JP2006192651A - Mold - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mold having a temperature conditioning circuit which realizes a high quality molding method for suppressing the warpage of an optical disk substrate. <P>SOLUTION: Multistage fixed mirror surface core temperature conditioning circuits 32-1 to 32-3 and movable mirror surface core temperature conditioning circuits 33-1 to 33-3 are respectively provided to a fixed mirror surface core 25 and a movable mirror surface core 29, and the distances from the temperature conditioning circuits 32-1 to 32-3 to a cavity 23 are optimized in inner, middle and outer peripheries to equalize the surface temperature distribution of the optical disk after molding and ejection when a fluid is passed through the temperature conditioning grooves which constitute the temperature conditioning circuits 32-1 to 32-3 and 33-1 to 33-3. Accordingly, the optical disk substrate of high quality having no warpage can be produced. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a molding die for the purpose of high-quality molding of a plate-like molded product, and more particularly to an optical disc molding die.

  As a temperature control circuit structure of a conventional optical disk molding die, there is one in which the distance between the cavity (product part) and the top of the temperature control circuit inner wall cavity side of each of the fixed side and movable side mirror inserts is uniform (for example, Patent Document 1).

  FIG. 3 shows a temperature control circuit structure of a conventional optical disk molding die described in Patent Document 1. In FIG. As shown in FIG. 3, the mold apparatus includes a fixed mold part 20 and a movable mold part 21 that is moved toward and away from the fixed mold part 20. A closed space formed by the mold part 20, the movable mold part 21, and the outer peripheral ring 22 attached to the fixed mold part 20 is a cavity 23 filled with a molding material from the injection device. In the mold apparatus 13, the outer periphery of the disk substrate to be molded is defined by closing the outer peripheral portion of the cavity 23 by the outer peripheral ring 22.

  The fixed-side mold part 20 includes a fixed-side mounting plate 24, a fixed-side mirror surface insert 25 provided on the fixed-side mount plate 24, and one surface of the fixed-side mirror surface insert 25, specifically, a surface on the cavity 23 side. And a stamper 26 attached to the head. A sprue bush 27 having a sprue 27 a for supplying a molding material into the cavity 23 is disposed at the center of the solid side mounting plate 24.

  The stamper 26 serves as a master for forming a disk substrate, and an uneven pattern for transferring to the disk substrate is formed on one surface, specifically, the surface disposed on the cavity 23 side. The stamper 26 is mounted on the fixed mirror end insert 25 by holding the vicinity of the outermost periphery by a part of the outer peripheral ring 22 described above. Further, the position of the innermost circumferential side of the stamper 26 is regulated by an inner diameter guide (not shown).

  The movable-side mold part 21 includes a movable-side mounting plate 28 and a movable-side mirror insert 29 provided on the movable-side mounting plate 28, and a center pin 30 and a gate cut punch 31 are arranged at the center. It is installed.

In such a mold apparatus, the mold temperature at the time of molding the disk substrate is adjusted by the temperature control circuits 32 and 33 provided in the fixed side mirror surface insert 25 and the movable side mirror insert 29, respectively. The temperature control circuits 32 and 33 are constituted by grooves through which a fluid passes.
JP 2003-305756 A

  In the conventional configuration shown in FIG. 3, the temperature control circuit 32 of the fixed mirror surface insert 25 and the temperature control circuit 33 of the movable mirror insert 29 have a uniform distance to the cavity 23.

  However, in the conventional configuration, the temperature control circuit is evenly arranged on the inner peripheral part of the cavity having a large heat capacity due to the influence of the sprue part having a large resin volume with respect to the surface area in contact with the mold rather than the outer peripheral part of the cavity. In the product after taking out, the temperature distribution is varied, and the product warpage occurs due to the deviation of the shrinkage timing, and there is a problem that a product of stable quality cannot be produced.

  The present invention solves the above-mentioned conventional problems, and an object thereof is to provide a molding die having a temperature control circuit structure for obtaining a high-quality product.

In order to achieve the above-mentioned object, it is constituted by a fixed side mirror surface nest, a movable side mirror surface nest, and a temperature control groove for passing a fluid provided in at least one of the fixed side mirror surface nest or the movable side mirror surface nest, In a molding die for forming a cavity having two parallel planes on a wall surface by combining a fixed side mirror surface insert and the movable side mirror insert, and passing through the center of a sprue portion for supplying a molding material to the cavity, the cavity plane In a vertical cross section, the distance between the top of the cavity side of the nth temperature control groove cross section from the center of the sprue section and the plane of the inner wall of the cavity is L _n, and n + 1 th from the center of the sprue section. when the said cavity-side of the top of the temperature regulating groove section, the distance between the plane of the inner wall of the cavity was _{L n + 1, L n <} L n + And satisfies the relation.

  According to the present invention, the molding die is for optical disc molding.

  With such a configuration, it is possible to stabilize the surface temperatures at the inner circumference, middle circumference, and outer circumference of the optical disc substrate after molding, and to reduce the amount of product warpage.

  According to the present invention, it is possible to reduce warpage of a product after molding. Further, by realizing appropriate temperature control, higher cycle molding becomes possible, and transferability of products that require higher density molding such as DVD-R and DVD-RAM can be improved.

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

  FIG. 1 is a cross-sectional view showing an outline of a temperature control circuit structure of an optical disk molding die according to an embodiment of the present invention. In FIG. 1, the same members or members having the same functions as those in the prior art shown in FIG.

  In FIG. 1, a fixed-side mirror nesting temperature adjustment circuit 32-1 in the fixed-side mirror nesting 25 is a temperature adjustment circuit in the inner periphery of the cavity 23, and a fixed-side mirror nesting temperature adjustment circuit 32-2 is located in the cavity 23. The fixed-side specular nesting temperature control circuit 32-3 is a temperature control circuit at the outer periphery of the cavity 23. That is, the temperature adjustment circuit 32 is configured so that the fluid circulates around the inner circumference, the middle circumference, and the outer circumference of the fixed-side mirror insert 25. Similarly, for the movable side mirror nesting 29, the inner peripheral part is a movable side mirror nesting temperature adjustment circuit 33-1, the middle part is a movable side mirror nesting temperature adjustment circuit 33-2, and the outer part is a movable side mirror nesting temperature adjustment circuit. As in the circuit 33-3, the temperature-control circuit 33 is configured so that the movable mirror surface insert 33 has a fluid circulating around the inner circumference, the middle circumference, and the outer circumference. Further, the distances from the top on the inner wall cavity 23 side to the plane of the cavity 23 in the fixed side mirror surface nesting temperature adjusting circuits 32-1 to 3 and the movable side mirror surface nesting temperature adjusting circuits 33-1 to 33-3 are determined as the inner circumference, the middle circumference, and the outer circumference. It is changed in multiple stages so as to increase in this order.

  In the above-described embodiment, the temperature control circuits 32 and 33 are formed of three grooves in a cross section that passes through the center of the sprue 27a that supplies the molding material to the cavity 23 and is perpendicular to the plane of the cavity 23. The temperature control circuits 32 and 33 may be configured by a larger number of grooves. In this case, the following conditions must be satisfied.

In the cross section passing through the center of the sprue 27a that supplies the molding material to the cavity 23 and perpendicular to the plane of the cavity 23, the top of the groove constituting the temperature control circuit 32, 33 on the cavity 23 side and the plane of the inner wall of the cavity 23 , L is the distance between the inner wall close to the sprue 27a and the center of the sprue 27a in the grooves constituting the temperature control circuits 32 and 33, and the grooves are n-grooves in order from the closest to the sprue 27a. (Where n is a natural number), the distance R in the cross-sectional n-groove is R _n , the distance L is L _n , the groove adjacent to the side far from the sprue 27a with respect to the cross-sectional n-groove is the cross-sectional n + 1 groove, and the cross-section n + 1 groove distance R Is R _{n + 1} and the distance L is L _{n + 1} ,
If R _n <R _{n + 1,} then L _n <L _{n + 1}
The size of each groove constituting the temperature control circuits 32 and 33 is set so as to satisfy the relationship.

  In this way, the temperature control circuit is configured in multiple stages from the inner periphery with a large heat capacity, and by taking an optimal layout, molding under low temperature conditions with less shrinkage variation and less warping is possible. The surface temperature distribution of the optical disk substrate is stabilized. Thereby, it is possible to produce a high-quality optical disc with suppressed substrate warpage.

  FIG. 2 is a graph summarizing the results of molding the DVD-RAM in this embodiment. In this embodiment, the temperature control circuit is arranged in a spiral shape using water as a medium, and the distance from the top on the temperature control circuit inner wall cavity side to the cavity is set by several analyzes and simulations.

  In the conventional method, the temperature of the inner periphery of the data recording surface of the product immediately after removal is as high as about 130 ° C., and the temperature difference from the outer periphery of the data recording surface is about 6 ° C., so that the product warpage is unstable. On the other hand, according to the present embodiment, the temperature difference between the inner and outer circumferences of the data recording surface is 2 ° C., and the product surface temperature can be lowered immediately after taking out by about 10 ° C. from the conventional method. Thus, it can be seen that the molding temperature can be lowered by about 10 ° C. on the data recording surface, and the variation of the surface temperature of the molded product immediately after the removal is also suppressed to about １ ／. As a result, the amount of product warpage can be reduced.

  In the present embodiment, the DVD-RAM substrate molding is taken as an example, but the present invention may be applied to other optical disk substrates and precision thin-wall molding methods including DVD-R.

  INDUSTRIAL APPLICABILITY The present invention can be applied to a molding die that uses a fluid as a temperature control circuit medium in an optical disc molding die or a molding die that produces a precision thin-walled product.

Sectional drawing which shows schematic structure of the temperature control circuit of the optical disk molding die in one embodiment of this invention The graph which shows the result of having shape | molded DVD-RAM in this Embodiment Schematic diagram of conventional optical disk molding die temperature control circuit structure

Explanation of symbols

23 Cavity (Product part)
25 Fixed side mirror surface nesting 29 Movable side mirror surface nesting 32, 32-1, 32-2, 32-3 Fixed side mirror surface nesting temperature control circuit 33, 33-1, 33-2, 33-3 Fixed side mirror surface nesting temperature control circuit

Claims (2)

The fixed-side mirror surface nesting, the movable-side mirror surface nesting, and a temperature control groove for passing a fluid provided in at least one of the fixed-side mirror surface nesting or the movable-side mirror surface nesting, and the fixed-side mirror surface nesting and the movable side In a mold that combines a mirror insert and forms a cavity with two parallel planes on the wall,
In a cross section that passes through the center of the sprue portion that supplies the molding material to the cavity and is perpendicular to the cavity plane,
The distance between the top of the nth temperature control groove section from the center of the sprue part on the cavity side and the plane of the inner wall of the cavity is L _n ,
When the distance between the top of the n + 1 th temperature control groove cross section from the center of the sprue portion on the cavity side and the plane of the inner wall of the cavity is L _{n + 1} ,
A molding die characterized by satisfying a relationship of L _n <L _{n + 1} .   2. The molding die according to claim 1, wherein the molding die is for optical disc molding.

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