JPS6391216A - Molding mold - Google Patents

Abstract

PURPOSE:To prevent dispersion in dimensions of a cavity due to distortion of a heat insulation plate by making a degree of parallel processing of the outer most layer into high accuracy, by a method wherein both the said outer most layers of the heat insulation plate to be fitted between a molding part and supporting mold in a molding mold are made of a metal. CONSTITUTION:The outer most layers 12b, 12b made of stainless steel are stuck to both sides of a heat insulation layer 12a in a body. After unification, the outer most layers 12a, 12a are made into a heat insulation plate 12 by polishing the surfaces of them and finishing parallelism between both the surfaces into extremely high accuracy. As the heat insulation plate 12 whose accuracy in parallelism is extremely high is interposed between a molding part 13 and supporting mold 11, it is eliminated that a molding surface 13b of the molding part 13 is bent. As a heat insulation plate 32 is manufactured also in the same manner as a foregoing method, there is no distortion on a molding surface 40a of a molding part 33. Therefore, a form of a cavity 50 to be formed of the molding surfaces 13b, 40a turns accurate.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a molding die used for manufacturing precision molded products such as substrates for optical disks.

(Prior Art) Generally, extremely high surface finishing precision is required for substrates for optical disks and magnetic disks. When manufacturing these substrates by injection molding, it is known that thermal management of the molten resin and the cutting portion of the mold has a large effect on the surface finish accuracy.

Thermal management of the molding section mentioned above is extremely important, along with the thermal management of the molten resin, from the viewpoints of uniform filling of the molten resin into the cavity, closeness between the molding surface of the molding section and the molten resin, solidification history of the molten resin, etc. It is.

Therefore, in addition to quickly responding to the heat medium for heating or cooling to achieve precise temperature control, the heating-cooling cycle is performed in a short time to improve the surface condition of the molded product and improve productivity. In order to improve this, the volume of the molded part is made as small as possible to reduce the heat capacity of the molded part, and a non-woven material such as plastic is placed between the molded part and the support mold that supports this molded part. Improvements have been made to molding molds, such as inserting a metal heat insulating plate to prevent heat dissipation.

(Problems to be Solved by the Invention) However, although the above-mentioned plastic heat insulating board has an excellent effect on its original purpose of heat insulation, it has a decisive drawback in that it causes a decrease in the finishing accuracy of the molded product. It had

That is, since the heat insulating board is made of plastic, it is difficult to finish the parallelism of both sides of the insulating board with high accuracy and to make the thickness uniform. If such a heat insulating plate with poor machining accuracy is sandwiched between the support mold and the molding part, the molding surface of the molding part will be tilted and distorted, resulting in a cavity with a desired shape, such as a substrate for an optical disk, having a uniform thickness. This prevents the formation of small cavities. Therefore, the thickness of the molded product becomes uneven, distortion occurs on the surface, and finishing accuracy decreases. Moreover, the cavity formed by such a molding surface has a considerable influence on the flow of the molten resin, and is also a factor in inducing internal defects in the molded product.

(Means for Solving the Problems) This invention has been made to solve the above problems, and its gist is to provide heat insulation between the molded part that forms the cavity and the support mold that supports this molded part. In the molding die to which the plate is attached, the heat insulating plate has a sandwich structure of two outermost metal layers and a nonmetallic heat insulating layer sandwiched between the outermost layers. be.

(For Insulation) Both outermost layers of the heat insulating board are made of metal and have good workability, and both sides of the heat insulating board are formed parallel to each other with high precision.

Therefore, even if a heat insulating plate is installed between the molding section and the support mold, the molding surface of the molding section will not be tilted or otherwise distorted, and a cavity of the desired shape will be accurately formed.

In addition, by placing a heat insulating plate with a heat insulating layer on the back of the molding section, the heat of the molding section is not transferred to the support mold, etc., and the volume of the molding section, which is repeatedly heated and cooled, is reduced. By doing so, the heat capacity can be reduced. Therefore, the molding section can be accurately and quickly thermally managed. .

(Example) Hereinafter, an example of the present invention will be described based on the drawing of FIG.

Reference numeral 1 in the figure is an injection mold, which in this embodiment is used to mold an optical disk substrate.

The injection mold 1 has a fixed mold 10 and a movable mold 30.

The fixed mold 10 has a metal support mold 11.
A heat insulating plate 12 and a molding part 13 are fixed to the movable mold 30 side of the mold 1.

Specifically, the heat insulating board 12 has a disk shape and has a three-layer sandwich structure. The middle layer is the insulation layer 12
a, the heat insulating layer 12a is made of plastic (non-metallic) made of polyether sulfon or the like. This heat insulating layer 12a is sandwiched between stainless steel (metallic) outermost layers 12b disposed on both sides. The heat insulating board 12 is formed as follows. Immediately, the plastic heat insulating layer 12a
After bonding and integrating the metal outermost layer 121) on both the left and right sides, the surface of the outermost layer is polished to finish the parallelism of both surfaces to extremely high precision.

Further, the molded portion 13 has a disk shape and is made of a metal with extremely high thermal conductivity. Movable mold 3 of this molding part 13
A stepped portion 13a is formed at the outer peripheral end on the 0 side, and the molded portion 1
The movable mold 30 side surface of No. 3 is a molding surface 13b having highly precise smoothness.

The heat insulating plate 12 is fixed to the four-shaped portion 13 by bolts 14, and a flow path 15 for a heat medium is formed in a spiral shape between the heat insulating plate 12 and the molded portion 13. Further, the heat insulating plate 12 and the molded part 13 are fixed to the support mold 11 with bolts 16.

Note that the flow path 15 is connected to a heat medium supply device (none of which is shown) equipped with a temperature control device.

A ring 17 is arranged around the outer periphery of the heat insulating plate 12 and the molded part 13. The ring 17 has a stepped portion 17a formed at its inner peripheral end on the side of the movable mold 30, and is fixed to the support mold 11 with bolts (not shown).

Further, a spool bushing receiving member 18 is fixed through the center of the heat insulating plate 12 and the molding part 13, and furthermore, a spool bushing receiving member 18 is fixed to the center of the spool bushing receiving member 18 and the support mold 11.
A spool bushing 19 having a diameter 9a is fixed therethrough.

On the other hand, the movable mold 30 has a metal support mold 31, and a recess 31a is formed in the center of the support mold 31 on the fixed mold 10 side. A heat insulating plate 32 and a molded part 33 are inserted and fixed into the four parts 31a. The structure of the heat insulating plate 32 and the forming part 33 is basically the same as that of the above fixed mold 10.
Since this is similar to the above, the description of the same aspects will be limited to a general description.

The heat insulating board 32 has a three-layer sandwich structure consisting of a heat insulating layer 32a made of plastic and an outermost layer 32b made of stainless steel, and is shaped like a disk.

Further, the molded portion 33 has a disk shape and is made of metal with extremely good heat transfer coefficient. Fixed mold 1 of this molding part 33
A stepped portion 33a is formed at the outer peripheral end portion on the 0 side.

Then, the heat insulating plate 32 is attached to the molded portion 33 by bolts 34.
A flow path 35 for a heat medium is formed in a spiral shape between the heat insulating plate 32 and the molded part 33. Furthermore, the heat insulating plate 32 and the molded part 33 are attached to the support mold 31 by bolts 36.
Fixed.

Note that the flow path 35 is connected to a heat medium supply device (none of which is shown) equipped with a temperature control device.

A record-shaped stamper 40 is arranged on the fixed mold 1 (1 side) of the molding section 33. The stamper 40 has a molding surface 40a in which fine spiral grooves are formed, and the center part of the stamper 40 is It is fixed by a heat insulating plate 32, a molding part 33, and a center core 38 which is inserted and fixed into the support mold 31, and the peripheral edge of the stamper 40 is fixed by a stopper ring 42 which is fixed to a stepped part 33a of the molding part 33 by a bolt 41. ing.

Further, a projecting pin 39 is supported through the center of the center core 38 .

As shown in the figure, when the fixed mold 10 and the movable mold 30 are in a closed state, the injection mold 1 has four parts formed by the stepped part 17a of the ring 17 of the fixed mold 10 and the stepped part 13a of the molding part 13. Fixed mold 1 of support mold 31 in movable mold 30
0 side protrusion 31b and head 42a of stopper ring 42
is inserted, and the molding surface 13b of the molding part 13 and the stamper 40
A cavity 50 is formed at the opening with the molded portion 40a.

In the above configuration, the heat insulating plates 12.32 are the outermost layer 1 on both sides.
2b and 32b are made of stainless steel.

Therefore, after integrating each outermost layer 12b or 32b with a plastic heat insulating plate 12a or 32a sandwiched therebetween, the surface of each outermost layer 12b, 32b must be mechanically polished with high precision. is made, each insulation board 12.32
The parallelism of both sides of the can be achieved with extremely high precision.

As a result, in the fixed mold 10, the molded part 13 is connected to the heat insulating plate 12.
When the heat insulating plate 12 is fixed to the support mold 11 with
The disadvantages that conventionally occurred due to the interposition of
The disadvantage that the molding surface 13b of the molding part 13 is tilted and distorted is eliminated. The same applies to the movable mold 30, and the molding part 33 is correctly fixed to the support mold 31 with the heat insulating plate 32 interposed, and the stamper 40 fixed to the molding part 33
The molding surface 40a will not be distorted due to inclination or the like. Furthermore, the adhesion between the mating parts of each member is improved, and leakage of the heat medium and molten resin is prevented.

In this way, a cavity 50 having a desired shape is correctly formed between the molding surface 13b of the molding part 13 of the fixed mold 10 and the molding surface 40a of the stamper 40 of the movable mold 30, which are set correctly. This improves the fluidity of the molten resin when it is injected into the cavity 50.

Further, during injection molding, a heating medium and a cooling medium flow through the flow path 15 of the fixed mold 10 and the flow path 35 of the movable mold 30, and each molding part 13, 33 and stamper 40 have a predetermined history. Heat managed.

At this time, the heat insulating layers 12a and 32a of each heat insulating plate 12.32 prevent the heat of the heat medium and the heat of the molded part 13.33 from being transferred to the support mold 11.31 side.

Furthermore, since the heat insulating plate 12.32 is interposed between the support mold 11.31 and the molding part 13.33, the heat capacity of the parts to be thermally managed, that is, the molding part 13.33 and the stamper 40, can be reduced. It's possible to do that.

As a result, by quickly and accurately controlling the temperature of the molding section 13.33 and the stamper 40, extremely precise thermal management is achieved.

Therefore, according to this injection molding apparatus 1, it is possible to mold an optical disk substrate with high finish accuracy and no defects in appearance or internal structure.

This invention is not limited to the above-mentioned embodiments, and various embodiments are possible. For example, the heat insulating layer of the heat insulating board may be formed of a plastic other than polyether sulfon, or may be formed of a Q non-metal such as ceramic as long as it has heat insulating properties.

In addition, the heat insulating board is not limited to three layers, for example, the heat insulating board may be made of a multilayer of plastic and ceramic as described in - to form a heat insulating) vI,
These may be sandwiched between outermost metal layers to form a multilayer sandwich structure.

Furthermore, the molding die is not limited to one for molding optical disk substrates, and may be for molding magnetic disk substrates. In the case of molding a magnetic disk substrate, the stamper in the above embodiment is not required.

(Effects of the Invention) As explained above, according to the present invention, since both outermost layers of the heat insulating board are made of metal, the heat insulating board can be removed by processing both side surfaces of the heat insulating board parallel to each other with high precision.

As a result, the molding part is correctly attached to the support mold with the heat insulating plate interposed therebetween, and the molding part can accurately form a cavity of the desired shape.

Further, by disposing a heat insulating plate having a heat insulating layer on the back of the molding part, the heat of the molding part is not transferred to the support mold or the like. Furthermore, the volume of the molded part can be reduced to reduce the heat capacity. As a result, the molded part is thermally managed accurately and quickly.

Therefore, the finishing accuracy of molded products is improved, and
Productivity improves.

[Brief explanation of the drawing]

The drawing in FIG. 1 shows one embodiment of the present invention,
FIG. 3 is a sectional view of a main part of a molding die. 1... Molding die, 11.31... Support mold, 12
．． 32... Heat insulation board, 12a, 32a... Heat insulation layer, 12b, 32b... Outermost layer, 13.33...
Molding part, 50...cavity.

Claims (1)

[Claims] (1) In a molding die in which a heat insulating plate is installed between a molding part that forms a cavity and a supporting mold that supports this molding part, the heat insulating board is sandwiched between both outermost metal layers and this outermost layer. A molding die characterized by having a sandwich structure with a non-metallic heat insulating layer.