JP3134489B2 - Glass forming equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass forming apparatus for forming glass products such as lenses.

[0002]

2. Description of the Related Art In manufacturing precision optical glass such as lenses, a method of molding a glass material by pressing means in a molten or softened state has recently become widespread. That is, as a forming die, a forming die including a body die and a lower die and an upper die guided by the body die is provided, a forming part is formed between the upper and lower dies, and a glass material is formed in the forming part. The glass material in the forming part is softened by setting and heating the entire forming die, and press forming of the glass material is performed by pushing up the lower die or lowering the upper die. Here, in order to soften the glass material, the mold is usually heated to a high temperature state of 500 ° C. or higher. When press molding is performed in an atmosphere in which oxygen is present, the surface of the mold becomes An oxide film forms. In particular, if an oxide film is formed on the upper and lower mold surfaces constituting the molding portion, the removal of the oxide film has a bad effect on the subsequent molding of the glass material. Therefore, in order to prevent the formation of an oxide film, the entire mold is housed in a molding chamber, and the interior of the molding chamber is evacuated to an atmosphere of an inert gas such as a nitrogen gas or the like and the oxygen concentration is as low as possible. It is configured to heat and press form underneath.

[0003]

By the way, the supply of the glass material to the molding section and the removal of the molded product from the molding section after molding are performed in the air, and the lower mold and the upper mold are separated from each other. Since the molded product is taken out and a new glass material is set, it is impossible to prevent the inside of the molded portion where the glass material is placed from being exposed to the atmosphere. Also,
When the lower mold and the upper mold are combined after the glass material is set, the inside of the molded portion is almost in a sealed state. Therefore, even if the inside of the molding chamber in which the mold is disposed is replaced with an atmosphere having no oxygen or an atmosphere having an extremely low oxygen concentration, the inside of the molding section between the most necessary lower mold and the upper mold is efficiently used. The atmosphere cannot be replaced.
For this purpose, there is a configuration in which a vacuum chamber is once suctioned to make the inside a negative pressure state, and then a means for supplying an inert gas such as nitrogen gas into the molding chamber is used. Since the mold is fitted almost tightly to the body mold, the sealing inside the molding part is considerably high, so that even if the inside of the molding chamber is under a negative pressure, the inside of the molding part is Exhausting oxygen-containing gases is quite difficult. In particular, in order to automate this glass forming, the forming chamber becomes large due to the necessity of installing a mechanism such as a robot or the like. In addition, there is a problem that the operation of replacing under an inert gas atmosphere becomes more difficult, and an extremely long time is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to quickly and surely establish a necessary portion in a mold under an inert gas atmosphere. It is an object of the present invention to provide a glass forming apparatus which can be reliably replaced by the above-mentioned atmosphere during molding.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a lower mold unit in which a lower mold is mounted in a lower mold section, and an upper section detachably connected to the lower mold section. It consists of an upper mold unit with an upper molding die installed in the body mold part, sets a glass material in the molding part formed between the upper and lower mold parts, heats it, and applies a pressing force between the upper and lower molds A glass material is press-molded, and the lower mold unit and the upper mold unit are each provided with a gas passage opening to the molding section, and one of the two gas passages has a gas passage. An active gas supply unit is connected so that an inert gas can be supplied to the molding unit, and the other gas flow path is connected to at least a suction mechanism unit so that air in the molding unit can be sucked. The feature is.

[0006]

The upper mold unit is separated from the lower mold unit, a glass material is set on the lower mold, and the atmosphere is replaced after the upper mold unit is connected to the lower mold unit.
This atmosphere replacement operation is performed, for example, by connecting the gas flow path provided in the upper mold unit to the suction mechanism unit, connecting the gas flow path of the lower mold unit to the inert gas supply unit, and molding from one gas flow path. This is performed by supplying an inert gas to the molding unit while vacuuming the inside of the unit. The molding part is a substantially closed space defined by the lower body part and the upper body part, and the lower molding part and the upper part. Even if the inside of the molding part becomes lower in pressure than the outside air by vacuum suction. By hardly sucking air, and by supplying an inert gas into the molded portion, the atmosphere can be quickly and efficiently replaced, and an inert gas atmosphere almost completely free of oxygen is obtained.

[0007] When the replacement of the atmosphere is completed, the supply of the inert gas from the gas flow path connected to the inert gas supply unit is continued, and the connection between the suction mechanism and the gas flow path is shut off. In addition, an inert gas is supplied from this gas passage as needed. As a result, the pressure in the molding section becomes higher than the external pressure, and therefore, even if the molding material is placed in the atmosphere to mold the glass material, the interior of the molding section is reliably maintained in an inert gas atmosphere state, When the mold is heated, there is no possibility that an oxide film is formed on the upper and lower mold surfaces of the upper and lower molds that form the molded portion. Since the molded portion is isolated from the outside air so as to be substantially in a sealed state, the introduction of the inert gas for increasing the pressure may be small.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. First, FIG. 1 shows an entire configuration of a press molding apparatus. In the figure, 1 indicates a lower mold unit, and 11 indicates an upper mold unit. The lower mold unit 1 has a lower body mold part 2 and a lower molding die 3 inserted and fitted inside the lower body mold part 2, and a heater 4 is provided around the lower body mold part 2.
Is installed. Similarly to the lower mold unit 1, the upper mold unit 11 also includes an upper body mold part 12 and an upper mold 13 inserted into the upper body mold part 12, and an outer peripheral part of the upper body mold part 12. Is equipped with a heater 14. An upper part of the lower body part 2 is formed with a reduced diameter male stamp part 2a, and a lower part of the upper body part 12 is formed with a female part 12a. The upper die unit 11 is connected to the lower die unit 1 by fitting the stamper 12a into the intaglio. A tapered wall is formed at the upper end of the male seal part 2a to ensure that the seal is fitted.

The lower mold 3 and the upper mold 13 are provided with mold surfaces 3a and 13a, respectively.
The mold surface 13a of the upper mold 3 extends to a position where the mold surface 13a has entered the lower body mold portion 2. Accordingly, the mold surface 3a of the lower mold 3 and both of the mold surface 13a of the upper mold 13 and the lower body mold portion 1 are provided. A portion between the mold surfaces 3a and 13a is a molding portion 20, and a glass material 21 is set in the molding portion 20. Then, the glass material 21 is heated, and in a state where the upper mold 13 is fixed by the upper mold pressing means 22, the plunger 23 for pushing up is driven by a driving means such as a cylinder.
Is projected from a position below the lower forming die 3 to press-mold the glass material 21. In the figure, reference numeral 24 denotes a lower mold unit 1 which holds the lower mold 3 so as not to deviate from the lower body mold portion 2 and which can be positioned at the lowermost position and the uppermost position of the lower mold 3. A positioning rod is shown, and the positioning rod 24 is inserted into an insertion hole 25 provided to penetrate the peripheral body of the lower mold 3. Accordingly, the lower molding die 3 can be displaced in the vertical direction to a position where the positioning rod 24 contacts the upper end 25a and the lower end 25b of the insertion hole 25.

[0010] The entire process from setting the glass material 21 to the forming section 20 to taking out the formed product after processing is completed can be automated. That is, first, the mold is placed on the loader / unloader section, the upper body section 12 is lifted by a handling mechanism such as a robot, the upper mold unit 11 is separated from the lower mold unit 1, and the pick and place means is used. The glass material 21 is arranged on the mold surface 3 a of the lower mold 3. Then, the upper mold unit 11 is moved down, and the lower mold unit 1 is engaged with the inro cage. In this state, the process is shifted to the forming section where the upper die pressing means 22 and the plunger 23 are disposed, and during this time, the glass material 2 is moved.
Heat 1 to soften it. Therefore, the plunger 23 is pushed up in a state where the upper die pressing means 22 is in contact with the upper die unit 11 to press-mold the glass material 21. After the molding is completed, the plunger 23 is pulled down, the upper die pressing means 22 is raised, and then the molding die is moved to the loader / unloader section, and the upper die unit 11 is separated from the lower die unit 1 to form a molded product. Is taken out, and then a new glass material 21 is set.

When the glass material 21 is press-formed, it is necessary to heat the entire molding die by the heaters 4 and 14 to raise the temperature of the glass material 21 to about 500.degree. If this heating is performed in a gas containing oxygen, an oxide film may be formed on the surfaces of the upper and lower molds 3 and 13 and the like. In particular, if an oxide film is formed on the mold surfaces 3a, 13a, unless the mold surfaces 3a, 13a are cleaned, the subsequent molding of the glass material 21 will be adversely affected. In order to prevent such a situation, the atmosphere must be replaced with an inert gas atmosphere. However, as described above, in order to automate the entire molding process, the molding die is reciprocated between the loader / unloader section and the molding section, and the upper die unit is provided in the loader / unloader section. Because of the handling mechanism 11 and the pick-and-place means for setting the glass material 21 and taking out the molded product, a chamber is provided, and when a molding die is arranged in this chamber, the chamber becomes It is quite large and it is extremely difficult to replace the atmosphere in the entire chamber. Therefore, in the present invention, the space in which the mold is arranged is opened to the atmosphere, and only the inside of the molding section 20 in which the glass material 21 is set is replaced with the atmosphere.

For this purpose, gas channels 5 and 15 are provided in the lower unit 1 and the upper unit 11, respectively. The gas flow path 5 in the lower mold unit 1 has a passage 5 a provided in the lower body mold portion 2, and the passage 5 a opens to an insertion hole 25 provided in the lower mold 3. Further, a groove 5b is provided in the outer peripheral portion of the lower molding die 3 at a position between the forming position of the insertion hole 25 and the mold surface 3a, and the groove 5b and the inner peripheral surface of the lower trunk mold portion 2 are formed. A gas passage is formed therebetween. The gas channel 15 on the upper mold unit 11 side is
2 has a passage 15a, which opens into an annular groove 15b formed in the peripheral body of the upper mold 13. Then, a groove 15c is formed on the outer peripheral surface of the upper mold 13 between the forming portion of the annular groove 15b and the mold surface 13a.
Is provided to form a gas passage between the groove 15c and the inner peripheral surface of the upper body mold portion 13.

The passages 5a, 15 in the gas passages 5, 15
Pipes 30 and 31 are connected to a, respectively, and nitrogen gas as an inert gas can be supplied to these pipes 30 and 31. Moreover, in order to perform the atmosphere replacement more efficiently and completely, a pipe 30 connected to the gas flow path 5 on the lower mold unit 1 side is connected to a nitrogen gas supply source 32 such as a nitrogen gas cylinder. The piping 31 to the gas flow path 15 on the 11 side can be selectively connected to a nitrogen gas supply source 32 and a negative pressure source 33 such as a suction pump. A flow control valve 34 is provided in the middle of the pipe 30, and the pipe 31 is selectively connected to a nitrogen gas supply source 32 or a negative pressure source 33 via a switching valve 35. Is provided. The flow control valve 34, the switching valve 35, and the flow control valve 36 are electromagnetic valves that operate based on a signal from a control unit 37 including a microcomputer for controlling the operation of the entire press forming apparatus. In addition, the flow control valves 34 and 36 are formed of electromagnetic proportional valves whose opening area can be changed from 0 (that is, a closed state) to a fully open state based on a control signal from the control means 37.

In press-forming the glass material 21 by the press-forming apparatus having the above-described configuration, first, a forming die is disposed on a loader / unloader section, and the upper die unit 11 is separated from the lower die unit 1. In this state, the glass material 21 is set on the mold surface 3a of the lower molding die 3. Then, the upper die unit 11 is fitted to the lower die unit 1 by means of an inlay. In order to prevent air from being confined between the upper mold 13 and the lower mold 3 when performing this inlay fitting, a pipe 31 communicating with the gas flow path 15 is connected to a negative pressure source 33. If the inside is evacuated, it can be fitted smoothly without resistance. As a result, the molded portion 20 formed between the mold surface 3a of the lower mold 3 and the mold surface 13a of the upper mold 13 is substantially in a sealed state.

When the glass material 21 is set, the atmosphere in the molding section 20 is replaced. For this purpose, the pipe 31 is connected to the negative pressure source 33 by the switching valve 35, and the flow control valves 34 and 36 formed by the electromagnetic proportional valves are fully opened. As a result, the nitrogen gas is supplied to the gas flow path 5 on the lower mold unit 1 side, the nitrogen gas is fed into the molding section 20, and the gas containing oxygen in the molding section 20 is sucked from the gas flow path 15. Is done. As a result, the nitrogen gas smoothly flows into the molding section 20, and the atmosphere is completely replaced without any stagnation or the like, and the inside of the molding section 20 is under a nitrogen gas atmosphere. During the replacement of the atmosphere, the connection of the pipe 31 to the negative pressure source 33 and the connection of the pipe 3
If the connection to the nitrogen gas supply source 32 is performed at the same time and the pressures of the two are balanced or the supply pressure of the nitrogen gas is set to be higher, the inside of the molding section 20 becomes a negative pressure. And the atmosphere is replaced more efficiently. However, even if the molded part 20 may be in a pressure state lower than the atmosphere, the molded part 20 is almost in a sealed state, and therefore hardly sucks air from the atmosphere.

Although the molding section 20 is substantially sealed, since there is a slight gap in the joint surface between the lower mold unit 1 and the upper mold unit 11, outside air flows into the molding section 20. It can't be said that there is no danger of infiltration. Therefore, after the replacement of the atmosphere in the molding section 20 is completed, the switching valve 35 is switched to cut off the communication between the gas flow path 15 and the negative pressure source 33 and connect to the nitrogen gas supply source 32. Further, the flow control valves 34 and 36 are throttled to supply a minute amount of nitrogen gas to the gas flow paths 5 and 15. Thereby, the forming part 21
The inside is always maintained at a higher pressure than the outside air, and the invasion of outside air can be reliably prevented.

As described above, while maintaining the state in which the nitrogen gas is supplied to the forming section 20, the forming die is transferred from the loader / unloader section to the forming section in which the plunger 23 and the upper die pressing means 22 are provided. During this time, or after the mold is stopped at a position in the middle of the transition, and after the mold is moved to the molding section, the heaters 4 and 14 are actuated to heat the entire mold, and the inside of the molding section 20 is heated. Is softened. When the glass material 21 is softened to a state in which press molding is possible, the upper mold pressing means 21 is brought into contact with the upper mold unit 11 and the plunger 23 is pressed.
The lower mold 3 in the lower mold unit 1 is pushed up to form the glass material 21.

When the forming process is completed, the plunger 23 is lowered and the upper die pressing means 22 is moved to the upper die unit 1.
1 and the operation of the heaters 4 and 14 is stopped. Then, the molding die is conveyed to the loader / unloader section, and when the molded product is cooled to a certain extent, the upper mold unit 11 is separated from the lower mold unit 1 and the push-up member provided in the loader / unloader section The lower mold 3 is pushed up to a predetermined height position (not shown), a molded product located on the lower mold 3 is taken out, and a glass material to be newly molded is set.

Here, when the upper mold unit 11 is separated from the lower mold unit 1, it is necessary to prevent the molded product from adhering to the mold surface 13a of the upper mold 13 in the upper mold unit 11. For this purpose, the upper unit 11
Is rapidly cooled, and the mold release is promoted by utilizing the difference in the coefficient of thermal expansion between the upper mold 13 and the molded product in the upper mold unit 11. That is, the flow rate of the flow control valve 36 provided in the pipe 31 is increased to supply a large amount of nitrogen gas to the upper mold unit 11 through the gas flow path 15, and the flow control valve 34 of the pipe 30 is By closing the valve, the supply of the nitrogen gas to the gas flow path 5 is stopped. Since the temperature of the nitrogen gas is lower than that of the heated mold, the upper mold unit 11 is rapidly cooled by air, and the release of the molded product from the upper mold 13 is accelerated.

As described above, the nitrogen gas is supplied to the gas flow path 5 at a large flow rate and a small flow rate.
The nitrogen gas is supplied at a large flow rate and a small flow rate. A timing chart showing the operation timing of these and other members is as shown in FIG.

Thus, at the stage before the heating of the molding die, the inside of the molding part 20 is almost completely replaced with a nitrogen gas atmosphere,
Moreover, since the glass material 21 can be reliably maintained in a nitrogen gas atmosphere until the molding is completed, the press forming is performed in a state where the glass material 21 is heated and softened. In addition, there is no possibility that an oxide film is formed on the mold surfaces 3a and 13a of the upper and lower molds 3 and 13.
Further, since the upper mold 13 is air-cooled by the nitrogen gas introduced into the molding section 20, the release of the molded product from the upper mold 13 can be promoted. When separated from the mold, the molded product can be reliably left on the lower mold unit 1 side.

In the above-described embodiment, the gas flow path 15 can be switched between the negative pressure source 33 and the nitrogen gas supply source 32, but the gas flow path 5 can be connected to the negative pressure source 33 and the nitrogen gas supply source. It is also possible to adopt a configuration that can be switched between the source 32. In addition, although the configuration in which the nitrogen gas is supplied from both gas flow paths 5 and 15 into the molding section 20 after the atmosphere replacement is completed, any one of these gas flow paths 5 and 15 is shown. The nitrogen gas may be supplied only from one of the gas flow paths. Therefore, for example, the gas passages 5 and 1
5 is connected to a nitrogen gas supply source 32 to supply nitrogen gas at a large flow rate and a small flow rate to this gas flow path, and to communicate with and shut off the other gas flow path to the negative pressure source 33. It is also possible to configure. Further, after the molding process is completed, the gas flow path 1 is cooled in order to air-cool the upper mold unit 11.
Although a large amount of nitrogen gas is supplied to the upper mold unit 5, for example, if the mold surface 13a of the upper mold 13 can be smoothly released from the molded product, the upper mold unit 1 is not necessarily used.
There is no need to cool 1. Furthermore, although nitrogen gas is used as the inert gas, other inert gases may be used. Further, the press molding is completely automated, but the setting of the glass material 21 and the removal of the molded product may be performed manually.

[0023]

As described above, according to the present invention, the lower mold unit and the upper mold unit each have a gas passage opening to the molding section, and one of these gas passages has a gas passage. An inert gas supply unit is connected to supply an inert gas to the molding unit, the other gas flow path is connected to a suction mechanism unit, the atmosphere in the molding unit is replaced, and after the atmosphere is replaced, the suction mechanism is replaced. By shutting off the connection between the part and the gas flow path, the molded part under the inert gas atmosphere can be maintained at a higher pressure than the outside air, and the suction of the outside air can be prevented, so that the glass material is heated and softened. In this case, it is possible to reliably prevent the formation of an oxide film on the mold surface or the like constituting the molding portion by heating the molding die.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a press forming apparatus showing one embodiment of the present invention.

FIG. 2 is a timing chart showing timings of supplying and discharging gas during processing together with timing charts of other members.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower die unit 2 Lower trunk | drum 3 Lower molding die 5 Gas flow path 5a Passage 5b groove 11 Upper die unit 12 Upper trunk | drum 13 Upper molding die 15 Gas flow path 15a Passage 15b Annular groove 15c Groove 20 Molding part 21 Glass material 30, 31 Piping 32 Nitrogen gas supply source 33 Negative pressure source 34, 36 Flow control valve 35 Switching valve

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C03B 11/00 C03B 11/12 C03B 40/04

Claims (2)

(57) [Claims] 1. A lower mold unit in which a lower mold is mounted in a lower body, and an upper unit in which an upper mold is mounted in an upper body removably connected to the lower body. A glass material is set in a molding portion formed between the upper and lower mold portions and heated, and a pressing force is applied between the upper and lower mold portions to press-mold the glass material. Each of the mold units is formed with a gas flow path that opens to the molding section, and an inert gas supply section is connected to one of the gas flow paths to supply an inert gas to the molding section. A glass forming apparatus characterized in that it is not possible, and that the other gas flow path is connected to at least a suction mechanism so that air in the forming section can be sucked. 2. The other gas flow path has a structure that can be selectively connected to the suction mechanism section and the inert gas supply section. When the atmosphere is replaced, an inert gas flow is provided in the one gas flow path. Supply, suction from the other gas flow path, after completion of the atmosphere replacement, supply an inert gas to both gas flow paths, to maintain the pressure in the molding portion higher than the external pressure The glass forming apparatus according to claim 1, wherein: