A building energy-saving glass molding equipment and method

Abstract

This invention discloses a molding equipment and method for building energy-saving glass. The method includes: in the heating stage, using model predictive control to dynamically adjust the heating power to minimize the temperature difference between the glass blank surface and core, and to ensure that it reaches the temperature corresponding to the target viscosity at a target time; in the pressurization stage, based on the initial contact pressure and flow velocity, the glass viscosity is inverted in real time, and the pressure is calculated and adjusted in real time by combining the mold flow resistance function that varies with the filling volume and the remaining filling time; in the cooling stage, based on the final pressure, temperature distribution, and viscoelastic model, the initial residual stress field is quickly calculated, and the safe cooling rate is dynamically determined according to the maximum tensile stress, product thickness, and shape complexity. The equipment includes a frame mold closing mechanism, a mold unit, a heating unit, a pressurization unit, a cooling unit, and a control unit.

Description

Technical Field

[0001] This invention relates to die-casting technology for energy-saving building glass, and more particularly to a molding equipment and method for energy-saving building glass. Background Technology

[0002] As an important component of modern green buildings, energy-efficient architectural glass not only needs to meet basic lighting and enclosure functions, but also increasingly seeks to achieve integrated performance such as light guiding, sun shading, and decoration through surface microstructures, textures, or special geometric shapes. Molding, which involves heating and softening the glass and then pressing it into a specific shape in a mold, is a key process.

[0003] The existing molding technology for energy-saving architectural glass has the following technical problems in actual production: In the heating and temperature control process, existing technologies suffer from significant deficiencies in uniformity and precision. Currently, equipment such as box furnaces and tunnel kilns are commonly used for heating, and their heating programs are mostly pre-set fixed curves.

[0004] It is difficult to respond to real-time thermal disturbances caused by uneven temperature field distribution in the furnace, differences in glass blank size or heat capacity during actual production. This results in a large temperature difference between the surface and core of the glass blank during the heating process, which not only induces internal thermal stress but also affects warping in subsequent processes or use, and may even cause it to crack due to thermal shock during the heating stage.

[0005] Furthermore, the inability to precisely heat the glass to the temperature corresponding to the target viscosity at a preset time point leads to inconsistent material states.

[0006] Secondly, during the pressure molding stage, existing processes are poorly adaptable to complex changes, making it difficult to guarantee filling quality. The viscosity of glass at the molding temperature is extremely sensitive to temperature, and the flow resistance within the mold cavity increases dynamically and dramatically with the filling process, especially when flowing through narrow textures or complex geometric features. The inability to adapt to these real-time changes in material rheological behavior and mold geometric resistance easily leads to defects such as incomplete mold cavity filling, distorted microstructure replication, damage to localized areas due to excessive extrusion, or the formation of bubbles due to insufficient pressure.

[0007] Finally, the cooling process after molding is crucial for eliminating residual stress inside the glass and preventing cracking. However, in existing processes, the cooling rate largely depends on the operator's experience, lacking rapid assessment and feedback of the transient stress state inside the glass after molding. This results in insufficient stress release when cooling is too fast, leading to potential cracking or insufficient strength; while too slow cooling severely slows down production and reduces efficiency. Summary of the Invention

[0008] To address the shortcomings of the existing technology, this invention proposes a molding equipment and method for energy-saving building glass.

[0009] The technical solution of this invention is implemented as follows: A method for molding energy-saving architectural glass, comprising: Heating stage: The glass preform placed in the mold is heated to the forming temperature range. During this process, the heating power is dynamically adjusted based on the model predictive control method to minimize the temperature difference between the surface and the core of the glass preform and to make it reach the temperature corresponding to the target viscosity at the target time. Pressurization stage: After reaching the molding temperature range, pressure is applied to the mold to form the glass. During this process, the current viscosity of the glass is inverted in real time based on the initial contact pressure and initial flow velocity. Based on the real-time viscosity, the mold flow resistance function that dynamically changes with the filling volume, and the remaining filling time, the applied pressure is calculated and adjusted in real time to control the complete filling of the mold cavity by the glass melt. Cooling stage: After the pressure holding is completed, based on the final pressure holding pressure, the three-dimensional temperature distribution inside the glass and the viscoelastic model, the initial residual stress field inside the glass product is quickly calculated, and the safe cooling rate is dynamically decided and executed according to the maximum tensile stress value in the initial residual stress field, the product thickness and shape complexity.

[0010] Preferably, in the heating stage, the model predictive control method includes: Minimize the accumulated temperature difference between the glass surface and the core from the start of heating to the target time, and constrain the endpoint temperature to precisely reach the temperature corresponding to the target viscosity; Preferably, the model predictive control method further includes: the heating rate not exceeding a preset maximum heating rate. The temperature difference between each heating zone and the average temperature does not exceed the preset temperature uniformity tolerance. .

[0011] Preferably, during the pressurization stage, the overall real-time viscosity is considered. Flow resistance function and remaining time By calculating the control pressure at the next moment.

[0012] Preferably, the flow resistance function For the already filled volume The mapping of values ​​changes dynamically with the filling process, quantitatively describing the flow resistance at various points within the mold cavity.

[0013] Preferably, during the cooling stage, the initial residual stress field is calculated based on the three-dimensional temperature distribution within the glass body and the viscoelastic behavior of the material itself. .

[0014] Preferably, before the heating step, a mold pretreatment step is included: cleaning the mold cavity and applying a release agent, preheating the mold to 600-800°C; and cleaning and drying the glass blank.

[0015] A molding equipment for energy-saving building glass, the molding equipment comprising: Frame and mold closing mechanism; Mold unit mounted on the frame and mold closing mechanism; A heating unit for heating the glass blank inside the mold unit; A pressurizing unit used to apply pressure to glass preforms; A cooling unit used to cool molded products; The control unit is electrically connected to the heating unit, pressurizing unit, and cooling unit, and the control unit includes: A model prediction control module is used to control the heating unit; An online rheological control module is used to control the pressurization unit; A stress-guided decision module is used to control the cooling unit.

[0016] The molding equipment and method for energy-saving building glass according to the present invention have the following beneficial effects: 1. Precise and uniform temperature control is achieved during the heating stage. Temperature data from each heating zone and the glass blank are collected in real time, and the heating power is continuously optimized over the future time domain based on a heat transfer model. This minimizes the temperature difference between the glass surface and the core, ensuring that the glass reaches the temperature corresponding to the target molding viscosity precisely within a preset time. This overcomes the thermal shock and temperature unevenness problems caused by traditional fixed-program heating.

[0017] 2. The current viscosity of the glass melt is inverted in real time using the contact pressure and flow velocity at the initial moment of pressurization. Combined with the mold flow resistance function that dynamically changes with the filling volume obtained through CFD simulation, the required pressure curve is calculated and adjusted in real time. When an increase in flow resistance is detected due to increased viscosity or narrowing of the flow channel, the pressure is increased proportionally to maintain the filling speed; conversely, the pressure is decreased.

[0018] 3. After the pressure holding period, an integrated fast finite element solver is used to quickly calculate the initial residual stress field inside the product, combining the final pressure, the three-dimensional temperature distribution within the glass, and a viscoelastic constitutive model. Then, based on the maximum tensile stress value in this stress field, and considering the product thickness and shape complexity, an optimal, differentiated safe cooling rate is dynamically determined. This ensures cooling efficiency while maximizing the safe release of internal stress, preventing product cracking or deformation due to improper cooling. Attached Figure Description

[0019] Figure 1 This is a flowchart of the building energy-saving glass molding method of the present invention; Figure 2 This is a flowchart of the building energy-saving glass molding method of the present invention; Figure 3 This is a structural block diagram of the energy-saving glass molding equipment for buildings according to the present invention; The reference numerals in the attached figures are as follows: 10-frame and mold closing mechanism, 20-mold unit, 30-heating unit, 40-pressurizing unit, 50-cooling unit, 60-control unit, 601-model prediction control module, 602-online rheological control module, 603-stress-oriented decision module, and 604-input module. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0021] The process involves heating base glass to its softening point, injecting it into a mold, and applying pressure within the mold to shape it into a specific form and texture. It is generally used in the production of architectural decorative glass, energy-saving glass, and recessed lens glass with embossed, patterned, textured, or special geometric shapes.

[0022] The glass is heated to its softening point using a box furnace, tunnel kiln, or specialized molding press with heating plates that allows for precise temperature control. The mold typically consists of an upper mold and a lower mold, one of which is a punch and the other a die. The materials used for the upper and lower molds must be heat-resistant, oxidation-resistant, and have a low coefficient of thermal expansion. High-grade alloy steel (such as H13), graphite, or ceramic are commonly used.

[0023] Pressure is applied to a mold using a molding press with controllable hydraulic or servo mechanical pressure, typically ranging from several megapascals to tens of megapascals.

[0024] In this embodiment, the base glass is typically float glass, flat glass, or glass blocks / granules with specific compositions. The glass must have good chemical stability, a coefficient of thermal expansion matching the mold material, and meet building safety standards. To prevent the glass from sticking to the mold at high temperatures, graphite-based, boron nitride (BN), or high-temperature resistant metal oxide coatings are commonly used as release agents.

[0025] Example 1 Reference Figures 1 to 2 As shown in the figure, this embodiment proposes a molding method for building energy-saving glass, the specific steps of which include: Step 1: Clean the mold cavity to ensure there are no contaminants, and apply the release agent evenly to the molding surface; preheat the mold to near the glass forming temperature, usually 600-800°C, to reduce thermal shock and ensure uniform temperature; then cut the flat glass into glass blanks slightly larger than the finished product size; thoroughly clean and dry to remove surface oil and impurities.

[0026] Step 2: Place the clean glass blank into the preheated mold cavity; after mold closing, perform the second stage of heating, heating the glass blank at a controllable rate to the glass forming temperature range, reducing the glass viscosity to a suitable range for plastic forming. The controllable rate is generally 5-15°C / min; for soda-lime-silica glass, the forming temperature range is 700-850°C; the suitable range for plastic forming is 10^4 - 10^7 dPa·s.

[0027] Once the preset molding temperature is reached, the molding machine is started. The pressure, pressurization speed, and holding time of 5-20 MPa are set to apply pressure to the mold, causing the softened glass to completely fill the mold cavity and imprint the texture and shape of the mold. During the holding process, it helps the glass micro-flow and structural relaxation, ensuring shape stability and reducing defects.

[0028] Step 3: After forming, temperature-controlled cooling is performed under pressure holding or slight decompression. First, the glass is passed through the annealing point at a slower rate to eliminate the main thermal stress; then, cooling can be accelerated to room temperature. This process must be carried out precisely in an annealing furnace to prevent cracking or stress concentration.

[0029] After cooling to a safe temperature, the mold is opened, and the product is removed. Excess material is cleaned from the edges of the product, and edge grinding is performed if necessary. To meet building safety regulations, molded glass often requires tempering or heat strengthening. This process is carried out in a specialized tempering furnace, where the glass is reheated and then rapidly cooled to form a surface compressive stress layer. It should be noted that tempering may cause slight shape changes, and compensation should be considered in the mold design.

[0030] Finally, quality inspection is carried out, using calipers, 3D scanning or templates to check the product dimensions, curvature and pattern depth; checking for defects such as bubbles, stones, streaks, pits, mold marks, etc. under standard light sources; and using a polarizing stress meter to check the surface stress value and distribution uniformity after annealing or tempering.

[0031] After final cleaning and drying, qualified products are protected by materials such as release paper, corner protectors, and special wooden boxes, depending on their characteristics.

[0032] Furthermore, excessively low temperatures lead to incomplete filling and increased pressure requirements; excessively high temperatures can cause glass crystallization, mold sticking, and surface quality deterioration. Through precisely controlled heating, pressurizing, and cooling processes, flat glass or glass stock is formed within a mold into architectural glass products with predetermined three-dimensional shapes, surface textures, or optical functional structures. Specifically, this includes the following steps: Step 201: Establish a viscoelastic model of glass to describe the relationship between stress, strain, and time. The specific formulas are as follows: ; In the formula, This represents the stress experienced by the material at time t. This represents the strain experienced by the material at time t; The relaxation time is the time required for the stress of the i-th molecular or structural unit inside the material to decay to 1 / e of its initial value when it responds to an external force. It represents the equilibrium modulus, which is the proportional relationship between strain after complete relaxation and stress. Indicates viscosity.

[0033] The complex behavior of glass at forming temperatures was quantified. The relationship between applied stress (pressure), strain (deformation of the glass), and deformation rate was established. Using this viscoelastic model, the shape evolution of glass under different pressures was predicted through pre-simulation.

[0034] In the viscoelastic model of glass, viscosity It is not constant; it depends on the actual temperature T of the glass material, expressed as: ; In the formula, T represents the viscosity of glass at temperature T; A represents the pre-exponential factor, a constant related to the viscosity limit of glass at infinitely high temperatures, reflecting the entropy change characteristics of the material; B represents the activation energy parameter, reflecting the sensitivity of viscosity to temperature, with a larger B value indicating a more drastic change in viscosity with temperature; T0 represents the ideal glass transition temperature.

[0035] In this embodiment, the inputs are the pre-exponential factor A, the activation energy parameter B, the ideal glass transition temperature T0, and the relaxation time. and equilibrium modulus The glass viscoelastic model was used to simulate the preset heating and pressurization curves, and a preliminary set of process parameters was optimized.

[0036] In actual production, multiple sensors are used to collect the temperature of the mold, the applied pressure, and the mold closing displacement in real time. The mold closing displacement indirectly reflects the glass deformation.

[0037] First, calculate the current real-time viscosity of the glass based on the actual temperature T. Then the real-time viscosity Real-time stress and real-time response The parameters are then substituted into the glass viscoelastic model for inverse calculation or state estimation to determine whether the current rheological state of the glass deviates from expectations. Through filtering or optimization algorithms, the model parameters are slightly corrected to ensure that the digital model remains consistent with the physical process. Furthermore, based on the current state and future pressure changes, the short-term filling condition of the glass can be predicted.

[0038] Finally, the calculated state information is compared with the target state, and the internally included model is used for rapid rolling optimization to calculate the optimal adjustment amount. If the glass filling is too slow, the temperature is slightly increased to reduce the viscosity to the target range; if uneven deformation is detected, the temperature in different regions is adjusted or the pressure curve is modified to achieve uniform flow.

[0039] Furthermore, in the glass thermoforming process, after the mold is preheated, the glass blank is loaded into the mold and enters the second stage of heating in Step 2, so that the glass reaches the temperature corresponding to the target forming viscosity uniformly and without thermal shock, providing a consistent material state basis for subsequent pressure forming. In particular, the traditional fixed heating program is difficult to dynamically respond to real-time changes in furnace temperature distribution and blank heat capacity, which can easily lead to excessive temperature difference, internal stress, or warping defects.

[0040] Step 202: Minimize the time from the start of heating to the target time. The temperature difference between the glass surface and the core accumulates, ensuring that the temperature T(t) at any given time precisely reaches the temperature corresponding to the target viscosity. , is represented as: ; In the formula, This indicates the real-time temperature difference between the surface and the core. This represents the weighting coefficient, specifically the endpoint temperature accuracy weighting factor. Indicates the target temperature; Indicates the target viscosity; Indicates the target time.

[0041] The constraints are as follows: Heating rate is limited to prevent thermal shock cracking: ; Temperature uniformity within the heating zone is constrained to ensure synchronous heating across all areas: ; In the formula, Indicates the maximum heating rate; Indicates the temperature of the heating zone; Indicates average temperature; This indicates the tolerance for temperature uniformity.

[0042] In this embodiment, the temperatures of each heating zone, the glass surface, and the core are collected in real time, and combined with a glass heat transfer model, the temperature difference over a future period is predicted. The changing trend. Rolling optimization solves the above constrained optimization problem in each control cycle to obtain the optimal power setting curve for each heating zone in the future time domain, minimizing the integral of the squared temperature difference and ensuring that the final temperature approaches the target value.

[0043] The system implements only the optimal control command for the current moment, then re-acquires actual temperature data in the next cycle, corrects model prediction errors, and performs optimization calculations again, dynamically responding to thermal disturbances and model uncertainties in a cyclical manner. Specifically, by adjusting the power distribution of each heating zone, it ensures that the glass heats up smoothly within the rate limit, while maintaining the temperature difference between regions within the allowable range, avoiding localized overheating or insufficient heating.

[0044] Furthermore, after the workpiece temperature reaches the set forming point, the optimal pressurization curve is planned and executed to overcome the influence of material property fluctuations and mold geometric complexity, thereby achieving high-fidelity microstructure replica architectural glass.

[0045] At the initial pressurization moment, the initial rheological state of the glass melt is acquired using a sensor embedded in the mold, and its real-time viscosity is estimated by inversion, providing key process parameters for subsequent adaptive control. Then, the acquired real-time viscosity and preset filling time are used to calculate and generate a time-varying optimal pressure control curve.

[0046] Step 203: When the pressure head begins to move and comes into contact with the glass, the sensor embedded in the mold synchronously monitors the initial contact pressure P0. At the same time, the flow velocity v0 of the glass melt under the initial pressure is obtained through a displacement sensor or a pre-set calibration channel in the mold.

[0047] Substituting the above measured data with known mold clearance geometric parameters, such as characteristic clearance height h, flow characteristic length L, and shape factor K, into the following simplified fluid dynamics model: ; in, Indicates the real-time viscosity of the glass melt; The initial contact pressure is measured by a sensor embedded in the mold at the moment of pressurization, reflecting the resistance overcome when the glass begins to flow; H represents the critical gap height of the mold, which directly affects the flow resistance; v0 represents the initial flow velocity of the glass, which can be obtained indirectly through a pre-set micro-detection channel in the mold or through the initial pressure change rate; K represents the geometric shape factor, which is a constant related to the cross-sectional shape of the mold cavity; L represents the flow characteristic length, which refers to the distance of the glass from the inlet to the sensor position or to the end of the mold cavity.

[0048] Obtain real-time viscosity estimates Then, the pressure command P(t) for the entire process from the current moment to the completion of filling is planned. This includes a built-in flow resistance function strongly correlated with the three-dimensional geometry of the mold. The function is the filled volume. The mapping, whose value changes dynamically with the filling process, quantitatively describes the flow resistance at various points within the mold cavity. For example, when flowing through narrow textures... As the value increases, when flowing through open areas As the value decreases, this function can be pre-calculated through offline CFD simulation or updated online using multi-sensor data.

[0049] Furthermore, the flow resistance function Defined as the mapping relationship between the flow resistance within the mold cavity and the filled volume, it is generally expressed as: ; Where V is the filled volume. The flow resistance characteristics of the i-th mold region can be the initial filling section, texture replication section, end venting section, etc. This represents the weighting coefficient for that region.

[0050] For example, typical data: initial fill volume of the fill segment is 0-30%. ; Texture replica segment fill amount 30-80%, ; The final exhaust section is filled to 80-100%. .

[0051] Overall real-time viscosity Flow resistance function and remaining time The control pressure for the next moment is calculated using the following formula per second:

[0052] In the formula, Indicates basic pressure; This represents the instantaneous total flow resistance encountered at the current filling front. This value increases with increasing viscosity and narrowing of the flow channel.

[0053] A negative feedback loop was constructed: when flow resistance increases or viscosity is too high, P(t) is immediately increased proportionally to maintain the necessary flow rate; conversely, the pressure is decreased. Meanwhile, the remaining time... Ensure the entire filling process is strictly controlled to prevent premature cooling of the front-end glass.

[0054] Furthermore, at the moment from pressurization to the end of the holding period, cooling does not begin immediately. Instead, the stress state inside the glass component is first determined by taking into account the final pressure of the holding period.

[0055] Step 204: Based on the three-dimensional temperature distribution within the glass at this moment and the viscoelastic behavior of the material itself, calculate the initial residual stress field. , is represented as: ; Represents the spatial coordinates of the mold; This indicates a fast finite element solver for on-site calculations on the production line; This indicates the final holding pressure, the stable pressure value acting on the glass mold or glass material at the end of the holding stage; This represents a viscoelastic constitutive model that describes the relationship between stress, strain, time, and temperature in glass at high temperatures. The output includes the initial residual stress field. A complete three-initial-stress tensor field is used as the input parameter for subsequent cooling.

[0056] Cooling rate decision: ; in, The critical cooling rate determined by the cooling rate decision; Indicates the maximum initial tensile stress; d represents the thickness of the glass product; C s Represents the shape complexity factor; The base cooling rate is determined by the product thickness and geometry. The thicker and more complex the glass product, the slower the base cooling rate. This represents the stress-sensitive attenuation coefficient, which is determined by material properties and process safety margin.

[0057] Maximum initial tensile stress The larger its value, the stronger the exponent. The smaller the value, the lower the critical cooling rate. .

[0058] This embodiment proposes a molding method for building energy-saving glass, including: A. Model predictive control during the heating phase: While meeting the heating rate limit and temperature uniformity constraint, minimize the temperature difference between the glass surface and the core, and ensure that the temperature corresponding to the target viscosity is accurately reached at the target time.

[0059] Based on real-time temperature data and combined with a heat transfer model, an optimization problem is solved in each control cycle to dynamically calculate the optimal power setting for each heating zone in the short term, so as to heat the glass smoothly and uniformly.

[0060] B. Online rheological control during the pressurization phase: At the start of pressurization, the current viscosity of the glass melt is estimated in real time by using the initial contact pressure and initial flow velocity, combined with the mold geometry parameters, and by using simplified fluid dynamics formulas.

[0061] Based on real-time viscosity A predefined mold flow resistance function Φ, which varies with the filling volume (through CFD simulation), and the remaining preset filling time are used to calculate and adjust the pressure P(t) required for the next moment in real time.

[0062] When increased flow resistance is detected due to increased viscosity or narrowed flow channels, the pressure is automatically increased proportionally to maintain the filling speed; conversely, the pressure is decreased. This ensures that even complex textured molds can be filled uniformly and completely, and that the filling process is completed on time.

[0063] C. Stress-oriented decision-making during the cooling stage: At the end of the pressure holding period, a fast finite element solver is used to quickly calculate the initial residual stress field inside the glass product by combining the final pressure holding pressure, the three-dimensional temperature distribution inside the glass, and the viscoelastic model.

[0064] Based on the calculated maximum initial tensile stress, product thickness, and shape complexity, a safe critical cooling rate is dynamically determined. Areas with high stress are cooled at a slower rate to safely release stress and prevent cracking or bursting.

[0065] Example 2 Based on the above embodiments, referring to Figure 3, this embodiment further proposes a molding equipment for building energy-saving glass, comprising: Frame and mold closing mechanism 10: The overall structure is supported by a high-strength frame. The mold closing mechanism consists of an upper mold plate, a lower mold plate, guide pillars and a locking device to ensure that the mold is accurately aligned and does not deviate under high pressure.

[0066] Mold Unit 20: Includes an upper mold and a lower mold. The mold material is high-temperature resistant, oxidation resistant, and low thermal expansion coefficient high-grade alloy steel (such as H13), graphite, or ceramic. The cavity surface is coated with graphite-based or boron nitride release agent and is equipped with sensor mounting holes. Heating unit 30: It adopts a heating device with independent temperature control in each zone, which can be a box furnace, tunnel kiln or electric heating plate / induction heating module integrated on a molding press. Each heating zone is equipped with a thermocouple to achieve precise temperature control of ±2°C within the range of 600–850°C.

[0067] Pressurizing unit 40: A press driven by hydraulic or servo motor, with a pressure range of 5–20 MPa. It can programmably control the pressurizing speed, holding time, and pressure curve. The pressure head is equipped with a displacement sensor to monitor the mold closing status in real time.

[0068] Cooling unit 50: includes in-mold cooling channels and an independent annealing furnace, with adjustable cooling rate, supporting gradient cooling from molding temperature to room temperature to prevent glass from cracking.

[0069] Control Unit 60: Based on an industrial computer or PLC, integrating the following functional modules: Model Predictive Control Module 601: Based on the glass viscoelastic model and real-time collected temperature, pressure, and displacement data, it continuously optimizes the heating and pressurization process parameters; Online rheology control module 602: Real-time viscosity is inverted by initial contact pressure and flow velocity, and the pressure curve is dynamically adjusted to ensure complete filling; Stress-oriented decision module 603: Combines a fast finite element solver to calculate the initial residual stress field and determine the safe cooling rate; Input module 604: Provides process parameter setting, real-time monitoring, fault alarm and data logging functions.

[0070] In this embodiment, the mold cavity in the mold unit 20 is precisely machined according to the three-dimensional shape and surface texture of the product, and is equipped with venting grooves and overflow grooves; thermocouples and pressure sensors are pre-embedded inside the mold for real-time monitoring of glass temperature and flow resistance; a centering guide mechanism is provided between the upper mold and the lower mold to ensure mold closing accuracy; the mold surface is polished and coated to reduce glass adhesion and extend mold life.

[0071] Furthermore, the heating units 30 are distributed around the mold and on the upper and lower templates to achieve independent temperature control in multiple areas; PID or model predictive control algorithms are used to ensure that the temperature difference between the surface and the core of the glass blank is minimized during the heating process; segmented heating programs are supported, and the heating rate can be precisely controlled in the range of 5–15°C / min.

[0072] Furthermore, the press in the pressurizing unit 40 is controlled by a servo motor or a proportional hydraulic valve, with a pressure resolution of 0.1 MPa; the pressure head displacement accuracy is ≤0.01 mm, and the glass filling status can be fed back in real time; it has a built-in flow resistance function Φ and viscosity estimation model to achieve adaptive pressure regulation.

[0073] Furthermore, the cooling unit 50 is equipped with a cooling medium flow channel (water or oil), which can start gradient cooling after the pressure holding is completed; the cooling rate is automatically adjusted according to the stress decision module output, supporting both slow annealing and fast tempering modes; it is equipped with a forced air cooling or water mist cooling device for the final cooling of the product.

[0074] In this embodiment, the mold is cleaned, sprayed with a release agent, and preheated to a set temperature. The glass preform is cleaned, dried, and then placed into the lower mold by a robotic arm. The temperature is increased according to an optimized curve, and the control system adjusts the power of each zone in real time to ensure the glass uniformly reaches the temperature corresponding to the molding viscosity. After mold closing, the pressure system applies pressure according to an adaptive pressure curve, monitors the filling status in real time, and dynamically adjusts the pressure to ensure complete texture replication. After pressure holding, the cooling system performs gradient cooling at the rate output by the stress decision module until the mold is opened at a safe temperature. After the product is removed, it undergoes edge grinding, tempering, optical inspection, and packaging to complete the glass product.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A molding method for building energy-saving glass, characterized in that, include: Heating stage: The glass preform placed in the mold is heated to the forming temperature range. During this process, a viscoelastic model of glass is established to describe the relationship between stress, strain and time. The viscoelastic model of glass is as follows; ； In the formula, This represents the stress experienced by the material at time t. This represents the strain experienced by the material at time t; The relaxation time is the time required for the stress of the i-th molecular or structural unit inside the material to decay to 1 / e of its initial value when it responds to an external force. It represents the equilibrium modulus, which is the proportional relationship between strain after complete relaxation and stress. Indicates viscosity; The heating power is dynamically adjusted based on the model predictive control method to minimize the temperature difference between the surface and core of the glass preform and to make it reach the temperature corresponding to the target viscosity at the target time. Pressurization stage: After reaching the molding temperature range, pressure is applied to the mold to form the glass. During this process, the current viscosity of the glass is calculated in real time based on the initial contact pressure and initial flow velocity. Based on the real-time viscosity, the mold flow resistance function that dynamically changes with the filling volume, and the remaining filling time, the applied pressure is calculated and adjusted in real time to control the complete filling of the mold cavity by the glass melt. In the pressurization stage, the control pressure at the next moment is calculated by combining the real-time viscosity, flow resistance function, and remaining time. The real-time inversion of the current viscosity of the glass based on the initial contact pressure and the initial flow velocity includes: when the indenter starts to move and comes into contact with the glass, the sensor embedded in the mold synchronously monitors the initial contact pressure, and at the same time, the flow velocity of the glass melt under the initial pressure is obtained through the displacement sensor or the pre-set calibration channel in the mold. The measured data and known mold clearance geometry parameters are substituted into a simplified fluid dynamics model. The fluid dynamics model is used to estimate the real-time viscosity of the glass melt, which is related to the flow characteristic length, geometry factor, initial flow velocity of the glass, critical clearance height of the mold, and initial contact pressure. Cooling stage: After the pressure holding is completed, based on the final pressure holding pressure, the three-dimensional temperature distribution inside the glass and the viscoelastic model, the initial residual stress field inside the glass product is quickly calculated, and the safe cooling rate is dynamically decided and executed according to the maximum tensile stress value in the initial residual stress field, the product thickness and shape complexity.

2. The method for molding energy-saving building glass according to claim 1, characterized in that, During the heating phase, the model predictive control method includes: Minimize the accumulated temperature difference between the glass surface and the core from the start of heating to the target time, and constrain the endpoint temperature to precisely reach the temperature corresponding to the target viscosity.

3. The method for molding energy-saving building glass according to claim 2, characterized in that, The model predictive control method further includes: the heating rate not exceeding the preset maximum heating rate; and the temperature difference between each heating zone and the average temperature not exceeding the preset temperature uniformity tolerance.

4. The method for molding energy-saving building glass according to claim 1, characterized in that, The flow resistance function is a mapping of the filled volume, and its value changes dynamically with the filling process, quantitatively describing the flow resistance at various points within the mold cavity.

5. The method for molding energy-saving building glass according to claim 1, characterized in that, During the cooling stage, the initial residual stress field is calculated based on the three-dimensional temperature distribution within the glass body and the viscoelastic behavior of the material itself.

6. The method for molding energy-saving building glass according to claim 5, characterized in that, During the cooling stage, the cooling rate decision represents the critical cooling rate, maximum initial tensile stress, glass product thickness, shape complexity factor, basic cooling rate, and stress-sensitive attenuation coefficient determined by the cooling rate decision.

7. The method for molding energy-saving building glass according to any one of claims 1-6, characterized in that, Before the heating step, a mold pretreatment step is also included: cleaning the mold cavity and applying a release agent, preheating the mold to 600-800°C; and cleaning and drying the glass blank.

8. A molding apparatus for building energy-saving glass, comprising the molding method for building energy-saving glass as described in any one of claims 1-7, characterized in that, The building energy-saving glass molding equipment includes: Frame and mold closing mechanism (10); Mold unit (20) mounted on the frame and mold closing mechanism (10); Heating unit (30) for heating the glass blank inside the mold unit (20); A pressurizing unit (40) for applying pressure to the glass preform; Cooling unit (50) for cooling molded products; A control unit (60) is electrically connected to the heating unit (30), the pressurizing unit (40), and the cooling unit (50). The control unit (60) includes: The model prediction control module (601) is used to control the heating unit (30). An online rheology control module (602) is used to control the pressurization unit (40); A stress-directed decision module (603) is used to control the cooling unit (50).

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