JPH061622A - Method for working forming die of glass forming machine - Google Patents

Abstract

PURPOSE:To bind a releasable film firmly to the face of the forming die of a glass forming machine by etching and to smooth the surface. CONSTITUTION:When a releasable film 7 is formed on the faces 1a and 2a of forming dies 1 and 2, a work 12 is mounted on a table 11, gaseous methane is introduced into a chamber 10, the methane is decomposed by plasma to deposit carbon on the work 12, and a carbon film is formed. Argon gas is then introduced into the chamber 10 from an argon gas supplying source 14 and ionized by the plasma to form a carbon releasable film by plasma CVD, the film is plasma-etched by ion bombardment, hence the film is firmly attached to the surface of the work 12 by the implantation in etching, and the surface is smoothed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a release film on a mold surface of a glass molding machine for press-molding optical precision products such as lenses.

[0002]

2. Description of the Related Art In recent years, in manufacturing an optical precision product such as a lens, a press molding means has been developed and put into practical use instead of polishing. As a device for performing this press molding, a glass material is loaded between the upper and lower press molds that can be heated by heating means such as a heater, and both molds are heated in a non-pressurized state. After softening the glass material loaded inside, press molding is performed by applying a pressing force between the upper and lower molds. After this press molding is completed, the molding die is cooled, the upper die and the lower die are separated, and the press-formed product is taken out.

Here, a large pressing force acts on the molding die,
Moreover, since it is heated, it is possible to use only limited materials such as cemented carbide and fine ceramics.
For this reason, when the mold is brought into direct contact with the glass material, smooth sliding between the mold surface and the glass during pressurization is obstructed, and the releasability at the time of taking out the product from the mold after molding is poor, and the accuracy is high. It will not work well. For this purpose, a mold having a release film formed on the mold surface is used. As a method of forming this release film, a chemical vapor deposition method (C
The VD method) is often used.

[0004]

In a chemical film forming method such as the CVD method, it is not always possible to firmly adhere the mold surface and the release film. Since the mold can be operated under extremely severe conditions, such as applying a pressure force in a heated state, a chemically formed release film does not provide sufficient durability and is used for a long period of time. While doing so, there is a possibility that inconvenience such as peeling of the release film may occur. Also, the mold surface of the molding die is formed by polishing, but the polishing powder at the time of this polishing is not completely removed, and extremely fine foreign matter such as polishing powder, oil stains, etc. adhere to the mold surface. And the accuracy of the release film on the surface thereof is affected, and the adhesion of the release film to the mold surface becomes non-uniform, which may deteriorate the accuracy of press molding. . Furthermore, for example, when carbon is used for the release film, methane gas is usually decomposed by the action of plasma to adhere the carbon to the mold surface, but the problem is that the surface of the film is not always smooth. There is also.

The present invention has been made in order to solve the problems in the prior art as described above, and its object is to make a release film formed on the mold surface of a press mold extremely stable. In this state, the film is formed so as to be smooth.

[0006]

In order to achieve the above-mentioned object, according to the present invention, a glass material is loaded between a pair of press molding dies, and the glass material is heated and softened. A method for forming a release film on a mold surface of a mold of a glass molding machine for performing a molding by applying a pressure force between the molds, which comprises laminating a release film on the mold surface, The feature is that the mold film is ionically etched.

[0007]

Operation: First, a release film is formed on the mold surface of the mold. This release film can be formed by an appropriate means, and can be formed by a chemical method such as a CVD method or another method. However, the stability of the release film cannot be obtained only by performing this chemical film forming method. Therefore, after film formation,
Etching is performed by accelerating and colliding with the release film. As a result, the release film is etched and punched into the mold surface and firmly fixed, and the surface is finished to be smooth and uniform.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. First, the configuration of the glass molding machine will be described with reference to FIG. In the figure, 1 is a lower mold, 2 is an upper mold, 3 is a body mold, respectively, and a mold in which the upper surface of the lower mold 1 and the lower surface of the upper mold 2 are finished along the outer shape of the molded product, respectively. Surface 1
a and 2a. Then, the upper and lower molds 1,
The glass material 4 is loaded between the two mold surfaces 1a and 2a. A heater 5 is mounted around the body mold 3, and the heater 5 is operated with the glass material 4 loaded to heat the molding dies 1 and 2 to soften the glass material 4. The lower mold 1 is moved up along the body mold 3 or the upper mold 2 is moved down to hold the opponent mold fixed to the movable mold. As a result, the glass material 4 is pressure-molded. When this press molding is completed, the molded product can be taken out after cooling the glass material 4.

In the glass molding machine configured as described above, in order to improve the processing accuracy, both molding dies 1,
The mold releasability of the second mold surfaces 1a and 2a must be good. However, the molding dies 1 and 2 must be formed of members such as cemented carbide and fine ceramics in consideration of weight and strength against heat. Therefore, the mold releasability of the molding dies 1 and 2 itself is not good. Therefore, as shown enlarged in FIG. 2, a release film 7 is formed on the surfaces of the mold surfaces 1a and 2a of the molding dies 1 and 2.

The release film 7 is formed by using the film forming apparatus shown in FIG. In the figure, reference numeral 10 denotes a chamber, and a table 11 is provided in the chamber 10, and a work 12 composed of molding dies 1 and 2 is installed in the table 11. As shown in FIG. 4, the work 12 is mounted in the recess 11a formed in the table 11. Thus, when the work 12 is mounted in the recess 11a of the table 11, the upper surface of the work 12 is at a height position substantially matching the surface of the table 11, and the gap between the recess 11a and the work 12 is extremely small. It is set to be small. As a result, the work 12 becomes continuous with the surface of the table 11, and the work 12 can have a structure having substantially no edge portion.

On the work 12, the release film 7 is formed in the chamber 10, and then the release film 7 is etched. For this purpose, the methane gas (CH ₄ gas) supply unit 13 and the argon gas supply unit 14 are provided, and the pipes 15 and 16 from the methane gas supply unit 13 and the argon gas supply unit 14 join together on the way. It serves as a supply pipe 17 and is connected to the chamber 10. The valve opening of each of the pipes 15 and 16 is 0 (that is, the closed state).
Flow control valve 1 that can control the flow rate from open to fully open
8 and 19 are provided, and the gas supply pipe 17 is provided with an opening / closing valve 20. Here, the chamber 10 is decompressed. To this end, the chamber 10
A suction pipe 21 is connected to the suction pipe 21.
A mechanical booster pump 22 and a rotary pump 23 are connected to the. Further, a heater 24 that heats the work 12 is mounted on the table 11, and a high frequency power supply 25 that supplies high frequency power is connected to the table 11.
In the figure, 26 is a pressure gauge for measuring the pressure inside the chamber 10.

Therefore, a method for forming a film on the work 12 using the film forming apparatus will be described below. First, the work 12 is mounted on the table 11, and the rotary pump 23
Also, the mechanical booster pump 22 is operated to reduce the pressure in the chamber 10. When the pressure gauge 26 brings the inside of the chamber 10 to a predetermined pressure state, methane gas is supplied from the methane gas supply unit 13. At the same time, the heater 24 provided on the table 11 is operated to operate the work 12
Is heated and high-frequency power is supplied from the high-frequency power supply 25 to generate plasma between the table 11 and the upper electrode 27. Then, the methane gas supplied into the chamber 10 causes a decomposition reaction due to the action of plasma, deposits carbon on the surface of the work 12, and forms this carbon film. That is, the carbon release film is formed by the plasma CVD method.

When the carbon release film has a predetermined film thickness, the supply of gas into the chamber 10 is stopped by closing the on-off valve 20, and in this state, the methane gas in the chamber 10 is removed by the rotary pump 23. Discharge. After that, the argon gas is supplied from the argon gas supply unit 14 into the chamber 10. The high frequency power supply 25 may be kept in the operating state even when the gas is replaced, or the operation may be stopped when the gas is replaced. The argon gas supplied into the chamber 10 is ionized by the action of plasma and accelerated in the plasma sheath shown by the dotted line in FIG. 4, so that the carbon release film formed by the plasma CVD method is Plasma etching using ion bombardment is performed. The carbon release film is firmly fixed to the surface of the work 12 by the implantation action during the etching, and
The surface will be smoothed.

In this way, after the carbon release film is formed by the plasma CVD method, the surface accuracy of the release film is improved by performing the plasma etching treatment on the carbon release film. The strength will be improved. As a result, when the work 12 is used as the lower mold 1 and the upper mold 2 of the press molding machine for performing the press molding of the glass material 4, the mold release film 7 formed on the mold surfaces 1a, 2a of the both molds 1, 2. By the action, the sliding property at the time of molding and the releasability at the time of taking out the molded product from the molding die are improved, the glass material 4 can be press-molded with extremely high accuracy, and the processing accuracy can be improved by observing the interference fringes. When I inspected
There is no fear that the interference fringes will be disturbed, and the surface accuracy of the molded product can be significantly improved. Further, the mold can be operated under extremely harsh conditions such as applying a pressure force in a heated state.
The binding strength with the mold surface is improved, and even if some foreign matter or dirt adheres to the mold surface, the strength of the release film becomes uniform and no partial decrease in strength occurs. . Therefore,
A stable operation can be performed over a long period of time.

Although the carbon release film is used in the above-mentioned embodiments, a release film of, for example, boron nitride may be formed in addition to the carbon release film. When this release film is formed, a boron compound gas and a nitriding gas may be supplied to the chamber. Also,
The etching was performed using argon gas,
Other than this, it is also possible to use an inert gas such as helium, neon, or xenon.

[0016]

As described above, according to the present invention, the mold release film is formed on the mold surface of the molding die, and the mold release film is subjected to ion-engineering etching. The binding strength to the mold surface is remarkably improved, a uniform binding force can be exerted, and the release film surface becomes smoother. As a result, in press-molding a precision optical product from a glass material, the molding accuracy is remarkably improved, the yield of the product is improved, and the life of the molding die is extended.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a configuration of a glass molding machine.

FIG. 2 is an enlarged sectional view of a main part of a molding die.

FIG. 3 is an explanatory diagram of a configuration of a film forming processing apparatus.

FIG. 4 is a sectional view of a table on which a work is installed.

[Explanation of symbols]

 1 Lower Mold 2 Upper Mold 1a, 2a Mold Surface 4 Glass Material 10 Chamber 11 Table 11a Recess 12 Work 13 Methane Gas Supply Section 14 Argon Gas Supply Section 25 High Frequency Power Supply

Claims (3)

[Claims] 1. A glass for forming a glass material by loading a glass material between a pair of press molding dies, and applying a pressure between the press molding dies while the glass material is heated and softened. A method for forming a mold release film on a mold surface of a molding die of a molding machine, characterized in that a mold release film is laminated on the mold surface, and then the mold release film is ionically etched. Mold forming method for glass molding machine. 2. The molding die processing method for a glass molding machine according to claim 1, wherein the release film is laminated by a chemical vapor deposition method, and the etching is performed by sputter etching. 3. A methane gas is supplied into the chamber, the methane gas is decomposed by the action of plasma, a carbon release film is laminated on the mold surface, and then methane gas is produced from the chamber, and then argon gas is supplied into the chamber. 2. The method for processing a mold according to claim 1, wherein the carbon mold release film is etched by ionizing argon atoms to ionize the carbon mold release film, and the carbon mold release film is driven into the mold surface.