JPH0521053B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an optical disk molding die having means for accurately punching out a center hole of an optical disk replica within the mold during a molding cycle.

Structure of the conventional example and its problems As shown in Fig. 1, a conventional optical disk molding die has a method for punching out the center hole of the optical disk replica within the mold during the molding cycle.
After molding, the parting surface 5 of the mold is closed using a cam or the like, and the contact surface 6 of the fixed side mounting plate 8 and the fixed side mold plate 15 is opened by the stroke of the gap 7, and at the same time, the movable side air cylinder 4 is closed. By pushing the punch 1 fixed to the ejector plate 2 toward the spool bush 12 by thrust, the resin 10 at the center of the mold cavity was punched out to form a center hole.

In such a configuration, when punching the center hole, the molding machine is in the mold opening state, and the mold is connected to the fixed side mounting plate 8 fixed to the injection cylinder side platen of the molding machine, and the mold of the molding machine. A movable mold 25 fixed to the tightening platen, a fixed mold plate 15 with the parting surface 5 in contact with the movable mold 25 via the guide pins 22 and guide blocks 23 and 24; separated into For this reason, punch 1 and spool bush 1 were concentric in the mold clamping state.
The central axes 22 and 23 of 2 are the mold opening accuracy of the molding machine,
Misalignment occurs due to the weight of the mold, the fitting clearance between the guide pin 22 and the guide blocks 23, 24, etc., and due to this, the fit between the punch head diameter portion 20 and the cutting edge diameter portion 21 during punching of the center hole may occur. This caused a deviation in the matching clearance, resulting in a decrease in the accuracy of the replica center hole when punching the center hole. Also, an air cylinder 4 which is a forward driving source for the punch 1 is provided.
Since the ejector plate 2 is installed at a distance from the center axis 23 of the punch 1, even a slight error during installation or operation will cause the ejector plate 2 to
A force was generated to tilt the punch 1 which was fixed to the center hole, reducing the accuracy of punching the center hole. Furthermore, since the cylinder 4 protrudes toward the platen on the clamping side of the molding machine, the molding machine needs to be modified, which poses problems in terms of molded product quality control and molding equipment.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks and simplifies the configuration.

Structure of the Invention The optical disc molding die of the present invention includes a punch installed in a movable mold half as a means for punching out the central hole of the optical disc within the mold during a molding cycle, and the punch is fixed. A punch plate that moves back and forth; a hydraulic cylinder that is fixed to the side surface of the movable mold half and is a driving source for punching the center hole; and the hydraulic cylinder applies thrust to the forward motion of the punch plate via a fulcrum. It consists of a lever for conversion and a spool bush that is installed in the stationary mold half concentrically with the punch so as to be able to slide back and forth, and allows the central hole of the optical disk to be formed with high precision in the mold closed state. It can be punched in a mold, the overall structure can be simplified, and it is extremely advantageous in terms of molded product quality control and equipment management.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2 to 8. In the figure, 51 is an optical disk molding cavity part, 52 is a punch located in the center of the cavity, 53 is a punch plate that fixes the punch with a nut 54, and 55 is a plurality of guide pins that guide the back and forth movement of the punch plate. , 56 is a hydraulic cylinder, 57 is a lever that converts the forward force of the hydraulic cylinder 56 into the forward punching force of the punch 52, 61 is a spool bushing that can be retracted in synchronization with the advance of the punch 52, and 59 is a lever 5
58 is a block fixed to the rod portion of the hydraulic cylinder 56 and holds the force pin 63; 60 is a forward limit stopper of the hydraulic cylinder; 67 66 is a sleeve pin that protrudes a molded optical disk replica; 66 is a disk-shaped stamper that has optical disk information pits concentrically on its surface; and 68 is a disk-shaped stamper that is placed on a disk plate 69 by a holder 70; This is a protruding levin that protrudes a resin part 72 that includes a spool 76 from which a disk replica is separated.

A recessed portion 64 is formed around the central axis of the punch 52 at the point of action 65 of the lever 57, so that the lever 57 can be attached to the center of the punch plate 53 without affecting the punch fixing nut 54 and the ejector pin 68. Force can be applied to the bottom part.
A gap 74 is provided between the spool bush 61 and the bottom surface of the location ring 81, and when the punch 52 moves forward via the lever 57 due to the operation of the hydraulic cylinder 56, the resin 72 in the center of the cavity 51 is moved between the punch 52 and the punch 52. The spool bush 61 can be moved backward while being sandwiched between the spool bush 61 and the spool bush 61. Therefore, the center hole punching operation can be set arbitrarily during the mold closed state from the completion of injection to the start of mold opening during the molding cycle, and the center axis of the punch 52 and the center axis of the spool bush 61 can be set as desired. The center hole can be punched without causing any misalignment.

Further, the action point of the lever 57 is very close to the central axis of the punch 52, and does not generate a tilting force during the forward movement of the punch 52.

Furthermore, since the relationship between the distance b between the fulcrum and the point of application of the lever and the distance a between the fulcrum and the point of force can be set as a>b, a small hydraulic cylinder 56 can be used to obtain the force necessary for punching the center hole. It is possible to prevent the mold from protruding from the outside of the mold.

Effects of the Invention As described above, in the present invention, the central hole of the optical disc molded product is punched in the mold by converting the thrust of the hydraulic cylinder fixed to the side of the mold via a lever.
This is done by moving the punch forward by acting on the central part of the punch fixed to the punch plate, and the spool bushing, which is installed coaxially with the punch, retreats as the punch moves forward. Since the center hole is punched in the closed state, there is no tilting of the punch center axis or misalignment between the punch center axis and the spool bush center axis, which simplifies the overall configuration and improves molded products. This is extremely advantageous in terms of quality control and mold equipment management. Furthermore, since the hydraulic cylinder that is the drive source for punching the center hole does not protrude beyond the outside of the mold, there is also the advantage that there is no need to modify the molding machine platen.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional optical disk molding die, FIG. 2 is a sectional view of an optical disk molding die according to an embodiment of the present invention, and FIG. 3 is a sectional view of the same.
Fig. 4 is a local sectional view of the main part, Fig. 5 is a front view of the lever, Fig. 6 is a plan view of the lever, Fig. 7 is a partial sectional view, and Fig. 8 is a partial sectional view. It is. 52...Punch, 53...Punch plate, 5
6...Hydraulic cylinder, 57...Lever, 61...
...Spool bushing, 64...dent part.

Claims (1)

[Claims] 1 A mold for manufacturing a replica of an optical disk such as a video disk, a compact disk, a data file disk, etc., in which a center hole of the optical disk is formed in the movable mold half as a means for punching out the central hole in the mold during the molding cycle. A punch installed in
a punch plate that fixes the punch and moves back and forth; and a punch plate that is installed on the side surface of the movable mold half,
A hydraulic cylinder which is a driving source for punching the center hole, a lever which converts the thrust of the hydraulic cylinder into actuating the punch plate via a fulcrum, and a lever which is installed in the stationary mold half concentrically with the punch and is movable back and forth. An optical disc mold having a sprue bush.