JP2002104831A - Press molding method - Google Patents

Abstract

(57) [Problem] To provide a press forming method capable of appropriately performing press forming of a quartz glass substrate. A press forming method for forming a V-groove on a surface (22a) of a quartz glass substrate material (22) by press molding is in a transformation region where the quartz glass substrate material (22) can be press-formed in a heating furnace (20). A heating step of heating to 1400 ° C. or more to soften, and holding the temperature of the softened quartz glass substrate material 22 within the temperature range of its transformation region to mold the quartz glass substrate material 22 into a mold 4,
5, a pressing step of forming a V-groove by pressing, and a releasing step of separating the pressed quartz glass substrate with the V-groove from the dies 4 and 5 in a heating step. The heating time for increasing the temperature to the press molding temperature is 10 minutes or more, the pressing time in the pressing step is 1 minute or more, and the temperature at the time of releasing in the releasing step is 700 ° C. or more.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press forming method suitable for manufacturing a product such as a glass substrate having a plurality of V-grooves formed on a surface used for fixing an optical fiber or the like by press forming. It is about.

[0002]

2. Description of the Related Art A glass substrate having a large number of V-grooves formed on its surface is used, for example, to form a fiber array in which optical fibers are arranged in each V-groove and a cover glass is laminated. I have. Such a V-groove glass substrate is manufactured, for example, by grinding a flat glass substrate surface to form a V-groove.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to propose a press forming method capable of efficiently producing such a processed product such as a V-groove glass substrate from a plate material such as quartz glass by press forming. is there.

[0004]

According to the present invention, there is provided a method for press-forming quartz glass according to the present invention comprising: a step of forming a transformed region in which quartz glass can be press-formed;
A heating step of heating to a temperature of at least ℃ and softening; a pressing step of pressing the softened quartz glass while maintaining the temperature of the softened quartz glass within a temperature range of its transformation region; A heating time for raising the quartz glass from a normal temperature state to the molding temperature in the heating step is 10 minutes or more; a pressing time in the pressing step is 1 minute or more; Wherein the temperature at the time of mold release is set to 700 ° C. or more; and each of the steps is performed in a vacuum atmosphere, an inert gas atmosphere, or the air.

[0005] By following such processing conditions, it becomes possible to press-form V-grooves and the like on the surface of quartz glass.

Here, it is desirable to apply ultrasonic vibration to the mold in at least the pressing step of the pressing step and the releasing step. By applying the ultrasonic vibration to the mold, the pressing force of the mold required for performing the desired press molding can be reduced. Further, the quartz glass after the press molding can be easily released from the mold.

In the heating step, it is desirable that the quartz glass be heated without being brought into contact with the mold. If the quartz glass is heated while being in contact with the mold, the quartz glass is activated by the heating and reacts with the metal surface of the mold to come into close contact with the surface, making it difficult to release the mold.

Further, it is desirable that the pressing step is performed in a state where the mold surface temperature is lower than the quartz glass surface temperature. As described above, when the mold surface temperature is lower than the quartz glass surface temperature, it is possible to prevent the quartz glass from sticking to the mold surface, and the mold is easily released.

Further, in the releasing step, the press-formed surface of the quartz glass is turned upward, and the quartz temperature is set to 1300 ° C.
It is preferable to release the quartz glass by pushing up the quartz glass from the lower mold while the temperature is within the range of 1400 ° C. to 1400 ° C. That is, after the press molding, the quartz glass and the mold have different shrinkage rates upon cooling, so that it is desirable to release the mold within the above temperature range. Further, if the quartz glass is pushed up from the side opposite to the press-formed surface of the quartz glass, the die cutting operation can be easily performed.

Next, the present invention relates to a press forming method in which a work in a solid state at normal temperature is heated to a forming temperature at which the work is in a softened state capable of being press-formed, and pressing is performed in this state. After being heated to the temperature, the workpiece is press-formed while applying ultrasonic vibration to the mold.

[0011] The present invention also provides a press forming method in which a work in a solid state at normal temperature is heated to a forming temperature at which the work becomes a softened state capable of being press-formed and pressed in this state. It is characterized in that the workpiece is held so as not to be brought into contact, and the workpiece is heated to the molding temperature in this state.

Further, the present invention provides a press forming method in which a work in a solid state at normal temperature is heated to a forming temperature at which the work becomes a softened state capable of being press-formed, and the work is pressed in this state. In addition, the temperature of the mold is controlled to be lower than the temperature of the workpiece.

Further, the present invention provides a press forming method in which a work in a solid state at normal temperature is heated to a forming temperature at which the work becomes a softened state capable of being press-formed, and pressing is performed in this state. It is characterized in that press molding is performed with the surface facing upward, and after pressing, the workpiece is pushed upward from the lower mold.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a press forming method according to the present invention will be described with reference to the drawings.

(Structure of Press Forming Machine) FIG. 1 is a schematic structural view of a quartz glass press forming machine of this embodiment, and FIG. 2 is a perspective view showing a press-formed glass substrate having a V-shaped groove.
FIG. 3 is an explanatory diagram showing a state immediately before pressing. First, as shown in FIG. 2, a press-formed glass substrate 2 with a V-groove has a shape in which a plurality of V-grooves 21a are formed in parallel at a constant pitch on the surface of a rectangular quartz glass substrate 21 having a constant thickness. Things.

As shown in FIG. 1, the press forming machine 1 includes a rectangular work support frame 3 disposed in a heating furnace 20, and the work support frame 3 is a rectangular quartz having a constant thickness. This is for supporting the glass substrate material 22 horizontally. An upper die 4 is disposed directly above the work support frame 3.
Immediately below the lower mold 5 is arranged. The upper die 4 is a press-molding die, and an uneven surface 4a for forming a V-groove is formed on the lower surface thereof. The upper surface of the lower die 5 is a flat surface 5a for supporting a work. Therefore, the upper surface 22a of the quartz glass substrate material 22 is a press-formed surface, and a large number of V-grooves are press-formed here.

The upper mold 4 and the lower mold 5 are configured to be driven vertically by a known hydraulic drive mechanism 6. The hydraulic drive mechanism 6 is driven by the control device 7. An eject pin 8 vertically penetrates the lower die 5 so as to be movable in the vertical direction, and the eject pin 8 is also driven by a known hydraulic drive mechanism 6.

Further, ultrasonic oscillators 11 and 12 are attached to the upper mold 4 and the lower mold 5, respectively, so that ultrasonic vibration can be given to each of the upper mold 4 and the lower mold 5. . These ultrasonic oscillators 1
The drive control of 1 and 12 is also performed by the control device 7.

In addition, in this embodiment, a temperature control means for managing the surface temperatures of the upper mold 4 and the lower mold 5 is provided. The temperature control means of this example is provided inside the molds 4 and 5.
Cooling water circulation paths 13 and 14 are provided, and a refrigerant such as cooling water is configured to circulate from a refrigerant source 15 through these circulation paths 13 and 14. The circulation control of the refrigerant is performed by the control device 7, whereby the upper die 4, the lower die 5
Temperature control of the surfaces 4a, 5a.

(Press Forming Operation) A procedure for producing a glass substrate 2 with a V-groove shown in FIG. 2 by press forming the quartz glass substrate material 22 by the press forming machine 1 having the above-described configuration will be described.

First, as shown in FIG. 1, a quartz glass substrate material 22 is placed on a work supporting frame 3 in a heating furnace 20. In this state, the inside of the heating furnace 20 is heated, and the quartz glass substrate material 22 is heated until it reaches the temperature range of the transformation region in which press molding is possible. For example, heating is performed until the temperature becomes 1400 ° C. or higher. When the quartz glass substrate material 22 is heated to the temperature range of the transformation region, the quartz glass substrate material 22 is in a state near the softening point, and is in a press forming temperature state where press forming is possible (heating step).

After the quartz glass substrate material 22 reaches the press molding temperature, the temperature state is maintained and the hydraulic drive mechanism 6
The lower mold 5 is moved by the back surface 22 b of the quartz glass substrate material 22.
The upper mold 4 is lowered in this state, and the surface 2 of the quartz glass substrate material 22 is lowered.
A V-groove is press-formed in 2a (pressing step). FIG. 3 shows the positional relationship between the quartz glass substrate material 22, the upper mold 4 and the lower mold 5 immediately before pressing.

The upper mold 4 is pressed against the surface 22a of the quartz glass substrate material 22 with a predetermined pressing force, and after the state is continued for a predetermined time, the upper mold 4 is pulled up to the retreat position and the mold is opened. Thereafter, the eject pin 8 is driven to protrude from the upper surface 5a of the lower die 5, and the press-formed quartz glass substrate 2 with the V-groove is peeled off from the lower die surface 5a (release step).

Thus, the quartz glass substrate 2 having the V-grooves 21a press-formed on the surface as shown in FIG. 2 can be obtained. Here, in the present example, the heating time for raising the quartz glass from the normal temperature state to the molding temperature in the heating step is set to 10 minutes or more, and the quartz glass substrate material 22 is heated in an appropriate state to the transformation region. Also,
Press duration in the pressing process is 1 minute or more,
V-grooves can be press-formed with high accuracy. Further, when the quartz glass substrate 2 is released from the lower mold 5 at a temperature of 700 ° C. or more (in this example, in a range of 1300 ° C. to 1400 ° C.), the quartz glass substrate may be broken due to a difference in heat shrinkage. The evil is avoided. The heating furnace 20 is
It may be a vacuum atmosphere or an inert gas atmosphere,
It may be an air atmosphere.

Here, in the pressing step of this embodiment, the ultrasonic oscillators 11 and 12 are driven by the control device 7 during the pressing by the upper die 4, and ultrasonic vibration is applied to the upper die 4 and the lower die 5. Have been. Ultrasonic vibration may be applied only to the upper mold 4. As described above, by applying ultrasonic vibration to the mold at the time of pressing, the pressing force required for press molding by the molds 4 and 5 can be reduced, and the mold release is facilitated. As a result, the life of the dies 4 and 5 can be extended.

Next, in this example, in the heating step, the quartz glass substrate material 22 is heated without being brought into contact with the dies 4 and 5. As a result, the time during which the quartz glass substrate material 22 contacts the dies 4 and 5 is short for press molding. As described above, when the contact time between the quartz glass substrate in a high temperature state and the molds 4 and 5 is shortened, it is possible to prevent the quartz glass substrate material 22 from sticking to the mold surface.

In addition, in this embodiment, the surface temperature of the dies 4 and 5 is controlled under the control of the control device 7 so that the temperature of the dies 4a and 5a is reduced by quartz during press molding. The temperature is set lower than the surface temperature of the glass substrate material 22. That is, through the heating process and the pressing process,
Refrigerant such as cooling water is circulated through the cooling water circulation paths 13 and 14 so that the dies 4 and 5 have a lower temperature than the quartz glass substrate material 22. For example, control is performed so that a temperature difference of about several hundred degrees is obtained.

When the pressing is performed in such a state where the temperature difference is provided, the sticking of the quartz glass substrate 2 to the mold surfaces 4a, 5a can be avoided. Therefore, there is an advantage that the releasing operation is simplified.

Further, in the present embodiment, as described above, at the time of release, the eject glass 8 pushes up the quartz glass substrate 2 on which the press-formed surface 22a is arranged upward. This ejection operation is performed while the quartz glass temperature is in the range of 1300 ° C. to 1400 ° C. In such a temperature state, the mold release can be easily performed.

In the press molding machine 1 of this embodiment, the quartz glass substrate material, which is a workpiece, is heated in a non-contact state with the mold so that the surface of the mold becomes lower in temperature than the quartz glass substrate material. The heating temperature is controlled, and ultrasonic vibration is applied to the mold during pressing. However, the invention is not intended to employ all of these methods.
Methods using these alone or in combination are also included in the scope of the present invention.

In the above example, quartz glass is taken as an example of a workpiece, but the workpiece is not limited to quartz glass. The method of the present invention can be applied to any material that is solid in a normal temperature state and becomes a softened state that can be press-formed when heated to a predetermined temperature.

[0032]

As described above, according to the press forming method of the present invention, the press forming of quartz glass can be suitably performed.

Further, in the press molding method of the present invention, since the ultrasonic vibration is applied to the mold at the time of pressing, the pressing force required for press molding can be reduced, and the press molded product can be easily released. Become.

Further, in the press molding method of the present invention, since the workpiece is heated to the press molding temperature in a state where the workpiece does not come into contact with the mold, the workpiece heated to a high temperature is stuck to the mold and released. Can be avoided.

Further, in the press molding method of the present invention, the mold surface temperature is controlled so as to be lower than the heating temperature of the workpiece to be press-molded, so that the press-molded product can be easily released. Become.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a press molding machine to which a method of the present invention is applied.

FIG. 2 is a perspective view showing a quartz glass substrate with a V-groove formed by the press forming machine of FIG. 1;

FIG. 3 is an explanatory diagram showing a state immediately before pressing in the press molding machine in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Press molding machine 2 Quartz glass substrate with V groove 21 Substrate 21a V groove 22 Quartz glass substrate material 22a Press molding surface 22b Back surface 3 Work support frame 4 Upper die 5 Lower die 6 Hydraulic drive mechanism 7 Control device 8 Eject pin 11, 12 Ultrasonic oscillator 13, 14 Cooling water circuit 15 Refrigerant source 20 Heating furnace

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[Procedure amendment]

[Submission Date] October 4, 2000 (2000.10.
4)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 3

Claims (9)

[Claims] 1. A heating step of heating quartz glass to a temperature of 1400 ° C. or more to be in a transformation region capable of being press-molded to soften the quartz glass, and maintaining a temperature of the softened quartz glass within a temperature range of the transformation region. A pressing step of pressing the quartz glass with a mold, and a releasing step of separating the pressed quartz glass from the mold. In the heating step, a heating time for raising the quartz glass from a normal temperature state to the molding temperature is 10 minutes. The pressing time in the pressing step is 1 minute or more, the temperature at the time of releasing in the releasing step is 700 ° C. or more, and the respective steps are performed in a vacuum atmosphere, an inert gas atmosphere, or an air atmosphere. A press molding method for quartz glass, which is performed. 2. The method of press-forming quartz glass according to claim 1, wherein an ultrasonic vibration is applied to a mold in at least the pressing step of the pressing step and the releasing step. 3. The method according to claim 1, wherein in the heating step, the quartz glass is heated without being brought into contact with a mold. 4. The press molding of quartz glass according to claim 1, wherein the pressing step is performed in a state in which a mold surface temperature is lower than a quartz glass surface temperature. Method. 5. The mold release step according to claim 1, wherein the press-molded surface of the quartz glass is directed upward and the quartz temperature is in a range of 1300 ° C. to 1400 ° C. And press-releasing the quartz glass by pushing up the quartz glass from a lower mold. 6. A press forming method in which a work in a solid state at normal temperature is heated to a forming temperature at which a softened state capable of press forming is performed, and pressing is performed in this state, wherein the work is heated to the forming temperature. After that, a press forming method characterized by press-forming the workpiece while applying ultrasonic vibration to the mold. 7. A press-forming method in which a work in a solid state at room temperature is heated to a forming temperature at which a softened state that can be press-formed is formed, and the work is pressed in this state so that the work is not brought into contact with a mold. A press molding method, wherein the workpiece is held and heated to the molding temperature in this state. 8. A press-forming method in which a work in a solid state at normal temperature is heated to a forming temperature at which the work becomes a softened state capable of being press-formed, and the work is pressed in this state. A press molding method characterized by controlling the temperature of a mold to be lower than the temperature of an object. 9. A press forming method in which a work in a solid state at normal temperature is heated to a forming temperature at which the work is in a softened state capable of being press-formed, and pressing is performed in this state, wherein the press-formed surface of the work is directed upward. Press-forming method in which the workpiece is pressed upward from a lower mold after pressing.