JP2002326824A - Apparatus for press molding of glass - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for press molding of glass able to recover easily a product from a mold without flaw after finishing molding. SOLUTION: A lower molding unit 11 consists of a die plate 12, plural lower molding cores 13, a cavity die 14 and a slide plate 15. The cavity die 14 has plural first apertures 14a on the upper face side and a second aperture 14b on the lower face side. Each first aperture 14a is connected to the second aperture 14b. Each lower molding core 13 is set in each first aperture 14a. The side plate 15 is set in the second aperture 14b and supports the back side of each lower molding core 13. A through-hole 12a is penetrated at the die plate 12 and the top of an ejector rod 17 is housed in it. The ejector rod 17 can be moved to upper and lower directions and assembled in a transparent shaft 9 of the apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press forming apparatus for producing a glass molded product such as an optical lens or a prism, and more particularly to a mechanism for removing a product after press molding from a mold. About.

[0002]

2. Description of the Related Art In addition to polishing, glass optical elements such as optical lenses and prisms that require high precision are also manufactured by a method generally called a reheat press molding method. In the reheat press molding method, a raw material glass is once melted and solidified in a mold to produce a molding material (preform) having a predetermined rough shape, and then the molding material is heated again. This is a method of manufacturing an optical element by transferring the shape of a mold surface to glass by press molding.

[0003] This reheat press molding method has an advantage that the process required for forming a curved surface is only one step of press molding, and the productivity is high. Further, since there is no polishing step, the optical element can be manufactured in a clean environment. Further, once the mold is manufactured, it is possible to efficiently manufacture a large number of molded products according to the accuracy of the mold.

For example, when press molding an optical lens, if the upper and lower optical surfaces and the side surfaces of the lens are simultaneously molded, the pressing and cooling steps are completed, and after the upper and lower molds are opened, the lower surface is opened using a vacuum chuck or the like. The molded product is removed from the mold. However, since the molded product is embedded in the cavity of the lower mold, there is a problem that it is difficult to remove the molded product. For this reason, there have been problems such as a longer time required for collecting the molded product and a complicated structure of a device for supplying the raw material and the molded product.

[0005] A method of extruding a molded product with an ejector pin has also been adopted, as in an injection molding machine. However, in this case, since the ejector pins directly contact the optical surface of the molded product, there is a possibility that the molded product may be damaged or cracked.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems in the conventional press forming of glass, and an object of the present invention is to provide a product after press forming into a mold. An object of the present invention is to provide a glass press forming apparatus having a structure that can be easily taken out from the inside.

[0007]

According to the present invention, there is provided a press forming apparatus for glass, comprising a glass forming material between an upper mold supported by an upper shaft from the back side and a lower mold supported by a lower shaft from the back side. After heating the upper mold, the lower mold and the molding material, the upper mold or the lower spindle is driven to perform press molding, and in the glass press molding apparatus, the lower mold has a molding surface formed on a front surface. A core, a cavity die that surrounds the outer periphery of the core and guides the core from the outer periphery side, and a die plate that supports the core and the cavity die from the back side, wherein the die plate has a through hole vertically penetrating therethrough. Formed inside the lower shaft, a protruding rod whose tip portion is housed in the through hole and can be driven in the vertical direction is incorporated, and by using the protruding rod to push up the core, press forming is performed. Characterized in that it is composed of products to push out of the cavity die.

According to the press forming apparatus for glass of the present invention, after the pressing and cooling steps are completed, the upper and lower dies are opened, and then the protruding rod is driven to push up the core, so that the product after press forming is obtained. Can be taken out of the cavity die. This makes it possible to easily recover the molded product from the molding device using, for example, an automatic transfer device.

By mounting a plurality of cores on the upper and lower molds, a plurality of molded products can be manufactured at the same time.

In this case, it is preferable that the lower mold has a plurality of cores each having a molding surface formed on a front surface, a plurality of first openings formed on a front surface side, and a plurality of first openings formed on a back surface side. Two second openings are formed, a cavity die that guides each of the cores from the outer peripheral side on the inner peripheral surface of the first opening, and is accommodated inside the second opening and supports each of the cores from the back side. And a die plate for supporting the slide plate and the cavity die from the back side. The die plate is formed with a through-hole penetrating vertically, and a tip portion is formed inside the lower shaft. A protruding rod that is housed in the through hole and can be driven vertically is incorporated, and by using the protruding rod, the cores are pushed up through the slide plate,
The product after the press molding is configured to be extruded from the cavity die.

In the above structure, the upper mold is constituted by the same core, cavity die and die plate (and slide plate) as above, and a protruding rod is incorporated into the upper shaft, instead of the lower mold. The protruding rod may be used to push down the cores (each core).

[0012]

FIG. 1 shows an example of a press forming apparatus for glass according to the present invention. In the figure, 2 is a fixed shaft (upper shaft), 4 is an upper mold unit (upper mold), 9 is a moving shaft (lower shaft), 11 is a lower mold unit (lower mold), 17 is a protruding rod, and 50 is a molding material. Represents

The fixed shaft 2 extends downward from the upper portion of the frame 1. An upper unit 4 is attached to the lower end of the fixed shaft 2 via a heat insulating cylinder 3 made of ceramic. A driving device 8 is disposed below the frame 1, and a moving shaft 9 is attached to the driving device 8. Moving axis 9
Penetrates the intermediate plate 31 of the frame 1 and
And extends upwardly. A lower mold unit 11 is attached to the upper end of the moving shaft 9 via a heat insulating cylinder 10. The upper unit 4 and the lower unit 1
Details of the structure 1 will be described later with reference to another drawing.

A protruding rod 17 that can be driven up and down is incorporated in the moving shaft 9. Protruding rod 17
Penetrates the center of the heat insulating cylinder 10, and the tip of the protruding rod 17 reaches the inside of the lower mold unit 11. The protruding rod 17 is driven up and down by an air cylinder 18 connected to a lower end thereof.

The upper mold unit 4, the lower mold unit 11, and the upper and lower heat insulating cylinders 3, 10 are housed in a transparent quartz tube 21. An upper plate 32 is mounted around the lower end of the fixed shaft 1, and a lower plate 33 is mounted around the upper end of the moving shaft 7. The lower plate 33 is supported on the intermediate plate 31. An O-ring is attached to a contact surface between the upper end surface of the transparent quartz tube 21 and the upper plate 32, thereby sealing the contact surface. Similarly, an O-ring is also attached to the contact surface between the lower end surface of the transparent quartz tube 21 and the lower plate 33, whereby the contact surface is sealed. By these, the quartz tube 21
Inside, a molding chamber 22 whose atmosphere can be adjusted is formed.

An infrared lamp unit 23 is arranged so as to surround the periphery of the quartz tube 21. The infrared lamp unit 23 includes an infrared lamp, a reflection mirror, and the like.

The transparent quartz tube 21 and the infrared lamp unit 23 are suspended from the lower surface of the upper plate 32. When supplying the molding material into the mold and when collecting the molded product from the mold, a driving device (not shown)
Is used to move the upper plate 32 upward, and the transparent quartz tube 21 and the infrared lamp unit 23 are retracted upward.

A load cell 37 is inserted into the connection between the driving device 8 and the moving shaft 9. A thermocouple 38 is attached to the lower mold unit 11. The output signals of the load cell 37 and the thermocouple 38 are sent to the control unit 36.
The control unit 36 controls the driving mechanism 8, the lamp unit 23 and others based on these output signals.

FIG. 2 is an enlarged view of the upper mold unit 4 and the lower mold unit 11. In the figure, 5 is a die plate,
6 is an upper mold core, 7 is a cavity die, 12 is a die plate, 13 is a lower mold core (core), 14 is a cavity die,
14a is a first opening, 14b is a second opening, 15 is a slide plate, 17 is a stick, and 50 is a molding material.

The upper die unit 4 includes a metal die plate 5, a plurality of ceramic upper die cores 6, and a metal cavity die 7. Cavity die 7
Is provided with a plurality of openings 7a. Each upper die core 6 is mounted in each of these openings 7a. The cavity die 7 is fixed to the lower surface of the die plate 5,
Each upper core 6 is supported from its periphery. Upper die core 6
Has a lower surface than the front surface of the cavity die 7.

The lower mold unit 11 includes a metal die plate 12, a plurality of ceramic lower mold cores 13, a metal cavity die 14, and a slide plate 15.

The cavity die 14 has a plurality of openings 14a (referred to as first openings) on the front side and one opening 14b (referred to as second openings) on the back side. . The inside of each first opening 14a communicates with the second opening 14b. Each lower die core 13 is mounted in each first opening 14. The slide plate 15 is mounted in the second opening 14b, and supports each lower mold core 13 from the back side. The cavity die 14 is a die plate 1
2 is fixed to the upper surface.

The lower core 13 can slide up and down along the inner peripheral surface of the first opening 14a of the cavity die 14. Similarly, the slide plate 15 extends along the inner peripheral surface of the second opening 14 b of the cavity die 14.
It can slide up and down. Slide plate 1
5 is in contact with the upper surface of the die plate 12 (that is,
When the lower die 13 is at the lower limit, the molding surface of the lower die core 13 is retreated below the front surface of the cavity die 14. The inner peripheral surface of the first opening 14a forms a side surface of the mold surface.

In order to align the axes of the upper die unit 4 and the lower die unit 11, two guide pins 7c are embedded in the cavity die 7 of the upper die unit 4 along the peripheral edge thereof. Guide holes 14 are provided at positions corresponding to the respective guide pins 7c at the peripheral portion of the cavity die 14.
c is provided.

In the center of the die plate 12, a through-hole 12a is formed which penetrates vertically. As mentioned above,
A protruding rod 17 that can move in the vertical direction is incorporated in the moving shaft 9 (FIG. 1). This stick 17
Of the through hole 1 provided in the die plate 12
2a.

The process of manufacturing an optical lens using the glass press forming apparatus shown in FIG. 1 will be described with reference to FIGS.

FIG. 2 shows the state of the upper mold unit 4, the lower mold unit 11, and the molding material 50 immediately before the start of press molding. A gob-shaped preform is used for the molding material 50. After setting the molding material 50 on each lower mold core 13, the upper and lower molds 4, 11 are brought as close as possible. In this state, the infrared lamp unit 23 (FIG. 1) is supplied while flowing an inert gas into the molding chamber 22 (FIG. 1).
Is used to heat the upper and lower dies 4, 11 and the molding material 50.

After the molding material 50 reaches a predetermined temperature and stabilizes, the moving shaft 9 (FIG. 1) is advanced to move the front surface of the lower cavity die 14 to the upper cavity die as shown in FIG. Press against the front of die 7. As a result, the molding material 50 is press-molded in the cavity surrounded by the molding surfaces of the upper die core 6 and the lower die core 13 and the inner peripheral surface of the first opening 14a of the cavity die 14.

After the completion of the press molding, an inert gas is flowed into the molding chamber 22 with the mold closed, thereby cooling the upper and lower dies 4, 11 and the molded product. After the molded article has cooled to a predetermined temperature, the moving shaft 9 is retracted and the mold is opened. next,
The protruding rod 17 is driven to push up the slide plate 15.

As a result, as shown in FIG. 4, the lower mold core 13 is pushed up along the inner periphery of the first opening 14a of the cavity die 14, and the molded product is pushed out of the cavity die 14. Since the upper unit 4 is retracted upward, it is omitted in FIG.

In the above-described example, the mold has a structure in which the molded product remains in the lower mold, but may have a structure in which the molded product remains in the upper mold. In this case, a molded article can be taken out by providing an ejector mechanism on the upper mold side and pushing up the upper mold core.

Next, an example in which an optical lens is manufactured by using the glass press forming apparatus of the present invention will be described.

The following glass preforms were used.

Manufacturer: OHARA CORPORATION Name: L-BAL42 Moving point: 506 ° C. Breaking point: 538 ° C. Shape: gob (0.9 g) FIG. The outline of the program for setting the temperature and press load at this time is shown below.

Using the above program, an aspherical biconvex lens having a diameter of 13 mm was formed. The lens accuracy at this time is as follows.

・ Surface accuracy of upper and lower optical surfaces: about λ / 8 ・ Concentricity of upper and lower optical surfaces: within 1 μm ・ Parallelism of upper and lower optical surfaces: within 15 sec ・ Dimensional accuracy of outer peripheral portion: within ± 0.01 mm Thickness accuracy: within ± 0.01 mm After press molding is completed, the molded product is easily taken out of the cavity die 14 by pushing up the lower die core 13 using the protruding rod 17 according to the procedure described above. I was able to. In addition, no flaw was generated in the removed molded article.

[0037]

According to the press molding apparatus for glass of the present invention, the product after the completion of molding can be easily taken out of the mold, and there is no possibility of damaging the product. Therefore, according to the glass press forming apparatus of the present invention, the structure of the automatic product transfer mechanism can be simplified, and the productivity of the apparatus can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a press forming apparatus for glass of the present invention.

FIG. 2 is an enlarged sectional view of a mold portion of the glass press forming apparatus of the present invention, showing a state immediately before press forming.

FIG. 3 is an enlarged sectional view of a mold portion of the press forming apparatus for glass of the present invention, showing a state during press forming.

FIG. 4 is an enlarged cross-sectional view of a mold portion of the glass press forming apparatus of the present invention, showing a state where a molded product is extruded from a lower mold unit after press forming is completed.

FIG. 5 shows an example of the press molding apparatus for glass of the present invention.
4 is a program chart showing an example of molding conditions when manufacturing an optical lens.

[Explanation of symbols]

1 ... frame, 2 ... fixed shaft (upper shaft), 3 ...
Insulated cylinder, 4 ... Upper mold unit (upper mold), 5 ... Die plate, 6 ... Upper mold core, 7 ... Cavity die, 7a ... Opening, 7c ... Guide pin , 8 ...
-Driving device, 9: moving shaft (lower shaft), 10: heat insulating cylinder, 11: lower unit (lower), 12: die plate, 13: lower core (core) ), 14 ... cavity die, 14a ... first opening, 14b ...
2nd opening, 14c: guide hole, 15: slide plate, 17: protruding rod, 18: air cylinder, 21: transparent quartz tube, 22: molding chamber, 2
3 ... Infrared lamp unit, 31 ... Intermediate plate, 32 ... Upper plate, 33 ... Lower plate, 36 ... Control device, 37 ... Load cell, 38
... thermocouple, 50 ... molding material, 51 ... molded product.

Claims (4)

[Claims] 1. A glass molding material is disposed between an upper mold supported from the back side by an upper shaft and a lower mold supported from a back side by a lower shaft, and the upper mold, the lower mold and the molding material are heated. Then, in the glass press forming apparatus that performs press forming by driving the upper shaft or the lower shaft, the lower mold includes a core having a forming surface formed on the front surface, and a core surrounding the outer periphery of the core and guiding the core from the outer peripheral side. And a die plate that supports the core and the cavity die from the back side. The die plate has a through hole that penetrates vertically, and a tip portion is formed inside the lower shaft. A protruding rod housed in the through hole and vertically drivable is incorporated, and by using the protruding rod to push up the core, a product after press molding is extruded from the cavity die. And a press forming apparatus for glass. 2. A glass molding material is arranged between an upper mold supported on the upper shaft from the rear side and a lower mold supported on the lower shaft from the rear side, and the upper mold, the lower mold and the molding material are heated. Then, in a glass press forming apparatus that performs press forming by driving an upper shaft or a lower shaft, the lower mold includes: a plurality of cores having a forming surface formed on a front surface; and a plurality of first openings on a front surface side. Is formed, one second opening communicating with the first opening is formed on the back side, and a cavity die for guiding each of the cores from the outer peripheral side on the inner peripheral surface of the first opening, the second opening And a die plate that supports the respective cores from the back side, and a die plate that supports the slide plate and the cavity die from the back side. The die plate has a through hole vertically penetrating therethrough. Is formed, of the lower shaft A protruding rod whose tip portion is housed in the through hole and can be driven in the vertical direction is incorporated, and by using the protruding rod, the cores are pushed up through the slide plate 0. A press forming apparatus for glass, wherein a later product is extruded from the cavity die. 3. A glass molding material is arranged between an upper mold supported by the upper shaft from the back side and a lower mold supported by the lower shaft from the back side, and the upper mold, the lower mold and the molding material are heated. Then, in the glass press forming apparatus that performs press forming by driving the upper shaft or the lower shaft, the upper mold includes a core having a forming surface formed on a front surface, and a core surrounding the outer periphery of the core and guiding the core from the outer peripheral side. And a die plate for supporting the core and the cavity die from the back side. The die plate is formed with a through-hole penetrating vertically, and a tip portion is formed inside the upper shaft. A protruding rod housed in the through hole and vertically drivable is incorporated, and the pressed product is pushed out of the cavity die by pressing down the core using the protruding rod. And a press forming apparatus for glass. 4. A glass molding material is disposed between an upper mold supported on the upper shaft from the rear side and a lower mold supported on the lower shaft from the rear side, and the upper mold, the lower mold and the molding material are heated. After that, in a glass press forming apparatus that performs press forming by driving an upper shaft or a lower shaft, the upper die includes a plurality of cores having a forming surface formed on a front surface, and a plurality of first openings on a front surface side. Is formed, one second opening communicating with the first opening is formed on the back side, and a cavity die for guiding each of the cores from the outer peripheral side on the inner peripheral surface of the first opening, the second opening And a die plate that supports the respective cores from the back side, and a die plate that supports the slide plate and the cavity die from the back side. The die plate has a through hole vertically penetrating therethrough. Is formed, and of the upper shaft A protruding rod whose leading end is housed in the through hole and is vertically drivable is incorporated, and the protruding rod is used to push down each of the cores via the slide plate, so that after press forming, A press forming apparatus for glass, wherein a product is extruded from the cavity die.