JPH02215513A - Molding device with precise mold - Google Patents

Abstract

PURPOSE:To avoid generation of shear stress, by a method wherein the title device is provided with a stamper, monitors temperatures of a matrix and matter to be molded which are set up heatably and coolably and movable throughout the process of contraction of both of them and the temperature of the matrix is controlled so that respective contracting quantities coincide with each other. CONSTITUTION:A matrix 2 is constituted of a moving main body part 6, a variable-temperature body 8 provided in front of the moving main body part 6 through lamination and a stamper 10 made of nickel. An injection hole 4a is formed into a stationary mold 4, a temperature detecting element 26 is mounted on the bottom in a state of the matrix and a temperature variation of a matter 5 to be molded is detected by the first temperature detecting part 30 of a temperature monitoring mechanism 28 with an electromotive force value through a heat gradient between the temperature detecting elements 26 adjoining to each other. A temperature variation of the stamper 10 is detected by the second temperature detecting part 34 of the temperature monitoring mechanism 28. All of detected information are transmitted to a temperature control mechanism 32, the information from the temperature detectors 30, 34 are collated with that and an electric power source 24 is controlled. Since a direction of an electric current is controlled, reversibility in a Peltier effect such as heating capacity and cooling capacity in the variable-temperature body 8 is obtained and a variation of the temperature is contrived.

Description

Detailed Description of the Invention (Industrial Field of Application) This invention is applicable to the following: This invention relates to a molding device using precision molds.

(Prior Art) Generally, recording media such as compact discs, optical discs, and magneto-optical discs are made of polycarbonate.

It is molded using thermoplastic resin such as acrylic or polystyrene by injection molding or injection compression molding, and the transfer of the bit pattern requires precision on the order of submicrons.

Conventionally, molding equipment using precision molds for molding such products uses a movable mother mold equipped with a nickel stamper having a predetermined molding pattern surface.

Injection molding or injection compression molding is performed between this mother mold and a fixed mold opposing it.

In addition, the mother mold is equipped with a heating element and a water-cooled cooling element, which suppresses the drop in transfer accuracy due to rapid curing during injection and controls the temperature of the mother mold to accelerate curing after a certain period of time. It is now possible to do so.

(Problem to be Solved by the Invention) By the way, when comparing the thermal expansion coefficients of nickel, which is the material of the stamper 1, for example, polycarbonate A fat and 5 the stamper, the former has a coefficient of 7. OX 10 = /'C, and the latter is 1°28X
10=/'C. For this reason, there will be a difference in the amount of shrinkage between the molding resin and the stamper as the temperature drops, but the temperature control of the matrix in the molding equipment described above simply sets heat generation and cooling, so the molding resin and The stamper undergoes a shrinkage process corresponding to its respective coefficient of thermal expansion.

Therefore, as shown in FIG. 4, when moving the master mold to open the mold, the difference in the amount of shrinkage between the stamper 50 and the disk 52 as the molded object causes a radially outward shift stress as indicated by the arrow R. This may result in abnormal transfer in which the right shoulder portion 54a of the bit 54 of the disk 52 has a bent shape. If the degree of abnormal transfer is severe, it may cause track misalignment, leading to a decline in product quality.
The bit forming protrusions and group forming protrusions formed on the disc 52 are shown, and 60 indicates the group transferred to the disk 52 by the group forming protrusions 58.

(Means for solving 11110) In order to solve the above-mentioned problem, the present invention monitors the temperature of the mother mold and the molded object throughout the shrinkage process of both.

It is designed to avoid the occurrence of shear stress by controlling the temperature of the mother mold so that the amount of shrinkage of each mold matches, and it is equipped with a stamper having a predetermined molding pattern surface and is capable of generating heat and cooling. In a precision mold molding device that performs injection molding between a set movable mother mold and a fixed mold opposing the mother mold, a temperature monitor detects the temperature of the mother mold and a molded object. temperature control for controlling the temperature of the mother mold throughout the shrinkage process so that the amount of shrinkage of the mother mold and the molded material coincides with each other as the temperature of the mold and the molded material decreases according to information from the temperature monitoring mechanism; It has a structure in which a mechanism is installed.

(Function) According to the present invention, during the contraction process of the mother mold and the molded object due to a temperature drop, the temperature monitoring mechanism grasps the respective temperature changes, and the grasped temperature change information is transmitted to the temperature control mechanism. Ru. The temperature control mechanism that receives the temperature change information controls the temperature of the mother mold throughout the shrinkage process so that the amount of contraction of the mother mold corresponds to the amount of shrinkage of the molded object.

(Example) FIG. 1 shows an embodiment of the invention.

A mother mold 2 is movably installed in the device main body (not shown), and a fixed mold 4 is installed opposite the burnt mother mold 2. An example is shown in which a polycarbonate resin as a thermoplastic resin is injected between a mother mold 2 and a fixed mold 4 to form a disc-shaped molded object 5 such as a compact disc. The mother mold 2 consists of a movable main body part 6, a temperature variable body 8 stacked on the front surface of the movable main body part 6, and a nickel stamper 10 formed to a thickness of 50 microns. The temperature variable body 8 and the stamper 10 are fixed to the movable main body part 6 with a presser 12.

The temperature variable body 8 includes a conductor main body 14 and a conductor main body 1
An insulating layer 16 installed to sandwich 4. It consists of I8. The insulating layer 16.18 is made of, for example, ZrO or TiO.
Made of grade 3 ceramics. The conductor main body part 14 is
As shown in FIG. 2, two types of annular conductors 20 with different diameters are used.
．． 22 are arranged concentrically in a contacting state alternately and having an area corresponding to the area of the back surface of the stamper 10. In this example, bismuth is used as the annular conductor 20 and antimony is used as the annular conductor 22. The temperature variable body 8 is connected to a power source 24, and the Peltier effect (P
It has a heat generating ability and a cooling ability based on e 1 t i e refect).

A pit forming protrusion 10a and a group forming protrusion 10b are formed on the surface of the stamper IO, and a transfer pattern surface for the object to be molded 5 is formed.

On the other hand, an injection hole 4a is formed in the fixed mold 4, and temperature detection elements 26 for detecting the temperature of the molded object 5 are arranged in a matrix on the bottom surface. Each temperature detection element 26 is connected to a first temperature detection section 30 of the temperature monitor mechanism 28.
The temperature change of the molded object 5 is horizontally compared by the first temperature detecting section 30 using the electromotive force value due to the thermal gradient between the adjacent temperature detecting elements 26 . Information detected by the first temperature detection section 30 is then transmitted to the temperature control mechanism 32.

Further, the temperature change of the stamper 10, that is, the temperature change of the mother mold 2, is detected by the second temperature detection section 34 of the temperature monitoring mechanism 28.
The detected information is detected by the temperature control mechanism 32.
is transmitted to. The second temperature detecting section 34 includes, for example, a plurality of temperature detecting elements (not shown) arranged in a matrix on the temperature variable body 8, and an amplifier to which these temperature detecting elements are connected.

The temperature distribution of the temperature variable body 8 can be grasped locally or block by block.

The temperature control mechanism 32 collates the information from the first temperature aspect ratio section 30 and the second temperature detection section 34, and controls the power supply 24 based on the collation result. By controlling the direction of the current, the reversibility of the Peltier effect of the heating capacity and cooling capacity in the temperature variable body 8 is obtained, and by controlling the current value, the temperature in the heating capacity and cooling capacity can be increased or decreased. Since the temperature variable body 8 corresponds to the entire back surface of the stamper 10, the local temperature gradient and the overall temperature gradient of the stamper 10 can be arbitrarily controlled by the temperature control mechanism 32. Note that the conductor main body portion 14 of the temperature variable body 8 can also have a structure in which two types of conductors, each having a cylinder shape or a cube shape, are arranged in a matrix.

As mentioned above, the thermal expansion coefficient of nickel is about 115 that of polycarbonate resin, so it is necessary to reduce the temperature on the standby 10 side by about 5 times that of the molded object 5, but this constant rule is maintained. The power supply 24 is controlled by the temperature control mechanism 32 so that the temperature is controlled.

In addition, the amount of displacement due to temperature change is Δ℃1 yuan is L,
If the coefficient of thermal expansion is α and the amount of change in temperature is ΔT, then ΔQ=
Since there is a relationship of LXα×ΔT, in order to suppress ΔΩ within a certain range, the temperature control mechanism 32 is provided with a logic circuit or a virtual table that can appropriately set ΔT according to the change in L, that is, the variation area and the length of the range. Built-in.

Therefore, the temperature of the matrix 2 is controlled throughout the shrinkage process so that the amount of shrinkage of the matrix 2 and the molded object 5 match as the temperature drops, so that the deviation due to the difference in the amount of shrinkage between the two is controlled. In addition to suppressing the generation of stress, it is also possible to suppress the occurrence of abnormal transcription.

Next, FIG. 3 shows another embodiment of the present invention, in which the same parts as in the previous embodiment are designated by the same reference numerals.

A temperature variable body 36 and a nickel stamper 38 having a molded pattern surface are installed in a stacked manner on the front surface of the movable main body 6. The temperature variable body 36 is made up of a main body 40 and a plurality of elements 42 having heating and cooling abilities, which are arranged and embedded in the main body 40, for example, in a matrix.

It is formed into a plate shape using a resin that has a higher melting point, glass transition point, and coefficient of thermal expansion than the injected resin. Further, the stamper 38 is formed in the form of a thin film with a thickness of 5 microns or less.

Since the stamper 38 is an ultra-thin film with no rigidity and the thermal characteristics of the temperature variable body 36 are similar to those of the object 5, the object 5 and the stamper 3 during the shrinking process are
8 is approximated, and the accuracy of suppressing shear stress by temperature control of the matrix 2 can be improved.

(Effects of the Invention) According to the present invention, it is possible to suppress the occurrence of shear stress, and therefore it is possible to suppress the deterioration in quality of the molded product due to abnormal transfer.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the main parts of a molding device using a precision mold according to an embodiment of the present invention, FIG. 2 is a plan view showing the main parts of the temperature variable body shown in FIG. 1, and FIG. FIG. 4 is a cross-sectional view of a main part showing an embodiment of the present invention, and FIG. 4 is a diagram showing a state of abnormal transfer. 2...Mother mold, 4...Fixed mold, 5...Molded object 8
．． 36... Temperature variable body, 10.38... Stamper 1
4... Main body part, 16.18... Insulating layer 20.22.
...Annular conductor, z4...Power supply, 40...Resin plate 42
...Element core 2 Diagram δ Diagram Horse diagram

Claims (1)

[Claims] 1. A movable mother mold equipped with a stamper having a predetermined molding pattern surface and configured to be able to generate heat and cool;
In a molding device using a precision mold that performs injection molding between a fixed mold facing the mother mold, a temperature monitoring mechanism for detecting the temperature of the mother mold and the molded object is installed, and the temperature monitoring mechanism Precision molding machine, characterized in that a temperature control mechanism is installed to control the temperature of the mother mold throughout the shrinkage process so that the amount of shrinkage of the mother mold and the molded object coincide with each other as the temperature drops. Molding equipment using molds.