JPH04240122A - Press forming device for optical glass parts - Google Patents

Abstract

PURPOSE:To press-forming optical glass parts continuously and stably to enhance reliability against faults, (to) maintain high producibility and to reduce installation space of device and cost by sharing a part of components of the device. CONSTITUTION:The glass member 5 is arranged between a couple of molds 40,41 and the above-mentioned molds 40,41 and glass member 5 are heated by IR, and plural devices 2 for press-forming optical glass parts are juxtaposed and sequence practiced by the respective forming device is retarded successively with a certain time unit so that the optical glass parts 5 are produced successively within a certain time unit.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical glass component molding apparatus capable of press-molding highly accurate optical glass components such as lenses and prisms.

0002

[Prior Art] In recent years, high-precision optical glass parts, such as lenses, are used not only in optical instruments such as cameras and microscopes, but also in
It is also used in OA equipment, audio equipment, etc.

For example, pickup lenses for CDs (compact discs), which are audio equipment, compete with plastic lenses, but glass lenses are said to be superior because they are less affected by humidity and temperature. It tends to be used frequently.

[0004] Generally, glass lenses are manufactured using grinding technology. For spherical lenses, etc., advancements in grinding technology and superior production equipment mean that lenses go through many processes, but they can be made at a much lower cost.
And made in large quantities. However, in the case of an aspherical lens, it is particularly difficult to grind, so the current situation is that it is not possible to manufacture a high-precision lens at a low cost.

[0005] Recently, a press molding apparatus as shown in Japanese Patent Application Laid-open No. 63-170225 and Japanese Patent Application Laid-Open No. 63-170228 has been proposed, and it is possible to press-form optical glass parts such as aspherical lenses with this apparatus. is possible and has been put into practical use.

Against this background, glass press lenses are being used for aspherical lenses of large diameter lenses, such as interchangeable zoom lenses for single-lens reflex cameras, and high-precision, large-diameter lenses are becoming more and more popular. If possible, it would be extremely effective industrially. Furthermore, if mass production technology could be established for spherical lenses, it would be advantageous as it would be possible to improve productivity compared to the current polishing process.

However, the above-mentioned press molding apparatus uses high frequency induction heating (RF heating) to heat the mold and the molded object (
This method heats the glass material (workpiece), and although the temperature can be raised in a short time, it takes time to cool down after press molding, and there is a problem that productivity cannot be increased very much.

[0008] Unless the temperature of glass is below the glass transition point, the volume will change significantly, which may cause sink marks to appear on the product.
If it is not pressed under an inert gas atmosphere, it will not be possible to stop the press and take it out at high temperatures due to oxidation problems.

[0009] Looking at this takt time, it differs depending on the size and shape of the lens to be molded, and the yield temperature and glass transition temperature differ depending on the type of glass material, so the pressing conditions also change and it is not uniform, but for example, One press molding process includes moving the autoloader, unloading (sequence No. 1), loading (sequence No. 2), and N2 purge (sequence No. 3). ), temperature increase (sequence No.
4) Press mold closing (sequence No. 5), cooling (sequence No. 6), and mold opening (sequence No. 7)
), the sequence No. Combine 1 and 2...30 seconds sequence No. 3...20 seconds sequence No. 4...40 seconds sequence No. 5...30 seconds sequence No. 6...2 minutes 50 seconds sequence No. If the time is 7...10 seconds, one press molding takes 5 minutes. therefore,
Increasing production volume requires multiple units of the same type of equipment, making profitability an issue.

[0010] Also, for example, JP-A-1-133949, JP-A-62-292629, JP-A-63-
Mass production devices have been proposed in Japanese Patent Laid-Open No. 64929, Japanese Patent Laid-Open No. 139019/1983, and the like.

[0011] Many of these systems have a preparatory chamber and perform preheating, pressing, cooling, and other steps while sequentially moving the glass, which is often a so-called assembly line operation, continuous furnace system, or transfer system.

[0012] If such a system can be operated smoothly, some devices may be highly productive. However, there are problems with the equipment configuration, such as keeping the entire furnace in an inert gas atmosphere such as N2 and a means of transporting molds and workpieces at high temperatures. There is a problem in that it must be stopped for maintenance. Considering transfer machines, it seems possible to work at room temperature and in the atmosphere, but
Continuous molding at high temperatures is actually difficult.

[0013]

[Problems to be Solved by the Invention] As described above, in the case of conventional press molding equipment for optical glass parts, when mass producing optical glass parts, it is necessary to operate multiple machines individually or to perform assembly-line operations. It is designed to be carried out in a specific manner. However, in the former case, even if one machine fails, production can be continued with another machine, so it is highly reliable against failures, but it requires multiple machines of the same type, which is uneconomical and requires a large installation space. There are problems such as. In addition, in the latter case, if a failure occurs somewhere on the line,
The entire line had to be stopped for maintenance, and there was a serious problem in that production could not be carried out during this time.

The present invention has been made based on the above-mentioned circumstances, and has high reliability against failures, enables continuous and stable press molding of optical glass parts, and enables high productivity to be maintained. At the same time, it is possible to share parts of the automatic supply/unloading device for supplying glass materials and taking out products, system controllers, etc., and to save space for installing the equipment.
The object of the present invention is to provide a press molding apparatus for optical glass parts that enables downsizing of space and cost.

[0015]

[Means for Solving the Problems] In order to solve the above problems, the present invention includes a plurality of molding apparatuses for press-molding optical glass parts by placing a glass material between a pair of molds and heating the molds and the glass material with infrared rays. A molding unit arranged side by side, and an automatic machine that can freely travel along the installation direction of each molding device of this molding unit and selectively faces each molding device to supply glass material to each molding device and take out products. supply and extraction means;
and a control means for centrally controlling each of the molding devices so that the molding operation sequence executed by each of the molding devices is sequentially delayed by a certain time unit so that optical glass parts are sequentially obtained by a certain time unit. The structure is as follows.

[0016]

[Operation] According to the above structure, a predetermined production quantity can be ensured by setting the number of molding devices in the molding unit. In other words, it depends on the production volume (how many seconds you want to produce), the size of the object to be molded, the glass material, etc., but for example, if it takes 5 minutes to execute a series of press molding processes as in the example above, Assuming that we want to obtain a product every 30 seconds, we would prepare 10 molding devices and change the sequence of molding operations performed by each molding device at fixed time intervals so that the optical glass parts would be obtained one after another in fixed time units. By controlling each molding device in a sequentially delayed manner, it is possible to obtain a product every 30 seconds.

[0017] Furthermore, even if one molding device in the molding unit breaks down, production can be continued with another molding device, and the entire molding unit will not go down. In this way, reliability against failure is high, optical glass parts can be continuously and stably press-molded, and high productivity can be maintained.

[0018] In addition, all molding devices are equipped with an automatic supply/take-out means that can freely travel along the arrangement direction of the molding devices and selectively faces each molding device to supply glass material to each molding device and take out products. There is no need to provide a separate supply and take-out means, and it is sufficient to provide one according to the capacity and production volume of the supply/take-out means, and commonality can be achieved.

Furthermore, each molding device is provided with a control device for executing its respective sequence, and a sequence controller is provided to control the relationship between each molding device and the automatic supply/take-out device. As a result, it is possible to simplify and downsize the control device provided in each molding device, and the sequence controller can be shared, thereby making it possible to reduce the installation space and cost.

[0020] Note that when conventional RF heating is used as a heat source for heating molds and glass materials, the RF power source requires a large floor space, and heating multiple molding devices at the same time with one power source is a matching problem. Since there is no heating power source, it is possible to share the heating power source, and furthermore, it is easy to achieve uniform heating, the efficiency is high, and it is possible to mold optical glass parts with high precision. Further, in terms of equipment, large-sized high-frequency oscillators, busbars, etc. are not required, which is preferable since miniaturization is possible.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall configuration diagram showing an embodiment of the present invention. In FIG. 1, 1 is a molding unit, and this molding unit 1 includes a plurality of molding apparatuses 2, which will be described later. In other words, in the embodiment, a total of 10 molding apparatuses from a first molding apparatus 2a to a tenth molding apparatus 2j are installed. They are arranged in a straight line.

Furthermore, on the front side of this molding unit 1,
An autoloader guide 3 as a guide means is provided along the arrangement direction of each molding device 2a to 2j.
An autoloader 4 serving as automatic supply/removal means is provided so as to be freely movable using a toadder guide 3 as a guide.

This autoloader 4 is connected to each molding device 2a to
A preform 5 as a glass material is supplied to each molding device 2a to 2j selectively facing the molding device 2j, and a lens 5' as an optical glass component (product) is taken out. Reference numeral 6 designates a first mounting table provided parallel to the autoloader guide 3, on which the preforms 5 are placed. Reference numeral 7 denotes a second mounting table provided parallel to the first mounting table 6, on which the lenses 5' are placed.

Further, on the rear side of the molding unit 1, one lamp power supply 8 is provided as a common power supply means for supplying power to the infrared lamps 50 of each of the molding apparatuses 2a to 2j. The lamp power supply 8 has a built-in switching circuit 9, and the output end of the switching circuit 9 and each of the molding devices 2a to 2j are connected via power cables 10. By switching the switching circuit 9, power is selectively supplied to each of the molding devices 2a to 2j.

Next to the lamp power source 8, a hydraulic unit 10 is provided as a hydraulic pressure generating means, and a hydraulic cylinder is used as a mold driving means for moving the lower mold 41 of each molding device 2a to 2j. Hydraulic pressure is supplied to 36. The hydraulic unit 10 has a built-in hydraulic control circuit 12, and the output end of the hydraulic control circuit 12 and each molding device 2 are connected to each other.
a to 2j are connected via hydraulic piping 13 . By switching the hydraulic control circuit 12, hydraulic pressure is selectively supplied to each of the molding devices 2a to 2j.

Furthermore, the right end of the molding unit 1, that is,
A system controller 15 as a control means is provided next to the tenth molding device 2j. The system controller 15 controls, as a system, the relationship between each control device incorporated in each molding device 2a to 2j, an automatic supply/take-out device, and a heating power source, and controls the molding operations executed in each molding device 2a to 2j. The molding apparatuses 2a to 2j are collectively controlled so that the sequence is sequentially delayed in fixed time units so that optical glass parts are sequentially obtained in fixed time units.

The operating conditions and control conditions of each molding device 2a to 2j may be set by each control device built into each molding device 2a to 2j, or by the system controller 15.
You can go there.

FIG. 2 shows the configuration of the molding apparatus. In the figure, reference numeral 20 denotes a fixed shaft as a first shaft whose upper end is fixed to the ceiling of the frame 21, and the lower end of this fixed shaft 20. A fixed die plate 23 is attached through a heat insulating member 22. The heat insulating member 22 is a hollow shaft member 22 made of a heat insulating material such as ceramics such as Si3N4.
The ring member 22b is made of a transparent heat insulating material that transmits infrared rays, such as transparent quartz glass, and is connected to a fixed die plate 23 by bolts (not shown). The fixed die plate 23 has a fixed die 2
4 and an upper cavity die 25 made of ceramics or the like is attached.

Further, reference numeral 26 denotes a moving axis as a second axis disposed coaxially with the fixed axis 20;
A movable die plate 28 is attached to the upper end of the movable die plate 28 via a heat insulating member 27 consisting of a hollow shaft member 27a and a ring member 27b, as described above.
A lower cavity die 30 made of ceramics or the like is attached to the movable die 29.

A preform 5, which is a glass material (lens material), is placed on the lower cavity die 30, and when the preform 5 reaches a predetermined temperature, a system connected to the moving shaft 26 is moved by a hydraulic cylinder 36 as a die driving means. The mating surfaces of the fixed die 24 and the movable die 29 are brought into close contact with each other, and the cavity 17 is formed by the upper cavity die 25 and the lower cavity die 30.
The preform 5 is pressed so as to be deformed into the shape of the lens 5'.

Furthermore, an upper mold 40 consisting of an assembly of the fixed die plate 23, the fixed die 24, and the upper cavity die 25, the movable die plate 28, and the movable die 2
9 and a lower cavity die 30, the lower die 41 is placed in a molding chamber under an inert gas atmosphere surrounded by a cylindrical chamber 44 whose openings at both ends are closed by a base 42 and a bracket 43. It is within 45.

For example, as the lens 5', the outer diameter is 50 mm.
When molding a convex lens of
A quartz tube made of transparent quartz glass with a diameter of 0 mm and a wall thickness of 4 mm was used.

Further, on the outer periphery of the chamber 44 made of a quartz tube, a plurality of annular infrared lamps 50 serving as heating sources are installed.
and an infrared lamp unit 52 consisting of a reflective mirror 51 made of polished aluminum and plated with gold, which is provided to surround the back side of the infrared lamps 50...
has been placed. Then, by energizing the infrared lamps 50, the infrared rays are transmitted through the chamber 44 and irradiated onto the upper mold 40 and the lower mold 41.

Fixed die 24 and moving die 2 at this time
The material of 9 is, for example, a tungsten alloy, and the moving cavity die 25 and the fixed cavity die 28 are made of SiC.
was used, and optical glass with a maximum yield temperature of about 650° C. was used as the glass material.

The infrared lamp 50 has a voltage of about 1.6 at 200V.
KW, 5 stages 10 that output about 2.8KW at 300V
Using this method, heating was performed while adjusting the output, and pressing was performed at a temperature indicated by the thermocouple 55 of about 640°C. The press force was 800 kgf using the hydraulic cylinder 36, and as a result, a good lens 5' was obtained. In the embodiment, the infrared lamp 50 is curved in a semicircular shape, as shown in FIG. 3, and the two infrared lamps 50, 50 are arranged in a substantially circular shape. In addition, in FIG. 3, 56 is a terminal of the lamp, and 57 is an insulator.

Further, as shown in FIG. 2, a cooling unit 59 is provided outside the infrared lamp unit 52, and has water cooling pipes 58 disposed on the back side of the reflective mirrors 51. 51... is designed to prevent damage due to overheating. This cooling unit 59 is attached as necessary.

The infrared lamp 50 is a halogen lamp using a coiled tungsten filament, and its wavy range is wide, but the infrared lamp generally has a peak wavelength in the wavelength range of 1.2 μm to 1.8 μm. It is. This wavelength corresponds to the chamber 44 made of a transparent quartz tube and the heat insulating ring members 22b and 27b made of transparent quartz.
Transmits more than 90% of

Therefore, in combination with the effects of the reflecting mirrors 51..., the upper mold 40 consisting of the assembly of the fixed die plate 23, the fixed die 24, and the upper cavity die 25, the movable die plate 28, and the movable die 29 , and the lower cavity die 30, not only the circumferential surface but also the upper and lower surfaces of the lower mold 41 are heated, efficiently heating the upper mold 40 and the lower mold 4.
It was found that it was possible to heat 1 and to heat it more uniformly.

Although there are some differences depending on the glass material, optical glass generally transmits most of the infrared rays of 1.2 μm to 1.8 μm, so the preform 5 is essentially heated directly with the infrared lamp 50. It is heated indirectly without doing anything.

On the other hand, in the molding chamber 45, arrows A, B,
N2 gas, which is an inert gas, is introduced as shown by C and exhausted as shown by arrow D, replacing the oxygen concentration in the air to a concentration that does not affect the quality of the glass, and then heating begins. There is. Note that the gas supply pipe and gas exhaust pipe are omitted in the figure.

In each of the molding devices 2a to 2j, when the preform 5, which is a glass material (lens material) placed on the lower cavity die 30, reaches a predetermined temperature, the hydraulic cylinder 36, which is a driving device, is activated. operates to raise the lower die 41 and press mold a lens 5' that matches the shape of the cavity 17.

Further, the infrared lamp unit 52, the cooling unit 59, and the chamber 44 made of a transparent quartz tube are integrally assembled with the bracket 43, and these are integrally moved upward by an air cylinder as a driving device (not shown). The molding chamber 45 can be opened as needed. The autoloader 4 can load the preform 5 into the lower cavity die 30 and take out the pressed lens 5'.

Further, in this embodiment, as shown in FIG. 4, the time required for molding in each of the molding devices 2a to 2j is 5 minutes, that is, the movement of the autoloader and the unloading (seed). N2 purge (sequence No. 1) and load (sequence No. 2) for 30 seconds together.
Kens No. 3) is heated for 20 seconds (sequence No. 4)
) is 40 seconds, press mold closing (sequence No. 5) is 3
0 seconds, cooling (sequence No. 6) for 2 minutes and 50 seconds, and mold opening (sequence No. 7) for 10 seconds, 1
One lens 5' can be obtained every 30 seconds by delaying execution by a fixed time unit so that lenses 5' can be sequentially obtained from zero molding apparatuses 2a to 2j in a fixed time unit.

In FIG. 4, No. 1 and no. 2 is road,
As for the unloading sequence, now the autoloader 4
If one unit corresponds to 10 stations, that is, each molding device 2a to 2j, the total time for unloading and loading, including the movement time of the autoloader 4, would be 50 seconds. For example, since the time unit is 30 seconds, after 30 seconds, move to the next station, perform unloading and loading, and sequentially perform 30 seconds.
If you move every second, after 5 minutes you will be at the first station 2a.
, and repeat this process.

[0045] Sequence No. 3 N2 purge is 20
seconds, which is shorter than the predetermined time unit, but in this case 20
When seconds pass, the N2 substitution ends and the next sequence begins at that station.The actual time that N2 gas is flowing is the sequence number. From the start of N2 purge of 3, sequence No. 6 (N2 purge may be stopped before cooling is completed).

[0046] Sequence No. 4 is a temperature increase, in which the infrared lamp is turned on, and the "on" time is 40 seconds or sequence No. The pressing (mold closing) time may be as long as 5.5 seconds. If the infrared lamp 50 is kept "on" during pressing, the unit time will be 70 seconds, which is longer than the unit time of 30 seconds, which is twice as long as 60 seconds.

Therefore, there is always a state in which the infrared lamps 50 are "on" at three stations. Therefore, in order to energize the infrared lamp 50, the power source 8
There are two methods: using multiple power supplies, such as using three power supplies and switching them over in sequence, using a power supply for each station, and using a large-capacity lamp power supply 8 as in this example. There is a method of sequentially switching using This can be decided based on the price of the power supply and changeover switch, the floor space, etc.

[0048] Sequence No. The mold closing in the press 5 may be performed using a hydraulic cylinder, an air cylinder, or a motor, and the driving device is not limited. - tion, that is, each molding device 2a to 2
j must be equipped with a hydraulic cylinder 36,
There is no need to provide a hydraulic unit 11 such as a hydraulic pump for driving the hydraulic cylinder 36 at each station.
It is sufficient if the hydraulic control circuit 12 can be switched. However, in order to prevent pressure fluctuations at each station, valves and the like are required for pressure adjustment and flow rate adjustment.

[0049] Also, sequence No. The press time of sequence No. 5 is 30 seconds, but the press time of sequence No. 5 is 30 seconds. This is an example of a sequence in which pressing is performed until the mold is opened in step 7.
Since the time is 20 seconds, it is about seven times as long as 30 seconds, and this means that the hydraulic cylinders 36 at 7 of the 10 stations are in mold closing mode. However, in reality, the mold opens during cooling, but the N2 atmosphere in the molding chamber 45 only needs to be maintained, and this is done here for the sake of explanation.

In this example, in order to explain in an easy-to-understand way a method for press-molding optical glass parts by installing a plurality of press-molding apparatuses in parallel to obtain a product in a fixed time unit as a means of efficiently increasing productivity, each Although the details of the sequence executed by the molding apparatus have been explained in a simplified manner, the temperature conditions, press conditions, etc. for precision molding are not limited.

[0051]Although the explanation has been mainly based on hydraulic pressure as the mold driving means, a supplementary explanation will be added here regarding the case where an electric servo motor is used. Compared to hydraulic cylinders, electric servo motors are suitable for precise position control, and can be used at any position, at any speed, and with any torque (pressing force).
It is effective when trying to control the temperature and temperature, and is effective in the glass forming sequence of the present invention in which time and temperature conditions are added. When using an electric servo motor, the motor
A driver is provided corresponding to each molding device, but a driver does not necessarily have to be provided correspondingly to each molding device.

As explained above, the point is to increase productivity by efficiently operating a large number of stations (10 stations of molding apparatuses 2a to 2j in the embodiment).

Now, if we consider operating 10 stations at the same time, the productivity is 10 lenses can be obtained in 5 minutes, which means 1 lens every 30 seconds, which is the same as the method of the present invention. Become. However, each station has 4 autoloaders.
If there are 4 autoloaders
If we tried to respond with this, of course we would not be able to produce one piece every 30 seconds. In addition, the initial cost will also be high if all the systems are operated at the same time. This is because the power supply capacity for the power supply 8 of the infrared lamp 50 is large,
This is because an autoloader and controller are required for each station, which also increases the floor space. The same is true even if the 10 stations are not operated at the same time but are operated separately.

In the above explanation, the number of stations is 10, but it is convenient to have a spare station. The reason for this is that even if one of the stations breaks down, it can be covered by using a spare station without changing the takt time.

[0055] Also, for convenience of explanation, the sequence was set to a suitable length of 20 seconds or 30 seconds, but in reality, 20 seconds could be 18 seconds or 22 seconds, depending on how the software is assembled. It can also be handled as follows. For example, a tact lag may be provided. Other features of the present invention will be described. This means that the number of stations can be increased or decreased depending on the takt time, glass material, size and shape of the product, etc.

[0056] Also, in consideration of floor space, in some cases,
Even if the number of autoloaders 4 is increased, a two-story structure is also possible, and it is also possible to consider several stations as one unit. In the explanation so far, the explanation has been given regarding a single lens 5', but it goes without saying that the present invention can also be applied to multiple lenses, prisms, and other optical parts.

Regarding the sequence, for example, N2
I put in a vacuuming sequence before purging,
It is free to open the mold during cooling or to install a system to inspect the product after molding, and there are no restrictions.

According to the above embodiment, since the autoloader 4, controller 15, etc. are efficiently operated for a plurality of stations, the floor space is small and the initial cost of the device is low. , it becomes a highly productive device and can be applied not only to aspherical lenses but also to spherical lenses for optical components such as cameras, microscopes, and OA equipment, and its effects are great. In addition, by unitizing the system, it can be increased or decreased as a system, and is highly flexible, allowing for industrially effective production.

[0059]

[Effects of the Invention] As explained above, according to the present invention,
It has high reliability against failures, allows continuous and stable press molding of optical glass parts, and maintains high productivity. It is possible to provide a press molding apparatus for optical glass parts that can partially be used in common, reducing the installation space of the apparatus and reducing costs.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram showing the overall configuration of an embodiment of the present invention.

FIG. 2 is a schematic longitudinal sectional side view showing the configuration of a molding device which is a main part of FIG. 1;

FIG. 3 is a schematic cross-sectional plan view of the infrared unit section of FIG. 2;

FIG. 4 is an explanatory diagram showing a molding sequence of the molding device.

[Explanation of symbols]

1... Molding unit, 2 (2a to 2j)... Molding device, 4...
Automatic supply and removal means (autoloader), 5... Glass material (preform), 5'... Optical glass parts (lens), 8... Power supply means (lamp power supply), 11... Hydraulic pressure generation means (hydraulic unit), 15...Control means (system controller), 36
...Mold driving means (hydraulic cylinder), 40...Mold (upper mold), 4
1... Mold (lower mold), 50... Heat source (infrared lamp).

Claims (4)

[Claims] 1. A molding unit comprising a plurality of molding devices arranged side by side to place a glass material between a pair of molds and heat the molds and the glass material to press-form an optical glass component; an automatic supply/take-out means that is movable along the arrangement direction and selectively faces each molding device for supplying glass material to each molding device and taking out products; and a molding operation sequence executed by each of the molding devices. and a control means for controlling each molding device in a manner that sequentially delays each molding device in a fixed time unit so that the optical glass parts are sequentially obtained in a fixed time unit. Press molding equipment. [Claim 2] The molding unit is capable of increasing or decreasing the number of each molding device to suit molding conditions such as the type of glass material, size and shape of the molded product, takt time or temperature increase rate, and press release timing. A press molding apparatus for optical glass parts according to claim 1. 3. The press molding apparatus for optical glass parts according to claim 1, wherein a common power source is used for supplying power to the heat source of each molding device of the molding unit. 4. The press molding apparatus for optical glass parts according to claim 1, wherein a common operating source is used for the mold driving means for moving the molds of each molding device of the molding unit.