CN110803861A - A large-size chalcogenide glass forming method and special large-diameter forming mold - Google Patents

Abstract

The name of the invention is a large-size chalcogenide glass forming method and a special large-diameter forming mold, which belong to the technical field of chalcogenide glass forming. It mainly solves the problems that the existing large-size chalcogenide glass is difficult to form and its quality is difficult to guarantee. It is characterized in that the method of multiple hot pressing is adopted. First, the surface of the chalcogenide glass blank is ground, the mold cavity is sprayed with a release agent, the glass blank is placed in the molding mold, and then placed in a molding furnace, and the process is performed. The glass blank is softened at a high temperature, and the blank is softened into the shape of the mold under the pressure of the upper mold's own weight, and the heating is stopped. When the mold is lowered to room temperature, the softened glass blank is taken out; secondly, the above operations are repeated until the blank is softened. , start the press, and press repeatedly for many times, so that the soft blank is formed into the cavity size of the mold, and finally a large-size chalcogenide glass is obtained. The method is simple and convenient to operate, and can be formed quickly and accurately, and is mainly used for preparing large-diameter optical chalcogenide glass.

Description

A large-size chalcogenide glass forming method and special large-diameter forming mold

technical field

The invention belongs to the technical field of chalcogenide glass forming, and in particular relates to a method for preparing large-diameter chalcogenide glass and a large-diameter forming mold specially used for the method.

Background technique

Chalcogenide glass is a new type of infrared material. It has excellent infrared transmittance in the 3~5μm and 8~14μm bands. Various shapes of infrared optical components can be prepared by post-press molding. The processing method has the advantages of simplified process, low cost and high efficiency, and has been widely used in military and civilian fields so far.

With the continuous expansion of the application field of chalcogenide glass, the market has a strong demand for large-size chalcogenide glass. At present, because the chalcogenide glass is melted by melting and quenching method, the raw materials are mainly put into ampoules for vacuum sealing, and then put into a swing furnace for melting, so the diameter of the chalcogenide glass blank cannot be enlarged. At the same time, many research institutions and enterprises at home and abroad have studied a method of leakage molding to prepare large-sized chalcogenide glass. However, due to the serious volatilization of chalcogenide glass at high temperature and the strict requirements on melting equipment and environment, it is difficult for leakage molding to produce good streaks. , Chalcogenide glass blank with good uniformity. Therefore, the preparation of large-scale chalcogenide glass becomes a bottleneck problem.

Patent 201610380736.5 discloses a molding method of chalcogenide glass. This invention mainly uses quartz molds to form large-diameter chalcogenide glass with a size of Φ120mm through one-time hot pressing in a vacuum state. The quartz mold used in this method has poor thermal conductivity, is fragile, and has a short life, and it is difficult for quartz to process larger diameters. At the same time, this method needs to be formed in a vacuum state, which requires high equipment and causes high cost, and can only form chalcogenide glass products with a diameter of Φ120mm or less at one time. The molds and molding methods used are different from those of the present invention.

Patent 201611026723.4 discloses a preparation method of large-size chalcogenide glass. The invention adopts the single-crucible leakage method. After the glass raw material is melted, it is homogenized by a stirrer, and finally the glass liquid is leaked into the forming mold, thereby producing large-sized chalcogenide glass. This invention adopts the method of direct leakage injection molding of glass liquid. Since the raw materials used for the chalcogenide glass are all volatile raw materials, the final obtained chalcogenide glass is prone to volatilization and casting streaks, the yield is low, and the production cost is high. Drop-shot and continuous-melting technologies are still in the conceptual stage and have not been put into production applications. The molding method used is different from the present invention.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a large-size chalcogenide glass forming method and a large-diameter forming mold specially used for the method. The method is simple and convenient to operate, and can quickly and accurately form large-size chalcogenide glass. Compared with the large-size chalcogenide glass formed by direct leakage injection of the molten glass, this method can effectively avoid the problems of internal stripes and poor optical uniformity caused by the volatilization of the molten glass. Folding, rounded edges and other forming problems occur, and the internal quality and performance of the formed products are equivalent to glass blanks, which are suitable for the forming of various large-size chalcogenide glass. The "large size" or "large diameter" mentioned in the present invention means that the diameter of the round glass, the side length of the rectangular glass or the length of the connecting line between the maximum points of the non-irregular shape is greater than or equal to 120mm.

The basic idea of the present invention is: through the long-term production of chalcogenide glass, it is found that the chalcogenide glass often has rounded edges (not completely filled), folding, etc. Poor molding; and the chalcogenide glass leakage technology is not mature, the volatilization streak of chalcogenide glass directly poured from the glass liquid cannot be solved, the material shape is short, and the viscosity is not easy to control, so there are big problems. Therefore, the present invention intends to adopt multiple forming methods. First, by calculating the required weight of large-diameter chalcogenide glass, a traditional melting process is selected to prepare a chalcogenide glass blank. Secondly, design and manufacture the corresponding forming mold, choose the self-made pressing furnace, put the blank into the mold, and then put the mold into the pressing furnace. To prepare qualified large-size chalcogenide glass, in the present invention, at a certain temperature, the blank is firstly spread softly under the upper mold and its own gravity, without opening the press for forming, and after the softening is completed, the surface of the spread soft material is processed. Processing, and then the second softening, this process starts the press for pressing, and finally, accurately shapes the large-sized chalcogenide glass that matches the size of the mold.

The technical key of the present invention is to prepare qualified blanks for large-size chalcogenide glass by traditional mature melting method, use sandpaper to polish the surface, and coat with release powder; further design and produce corresponding large-size glass. Chalcogenide glass forming mold, spray the mold release agent on the surface of the mold, put the polished blank into the mold; further put the mold into the pressing furnace, soften and deform the chalcogenide glass blank at a certain process temperature, and keep it for a period of time After the time, the power supply of the press is cut off; the softened chalcogenide glass blank is further taken out, the surface of the blank is polished again, and the mold is re-sprayed with release agent; the blank and the mold are further put into the pressing furnace for a second time Pressing, setting press parameters and process parameters, after the blank is softened to a certain extent, start the press to press, and then prepare a large-size chalcogenide glass product. The large-size chalcogenide glass molding method of the present invention solves the molding bottleneck of large-size infrared products for special purposes. Compared with the large-size chalcogenide glass described in many patents, which is directly leak-injected, this method can effectively avoid problems such as internal stripes and poor optical uniformity caused by the volatilization of the glass. Folding, rounded edges and other poor forming problems occur in large-scale molding, and the internal quality and performance of the molded products are equivalent to glass blanks, which are suitable for the molding of various large-size chalcogenide glass.

The technical solution of the molding method of the present invention is as follows: a large-size chalcogenide glass molding method, which is characterized by comprising the following steps: first, the surface of the chalcogenide glass blank is polished with sandpaper and coated with release powder at one time, and the surface of the chalcogenide glass blank is polished once with sandpaper and coated with release powder. The inner cavity of the forming mold is evenly sprayed with release agent, and the polished chalcogenide glass blank is placed in the large-diameter forming mold; second, the large-diameter forming mold with the chalcogenide glass blank is placed in the molding furnace, and the temperature is heated to make it The chalcogenide glass blank is softened, and the chalcogenide glass blank is spread out under the pressure of the upper mold's own weight to a shape close to the cavity size of the large-diameter forming mold and then stops heating; thirdly, after the temperature of the large-diameter forming mold has dropped to room temperature, take out the spread For soft chalcogenide glass blanks, use sandpaper to grind the removed chalcogenide glass blanks for a second time and apply release powder. Spray the mold release agent evenly in the cavity of the large-diameter forming mold, and place the secondary polished chalcogenide glass blanks in the In the large-diameter forming mold; fourth, place the large-diameter forming mold equipped with the secondary grinding chalcogenide glass blank in the molding furnace, and after heating to the molding temperature, start the press to form the soft chalcogenide glass blank. The size of the inner cavity of the large-diameter forming mold is formed, and the large-sized chalcogenide glass is obtained.

Further, the method for forming large-size chalcogenide glass is characterized in that the fourth step is: fourth, placing a large-diameter forming mold with a secondary polished chalcogenide glass blank in a molding furnace, and adding After the temperature reaches the molding temperature, the press is started, and the pressing is repeated for many times, so that the soft chalcogenide glass blank is formed into the cavity size of the large-diameter molding mold, and then the large-size chalcogenide glass is obtained.

Further, the large-size chalcogenide glass forming method is characterized in that the mesh number of the sandpaper is 150-300 mesh; the mesh number of the sandpaper in the third step is smaller than the mesh number of the sandpaper in the first step.

Further, the large-size chalcogenide glass forming method is characterized in that the release powder is an inorganic powder, and the release agent is an inorganic solvent.

Further, the large-size chalcogenide glass forming method is characterized in that the forming temperature is 50-80°C above the softening temperature of the chalcogenide glass, and the forming mold is composed of three parts: a mold sleeve, an upper mold, and a lower mold. The material is alloy material.

Further, the repeated pressing is 2 to 6 times; after repeated pressing, the temperature is kept for 0.5 to 5 hours, and the pressure is maintained for 10 to 30 s.

Further, the large-size chalcogenide glass forming method is characterized in that in the second step, the softening temperature of the chalcogenide glass blank is calculated according to the thickness of the glass after forming.

Further, the large-size chalcogenide glass forming method is characterized in that the chalcogenide glass blank is made by a melting and quenching method; the weight of the chalcogenide glass blank is the same as the weight of the large-size chalcogenide glass to be formed.

The technical solution of the forming mold of the present invention is as follows: a large-diameter forming mold specially used for the above-mentioned large-size chalcogenide glass forming method, which is characterized in that: it includes an upper mold, a mold sleeve and a lower mold; the cross section of the inner cavity of the mold sleeve The size is the same as the cross-sectional size of the large-size chalcogenide glass to be formed, the upper end of the mold sleeve is provided with an upper opening with the same size as the cross-sectional size of the inner cavity, and the lower end of the mold sleeve is provided with a lower opening smaller than the cross-sectional size of the inner cavity; the upper mold is A columnar body with the same cross-sectional dimension as the inner cavity of the die sleeve; the upper part of the lower die is a columnar body with the same cross-sectional dimension as the inner cavity of the die sleeve, and the lower part is a columnar body matched with the lower opening of the die sleeve .

Further, the large-diameter forming mold is characterized in that the weight of the upper mold is 2-5 times the weight of the large-sized chalcogenide glass to be formed.

The forming method of the invention has the characteristics of simple and convenient operation, and can quickly and accurately form large-sized chalcogenide glass. The invention is mainly used for preparing large-diameter optical chalcogenide glass.

Description of drawings

FIG. 1 is a schematic structural diagram of a large-diameter molding die used in Embodiment 1 of the present invention.

FIG. 2 is a comparison diagram of the infrared transmittance curves of the chalcogenide glass before and after molding of Example 1 of the present invention.

In the picture: 1. Upper mold; 2. Chalcogenide glass blank; 3. Mold sleeve; 4. Lower mold.

Detailed ways

Example 1 is a typical test of the present invention for illustrating the formation of large size chalcogenide glass. Embodiment 1 is only for demonstrating technical feasibility, and the present invention is not limited to this embodiment. The qualified blanks for large-size chalcogenide glass are prepared by traditional mature melting methods, and the surface is polished with sandpaper and coated with release powder; further design and production of corresponding large-size chalcogenide glass forming molds , spray the mold release agent on the surface of the mold, put the polished blank into the mold; further put the mold into the pressing furnace, soften and deform the chalcogenide glass blank at a certain process temperature, keep it for a period of time, break it Press power supply; further take out the softened chalcogenide glass blank, grind the surface of the blank again, and spray the mold release agent again; further put the blank and mold into the pressing furnace for multiple pressing, set the pressure Machine parameters and process parameters, after the blank is softened to a certain extent, start the press to press, and then prepare a large-size chalcogenide glass product.

The large-diameter forming mold used in the large-size chalcogenide glass forming method of the present invention includes an upper mold 1 , a mold sleeve 3 and a lower mold 4 . The cross-sectional size of the inner cavity of the mold sleeve 3 is the same as the cross-sectional size of the large-size chalcogenide glass to be formed. The upper end of the mold sleeve 3 is provided with an upper opening with the same size as the cross-sectional size of the inner cavity, and the lower end of the mold sleeve 3 is provided with a smaller size than the cross-sectional size of the inner cavity. the lower opening. The upper die 1 is a cylindrical body with the same cross-sectional dimension as the inner cavity of the die sleeve 3 . The upper part of the lower die 4 is a columnar body with the same cross-sectional dimension as the inner cavity of the die sleeve 3 , and the lower part is a columnar body matched with the lower opening of the die sleeve 3 . The cross section of the cavity of the mold sleeve 3 can be circular, rectangular or irregular. The weight of the upper mold 1 is 2-5 times the weight of the large-sized chalcogenide glass to be formed, so that the self-weight of the upper mold 1 can soften the heated chalcogenide glass blank 2 in the cavity of the mold sleeve 3 to be close to the inside of the mold sleeve 3. Cavity size. The upper die 1, the die sleeve 3 and the lower die 4 are made of alloy materials.

The large-size chalcogenide glass forming method of the present invention comprises the following steps:

1) According to the theoretical calculation of the required weight of the large-size chalcogenide glass to be formed, the chalcogenide glass blank block is prepared by the traditional melting and quenching method;

2) Use 150~300 mesh sandpaper to grind the surface of the chalcogenide glass blank to remove pits, microcracks, broken edges and other defects on the surface of the blank, and coat with boron nitride powder;

3) After disassembling the large-diameter forming mold, preheat it at a temperature of 80-200 °C, and use a watering can to spray the release agent evenly on the inner surfaces of the upper mold 1, the lower mold 4, and the mold sleeve 3, and then combine the molds;

4) Slowly put the polished chalcogenide glass blank 2 in the middle of the lower mold of the mold, put it into the upper mold 1, and according to actual needs, draw a line on the exposed part of the upper mold 1 to determine the degree of softening of the blank;

5) Put the mold into the pressing furnace, set the temperature to be 50°C to 80°C above the softening temperature of the chalcogenide glass, the holding time is 0.5~5h, and the pressure holding time is 10~30s;

6) Execute the pressing process. After the temperature reaches the set process, the chalcogenide glass blank 2 is softened under the gravity of the upper die 1. After the upper die 1 moves down to the scribed position, the pressing machine is not started this time, and it is directly cut off. power supply, so that the chalcogenide glass blank 2 is naturally cooled to room temperature along with the mold;

7) Take out the chalcogenide glass blank that has been softened by the first temperature rise, and repeat steps 2 to 5. After the process is executed, after the chalcogenide glass blank is softened to the scribed position, start the press cylinder and carry out the second pressing. The pressing action can be repeated 2 to 6 times to ensure that the blank is completely formed into the mold size, thereby preparing large-sized chalcogenide glass.

Example 1: Preparation of commercial Φ200×20mm large-size As ₄₀ Se ₆₀ chalcogenide glass.

1) According to the theoretical calculation, the weight required for forming Φ200×20mm large-size As ₄₀ Se ₆₀ chalcogenide glass is 2907.6g, and the corresponding weight of Φ100×38 mm chalcogenide glass blank block was prepared by traditional melting and quenching method.

2) First, use 150-mesh coarse sandpaper to polish the larger defects on the surface of the blank, and then use 280-mesh fine sandpaper for fine grinding to remove pits, micro-cracks, broken edges and other defects on the surface of the blank to ensure that the surface is relatively smooth. On boron nitride powder.

3) Prepare the pre-designed Φ200 chalcogenide glass forming mold, disassemble the mold and preheat at 180 °C, and use a watering can to spray the boron nitride solvent evenly on the upper mold, the lower mold, and the mold sleeve. surface, and the mold is assembled.

4) Slowly put the polished chalcogenide glass blank in the middle of the lower mold of the mold, put it into the upper mold, and draw a line with paint strokes on the upper mold and the outer leakage part of the mold sleeve to observe the downward movement for judgment. degree of softening.

5) Put the mold into the pressing furnace, set the molding temperature to 290 °C (As ₄₀ Se ₆₀ glass Ts is 216 °C), the holding time is 2h, and the pressure holding time is 30s.

6) Carry out the pressing process. After the temperature reaches the set process, the blank is softened under the gravity of the upper mold. After the upper mold is softened to the scribed position, the power supply is directly cut off manually, so that the blank is naturally cooled to room temperature with the mold;

7) Take out the glass blank softened for the first time, and repeat steps 2 to 5. After the process is executed, after the upper die is found to move down, start the press cylinder to press, and repeat the pressing action twice to ensure that the blank is completely formed The size of the mold was obtained, so as to prepare a large-size chalcogenide glass of Φ200×20mm.

Claims (10)

1. A large-size chalcogenide glass forming method is characterized in that comprising the following steps: First, the surface of the chalcogenide glass blank is polished once with sandpaper and coated with release powder, and the inner cavity of the large-diameter molding die is evenly sprayed and demolded. Then, place the polished chalcogenide glass blank in a large-diameter forming mold; secondly, place the large-diameter forming mold with the chalcogenide glass blank in a molding furnace, and heat it to soften the chalcogenide glass blank. The glass blank is softened to a shape close to the cavity size of the large-diameter forming mold under the pressure of the upper mold's own weight, and then the heating is stopped; Sand the chalcogenide glass blank taken out with sandpaper for a second time and apply release powder, spray the release agent evenly in the cavity of the large-diameter forming mold, and place the chalcogenide glass blank after secondary grinding in the large-diameter forming mold; fourth , place the large-diameter forming mold with the secondary grinding chalcogenide glass blank in the molding furnace, and start the press after heating to the molding temperature, so that the soft chalcogenide glass blank is formed into the large-diameter forming mold cavity. size to obtain large-size chalcogenide glass. 2. A large-size chalcogenide glass forming method according to claim 1, characterized in that the fourth step is: fourth, placing the large-diameter forming mold with the secondary grinding chalcogenide glass blank on the In the molding furnace, after heating to the molding temperature, the press is started, and the molding is repeated many times, so that the soft chalcogenide glass blank is formed into the cavity size of the large-diameter molding mold, and then the large-size chalcogenide glass is obtained. 3. A large-size chalcogenide glass forming method according to claim 1 or 2, characterized in that: the mesh number of the sandpaper is 150-300 mesh; the mesh number of the sandpaper in the third step is smaller than that of the first step Mesh of medium sandpaper. 4. A large-size chalcogenide glass forming method according to claim 1 or 2, characterized in that: the release powder is an inorganic powder, and the release agent is an inorganic solvent. 5. A large-size chalcogenide glass forming method according to claim 1 or 2, characterized in that: the forming temperature is 50-80°C above the softening temperature of the chalcogenide glass. The lower mold consists of three parts, and the mold material is alloy material. 6 . The large-size chalcogenide glass forming method according to claim 2 , wherein the repeated pressing is 2 to 6 times; after the repeated pressing, the temperature is maintained for 0.5 to 5 hours, and the pressure is maintained. 10~30s. 7 . The large-size chalcogenide glass forming method according to claim 1 or 2 , wherein in the second step, the softening temperature of the chalcogenide glass blank is calculated according to the thickness of the glass after forming. 8 . 8. A large-size chalcogenide glass forming method according to claim 1 or 2, characterized in that: the chalcogenide glass blank is made by melting and quenching; The dimensions of the chalcogenide glass are the same in weight. 9. A large-diameter forming mold specially used for the large-size chalcogenide glass forming method according to claims 1 to 8, characterized in that it comprises an upper mold (1), a mold sleeve (3) and a lower mold (4) ; The size of the cross section of the inner cavity of the mold sleeve (3) is the same as that of the large size chalcogenide glass to be formed, and the upper end of the mold sleeve (3) is provided with an upper opening with the same size as the cross section of the inner cavity, and the mold sleeve (3) The lower end is provided with a lower opening smaller than the cross-sectional dimension of the inner cavity; the upper die (1) is a columnar body with the same cross-sectional dimension as the inner cavity of the die sleeve (3); the upper part of the lower die (4) is A cylindrical body with the same cross-sectional dimension as the inner cavity of the die sleeve (3), and the lower part is a cylindrical body matched with the lower opening of the die sleeve (3). 10 . The large-sized chalcogenide glass forming method according to claim 9 , wherein the weight of the upper mold ( 1 ) is 2-5 times the weight of the large-sized chalcogenide glass to be formed. 11 .