Extraction amount increasing overflow forming annealing device and design method thereof

Abstract

The invention discloses an extraction amount increasing overflow forming annealing device and a design method thereof, and belongs to the technical field of glass substrate manufacturing. A mature glass substrate overflow forming annealing device is selected as a design blue, geometric structure parameters, specific parameters and common parameters of the glass substrate overflow forming annealing device are obtained to serve as design references, and the length similarity relation of a thickness forming area and the similarity relation between the lengths of a pre-annealing area, a soaking area, an annealing area and a subsequent annealing area and heater power are established; and according to the established similarity relationship, obtaining the length parameter of the extraction amount lifting overflow forming annealing device, and completing the design of the glass substrate overflow forming annealing device. By adopting the design method, the problem that the cooling distance designed in the traditional theory is long is solved, more accurate, efficient and low-cost design of the overflow forming annealing device is realized, key forming quality indexes such as thickness, compression, stress and warping of the glass substrate are effectively guaranteed, and remarkable benefit improvement is brought to the glass substrate manufacturing industry.

Description

Technical Field

[0001] The invention relates to the technical field of glass substrate manufacturing, and in particular to an overflow molding annealing device with increased lead-out amount and a design method thereof. Background Art

[0002] In the manufacture of TFT-LCD (Thin Film Transistor Display) flat panel displays, the production of glass substrates occupies a core position, and its production process mainly relies on the advanced overflow down-draw method. This method precisely controls the delivery of molten glass from the glass melting furnace to a specific molten overflow down-draw molding device to form high-quality glass substrates.

[0003] In order to improve production efficiency and reduce overall manufacturing costs, the industry continues to explore innovative strategies. On the one hand, by increasing the lead-out volume, the production capacity is effectively expanded; on the other hand, through high-generation upgrades, a higher-generation overflow molding annealing device is designed to achieve wide-width, large-capacity and compatible production of glass substrates of various thicknesses. At the same time, this innovation is also committed to shortening the overall length of the production line, significantly reducing the vertical distance from the root of the overflow brick to the separation point of the substrate and the glass ribbon.

[0004] In the design process of overflow pull-down equipment, it is necessary to fully consider the increase in production capacity, the use of high strain point materials, the comprehensive manufacturing and the reduction of production line construction costs. In addition, it is also crucial to ensure the stability of the FDM process and the BOD cross-cutting process. However, with the increase in lead-out volume and the implementation of high-generation upgrades, the control of melting quality and molding quality has become the key to technical challenges, especially in the manufacture of LTPS / IGZO glass substrates, where thermal stability issues are particularly prominent.

[0005] The continuous gradual change of the physical properties of glass from the molten state to room temperature is the core of annealing theory. The quality of molding annealing directly affects the performance of the glass substrate. Traditional theory simplifies this process into a continuous change of "melt (viscosity)・viscoplastic body (viscoelasticity)・elastic body". However, the molding annealing device designed based on this theory often requires a longer cooling distance when using the uniform scale-up method, thereby increasing capital investment.

[0006] In order to achieve breakthroughs in large lead-out / thinning and LTPS / IGZO technology, more sophisticated cooling control of the molding part is necessary. Product quality can be improved by reducing the length of the molding target thickness area, widening the glass transition region (GTTR) and reducing compression. In terms of annealing design and process control, it is necessary to introduce cutting-edge theories, concepts and criteria, combine with updated annealing thermodynamic mechanisms, and comprehensively consider key factors such as glass substrate annealing design, molding annealing device length design, annealing cooling curve design, multiple sets of (short) roller force and warpage correlation design, and chimney effect and environmental pressure difference control.

[0007] The latest research results on the thermal history of glass show that glass will experience multiple glass states during the cooling process, including viscosity (free flow, high viscosity plasticity), viscoelasticity (elastic plasticity, initial state of elastic body, sub-rigid body) and elasticity (rigid body). In order to optimize the annealing process, different proportional rules need to be applied according to the characteristics of different glass states. By reducing the distance of the viscous zone through rapid cooling, extending the time of glass transition and annealing zone, and appropriately reducing the interval of the elastic zone, the physical shell of the molding device is kept unchanged while improving quality indicators such as stress and compression. Among them, in the viscous region, radiation dominates the cooling curve, and changes in cooling method or time have little effect on compression, so the fixed length can be maintained, and the thickness formation zone can be shortened by rapid cooling. In the viscoelastic region, compression, residual stress and shape are basically determined, and the length of this region is closely related to factors such as flow rate, viscosity and strain point. In the elastic region, as a non-value-added region, the temporary stress caused by uneven cooling should be minimized. It can be seen that the quality of molding annealing covers many aspects such as glass substrate annealing stress, thermal shrinkage, BOW shape and warping, thermal stability, etc. By introducing a comprehensive perspective of "temperature difference, structural difference, and thermal stress" to analyze the annealing mechanism of glass, we can provide a more comprehensive and in-depth theoretical basis for annealing theory.

[0008] Therefore, how to provide an overflow forming annealing device with increased lead-out amount and a design method thereof to overcome the misunderstandings in traditional theories has become a technical problem that current technicians in this field urgently need to overcome. Summary of the invention

[0009] The object of the present invention is to provide an overflow forming annealing device with improved lead-out amount and a design method thereof, so as to overcome the problem of too long cooling distance of the forming annealing device designed based on traditional theory in the prior art.

[0010] The present invention solves the above technical problems through the following technical solutions: A method for designing an overflow forming annealing device with increased lead-out amount comprises the following steps: Step 1: Select a mature glass substrate overflow forming annealing device as a reference forming annealing device, and obtain the geometric structure parameters, specific parameters and common parameters of the reference forming annealing device. The geometric structure parameters include the thickness forming area length of the reference device. , length of pre-annealing zone Length of the uniform heating zone , annealing zone length and the length of the subsequent annealing zone ; Specific parameters include the heating power of the pre-annealing zone heater , Heating power of the soaking zone heater , Heating power of annealing zone heater And the heating power of the subsequent annealing zone heater , lead-out amount , Overflow brick overflow surface width , Glass substrate specification width , Average side width of glass substrate And overflow brick slope height ; Common parameters include overflow brick slope half angle , density of glass substrate and the viscosity of the overflow brick root ; Step 2: Calculate the lead-out per unit length of the reference forming annealing device based on the parameters obtained in step 1 , Critical contraction width of the guide plate Width of guide plate ; Step 3: Calculate the thickness of the glass ribbon of the reference forming annealing device leaving the root of the overflow brick according to the parameters obtained in step 1 and the parameters calculated in step 2. And the guide speed ; Step 4: Lead out quantity according to unit length and the thickness of the glass strip leaving the root of the overflow brick , establish the length similarity relationship of the thickness formation zone; according to the obtained pre-annealing zone length Length of the uniform heating zone , annealing zone length , Length of subsequent annealing zone And the board speed , respectively establish the length similarity relationship of the pre-annealing zone, the soaking zone, the annealing zone and the subsequent annealing zone; according to the obtained heating power of the pre-annealing zone heater , Heating power of the soaking zone heater , Heating power of annealing zone heater And the heating power of the subsequent annealing zone heater , establish the similarity relationship of heating power of heaters in pre-annealing zone, soaking zone, annealing zone and subsequent annealing zone; Step 5. According to the length similarity relationship of the thickness forming zone, the length similarity relationship of the pre-annealing zone, the soaking zone, the annealing zone and the subsequent annealing zone, and the heating power similarity relationship of the heaters in the pre-annealing zone, the soaking zone, the annealing zone and the subsequent annealing zone, the design of the overflow forming annealing device with lead-out volume enhancement is completed.

[0011] Further, referring to the unit length lead-out amount of the forming annealing device According to the obtained output and overflow brick overflow surface width The calculation formula is: .

[0013] Further, referring to the critical shrinkage width of the guide plate of the forming annealing device is the overflow surface width of the overflow brick obtained and overflow brick slope height The calculation formula is: .

[0015] Further, referring to the lead plate width of the forming annealing device According to the obtained glass substrate specification width and average edge width of glass substrate The calculation formula is:

[0016] in, is the trimming factor for the edge panel, ; Average side width of glass substrate 150~175 mm.

[0017] Further, the thickness of the glass ribbon of the forming annealing device leaving the root of the overflow brick is is the half angle of the overflow brick slope obtained , density of glass substrate , Viscosity at the root of overflow brick And the lead-out per unit length The calculation formula is:

[0018] Where g is the acceleration due to gravity.

[0019] Further, referring to the guide plate speed of the forming annealing device The density of the glass substrate is obtained based on , Overflow brick overflow surface width , Glass substrate specification width , Width of guide plate and critical shrinkage width of the guide plate The calculation formula is:

[0020] in, It is the standard thickness of the glass substrate, i.e. the target molding thickness.

[0021] Furthermore, the length similarity relationship of the thickness forming zone is specifically:

[0022] in, To design the lead-out per unit length of the forming annealing device, specifically:

[0023] To design the thickness of the glass strip of the forming annealing device leaving the root of the overflow brick, the specific thickness is:

[0024] To design the thickness forming zone length of the forming annealing device, To design the lead-out amount of the forming annealing device, To design the overflow surface width of the overflow brick of the forming annealing device.

[0025] Furthermore, the length similarity relationship of the pre-annealing zone is specifically:

[0026] The similarity relationship of the length of the soaking zone is as follows:

[0027] The length similarity relationship of the annealing zone is specifically:

[0028] The length similarity relationship of the subsequent annealing zone is specifically:

[0029] in, To design the board drawing speed of the forming annealing device, specifically:

[0030] To design the lead plate width of the forming annealing device, specifically:

[0031] To design the glass substrate width of the forming annealing device, To design the average side plate width of the glass substrate of the forming annealing device, the average side plate width of the glass substrate of the forming annealing device is designed to be in the range of 150~175 mm; To design the critical shrinkage width of the guide plate of the forming annealing device, specifically:

[0032] To design the overflow slope height of the overflow brick; , , , The lengths of the pre-annealing zone, soaking zone, annealing zone and subsequent annealing zone of the forming annealing device are designed respectively. , , , They are the speed adjustment coefficients of the pre-annealing zone, soaking zone, annealing zone and subsequent annealing zone of the forming annealing device, where: , , , , Design guide plate width for designing forming annealing device.

[0033] Furthermore, the similarity relationship of the heating power of the pre-annealing zone heater is specifically as follows:

[0034] The similarity relationship of the heating power of the soaking zone heater is as follows:

[0035] The similarity relationship of the heating power of the heater in the annealing zone is specifically:

[0036] The similarity relationship of the heating power of the subsequent annealing zone heater is specifically:

[0037] in, , , , The heating powers of the heaters in the pre-annealing zone, soaking zone, annealing zone and subsequent annealing zone of the forming annealing device are designed respectively.

[0038] A lead-out amount-enhanced overflow forming annealing device is designed and manufactured based on the lead-out amount-enhanced overflow forming annealing device design method.

[0039] Compared with the prior art, the positive and progressive effects of the present invention are: The present invention provides a design method for an overflow molding annealing device with an increased lead-out amount, which not only considers the changes in the six physical property stages of glass during the cooling process, including free flow, high viscosity plasticity, elastic plasticity, initial state of elastic body, sub-rigid body to rigid body, strictly distinguishes irreversible structural difference from reversible structural difference, stress relaxation phenomenon in a narrow sense from stress relaxation phenomenon in a broad sense, but also fully considers the influence of two key annealing stages, namely, deformation prevention annealing and non-deformation annealing, as well as the four annealing states, namely, optimal, suboptimal, worst annealing state and subsequent annealing, and adopts a comprehensive analysis method of "temperature difference, structural difference, thermal stress" to deeply analyze the annealing mechanism of glass, thereby ensuring that the molding quality of glass during the annealing process, including thickness, compression, stress and warping, is accurately controlled. By rapidly cooling to reduce the distance of the viscosity zone, prolong the time of the vitrification and annealing zones, and appropriately reduce the interval of the elastic zone, the physical shell of the molding device is kept unchanged while improving quality indicators such as stress and compression.

[0040] Furthermore, the overflow molding annealing device provided by the present invention fully considers eight key links of overflow molding feeding, overflow, molding, warping, annealing, BOW shape, BOD and environmental airflow control. Based on advanced glass substrate relaxation theory, relaxation mechanism and annealing procedure, compared with the annealing device designed by the traditional uniform proportional amplification method, the overflow molding annealing device provided by the present invention can realize a more accurate, more efficient and lower-cost annealing process of overflow molding, which is particularly suitable for the refined design of large-lead-out, wide-plate, and thin glass substrate molding annealing devices, and can also meet the refined design requirements of LTPS / IGZO glass substrate molding annealing devices for performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings in the specification are used to provide further understanding of the present invention and constitute a part of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0042] Figure 1 It is a structural schematic diagram of the overflow molding system of the present invention; Figure 2 It is a schematic diagram of the structure of overflow-molded down-drawn glass of the present invention; Figure 3 It is a schematic diagram of the partial structure of overflow-molded down-drawn glass of the present invention; Figure 4 It is a schematic diagram of the design of the overflow forming annealing device of the present invention.

[0043] Among them, 1 is the overflow brick, 2 is the overflow trough, 3 is the glass liquid feeding device, 4 is the root of the overflow brick, 5 is the guide plate, 6 is the formed glass substrate, 7 is the pull-down direction of the glass substrate, For the glass substrate specification width, is the width of the glass substrate lead, is the overflow surface width of the overflow brick, is the critical shrinkage width of the guide plate, is the overflow surface slope height. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0045] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0047] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0048] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0049] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] The present invention is further described in detail below in conjunction with the accompanying drawings, which are intended to explain the present invention rather than to limit it.

[0051] See also Figure 1 The overflow molding system is composed of an overflow brick 1 and a glass liquid feeding device 3 connected to each other. An overflow trough 2 is provided in the overflow brick 1, and the bottom of the overflow brick 1 is an overflow brick root 4. When the glass substrate is manufactured in a molten overflow manner, the glass liquid melted by the glass melting furnace is supplied to the glass liquid feeding device 3 in the molten overflow molding device during the molding process, and overflows along the overflow trough 2 through both sides of the overflow brick 1 to form a glass substrate from below the overflow brick root 4.

[0052] When the glass melt is pushed from the proximal end to the distal end of the overflow trough 2, it is pushed by the mass force and pressure in the running direction, overcomes the laminar viscous resistance and flows downward from the overflow weir. The fluid dynamics equation based on this principle integrates the effects of the above forces and is the basis for the design of the overflow trough. On the vertical surface of the overflow, the mass force and pressure are large enough, and the viscosity is relatively low, the influence of the lateral surface tension is very small, and there is almost no lateral contraction; on the inclined surface, the mass force and pressure components along the inclined surface become significantly smaller, and the viscosity gradually increases, the effect of the lateral surface tension becomes prominent, and a significant lateral contraction occurs. Therefore, a platinum drain plate 5 is provided at the proximal and distal ends of the inclined surface of the overflow brick to partially resist the lateral contraction of the glass.

[0053] See also Figure 2 In the process of drawing down the glass substrate, the platinum guide plate 5 serves as the forming basis of the glass substrate, and the formed glass substrate 6 moves downward along the drawing down direction 7 of the glass substrate.

[0054] See also Figure 3 , in the figure is the specification width of the glass substrate, is the width of the glass substrate lead, is the overflow surface width of the overflow brick, is the critical contraction width of the guide plate, The height of the overflow surface slope. During the down-drawing of the glass substrate, the molten glass gradually forms a glass substrate along the glass guide plate; in the width direction, from the center of the glass substrate to the two ends of the glass substrate, the thickness of the glass substrate in the middle is thin and uniform, and the thickness of the glass substrate formed from the middle to the two sides becomes thicker and thicker. The target glass substrate specification width is generally the middle part with uniform thickness; the guide plate width Glass substrate removal specification width This is the thickness of the edge plate that needs to be removed.

[0055] See also Figure 4 The temperature range of the thickness forming zone in different functional sections of the forming annealing furnace device is The temperature range of the pre-annealing zone is The temperature range of the heat-saturation zone is The temperature range of the annealing zone is The temperature range of the subsequent annealing zone is ; The viscosity corresponding to different temperature ranges is: overflow brick tip temperature Set the corresponding viscosity , Theoretical annealing starting point temperature of glass substrate Set the corresponding viscosity , expansion softening point temperature Set the corresponding viscosity , Actual annealing starting point temperature Set the corresponding viscosity , strain point is the lower limit temperature of annealing Set the corresponding viscosity , Annealing furnace outlet temperature Corresponding viscosity ; Among them, the overflow brick tip temperature The corresponding viscosity , ; Annealing furnace outlet temperature , preferably, .

[0056] A method for designing an overflow forming annealing device for a glass substrate with improved lead-out amount comprises the following steps: Step 1: Select a mature glass substrate overflow forming annealing device as a design reference, and obtain the geometric structure parameters, specific parameters and common parameters of the design reference forming annealing device respectively. The geometric structure parameters include the thickness formation area length of the reference device , length of pre-annealing zone Length of the uniform heating zone , annealing zone length and the length of the subsequent annealing zone ; The specific parameters include the heating power of the pre-annealing zone heater , Heating power of the soaking zone heater , Heating power of annealing zone heater And the heating power of the subsequent annealing zone heater , lead-out amount , Overflow brick overflow surface width , Glass substrate specification width , Average side width of glass substrate And overflow brick slope height The common parameters include the overflow brick slope half angle , density of glass substrate and the viscosity of the overflow brick root ; Step 2: Calculate the lead-out per unit length of the reference forming annealing device based on the parameters obtained in step 1 , Critical contraction width of the guide plate Width of guide plate ; Step 3: Calculate the thickness of the glass ribbon of the reference forming annealing device leaving the root of the overflow brick according to the parameters obtained in step 1 and the parameters calculated in step 2. And the guide speed ; Step 4: Establish a similarity relationship between the length of the thickness forming zone according to the lead-out amount per unit length, the thickness of the glass ribbon leaving the root of the overflow brick and the target forming thickness; establish a similarity relationship between the lengths of the pre-annealing zone, soaking zone, annealing zone and subsequent annealing zone according to the lead-in speed; establish a similarity relationship between the heating powers of the heaters in the pre-annealing zone, soaking zone, annealing zone and subsequent annealing zone according to the heating powers of the heaters in the pre-annealing zone, soaking zone, annealing zone and subsequent annealing zone; Based on the above similarity relationship, the design of the glass substrate overflow molding annealing device is completed.

[0057] Furthermore, the formula for the lead-out amount per unit length of the forming annealing device is:

[0058]

[0059] in, To design the lead-out amount of the forming annealing device; is the lead-out amount of the reference forming annealing device; To design the overflow surface width of the overflow brick of the forming annealing device; The overflow surface width of the overflow brick of the reference forming annealing device; To design the lead-out per unit length of the forming annealing device; It is the lead-out amount per unit length of the reference forming annealing device.

[0060] Furthermore, the formula for the thickness of the glass ribbon of the forming annealing device leaving the root of the overflow brick is:

[0061]

[0062] in, To design the thickness of the glass strip leaving the root of the overflow brick in the forming annealing device; The thickness of the glass strip leaving the root of the overflow brick in the reference forming annealing device; is the half angle of the overflow slope of the overflow brick; is the density of the glass substrate; is the acceleration due to gravity; It is the viscosity at the root of the overflow brick.

[0063] Furthermore, the formula for designing the guide plate width is:

[0064]

[0065] in, , The guide plate widths of the design and reference forming annealing devices are respectively; , The average side plate width of the glass substrate of the designed and reference forming annealing devices, , ; is the trimming factor for the edge panel, ; , The specification widths of glass substrates for the designed and reference forming annealing devices are shown respectively.

[0066] Furthermore, the formula for the critical contraction width of the guide plate is:

[0067]

[0068] in, , The critical shrinkage width of the guide plate of the designed and reference forming annealing devices respectively; , The overflow slope heights of the design and reference overflow bricks respectively; , The overflow surface widths of the overflow bricks of the designed and reference forming annealing devices are shown respectively.

[0069] Furthermore, the formula for the board guide speed of the forming annealing device is:

[0070]

[0071] in, To design the board guide speed of the forming annealing device; The board guide speed of the reference forming annealing device; It is the standard thickness of the glass substrate (target molding thickness).

[0072] Specifically, the formula for the similarity relationship between the thickness forming zone length is:

[0073] in, To design the thickness forming zone length of the forming annealing device; The thickness of the forming zone is the length of the reference forming annealing device; is the target molding thickness.

[0074] Specifically, the formula for the similarity relationship of the lengths of the pre-annealing zone, the soaking zone, the annealing zone, and the subsequent annealing zone is:

[0075]

[0076]

[0077]

[0078] in, , , , The lengths of the pre-annealing zone, soaking zone, annealing zone and subsequent annealing zone of the forming annealing device are designed respectively; , , , are the lengths of the pre-annealing zone, soaking zone, annealing zone and subsequent annealing zone of the reference forming annealing device, respectively; , , , The speed adjustment coefficients of the lead plate in the pre-annealing zone, soaking zone, annealing zone and subsequent annealing zone of the forming annealing device are designed respectively. Preferably, , , , .

[0079] Specifically, the formula for the similarity relationship of the heating power of the pre-annealing zone, the soaking zone, the annealing zone and the subsequent annealing zone is:

[0080]

[0081]

[0082]

[0083] in, , , , The heating powers of the pre-annealing zone, soaking zone, annealing zone and subsequent annealing zone of the forming annealing device are designed respectively; , , , They are the heating powers of the pre-annealing zone, soaking zone, annealing zone and subsequent annealing zone of the reference forming annealing device respectively.

[0084] Specifically, according to the above similarity relationship, the total length of the glass substrate overflow molding annealing device is for: .

[0085] In the process of cooling glass from the molten state to room temperature, the continuous gradual change law of its physical properties is the only basis for annealing theory. However, the traditional theoretical framework of "melt (viscosity)・viscoplastic body (viscoelasticity)・elastic body" does not fully reveal the full picture of this complex process. According to research, glass will experience multiple different glass states during its cooling process, including viscous state (free flow, high viscosity plasticity), viscoelastic state (elastic plasticity, initial state of elastic body, sub-rigid body), and finally enter the elastic state (rigid body). Therefore, by introducing the comprehensive perspective of "temperature difference・structural difference・thermal stress" to analyze the annealing mechanism of glass, a more comprehensive and in-depth theoretical basis can be provided for annealing theory.

[0086] According to the new theoretical research results, the annealing of glass substrates is divided into six basic fluid characteristics: 1. Free-flowing melt stage, viscosity range: . Corresponding to the melt overflow zone of the melt overflow down-draw method: from melting, clarification, homogenization to the tip (root) of the overflow brick. Thermodynamic and kinetic characteristics: free flow, is the melt viscosity of the glass; It is close to the viscosity of the glass melt at the overflow brick tip.

[0087] 2. High viscosity plastic phase, viscosity range: . The thickness formation zone of the corresponding melt overflow pull-down method: from the tip (root) of the overflow brick through the thickness zone to the theoretical annealing point. Thermodynamic and kinetic characteristics: The displacement activity is large and the structural adjustment proceeds rapidly. It is the viscosity of the glass melt close to the overflow brick tip; is the starting viscosity of glass theoretical annealing, relaxation time Starts from 0 to (About a few seconds). Although there is a temperature difference, there is no structural difference, and there is no stress field in the glass.

[0088] 3. Elastic-plastic stage, viscosity range: (Beware of deformation annealing, the best annealing state). Corresponding to the pre-annealing zone of the melt overflow pull-down method: from the theoretical annealing point to the expansion softening point (deformation point). Thermodynamic and kinetic characteristics: structural group displacement and molecular displacement. The narrow sense of stress relaxation phenomenon is a typical feature of this stage. The structural adjustment reduces the structural difference. Plus the implicit structural difference Equal to the structural difference caused by the temperature difference , the revealed structural difference is 0, that is, complete stress dissipation effect.

[0089] 4. Initial stage of elastomer, viscosity range: (Beware of deformation annealing, suboptimal annealing state). Corresponding to the soaking (GTTR: glass transition) zone of the melt overflow pull-down method: from the expansion softening point (deformation point) to the actual annealing point. Thermodynamic and kinetic characteristics: The displacement of structural groups tends to molecular displacement. The sharp increase in viscosity causes a sharp decrease in displacement activity and differential deformation activity. Since the thermal conductivity decreases slightly with temperature drop, the temperature difference increases accordingly, even if the cooling rate remains unchanged, Approximately When the remaining structure is partially hidden, the proportion of thermal stress that has been revealed can be measured. The narrow stress relaxation phenomenon is eventually replaced by the broad stress relaxation phenomenon, and the internal stress is half hidden and half visible, that is, an incomplete stress dissipation effect.

[0090] 5. Transition to the fully elastic (sub-rigid) stage, viscosity range: (Non-deformation annealing, the worst annealing state). Corresponding to the stress control area of ​​the melt overflow pull-down method: the actual annealing upper limit to the theoretical annealing lower limit. Thermodynamic and kinetic characteristics: molecular displacement. Displacement and differential deformation tend to exhaust as the viscosity further increases. At this time , Although it has not yet reached the point where stress and strain are proportional and follow Hooke's law, it has already shown the characteristics of a sub-rigid body.

[0091] 6. Complete elastic body (rigid body) stage, viscosity range: (Subsequent annealing). Corresponding to the subsequent annealing zone of the melt overflow down-drawing method: Theoretical annealing lower limit is calculated by the actual annealing lower limit To below room temperature. Thermodynamic and kinetic characteristics: particle vibration. Viscosity is hour, , , that is, the generalized stress relaxation phenomenon disappears, and the stress is proportional to the strain and follows Hooke's law. The structural differences are fully revealed until the uniform room temperature, and no longer change, which is a permanent stress. The viscosity is greater than When the temperature difference is 0.040°C, the temperature difference only produces a reversible structural difference. Because there is no differential deformation, the structural difference is fully revealed. The thermal stress caused by this and disappearing with temperature uniformity is called temporary stress. Before the temporary stress disappears, it is superimposed with the permanent stress at the point where the vector coincides. When a single stress or superimposed stress exceeds the tensile strength of the glass, it will burst.

[0092] The annealing stage is to prevent deformation annealing ( ) and non-deformation annealing ( According to the annealing efficiency, it is divided into three annealing states, corresponding to the three physical property stages. is the theoretical annealing initial viscosity, is the actual annealing starting viscosity. Annealing stage ( ) Irreversible structural differences caused by temperature differences ( ) is related to viscosity, elapsed time and temperature difference; the structural difference reduced by structural adjustment ( ) is related to viscosity and elapsed time, but has nothing to do with the size of the temperature difference; the remaining structural difference ( ) is only related to viscosity, and has nothing to do with the elapsed time or the size of the temperature difference. The viscosity determines whether the remaining structural difference is partially or fully implied.

[0093] Revealed (measurable) structural differences (residual structural differences) ( ), the corresponding stresses include temperature difference stress (caused by temperature difference) and expansion difference stress (caused by expansion difference). The temperature difference produces viscosity difference, expansion difference and density difference, reflecting the irreversible structural difference caused by structural adjustment ( ) The corresponding stresses include temperature difference stress (caused by temperature difference) and expansion difference stress (caused by expansion difference). As the viscosity increases dramatically, the thermal conductivity decreases slightly with the temperature drop, which increases the temperature difference stress accordingly. Even if the cooling rate remains unchanged, the irreversible structural difference increases instead of decreasing. The structural difference reduced by structural adjustment caused by structural groups or molecular displacement ( ) As the viscosity increases sharply, the displacement activity decreases sharply, which significantly reduces the structural difference. The structural difference implied (undetectable) by the differential deformation (residual structural difference) ( ) Unlike structural adjustment, it cannot reduce the structural difference at all, but is only a temporary implication. As the viscosity increases sharply, the differential deformation activity decreases sharply, which significantly reduces the structural difference.

[0094] The design method of the overflow molding annealing device for glass substrates provided by the present invention overcomes the misunderstanding of traditional theories, realizes a more accurate, more efficient and lower-cost overflow molding annealing device design, and ensures thickness, compression, stress, warping and other molding qualities. By reducing the distance of the viscous zone through rapid cooling, extending the time of the vitrification and annealing zones, and appropriately reducing the interval of the elastic zone, the physical shell of the molding device is kept unchanged while improving quality indicators such as stress and compression. Among them, in the viscous area, radiation dominates the cooling curve, and changes in the cooling method or time have little effect on compression, so a fixed length can be maintained, and the thickness formation zone can be shortened by rapid cooling. In the viscoelastic area, compression, residual stress and shape are basically determined, and the length of this area is closely related to factors such as flow rate, viscosity and strain point. In the elastic area, as a non-value-added area, the temporary stress caused by uneven cooling should be minimized.

[0095] The present invention is further described in detail below with reference to the embodiments.

[0096] A method for designing an overflow forming annealing device with increased lead-out amount comprises the following steps: 1. Obtain the geometrical parameters of the overflow forming annealing device for mature glass substrates, including the length of the thickness forming zone , the length of the pre-annealing zone , length of the soaking zone , the length of the annealing zone and the length of the subsequent annealing zone ; Get specific parameters, including the amount of lead , Overflow brick overflow surface width , overflow brick slope height , Glass substrate specification width , Average side width of glass substrate , Heating power of pre-annealing zone heater , Heating power of the soaking zone heater , Heating power of annealing zone heater And the heating power of the subsequent annealing zone heater .

[0097] 2. Obtain the common parameters of the mature glass substrate overflow molding annealing device and the target design molding annealing device, including the overflow brick slope half angle , density of glass substrate , Viscosity at the root of overflow brick .

[0098] 3. Set the target design of the lead-out amount of the forming annealing device , Overflow brick overflow surface width , overflow brick slope height , Glass substrate specification width , Average side width of glass substrate And target molding thickness of glass substrate .

[0099] 4. Calculate the length of the thickness formation zone: The method for calculating the length of the thickness forming zone of the overflow forming annealing device comprises the following steps: L1 calculates the lead-out per unit length:

[0100]

[0101] L2 Calculate the thickness of the glass ribbon of the forming annealing device leaving the root of the overflow brick:

[0102]

[0103] in, is the acceleration due to gravity; L3 Calculate and design the thickness forming zone length of the forming annealing device :

[0104] 5. Calculate and design the length of each annealing zone of the forming annealing device: The method for calculating the length of each annealing zone of the overflow forming annealing device includes the following steps: S1 Calculate the width of the guide plate:

[0105]

[0106] in, , , .

[0107] S2 Calculate the critical shrinkage width of the drainage plate:

[0108]

[0109] S3 Calculate the board guide speed of the forming annealing device:

[0110]

[0111] S4 Calculate and design the length of each annealing zone of the forming annealing device , , , :

[0112]

[0113]

[0114]

[0115] in, , , , .

[0116] S5 Calculate and design the total length of the forming annealing device :

[0117] 6. Calculate and design the heating power of each annealing zone of the forming annealing device:

[0118]

[0119]

[0120]

[0121] The moving glass ribbon is from the temperature Cool to , its heat energy loss rate (unit: )for:

[0122] in, is the lead-out amount of the glass substrate; is the specific heat capacity of glass; ; Theoretical annealing starting point temperature of the glass substrate; Thickness formation area The temperature difference.

[0123] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A design method for an overflow forming annealing device with increased lead-out volume, characterized in that: The following steps are involved: Step 1: Select a mature glass substrate overflow forming annealing device as a reference forming annealing device, and obtain the geometric structure parameters, specific parameters and common parameters of the reference forming annealing device respectively. The geometric structure parameters include the thickness forming area length of the reference device. , length of pre-annealing zone Length of the uniform heating zone , annealing zone length and the length of the subsequent annealing zone ; The specific parameters include the heating power of the pre-annealing zone heater , Heating power of the soaking zone heater , Heating power of annealing zone heater And the heating power of the subsequent annealing zone heater , lead-out amount , Overflow brick overflow surface width , Glass substrate specification width , Average side width of glass substrate And overflow brick slope height The common parameters include the overflow brick slope half angle , density of glass substrate and the viscosity of the overflow brick root ; Step 2: Calculate the lead-out per unit length of the reference forming annealing device based on the parameters obtained in step 1 , Critical contraction width of the guide plate Width of guide plate ; Step 3: Calculate the thickness of the glass ribbon of the reference forming annealing device leaving the root of the overflow brick according to the parameters obtained in step 1 and the parameters calculated in step 2. And the guide speed ; Step 4: Lead out quantity according to unit length and the thickness of the glass strip leaving the root of the overflow brick , establish the length similarity relationship of the thickness formation zone; according to the obtained pre-annealing zone length Length of the uniform heating zone , annealing zone length , Length of subsequent annealing zone And the board speed , respectively establish the length similarity relationship of the pre-annealing zone, the soaking zone, the annealing zone and the subsequent annealing zone; according to the obtained heating power of the pre-annealing zone heater , Heating power of the soaking zone heater , Heating power of annealing zone heater And the heating power of the subsequent annealing zone heater , establish the similarity relationship of heating power of heaters in pre-annealing zone, soaking zone, annealing zone and subsequent annealing zone; Step 5. According to the length similarity relationship of the thickness forming zone, the length similarity relationship of the pre-annealing zone, the soaking zone, the annealing zone and the subsequent annealing zone, and the heating power similarity relationship of the heaters in the pre-annealing zone, the soaking zone, the annealing zone and the subsequent annealing zone, the design of the overflow forming annealing device with lead-out volume enhancement is completed.

2. The design method of an overflow forming annealing device with increased lead-out amount according to claim 1 is characterized in that: The lead-out amount per unit length of the reference forming annealing device According to the obtained output and overflow brick overflow surface width The calculation formula is: 。 3. The design method of an overflow forming annealing device with increased lead-out amount according to claim 2 is characterized in that: The critical shrinkage width of the guide plate of the reference forming annealing device is the overflow surface width of the overflow brick obtained and overflow brick slope height The calculation formula is: 。 4. The design method of an overflow forming annealing device with increased lead-out amount according to claim 3 is characterized in that: The guide plate width of the reference forming annealing device According to the obtained glass substrate specification width and average edge width of glass substrate The calculation formula is: in, is the trimming factor for the edge panel, ; Average side width of glass substrate It is 150~175mm.

5. The design method of an overflow forming annealing device with increased lead-out amount according to claim 4 is characterized in that: The thickness of the glass ribbon of the reference forming annealing device leaving the root of the overflow brick is the half angle of the overflow brick slope obtained , density of glass substrate , Viscosity at the root of overflow brick And the lead-out per unit length The calculation formula is: Where g is the acceleration due to gravity.

6. The method for designing an overflow forming annealing device with increased lead-out amount according to claim 5, characterized in that: The guide plate speed of the reference forming annealing device The density of the glass substrate is obtained based on , Overflow brick overflow surface width , Glass substrate specification width , Width of guide plate and critical shrinkage width of the guide plate The calculation formula is: in, It is the standard thickness of the glass substrate, i.e. the target molding thickness.

7. The design method of an overflow forming annealing device with increased lead-out amount according to claim 6, characterized in that: The length similarity relationship of the thickness forming region is specifically: in, To design the lead-out per unit length of the forming annealing device, specifically: To design the thickness of the glass strip of the forming annealing device leaving the root of the overflow brick, the specific thickness is: To design the thickness forming zone length of the forming annealing device, To design the lead-out amount of the forming annealing device, To design the overflow surface width of the overflow brick of the forming annealing device.

8. The method for designing an overflow forming annealing device with increased lead-out amount according to claim 7, characterized in that: The length similarity relationship of the pre-annealing zone is specifically: The similarity relationship of the length of the soaking zone is specifically: The length similarity relationship of the annealing zone is specifically: The length similarity relationship of the subsequent annealing zone is specifically: in, To design the board guide speed of the forming annealing device, specifically: To design the lead plate width of the forming annealing device, specifically: To design the glass substrate width of the forming annealing device, The average side plate width of the glass substrate of the designed forming annealing device is in the range of 150-175 mm; To design the critical shrinkage width of the guide plate of the forming annealing device, specifically: To design the overflow slope height of the overflow brick; , , , The lengths of the pre-annealing zone, soaking zone, annealing zone and subsequent annealing zone of the forming annealing device are designed respectively. , , , They are the speed adjustment coefficients of the pre-annealing zone, soaking zone, annealing zone and subsequent annealing zone of the forming annealing device, where: , , , , Design guide plate width for designing forming annealing device.

9. The design method of the overflow forming annealing device with increased lead-out amount according to claim 8 is characterized in that: The similarity relationship of the heating power of the pre-annealing zone heater is specifically: The similarity relationship of the heating power of the soaking zone heater is specifically: The similarity relationship of the heating power of the heater in the annealing zone is specifically as follows: The similarity relationship of the heating power of the subsequent annealing zone heater is specifically: in, , , , The heating powers of the heaters in the pre-annealing zone, soaking zone, annealing zone and subsequent annealing zone of the forming annealing device are designed respectively.

10. An overflow forming annealing device with increased lead-out amount, characterized in that: The invention is designed and manufactured based on the design method of an overflow forming annealing device with increased lead-out amount as described in any one of claims 1 to 9.

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