JPS63144028A - Molding tool for disk board - Google Patents

Abstract

PURPOSE:To hold a mold under a parallel state at the time of clamping operation of the mold, by a method wherein a tapered face for alignment of a stationary and movable molds are held under a fitting state during a period when they are shifting in a mold breaking direction from a mold clamping position and meantime they are held under an alignment state. CONSTITUTION:The outermost circumferential part of a mold body 34 is notched annularly so as to demarcate the outer circumferential part of an annular plane 48, the inner circumferential face of an annular notched part is made a tapered face 62 of a predetermined inclination angle and the tapered face 62 is formed on the mold body 34 in a body. A tapered face 64 fitting in the tapered face 62 of a stationary mold 22 side is formed on the inner circumferential face of an outer circumferential ring 66 and the outer circumferential ring 66 is fitted in a cylindrical face 70 of a stepped part provided on the outer circumferential part of a movable side mold body 36 at its cylindrical face 68 slidably, in a movable mold 42 side. The outer circumferential ring 66 is energized toward the stationary mold 22 side always by energizing force of a compression coil spring 86 and the tapered faces 62, 64 of both the molds 22, 24 are held under a fitting state at the time of not only a mold clamping but also a mold breaking.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a mold for a disk substrate, and particularly relates to an injection compression (
The present invention relates to a mold for a disk substrate suitable for use in injection/compression molding.

(Prior Art) Disk substrates, such as optical disk substrates such as video disks and compact disks, are usually manufactured by injection molding. In general, injection molding involves a fixed mold, and a method that is moved toward and away from the fixed mold.
A mold is used that includes a movable mold in which a predetermined stamper is set using inner and outer stamper holding members. By injecting and molding a predetermined resin material into a product cavity formed between the molds of such a mold, a disk base onto which the information of the stamper is transferred is manufactured.

By the way, in such a molding die for a disk base, since it is necessary to mold the disk base with good dimensional accuracy, it is necessary to accurately position the fixed mold and the movable mold when closing the mold where the product cavity is formed. There is a need to. Therefore, in such molds, tapered surfaces that correspond to each other are usually provided on the outer periphery of the fixed mold and the movable mold, and the molds are aligned by taper fitting of these tapered surfaces. is being carried out.

(Problem) However, in conventional molds for disk substrates, these tapered surfaces are provided in a fixed position relative to the cavity member forming the product cavity of each mold (fixed mold and movable mold). When the mold is closed, they are fitted to exhibit the core-insulating function, but when the mold is opened, they are not fitted and the core-insulating function is not achieved. When pressing (compressing) after injecting the resin material into the product cavity in (see item 1), the cavity member on the fixed mold side may come into contact with the inner circumferential surface of the outer stamper holding member at the peripheral edge of the cavity surface, causing it to snap. The life of the mold is shortened due to the galling phenomenon.
was there.

That is, a mold clamping device of an injection molding machine in which such a mold for a disk base is used generally includes a fixed platen 12 to which a fixed mold 10 is attached, as shown in FIG.
It has a structure in which the movable platen 16 and the movable mold 14 are horizontally opposed to each other. The movable platen 16 is guided by the guide rod 20 and moved toward and away from the fixed platen 12 in accordance with the advance and retreat of the ram 18 of the mold clamping cylinder, thereby opening and closing the mold 10.14. It is supposed to be done.

Therefore, the mold 10.1 in which the tapered surface is in the unfitted state
4, when the mold is opened, due to the existence of a sliding clearance between the movable platen 16 and the guide rod 20, as shown by symbol 20 in FIG. It is unavoidable that the mold 14 is slightly inclined toward the fixed mold 10 side, and due to the inclination of the movable mold 14, the cavity member on the fixed mold 10 side is tilted outward at the peripheral edge of the cavity surface. It is unavoidable that it comes into contact with the inner circumferential surface of the stamper holding member. In particular, the molds 10 and 1 are injected into the product cavity by the injection operation of the resin material.
In injection compression molding, the mold 4 is opened slightly, and after the resin material is injected, the movable mold 14 is pushed to the mold closing position and a clamping operation is performed. The post-injection clamping operation is performed while the tilted state of the movable mold 14 is maintained, that is, the peripheral edge of the cavity surface of the cavity member on the fixed mold 10 side is in contact with the inner peripheral surface of the outer stamper holding member. Since this tends to occur forcibly, a galling phenomenon has significantly occurred at the peripheral edge of the cavity surface of the cavity member on the side of the fixed mold 10 due to the contact.

In addition, in the conventional molding mold for disk substrates as described above, when used for injection compression molding, for the same reason as mentioned above, that is, the mold clamping operation after injecting the resin material into the product cavity is performed by a movable mold. Since the process is carried out with the mold 14 tilted, there is also the problem that the thickness of the disk base, which is the molded product, becomes thicker at the lower part of the mold (product cavity).

(Solution Means) Here, the present invention has been made against the background of the above-mentioned circumstances, and the gist thereof is to provide a fixed mold as described above, and a method for approaching the fixed mold. A predetermined stamper that is spaced apart includes a movable mold set by inner and outer stamper holding members, and information on the stamper is injected into a product cavity formed between the molds. By tapered fitting of mutually corresponding tapered surfaces provided on the outer peripheries of the fixed mold and the movable mold, which mold the disk base onto which is transferred,
In a disk base mold for centering these molds, the taper forming member on the fixed mold side or the movable mold side having the tapered surface is replaced with the taper forming member on the fixed mold side or the movable mold side. The cavity member is provided so as to be movable in parallel by a predetermined distance in the direction of approach and separation of the molds, and a biasing means is provided that biases the taper forming member in a direction in which it always projects from the cavity member. Between the mold closing position of the mold and the position where the movable mold moves a predetermined distance in the mold opening direction from the cough mold mold closing position, the tapered surfaces of the molds are in a fitted state in which the molds are centered. The reason is that it is maintained.

(Function/Effect) According to such a mold for a disk base, the taper surfaces for centering on the fixed mold and movable mold sides are aligned with the mold closing position of these molds and the movable mold at its mold closing position. The molds are held in a fitted state between the mold opening position and the position where the molds are moved a predetermined distance in the mold opening direction, and the molds are held in an aligned state during that time.
In the final stage of the mold closing operation of a mold, especially during the mold clamping operation after the injection operation of injection material into the product cavity in injection compression molding, the gap between the movable platen and the tie rod that guides the movable platen is Regardless of the presence of sliding clearance, the movable mold is held in a non-inclined state (parallel state) with respect to the fixed mold.

In other words, by using the mold for disk substrates according to the present invention, it is possible to effectively avoid the movable mold from being closed while being tilted relative to the fixed mold. This effectively prevents the cavity member from coming into contact with the inner circumferential surface of the outer stamper holding member at the peripheral edge of the cavity surface. Therefore, unlike the conventional molds mentioned above, it is possible to effectively prevent the galling phenomenon from occurring due to the contact between the molds when opening and closing the molds.Especially when used for injection compression molding, the mold This makes it possible to significantly improve the lifespan of.

Furthermore, when the mold according to the present invention is used for injection compression molding, the injection material can be injected while the movable mold is held parallel to the fixed mold, and the injection material can be injected in parallel to the fixed mold. Since the clamping operation can be performed after the injection operation while maintaining the state, the movable mold can be used instead of the movable mold due to the sliding clearance between the movable platen and the guide rod, unlike when using a conventional mold. There is no unevenness in the thickness of the molded product due to the inclination of the molded product, and therefore there is an advantage that a disk base of superior quality can be molded compared to the conventional method.

(Example) Hereinafter, in order to clarify the present invention more specifically,
One embodiment thereof will be described in detail based on the drawings. In addition,
Since the mold of this embodiment is used in a mold clamping device similar to that in which a conventional mold is used, the configuration of the mold clamping device will be explained with reference to FIG. 4.

First, FIG. 1 shows a sectional view of a main part of a mold for a disc substrate according to the present invention in a closed state.

There, 22 and 24 are a fixed mold and a movable mold constituting the mold of this example, respectively.
It is configured to include mirror blocks 30.32 as cavity members whose corresponding surfaces are mirror surfaces 26.28, and a mold body 34.36 that holds the mirror blocks 30.32. Then, when the mold bodies 34, 36 are brought into contact with each other at the outer portions of the respective mirror blocks 30, 32 when the mold is closed, a product cavity 38 with a predetermined gap is formed between the mirror blocks 30, 32. It has become. Note that the mirror surface 28 of the movable mirror block 32 has its inner and outer circumferential parts held by an inner stamper holding member (not shown) and an outer stamper holding member 40, respectively, as in the conventional mold, and a predetermined information pattern is formed on the mirror surface 28 of the movable mirror block 32. A donut-shaped stamper 42 is provided,
The information pattern of the stamper 42 is transferred to a disk substrate such as an optical disk substrate molded in the product cavity 38.

More specifically, each mold body 34.3 of the molds 22, 24
6 has concentric circular recesses 44 and 46 having approximately the same diameter and a predetermined depth, located on opposite sides thereof, and located on the opening periphery of the circular recesses 44 and 46. do,
The annular planes 4 of the molds 22 and 24 face each other in the same direction.
It has a score of 8.50. As shown in the figure, when the molds 22 and 24 are closed, the mold bodies 3
4.36 annular planes 48.50 are brought into abutment with each other.

On the other hand, the mirror blocks 30 and 32 are both approximately disk-shaped with a predetermined thickness, and the mold bodies 34 and 32 are respectively
It is disposed in a state housed in a circular recess 44,46. Then, the mold body 34°36 is annular plane 48.50
When the mold is closed, the mirror surfaces 26 and 28 facing each other, and even the mirror surface 2 on the fixed mold 22 side.
6 and a stamper 4 disposed on the mirror surface 28 on the movable mold 24 side.
2, a predetermined gap is formed between the two.

Further, each mirror block 30.32 is provided with an annular notch that defines the outer periphery of the mirror surface 26.28, and when the molds 22, 24 are closed, the notch An annular space is formed. The outer stamper holding member 40 is attached to the mirror block 32 on the movable side in such a manner that it is accommodated in the annular space, and an annular protrusion 56 formed on the inner circumferential surface of the outer stamper presser member 40 is attached to the movable mirror block 32 . is restrained to the mirror block 32. As shown in FIG. 1, when the mold is closed, the space between the mirror blocks 30. The product cavity 38 is thereby formed.

Here, the inner circumferential surface 58 of the annular protrusion 56 of the outer stamper holding member 40 that defines the outer circumference of the product cavity 38
and the annular stepped portion 60 surrounding the mirror surface 26 of the fixed side mirror block 30 are respectively tapered surfaces that correspond to each other, and as shown in FIG. When the mold is closed, a predetermined minute gap is formed between them. In addition, the molds 22, 2
4, when the mold is closed, there is a
A predetermined minute gap is formed. As a result, the outer stamper holding member 40 and the fixed mirror block 30 are prevented from interfering with each other, and gas in the product cavity 38 is vented through the gap during injection molding. There is.

Incidentally, such a mold requires high dimensional accuracy for the disk base, which is a molded product, and it is necessary to accurately position the fixed mold 22 and the movable mold 24 when the mold is closed. However, in the case where the centering state of the molds 22 and 24 is ensured only when the molds 22 and 24 are closed, as in the case of a mold that employs a conventional taper fitting mechanism, the mold 22 and 24
．． When the mold 24 is opened and closed, the peripheral edge of the mirror surface 26 of the fixed side mirror block 30 moves outward due to the inclination of the movable mold 24 based on the sliding clearance between the movable platen (16) and the guide rod (2°0). Inner peripheral surface 5 of stamper holding member 40
8 is unavoidable, especially during mold clamping (compression) after injection of the injection material in injection compression molding.
It is inevitable that a galling phenomenon will occur at the contact portion.

In addition, in injection compression molding, since the movable mold 24 tends to be held in an inclined state by the resin material injected into the product cavity 38, the above pressure is applied while the movable mold 24 is kept in an inclined state. When the tightening operation is performed, there is a problem in that the thickness of the molded disk base becomes uneven.

Therefore, in this embodiment, a tapered fitting mechanism as described below is provided at the outer periphery of the annular plane 48.50 of the mold body 34. The metal molds 22 and 24 are precisely aligned with the position where the molds 22 and 24 are opened by a predetermined dimension by the tapered fitting mechanism, and as a result, as described above, Efforts are being made to resolve the issue.

That is, in the mold of this embodiment, as shown in FIG.
4 is cut out in an annular shape so as to define the outer circumference of the annular plane 48, and the inner circumferential surface of the annular cutout is formed into a tapered surface 62 with a predetermined inclination angle, making it different from the conventional mold. Similarly, a tapered surface 62 is integrally formed with the mold body 34.

However, on the movable mold 24 side, as shown in FIG. 1, a tapered surface 64 that fits with the tapered surface 62 on the fixed mold 22 side is not directly formed on the mold body 36. First, it is formed as a taper forming member on the inner circumferential surface of an outer circumferential ring 66 provided separately from the mold body 36.

This outer ring 66 has a substantially cylindrical shape,
The distal end side (fixed mold 22 side) of the inner circumferential surface is a tapered surface 64 as described above, but the proximal end is a cylindrical surface 68, and as shown in the figure, the movable side mold Mold body 36
The cylindrical surface 68 is slidably fitted into a cylindrical surface 70 of a stepped portion provided on the outer periphery of the cylindrical surface. Here, both of the cylindrical surfaces 68 and 70 are machined with high precision, the sliding clearance between them is made as small as possible, and the outer ring 66 maintains high parallelism in the axial direction. It is designed so that it can be moved around.

Note that the outer ring 66 has a cylindrical surface 68 that is connected to the mold body 3.
It is formed to have the same length dimension as the cylindrical surface 70 of No. 6, and maintains the fitted state of the tapered surfaces 62.64 as shown in FIG. 1 when the mold 22.24 is closed. At the same time, the annular planes 48, 50 of the mold bodies 34, 36 are adapted to allow the butts to abut against each other.

The outer circumferential ring 66 has a plurality of through holes located at appropriate positions in the circumferential direction, each penetrating in the axial direction, and each opening on the tip side having a large diameter portion 72 having a large diameter over a predetermined length. A hole 74 is formed. On the other hand, the stepped surface 76 of the movable mold body 36 on which the outer ring 66 is seated has a stepped surface 76 having a predetermined depth, located at a portion corresponding to the formation portion of each through hole 74 of the outer ring 66. A bottom hole 78 is formed. As shown in FIG. 1, a sliding sleeve 82 having an outward flange portion 80 at one end in the axial direction is attached to the large diameter portion 72 for each through hole 74 of the outer ring 66. The sliding sleeves 82 are inserted into the bottomed holes 78 with bolts 84.
The outer ring 66 is attached to the mold body 36 by standing upright on the bottom of the mold body 36 . In this embodiment, the outer circumferential ring 6 can move in the axial direction by a distance α (usually about 1 to 211 degrees).

Further, as shown in FIG. 1, each of the bottomed holes 78
A compression coil spring 86 is disposed inside the sliding sleeve 82 in a state that the compression coil spring 86 is inserted into the sliding sleeve 82.
The second side is always biased. In this embodiment, the compression coil spring 86 constitutes a biasing means.

Note that the outward flange portion 80 of the sliding sleeve 82 that restricts the movement of the outer ring 66 toward the distal end side and the head of the bolt 84 that fixes the sliding sleeve 82 to the mold body 36 are not shown. The large diameter portion 7 of the through hole 74 is always
It is designed to be housed within 2.

According to such a taper fitting mechanism, the outer circumferential ring 66 is always fixed to the mold 22 by the biasing force of the compression coil spring 86.
It is urged toward the fixed mold 22 side and can protrude toward the fixed mold 22 by a distance α from the retracted position when the molds 22 and 24 are closed, so that as shown in FIG. , when the molds 22 and 24 are in the closed state, as shown in FIG.
4°36 (annular plane 48.50) is separated by a distance of 1iii:α. Even when the molds are opened, the tapered surfaces 62 and 64 of both molds 22 and 24 are held in a fitted state, and the metal The molds 22 and 24 are well secured.

Therefore, not only in normal injection molding in which resin material is injected into the product cavity 38 while the molds 22 and 24 are kept closed, but also in the case of injection molding as shown in FIGS. 2 and 3. The molds 22 and 24 are slightly opened by the injection operation of the injection material 88 into the product cavity 38, and after the injection of the resin material 88, the movable mold 24 is pushed out to the mold closing position and a clamping operation is performed. In injection compression molding where molding is performed, as shown in FIG. 2, the mold 22. is opened by injecting resin material 88 into the product cavity 38. ``If the mold opening distance of 24 is set to be less than α, regardless of the existence of sliding clearance between the movable platen (16) and the guide rod (20),
When the molds 22 and 24 are opened and closed, the mirror block 30 on the fixed side can be effectively prevented from coming into contact with the inner circumferential surface 58 of the outer stamper holding member 40 at the peripheral edge of the mirror surface 26, and therefore, It is possible to effectively prevent the galling phenomenon from occurring due to the contact between the molds 22 and 24 when they are opened and closed, as in conventional molds.

Furthermore, if the mold according to this embodiment is used for injection compression molding, as shown in FIG.
The injection operation can be performed at the same time as the clamping operation can be performed after the injection operation while maintaining the parallel state, so the movable platen 16 and the guide rod 20 can be This prevents unevenness in the thickness of the disk substrate due to the inclination of the movable mold 24 due to the sliding clearance between the two, and therefore the quality of the disk substrate can be significantly improved compared to the conventional method.

Incidentally, when a compact disc with a diameter of 1201 m is molded by injection compression molding using a conventional mold, the upper and lower ends of the compact disc (product cavity 3
There was a thickness unevenness of about 20 μm in the parts corresponding to the upper and lower ends of 8), but in the molded product using the mold of this example, the difference was almost 0", and there was almost no difference in thickness. It is recognized that no thickness unevenness occurs.

Although one embodiment of the present invention has been described in detail above, this is a literal illustration, and it goes without saying that the present invention should not be interpreted as being limited to this specific example.

For example, in the embodiment described above, the outer circumferential ring 66 as a taper forming member was provided on the movable mold 24 side, but it is also possible to provide such an outer circumferential ring on the fixed mold 22 side.

Further, in the above embodiment, an example was described in which the present invention was applicable to a mold in which the outer circumference of the product cavity 38 was defined by the outer stamper holding member 40. The present invention can also be applied to a mold in which the cavity is defined by a cavity defining member provided on the fixed mold 22 side.

In addition, although not listed, various modifications may be made without departing from the spirit of the present invention.

It goes without saying that the present invention can be implemented with modifications, improvements, etc.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of essential parts of a mold according to the present invention in a closed state. 2 and 3 are cross-sectional views corresponding to FIG. 1 showing mutually different operating modes when the mold shown in FIG. 1 is used for injection compression molding. Figure 4 shows
FIG. 2 is an explanatory diagram schematically showing a conventional mold clamping device. 12: Fixed plate 16: Movable plate 20 guide rod 22: Fixed mold 24: Movable mold 26. 28: Mirror surface 30. 32: Mirror block (cavity member) 34. 36j mold body 38: Product cavity 40: Outside Stand bar holding member

Claims (1)

[Claims] The movable mold includes a fixed mold, and a movable mold in which a predetermined stamper is set by inner and outer stamper holding members, the mold being moved toward and away from the fixed mold, mutually corresponding tapered surfaces provided on the outer peripheries of the fixed mold and the movable mold, which mold a disk base onto which the information of the stamper is transferred by injecting a predetermined resin material into the product cavity to be formed; In the disk base mold, the molds are aligned by taper fitting, and the taper forming member on the fixed mold side or the movable mold side having the tapered surface is connected to the fixed mold side. Alternatively, a biasing means is provided for the cavity member on the movable mold side so as to be movable in parallel by a predetermined distance in the direction of approach and separation of the molds, and that biases the taper forming member in a direction to always protrude from the cavity member. between the mold closing position of the mold and the position where the movable mold moves a predetermined distance from the mold closing position in the mold opening direction, the tapered surfaces of the molds protect the molds. A mold for a disk base, characterized in that it is held in a core-fitting state.