JPH0761826A - Cooling of mold of molding machine for optics and device therefor - Google Patents

Abstract

PURPOSE:To remarkably improve the responsibility, the reproducibility and the efficiency in control for cooling a mold by bringing a temperature control rod having a high thermal conductivity into plane contact with the mold and taking heat away from the mold. CONSTITUTION:The shape 53 of the bottom part of a hole 25 made in an upper mold 19 for moving a temperature control rod for the upper mold is designed so that the shape 26a of the top part of the control rod 26 may be brought into plane contact with it. In the same manner, the shape 53 of the bottom part of a hole 30 made in an under mold 20 for moving a temperature control rod for the under mold is designed so that the shape 31a of the top part of the temperature control rod 31 capable of freely performing a vertical motion may be brought into plane contact with it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold temperature cooling method for a molding apparatus for manufacturing a glass optical element having high precision by press molding, and the apparatus.

[0002]

2. Description of the Related Art Conventionally, as a method for controlling the temperature of a mold, there is, for example, the invention described in Japanese Patent Application No. 04-034418. The mold temperature control mechanism of the above invention blows cooling air into the inside of at least one of the upper mold and the lower mold from a mold internal blow pipe via a flow control valve, and controls the flow rate of the cooling air depending on the temperature of the mold. By adjusting, the temperature of the mold is controlled.

[0003]

However, in the apparatus described in the above publication, a gas having poor heat conduction is used as a medium for cooling the mold, and the temperature of the cooling air is not controlled. Therefore, when the cooling air is blown onto the mold, the temperature of the cooling air rises, so that there is a problem that cooling efficiency and responsiveness are poor.

Unfortunately, the present invention was developed in view of the above problems in the prior art, and a mold for an optical element molding apparatus capable of changing the cooling time during the molding process with good response and in a short time. An object of the present invention is to provide a temperature cooling method and an apparatus therefor.

[0005]

DISCLOSURE OF THE INVENTION The present invention is an apparatus for molding an optical element by pressing a glass material that has been softened by heating with a mold disposed in a molding chamber. Is a method of cooling a mold by bringing a temperature control member having a low temperature into surface contact. Further, a mold having a hole formed in the molding surface direction from the center of the bottom, a temperature control member having a surface shape in surface contact with the hole and slidably fitted, and the temperature control member. And a drive mechanism for moving the.

[0006]

In the present invention, it is possible to efficiently and instantly remove heat from the mold by bringing the temperature control member, which is lower in temperature than the mold and has better thermal conductivity than gas, into surface contact with the mold. Become.

[0007]

Embodiment 1 FIGS. 1 and 2 show an apparatus used in this embodiment, FIG. 1 is a vertical sectional view, and FIG. 2 is an enlarged sectional view of an essential part.
A heating furnace 2 having a heater 2a and capable of setting a predetermined temperature by a temperature control device (not shown) is provided adjacent to the side of the molding unit 1. A periphery of the molding unit 1 and the heating furnace 2 is sealed by a cover 3, an upper base 4 and a lower base 5 made of quartz glass or stainless steel to form a molding chamber 6.

The upper and lower bases 4, 5 are provided with gas nozzles 7, 7a connected to an atmosphere gas supply device (not shown), and by the nitrogen gas supplied into the molding chamber 6 via the gas nozzles 7, 7a. Oxidation inside the molding chamber 6 is prevented. An upper mold temperature control rod drive mechanism 14 is installed on the upper base 4.

An upper mold part 8 and a lower mold part 9 are arranged in the molding chamber 6. The upper mold part 8 is fixed to the upper base 4, and the lower mold part 9 is fixed to the tip of the press shaft 10. The press shaft 10 is held slidably in the axial direction by a bearing 12 in a housing 11 fixed to the lower base 5, and
It is installed so that it can be moved up and down by a drive cylinder 13 via a lower mold temperature control rod drive mechanism 15.

The carrier 17 on which the optical material 16 and the optical element after press-molding are placed and conveyed is held by a carrier conveying arm 18, and is held in the heating furnace 2 and between the upper mold part 8 and the lower mold part 9. It is configured to be transportable.

The upper die 19 is provided with a control rod moving hole portion 25 from the center of the bottom portion toward the molding surface, and the control rod moving hole portion 2 is formed.
The bottom shape 53 of 5 is the tip shape 2 of the upper mold temperature control rod 26.
It is formed in a shape that makes surface contact with 6a. The upper die 19 is held by a mount 22 by a fixing member 21, and the mount 22 is fixed to the upper base 4 by a fixing screw 24 via a heat insulating material 23.

A control rod moving hole 25 having the same diameter is formed in the upper mold 19, the mount 22, the heat insulating material 23 and the upper base 4, and is connected to an upper mold cylinder 27 through an upper joint 28 inside the control rod moving hole 25. An upper mold temperature control rod 26 is installed so as to be vertically movable. A cooling water circulation hole 29 for circulating cooling water is formed in the upper base 4.

Similarly to the upper mold 19, the lower mold 20 is also provided with a control rod moving hole 30 from the center of the bottom toward the molding surface, and the bottom shape 53 of the control rod moving hole 30 has a lower mold temperature control rod 31. It is formed in a shape that comes into surface contact with the tip end shape 31a. Further, the lower mold 20 is fixed to the press shaft 10 with the fixing screw 24 via the fixing member 21, the mount 22 and the heat insulating material 23, similarly to the upper mold 19. Similar to the upper base 4, the press shaft 10 is formed with a control rod moving hole 30 having the same diameter as the mount 22 and the heat insulating material 23, and is connected to the lower die cylinder 33 via a lower joint 32 inside thereof. A lower mold temperature control rod 31 is installed so as to be vertically movable.

The upper and lower die cylinders 27 and 33 are connected to a pneumatic pressure source 36 via control valves 34 and 35, respectively. The controller 41 controls the control valves 34 and 35. Upper mold 19 and lower mold 20
Are controlled to a constant temperature by an upper mold thermocouple 42, an upper mold temperature controller 39 and an upper heater 37, and a lower mold thermocouple 43, a lower mold temperature controller 40 and a lower heater 38, respectively.

In the mold temperature cooling method using the apparatus having the above structure, first, the nozzle 7 of the lower base 5 is placed in the molding chamber 6.
Nitrogen gas or the like is supplied to reduce the oxygen concentration inside the molding chamber 6. Next, the heating furnace 2, the upper die 19 and the lower die 20 are heated to a predetermined temperature by the heater 2a, the upper die heater 37 and the lower die heater 38.

In this state, the optical material 16 is placed in the carrier 17 and is carried into the heating furnace 2 by the carrier carrying arm 18, and the optical material 16 is heated and softened by the heater 2a until it becomes a moldable state. At this time, the temperatures of the upper die 19 and the lower die 20 are constantly monitored by the thermocouples 42 and 43, and the temperature controllers 39 and 40 adjust the powers of the upper and lower die heaters 37 and 38 based on the information, and are always constant. It is controlled to reach the temperature.

Next, the carrier carrying arm 18 is advanced to carry the optical material 16 together with the carrier 17 between the upper mold 19 and the lower mold 20. Then, the lower mold 20 is raised by the cylinder 13 via the press shaft 10 to perform press molding. Then, at least one of the upper and lower control valves 34
Alternatively, 35 is switched in accordance with a command from the controller 41, and at least one of the upper and lower mold temperature control rod drive cylinders 27 and 33 is always operated at the same timing in each cycle so that the contact surfaces of the upper and lower mold temperature control rods 26 and 31 are changed. The inner contact surfaces of the upper and lower molds 19 and 20 are brought into surface contact.

By this operation, the heat of the central portions of the upper and lower dies 19 and 20 is removed by heat conduction, so that the temperatures of the upper and lower dies 19 and 20 can be cooled in a shorter time and with less variation than the conventional air cooling. Therefore, the time of the cooling process is shortened, the molding cycle can be shortened, and the same molding quality can be always ensured by managing the operation variations of the upper and lower mold temperature control rod drive cylinders 27 and 33.

After the press molding is completed, the lower mold 20 is lowered and released, and the optical element molded by the carrying arm 18 is taken out from the molding chamber. After this, the upper and lower molds 19,
The upper and lower mold temperature control rods 26 and 31 contacting the inside of 20 are returned to their original positions. Then, the temperature control rods 26 for upper and lower molds,
Due to the contact between the outer peripheral surface of 31 and the inner peripheral surfaces of the control rod moving hole portions 25 and 30, heat of the upper and lower mold temperature control rods 26 and 31 is removed, and the upper base 4 or the press shaft 10 is cooled to the same temperature. .

According to this embodiment, since the upper and lower mold temperature control rods are connected to and controlled by the upper and lower mold cylinders, it is possible to easily control the moving timing and moving speed of the upper and lower mold temperature control rods. Cooling control during the molding press can be performed with good reproducibility.

[0021]

[Embodiment 2] FIG. 3 is an enlarged sectional view of an essential part of an apparatus used in this embodiment. In this embodiment, the upper mold temperature control rod drive mechanism 14 and the lower mold temperature control rod drive mechanism 15 in the first embodiment are different, and the other components are the same. The same numbers are assigned and the description thereof is omitted. The upper mold 50 and the lower mold 51 are formed with the control rod moving hole portions 25 and 30 and the bottom shape 53 similar to those in the first embodiment, and are also provided with air vent holes 52, respectively.

The upper mold part 8 includes an upper mold 50, a mount 22,
The control rod moving hole 2 having the same diameter as the heat insulating material 23 and the upper base 4.
5 is formed, and the upper base 4 is provided with a supply / discharge port 44 connected to the control rod moving hole 25. An upper mold temperature control rod 45 is vertically movably fitted inside the control rod moving hole portion 25.

Similar to the upper mold part 8, the lower mold part 9 is also formed with a control rod moving hole part 30, and the press shaft 10 is provided with a supply / discharge port 44 connected to the control rod moving hole part 30. There is. Further, a lower mold temperature control rod 46 is vertically movably fitted inside the control rod moving hole portion 30. Each of the supply / discharge ports 44 is connected to the air pressure source 3 via the control valves 48, 49.
6 and a vacuum source 47. The controller 41 controls the control valves 48 and 49.

The mold temperature cooling method using the apparatus having the above structure is the same as that of the first embodiment up to the pressing step, and the description thereof will be omitted. Subsequent to the pressing step, at least one of the upper and lower control valves 48 or 49 is switched by a command from the controller 41, and the temperature control rods 45 and 46 for the upper and lower dies are raised or lowered so that the contact surfaces thereof are the upper and lower dies 50 and 51. It is assumed that the heat of the central portions of the upper and lower molds 50, 51 is taken away by heat conduction to cool the upper and lower molds 50, 51 by making surface contact with the inner contact surface of the.

After the press molding is completed, the lower mold 20 is lowered and released, and the molded product is taken out from the molding chamber by the transfer arm 18. After that, by switching the control valve 48 or 49 to the vacuum source 47, the temperature control rods 45, 46 are
Is separated from the upper and lower molds 50 and 51. The outer peripheral surfaces of the temperature control rods 45 and 46 come into contact with the inner peripheral surfaces of the control rod moving hole portions 25 and 30 to remove heat, and are cooled as in the first embodiment.

According to the present embodiment, the temperature control rod driving mechanism for the upper and lower molds can be simplified by driving the temperature control rod for the upper and lower molds using positive pressure and negative pressure.

[0027]

[Embodiment 3] FIG. 4 is an enlarged sectional view of an essential part of an apparatus used in this embodiment. In this embodiment, the upper mold temperature control rod drive mechanism 14 and the lower mold temperature control rod drive mechanism 15 in the first embodiment are different, and the other components are the same. The same numbers are assigned and the description thereof is omitted.

In the upper die portion 8, a control rod moving hole portion 25 having the same diameter is formed in the upper die 50 having the air vent hole 52, the mount 22, the heat insulating material 23 and the upper base 4, and the control rod moving hole portion is formed. An upper mold temperature control rod 65 having a cooling water circulating portion 55 is slidably inserted into the space 25. Also,
The cooling water circulation unit 55 has a cooling water supply port 56 and a cooling water drain port 57, and circulates cooling water 58 whose temperature is controlled to a constant temperature by a cooling water circulator (not shown).

The end portion of the upper mold temperature control rod 65 has a guide 6
1, ball screw 62, belt 63 and servo motor 6
It is held by a holding unit 60 which is driven by 4. The servo motor 64 is controlled by the controller 41. The lower mold part 9 also has the same structure as the upper mold part 8 described above, and the same reference numerals are given and the description thereof is omitted.

The mold temperature cooling method using the apparatus having the above-mentioned structure is the same as that of the first embodiment up to the pressing step, and the description thereof will be omitted. Subsequent to the pressing step, at least one of the upper and lower servo motors 64 is rotated by a command from the controller 41, and the holding unit 60 containing the ball screw 62 is moved up and down via the belt 63. By this operation, the temperature control rods 65 and 66 for the upper and lower dies slide in the direction of the die molding surface while making surface contact with the inside of the control rod moving holes 25 and 30.

At this time, the upper and lower mold temperature control rods 65 and 66 move while the insertion speed and the insertion position are controlled by the controller 41 according to the mold temperatures measured by the thermocouples 42 and 43. The cooling speed can be increased by increasing the insertion speed or deepening the insertion position. Further, the temperature-controlled cooling water 58 circulates in the cooling water circulation portion 55 inside the upper and lower mold temperature control rods 65 and 66, and is cooled to a constant temperature.

After the press molding is completed, the lower mold 20 is lowered and released, and the molded product is taken out of the molding chamber by the transfer arm 18. After that, the servo motor 64 is rotated in the reverse direction, and the upper and lower mold temperature control rods 65 and 66 are separated from the mold.

According to this embodiment, the cooling speed and timing can be controlled more accurately than in the above embodiments by digitally controlling the moving speed and position of the upper and lower temperature control rods by the servomotor. it can.

[0034]

As described above, according to the mold temperature cooling method for the optical element molding apparatus and the apparatus therefor according to the present invention, the temperature control rod is lower in temperature than the mold and has better heat conduction than gas. By taking the heat of the mold by bringing the mold into surface contact with the mold, the response, reproducibility and efficiency of mold temperature cooling control can be greatly improved, shortening the molding cycle time and improving the molding quality. Easy to manage.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a first embodiment.

FIG. 2 is an enlarged cross-sectional view of a main part showing the first embodiment.

FIG. 3 is an enlarged sectional view of an essential part showing a second embodiment.

FIG. 4 is an enlarged sectional view of an essential part showing a third embodiment.

[Explanation of symbols]

 1 Molding Part 2 Heating Furnace 6 Molding Room 8 Upper Mold Part 9 Lower Mold Part 10 Press Shaft 11 Housing 13 Driving Cylinder 14 Upper Mold Temperature Control Rod Driving Mechanism 15 Lower Mold Temperature Control Rod Driving Mechanism 16 Optical Material 17 Carrier 18 Carrier transfer arm 19 Upper model 20 Lower model

[Procedure amendment]

[Submission date] May 26, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Title of invention

[Correction method] Change

[Correction content]

Mold temperature cooling method of the optical element forming the form system [Title of the Invention] The apparatus

Claims (2)

[Claims] 1. An apparatus for molding an optical element by pressing a heat-softened glass material with a mold disposed in a molding chamber, wherein at least one mold is provided with a temperature control member having a temperature lower than that of the mold. A mold temperature cooling method for an optical element molding apparatus, which comprises contacting the surfaces to cool the mold. 2. A mold having a hole formed in the molding surface direction from the center of the bottom, a temperature control member having a surface shape in surface contact with the hole and slidably fitted therein, A mold temperature cooling device for an optical element molding device, comprising a drive mechanism for moving a temperature control member.