CN1100071A - Method for producing precision glass article - Google Patents

Abstract

The invention provides a method for producing precision glass products with molten glass, comprising a series of steps: receiving a predetermined amount of molten glass with a receiving mold, which flows out from a glass outlet of a melting furnace; using the receiving mold and the glass received thereon A predetermined amount of molten glass is sent into a replacement chamber; the molten glass is preformed to a predetermined shape in the replacement chamber; the inside of the replacement chamber is evacuated; the replacement chamber is filled with non-oxygen gas; Press a precision glass product of the desired shape in a molding chamber in an atmosphere.

Description

The present invention relates to a method of producing precision glass products, and more particularly to a method of directly molding a high-precision glass product, such as an aspherical lens, from molten glass through a series of molding steps.

In order to produce high-precision glass products such as optical components, there has recently been interest in a method of softening the glass material by reheating and directly pressing the softened glass in a mold; instead of the traditional method of grinding, Polished glass.

In the compression molding method of this kind of precision glass products, the following steps are usually carried out: the soft state glass material is molded with a molded part, the molded part is composed of an upper mold and a lower mold, and the mold is operated in a non-oxygen atmosphere performed so that the shape of the molded surface of the molded article is transferred to the glass material, and then the molded article is cooled in the mold to separate the molded article from the mold at a predetermined temperature or lower.

The glass material used in this method is a glass block, which has the desired shape (glass preshape), has a smooth surface obtained by grinding, heat treatment or chemical treatment, or, this glass block has no surface defects, obtained by melting The glass is obtained and used directly for molding in various forms such as spherical, flat, etc.

However, in the conventional method, the glass material is pre-shaped and then heated and compression-molded, and the pre-forming and compression-molding processes are performed separately. Therefore, even if the glass block has the desired shape, it is obtained by thermal deformation from the molten glass, which flows out from the outlet of the melting furnace, and is directly used as a glass material for the molding process, where not only time and labor are required to be carried out after the pre-shaping Cooling and transport, and cleaning and inspection steps are required to eliminate surface defects caused by foreign substances before molding. Furthermore, reheating in the molding step requires considerable energy to greatly impair production efficiency.

To avoid these drawbacks, continuous production from molten glass to final product is ideal. To this end, Japanese Laid-Open Patent No. 3-45523 proposes a production method for optical elements, in which molten glass flowing from a furnace is received by a first thermal work fixture in a non-oxygen atmosphere, and then a second thermal work fixture Contact the molten glass, then turn it over, and through thermal deformation, a predetermined glass pre-shape is formed on the hot work fixture, and then pressed in the mold.

However, in order to achieve the ideal production described above, there are still some problems to be solved with this method:

(1) The following problems arise when placing a glass melting furnace, especially where the glass outlet is in a non-oxygen atmosphere. Because the glass outlet temperature must be kept low in order to stop the glass flow until the discharge of the glass begins, the glass material present near the outlet cannot be easily vitrified, or, even if it is vitrified, it will contain a lot of air bubbles and Colored streaks due to lack of agitation at this location. Therefore, it is impossible to obtain satisfactory quality of the glass discharged from the outlet. A considerable amount of glass has to be excluded at the beginning. If this exclusion operation is carried out in a narrow space limited by a specific atmosphere, it will be very difficult no matter whether it is automatic or manual.

Moreover, if the glass outlet is to be maintained at a high temperature, the space required for the atmosphere must be sealed, which will make the equipment very complicated. Also, the flow of molten glass from the glass outlet creates a large amount of volatile matter that contaminates the space of the specific atmosphere, and because of this volatile matter, the glass material is eventually contaminated, so that the product cannot maintain high quality.

(2) Receiving molten glass onto a mold in a specific atmosphere involves the following problems: volatile substances that eventually appear in the atmosphere will deposit and contaminate the mold, and it is very difficult to clean the mold in this atmosphere. Furthermore, the molds used to receive the molten glass were heated to a high temperature and were significantly damaged. However, since the mold is in a specific atmosphere, it is not easy to replace the mold with a new one.

The present invention can solve the above problems. The first object of the present invention is to provide a method for producing precision glass products, which can prevent contamination of a specific atmosphere space and maintain high quality of glass products, and, starting from glass melting, in a continuous process Achieve high productivity in glass molding.

A second object of the present invention is to provide a method for producing precision glass products which can simplify a series of steps including forming a glass preform, thereby improving productivity and preventing thermal damage of a mold for pressing.

According to the present invention, the above objects are achieved by the following method: a method of producing precision glass products from molten glass, characterized in that the method comprises the following series of steps including a molding step: receiving a predetermined amount of molten glass with a receiving mold, It flows from a glass outlet of a melting furnace; the receiving mold and a predetermined amount of molten glass received thereon are sent into a displacement chamber; the molten glass is preformed into a predetermined shape in the displacement chamber; the interior of the displacement chamber is evacuated ; Fill the replacement chamber with non-oxygen gas; press the precision glass products of the required shape in a molding chamber that communicates with the replacement chamber and maintains a non-oxygen atmosphere.

According to the present invention, there is also provided a method as follows: a method for producing precision glass products from molten glass, characterized in that the method comprises a series of steps including a molding step: receiving a predetermined amount of molten glass with a receiving mold , flowing out from a glass outlet of a melting furnace; the receiving mold and a predetermined amount of molten glass received thereon are sent to a replacement chamber; the molten glass is preformed into a predetermined shape in the replacement chamber; Before, after or during the steps, non-oxygen gas is filled into the replacement chamber; and, in a molding chamber communicated with the replacement chamber and maintaining a non-oxygen atmosphere, the precise glass product of desired shape is pressed.

According to the present invention, there is also provided a method as follows: a method for producing precision glass products from molten glass, characterized in that the method comprises a series of steps including a molding step: separating a predetermined amount of molten glass, which Flow out from the glass outlet of the melting furnace, and adjust the molten glass to a temperature corresponding to the glass viscosity of 10 ⁴ -10 ¹⁰ dPa.s; the glass is fed into a mold, and the mold is adjusted to correspond to 10 ¹¹ -10 ¹⁴ dPa. s the temperature at which the glass is viscous; and, pressing the glass with a mold.

As mentioned above, the glass flowing out of the glass outlet located in the atmosphere is received by the receiving mold, and then sent to the replacement chamber maintained in a non-oxygen atmosphere, and the non-oxygen atmosphere in the replacement chamber or in the mold chamber communicating with it The bottom is pre-molded or molded. The volatile substances emitted from the glass flowing out of the glass outlet will never be brought into the replacement chamber or the molding chamber; even if these volatile substances are brought in, they will be removed by vacuum and the flow of non-oxygen gas. The specific atmosphere space is free from contamination and maintains high product quality, minimizing cleanup and improving productivity. In particular, since the evacuation is performed under the condition that after the glass is received by the receiving mold, the surface of the glass has been solidified to a certain extent, it is possible to prevent the generation of air bubbles from the inner surface of the glass and to prevent the contamination of the mold by volatile substances, thereby maintaining the replacement chamber and the molding pressure. Cleaning of the interior of the room. In addition, replacement of the receiving mold can be facilitated by utilizing a state in which the receiving mold is inevitably transferred from the replacement chamber to the air in order to receive the molten glass.

The temperature of the glass or mold is controlled to correspond to (10 ⁴ -10 ¹⁰ ) dPa.s or (10 ¹¹ -10 ¹⁴ ) dPa.s respectively, and the required number of glass blocks (glass drops) from the molten glass Received directly by the receiving mold, or by a press mold, pre-molded (preliminary molding) or molded (proper molding) of the glass so that satisfactory molding can be achieved without thermal damage to the mold and without Defects such as glass wrinkles occur on molded articles due to heat shrinkage.

The present invention will be described in detail below in conjunction with the accompanying drawings.

Fig. 1 shows an example of the equipment used in the present invention;

Fig. 2 is a side view showing an example of the precision glass product to be molded according to the present invention;

Fig. 3 is a side view showing another example of the precision glass product to be molded according to the present invention;

4A-4C show some process steps of an embodiment of the present invention;

5A-5C show some process steps of another embodiment of the present invention;

Fig. 6 is a graph showing the temperature control of the molding process in the pre-molding by weight spontaneous deformation in the present invention;

Fig. 7 is a graph showing the temperature control of the molding process in pre-molding with a mold in the present invention;

8A-8E show the steps of an embodiment of the molding process temperature control of the present invention;

Fig. 9 is a cross-sectional view showing a molding of the above-mentioned embodiment;

Fig. 10 is in described embodiment, the mold surface figure that measures with Fizeau interferometer;

Figure 11A-11E shows the steps of another embodiment of temperature control in the mold of the present invention;

Fig. 12 is the sectional view of above-mentioned embodiment molding;

13A-13E show the steps of another embodiment of mold temperature control of the present invention;

Fig. 14 is the sectional view of above-mentioned embodiment molding;

15A and 15B are diagrams of the surface shape of the mold measured by a Fizeau interferometer in the above embodiment.

Next, the first embodiment of the present invention will be described in detail with reference to the accompanying drawings 1-7. 1 shows an example of an apparatus for performing the method of the present invention, wherein a furnace 20 is located outdoors, and glass material is melted, and the molten glass 23 flows down to an outlet 22 through a pipe 21 provided at the bottom of the furnace 20 . Around the furnace 20 and tube 21, a heater (not shown) is provided to melt the glass material and regulate the temperature of the glass exiting the outlet 22.

A replacement (exchange) chamber 10 is provided below the outlet 22, and is connected to a molding chamber 11 through a gate valve 18, and the chamber 11 is connected to a demoulding chamber 12 through a gate valve 19 again. The replacement chamber 10 is provided with a receiving mold 1 that is directly below the outlet 22 when it is stretched out from the chamber 10, and the chamber 10 also includes a chamber body 13; a chamber cover 14 for opening the chamber body (to atmosphere) or a sealed chamber.

An inlet cylinder 32 is provided on the side of the chamber body 13; a drive cylinder 35 is provided at the bottom for raising or lowering the receiving mold 1; and the cylinder shafts 33, 36 of the cylinders 32, 35 are inserted into the replacement chamber through rubber sealing rings 62, 63 10. At the end of the shaft 36 is mounted the receiving mold 1, which is maintained by a heater 51 at a predetermined temperature, for example, such that the viscosity of the glass is in the range of 10 ⁸ -10 ¹² dPa·s.

As shown, the molten glass flowing out from the outlet 22 is held by the receiving mold 1, and a glass gob 24 is formed by thermal deformation of the glass. At this point the cylinder 35 begins to lower the shaft 36 and the mold 1 is brought into the chamber 10 together with the glass gob 24 . The chamber cover 14 is then closed in direction A onto the sealing ring 61 . Therefore, the replacement chamber 10 is maintained in an airtight state, and is evacuated by a suitable suction device. A non-oxygen gas is then fed in order to maintain a non-oxygen atmosphere inside the chamber 10 . Prior to retraction into the chamber 10, most of the volatiles contained in the glass are expelled from the glass block 24 to the air. However, even if brought into the chamber 10, volatiles will still be exhausted out of the chamber 10 by vacuuming.

A glass block 24 having a lens-like convex outer surface shape is preformed into the required shape by supplying non-oxygen gas (nitrogen) to the chamber 10 under the temperature conditions shown in FIG. 6 only by thermal deformation (dead weight deformation), Thereafter, when the oxygen concentration drops to a predetermined level, the gate valve 18 is opened. Then, the glass block 24 entering the chamber 10 is sucked by the suction claw 34 at the end of the shaft 33, and the cylinder 32 is activated to move the block 24 from the chamber 10 into the molding chamber 11.

In addition, if the block 24 having a lens-like convex surface shape cannot be preformed into a desired shape by thermal deformation (dead deformation), mechanical prefabrication is performed as follows. In this embodiment, the chamber cover 14 is provided on the outside with a preformed cylinder 30 whose shaft 31 is bound into the replacement chamber 10 through a rubber seal 69, and a preformed upper mold 2 is combined with a heater 52, be contained in axle 31 ends.

After the cover 14 is closed, the pre-production (pre-molding) of the upper mold 2 is started under the temperature conditions shown in FIG. 7 . Then evacuate and replace the gas. Thereafter in the same manner as above, the gate valve 18 is opened, after which the pre-made glass block 24 is sucked by the suction claws located at the shaft end 33, and the cylinder 32 is activated to move the block 24 into the molding chamber 11 from the replacement chamber 10.

A heater 53 is provided to control the temperature in the chamber 10 to maintain the non-oxygen atmosphere at an appropriate temperature.

The molding chamber 11 is provided with a main molding mold in an airtight chamber body 15, and is airtight from the outside world. The molding chamber body 15 is provided at its upper and lower portions with an upper molding cylinder 37 and a lower molding cylinder 39 for precision molding, and their cylinder shafts 38, 40 are inserted into the chamber 11 through rubber seals. A cover 7 is housed on the bottom of the shaft 38 and is used to open and close the mold 3. A cylindrical mold 5 is arranged between the shafts 38 and 40, and an upper mold 3 and a lower mold 4 are slidably inserted into a vertical mold 5 hole.

When the die is in operation, the upper die 3 can be pressurized by the cylinder 37, through the end of the shaft 38, and the upper die 3 can also be raised with the cover 7, through its upper flange. The lower mold 4 is supported by a bottom plate 6 mounted on the lower part of the mold 5, and is mounted vertically movable therein. Cylindrical mold 5 is also equipped with patrix heater 54, counterdie heater 55, in order to regulate the temperature of patrix 3, counterdie 4.

The glass block that moves in from the chamber 10 through the suction claw 34 is placed on the lower mold 4, and is pressed by the descending upper mold at required temperature and pressure. The temperature and pressure of the mold as well as the glass moldings were controlled as shown in FIGS. 6 and 7 . During this operation, the same non-oxygen atmosphere is maintained in the chamber body 15 of the chamber 11 .

Similar to chamber 10, demoulding chamber 12 comprises a chamber body 16, chamber cover 17, and chamber body 16 is provided with a desktop driving cylinder 41 and demoulding cylinder 44 at its bottom, and their shafts 42, 45 are sealed by rubber. The collars 67 , 68 are inserted into the chamber 12 . Inside the chamber 12, a table 43 for receiving moldings is provided at the end of the shaft 42. Also, the shaft 45 is provided at its end with suction claws 46 for sucking the molded product on the lower mold 4 and placing it on the table 43 by the movement of the shaft 45 of the cylinder 44 .

Between the cover 17 and the hole of the chamber body 16, a rubber sealing ring 66 is provided to obtain an airtight state when the cover 17 is closed. Similar to the chamber body 13, the chamber bodies 15 and 16 are also provided with vacuum suction means (not shown), exhaust holes, and means for supplying atmospheric gas (not shown). Wherein, the glass block 24 is prefabricated only by thermal deformation (dead weight deformation), and the upper mold 2 , the cylinder 30 and the cylinder shaft 31 in the chamber 10 are unnecessary.

example 1:

The method of the present invention will be described in detail with specific examples through data. A process for molding a precision glass product (crescent concave lens), as shown in Fig. 2, which has an effective diameter of 13 mm and an outer diameter of about 17 mm will be described below. For compression molding, the viscosity characteristics of the glass material used are: at 1040°C, the viscosity is 10 Pa.s; at 580°C, the viscosity is 10 ^8.2 Pa.s; at 515°C, the viscosity is 10 ¹¹ Pa.s and at 465°C, the viscosity is 10 ¹⁴ Pa.s.

First, the glass raw material is put into the melting furnace 20 and becomes glass therein, and then stirred to produce a homogeneous glass 23, after which the glass 23 is introduced into the pipe 21, and its temperature is adjusted to a corresponding temperature corresponding to the glass viscosity of 10 Pa.s.

The gate valves 18 and 19 are closed, the compression molding chamber 11 and the demolding chamber 12 are replaced by vacuum, and then nitrogen gas is supplied as a non-oxygen gas. In addition, the heaters 54 and 55 of the cylindrical mold are energized to heat the upper mold 3 and the lower mold 4 to a temperature corresponding to a glass viscosity of 10 ^8.5 Pa.s.

The receiving mold 1 and, if necessary, the prefabricated upper mold 2 are heated by heaters 51, 52 to a temperature corresponding to a glass viscosity of 10 ¹² Pa.s.

Afterwards, chamber cover 14 is opened, and cylinder 35 is started, and the moving mold 1 is directly below outlet 22. Then, as shown in FIG. 4A, the glass is melted and flows out of the outlet 22 and received by the mold 1, and a predetermined amount of molten glass gob is formed on the mold 1 by dead weight deformation, and then the shaft 36 is lowered, the cover 14 is closed, and the mold 1 is closed. Cylinder 30 is started immediately, and the glass block is preformed on mold 1 by upper mold 2 under a pressure of 500N, thereby obtaining glass material 24 (Fig. 4B) of desired shape.

After preforming, when the glass surface reaches a temperature corresponding to a viscosity of ^10⁶ Pa·s or higher, the replacement chamber 10 is evacuated for 10 seconds, and then, non-oxygen gas (nitrogen) is supplied for 5 seconds. Then the gate valve 18 is opened, and the cylinder 32 starts to extend the shaft 33, thereby driving the suction claw 34 to a position above the pre-made glass frit 24a. Axle 36 starts afterwards, and material 24a is sucked by claw 34, and axle 36 shrinks downwards. Cylinder 32 moves further to make shaft 33 move material 24a to molding chamber 11, and place it on lower mold 4 (in this state, the viscosity of glass is 10 ⁹ Pa.s and upper mold 3 and lower mold 4 maintain a value corresponding to 10 ^8.6 Pa.s viscosity temperature). The shaft 33 then returns and the gate valve 18 is closed.

In the molding chamber 11, the cylinder 37 is activated to lower the upper mold shaft 38, and a pressure of 5000N is applied to the upper mold 3 until the lower surface of the flange fully contacts the upper surface of the mold 5, thereby molding the required precision glass product.

Then, the prepared glass product is cooled in the molding chamber 11 in the above-mentioned state. In this state, the lower surface of the flange of the mold 3 contacts the upper surface of the mold 25. During cooling, the lower mold cylinder 39 is activated to pass the shaft 40 with a force of 3000N. The pressure of the pressure upwardly presses the lower mold 4, so that the lower mold 4 follows the contraction of the molded glass product 24b.

Then, when the glass reaches a temperature corresponding to 10 ⁴ Pa.s, the pressurization by the lower mold cylinder 39 stops, and the upper mold cylinder 37 immediately moves upwards to lift the upper mold, which is fixed on the upper mold shaft 38 Upper cover 7 lifts its flange to reach.

Then the gate valve 19 is opened, and the demoulding cylinder 44 starts to move the suction jaw 46 arranged on the shaft 45 to a certain position above the lower mold 4, thereby sucking the glass 24b made. Then, the cylinder 44 returns to one position above the table 43. place, and the table drive cylinder 41 is activated to the position where the table 43 contacts the lower surface of the glassware 24b. In this position, the suction operation of the flange 46 is stopped. With the molded glass 24b supported on the stage 43, the cylinder 41 is activated to move the shaft 42 downward and the shaft 45 is retracted to the retracted position shown in FIG. 1 where the molded glass 24b is supported. Valve 19 is now closed, chamber lid 17 is opened, and molded glass 24b is removed from ejection chamber 12 by appropriate handling mechanisms. Then the cover 17 is closed, and the interior of the chamber 12 is replaced by the non-oxygen atmosphere through the aforementioned process to prepare for the next demoulding operation.

After continuously repeating the above-mentioned molding operation about 100 times, the precision glass product produced has no abnormality in appearance, and its precision surface is also very satisfactory, and its surface astigmatism and contour map have only one Newtonian earth ring or less, and , at this point molds 1, 2, 3 and 4 did not show any deposition of volatile species and were in a state where molding operations could continue.

Comparative example 1

In order to compare the operation of the present invention with the prior art, the prefabricated operation of the above-mentioned example 1 is reproduced with the same equipment, but the following process does not include vacuuming and introducing gas steps. In this case, after about 30 rounds, molds 1 and 2 were deposited with volatiles and could no longer provide a glass article with a satisfactory appearance.

Also, when the gas replacement was performed in the replacement chamber at a glass viscosity of 10 ⁸ Pa.s, the glass material 24a had a large number of bubbles generated inside the glass, and thus could not be used for molding.

Example 2

Referring to Figures 1-5, a specific example will be described with data. The same glass material in Example 1 is used to form the double-sided convex lens shown in Figure 3 with an effective diameter of 12mm and an outer diameter of about 16mm. The same steps as in Example 1 will not be explained. In this example, when the valves 18 and 19 were closed, the inner surface of the molding chamber 11 and the demoulding chamber 12 were vacuumed, and then filled with non-oxygen gas (nitrogen). And the upper mold heater 54 and the lower mold heater 55 are energized to heat the molds 3 and 4 to a temperature corresponding to the glass viscosity of 10 ^8.5 Pa.s.

Make the molten glass that viscosity is 10Pa.s flow out from outlet 22, as example 1, glass piece 24 is received by mold 1, puts into replacement chamber 10 afterwards, chamber lid 14 closes afterwards. Next, the mold 1 is heated to a temperature corresponding to the glass viscosity of 10 ⁸ Pa.s in the chamber 10 with nitrogen flow, and the heater 53 in the chamber 10 is energized to heat the atmosphere surrounding the glass block 24 to a temperature corresponding to 10 ⁴ Pa.s temperature of glass viscosity. Under the action of this heating operation and the heat contained in the block 24, it is further static gravimetrically deformed to a flatter state, close to the cohesive glass product 24d shown in Figure 5B, thereby obtaining a glass material 24c of a desired shape .

Then turn off the heater 53, and when the glass material 24c is cooled to a temperature corresponding to the viscosity of 10 ⁴ Pa.s, the replacement chamber 10 is evacuated and nitrogen gas is introduced, as described in Example 1, after such a gas replacement, The glass material is removed from the receiving mold 1 by, for example, the above-mentioned suction jaws, then passed from the chamber 10 to the chamber 11, placed on the lower mold 4 heated to a temperature corresponding to a viscosity of 10 ^8.5 Pa.s, and, on the mold 3 , 4 to withstand 4500N, 60 seconds of compression molding processing. After that, the molded article 24d was cooled, and the lower mold 4 was made to follow the shrinkage of the molded article with a pressure of 2000N. Then, the same method as described in Example 1, at the same temperature, passes through the demoulding chamber, and takes out the precision glass product from the molding chamber. The results obtained were the same as in Example 1.

Example 3

A different process for making a lens having the same shape from the same material as in Example 1 is described below with reference to FIGS. 1 and 4A-4C. As example 1, after the gate valves 18, 19 are closed, the inside of the chamber 11 and the chamber 12 are evacuated, then non-oxygen gas is introduced, the upper mold heater 54 and the lower mold heater 55 are energized, and the upper and lower molds 3, 4 are heated to A temperature corresponding to a glass viscosity of 10 ^8.2 Pa.s.

After the glass is melted in the furnace, the molten glass with a viscosity of 10 ^8.2 Pa.s flows out from the outlet 22, and the glass block 24 is received by the mold 1 and introduced into the replacement chamber 10 as in example 1. After the lid 14 is closed, the block 24 is The pre-molding is carried out with the mold 2 in the nitrogen flow of the displacement chamber 10 . In the chamber 10, the heaters 51, 52 are energized to heat the mold and glass material so that the receiving mold 1 and the upper mold 2 are heated to a temperature corresponding to the viscosity of the glass of 10 ⁹ Pa.s.

Even after pre-molding, the nitrogen supply to the chamber 10 is continued while maintaining electrical heating to avoid excessive cooling. When the oxygen concentration reaches 5PPm or less, the nitrogen supply is stopped. Then, the valve 18 is opened, and the pre-molded glass material 24a is transferred from the mold 1 of the displacement chamber 10 to the lower mold 4 of the molding chamber 11, as described in Example 1. In this state, the glass is at a temperature corresponding to a viscosity of 10 ⁸ Pa.s. The compression molding operation is performed at a pressure of 4500N for 45 seconds, and in the cooling step, the lower mold 4 can follow the contraction of the glass material 24a by the mold-glass adhesive force. Next, at a temperature corresponding to the viscosity glass of 10 ¹² Pa.s, the mold was opened, and the molded glass product 24b was taken out in the same manner as in Example 1. The results obtained were as satisfactory as in Example 1.

Example 4

This example shows the process of manufacturing a lens with the same shape as Example 2 with the same material as Example 1, but with a different method from Example 2. This process will be described in detail with reference to FIG. 1 and FIGS. 5A-5C. Like Example 1, after valves 18, 19 were closed, the inside of molding chamber 11 and demoulding chamber 12 were vacuumized and filled with non-oxygen (nitrogen) gas. At the same time, the upper mold heater 54 and the lower mold heater 55 are energized to heat the upper and lower molds 3 and 4 to a temperature corresponding to the viscosity of 10 ^8.2 Pa.s glass. Then similar to Example 1, after the glass is melted, the molten glass with a viscosity of 10 ^8.5 Pa·s flows out of the outlet 22 , and the glass block 24 is received by the mold 1 and introduced into the displacement chamber 10 . After the cover 14 is closed, the receiving mold 1 is heated to a temperature corresponding to the viscosity of 10 ⁷ Pa.s in the nitrogen gas filled in the chamber 10, and the heater 53 of the chamber 10 is charged at the same time, and the atmosphere around the block 24 is heated to a temperature corresponding to 10 ⁴ Temperature of Pa.s viscosity. Due to this heating and the heat contained in glass block 24, block 24 is further thermally deformed by dead weight to a flatter shape closer to precision glass article 24b, as shown in FIG. 5B, thereby preforming glass material 24a. When the oxygen concentration in the chamber 10 reaches 5ppm or lower, the nitrogen supply is stopped, the valve 18 is opened, and the preformed glass 24a is transferred from the chamber 10 to the lower mold 4 in the molding chamber in a manner similar to Example 1. In this state, the glass material is at a temperature corresponding to a viscosity of 10 ⁷ Pa.s. Molding is carried out under 3000N pressure for 30 seconds, and in the subsequent cooling step, the lower mold 4 is applied with 2000N pressure, and the glass viscosity is maintained at (10 ¹⁰ -10 ^12.5 ) Pa.s, so that the lower mold 4 can keep up with the upper material 24a shrink. Next, the mold was opened at a temperature corresponding to a viscosity of 10 ¹³ Pa·s, as in 1, and the fine glass product was taken out with satisfactory results as in Example 1.

In the aforementioned examples, the replacement chamber 10 is located directly below the glass outlet 22 , however, the chamber 10 can also be placed in a different direction, and the receiving mold 1 can be extended obliquely from the chamber 10 to a position below the outlet 22 . Thus, it is also possible to provide a plurality of molding apparatuses to one melting furnace, and to sequentially supply molten glass to the receiving molds of these molding apparatuses, thereby increasing throughput and improving productivity.

An example of the temperature control of the material and the mold in the molding operation of the glass frit (pre-system) of the present invention will be described in detail below with reference to FIGS. 8-15. This process comprises the steps (A): receiving a predetermined amount of molten glass from a melting furnace at a temperature corresponding to a viscosity of 10 ^-2 -10 ⁴ dPa.s; and step (B) adjusting the temperature of said glass to a temperature corresponding to 10 ⁴ - 10 ¹⁰ dPa.s viscosity temperature; step (C): supply the glass to a mold whose temperature is adjusted to correspond to the glass viscosity of 10 ¹¹ -10 ¹⁴ dPa.s, and step (D): use the mold to mold the glass Molded.

If necessary, step (E) is also included: after molding, the molded glass product is released from the mold, and the glass temperature corresponds to a viscosity of 10 ¹⁰ -10 ¹³ dPa.s at this time; step (F) cooling the molded glass product, the temperature drop rate At least 10°C/min, at least cooled to a temperature corresponding to the viscosity of 10 ¹⁴ dPa.s, due to the viscosity of the demolded glass product, it may still be deformed due to weight, and step (F) is performed outside the mold to prevent this out of shape.

Preferred embodiments of steps (A)-(F) are described below. In step (A), from the molten state of the glass, take out the required amount of glass at a temperature corresponding to the viscosity of 10 ^-2 -10 ⁴ dPa.s, and, in the case of the glass flowing from the outlet of the melting furnace, a temperature control can be set near the outlet Mechanism to control the dripping of molten glass in the above temperature range. The temperature preferably corresponds to the 10 ^1.6 -10 ^2.6 dPa.s glass viscosity region.

In step (B), the temperature of the removed glass is adjusted to correspond to the viscosity region of 10 ⁴ -10 ¹⁰ dPa.s, and this temperature adjustment can be achieved, for example, by blowing cooling gas through the glass as it falls from the outlet. This temperature preferably corresponds to a viscosity of 10 ⁶ -10 ⁸ dPa.s, most preferably 10 ⁷ -10 ⁸ dPa.s.

In step (C), the thus temperature-controlled glass is put into a press mold, and the temperature of the press mold is adjusted to a temperature corresponding to a glass viscosity of 10 ¹¹ -10 ¹⁴ dPa.s, preferably corresponding to 10 ¹¹ -10 ¹³ dPa .s, a viscosity of 10 ^11.2 -10 ¹² is optimal, and the temperature difference between the mold and the glass is preferably at least a temperature corresponding to a viscosity of 10 ³ dPa.s.

In step (D), the glass is pressed under a load applied to the mold, preferably by maintaining the surface of the mold pressed against the glass, making intimate contact at least where the glass is required to form the precise shape.

In step (E), the molded glass is ejected from the mold at a temperature corresponding to a viscosity of 10 ¹⁰ -10 ¹³ dPa·s. If, during compression molding, the glass reaches this temperature due to heat removal to the mold, the glass can be removed from all molding surfaces individually. This temperature preferably corresponds to a viscosity of 10 ^10.5 - 10 ^11.5 dPa.s.

In step (F), the demolded glass is cooled at a cooling rate of at least 10°C/min to a temperature corresponding to a viscosity of at least 10 ¹⁴ dPa·s, and said cooling can be achieved, for example, by cooling gas.

The compression mold used in the present invention is preferably corrected in advance according to the difference in shape between the mold and the molded product, which depends on the molding conditions such as temperature, pressure, cooling rate and the shape of the glass product, so that ideal molding accuracy can be guaranteed. These data settings and temperature zone control are naturally determined according to the type and composition of the glass used.

Example 5:

In order to understand the above-mentioned molding process, Figs. 8A-8E show a molding structure as an example, wherein a glass melting furnace 101 is shown; an optical glass material 102 (SK12; manufactured by Ohara Optical Co., Ltd.) in a molten state; a discharge pipe 103; a discharge port 103a; A glass preform 104; cooling gas 105; lower mold 106; upper mold 107; release plate 108; molten glass product 109;

In this example, the outlet 103a is temperature controlled according to Fig. 8A, the temperature of the dropped glass 104 is controlled to be 1180°C (corresponding to a viscosity of 10 ^2.1 dPa·s), and a glass droplet of 850 mm ³ is obtained. The glass preform 104a obtained in this way is cooled to 750°C (corresponding to a viscosity of 10 ^5.8 dPa.s) by the gas 105 during the dropping process, and sent to the lower mold 106, as shown in Figure 8B, the lower mold 106 and the upper mold 107 It was previously controlled at a temperature of 580°C (corresponding to a glass viscosity of 10 ^11.3 dPa.s).

Immediately after sending the glass to the mold, a pressure of 2000N was applied for 20 seconds, as shown in Fig. 8C. During operation, the temperature of the glass surface in contact with the mold drops to 604°C instantaneously, which is lower than the mold corrosion temperature. Thereafter the glass preform is deformed and heat is taken away by the upper and lower dies, and reaches 590°C (corresponding to a glass viscosity of 10 ^10.8 dPa·s) at the end of the molding operation.

After the molding operation, the upper mold 107 is raised as shown in FIG. 8D , and the release plate 108 connected thereto is used to separate the pressed lens 109 from the lower mold 106 . If the lens remains stuck to the upper mold 107, the lens 109 can be separated from the upper mold 107 with a cylindrical mold 110 shown in FIG. 8E. The lens is then removed and cooled, for example with cooling gas, to 485° C. within two minutes (corresponding to a glass viscosity of 10 ^15.5 dPa.s), at which point no further deformations by the glass weight can occur.

The astigmatism and surface profile of the spherical concave lens obtained from this example (see Figure 9) has 0.5 Newton rings or less, and its radial component of curvature has two Newton rings or less.

The radius of curvature of the upper and lower dies 106, 107 used in the present invention is 30.11 mm, and the central area has a smaller radius of curvature than the surface profile of the peripheral area, as shown in Figure 10 (measured with a Fizeau interferometer). Lenses made with molds that do not have such a profile will have a non-ideal profile, and the mold used has been calibrated in advance to avoid this non-ideal surface profile.

Example 6

Figures 11A-11E show the steps of this example, and Figure 12 shows the form of the smaller-diameter positive lens produced in this example to confirm the precision of size transfer. The glass material is the same as Example 5. The glass 112 shown in Fig. 11A is dropped from the outlet 111a, its temperature is controlled at 1320°C (corresponding to the viscosity of 10 ^1.6 dPa.s) and it is 25 mm ³ drops, and the glass preform 112a thus obtained is heated by the heating gas 113 during the dropping process. Control to 840°C (corresponding to 10 ^4.4 dPa.s viscosity). Compared to Example 5, heated gas is used because the glass preform 112a is smaller and the temperature becomes too low before it is sent to the mold.

The glass preform 104a thus obtained is fed into the lower mold 114 as shown in Fig. 11B, and the lower and upper molds 106, 107 are previously heated to 580°C (corresponding to a viscosity of 10 ^11.8 dPa·s).

Immediately after the glass is fed into the mold, a pressure of 500N is applied for 10 seconds, as shown in Figure 11C, the glass surface close to the mold during molding is instantly cooled to 616°C, which is lower than the erosion temperature. The glass preform is then deformed by the upper and lower molds and takes away the heat, so that it is cooled to 595°C (corresponding to a viscosity of 10 ^10.8 dPa.s) at the end of the molding operation.

After the molding operation, as shown in FIG. 1D , the upper mold 115 is raised, and the release plate 116 connected thereto is used to separate the molded lens 117 from the lower mold 114 . If the lens continues to stick to the upper mold 115 at this time, it can be separated by the cylindrical mold 118, as shown in FIG. 11E. The lens is then removed and cooled, for example with cooling gas, to 485° C. (corresponding to a viscosity of 10 ^15.5 dPa.s) within 2 minutes, at which point no weight-induced deformation is possible anymore.

The astigmatism and surface profile of the smaller diameter positive lens (see Fig. 12) obtained by the present invention is 0.5 Newton Rings or less, and has satisfactory curvature radial component accuracy of 2 Newton Rings or less.

In this example, upper and lower die 114, 115 radii are respectively 3.512mm and 7.024mm, unlike Example 5, the surface contour figure must be corrected, because the positive lens does not produce the surface contour figure, but may be accompanied by changes in the radius of curvature, unless such as Molding conditions such as temperature, pressure, cooling rate, etc. are greatly changed.

Example 7

Figures 13A-13E show the steps of this example, and Figure 14 shows the crescent lens produced in this example to demonstrate the shape transfer accuracy. The glass material used in this example is the same as Example 5. As shown in Figure 11A, the glass is dropped from the outlet 119a, and its temperature is controlled at 1120°C (corresponding to the glass viscosity of 10 ^2.3 dPa.s), to obtain a glass droplet of 1430mm ³ , and the glass preform 120a thus obtained is cooled during the dropping process The gas is cooled to 700°C (corresponding to a glass viscosity of 10 ^7.1 dPa.s) and sent to the lower die 122 as shown in 13B. The lower and upper molds 122, 123 were preheated to 570°C (corresponding to a viscosity of 10 ^11.7 ).

Immediately after the glass was fed into the mold, a pressure of 4000N was applied for 30 seconds, as shown in Figure 13C. During the molding process, the glass surface next to the mold is instantaneously cooled to 588°C, which is lower than the mold erosion temperature. The glass preform is then deformed by the upper and lower molds and takes away heat so that its temperature reaches 585°C (corresponding to a viscosity of 10 ¹¹ dPa.s) at the end of the molding operation.

After the molding operation, the upper mold 123 is raised, as shown in FIG. 13D, and the release plate 124 connected thereto is used to separate the lens 125 from the lower mold. At this time, if the lens continues to stick to the upper mold 123, the lens can be separated from the upper mold with a cylindrical mold 126, as shown in FIG. 10 ^15.5 dPa.s viscosity), at this time the deformation caused by the weight of the glass will no longer occur.

The astigmatism and surface profile of the crescent lens obtained in this example (see Fig. 14) was 0.5 N rings or less, and the viscosity of the radial component of curvature was satisfactory: 2 N rings or less.

The radii of curvature of the upper and lower molds 122 and 123 used in this example are 112.04mm and 57.04mm respectively, and the radius of curvature of the edge area in the surface profile diagram is smaller than that of the central area (measured with a Fizeau interferometer), as shown in Figure 15A, 15B. Molding with a mold that does not have such a surface profile will produce a molded lens with a surface profile, and the mold is calibrated in advance to avoid this phenomenon.

As described above, the present invention provides a method for producing precision glass products using molten glass in a series of steps including molding: reception by a receiving mold; flow of a predetermined amount of molten glass from the outlet of a furnace; A certain amount of molten glass is sent into the replacement chamber; the molten glass is preformed to a predetermined shape in the replacement chamber; the airtight state in the replacement furnace is maintained and a vacuum is drawn; non-oxygen gas is introduced into the replacement chamber; The glass is pressed into a predetermined shape in a non-oxygen atmosphere in the connected compression molding chamber. At the same time, a method is also provided, including: receiving with a receiving mold, and a predetermined amount of molten glass flows out from the outlet of the furnace; sending the receiving mold and a predetermined amount of molten glass received on it into a replacement chamber; Pre-forming the molten glass into a predetermined shape; before, after or during the above-mentioned preparation of the molten glass, filling the replacement chamber with non-oxygen gas; pressing the desired shape under the non-oxygen atmosphere in the compression molding chamber connected to the replacement chamber Precision glass products. This makes it possible to prevent contamination of the inside of the molding apparatus such as the displacement chamber or the molding chamber due to volatile substances generated from the glass flowing out of the glass outlet. At the same time, the continuous production method from molten glass to precision glass products allows effective use of the thermal energy of molten glass and enables high-efficiency continuous molding operations.

Moreover, the present invention also provides a method for producing precision glass products from molten glass, the method comprising a series of steps of molding: the molten glass flowing out from the outlet of the melting furnace is divided into a predetermined amount and adjusted to correspond to 10 ⁴ - a temperature of 10 ¹⁰ dPa.s glass viscosity; feeding said glass into a mold whose temperature is adjusted to correspond to a viscosity of 10 ¹¹ -10 ¹⁴ dPa.s; and pressing said glass with said mold. This makes it possible to prevent heat damage or damage to the molded product during the molding operation, and to prolong the life of the mold even with a short molding cycle, and to economically produce high-precision molded optical glass products.

Claims (12)

1. A method for producing precision glass products with molten glass, characterized in that the method comprises a series of steps including a molding step: receiving a predetermined amount of molten glass with a receiving mold, which flows out from a glass outlet of a melting furnace; Sending the receiving mold and a predetermined amount of molten glass received thereon into a replacement chamber; pre-forming the molten glass into a predetermined shape in the replacement chamber; evacuating the interior of the replacement chamber; filling the replacement chamber with non-oxygen gas; In a molding chamber communicated with the replacement chamber and maintaining a non-oxygen atmosphere, the precise glass product of the desired shape is pressed. 2. The method according to claim 1, wherein the evacuation of the displacement chamber is performed at a time when the glass surface reaches a temperature corresponding to a glass viscosity of 10 ⁵ dPa·s or higher. 3. A method for producing precision glass products from molten glass, characterized in that the method comprises a series of steps including a molding step: receiving a predetermined amount of molten glass with a receiving mold, which flows out from a glass outlet of a melting furnace; feeding the receiving mold with a predetermined amount of molten glass received thereon into a displacement chamber; preforming the molten glass into a predetermined shape in the displacement chamber; before, after or during said glass preforming step, filling the displacement chamber with non-oxygen gas; and pressing a precision glass article of desired shape in a molding chamber communicated with the displacement chamber and maintaining a non-oxygen atmosphere. 4. A method according to any one of claims 1-3, characterized in that the preforming takes place in the displacement chamber using a receiving mold on which the molten glass is supported, and an upper mold opposed thereto. 5. The method according to any one of claims 1-3, characterized in that the pre-shaping in the replacement chamber is completed by adjusting the temperature of the receiving mold and the molding atmosphere of the replacement chamber, using another glass surface opposite to the receiving mold. The surface tension of a surface causes the molten glass to form a substantially spherical shape. 6. The method according to any one of claims 1-5, characterized in that the step of pressing a precision glass product in a molding chamber maintaining a non-oxygen atmosphere comprises: heating said mold to a predetermined temperature; The displacement chamber is fed into the molding chamber and placed on one of the lower molds in the mold; the glass is molded by pressurizing an upper mold in the mold; while the molded glass remains in the molding chamber, cooling it; and, separating the molded glass article from the mold, cooling it to the desired temperature, and removing it from the molding chamber. 7. A method according to claim 6, characterized in that the cooling step carried out while the glass is still in the molding chamber includes a step of fitting the glass to the mold during cooling. 8. The method of claim 7, wherein the step of fitting the glass to the mold comprises applying a desired pressure to the mold. 9. The method of claim 7, wherein the step of fitting the glass to the mold is a step performed by mutual adhesion between the glass and the mold. 10. A method of producing precision glass products from molten glass, characterized in that the method comprises a series of steps including a molding step: separating a predetermined amount of molten glass, which flows out from the glass outlet of the melting furnace, and melting the molten glass The glass is adjusted to a temperature corresponding to a glass viscosity of 10 ⁴ -10 ¹⁰ dPa.s; the glass is fed into a mold which is adjusted to a temperature corresponding to a glass viscosity of 10 ¹¹ -10 ¹⁴ dPa.s; and, pressed with the mold the glass. 11. A method according to claim 10, further comprising a step of withdrawing the molten glass by allowing the glass to flow out of the furnace outlet at a temperature corresponding to a glass viscosity of 10 ^-2 -10 ⁴ dPa.s. 12. The method according to claim 10 or 11, further comprising the step of: after the glass is molded in the mold, when the molded glass product is at a temperature corresponding to a glass viscosity of 10 ¹⁰ -10 ¹³ dPa.s, taking it out of the mold; and, cooling the molded glass article thus taken out with a temperature gradient of not less than 10°C/minute to a temperature lower than the temperature corresponding to the glass viscosity of 10 ¹⁴ dPa·s.

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