JPS58177327A - Apparatus for molding disklike recording medium - Google Patents

Abstract

PURPOSE:To increase the molding accuracy, by arranging, at the central parts of top and bottom forces, center pins having a stamper fixing function and a function for molding a central hole in a recording medium, and making at least one of the center pins of a material whose heat conductivity is higher than that of the top and bottom forces. CONSTITUTION:The top and bottom forces 1, 2 are formed with passages 13, 13' for steam or cooling water for heating or cooling. The upper force includes an upper stamper case 7, an upper stamper 9, and the upper center pin 11, while the bottom force includes a lower stamper case 8, a lower stamper 10 and the lower center pin 13. A melted material injected from an injection cylinder 3 is molded by clamping the top and bottom forces 1, 2 into a disk shape. As the upper and lower center pins 11, 12 are made of a material having a heat conductivity higher than that of the top and bottom forces 11, 12, the heating or cooling function due to heat conduction of the center pins is enhanced, and therefore the accuracy of the section surrounding the center of the recording medium disk can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a molding device for disc-shaped recording media such as audio records and video discs, and particularly relates to an apparatus for molding disc-shaped recording media such as audio records and video discs, and in particular - a molding device that is inserted into the center of an elbow mold and has a stamper fixing function and a lIJ disc-shaped recording medium. It features a center bin that has a media center hole forming function, and by increasing the heating and cooling function of the center bin during molding, it improves the forming precision of the center hole of disk-shaped recording media, increases the longevity of the stamper 6a, and further shortens the forming time. The aim is to shorten the time.

Conventionally, in molding equipment for disc-shaped recording media using resin materials, temperature control of the molding mold, which is composed of a stamper case, stamper, center bin, etc., is essential for molding high-precision, high-quality disc-shaped recording media. This is the most important condition, and in particular, the temperature gear during heating and cooling that occurs between the stamper case and the center bin inserted in the center of the stamper case causes a major problem in forming disk-shaped recording media, and the main cause of this is the It lies in the heating and cooling function of the mold.

Conventional stamper cases and center bins are made of the same medium-carbon steel material, and methane cases have a number of finishing processes inside, and by flowing steam and cooling water at a constant pressure through the finishings, the case surface is However, the center pin does not have its own heating and cooling function, but is heated and cooled using heat conduction from the stamper case, and has a significantly higher heating and cooling rate than the stamper case. This is because the functionality is inferior. As a result, the following disadvantages occur.

G) In the center hole molding of a disc-shaped recording medium, the cooling characteristics of the center pin, which has the function of forming the center hole, are poor, so the resin material near the center is taken out without being sufficiently cooled during compression molding, and the thermal shrinkage balance cannot be maintained, resulting in a problem after molding. Internal stress distortion occurs, which deteriorates dimensional accuracy and shape accuracy near the center hole.

@ Disc-shaped recording media In the mold that was heated during compression molding, the heating characteristics were poor and the resin material came into contact with the unheated center pin, causing the lh additive contained inside to precipitate, causing the stamper to deteriorate. This will cause dirt and scratches on the stamper and reduce the lifespan of the stamper.

Prolonging the cooling time reduces productivity, etc., and this problem is particularly caused by disk-shaped recording medium molding devices that use the injection compression method, in other words, because the center pin is docked with the injection nozzle and has an injection nozzle function. The diameter of the center pin increases, and it becomes larger when the mass increases.

The present invention solves the above problems and achieves higher accuracy.

In order to form high-quality disk-shaped recording media, the center pin, which was conventionally made of the same material as the stamper case, was made of a material with a thermal conductivity (7)11"h higher than that of the stamper case material. The purpose is to enhance the heating and cooling function of the pin.The present invention is not limited to the center pin of the triQ-) output compression method, but can also be adopted in Ike's Type 11, and the heating and cooling function of the center pin is improved. It is something that enhances.

Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 shows the overall front configuration of an injection molding device.
Book 9 of this device! It shows the positional relationship of each element regarding llI. In FIG.

Reference numeral 1 indicates a lower molding die, and numeral 2 indicates a lower forming die, each of which includes a stamper case, a stamper, and a center pin, and constitutes a die equipped with a pair of heating and cooling units. 3 is an injection cylinder, 4
indicates the injection nozzle, and in Fig. 2, the upper and lower molds 1,
The configuration and operational functions of 2 will be explained in detail, and an embodiment of the present invention will be shown.

In Fig. 2, 1 is the lower molding die and the upper stamper case 7
, an upper stamper 9 and an upper center bin 11,
The lower mold is composed of a lower stamper case 8, a lower stamper 10, and a lower center bin 12. - The upper and lower stamper cases 7 and 8 are made of medium carbon steel material with excellent toughness, and each has a finishing process of 13°13' to selectively allow steam and cooling water to flow inside, and is equipped with a heating and cooling function. There is. The stampers 9 and 10 each have a pair of upper and lower center bins 11.
12 is press-fitted into the center of the upper and lower stamper cases 7.8 and fixed at the tapered parts 14 and 14', and by inserting the fixing arrows 15 and 15', the upper and lower stamper cases 7.8 are firmly fixed. The center is fixed to the opposite surface of the Reference numeral 3 denotes an injection cylinder which supplies resin material 6 through a scree 5 provided inside, and the heated plasticized resin material 6 is discharged upward from the outlet of the nozzle 4 which is combined with the center hole of the upper center bin 11 by the injection operation of the scree 6. Center bin 1
1 is injected between the upper and lower molding molds 1 and 2 which are clamped together through the molds 1 and 2, and compression molded to a predetermined size and shape. The center hole of the disc-shaped recording medium is formed by the fitting action of the disc-shaped recording medium. In the present invention, the pair of upper and lower center bins 11.12 constituting the upper and lower molding dies 1, 2 are made of a material having higher thermal conductivity than the material of the stamper case 7.8, for example, phosphor bronze, aluminum alloy, etc. By constructing the upper and lower center bins 11 and 12 from copper or the like, the heating and cooling function of the upper and lower center bins 11 and 12 by heat conduction is enhanced, thereby providing a molding die that provides optimal molding conditions for disc-shaped recording media. Furthermore, in the embodiment, the surfaces of the upper and lower center bins 11, 12 are coated with a high hard metal coating 17, 17' such as titanium or chromium in order to improve the toughness and abrasion resistance and increase the practical value. Note that FIGS. 1 and 2 are embodiments of an injection compression type molding apparatus, and the present invention can also be applied to center bins of other types.

FIG. 3 shows an embodiment of a pair of upper and lower center bins 11 and 12 of the present invention, which employs a method of compression molding a preformed resin material 6 in a fixed amount using a pair of upper and lower molding molds 1.2. .

FIG. 4 is a diagram showing still another example of application of the present invention, in which the pair of upper and lower center pins 11° and 120 are made of different materials, for example, the upper center pin 11 is made of conventional medium carbon steel. By constructing the lower center pin 12 with phosphor bronze, etc., which has high thermal conductivity, the heating and cooling function of the lower center pin 12 is enhanced, and the difference in the coefficient of thermal expansion of each material is utilized. The uneven portion 1 of the pair of L lower center pins 11 and 12 during hot forming
It is also possible to improve the fitting precision of No. 6 and to achieve the dimensional precision of forming the center hole of the disk-shaped recording medium and the effect of preventing pars.

As described above, the present invention improves the heating and cooling function of the center bin by configuring the center bin in the molding die with a material having higher thermal conductivity than the material of the stamper case 7.8, and prevents molding during cooling. This eliminates stress distortion in the resin material due to heat shrinkage balance near the center hole where the disc-shaped recording medium contacts the center bin, and improves the hole diameter accuracy and surface accuracy of the center hole.

In addition, by increasing the heating function of the center bin when heating the mold, it maintains the fluidity of the resin material, prevents the additives contained inside from precipitation due to temperature changes, prevents staining and damage to the stamper, and extends the life of the stamper. Stretch out.

Furthermore, the heating and cooling function of the center bin is enhanced, reducing heating and cooling time and increasing productivity.

In general, metal materials with high thermal conductivity often have a high coefficient of thermal expansion, and in this case, the accuracy of fitting between the stamper case, center, and bottle increases during hot forming, thereby improving the fixing function of the stamper. Furthermore, as shown in the application example in Figure 4, when the J4F+ and +114 compositions are changed for a pair of upper and lower center pins, the fitting accuracy of the uneven parts of the upper and lower center pins can be improved, and the hole diameter accuracy of the center hole and the effect of preventing burrs can be improved. Demonstrate.

Furthermore, as in the embodiment, by coating the surface of the center bin with a highly hard metal, the practical value of the center bin made of a highly thermally conductive material can be greatly increased. It has the following effects.

[Brief explanation of drawings]

FIG. 1 is a front view schematically showing the overall configuration of an injection type disc-shaped recording medium molding apparatus according to an embodiment of the present invention, FIG. 2 is a sectional view of the same essential parts, and FIG. FIG. 4 is a cross-sectional view of a main part of a further embodiment of the present invention. 1... Soil mold, 2... Lower mold, 3... Injection sill, 4... Nozzle, 6...・Screw. 6... Resin material, 7... Upper stamper case, 8... Lower stamper case, 9...
・Upper stamper, 1o...■ Stamper, 11...
...Upper center pin, 12...Lower center pin, 13.13'...Hole A, 14°14'
...Taber processing part, 16.15'...Fixed arrow, 16...Irregular part, 1 end, 17'...
・Highly hard metal coating. 15 Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] [1] A center bin having a function of fixing a stamper and a function of forming a center hole of a disc-shaped recording medium is provided in the center of an upper and lower mold having heating and cooling functions, and at least one of the center bins is A molding device for a disk-shaped recording medium, characterized in that the molding device is made of a material having higher thermal conductivity than the material forming the mold. [21 Feature rT+ characterized in that the surface of the center bin is coated with a highly hard metal such as titanium or chromium: Disc-shaped recording medium forming apparatus l'i"0 [3] The tip of the pair of center bins is formed with four parts and a convex part that engage with the horsefly, and the materials forming the two center bins are made to have different coefficients of thermal expansion kt14. A device for forming a disk-shaped recording medium according to item 1 of the patent application.