JP2005306011A - Molding method of recording disc, molding apparatus for recording disc and mold for recording disc - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold having a simple structure and suppressing a generation of eccentricity on a substrate in a case of molding a substrate with a center hole with a mold. <P>SOLUTION: In a stamping molding, a molten resin is injected through a sprue bush 2 into a cavity 14 in a state as a movable mold 11 to be opened by 0.4 mm from a fixed mold 1. Next, by carrying out a clamping (pressure:10 t to 35 t), under moving the movable mold 11, the mold closing is carried out, by forming a center hole 6a of a molded substrate 6 at the outer periphery of a cut punch 12 fixed and protruded to the movable mold 11, the resin in the sprue bush 2 and the resin in the cavity 14 is cut off. Then the movable mold 11 is opened, and the molded substrate 6 is taken out. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a recording disk forming method and apparatus for forming a disc-shaped recording disk substrate having a central hole, and a forming die used in the method and apparatus.

  A substrate of an optical disk such as a CD or DVD is generally injection-molded with a resin.

  As a mold apparatus used for this injection molding, for example, one described in Patent Document 1 is known. In this mold apparatus, a pair of molds, a fixed mold (fixed side assembly) and a movable mold (movable side assembly) are closed, and a product cavity (cavity space) is formed between the fixed mold and the movable mold. The product cavity is filled with a molten resin as a molding material, and after the resin in the product cavity, that is, the optical disk is solidified, the fixed mold and the movable mold are opened, and the molded optical disk is taken out. ing.

  Resin is injected into the product cavity from a sprue disposed at a position corresponding to the center of the product cavity. Further, the center portion of the optical disk is formed by sliding a cut punch, which is a gate cut member provided on the movable mold side, into the fixed mold side and entering a recess (die) of the sprue bush provided on the fixed mold side. Are formed, and the resin in the sprue and the resin in the product cavity are cut.

Further, a configuration in which a positioning ring (guide ring) fixed to each of a fixed mold and a movable mold is provided, or a structure in which a post (guide post) as described in Patent Document 2 is provided is proposed.
JP-A-11-70529 JP 2002-254480 A

  As described above, as a mold apparatus structure used in conventional injection molding, generally, a gate cut member is slid to form an opening hole in the center of an optical disc, and a resin in a sprue and a resin in a product cavity. In this case, it is necessary to make a mold structure corresponding to the sliding of the gate cut member, the mold cost is high, and the gate cut member The occurrence of eccentricity of the molded substrate due to sliding and wear becomes a problem.

  An object of the present invention is to solve the problems of the prior art, and when molding a substrate having a center hole, a recording disk molding that has a simple mold structure and can suppress the occurrence of eccentricity of the substrate. It is an object to provide a method, a recording disk forming apparatus, and a recording disk forming mold.

  In order to achieve the above object, a recording disk forming method according to the present invention is a recording disk forming method for forming a disk-shaped recording disk substrate having a center hole. A recording disk forming method comprising a pair of dies that are formed between a ring-shaped gate that opens at a position corresponding to a side surface of a central hole and that opens and closes when the dies are closed, wherein a gate cutter member is slid The center hole is formed by clamping in a fixed state.

  The recording disk forming apparatus according to the present invention is a recording disk forming apparatus for forming a disk-shaped recording disk substrate having a center hole, and a cavity having the shape of the substrate, and a cavity on the side surface of the center hole. A recording disk forming apparatus having a pair of molds that are formed between the ring-shaped gates that open at corresponding positions to open and close when the mold is closed, and the gate cutter member is fixed without sliding. It is characterized by.

  Further, the recording disk forming die according to the present invention is characterized in that a gate cutter member that forms a center hole at the time of clamping is fixed.

  According to the present invention, since the gate cutter member is fixed without moving with respect to the mold, there is no mold part that slides (wears), so that the mold structure can reduce the cost accordingly. Become. Further, since there is no sliding (abrasion) in the mold, the eccentricity of the molded substrate can be reduced accordingly. In addition, since the gate can be freely adjusted by the mold opening amount, when the substrate of the optical recording disk is formed, the optical characteristics (birefringence, etc.) can be freely adjusted.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In the present embodiment, a stamping molding method is used as the substrate manufacturing method, and the molding apparatus (injection molding machine) can be any molding apparatus that can execute the stamping molding method (a method of molding by opening a mold). can do.

  The stamping molding method is a method in which a molten resin is injected into a mold cavity with the mold slightly opened, and then the mold is clamped to obtain a molded product having the same shape as the mold cavity. In this stamping molding method, it is possible to cut the resin in the sprue and the resin in the product cavity by forming an opening hole in the center part of the disk substrate that is molded by the convex part of the center hole at the same time as clamping the mold. It is.

  1A to 1C are partial cross-sectional views for explaining the configuration and mold operation of Embodiment 1 of the present invention.

  In FIG. 1A, the mold is a mold for DVD 0.6 mm, and is composed of two plates of a fixed mold (fixed side assembly) 1 and a movable mold (movable side assembly) 11.

  The fixed mold 1 is provided with a sprue bush 2 for injecting a molten resin of molding resin (sprue resin), a fixed mirror core 4 for fixing the stamper 3, and an inner stamper holder 5.

  On the other hand, the movable die 11 has a cavity formed by a convex portion (protrusion amount 0.7 mm) of a cut punch 12 as a gate cutter member that forms a center hole as will be described later in the central portion of the molded substrate, and a movable mirror core 13. A cavity 15 forming 14 is fixed.

  FIG. 2 is a cross-sectional view for explaining a configuration related to a cut punch. In the first embodiment, a cut punch 12 having a convex shape as a whole is inserted into and fixed to a movable mirror core 13 by press fitting or the like. Yes. By doing so, the accuracy of position control is improved, and when the gate cutter is performed, the eccentricity accuracy of the molded substrate can be improved, and maintenance, replacement, and repair of the cut punch 12 are facilitated. Become.

  Then, by a stamping molding method, with the movable mold 11 opened 0.4 mm from the fixed mold 1, as shown in FIG. 1B, molten resin is injected from the sprue bush 2 and the resin is poured into the cavity 14. . Next, by performing mold clamping (pressure: 10t to 35t), the movable mold 11 is moved to close the mold, and the center hole 6a of the molded substrate 6 is formed on the outer periphery of the cut punch 12, and the sprue bushing is formed. The resin in 2 and the resin in the cavity 14 are cut.

  Then, as shown in FIG.1 (c), the movable mold | type 11 is opened and the shaping | molding board | substrate 6 is taken out.

  FIG. 3 is a partial cross-sectional view for explaining the configuration of the second embodiment of the present invention, and FIG. 4 is a front view of the movable mirror core in the second embodiment.

  In the first embodiment, the cut punch 12 is formed of a separate member from the movable mirror core 13 and the cut punch 12 is pressed into the movable mirror core 13 and fixed. However, in the second embodiment, As shown in FIG. 4, the difference is that the cut punch 20a portion is formed integrally with the movable mirror core 20.

  By integrating the movable mirror surface core 20 and the cut punch 20a as in the second embodiment, it is possible to prevent displacement due to clearance between components, misalignment that occurs during assembly, and the like, and therefore the cut punch 20a. The accuracy of the position control is improved, and the eccentric accuracy of the molded substrate can be further improved when the gate is cut.

  5A to 5C are partial cross-sectional views for explaining the configuration and mold operation of the third embodiment of the present invention.

  In FIG. 5A, the mold is a mold for DVD 0.6 mm, as in the first embodiment, and is a fixed mold 1 (fixed side assembly) and a movable mold 11 (movable side assembly). It consists of a plate.

  The fixed mold 1 is provided with a sprue bush 2 for injecting a molten resin of molding resin (sprue resin), a fixed mirror core 4 for fixing the stamper 3, and an inner stamper holder 5.

  On the other hand, the movable die 11 has a cavity 15 that forms a cavity 14 by a convex portion (protrusion amount 0.7 mm) of a cut punch 12 as a gate cutter member that forms a center hole of a molded substrate and a movable mirror core 13. The floating punch 16 having a protruding structure for taking out the product is movably provided.

  Then, by a stamping molding method, with the movable die 11 opened by 0.4 mm from the fixed die 1, as shown in FIG. 5B, molten resin is injected from the sprue bush 2 and the resin is poured into the cavity 14. Next, by performing mold clamping (pressure: 10t to 35t), the movable mold 11 is moved to close the mold, and the center portion 6a of the molded substrate 6 is formed on the outer periphery of the cut punch 12, and the sprue bushing is formed. The resin in 2 and the resin in the cavity 14 are cut.

  Thereafter, as shown in FIG. 5C, the movable die 11 is opened, and the floating punch 16 is moved to take out the molded substrate 6 from the movable die 11.

  FIG. 6 is a partial cross-sectional view for explaining a main part of the fourth embodiment of the present invention.

  In the fourth embodiment, similarly to the floating punch 16 of the third embodiment, a floating punch 21 for taking out a molded product is provided on the outer periphery of the cut punch 12 fixed to the movable mirror surface core 13 so as to be movable up and down. A pin-shaped pushing member 22 is provided on a part of the outer periphery of the punch 12 so as to be able to be pushed in from the bottom surface of the movable mirror core 13 so as to correspond to the leg 21 a provided on the floating punch 21. By doing in this way, the molded product after a gate cutter can be easily taken out from a type | mold, and workability | operativity improves.

  The floating punch 21 is inserted from the surface side (cavity 14 side) of the movable mirror core 13.

  7A to 7C are partial cross-sectional views for explaining the configuration and mold operation of the fifth embodiment of the present invention.

  In FIG. 7A, the mold is a mold for DVD 0.6 mm, as in the above embodiment, and is a fixed mold 1 (fixed side assembly) and a movable mold 11 (movable side assembly). It consists of a plate.

  The fixed mold 1 has a sprue bush 2 for injecting a molten resin of a molding resin (a sprue resin) and a convex portion (protrusion amount: 0.7 mm) of a fixed bush 17 as a gate cutter member for forming a central hole of the molded substrate. A fixed mirror surface core 4 for fixing the stamper 3 and an inner stamper holder 5 are provided.

  On the other hand, the movable die 11 is movably provided with a cavity ring 15 that forms a cavity 14 by a movable mirror surface core 13 and a floating punch 18 having a protruding structure for taking out the molded substrate 6.

  Then, as shown in FIG. 7B, by a stamping molding method, molten resin is injected from the sprue bush 2 in a state where the movable mold is opened 0.4 to 0.8 mm from the fixed mold, and the resin is injected into the cavity 14. Pour. Next, by performing mold clamping (pressure: 10 t to 35 t), the movable mold 11 is moved and the mold is closed, and the center portion 6 a of the molded substrate 6 is formed by the fixed bush 17. The resin and the resin in the cavity 14 are cut.

  Thereafter, as shown in FIG. 7C, the movable die 11 is opened, and the floating punch 18 is moved to take out the molded substrate 6 from the movable die 11.

  In the third embodiment, it is conceivable that the gate cutter member is formed by projecting the lower portion of the sprue bush 2 (projection amount: 0.7 mm) without providing the fixed bush 17.

  The verification experiment was performed using a molding device for optical disks (Sumitomo Heavy Industries, Ltd .: electric servo SD35E) and a mold (Seiko Giken Co., Ltd .: DVD mold).

  The mold of the experimental apparatus is a mold for DVD 0.6 mm, and the fixed mold 1 (fixed side assembly) and the movable mold 11 (movable side assembly) having the configuration of the third embodiment shown in FIGS. ), The protrusion of the cut punch 12 is set to a protrusion amount of 0.7 mm, and the movable resin 11 is opened 0.4 to 0.8 mm from the fixed die 1 by a stamping molding method. By injecting from the sprue bush 2 and pouring resin into the cavity and performing mold clamping (pressure 10t to 35t), the center portion 6a of the molded substrate 6 is formed on the outer periphery of the cut punch 12, and the sprue bush 2 The resin and the resin in the cavity 14 are cut, the movable die 11 is opened, and the floating punch 16 is moved so that the molded substrate 6 is ejected from the movable die 11 so as to be taken out.

  Then, when the mold opening amount (gate amount) between the fixed die 1 and the movable die 11 was changed and the optical characteristics (birefringence) were confirmed, data as shown in FIG. 8 was obtained.

The molding conditions were a resin temperature of 390 ° C., a molding cycle of 9.0 seconds, a mold temperature of 128 ° C., and a maximum clamping force of 35 t / 0.1 seconds. Biref126P manufactured by Schenk was used.
(Comparative example): Cut punch sliding type gate 1.0 mm (die opening amount 0.6 mm + die gate amount 0.4 mm), cut punch protrusion amount 0.1 mm / movement amount 0.6 mm
(Example 1): Cut punch fixed type Gate 0.3 mm (die opening amount), protrusion amount of cut punch convex part 0.7 mm / no movement (Example 2): Cut punch fixed type gate 0.5 mm (die Opening amount), protrusion amount of cut punch convex part 0.7 mm / no movement (Example 3): fixed cut punch type gate 0.8 mm (die opening amount), protrusion amount of cut punch convex part 0.7 mm / movement Without FIG. 8, it can be seen that the molded substrates of Examples 1 to 3 molded by the method and apparatus according to the present embodiment have improved optical characteristics compared to the comparative example.

  In this embodiment, the shape of the protrusion (projection) of the gate cutter member may be any shape, but the protrusion amount (height of the protrusion) needs to be at least 0.1 mm, preferably It is good that it is 0.6 mm or more.

  The present invention is applied to molding of a disk substrate having a center hole such as CD-R / RW, CD-ROM, DVD-ROM, DVD + R / RW, DVD-R / RW, DVD-RAM, Blu-Layer, In particular, it is effective for forming a recording disk that requires a simple mold structure to suppress the occurrence of eccentricity of the molded substrate.

(A)-(c) is a partial cross section figure for demonstrating the structure and type | mold operation | movement of Embodiment 1 of this invention. Sectional drawing for demonstrating the structure regarding the cut punch in Embodiment 1. FIG. Partial sectional drawing for demonstrating the structure of Embodiment 2 of this invention Front view of movable mirror core in embodiment 2 (A)-(c) is a partial cross section figure for demonstrating the structure and type | mold operation | movement of Embodiment 3 of this invention. Partial sectional drawing for demonstrating the principal part of Embodiment 4 of this invention (A)-(c) is a partial cross section figure for demonstrating the structure and type | mold operation | movement of Embodiment 5 of this invention. Comparison chart of optical characteristics between examples of the present invention and comparative examples

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fixed type | mold 2 Sprue bush 3 Stamper 4 Fixed mirror surface core 5 Inner stamper holder 6 Molding board | substrate 6a Center hole 11 Movable type | mold 12 Cut punch 13, 20 Movable mirror surface core 14 Cavity 15 Cavity 16, 16 Floating punch 17 Fixed bush 18 Floating punch 18 20a Cut punch 21a integrally formed with movable mirror surface core Leg 22 Extruding member

Claims (12)

  In a recording disk forming method for forming a disk-shaped recording disk substrate having a central hole, a cavity having the shape of the substrate, and a ring-shaped gate opening to the cavity at a position corresponding to a side surface of the central hole. A method of forming a recording disk having a pair of molds that are formed between each other when the mold is closed, and the center hole is formed by clamping the gate cutter member in a fixed state without sliding. A recording disk molding method characterized by the above.   The recording disk forming method according to claim 1, wherein the protrusion of the gate cutter member is protruded by at least 0.1 mm with respect to the opposing mold.   In a recording disk forming apparatus for forming a disk-shaped recording disk substrate having a center hole, a cavity having the shape of the substrate, and a ring-shaped gate opening to the cavity at a position corresponding to the side surface of the center hole A recording disk forming apparatus comprising a pair of molds which are formed between each other and opened and closed when the mold is closed, wherein the gate cutter member is fixed without sliding.   4. The recording disk forming apparatus according to claim 3, wherein the gate is formed on one mold and the gate cutter member is provided on the other mold.   4. The recording disk forming apparatus according to claim 3, wherein the gate cutter member is provided in a mold in which the gate is formed.   6. The recording disk forming apparatus according to claim 3, wherein the protrusion of the gate cutter member protrudes at least 0.1 mm from the opposing mold.   A recording disk molding die for use in the recording disk molding method according to claim 1 or 2, or the recording disk molding apparatus according to any one of claims 3 to 6, wherein a gate cutter member forms a center hole when the mold is clamped. A recording disk molding die characterized by fixing the disk.   8. The recording disk molding die according to claim 7, wherein a mold part for forming the gate cutter member is formed integrally with the molding die.   8. The recording disk molding die according to claim 7, wherein a mold part forming the gate cutter member is a member different from the molding die.   The recording disk molding die according to any one of claims 7 to 9, wherein a die part for taking out a molded product is provided on an outer periphery of a die part forming the gate cutter member.   11. A recording disk molding die according to claim 10, wherein the mold part for taking out the molded product has a pin shape.   12. The recording disk forming die according to claim 10, wherein the mold part is assembled from inside the cavity.

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