molten resin is injected into the cavity 10.

A sleeve bushing 11 is provided at the center of the stationary mold 1 (lower part of FIG. 11), and a sprue bushing 12 is provided inside this so as to be movable in the left-right direction in the drawing. When punching out the center hole of the optical disk, the sprue bushing 12 moves to the right side 1, and the optical disk formed in the cavity 10 is cut between the sleeve bushing 1 and the sprue bushing 12. In addition, a cylindrical center presser 13 is inserted into the center hole 14 of the stamper 6 and the hole +43 of the movable mold 2 from the cavity 10 side in the center of the movable mold 2, and positions the stamper 6. It is held in place by pressing down on the center. A center sleeve 5 is attached to a mounting member (not shown) of the movable mold 2 inside the center presser 3, and a punch 16 for punching the center hole of the optical disk is inserted inside the center sleeve 5 so as to be movable in the left and right direction.
When punching out the center hole of the optical disk, it is moved to the right by a cylinder (not shown). Further, inside this punch 16, a protruding pin 17 for protruding a sprue that becomes unnecessary after molding is provided so as to be movable in the left-right direction by a cylinder (not shown). Reference numeral 18 denotes a parting surface, and the parts are separated at this parting surface 18 when the mold is opened.

The movable mold is attached to a movable die plate of an injection molding machine (not shown) via a mounting member (not shown), and the fixed mold is attached to a fixed die plate of the injection molding machine via a mounting member (not shown). .

Next, to explain the operation, the movable die grate of the injection molding machine is moved backward, the movable mold 2 is separated from the fixed mold I, the mold is opened, and then the stamper 6'! ! l- As shown in FIG. 12, with the center stamp 13 inserted into the center hole I4 of the stamper 6, the ring-shaped groove is formed between the movable mold 2 and the center sleeve 15 by holding it between the thumb and forefinger. 19 from the direction of the arrow and attach it. Move the mounting return movement side ring 5 into the ring-shaped mounting groove 20 of the mold 2.
Insert the mounting jig 21 while supporting it by hand from the fixed mold 1 side and fix it to the movable mold 2 with bolts 7. Now stamper 6
installation is complete.

Next, the movable mold 2 is pressed onto the fixed mold 1, and the mold is clamped.
Sprue the molten resin into a bush 12. to fill the cavity 10. Then, the stationary mold 1 and the movable mold 2 are cooled in a pressure-retained state, and when the resin is sufficiently hardened, the sprue bush 12 and punch 16 are moved to the right (in FIG. 11) to punch a center hole in the optical disk. Next, the mold is opened, the protruding pin 17 is moved to the slide pusher 12 side, and the sprue is discharged, and then the molded product is automatically (not shown) automatically, and the operations from mounting the stamper 6 to discharging the molded product are completed.

In the subsequent operations, the stamper 6 repeats the series of operations described above up to step 1.

FIG. 13 shows a part of the stamper mounting structure in another embodiment, which will be explained below.The outer circumference of the stamper 6 is fixed by providing an O-ring groove 8b'r on the stamper 6 side of the inner protrusion 8a of the movable ring 5a. The ring 22 is loaded and the outer periphery of the stamper 6 is moved through the O-ring 22 into the mold 2. It is designed to be pressed into place. The other structures and operations are generally the same as those of the mold described above, so their explanation will be omitted.

(Problem to be Solved by the Invention) The stamper 6 used for manufacturing optical discs has minute signal pits or grooves carved on one side, and its thickness is within the range of 25%.
It is a thin nickel plate with a thickness of ~0.30wn.

Handling is done in a dust-free room, and not only should foreign matter such as dust adhere to the surface, but also human breath should not be exposed to it. Therefore, in conventional molding molds, there are problems with damage to the stamper 6 and the operation required to replace it.However, replacing the stamper 6 is difficult because it must be operated within a narrow mold attached to the molding machine, and the stamper cannot be attached to surrounding members. Problems such as damage caused by contacting the stamper 6 and the stamper 6 have occurred. In addition, the movable side ring 5 is arranged so that the stamper 6 can be expanded by thermal expansion when the stamper 6 is attached to the movable mold 2.
There is a gap T between the inner protrusion 8 and the stamper 6. During molding, the stamper 6 expands and contracts due to the cooling of the high-temperature molten resin and the mold, rotates slightly, and constantly rubs against the contact surface of the movable mold 2, generating nickel powder, which causes the stamper 6 and the movable ring 5 to
Since there is a gap T between the stamper 6 and the protruding part, the stamper 6 rises to form a gap. Foreign matter such as fine dust enters this gap from the outside, causing not only the molded product but also the stamper 6 to be defective.

Furthermore, as shown in FIG. 13, when the outer circumference of the stamper 6 is held down by an O-ring 22 to prevent the outer circumference of the stamper 6 from lifting up, contact wear with the movable mold 2 becomes a major problem. ing.

In order to solve these problems, the present invention provides a molding die that allows the stamper to be easily replaced, prevents damage to the stamper, and prevents poor mounting.

[Structure of the invention]

(Means for Solving the Problem) This molding mold is a mold for molding an optical disc by mounting a stamper with a stamper mounting member in a cavity formed by a fixed mold and a movable mold. The mounting members include a mounting ring with a groove on the stamper mounting part that can be easily removed from either a fixed mold or a movable mold, and a mounting ring with a groove on the stamper mounting part that can be easily removed from either a fixed mold or a movable mold. A stamper stamper is attached to the mounting ring with a slight gap and a stamper stamping process is used to form the outer circumferential surface of the optical disc, which is a molded product. It is composed of a positioning device that presses the outer edge of the stamper toward the center and retreats against the pressing force against elongation due to thermal expansion, and at least one of the three or more positioning devices is located on the outer edge of the stamper. The stamper is engaged with a notch provided to prevent the stamper from rotating, and the stamper is attached and removed integrally with the stamper attachment member.

Also, for the reason described later, there is a problem between the mounting ring near the outer periphery on the back of the stamper and the movable mold, or one of them.
, jl) It is effective to provide a communicating groove or space in the Bakim suction device.

(Function) A positioning device provided radially at at least three locations on the mounting ring of the stamper mounting member presses the outer edge of the stamper toward the center and prevents elongation due to thermal expansion caused by the heat of the molten resin filled in the cavity. , to retreat against the forces of oppression. In addition, the stamper is prevented from rotating during molding by engaging at least one of the three or more positioning devices with a notch provided on the outer edge of the stamper, and the stamper is mounted and removed integrally with the stamper mounting member. Do it on purpose.

Then, the groove or space communicating with the vacuum suction device is vacuumed to remove foreign matter such as nickel powder generated on the outer periphery of the stamper during molding and dust that has entered from the outer periphery, and has penetrated to the signal surface of the stamper. to prevent damage to the stamper.

(Example) An example of the present invention will be described with reference to FIGS. 1 to 7. 1 is a front view, and FIG. 2 is a cross-sectional view taken along the line A-A in FIG. 1, where 23 is a stamper mounting member and 25 is a stamper 6
A mounting ring 26 is a ring-shaped stamper press that molds the outer peripheral surface of the optical disc and presses the stamper 6, and is easily attached to the mounting ring 25 by bolts 27.

Further, the mounting ring 25 is inserted into the ring-shaped mounting groove 2Oa of the movable mold 2a, and is easily detachably attached to the movable mold 2a with bolts 28. The mounting ring 25 is provided with three substantially rectangular, two-tiered through holes 29 arranged radially at three evenly spaced locations. A positioning block 30.45 of the positioning device is mounted so as to be movable in the radial direction (in the direction of the arrow). The positioning device is composed of a positioning block 30, 45, a pressing spring 32, and a set screw 34. The positioning block 30 has an end surface 31 that touches the outer peripheral surface of the stamper 6, and the positioning block 45 has an end surface 46 that touches the bottom surface of the notch 24 of the stamper 6. The 0 positioning block 45, which is designed to press lightly inward with the pressing spring 32 and position the stamper 6 at the forward limit of the positioning blocks 30 and 45, is connected to the positioning block 30 as shown in FIGS. 5 and 6. Slightly different stamper 6. The pressing side of the stamper 6 has a partially convex shape, and this part is inserted into a notch 24 provided at the outer edge of the stamper 6 to prevent the stamper 6 from rotating during molding. One end of the pressing spring 32 is partially inserted into a hole 33 formed in the positioning blocks 30, 45, and the other end is fixed with a set screw 34. In addition, the through hole 2 of the step
9 are each covered with a lid 35. A groove 36 is provided on the inner circumferential portion of the mounting ring 25 on the side where the stamper 6 is attached, so that even if the stamper 6 thermally expands during molding, it can escape to the outside. At this time, positioning block 3
0.45, the pressing spring 32 is fully compressed by the amount of expansion and retreats.

Between the stamper 6 and the stamper presser 26, the stamper 6 can be expanded due to thermal expansion, and the molten resin can be inserted into the cavity 1.
A gap is formed that does not leak when filled to zero. A gap (space) K is formed between the inner peripheral surface 40 of the mounting ring 25 and the inner surface 20b of the ring-shaped mounting groove 20a of the movable mold 2a.

In addition, in a mold that uses vacuum suction to remove foreign matter such as dust that enters the back side of the outer periphery of the stamper, two vacuum suction grooves 41 that communicate with the mounting groove 20a are used.
The grooves 41 provided in the radial direction are connected to a vacuum suction device (not shown) with a hose or the like. The bartending surface of this mold is 18a.

The configuration of the attachment part of the stamper 6 has been explained above.
The rest of the structure is the same as the conventional mold shown in FIG. 1I, so illustration and explanation will be omitted.

Next, the operation will be explained. Stamper 6 with the mold open
To attach the stun nozzle 6, attach the stun nozzle 6 to the mounting ring 25 on a workbench outside the mold.

At this time, the positioning blocks 30, 45' provided at three locations are loosened by loosening the setscrews 34'ff, and then installed inside. After attaching the stamper holder 6, attach the stamper presser 26, fix it to the mounting ring 25 with the bolt 27, and tighten the set screw 3.
When the stamper 4 is moved forward at the predetermined position 1, the outer periphery of the stamper 6 and the bottom surface 47 of the notch 24 are pushed inward by the inner end surface 31.46 of the positioning block 30.45, and the stamper 6 is pushed forward at the advancing limit of the positioning block 30.45. Outer diameter and bottom surface 47
The stamper 6 is positioned at the center with a fair degree of accuracy, almost matching the 2
The stamper 6 assembled into the mounting ring 25 is brought into the mounting groove 20a of the stamper 20a, and is mounted, and then attached to the movable mold 2a with bolts 28. Next, the center presser 13 is inserted into the center hole 14 of the stamper 6 and the tarring-shaped groove I9 formed between the movable mold 2a and the center sleeve I5 for final positioning. Attachment of the stamper 6 is now completed, and a series of molding cycle operations will then begin. The other operations are the same as those of the conventional mold, so the explanation will be omitted. In the case of a molding die that performs vacuum suction, a vacuum suction device (not shown) is activated during molding to connect the inner circumferential surface 40 of the mounting ring 25 and the ring-shaped movable mold 2a via the vacuum suction groove 41. Gently suck the gap K between the mounting groove 20a and the inner surface Qb to remove wear particles of the stamper 6 or foreign matter such as dust that has entered from the outer periphery of the stamper 6 without interfering with engraving or shrinkage of the stamper 6. Suction it and make sure it doesn't get inside this area.

The other operations are the same as those of the conventional mold, so the explanation will be omitted.

FIG. 8 shows another embodiment in which a stamper presser 26a and a fixed ring 26b are provided in place of the stamper presser 260 in FIG. is the birch surface.

In addition, 25a is a mounting ring, nb is a movable mold, 30a is a positioning block, 35a is a lid, and 41a is a groove for vacuum suction, and the structure, operation, and effect are the same as the embodiment shown in FIG. Omitted.

FIG. 9 (FIG. 9) shows a part of the positioning device at one of the three locations in another embodiment of FIG.
The protrusion of the positioning block 45a is inserted into the positioning block 45a, and the end face 46a of the positioning block 45a is pressed against the inside of the bottom face 47 of the notch 24 of the stamper 6.

2. Effects of the Invention] As explained above, the structure of the stamper mounting part of the present invention is completely different from the conventional method, and the stamper is positioned by pressing the outer edge of the stamper toward the center using the positioning device. It is able to escape thermal expansion and also prevents the stamper from rotating, thereby minimizing wear on the stamper.

In addition, the stamper can be installed and removed in a wide space without having to be installed in a narrow mold, and the stamper can be installed and removed from the mold together with the stamper installation member, making operations easier. This can prevent damage to the stamper or improper attachment. Further, in a molding die that performs vacuum suction, foreign matter such as dust that has entered the back surface of the stamper from the outer periphery and abrasion powder of the stamper are removed by vacuum suction, thereby preventing damage to the stamper. Further, since the stamper can be replaced while the stamper is assembled with the stamper mounting member, automatic replacement by a robot is possible, which has a remarkable effect.

[Brief explanation of the drawing]

1 to 7 show an embodiment of the present invention,
Fig. 1 is a front view of the stamper attachment part as seen from the stamper pressing side, Fig. 2 is a sectional view taken along the line A-A in Fig. 1, Fig. 3 is a view taken in the direction of the Z arrow in Fig. 2, and Fig. 4 is a sectional view taken along line B-B in FIG. 3, FIG. 5 is a sectional view taken along line C-C in FIG. 1,
Fig. 6 is a view in the Y direction of Fig. 5, Fig. 7 is an explanatory diagram of the operation when installing the stamper, Fig. 8 is a sectional view showing another embodiment, and Fig. 9 is a sectional view showing another embodiment.
The figure is a sectional view showing a part of another positioning block corresponding to Fig. 8, and Fig. 10 is a plan view showing a part of the stamper.
Figures 11 to 13 show conventional molding molds, with Figure 11 being a sectional view, Figure 12 being an explanatory diagram of the operation when installing the stamper, and Figure 13 showing the main parts of another conventional mold. FIG. a, lb...Fixed mold, 2a, 2b...
・Moving mold, 6...Stamper 10...
... Capity, 23... Stamper mounting member, N5, N5a... Mounting ring, 26.26a.
...Stamper pressing, 26b...Fixed side ring, 45.45a...Positioning block, KSL,
T... Gap.

Claims (1)

[Scope of Claims] 1) A mold for molding an optical disc by mounting a stamper with a stamper mounting member in a cavity formed by a fixed mold and a movable mold, wherein the stamper mounting member is fixed or movable. a mounting ring that is easily removably attached to either side of the movable mold and has a groove provided in the stamper mounting portion to allow thermal expansion of the stamper in the radial direction due to heat generated by filling the cavity with molten material; The outer edge of the stamper is attached to the mounting ring with a slight gap from the surface carved with signal pits, etc., and the stamper presser is used to form the outer peripheral surface of the optical disc, which is a molded product. a positioning device provided radially at three or more locations, which presses the outer edge of the stamper attached to the mounting ring toward the center and retreats against the pressing force against elongation due to the thermal expansion; At least one of the three or more positioning devices is configured to engage with a notch provided on the outer edge of the stamper to prevent rotation of the stamper, and the positioning device is configured to engage with a notch provided at the outer edge of the stamper to prevent rotation of the stamper.
A molding die characterized in that removal is performed integrally with a stamper mounting member. 2) The molding mold according to claim 1, wherein a groove or space communicating with a vacuum suction device is provided between the mounting ring near the outer periphery of the back surface of the stamper and the movable mold, or on either side thereof. Type.