JPH05139759A - Glass supplying method and device - Google Patents

Abstract

PURPOSE:To supply the softened glass lumps which are suitable for production of many kinds of glass molded optical parts in small quantities and obviates the evaporation of glass components and the intrusion of bubbles at the time of cutting. CONSTITUTION:Four pieces of heat resistant shafts 4 are mounted at equal intervals concentrically to a freely turnably provided rotary plate 1 and glass round rods 6 are respectively mounted to the bottom ends of the heat resistant shafts 4. One unit of kanthal heater 5 is provided to face the glass round rods 6 below the glass round rods 6. The glass round rod 6 is inserted into the kanthal heater 5 from above this heater where the glass round rod 6 is heated. The front end of the glass round rod 6 is projected from the lower part of the kanthal heat 5. The glass round rod 6 is heated to 10<2> to 10<6.5> poise viscosity at which the evaporation of the glass component and the intrusion of the bubbles do not arise. The objecting front end is successively cut by a pair of shears 7 provided right under the kanthal heater 5, by which the softened glass lump is obtd. The other glass round rod 6 is thereafter indexed onto the heater 5 and the softened glass lump is obtd. in the same manner as mentioned above.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass feeding method and apparatus for obtaining a predetermined amount of softened glass lumps to be fed to a molding die.

[0002]

2. Description of the Related Art Recently, a method for producing a glass-molded optical component having high shape accuracy and surface quality by simply heating and press-molding a glass material without the need for grinding and polishing has been established. As such a manufacturing method, a manufacturing method applying a direct press method which has already been put into practical use is considered. According to the direct press method, the molten glass heated and melted in the crucible is caused to flow down from the orifice,
This molten glass is cut with a cutting member such as a shear at a predetermined timing, a predetermined molten glass gob is supplied to a molding die, and then press molding is performed. Therefore, the processing steps are significantly shortened as compared with the grinding / polishing method, and the processing cost of the optical component can be significantly reduced.

However, in the above direct press system,
Since a glass material is put into a crucible and the whole is heated and melted at one time, it is not suitable for small lot production of 100 kg or less per lot. In addition, when the type of glass to be melted is changed, crucible replacement / cleaning work is required each time, which causes an increase in setup time and a significant reduction in production efficiency. Further, since the molten glass is stored in the crucible, volatilization of glass components and mixing of impurities are likely to occur during the storage, resulting in deterioration of the quality of the glass optical molded part. Therefore, in order to solve the problems of the conventional direct press system, the following inventions have been disclosed. For example, in the invention described in JP-A-62-292631, a method is disclosed in which a glass round bar is heated and the side surfaces of the heated glass round bar are continuously pressed by a pair of molding dies opposed to each other. .. Further, in the invention described in Japanese Patent Laid-Open No. 63-210036, a glass round bar is heated by a first heater, temporarily stored in a funnel-shaped container, and further discharged at a predetermined viscosity, temperature and flow rate. Then, a method of heating and melting with a second heater is disclosed.

[0004]

However, Japanese Patent Laid-Open No. 62-
In the invention described in Japanese Patent No. 292631, since a glass round bar that is softened by heating but not completely melted is press-molded, there is a problem that the final molded optical element becomes nonuniform. Further, since the side surface of the round glass rod is press-molded at a predetermined interval, the glass surplus portion becomes large, resulting in poor yield and extremely uneconomical. Further, the surplus glass portion needs to be removed by post-processing, which causes a problem of increased processing cost. On the other hand, JP-A-63-21003
In the invention described in Japanese Patent Publication No. 6, although there is an effect that the amount of glass material to be melted once can be reduced as compared with the conventional direct pressing method, finally, the molten glass is supplied by the glass flow. This is the same as the conventional direct press method. Therefore, the glass material is 10 to 10
Since it is necessary to heat the glass to a viscosity of ² poises, there is a problem that as the glass viscosity decreases, volatilization of the molten glass component, entrainment of bubbles, variation in the flow rate, and the like occur. Furthermore, a funnel-shaped container corresponding to the crucible in the conventional direct press system is required, and when the type of glass to be melted is changed, setup work such as container replacement is required as in the conventional case.

The present invention has been made in view of the above-mentioned conventional problems, and various kinds of glass materials can be used, and the present invention can also be applied to the small-lot production of various types of glass-molded optical parts in which the production amount of one lot is small. Another object of the present invention is to provide a glass supply method and apparatus capable of obtaining a high-quality softened glass gob that can secure various qualities such as optical characteristics, appearance quality, and dimensional accuracy of a glass-molded optical component.

[0006]

In order to achieve the above object, the glass feeding method of the present invention is such that at least one glass rod is attached to a mounting portion, and the glass rod is inserted into a heating means to insert the glass rod into the glass rod. The sample was sequentially heated and softened to a viscosity of 10 ² to 10 ^6.5 poise from the tip of the glass rod, and then the tip of the glass rod was cut into a predetermined amount of softened glass block. Further, the glass supply device of the present invention has a mounting portion for mounting at least one glass rod and a heating means for heating the glass rod mounted on the mounting portion to a viscosity of 10 ² to 10 ^6.5 poise from the tip portion. Then, the heating and softening tip portion is cut into a predetermined amount, and the glass rod is composed of a feeding means which is inserted into the heating means and the cutting means at a predetermined speed according to the type and shape of the glass.

[0007]

According to the above glass supplying method and apparatus, at least one glass rod having a required size or glass type is attached to the attaching portion, and the glass rod to be formed is indexed above the heating means. Then, the indexed glass rod is heated and softened while being inserted into the heating means from the tip at a predetermined speed. At this time, the heating means has a glass rod viscosity of 10 ² to 1
It is heated to a temperature equivalent to 0 ^6.5 poise. Then, the tip of the glass rod heated to a predetermined viscosity is discharged from the heating means at the above speed and cut into a predetermined amount of softened glass gob by the cutting means. As a result, the glass material is not melted and held in the crucible or other storage member, and the glass material is directly heated and softened to cut only the necessary portion and amount, so that the production efficiency is improved and the glass component is improved. Is less likely to occur. Furthermore, 1 by heating means
Since heating is performed with a relatively high viscosity of 0 ² to 10 ^6.5 poise, bubbles are not mixed. When heating the glass rod to a viscosity lower than 10 ² poise,
Since the glass rod becomes self-fluid, it becomes difficult to control the cutting amount by feeding the glass rod, and air bubbles are apt to be involved during cutting. On the other hand, when only heating with a viscosity higher than 10 ^6.5 poise is performed, the glass viscosity becomes insufficient and cutting becomes difficult.

[0008]

[Embodiment 1] FIGS. 1 and 2 show a main part of a glass material supplying apparatus according to Embodiment 1 of the present invention. FIG.
FIG. 2 is a plan view. In the glass material supplying device of this embodiment, a disc-shaped rotating plate 1 is attached and arranged at a lower end portion (tip portion) of a shaft 2 connected to a drive device (not shown). The rotary plate 1 is fixed to the shaft 2 at the center of its upper surface, and is provided so as to be vertically movable and rotatable about the shaft 2 by the drive device.

The rotary plate 1 is provided with four through holes 3 on the same circle centered on the shaft 2 at equal intervals. A heat resistant shaft 4 made of alumina is inserted into and fixed to each through hole 3 in parallel with the shaft 2 and on the lower surface of the rotary plate 1, and the protruding length is a canter heater 5 arranged below the rotary plate 1.
It is adjusted to be longer than the length of. Inside the lower end (tip) of the heat-resistant shaft 4, a hollow portion is formed for inserting and holding the glass round bar 6 in the axial direction of the heat-resistant shaft 4, and each heat-resistant shaft 4 holds a glass round bar 6 having a different diameter, glass type, etc. Has been done.

Below the glass rod 6 is a substantially inner diameter 60.
mm, an outer diameter of 100 mm, and a heater length of 100 mm, one cylindrical cantal heater 5 is provided, and the canal heater 5 has a glass rod 6 inserted from the lower end of the glass rod 6 into its inner diameter (opening). The glass rod 6 is arranged so as to face the lower end surface of the glass rod 6. Immediately below the lower opening of the canthal heater 5, a pair of shears 7 for cutting the heat-softened glass round bar 6 is arranged, and the pair of shears 7 can be moved back and forth (moving toward and away from each other) by a driving device (not shown). It is provided.

Next, an embodiment of the glass supply method of the present invention using the above apparatus will be described. First, a glass round bar 6 corresponding to a required glass molded product is set on each heat resistant shaft 4. Next, the driving device is driven to rotate the rotary plate 1 by the shaft 2, and the desired glass round bar 6 is indexed above the canthal heater 5 as shown in FIG. At this time, the Kanthal heater 5
Heats the indexed glass round bar 6 to a temperature corresponding to the viscosity of the glass round bar 6 of 10 ⁵ poise. Subsequently, the rotary plate 1 is lowered through the shaft 2 at a speed of 10 mm / min, and the glass round bar 6 is inserted from the tip into the inner diameter portion of the canthal heater 5. The heating time of the glass round bar 6 is determined by the heater length and the descending speed, but in this embodiment, the glass round bar 6 comes out from the lower end opening of the canthal heater 5 after heating for 10 minutes (see FIG. 3). At this time, the tip of the glass round bar 6 coming out of the Kanthal heater 5 has a molding die (not shown).
It has been softened by heating to a viscosity of about 10 ⁵ poise, which allows press molding. Then, the shear 7 is operated at a timing determined by the initial length of the glass round bar 6, the descending speed and the desired weight of the glass gob to cut the tip of the glass round bar 6 to obtain a desired softened glass gob 8. (See Figure 4).
Then, the glass round bar 6 is further lowered to sequentially obtain the necessary softened glass gobs 8.

When the softening and cutting of one round glass rod 6 is completed, the lowering of the rotary plate 1 is stopped, and then the rotary plate 1 is raised to the initial position as shown in FIG. This initial position is set such that the lower end of the other round glass rod 6 set on the heat resistant shaft 4 is above the upper end of the canthal heater 5. Then, the rotary plate 1 is rotated to index the next glass round bar 6 above the canthal heater 5 (see FIG. 6). At this time, when the glass round bar 6 that has been indexed has a glass type different from that of the above-mentioned softened glass round bar 6, the setting temperature of the cantal heater 5 is equivalent to the viscosity 10 ⁵ poise of the glass round bar 6 that is softened by heating. Switch to the temperature you want. And
When the temperature inside the canthal heater 5 is stabilized at the set temperature, the rotating plate 1 is lowered to insert the glass round bar 6 into the canthal heater 5, and the glass round bar 6 is heated and softened as described above.
The softened glass gob 8 is obtained by cutting.

According to this embodiment, four necessary various glass round bars 6 can be set at the same time, and a predetermined amount of softened glass lumps 8 which have been sequentially softened by heating can be obtained according to the glass molded product to be pressed. Since the glass round bar 6 can be directly heated and softened to the required amount by the cartan heater 5 and cut, the production efficiency is improved and the volatilization of the glass component can be prevented.

[0014]

[Embodiment 2] FIG. 7 is a front view of a glass supply apparatus according to Embodiment 2 of the present invention, FIG. 8 is a plan view of the same, and FIG. 9 is a sectional view of an essential part. In the glass supply apparatus of this embodiment, four round bar descending units 10 are installed on the upper surface of the rotary plate 1 at equal intervals.
A heat-resistant rod 3 for setting a glass rod 6 is inserted and fixed in each round rod unit 10 in a state parallel to the shaft 2 and close to the outer peripheral surface of the rotary plate 1. Below the glass round bar 6 set on the heat-resistant rod 3, at a position facing the glass round bar 6, approximately inner diameter 60 mm, outer diameter 100 mm, heater length 100 m.
A cylindrical cantal heater 5 of m is disposed, and a pair of shears 7 is installed immediately below the cantal heater 5.

As shown in FIG. 9, the round bar lowering unit 10 is provided with an upper base 11 and a lower base 12, and two guide shafts 13 are arranged in parallel between the upper base 11 and the lower base 12. It is fixed. A DC motor 14 is fixedly mounted on the upper surface of the upper base 11, and the DC motor 14 is connected to a DC power supply 16 via a controller 15. DC
A motor shaft 17 of the motor 14 projects from the lower surface of the upper base 11, and a lead screw 18 is connected to the tip of the motor shaft 17 by a connecting pipe 19. The lower end of the lead screw 18 has a bearing 20 fixed to the lower base 12.
It is rotatably held by.

On the other hand, a guide base 21 is provided between the upper and lower bases 11 and 12 with the lead screw 18 and the two guide shafts 13 inserted therethrough. A screw guide 22 and two bushes 23 are inserted and fixed to the guide base 21, the screw guide 22 meshes with the lead screw 18, and the bush 23 is slidably fitted with the guide shaft 13. A chuck portion 24 is provided on the side surface of the guide base 21, and the chuck portion 24 holds the heat resistant shaft 3.

Next, a glass supply method using the apparatus of this embodiment will be described. First, similarly to the first embodiment, the glass round rods 6 are set on the respective heat resistant shafts 3, and the desired glass round rods 6 are indexed on the canthal heater 5. Next, the DC motor 14 is operated to rotate the lead screw 18, and the guide base 21 is lowered to insert the glass round bar 6 into the canthal heater 5. At this time, the descending speed of the glass round bar 6,
That is, the time for heating and softening the glass round bar 6 in the canthal heater 5 is set by controlling the rotation speed of the DC motor 14 by the controller 15. Then, after obtaining a glass lump that has been softened by heating in the same manner as in Example 1, the DC motor 14 is rotated in the reverse direction to raise the heat resistant shaft 3 together with the guide base 21, and the rotating plate 1 is rotated to rotate the necessary glass round bar. Index 6 onto the Kanthal heater 5. Then, the softened glass gob of the glass round bar 6 is obtained in the same manner as above. When one round bar lowering unit 10 is used, the other round bar lowering unit 10 holds the guide base 21 stopped at the uppermost end.

According to the present embodiment, in addition to the effect of the first embodiment, only the round bar descending unit 10 in which the glass round bar 6 to be softened by heating is set is independently operated, and only the necessary glass round bar 6 is operated. Can move up and down, so that a more compact device can be obtained.

FIG. 10 is a front view showing a main part of a glass supply device according to a third embodiment of the present invention. Two glass heaters 5a and 5b are arranged in the glass supply device of this embodiment. The two Kanthal heaters 5a and 5b are the connecting members 25.
A heater exchange shaft 26 that is rotatable is connected to the lower surface of the center of the connecting member 25. That is, the two Kanthal heaters 5a and 5b are provided at symmetrical positions with respect to the heater replacement shaft 26, and the rotation of the heater replacement shaft 26 sets the two Kanthal heaters 5a and 5b on the heat-resistant shaft 3. The glass rods 6 are arranged at positions facing each other. Other configurations are the same as those in the first embodiment. Further, it can be applied to the apparatus of the second embodiment.

In this embodiment, the Kanthal heater 5a is used.
While heating and softening the glass round bar 6 at, the other Kanthal heater 5b is heated to the temperature corresponding to the glass round bar 6 to be softened next. After the desired softened glass block is obtained by heating and softening the round glass rod 6 with the canthal heater 5a, the rotation of the rotary plate 1 causes the next round glass rod 6 to be indexed, and the heater replacement shaft 26 also rotates to reach a predetermined temperature. Indexing of the other heated Kanthal heater 5b is performed at the same time. Then, the heat-softening of the indexed glass round bar 6 is performed by the cantal heater 5b to obtain a desired softened glass block.

According to this embodiment, since the two Kanthal heaters 5a and 5b are provided, while one of the Kanthal heaters 5a (5b) heats and softens the glass rod 6, the other Kanthal heater 5a (5b) is used. The heater 5b (5a) can be heated to a temperature corresponding to the glass round bar 6 that is then softened by heating. Therefore, when different kinds of glass materials are continuously softened, the waiting time until the temperature is stabilized due to the temperature change of the cantal heater 5a (5b) can be reduced, so that the production efficiency can be further improved.

[0022]

As described above, according to the glass feeding method and apparatus of the present invention, a glass rod is used as a raw material, and the glass rod is directly heated and softened from the tip end thereof and then cut. This eliminates the need for a storage member and a setup operation such as replacement and cleaning of the storage member, and can enhance the production efficiency of glass-molded optical components, especially for small lots. Further, since a plurality of glass rods can be attached, as a result, various types of glass molding optical parts can be molded with high productivity. Further, since the glass rod is moved by the feeding means instead of moving and feeding the glass material using the glass flow, a softened glass gob is obtained only by heating the glass rod to a relatively high viscosity state necessary for cutting. be able to. Therefore, it is possible to obtain a high-quality softened glass gob without volatilization of glass components, mixing of bubbles, and the like that are likely to occur by melting to a low viscosity.

[Brief description of drawings]

FIG. 1 is a front view of a glass supply device according to a first embodiment of the present invention.

FIG. 2 is a plan view of the glass supply device according to the first embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a state where a round glass rod is cut.

FIG. 4 is an explanatory view showing a glass round bar after being cut.

FIG. 5 is a front view of the glass feeding device after cutting the first round glass rod.

FIG. 6 is a front view of the glass supply device in a state where a second glass round bar is indexed.

FIG. 7 is a front view of a glass supply device according to a second embodiment of the present invention.

FIG. 8 is a plan view of a glass supply device according to a second embodiment of the present invention.

FIG. 9 is a sectional view of a main part of a glass supply device according to a second embodiment of the present invention.

FIG. 10 is a front view of a glass supply device according to a third embodiment of the present invention.

[Explanation of symbols]

 1 rotating plate 2 rotating shaft 4 heat resistant shaft 5 canthal heater 6 glass round bar 7 shear 8 softened glass 10 round bar descending unit

Claims (2)

[Claims] 1. At least one glass rod is attached to a mounting portion, the glass rod is inserted through a heating means to sequentially heat and soften the glass rod from its tip to a viscosity of 10 ² to 10 ^6.5 poise, and then the glass rod. A glass supply method, which comprises cutting the tip of the glass into a predetermined amount of softened glass gob. 2. A heat-softened tip having a mounting portion for mounting at least one glass rod and a heating means for heating the glass rod attached to the mounting portion to a viscosity of 10 ² to 10 ^6.5 poise from the tip portion. A glass supply device comprising: a cutting means for cutting a portion into a predetermined amount; and a feeding means for inserting a glass rod into the heating means and the cutting means at a predetermined speed according to the type and shape of glass.