JPH0460414B2 - - Google Patents

Description

Detailed Description of the Invention (Technical Field) The present invention relates to a disk molding die used for molding disks such as optical disks and magnetic disks.
In particular, it relates to technology that enables shortening of molding cycles.

(Prior art and its problems) Disks such as optical disks and magnetic disks are usually manufactured by injection molding. and,
In general, the injection molding requires a sprue bush that is supported movably in the axial direction through a through hole in a stationary cavity member formed concentrically with the disc molding cavity, and a a punch cutter located at and movable in the axial direction while penetrating the movable cavity member; The punch cutter is provided with an ejector pin that punches out the center hole of the molded disk by protruding toward the sprue bush, and the ejector pin punches out the center hole of the disk into the movable cavity member. A disc mold is used which allows the disc to be released from the mold.

By the way, in such a disk mold, a large-volume sprue resin reservoir is formed at the tip of the ejector pin, and the key to improving the molding cycle is how quickly the resin in the sprue resin reservoir can be cooled and solidified. However, if the area around the sprue resin pool is cooled too quickly to shorten the molding cycle,
Because the resin in the sprue resin reservoir is thick, air bubbles are generated inside the resin (sprue), and the air bubbles generated inside the sprue cause the sprue to break, resulting in so-called sprue breakage. There was a problem. For this reason, in the past, it was necessary to cool the area around the sprue resin reservoir over a relatively long period of time, which was a major factor that hindered shortening of the molding cycle.

(Solution Means) The present invention has been made against the background of the above-mentioned circumstances, and its gist is that the above-mentioned sprue bush, punch cutter,
In a disk molding die equipped with an ejector pin, the ejector pin is movable in the axial direction while passing through the ejector pin in the axial direction. A cooling pin that can protrude is provided, and the tip of the cooling pin is inserted into a sprue resin reservoir formed at the tip of the ejector pin.

(Function/Effect) In such a disc mold, the tip of the cooling pin is pushed into the sprue resin reservoir, so the thickness of the resin in the sprue resin reservoir becomes thinner accordingly. This makes it possible to enhance the cooling effect on the resin in the sprue resin reservoir without generating air bubbles inside the resin (sprue) that solidifies within the sprue resin reservoir. Therefore, the cooling time of the resin in the sprue resin reservoir can be shortened without causing sprue breakage, and therefore the disk molding cycle can be improved accordingly.

Furthermore, in the disk mold according to the present invention, since the cooling pin is movable relative to the ejector pin in the axial direction, it is possible to separate the central hole punched portion of the disk from the movable cavity member. By protruding the ejector pin, the resin in the center hole punched portion and the tip of the cooling pin can be separated from each other, and the adhesion force of the resin in the center hole punched portion to the ejector pin can be reduced accordingly. It can be done. Therefore, when the resin in the punched center hole part is to be sucked and removed by a suction device, the resin in the center hole punched part can be easily separated from the ejector pin and can be reliably removed. There is.

Incidentally, when the cooling pin or the cooling protrusion that replaces it is provided integrally with the ejector pin, the resin in the central hole punched part is firmly attached to the protrusion (cooling protrusion) of the cooling pin due to the pressure of the resin. Because it is fixed to the ejector pin in the state,
Depending on the suction force of the suction device, it may be difficult to separate the center hole punched portion from the ejector pin, and there is a possibility that the center hole punched portion may not be able to be removed.

(Example) Hereinafter, in order to clarify the present invention more specifically, one example thereof will be described in detail based on the drawings.

First, in FIG. 1, reference numeral 10 denotes a stationary cavity member that forms a disc-shaped disc molded cavity (hereinafter simply referred to as cavity) 14 together with a movable cavity part 12. Recess 20 formed in the center
It is fixedly installed. fixed side cavity member 10,
A through hole 22 is formed in the back plate 16 and the stationary plate 18 so as to pass through the back plate 16 and the fixed plate 18 concentrically with the cavity 14, and a sprue bush is installed in the through hole 22 so as to be movable a predetermined distance in the axial direction. 24 is inserted. A predetermined resin material is injected into the cavity 14 through the sprue bush 24 from an injection device (not shown).

The sprue bush 24 is fitted into the through hole 22 via a sleeve member 28 that forms a cooling water passage 26 between the sprue bush 24 and the outer surface of the sprue bush 24 . Further, in FIG. 1, 30 and 32 are cooling water passages formed in the fixed cavity member 10 and the movable cavity member 12, respectively, and 34 and 36 are cavity surfaces of the movable cavity member 12, respectively. Stamper 3 placed in
This stamper holder is fixedly attached to the fixed cavity member 10 and the movable cavity member 12 in order to press down the outer peripheral portion of the stamper 8.

On the other hand, a movable cavity member 12 forming a cavity 14 together with a fixed cavity member 10
is fixed in a recess 44 formed in the center of the movable first member 42 via the back plate 40, and further includes a movable second member 46 and a movable third member 4.
It is fixed to the movable platen 50 via 8. When the movable platen 50 is moved in the horizontal direction in the figure by a mold clamping cylinder (not shown), the movable cavity member 12 forms a cavity 14 with the stationary cavity member 10. It is configured to be able to move integrally with the movable platen 50 between the mold opening position and the mold opening position where the cavity 14 is opened.

The movable cavity member 12 and the back plate 40 include
A through hole 52 is formed concentrically with the through hole 22 and extends through them.
An inner stamper holder 54 is disposed so as to be fitted into the stamper holder 54 . The inner peripheral portion of the stamper 38 is fixed to the movable cavity member 12 by the inner stamper holder 54. The inner stamper holder 54 is screwed onto a screw member 58 that is rotated by a handle member 56, and can be moved in the axial direction by rotating the handle member 56. . This allows the inner peripheral portion of the stamper 38 to be attached to and removed from the movable cavity member 12.

A sleeve member 60 fixedly supported by the fixed first member 42 is fitted into the inner peripheral surface of the inner stamper holder 54, and the sleeve member 60 is fitted onto the inner peripheral surface of the sleeve member 60. A disk product 61, which will be described later, is moved to the movable cavity member 12 in a state where it can be moved a predetermined distance in the axial direction relative to the member 60.
A protruding collar 62 is provided for detaching from the holder.

Here, the protruding collar 62 has its base end fixed to the intermediate plate 64, and the protruding collar 62 has its base end fixed to the intermediate plate 64.
It is designed so that it can be moved integrally with 4. Further, the intermediate plate 64 is operatively connected to the protruding action plate 70 via a connecting pin 66 and a sleeve member 68 disposed on the outer circumferential surface of the intermediate plate 64. It is designed to be moved intermittently in the direction of the heart.
Further, the protruding action plate 70 is normally held at the retracting limit position shown in the drawing by the coil spring 72, but when the movable platen 50 is moved back a certain distance in the right direction in the drawing, the protruding action plate 70 is activated. When the force input bolt 74 is brought into contact with an ejector bolt (not shown), it is thereafter moved forward relative to the movable platen 50 as the movable platen 50 moves backward.

When the movable platen 50 is moved backward for a certain distance or more to open the mold, the protruding action plate 70 is moved forward relative to the movable platen 50.
0 is advanced a certain distance or more, the sleeve member 68 comes into contact with the intermediate plate 64, and the intermediate plate 64, that is, the protruding collar 62 fixed to this intermediate plate 64,
is adapted to be moved forward relative to the movable cavity member 12. By the forward movement of the protruding collar 62, a disk product 61, which will be described later, is separated from the movable cavity member 12 (suntaper 38).

Note that the intermediate plate 64 is housed in a space 76 formed in the second movable member 46, and its forward limit position and backward limit position correspond to the first movable member 42 and the third movable member 48, respectively. It has come to be defined by Further, the protruding action plate 70 is housed in a recess 78 formed in the movable platen 50, and is reciprocated within the range where it comes into contact with the bottom surface of the recess 78 and the movable third member 48. It's getting old.

Further, a punch cutter 80 is slidably fitted on the inner circumferential surface of the protruding collar 62 coaxially with the sprue bush 24, and is cut by an air cylinder 82 provided in the movable platen 50. It is designed to be able to protrude a predetermined distance toward the sprue bush 24 side.

From the state shown in Fig. 1, the air cylinder 8
When the second piston 84 is operated to protrude leftward in the drawing, the punch cutter 80 causes the piston 84 to protrude toward the sprue bushing 24 via the connecting plate 88 housed in the cavity 86 of the movable third member 48. It has become possible to protrude only in quantity.
As a result, the center hole 90 of the disk molded product formed in the cavity 14 is punched out, and the disk molded product is connected to the center hole punched portion 92 punched by the punch cutter 80 and the disk molded product. It is designed to be separated into a product 61 (see Fig. 3).

The punch cutter 80 is slidably fitted to the protruding collar 62 via a sleeve member 96 that forms a cooling water passage 94 between the punch cutter 80 and the outer surface of the punch cutter 80, and is moved forward and backward together with the sleeve member 96. It's getting old. Therefore, a central hole 90 corresponding to the outer diameter of this sleeve member 96 is formed in the disk product 61. Further, the sprue bush 24 and the sleeve member 28 fitted to its outer circumferential surface are moved backward in the left direction in the figure as the punch cutter 80 and the sleeve member 96 fitted to its outer circumference move forward. becomes.

Furthermore, a longitudinal cylindrical ejector pin 98 is disposed on the inner circumferential surface of the punch cutter 80 so as to be able to slide through it in the axial direction. This ejector pin 98 is fixed to the protruding action plate 70 at its base end on the side of the movable platen 50, and during injection molding in which the ejector action plate 70 is held at its retraction limit position, the ejector pin 98 is shown in detail in FIG. As shown, the tip thereof is held in a position that is retreated by a predetermined distance toward the movable plate 50 from the tip of the punch cutter 80. However, as described above, when the protruding action plate 70 is moved forward relative to the movable plate 50 due to the backward movement of the movable plate 50, the punch cutter 80
As shown in FIG.
0). In addition,
As is clear from this, the operation of ejecting the central hole punched portion 92 by the ejector pin 98;
The operation of ejecting the disk product 61 by the ejecting collar 62 is performed in stages.

In this embodiment, as shown in FIG. 1, the inner hole 1 of the ejector pin 98 is
00, a metal cooling pin 102 fixed to the movable platen 50 is slidably fitted at the base end. During injection molding in which the ejector pin 98 is held at its retraction limit position, the approximately conical tapered tip 104 of the cooling pin 102 is moved a predetermined distance (here, punch cutter) from the tip surface of the ejector pin 98. 80).

In other words, the resin material is attached to the sprue bush 24.
During injection molding in which the resin is injected into the cavity 14 through the cooling pin 98, the tip 104 of the cooling pin 102 is inserted into a sprue resin reservoir 106 formed at the tip side of the ejector pin 98. When the ejector pin 98 operates to eject the central hole punched portion 92, the cooling pin 102 is moved back relative to the ejector pin 98 in the right direction in FIG. In addition, in FIG. 2, 108 is an annular groove for pulling out the center hole punching part 92 toward the punch cutter 80 side when opening the mold.

Therefore, according to such a molding machine, the tip portion 104 of the cooling pin 102 is placed in the sprue resin reservoir 106 formed at the tip side portion of the ejector pin 98.
As it is becoming more and more likely that
The thickness of the resin that is injected and filled into the sprue resin reservoir 106 is correspondingly thinner, and therefore the sprue resin reservoir 106 can be filled without creating air bubbles inside the resin (sprue) that solidifies within the sprue resin reservoir 106. The cooling effect on the resin inside 106 can be enhanced. And therefore,
The cooling time of the resin in the sprue resin reservoir 106 can be shortened without causing sprue breakage due to such air bubbles, and therefore the disk molding cycle can be improved accordingly. .

In addition, in the mold of this embodiment, the central hole punched portion 9 of the disc molded product by the ejector pin 98
2, the cooling pin 104 is retracted relative to the ejector pin 98, so that the ejector pin 98 causes the center hole punched portion 92 to eject. As shown, the resin in the central hole punched portion 92 and the tip 104 of the cooling pin 102 can be separated. Therefore, the adhesion force of the resin in the center hole punched portion 92 to the ejector pin 98 can be reduced by that amount, and therefore, the resin in the center hole punched portion 92 can be reliably removed by a suction device (not shown). can be absorbed and eliminated.

Although one embodiment of the present invention has been described in detail above,
This is just an example, and it goes without saying that the present invention is not limited to these specific examples, and can be practiced with various changes, modifications, improvements, etc. without departing from the spirit thereof. .

[Brief explanation of the drawing]

FIG. 1 is an explanatory sectional view showing an example of a disk mold according to the present invention, and FIG. 2 is an enlarged view of the main part thereof. FIG. 3 is an explanatory cross-sectional view for explaining the operating state in which the ejector pin in the mold shown in FIG. 1 is ejected. 10: Fixed side cavity member, 12: Movable side cavity member, 14: Disc molding cavity,
18: Fixed plate, 24: Sprue bush, 26,
94: Cooling water passage, 50: Movable plate, 61: Disk product, 62: Projection collar, 70: Projection action plate, 80: Punch cutter, 82: Air cylinder, 92: Center hole punched part, 98: Ejector pin, 102: Cooling Pin, 104: Tip (of cooling pin), 106: Sprue resin reservoir.

Claims (1)

[Scope of Claims] 1. A sprue bushing supported movably in the axial direction through a through hole of a stationary cavity member formed concentrically with the disk molding cavity;
a punch cutter positioned coaxially with the sprue bushing and movable in the axial direction while passing through the movable cavity member; and an ejector pin movably disposed on the sprue bush, the punch cutter punches out the center hole of the formed disk by protruding toward the sprue bushing, and the ejector pin punches out the center hole of the disk. In a disk molding die whose portion is detachable from the movable cavity member, an end face of the ejector pin is movable in the axial direction relative to the ejector pin while passing through the ejector pin in the axial direction. A cooling pin that can protrude by a predetermined distance is disposed on the sprue bushing side, and the tip of the cooling pin is inserted into a sprue resin reservoir formed at the tip of the ejector pin. Disc mold. 2. The mold according to claim 1, wherein the tip of the cooling pin has a tapered shape.