JP2003154558A - Disk molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely leave a sprue section in a second die assembly when the mold is opened. SOLUTION: This disk molding die has a sprue bush 24, a cut punch 48, and an ejector pin 71. In this case, the sprue bush 24 constitutes a first die assembly. Also, for the sprue bush 24, a sprue 26 through which a molding material passes is formed, and at the front end of which, a die 28 is formed. The cup punch 48 constitutes a second die assembly, and is longitudinally movably arranged while being confronted with the sprue bush 24. Also, the cut punch is equipped with a holding section 65, with an undercut formed at its front end. The ejector pin 71 is longitudinally movably arranged while making the front end face to the holding section 65. Also, the ejector pin 71 is equipped with a notched section 72, on which an undercut is formed on the front end. In this case, even when the molding material which has entered the holding section 65 and the notched section 72 is not sufficiently cooled, a holding force to hold the sprue section can be sufficiently generated by the undercuts which are formed on the holding section 65 and the notched section 72.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk molding die.

[0002]

2. Description of the Related Art Conventionally, in an injection molding machine for molding a disk substrate, resin melted in a heating cylinder is filled in a cavity space in a disk molding die, and the cavity space is filled with the resin. The disk substrate is obtained by cooling inside and solidifying.

To this end, the injection molding machine is a disk molding comprising a stationary mold assembly as a first mold assembly and a movable mold assembly as a second mold assembly. A mold for injection, an injection device for filling the cavity space with the resin, and a mold clamping device for bringing the movable mold assembly into and out of contact with the fixed mold assembly.
Then, the mold side on the movable side is moved back and forth by the mold clamping device to perform mold closing, mold clamping and mold opening of the disk molding mold, and at the time of mold closing and mold clamping, the fixed side mold assembly. A cavity space is formed between the disk plate and the disk plate of the movable mold assembly.

Further, the injection device is provided with a heating cylinder, an injection nozzle attached to the front end of the heating cylinder, and a screw rotatably and reciprocally arranged in the heating cylinder.

Then, in the measuring step, the screw is rotated, the resin is melted and stored in front of the screw, and the screw is retracted accordingly, and during this, the mold of the disk molding die is closed. And the mold clamping is performed. Subsequently, in the injection step, the screw is moved forward, and the resin stored in front of the screw is injected from the injection nozzle to fill the cavity space. Then, in the cooling step, the resin in the cavity space is cooled, punching is performed, and the disk substrate is molded. Subsequently, the mold is opened and the disc substrate is taken out.

FIG. 2 is a sectional view showing a main part of a conventional disk molding die.

In the figure, 24 is a sprue bush arranged on the fixed side, 26 is a sprue formed by penetrating the sprue bush 24, and 28 is a cavity space at the front end (lower end in the figure) of the sprue bush 24. It is a die composed of a concave portion formed so as to face C.
Further, 48 is disposed so as to face the sprue bush 24 and is movable forward and backward (movable in the vertical direction in the drawing) on the movable side, and has a front end (upper end in the drawing) corresponding to the die 28. The cut punch 62 is a cylindrical eject tab that is arranged around the cut punch 48 so as to be able to move back and forth. The front end of the cut punch 48 enters the die 28 and the resin in the cavity space C Drilling is performed.

By the way, in the injection step, the resin injected from the injection nozzle (not shown) is used as the sprue 26.
And is filled into the cavity space C, and in the cooling step, the resin in the cavity space C is cooled to form a substrate prototype, and the resin in the sprue 26 is also cooled to form a sprue portion. . Then, the cut punch 48 is moved forward (moved upward in the figure),
A disk substrate is formed as the substrate master is punched. Then, when the mold opening is started, the cut punch 48 has a holding portion 65 formed of a concave portion at the front end so that both the disc substrate and the sprue portion remain on the movable side. The holding portion 65 has a cross-sectional area that increases from the front end surface (upper end surface in the drawing) of the cut punch 48 to the rear (lower side in the drawing) (as the holding portion 65 becomes deeper) to form an undercut, and the mold opening is prevented. As it is started, the sprue portion is held together with the resin solidified in the holding portion 65.

A through hole 66 penetrating the cut punch 48 is formed rearward from the holding portion 65, and the ejector pin 67 is movable back and forth with the front end facing the holding portion 65 in the through hole 66. It is arranged. Further, a projecting drive unit (not shown) is disposed behind the ejector tab 62 and the ejector pin 67.

Therefore, when the ejecting tabs 62 and the ejector pins 67 are moved forward by driving the projecting drive portion at a predetermined timing after the mold opening is started, the ejector tabs 62 and the ejector pins 67 are held by the movable side mold assembly. The disc substrate and the sprue portion are projected.

[0011]

However, in the above-described conventional disk molding die, if the resin that has entered the holding portion 65 is not sufficiently cooled, the sprue is formed even though an undercut is formed. The holding force for holding the portion cannot be sufficiently generated, and the sprue portion cannot be surely left on the movable side die assembly when the die is opened.

The present invention solves the above-mentioned problems of the conventional disk molding die, and provides a disk molding die capable of reliably leaving the sprue portion in the second mold assembly when the mold is opened. The purpose is to do.

[0013]

Therefore, in the mold for molding a disk of the present invention, a sprue through which the molding material passes, which constitutes the first mold assembly, is formed, and a die is formed at the front end of the sprue. A sprue bush formed with a second
Of the die assembly, which is arranged to face the sprue bush so that it can move forward and backward, and has a holding portion having a holding portion with an undercut formed at the front end, and can move forward and backward with the front end facing the holding portion. And an ejector pin having a notch formed with an undercut at the front end.

In another disk molding die of the present invention, the notch is formed over almost half of the cross-sectional area of the ejector pin.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an essential part of a disk molding die according to an embodiment of the present invention, and FIG. 3 is a sectional view of a disk molding die according to an embodiment of the present invention.

In the figure, reference numeral 12 is a fixed-side mold assembly as a first mold assembly, which is attached to a fixed platen (not shown) via a mounting plate 13 by bolts (not shown). Reference numeral 12 denotes a base plate 15 as a first support plate, and the base plate 15
A disk plate 16 as a first mirror surface plate attached by a bolt (not shown), and is disposed in the mounting plate 13 so as to face the fixed platen side, and the mold assembly 1
A locating ring 23 that positions 2 with respect to the fixed platen, and a sprue bush 24 disposed adjacent to the locating ring 23 are provided. A cavity space C is provided at the front end (left end in FIG. 3) of the sprue bush 24.
A die 28 composed of a concave portion is formed to face the
A sprue 26 is formed which is in communication with 8 and allows a resin, which is a molding material, injected from an injection nozzle of an injection device (not shown) to pass therethrough. The injection device includes a heating cylinder (not shown), an injection nozzle attached to the front end of the heating cylinder, and a screw rotatably and reciprocally arranged in the heating cylinder.

A stamper (not shown) for forming irregularities on the information surface of the disc substrate is attached to the disc plate 16 and the front half portion (left half portion in FIG. 3) of the sprue bush 24 is radially outside. On one side, a stamper pressing bush 14 for pressing the inner peripheral edge of the stamper is arranged. It should be noted that the mold assembly 12 is also provided with an air brush or the like (not shown).

An annular abutment ring 18 is attached to the outer peripheral edge of the disk plate 16 by a bolt b1, and an annular first guide ring 19 is radially outward from the disk plate 16 and the abutment ring 18. Are attached to the base plate 15.

On the other hand, 32 is a movable side mold assembly as a second mold assembly, which is attached to a movable platen (not shown) by bolts (not shown). The mold assembly 32 includes the base plate 35, Base plate 35
An intermediate plate 40 as a second support plate attached to the intermediate plate 40 by a bolt b2, a disk plate 36 as a second mirror plate attached to the intermediate plate 40 by a bolt b3, and a movable platen in the base plate 35. And a guide member 44 attached to the intermediate plate 40 by a bolt b4, and a cut punch 4 arranged so as to face the sprue bush 24 and move back and forth (movement in the left-right direction in FIG. 3).
8, the cutting punch 48 has a shape in which the front end (the right end in FIG. 3) corresponds to the die 28.

At the outer peripheral edge of the disc plate 36, the disc plate 36 is movable with respect to the disc plate 36, and
An annular cavity ring 3 facing the abutment ring 18
7 is disposed, and an annular second guide ring 38 is attached to the intermediate plate 40 so as to face the first guide ring 19 radially outward of the disc plate 36 and the cavity ring 37. The cavity ring 37 is attached to the rod 41 by a bolt b5 and is movably arranged with respect to the intermediate plate 40 via the rod 41. A spring 63 as a biasing member for biasing the cavity ring 37 toward the fixed side is provided at the rear end (the left end in FIG. 3) of the rod 41.
Is provided. Further, 39 is a cavity ring retainer attached to the second guide ring 38 by a bolt (not shown), and the cavity ring retainer 39 is engaged with the outer peripheral edge of the cavity ring 37. The cavity ring 37 is projected from the front end surface (right end surface in FIG. 3) of the disk plate 36, and the inner peripheral surface of the cavity ring 37 forms the outer peripheral edge of the disc substrate (not shown).

A flange 51 formed integrally with the cut punch 48 is provided in the guide member 44.
Is arranged so as to be movable back and forth along the rear end 5 of the flange 51.
1a is received by the guide member 44. A cut punch return spring 52 is arranged in front of the flange 51 (right side in FIG. 3), and the flange 51 is urged rearward (left side in FIG. 3) by the cut punch return spring 52. . A drive cylinder (not shown) is disposed behind the cut punch 48.

The mold assemblies 12 and 32 form a disk molding mold, and a mold clamping device (not shown) is provided to bring the mold assembly 32 into and out of contact with the mold assembly 12. To be done. By driving the mold clamping cylinder of the mold clamping device and advancing and retracting the mold assembly 32, it is possible to perform mold closing, mold clamping and mold opening of the disk molding mold, and the disc plate at the time of mold clamping. The cavity space C is formed between 16 and 36.

When the flange 51 is moved forward (moved to the right in FIG. 3) by driving the drive cylinder during mold clamping, the cut punch 48 is advanced and enters the die 28. As a result, the resin in the cavity space C can be perforated.
An ejector tab 62 for projecting the disk substrate is arranged movably outward in the radial direction in the front half portion (right half portion in FIG. 3) of the cut punch 48.
An air probe 47 for blasting compressed air to the disc substrate to release the disc substrate from the disc plate 36 is disposed radially outward of the eject tab bush 62.

First and second temperature control channels 93 and 94 are formed in the disk plates 16 and 36, respectively.
By supplying a temperature control medium such as water, oil, or air to the second temperature control flow paths 93, 94, the disc plate 16,
36 is cooled.

Then, in the measuring step, the screw is rotated, the resin is melted and stored in front of the screw, and the screw is retracted accordingly, and during this, the mold of the disk molding die is closed. And the mold clamping is performed. Subsequently, in the injection step, the screw is advanced, the resin stored in front of the screw is injected from the injection nozzle, and the cavity space C is filled. Then, in the cooling step, the resin in the cavity space C is cooled, punching is performed, and the disk substrate is molded. Subsequently, the mold is opened and the disc substrate is taken out.

In the injection step, the resin injected from the injection nozzle passes through the sprue 26 and is filled in the cavity space C, and in the cooling step, the resin in the cavity space C is cooled to form a substrate prototype. At the same time, the resin in the sprue 26 is also cooled, and a sprue portion (not shown) is formed. Subsequently, the cut punch 48 is advanced, and the disk substrate is formed as the substrate master is punched. Then, the cut punch 48 has a holding portion 65 formed of a concave portion at the front end so that both the disc substrate and the sprue portion remain in the die assembly 32 when the die opening is started. The holding portion 65 is rearward (downward in FIG. 1) from the front end surface (upper end surface in FIG. 1) of the cut punch 48.
Over time (as the holding portion 65 becomes deeper), the cross-sectional area is widened to form an undercut, and as the mold opening is started, the sprue portion is held together with the resin solidified in the holding portion 65.

A through hole 66 is formed from the holding portion 65 toward the rear so as to penetrate the cut punch 48, and the ejector pin 71 is moved back and forth with the front end facing the holding portion 65 in the through hole 66 (see FIG. 1 is movable in the vertical direction). Further, a projecting drive unit (not shown) is disposed behind the ejector tab 62 and the ejector pin 71.

Therefore, when the ejecting tabs 62 and the ejector pins 71 are moved forward (moved upward in FIG. 1) by driving the projecting drive portion at a predetermined timing after the mold opening is started, the mold assembly Three-dimensional
The disc substrate and the sprue portion held by 2 are projected.

If the resin that has entered the holding portion 65 is not sufficiently cooled, the holding force for holding the sprue portion cannot be sufficiently generated even though the undercut is formed, and the mold It becomes impossible to reliably leave the sprue portion on the mold assembly 32 when opening.

Therefore, the ejector pin 71 is provided at its front end with a notch 72 in which an undercut is formed at a predetermined depth over almost half of the cross-sectional area.
And a locking portion 73 is formed on the remaining portion of the ejector pin 71. The notch 72 has a wider cross-sectional area from the front end surface of the ejector pin 71 toward the rear (as the notch 72 becomes deeper), and as the mold opening is started, the inside of the holding portion 65 and the notch 72 is increased. The sprue portion is held by the resin solidified in. Further, the ejector pin 71 is placed in the retracted limit position during the injection process and the cooling process, and is advanced at the timing when the ejector tab 62 is advanced after the mold opening is started.

Therefore, even if the resin that has entered the holding portion 65 and the notch 72 is not sufficiently cooled, the holding portion 65
And the undercut formed in the cutout 72,
Since sufficient holding force for holding the sprue portion can be generated, the sprue portion can be reliably left in the mold assembly 32 when the mold is opened.

When the eject tab bush 62 and the ejector pin 71 are moved forward, the locking portion 73
Protrudes from the through-hole 66 and enters the holding portion 65. With this, the resin solidifies in the notch 72 and the resin constrained by the undercut is not constrained but is easily deformed. Therefore, by advancing the ejector tabs 62 and the ejector pins 71, the sprue portion held by the mold assembly 32 can be easily ejected.

Further, the resin remaining at the front end of the injection nozzle in the previous molding cycle is cooled and solidified, and when the solidified resin enters the cavity C as foreign matter in the next molding cycle, the quality of the disk substrate is deteriorated. However, when the foreign matter passes through the sprue 26 and enters the cavity C with the injection, the foreign matter can be accumulated in the notch 72. Therefore, foreign matter does not enter the cavity C, so that the quality of the disk substrate can be improved.

The present invention is not limited to the above-mentioned embodiments, but can be variously modified within the scope of the present invention, and they are not excluded from the scope of the present invention.

[0036]

As described in detail above, according to the present invention, in the disk molding die, the first die assembly is formed, and the sprue through which the molding material passes is formed.
A sprue bush having a die formed at the front end of the sprue and a second mold assembly, and a holding portion that is arranged so as to face the sprue bush so as to be able to move back and forth, and has an undercut formed at the front end. A cut punch provided with the ejector pin; and an ejector pin provided with a notch portion having an undercut formed at the front end, the ejector pin having a front end facing the holding portion and being capable of advancing and retracting.

In this case, even if the molding material that has entered the holding portion and the notch is not sufficiently cooled, the undercut formed in the holding portion and the notch sufficiently generates a holding force for holding the sprue portion. Therefore, the sprue portion can be surely left in the second mold assembly when the mold is opened.

Then, when the cut punch and the ejector pin are advanced, the locking portion adjacent to the cutout portion enters into the holding portion, which is solidified in the cutout portion and restrained by the undercut. Not only is the molding material that has been used entered into the holding part and is not restrained,
Since it is easily deformed, the sprue portion held by the second mold assembly can be easily ejected by advancing the cut punch and the ejector pin.

Further, the molding material remaining at the front end of the injection nozzle in the previous molding cycle is cooled and solidified, and when the solidified molding material enters the cavity space as foreign matter in the next molding cycle, the quality of the disk substrate is deteriorated. However, the foreign matter can pass through the sprue as it is ejected and accumulate in the notch when entering the cavity space. Therefore, foreign matter does not enter the cavity space, so that the quality of the disk substrate can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a main part of a disk molding die according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a main part of a conventional disk molding die.

FIG. 3 is a cross-sectional view of a disk molding die according to the embodiment of the present invention.

[Explanation of symbols]

12, 32 mold assembly 24 sprue bush 26 sprue 28 dies 48 cut punch 65 holding part 71 ejector pin 72 Notch

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasushi Odabe             1 731 Naganumahara-cho, Inage-ku, Chiba-shi, Chiba               Sumitomo Heavy Industries, Ltd. Chiba Works F-term (reference) 4F202 AH38 AH79 CA11 CB01 CK02                       CM09 CM11 CM18

Claims (2)

[Claims] 1. A sprue bush which comprises (a) a first mold assembly, a sprue through which a molding material passes, and a die formed at a front end of the sprue; and (b) a second metal mold. A mold punch, which is provided with a holding portion that is arranged to face the sprue bush so as to move forward and backward and has an undercut formed at the front end, and (c) moves forward and backward with the front end facing the holding portion. A metal mold for disk molding, comprising an ejector pin which is freely arranged and has a notch formed with an undercut at a front end. 2. The disk molding die according to claim 1, wherein the cutout portion is formed over substantially half of a cross-sectional area of the ejector pin.