A microcrystalline glass filament production apparatus and method

Abstract

This invention discloses a microcrystalline glass filament-making equipment and method, relating to the technical fields of electronic glass manufacturing and glass testing equipment. It includes a high-temperature furnace, a positioning refractory platform, a crucible, a furnace top blind plate, a filament-making chamber, an air inlet, a glass door for the filament-making chamber, a clamping platform, a corundum rod, a lifting screw, an air outlet, and a positioning slide rod. This invention achieves rapid cooling of the microcrystalline glass during filament-making by precisely controlling key parameters such as temperature, gas flow rate, and stretching speed, combined with rapid cooling technology for flowing gas, effectively preventing crystallization. This invention can repeatedly produce high-quality glass filaments with a diameter less than 2 mm, controllable length, and uniformity without crystallization, significantly improving the success rate and efficiency of filament-making and solving the technical problem of uncontrollable microcrystalline glass filament-making processes.

Description

Technical Field

[0001] This invention relates to the technical field of electronic glass manufacturing and glass testing equipment, and more specifically to the technical field of microcrystalline glass filament making equipment and method. Background Technology

[0002] Glass-ceramics are polycrystalline materials formed by controlling the crystallization process to precipitate a large number of tiny crystals within a glass matrix, possessing the dual properties of both glass and ceramics. With the rapid development of consumer electronics, automotive smart cockpits, and industrial display cover glass technologies, the market has placed extremely high demands on the mechanical properties of cover glass. Because of its controlled crystallization process that precipitates nanoscale crystals within a glass matrix, glass-ceramics achieve mechanical strength and drop resistance far exceeding that of ordinary glass, making it a core material for cover glass in high-end electronic devices.

[0003] In the research and development and performance testing phase of glass-ceramics, obtaining uniform, defect-free glass fibers that retain their original amorphous state is a prerequisite for testing key thermodynamic parameters such as viscosity curve determination, annealing point and strain point analysis, and softening point testing. However, the cooling process of the raw materials used in the preparation of glass-ceramics after melting is fundamentally different from that of traditional soda-lime glass or aluminosilicate glass. The formulation of glass-ceramics incorporates a large number of nucleating agents, giving it a strong tendency to crystallize within a specific temperature range (i.e., the crystallization temperature range).

[0004] In existing technologies, traditional glass fiber drawing equipment typically employs natural cooling or cooling in still air. When applied to glass-ceramics, the molten glass is prone to lingering in the crystallization temperature range for too long during the brief process of being drawn from the furnace and solidifying into a fiber, leading to premature and uncontrolled crystal precipitation. Once crystallization occurs, the uniformity, transparency, and flexibility of the glass fiber are compromised, making it brittle and uneven in internal structure, completely failing to meet the requirements of subsequent precision testing, and even causing the drawing process to fail due to breakage. Specifically, due to the special properties of glass-ceramics, there are insurmountable technical defects when using traditional fiber-making equipment to prepare glass-ceramic fibers, as follows: 1. High Difficulty in Crystallization Control: After the microcrystalline glass batch melts, it must pass through its inherent crystallization temperature range during the cooling and solidification process into filaments (the crystallization temperature range varies between different microcrystalline glass systems, such as 500℃~870℃ for LAS and 620℃~800℃ for MAS). Traditional filament-making equipment has a simple cooling system design, often using natural cooling or low-speed air cooling, which is insufficient. This causes the molten glass to remain within the crystallization temperature range for too long, easily leading to premature and uncontrollable crystal precipitation. This unintended crystallization directly results in the glass filament becoming brittle, losing its good flexibility and uniformity, and easily breaking during subsequent testing and processing, failing to meet usage requirements.

[0005] 2. Uncontrollable fiber-making parameters: Traditional fiber-making equipment is mostly operated manually or semi-manually, lacking precise parameter control mechanisms. Key parameters such as furnace heating rate, holding temperature, drawing speed, and cooling gas temperature and flow rate cannot be accurately set and stably controlled. The quality of glass fibers prepared by different batches and operators varies significantly, exhibiting problems such as uneven diameter, large length fluctuations, and poor performance consistency, failing to meet the needs of precision testing and mass production.

[0006] 3. Low fiber production efficiency and low success rate: Due to the inability to effectively solve the crystallization problem, the scrap rate is extremely high when traditional equipment is used to prepare microcrystalline glass fibers. At the same time, the manual operation process is cumbersome, the amount of fiber produced per batch is limited, and the equipment status needs to be adjusted frequently, resulting in low fiber production efficiency and failing to meet the needs of industrial mass production.

[0007] 4. Poor equipment adaptability: Traditional wire-making equipment is not specifically designed for the crystallization characteristics of glass-ceramics. The layout of its furnace structure, wire drawing mechanism, and cooling system is unreasonable. For example, the furnace opening design cannot achieve rapid opening and closing, resulting in excessive contact time between the molten glass and air, causing oxidation and crystallization. The positioning accuracy of the wire drawing mechanism is insufficient, resulting in excessive deviation in the diameter of the glass wire. The cooling gas cannot act evenly on the surface of the glass wire, resulting in uneven cooling, which further aggravates the problems of crystallization and uneven diameter.

[0008] 5. Lack of repeatability: Due to uncontrollable parameters and poor equipment stability, traditional wire-making processes cannot achieve repeated application of parameters. Even with the same glass raw materials, it is difficult to produce glass wires with consistent performance and size, which brings great inconvenience to subsequent testing and processing.

[0009] Currently, the industry lacks a dedicated wire drawing device specifically designed for the characteristics of glass-ceramics. This device must be able to precisely control the cooling rate of the molten glass during the forming process, ensuring it "passes" through the dangerous crystallization temperature zone at extremely high instantaneous speed, thereby completely suppressing the formation and growth of crystal nuclei and obtaining pure amorphous glass fibers. Simultaneously, the device should also possess controllable parameters and high repeatability to support the large-scale, standardized fiber production needs in research and manufacturing. Summary of the Invention

[0010] The purpose of this invention is to provide a microcrystalline glass filament making device and method in order to solve the above-mentioned technical problems.

[0011] To achieve the above objectives, the present invention specifically adopts the following technical solution: One aspect of the present invention provides a microcrystalline glass filament making device, including a high-temperature furnace, a positioning refractory platform, a crucible, a furnace top blind plate, a filament making chamber, a clamping platform, a drawing rod, a lifting rod, and a positioning and correction mechanism; The top of the high-temperature furnace has a furnace opening, and a furnace top blind plate is movably installed on the top of the high-temperature furnace to close or open the furnace opening; a positioning refractory platform is set inside the high-temperature furnace for the crucible and to align the opening of the crucible with the furnace opening; The wire-making chamber is sealed at the top of the high-temperature furnace. The bottom of the high-temperature furnace is provided with a wire-drawing through hole that communicates with the furnace opening. The bottom of the side wall of the wire-making chamber is provided with an air inlet, and the top of the side wall of the wire-making chamber is provided with an air outlet that communicates with the outside. The clamping platform is slidably set inside the yarn-making chamber through a positioning and correction mechanism. The lifting screw is vertically set inside the yarn-making chamber. The lower end of the lifting screw is fixedly connected to the clamping platform, and the upper end of the lifting screw extends out of the top of the yarn-making chamber through a sliding seal and is connected to the drive motor. The top of the drawing rod is clamped at the bottom of the clamping platform, and the lower end of the drawing rod is aligned with the drawing through hole.

[0012] In one embodiment, the front of the spinning chamber is provided with an openable and closable spinning glass door.

[0013] In one embodiment, the positioning and correction mechanism includes a positioning slide rod vertically fixed inside the yarn-making chamber, a clamping platform slidably mounted on the positioning slide rod inside the yarn-making chamber, and a three-jaw clamp for gripping the yarn-drawing rod on the clamping platform. The three-jaw clamp is made of stainless steel and has a clamping range of 5~10mm. A sliding bearing is provided between the clamping platform and the positioning slide rod to ensure smooth movement of the clamping platform and a positioning accuracy error of no more than 0.1mm.

[0014] In one embodiment, the wire drawing rod is a corundum rod, which is made of high-purity α-corundum material, with a diameter of 6~8mm and a length of 800~1000mm. The lower end of the corundum rod is conical with a cone tip angle of 30~45°.

[0015] In one embodiment, the air inlet is connected to a gas generator. The number of air inlets is 2 to 4, which are evenly distributed around the bottom of the side wall of the yarn forming chamber. The diameter of the air inlets is 8 to 12 mm. The air inlets are equipped with a flow regulating valve and a temperature controller. The flow regulating range is 20 to 100 cm³ / min, and the temperature control range is 50 to 200 °C. The diameter of the air outlet is 15~20mm, and a dustproof net is installed on the air outlet. The dustproof net is made of stainless steel wire and the aperture is 0.5~1mm.

[0016] In one embodiment, the furnace top blind plate is made of high-temperature resistant ceramic material, the diameter of the furnace top blind plate is larger than the diameter of the furnace hole, a graphite sealing gasket is provided between the furnace top blind plate and the positioning refractory platform, and a handle for easy pushing and pulling is provided on the furnace top blind plate. The silk-making chamber is made of stainless steel, with a height of 800~1000mm and an inner diameter of 300~400mm. The silk-making glass door is made of high-temperature resistant borosilicate glass, and a sealing strip is installed between the glass door and the silk-making chamber.

[0017] The positioning refractory platform is made of high-alumina refractory material, with a through hole diameter of 50~80mm and a thickness of 30~50mm. The positioning refractory platform is sealed with refractory adhesive between itself and the high-temperature furnace. The crucible is made of quartz glass, with a capacity of 500-1000mL, a wall thickness of 5-8mm, a height of 150-200mm, and an arc-shaped bottom. The positioning slide rod is made of stainless steel, with a diameter of 10~15mm and a length of 700~900mm. The positioning slide rod is fixed to the top of the yarn making chamber by welding, and a guide groove is provided on the positioning slide rod. The lifting screw has a precision grade of C7, and the lifting speed adjustment range is 0.1~1.0m / s. The external motor is a servo motor with a speed adjustment accuracy of 1r / min.

[0018] Another aspect of the present invention provides a method for drawing microcrystalline glass fibers, based on the above-described microcrystalline glass fiber-making equipment, comprising the following steps: S1: Equipment initialization: Check the equipment status and ensure that the furnace hole of the positioning refractory platform is aligned with the wire drawing through hole above the high-temperature furnace; check the equipment level and the clamping platform level; clamp the corundum rod on the clamping platform; control the lifting screw to descend so that the corundum rod passes through the wire drawing through hole above the high-temperature furnace for positioning, and then rise to the initial position; S2: Loading and Melting: Place the microcrystalline glass raw material in the crucible and push it into the furnace top blind plate to close the wire drawing through hole above the high-temperature furnace; heat the high-temperature furnace to temperature T1 to completely melt the glass, where T1 is greater than the upper limit temperature for crystallization of microcrystalline glass; at the same time, open the gas inlet and introduce gas at temperature T2, controlling the flow rate to V1 to pre-cool the wire forming chamber; S3: Wire drawing: Pull out the furnace top blind plate and open the wire drawing through hole above the high-temperature furnace; control the lifting screw to lower the clamping platform so that the corundum rod is immersed in the glass melt; after holding for a few seconds, control the lifting screw to rise at a speed of V2 to pull out the glass wire; S4: Cooling and Collection: During the drawing process, cooling gas is continuously introduced to rapidly cool the glass wire; after the glass wire has cooled, the blind plate on the top of the furnace is pushed in to close the drawing through hole above the high-temperature furnace; the solidified glass wire is clamped off, the glass wire making door is opened, and the glass wire is taken out.

[0019] Specifically, due to the height limitation of the fiber-making chamber design, the length of the glass fiber produced with uniform thickness is 600~700mm.

[0020] In one embodiment, the temperature T2 of the cooling gas is between room temperature and 150°C.

[0021] In one embodiment, the flow rate V1 of the cooling gas is 20 cm³ / min to 80 cm³ / min.

[0022] In one embodiment, the lifting speed V2 of the wire drawing rod is 0.2 m / s-0.8 m / s.

[0023] The beneficial effects of this invention are as follows: 1. This invention effectively suppresses crystallization and ensures glass quality: By introducing forced convection cooling gas into a sealed wire-forming chamber, the hot glass wire drawn from the high-temperature furnace is instantly placed in a high-speed flowing, low-temperature environment. This forced heat exchange greatly increases the cooling rate of the glass wire through its crystallization temperature range, effectively preventing the formation and growth of crystal nuclei, thereby producing high-quality microcrystalline glass wire that is completely amorphous, colorless, transparent, and has a uniform structure.

[0024] 2. Adjustable process parameters, adaptable to various material systems: This invention provides specific parameter adjustment schemes for microcrystalline glass with different compositions (such as LAS-based, MAS-based, etc.). By synergistically controlling the furnace temperature, cooling gas temperature, gas flow rate, and drawing speed, the diameter (stable between Φ0.5mm and Φ2.0mm) and quality of the glass wire can be precisely controlled, breaking through the limitations of traditional equipment that can only produce wires for a single material or a single specification.

[0025] 3. High repeatability and high fiber production efficiency: This invention transforms the experience-based manual fiber drawing operation into a standardized and mechanized process. By precisely controlling the lifting speed, immersion depth, and dwell time of the drawing rod, combined with a stable gas cooling environment, the consistency of results is ensured in multiple fiber production processes using the same material. This significantly improves the success rate and efficiency of fiber production, providing a reliable source of samples for subsequent scientific research testing or small-batch production.

[0026] 4. Compact structure and convenient operation: This invention integrates the yarn-making chamber and lifting mechanism into a single design, resulting in a reasonable layout and small footprint. The glass door facilitates observation and operation, while the positioning slide rod design ensures the verticality of the yarn drawing. The overall equipment is simple to operate and easy to maintain. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained from these drawings without creative effort.

[0028] Figure 1 This is a three-dimensional structural schematic diagram of the microcrystalline glass filament fabrication equipment of the present invention.

[0029] Figure 2 This is a front view of the microcrystalline glass filament making equipment of the present invention.

[0030] Figure 3 This is a top view of the microcrystalline glass filament making equipment of the present invention.

[0031] Figure 4 This is a cross-sectional view of the microcrystalline glass filament fabrication equipment of the present invention.

[0032] Figure 5 This is a temperature rise curve of the high-temperature furnace in Embodiment 1 of the present invention.

[0033] Figure 6 This is a temperature rise curve of the high-temperature furnace in Embodiment 2 of the present invention.

[0034] Attached reference numerals: 1. High-temperature furnace; 2. Positioning refractory platform; 3. Crucible; 4. Blind plate on furnace top; 5. Wire-making chamber; 6. Air inlet; 7. Wire-making glass door; 8. Clamping platform; 9. Wire drawing rod; 10. Lifting screw; 11. Air outlet; 12. Positioning slide rod. Detailed Implementation

[0035] To make the technical problems, technical solutions, and technical effects of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0037] It should be noted that similar reference numerals and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0038] In the description of the embodiments of the present invention, it should be noted that the terms "inner", "outer", "upper", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0039] One aspect of the present invention provides a microcrystalline glass filament making device, including a high-temperature furnace 1, a positioning refractory platform 2, a crucible 3, a furnace top blind plate 4, a filament making chamber 5, a clamping platform 8, a wire drawing rod 9, a lifting screw 10, and a positioning and correction mechanism. The top of the high-temperature furnace 1 has a furnace hole, and the furnace top blind plate 4 is movably installed on the top of the high-temperature furnace 1 to close or open the furnace hole; the positioning refractory platform 2 is installed inside the high-temperature furnace 1 for the crucible 3 and to make the opening of the crucible 3 opposite to the furnace hole; The wire-making chamber 5 is sealed at the top of the high-temperature furnace 1. The bottom of the high-temperature furnace 1 is provided with a wire-drawing through hole that communicates with the furnace hole. The bottom of the side wall of the wire-making chamber 5 is provided with an air inlet 6, and the top of the side wall of the wire-making chamber 5 is provided with an air outlet 11 that communicates with the outside. The clamping platform 8 is slidably set inside the yarn making chamber 5 through the positioning and correction mechanism. The lifting screw 10 is vertically set inside the yarn making chamber 5. The lower end of the lifting screw 10 is fixedly connected to the clamping platform 8. The upper end of the lifting screw 10 extends out of the top of the yarn making chamber 5 through a sliding seal and is connected to the drive motor. The top of the wire drawing rod 9 is clamped at the bottom of the clamping platform 8, and the lower end of the wire drawing rod 9 is aligned with the wire drawing through hole.

[0040] In one embodiment, the front of the silk-making chamber 5 is provided with an openable and closable silk-making glass door 7.

[0041] In one embodiment, the positioning and correction mechanism includes a positioning slide rod 12 vertically fixed inside the yarn-making chamber 5, a clamping platform 8 slidably mounted on the positioning slide rod 12 inside the yarn-making chamber 5, and a three-jaw clamp for gripping the yarn-drawing rod 9 on the clamping platform 8. The three-jaw clamp is made of stainless steel and has a clamping range of 5~10mm. A sliding bearing is provided between the clamping platform 8 and the positioning slide rod 12 to ensure smooth movement of the clamping platform 8 and a positioning accuracy error of no more than 0.1mm.

[0042] In one embodiment, the wire drawing rod 9 is a corundum rod, which is made of high-purity α-corundum material, with a diameter of 6~8mm and a length of 800~1000mm. The lower end of the corundum rod is conical, with a cone tip angle of 30~45°.

[0043] In one embodiment, the air inlet 6 is connected to an external gas generator. The number of air inlets 6 is 2 to 4, which are evenly distributed circumferentially on the bottom of the side wall of the yarn forming chamber 5. The diameter of the air inlet 6 is 8 to 12 mm. The air inlet 6 is equipped with a flow regulating valve and a temperature controller. The flow regulating range is 20 to 100 cm³ / min, and the temperature control range is 50 to 200 °C.

[0044] The diameter of the air outlet 11 is 15~20mm. A dustproof net is installed on the air outlet 11. The dustproof net is made of stainless steel wire and the aperture is 0.5~1mm.

[0045] In one embodiment, the furnace top blind plate 4 is made of high-temperature resistant ceramic material, the diameter of the furnace top blind plate 4 is larger than the diameter of the furnace hole, a graphite sealing gasket is provided between the furnace top blind plate 4 and the positioning refractory platform 2, and a handle for easy pushing and pulling is provided on the furnace top blind plate 4. The silk-making chamber 5 is made of stainless steel. The height of the silk-making chamber 5 is 800~1000mm and the inner diameter is 300~400mm. The silk-making glass door 7 is made of high-temperature resistant borosilicate glass. A sealing strip is installed between the glass door and the silk-making chamber 5.

[0046] The positioning refractory platform 2 is made of high-alumina refractory material, with a through hole diameter of 50~80mm and a thickness of 30~50mm. The positioning refractory platform 2 is sealed with refractory adhesive between itself and the high-temperature furnace 1. The crucible 3 is made of quartz glass. The capacity of the crucible 3 is 500~1000mL, the wall thickness of the crucible 3 is 5~8mm, the height of the crucible 3 is 150~200mm, and the bottom of the crucible 3 has an arc-shaped structure. The positioning slide rod 12 is made of stainless steel, with a diameter of 10~15mm and a length of 700~900mm. The positioning slide rod 12 is fixed to the top of the wire making chamber 5 by welding. The positioning slide rod 12 is provided with a guide groove. The lifting screw 10 has a precision grade of C7, a lifting speed adjustment range of 0.1~1.0m / s, and an external servo motor with a speed adjustment accuracy of 1r / min.

[0047] Another aspect of the present invention provides a method for drawing microcrystalline glass fibers, based on the above-described microcrystalline glass fiber-making equipment, comprising the following steps: S1: Equipment initialization: Check the equipment status and ensure that the furnace hole of the positioning refractory platform 2 is aligned with the wire drawing through hole above the high-temperature furnace 1; check the equipment level and the clamping platform 8 level; clamp the corundum rod on the clamping platform 8; control the lifting screw 10 to descend so that the corundum rod passes through the wire drawing through hole above the high-temperature furnace 1 for positioning, and then rises to the initial position. S2: Loading and melting: Place the microcrystalline glass raw material in the crucible 3, push in the furnace top blind plate 4 to close the wire drawing through hole above the high-temperature furnace 1; heat the high-temperature furnace 1 to temperature T1 to completely melt the glass, where T1 is greater than the upper limit temperature for crystallization of microcrystalline glass; at the same time, open the gas inlet 6 and introduce gas at temperature T2, control the flow rate to V1, and pre-cool the wire forming chamber 5; S3: Wire drawing: Pull out the furnace top blind plate 4 and open the wire drawing through hole above the high-temperature furnace 1; control the lifting screw 10 to lower the clamping platform 8 so that the corundum rod is immersed in the glass melt; after holding for a few seconds, control the lifting screw 10 to rise at a speed of V2 to pull out the glass wire; S4: Cooling and Collection: During the drawing process, cooling gas is continuously introduced to rapidly cool the glass wire; after the glass wire has cooled, the blind plate 4 on the top of the furnace is pushed in to close the drawing through hole above the high-temperature furnace 1; the solidified glass wire is clamped off, the glass wire making door 7 is opened, and the glass wire is taken out.

[0048] Specifically, due to the height limitation of the fiber-making chamber 5, the length of the glass fiber produced is 600~700mm, which is of uniform thickness.

[0049] In one embodiment, the temperature T2 of the cooling gas is from room temperature to 150°C.

[0050] In one embodiment, the flow rate V1 of the cooling gas is 20 cm³ / min to 80 cm³ / min.

[0051] In one embodiment, the lifting speed V2 of the wire drawing rod 9 is 0.2 m / s-0.8 m / s.

[0052] Example 1 This embodiment provides a method for fabricating lithium aluminum silicate (LAS) based microcrystalline glass, with the following specific requirements: Glass system: Lithium aluminum silicate (Li2O-Al2O3-SiO2) microcrystalline glass, with the following composition (mass fraction): Li2O 14.5%, Al2O3 8.5%, SiO2 70.0%, MgO 2.5%, ZnO 2.0%, TiO2 1.5%, ZrO2 1.0%. The main crystalline phase of this glass is β-spodumene solid solution (LiAlSi2O6), with a crystallization temperature range of 500℃~870℃.

[0053] Target product specifications: Glass fiber used for testing glass annealing point and strain point. Required length 445±2mm, diameter 0.55mm≤Φ≤0.75mm, diameter tolerance <0.04mm, no internal crystallization, colorless and transparent.

[0054] Equipment preparation: High-temperature furnace: maximum operating temperature 1200℃, temperature control accuracy ±1℃; Crucible: Platinum crucible, 1000 mL in volume; Corundum rod: 6mm in diameter, 400mm in length, 99.5% purity; Silk-making chamber: effective working height 1000mm, inner diameter 300mm; Gas generating device: Air compressor equipped with temperature control system, temperature control range 20℃~200℃.

[0055] Silk-making method steps: S1. Equipment Initialization Check: Ensure the positioning refractory platform is aligned with the center of the drawing hole above the high-temperature furnace. Use a level to check the overall level of the equipment and the level of the clamping platform, ensuring a levelness error of <0.5mm. Clamp the corundum rod onto the three-jaw clamp of the clamping platform, ensuring a secure clamping and good verticality. Start the lifting screw drive motor to control the clamping platform to descend, allowing the corundum rod to slowly pass through the drawing hole above the high-temperature furnace until the lower end of the corundum rod is approximately 20mm from the bottom of the crucible; record this position as the lower limit. Then control the clamping platform to rise to the highest position of the slide rod; record this position as the upper limit. Check that the lifting screw operates smoothly without any jamming.

[0056] S2. Charging and Melting: Weigh 500g of the microcrystalline glass batch material as described above and place it evenly in a platinum crucible. Place the crucible into the high-temperature furnace, push in the furnace top blind plate to completely close the wire drawing through hole above the high-temperature furnace, ensuring a good seal to reduce heat loss and external contamination. Start the high-temperature furnace heating program and operate according to the following table ( Figure 5 ):

[0057] At 120 minutes, the high-temperature furnace temperature reached and stabilized at 900℃ (approximately 30℃ above the upper limit of crystallization temperature of 870℃), and the glass was completely melted and clarified. At this point, the air inlet switch was opened, and the gas generator was started, introducing air at 120℃ at a flow rate controlled at 50 cm³ / min. The gas entered the wire-forming chamber through the inlet, pre-cooling the chamber, and then exited through the outlet, forming a stable airflow field. Pre-cooling continued for 5 minutes to allow the temperature field within the wire-forming chamber to stabilize.

[0058] S3. Wire Drawing: Slowly pull out the furnace top blind plate to open the wire drawing through-hole above the high-temperature furnace. At this time, the high-temperature molten glass is exposed to the wire-making chamber environment, but due to the continuously introduced cooling gas forming an air curtain, the heat loss from the high-temperature furnace and the violent influx of outside cold air are effectively reduced. Start the lifting screw to lower the clamping platform at a speed of 5 mm / s until the lower end of the corundum rod is immersed to a depth of about 15 mm below the surface of the molten glass. Hold it still for 5 seconds to allow the corundum rod to be fully heated and well wetted with the molten glass. Then, raise the clamping platform at a constant speed of 0.3 m / s, pulling the corundum rod out of the molten glass and taking the molten glass with it to form a glass wire. During the wire drawing process, air at 120°C is continuously introduced at a flow rate of 50 cm³ / min, allowing the glass wire to fully contact the cooling gas during its ascent, achieving rapid cooling.

[0059] S4. Cooling and Collection: When the clamping platform rises to near its upper limit, the glass wire has completely solidified. Push in the furnace top blind plate to close the wire drawing through-hole above the high-temperature furnace, clamping the glass wire. At this time, the upper end of the glass wire is still suspended on the corundum rod. Wait approximately 30 seconds to ensure the glass wire has fully cooled to room temperature. Open the wire-making glass door, clamp the glass wire approximately 20mm below the corundum rod clamp, and remove the glass wire. Use a micrometer to measure the diameter of the glass wire, and use a ruler to measure and cut the length.

[0060] Fiber production results: The obtained glass fiber was colorless and transparent, without any milky opacity, bubbles, or surface defects. The length was 700mm (limited by the height of the fiber-making chamber), with 445mm used for testing. The diameter measurement was 0.57±0.02mm (measured at 5 different locations: 0.56mm, 0.58mm, 0.57mm, 0.57mm, 0.59mm), meeting the requirements of 0.55mm≤Φ≤0.75mm and tolerance<0.04mm. XRD analysis of the glass fiber showed typical amorphous diffuse peaks with no crystalline diffraction peaks, proving the absence of internal crystallization. DSC analysis showed exothermic peaks in the temperature range of 500℃~870℃, indicating significant crystallization during the testing process, further confirming the absence of crystallization during fiber production.

[0061] Process parameter optimization experiment: To verify the influence of process parameters on the quality of glass fiber, multiple sets of comparative experiments were conducted, and the results are shown in the table below:

[0062] As shown in the table, under the same process parameters, the glass wire quality is stable with minimal diameter fluctuation (±0.02 mm). When the drawing speed increases from 0.30 m / s to 0.35 m / s, the glass wire diameter increases from approximately 0.57 mm to approximately 0.60 mm, indicating that the glass wire diameter can be precisely controlled by adjusting the drawing speed. No crystallization was observed in any of the experimental groups, proving the effectiveness of the method of this invention.

[0063] Example 2 This embodiment provides a method for fabricating magnesium aluminosilicate (MAS) based microcrystalline glass fibers, as follows: Glass system: Magnesium aluminum silicate (MgO-Al2O3-SiO2) microcrystalline glass, with the following composition (mass fraction): MgO 15.0%, Al2O3 5.0%, SiO2 75.0%, TiO2 3.0%, ZrO2 2.0%. The main crystalline phase of this glass is cordierite (Mg2Al4Si5O). 18 The crystallization temperature range is 620℃~800℃.

[0064] Target product specifications: Glass fiber used for glass softening point testing, requiring a length of 235±2mm, a diameter of 0.55mm≤Φ≤0.75mm, a diameter tolerance of <0.04mm, and internal crystallization-free, colorless and transparent.

[0065] Equipment preparation: The equipment configuration is the same as in Example 1, with an effective working height of 1000mm in the yarn-making chamber.

[0066] Silk-making steps: S1. Device initialization is the same as in Example 1.

[0067] S2. Charging and Melting: Weigh 500g of the above MAS-based microcrystalline glass batch material and place it in a platinum crucible. Place the crucible into the high-temperature furnace and push in the blind flange at the top of the furnace to close the opening. Start the heating program and operate according to the following temperature rise table ( Figure 6 ):

[0068] At 180 minutes, the high-temperature furnace temperature stabilized at 840℃ (approximately 40℃ above the upper limit of crystallization temperature, 800℃). The air inlet was opened, and air at 80℃ was introduced at a flow rate controlled at 40 cm³ / min. Pre-cooling was performed for 5 minutes to stabilize the temperature field in the fiber-forming chamber.

[0069] S3. Wire Drawing: Pull out the blind plate on the furnace top and open the wire drawing through hole above the high-temperature furnace. Control the lifting screw to descend at a speed of 5 mm / s, immersing the corundum rod to a depth of approximately 20 mm below the surface of the molten glass, and hold it still for 8 seconds. Then, raise the clamping platform at a constant speed of 0.5 m / s to draw out the glass wire. During the wire drawing process, continuously introduce air at 80°C, maintaining a flow rate of 40 cm³ / min.

[0070] S4. Cooling and collection: Same as in Example 1.

[0071] Fiber production results: The obtained glass fiber was colorless and transparent, without defects. The length was 700mm, of which 235mm was used for testing. The diameter measurements were 0.70±0.02mm (measured values: 0.69mm, 0.71mm, 0.70mm, 0.70mm, 0.72mm), meeting the requirements. XRD and DSC tests confirmed the absence of crystallization.

[0072] Study on the effect of temperature on the quality of glass fiber: To investigate the effect of furnace temperature on the quality of MAS-based microcrystalline glass fiber, a comparative experiment was conducted at a higher temperature. At 230 min, the high-temperature furnace temperature was increased from 840℃ to 900℃, while other parameters remained unchanged (air temperature 80℃, air velocity 40 cm³ / min, and rising speed 0.5 m / s).

[0073] The results showed that the diameter of the glass wire prepared at 900℃ was 0.60±0.02mm, which was smaller than the 0.70mm prepared at 840℃. This is because the viscosity of the molten glass decreases with increasing temperature, resulting in a smaller glass wire diameter at the same drawing speed. All samples showed no crystallization and had good appearance quality. The summarized data are shown in the table below.

[0074]

[0075] Example 3 The effect of different cooling gas conditions on the fabrication of LAS-based glass-ceramics.

[0076] To verify the key role of cooling gas parameters in suppressing crystallization, a comparative experiment with different gas temperatures and flow rates was designed based on Example 1.

[0077] Experimental design: With a fixed furnace temperature of 900℃ and an upward flow rate of 0.3 m / s, the air temperature and flow rate were varied, and the changes in the mass of the glass fiber were observed. The experimental results are shown in the table below:

[0078] Results analysis: Experimental group A1 (parameters of Example 1): Best results, no crystallization; Experimental group A2: Increasing the flow rate to 100 cm³ / min enhanced the cooling effect, slightly reduced the glass wire diameter (viscosity increased faster), and still did not crystallize. Experimental group A3: When the flow rate was reduced to 20 cm³ / min, insufficient cooling resulted in slight crystallization and emulsification. Experimental groups A4, A5, and A6: Crystallization-free wire fabrication can be achieved within a wide gas temperature range (25℃~200℃), indicating that the present invention has good process tolerance to gas temperature. Experimental group A7: No cooling gas was introduced, and the glass fibers relied on natural cooling from the environment. The glass fibers showed severe crystallization and obvious turbidity, which was completely unqualified.

[0079] This comparative experiment fully demonstrates the crucial role of flowing gas cooling in the present invention. When the cooling gas flow rate is below a certain threshold (approximately 30 cm³ / min), the cooling rate is insufficient and crystallization cannot be effectively suppressed; however, within a suitable flow rate range (50 cm³ / min to 200 cm³ / min), even with a wide variation in gas temperature, crystal-free glass fibers can be obtained.

[0080] Example 4 Control of glass wire diameter by different drawing speeds.

[0081] Based on Example 1, the effect of drawing speed on glass wire diameter was systematically studied to verify the feasibility of achieving precise diameter adjustment through speed control.

[0082] Experimental conditions: furnace temperature 900℃, air temperature 120℃, air velocity 50cm³ / min, wire drawing speed increased from 0.1m / s to 1.0m / s.

[0083] The experimental results are shown in the table below:

[0084] Results Analysis: As the drawing speed increases, the glass wire diameter shows a monotonically decreasing trend, consistent with the basic principle of viscosity drawing (diameter is inversely proportional to the square root of the speed). The highest diameter control accuracy (±0.02mm~±0.03mm) is achieved within the speed range of 0.3m / s to 0.5m / s, because the cooling and solidification process of the glass wire is most stable within this speed range. Even at higher speeds (1.0m / s), due to forced gas cooling, the glass wire can still maintain a non-crystallized state, with a diameter as small as 0.28mm, meeting the requirements for the preparation of micro-fine glass wires.

[0085] This embodiment demonstrates that the present invention can precisely control the glass wire diameter within a wide range (0.28mm~0.95mm) by simply adjusting the drawing speed, while maintaining the quality of no crystallization, and has excellent process flexibility and controllability.

[0086] Example 5 This embodiment describes the fabrication of easily oxidized microcrystalline glass fibers under nitrogen protection.

[0087] For components containing easily oxidizable components (such as Fe²⁺) + Ce³ + Microcrystalline glass (such as glass nanofibers) may undergo surface oxidation and discoloration during filamentation in air, affecting appearance quality and testing accuracy. This embodiment verifies the feasibility of using nitrogen as a cooling medium.

[0088] Glass system: LAS-based microcrystalline glass containing trace amounts of FeO (0.5wt%), which is easily oxidized in air and turns pale yellow.

[0089] Experimental conditions: furnace temperature 900℃, nitrogen temperature 120℃, nitrogen velocity 50cm³ / min, rising speed 0.3m / s.

[0090] Fiber production results: The obtained glass fiber was completely colorless and transparent, without any pale yellow staining, and its surface smoothness was superior to that of the air-cooled sample. The diameter was 0.58±0.02 mm, and XRD analysis showed no crystallization. Compared to the air-cooled control sample (slight staining), nitrogen protection effectively prevented surface oxidation, demonstrating that this invention can adapt to the fiber production requirements of microcrystalline glass with different properties by changing the type of cooling gas.

Claims

1. A microcrystalline glass filament making device, characterized in that, It includes a high-temperature furnace (1), a positioning refractory platform (2), a crucible (3), a furnace top blind plate (4), a wire-making chamber (5), a clamping platform (8), a wire-drawing rod (9), a lifting screw (10), and a positioning and correction mechanism; The high-temperature furnace (1) has a furnace hole on its top. The furnace top blind plate (4) is movably installed on the top of the high-temperature furnace (1) to close or open the furnace hole. The positioning refractory platform (2) is installed inside the high-temperature furnace (1) for the crucible (3) and to make the opening of the crucible (3) opposite to the furnace hole. The wire-making chamber (5) is sealed at the top of the high-temperature furnace (1). The bottom of the high-temperature furnace (1) is provided with a wire-drawing through hole that communicates with the furnace hole. The bottom of the side wall of the wire-making chamber (5) is provided with an air inlet (6). The top of the side wall of the wire-making chamber (5) is provided with an air outlet (11) that communicates with the outside. The clamping platform (8) is slidably disposed inside the yarn making chamber (5) through the positioning and correction mechanism. The lifting screw (10) is vertically disposed inside the yarn making chamber (5). The lower end of the lifting screw (10) is fixedly connected to the clamping platform (8). The upper end of the lifting screw (10) extends out of the top of the yarn making chamber (5) through a sliding seal and is connected to the drive motor. The top of the wire drawing rod (9) is clamped to the bottom of the clamping platform (8), and the lower end of the wire drawing rod (9) is aligned with the wire drawing through hole.

2. The microcrystalline glass filament making equipment according to claim 1, characterized in that, The front of the silk-making chamber (5) is provided with an openable and closable silk-making glass door (7).

3. The microcrystalline glass filament making equipment according to claim 1, characterized in that, The positioning and correction mechanism includes a positioning slide rod (12) that is vertically fixed inside the yarn making chamber (5). The clamping platform (8) is slidably sleeved on the positioning slide rod (12) inside the yarn making chamber (5). The clamping platform (8) is provided with a three-jaw clamp for gripping the yarn drawing rod (9). The clamping range of the three-jaw clamp is 5~10mm. A sliding bearing is provided between the clamping platform (8) and the positioning slide rod (12) to ensure that the clamping platform (8) moves smoothly and the positioning accuracy error does not exceed 0.1mm.

4. The microcrystalline glass filament making equipment according to claim 1, characterized in that, The wire drawing rod (9) is a corundum rod, which is made of high-purity α-corundum material, with a diameter of 6~8mm and a length of 800~1000mm. The lower end of the corundum rod is conical, with a cone tip angle of 30~45°.

5. The microcrystalline glass filament making equipment according to claim 1, characterized in that, The air inlet (6) is connected to a gas generating device. There are 2 to 4 air inlets (6) that are evenly distributed around the bottom of the side wall of the yarn making chamber (5). The diameter of the air inlet (6) is 8 to 12 mm. The air inlet (6) is equipped with a flow regulating valve and a temperature controller. The flow regulating range is 20 to 100 cm³ / min, and the temperature control range is 50 to 200 °C. The diameter of the air outlet (11) is 15~20mm. A dustproof net is provided on the air outlet (11). The dustproof net is woven from stainless steel wire and has a hole diameter of 0.5~1mm.

6. The microcrystalline glass filament making equipment according to claim 1, characterized in that, The furnace top blind plate (4) is made of high temperature resistant ceramic material. The diameter of the furnace top blind plate (4) is larger than the diameter of the furnace hole. A graphite sealing gasket is provided between the furnace top blind plate (4) and the positioning refractory platform (2). A handle for easy pushing and pulling is provided on the furnace top blind plate (4). The silk-making chamber (5) is made of stainless steel. The height of the silk-making chamber (5) is 800~1000mm and the inner diameter is 300~400mm. The silk-making glass door (7) is made of high-temperature resistant borosilicate glass. A sealing strip is provided between the glass door and the silk-making chamber (5).

7. A method for drawing microcrystalline glass fibers, based on the microcrystalline glass fiber-making equipment according to any one of claims 1 to 6, characterized in that, Includes the following steps: S1: Equipment initialization: Check the equipment status and ensure that the furnace hole of the positioning refractory platform (2) is aligned with the wire drawing through hole above the high-temperature furnace (1); check the equipment level and the clamping platform (8) level; clamp the corundum rod on the clamping platform (8); control the lifting screw (10) to descend so that the corundum rod passes through the wire drawing through hole above the high-temperature furnace (1) for positioning, and then rise to the initial position; S2: Loading and melting: Place the microcrystalline glass raw material in the crucible (3), push in the furnace top blind plate (4) to close the wire drawing through hole above the high temperature furnace (1); heat the high temperature furnace (1) to temperature T1 to completely melt the glass, where T1 is greater than the upper limit temperature of crystallization of microcrystalline glass; at the same time, open the air inlet (6) and introduce gas at temperature T2, control the flow rate to V1, and pre-cool the wire forming chamber (5); S3: Wire drawing: Pull out the furnace top blind plate (4), open the wire drawing through hole above the high temperature furnace (1); control the lifting screw (10) to lower the clamp platform (8) so that the corundum rod is immersed in the glass liquid; after holding for a few seconds, control the lifting screw (10) to rise at a speed of V2 to pull out the glass wire; S4: Cooling and collection: During the drawing process, cooling gas is continuously introduced to rapidly cool the glass wire; after the glass wire is cooled, push in the furnace top blind plate (4) to close the drawing through hole above the high temperature furnace (1); cut off the solidified glass wire, open the wire making glass door (7), and take out the glass wire.

8. The method for drawing microcrystalline glass according to claim 7, characterized in that, The temperature T2 of the cooling gas is between room temperature and 150°C.

9. The method for drawing microcrystalline glass according to claim 7, characterized in that, The flow rate V1 of the cooling gas is 20 cm³ / min to 80 cm³ / min.

10. The method for drawing microcrystalline glass according to claim 7, characterized in that, The lifting speed V2 of the wire drawing rod (9) is 0.2 m / s-0.8 m / s.

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