Vertically oriented glass casting mold

Abstract

The utility model relates to foundry technology field especially relates to a vertical directional glass casting mould, it contains four identical size L type cast iron unit, L type cast iron unit is set up as cast iron piece of right angle bending. L type cast iron unit is through end point butt joint or overlapping nested and is pasted and constitutes the mould with longitudinal cavity to make glass liquid can flow in the height direction of pouring opening based on mould. The technical scheme presented in the application not only significantly improves the quality and efficiency of glass casting, but also reduces defects, improves the yield and performance of products. These improvements not only improve the overall quality of the product, but also provide a more reliable material basis for subsequent processing and application, with wide application prospect and significant economic benefits.

Description

Technical Field

[0001] This utility model relates to the field of casting mold technology, and in particular to a vertically oriented glass casting mold. Background Technology

[0002] In cover glass manufacturing, the casting process is responsible for the core phase transition of the melt into a room-temperature solid, a process accompanied by three key transformations: 1) Dramatic change in viscosity: from 10 ^2 dPa·s molten state to 10 ^13 The brittle state of dPa·s spans 12 orders of magnitude; 2) Volume shrinkage; 3) Imbalance in thermal conduction: The thermal conductivity of glass melt is only 0.8~1.2 W / (m·K), which is much lower than that of mold materials [cast iron 38~54 W / (m·K)].

[0003] These drastic inherent physical changes, particularly the non-uniform cooling caused by thermal conductivity imbalance, pose a key challenge to quality control during the casting process. Specifically, the significant difference in thermal conductivity between the melt and the mold inevitably creates a steep temperature gradient during cooling. When the cooling rate exceeds 15°C / min, the temperature difference between the glass surface and the core can easily exceed 300°C. This extreme difference in thermal state induces significant non-uniform thermal stress concentration—considered the fundamental physical cause of defects such as the initiation of microcracks (e.g., microcracks, stress lines) and overall macroscopic deformation (e.g., warping) within the glass. Therefore, the casting process, as the core link in transforming the glass melt into a brittle solid, directly determines the physicochemical properties (e.g., strength, light transmittance, flatness) and product qualification rate of the final cover glass through its process control.

[0004] The current industry standard for cover glass casting is based on a horizontal casting mold with the mold cavity placed horizontally (i.e., horizontal casting). In this configuration, the molten glass flows primarily horizontally within an open or closed cavity and gradually cools and solidifies. However, this mainstream method suffers from two major technological flaws that severely limit product quality improvement: 1. Excessive density of streak defects: During horizontal flow solidification, glass components with different densities undergo longitudinal sedimentation and separation under gravity (i.e., component segregation), resulting in directional, visible flow-like streak defects on or inside the solidified glass surface. This macroscopic compositional inhomogeneity directly impairs optical uniformity and mechanical strength.

[0005] 2. Excessive Bubble Defect Density: Because the glass melt flows horizontally and the solidification front mainly advances vertically, bubbles trapped in the melt have difficulty rising to the free surface and escaping due to the combined effects of viscous resistance and buoyancy. They are easily trapped in the lower part of the glass block, especially in the central region along the thickness direction where the bubble concentration is highest. These residual bubbles are stress concentration points inside the product, significantly reducing mechanical reliability.

[0006] In view of the aforementioned technological status, and to address the inherent problem of high incidence of streaks and bubbles in traditional transverse casting processes, this invention designs and proposes an innovative mold solution—a vertically oriented casting mold with adjustable dimensions. This design changes the casting direction from horizontal to vertical (or near-vertical), utilizing transformative optimization of directional solidification kinetics to specifically improve melt flow patterns and the thermodynamic environment. This effectively suppresses gravity-induced component segregation (eliminating streaks) and promotes efficient bubble removal along the rising path (reducing bubble trapping rate), providing a more promising new approach to solving the problem of casting defects in cover glass.

[0007] Furthermore, on the one hand, there are differences in understanding among those skilled in the art; on the other hand, the inventors studied a large number of documents and patents when making this utility model, but due to space limitations, not all details and contents were listed in detail. However, this does not mean that this utility model does not possess the features of these prior art. On the contrary, this utility model already possesses all the features of the prior art, and the applicant reserves the right to add relevant prior art to the background art. Summary of the Invention

[0008] To address the aforementioned technical problems, the purpose of this utility model is to provide a vertically oriented glass casting mold, which aims to reduce defects such as streaks and bubbles on the cast glass bricks.

[0009] To achieve the above-mentioned effects of this utility model, the technical solution adopted by this invention is as follows: A vertically oriented glass casting mold comprises four identical L-shaped cast iron units, each L-shaped cast iron component bent at right angles. The L-shaped cast iron units are joined together at their endpoints or overlapped and nested to form a mold with a longitudinal cavity, allowing molten glass to flow through the pouring gate in the height direction of the mold.

[0010] According to a preferred embodiment, the length of the longitudinal cavity is 160 mm. The width of the longitudinal cavity is 20 mm. The height of the longitudinal cavity is 80 mm.

[0011] According to a preferred embodiment, the length ratio of the short arm to the long arm of the L-shaped cast iron unit is 1:1.

[0012] According to a preferred embodiment, the L-shaped cast iron unit is cast from gray cast iron, ductile iron, or vermicular graphite cast iron.

[0013] According to a preferred embodiment, the height direction (80 mm) is perpendicular to the ground, forming a side-up casting channel.

[0014] According to a preferred embodiment, the width of the cavity can be achieved by translating the molds on both sides of the cavity width.

[0015] According to a preferred embodiment, the surfaces of the L-shaped cast iron unit that participate in forming the cavity are all sandblasted.

[0016] According to a preferred embodiment, the surface roughness Ra of the L-shaped cast iron unit participating in the formation of the cavity is 0.8~1.6 μm. Preferably, the surface roughness Ra of the L-shaped cast iron unit participating in the formation of the cavity is 0.8 μm. Or, the surface roughness Ra of the L-shaped cast iron unit participating in the formation of the cavity is 1.6 μm.

[0017] According to a preferred embodiment, the L-shaped cast iron unit is provided with a boron nitride coating of 50-200 μm. Preferably, a 50-200 μm boron nitride coating is prepared by plasma spraying onto the surface of the L-shaped cast iron unit. This coating reduces the glass melt contact angle to below 30° and maintains the thermal conductivity of the mold at 15-25 W / (m·K).

[0018] The beneficial effects of this technical solution are: This application utilizes a vertical cavity configuration to optimize the heat transfer path. The vertical cavity configuration reconstructs the heat transfer path by setting the cavity height to be perpendicular to the ground, with a height of 80 mm. This design aligns the temperature gradient with the direction of gravity, effectively reducing lateral thermal convection, which is one of the main causes of stripe formation on the glass surface. In this way, the glass experiences more uniform stress during cooling, resulting in a more stable shape and significantly reducing the probability of stripe formation.

[0019] The bubble migration distance is shortened, and the expulsion time is reduced. By limiting the cavity height to 80 mm, the maximum bubble migration distance is also shortened to 80 mm. This significantly reduces the time for bubbles to rise and expel from the glass, decreasing the expulsion time by more than 60% compared to traditional molds. This improvement not only increases the transparency of the glass but also reduces stress concentration caused by bubbles, thereby enhancing the mechanical strength and durability of the glass.

[0020] Functional internal surface for synergistic temperature control. The inner surface of the mold employs an advanced functional design, using a boron nitride coating to balance the glass's solidification rate. This coating effectively regulates heat transfer during cooling, reducing peak thermal stress by 40-50%. This improvement not only reduces internal stress but also enhances the glass's structural uniformity and stability, further improving its optical and mechanical properties.

[0021] Defects in glass bricks have been significantly improved. The number of striation defects in glass ingots has been greatly reduced, and the striation density has been reduced to ≤3 striations / cm. 2 The improvement rate reached 75%. This significant improvement not only enhanced the visual appeal of the glass but also strengthened its optical properties, resulting in excellent performance in terms of light transmittance and refractive index uniformity. Simultaneously, the number of bubble defects larger than 0.1 mm in diameter was drastically reduced, to ≤1 defect / cm². 2 This improvement further enhances the transparency and structural integrity of the glass, reduces stress concentration caused by air bubbles, and thus strengthens the glass's mechanical strength and durability.

[0022] Deformation improvement. Edge warping deformation was significantly reduced to ≤0.1 mm, an improvement rate of ≥67%. This improvement is attributed to precise temperature management and optimized mold design, which resulted in more uniform stress on the glass during cooling, leading to a more stable shape and effectively preventing product scrap due to edge warping, thereby improving product yield and reliability.

[0023] In summary, the technical solution proposed in this application not only significantly improves the quality and efficiency of glass casting, but also reduces defects and increases product yield and performance. These improvements not only enhance the overall quality of the product, but also provide a more reliable material basis for subsequent processing and applications, demonstrating broad application prospects and significant economic benefits. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the mold structure; Figure 2 This is a schematic diagram of the structure of an L-shaped cast iron unit; Figure 3 This is a diagram illustrating the use of the mold; Figure 4 This is a structural diagram of one implementation of an L-shaped cast iron unit.

[0025] Figure Labels 100: L-shaped cast iron unit; 110: long arm; 120: short arm. Detailed Implementation

[0026] In the description of this utility model, the terminology is used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly defined.

[0027] To facilitate understanding and further explain the advantages of this utility model, the assembled vertically oriented casting mold is placed on a heating platform and heated. Through reasonable glass casting and annealing operations, the forming quality of the glass bricks is improved and glass defects are reduced.

[0028] The surface striation density of the glass brick was obtained by counting on a 1 mm × 1 mm grid using a 200x optical microscope.

[0029] The number of bubbles was obtained under a polarizing microscope using a glass cover plate cut from a glass brick to a size of 100*100*0.6 mm. The bubble density was calculated as the number of bubbles / total area.

[0030] Edge warping was measured using a high-precision imaging instrument on a glass cover plate cut from glass bricks to a size of 155*73*0.6 mm.

[0031] Example 1 This embodiment relates to a vertically oriented glass casting mold. This embodiment also relates to a vertically oriented glass casting mold with adjustable dimensions. This embodiment further relates to an L-shaped cast iron mold structure for supporting the backplane of electronic devices, and more particularly to a modular assembly system formed by combining multiple cast iron units of specific geometric shapes.

[0032] This structure makes full use of the high strength, high wear resistance and dimensional stability of cast iron material, and realizes a variety of assembly modes through precise physical configuration to adapt to the support and positioning requirements of electronic backplanes of different sizes and shapes.

[0033] The L-shaped cast iron unit 100 is made of gray cast iron or ductile iron, and its chemical composition meets the requirements of GB / T9439 or GB / T 1348 standards, exhibiting excellent compressive strength and wear resistance. The cast iron surface, after sandblasting, presents a uniform metallic gray color. Preferably, depending on the application environment, the L-shaped cast iron unit 100 requires rust prevention or hardening surface treatment.

[0034] Gray cast iron or ductile iron has a low coefficient of thermal expansion, which allows it to maintain dimensional stability even under fluctuating temperatures, ensuring the long-term reliability of the backplane support structure for electronic devices.

[0035] According to a preferred embodiment, the surface roughness Ra of the L-shaped cast iron unit 100 is 0.8~1.6 μm. Preferably, to improve the surface roughness, all surfaces of the L-shaped cast iron unit 100 that participate in forming the cavity are sandblasted.

[0036] Each L-shaped cast iron unit 100 consists of two mutually perpendicular arms, namely a long arm 110 and a short arm 120. The fixed length ratio of the long arm 110 to the short arm 120 is 1:1. The ratio of the extended length to the extended length of the short arm 120 is 3 to 4:1. Preferably, the standard length of the long arm 110 is 160 mm to 180 mm, the standard length of the short arm 120 is 160 mm to 180 mm, the arm width is uniformly 80 mm, and the thickness is 20 mm. Preferably, the end faces of both the long arm 110 and the short arm 120 are milled to form flat contact surfaces with a surface roughness Ra not exceeding 1.6 μm, ensuring a tight fit of the contact surfaces during assembly.

[0037] According to a preferred embodiment, all corners of the L-shaped cast iron unit 100 are designed with strict right angles, without rounded or chamfered transitions, and the inner and outer sides of the corners form a 90° angle, with the tolerance controlled within ±0.1 mm.

[0038] According to a preferred embodiment, for integrally molded glass casting, the corners of some L-shaped cast iron units 100 can also be set as rounded corners or chamfers.

[0039] According to a preferred embodiment, the surface of the arm body is provided with a plurality of positioning mark holes, the holes having a diameter of 2 mm and a depth of 5 mm, for assisting in assembly alignment.

[0040] According to a preferred embodiment, each arm body has a weight-reducing groove machined on its side, with a groove depth of 3 mm and a width of 10 mm, which reduces the overall weight while ensuring structural strength.

[0041] Four L-shaped cast iron units 100 form a closed rectangular frame through the close fitting of their vertical arms (i.e., short arms 120). According to a preferred embodiment, as... Figure 1 As shown, the long arm 110 of the first unit and the short arm 120 of the second unit interlock at a right-angle corner to form the first vertical connection; the long arm 110 of the second unit and the short arm 120 of the third unit are connected in the same way, and so on until the fourth unit is closedly connected to the first unit. The units achieve a stable connection through the friction of the contact surfaces and structural interlocking, requiring no additional fasteners. The gap between the contact surfaces of each unit does not exceed 0.05 mm, ensuring that the flatness error of the overall frame is less than 0.1 mm / m².

[0042] Preferably, the inner dimensions of the rectangular frame match the outer dimensions of the electronic device's back panel, and the back panel is restrained by four right-angle corners when placed on the inner side of the frame to prevent lateral displacement.

[0043] The mold involved in this embodiment is mainly used for glass molding of electronic device backplanes. Specifically, before use, each L-shaped cast iron unit 100 needs to be thoroughly cleaned to ensure that its interlocking surfaces and cavity surfaces are free of any dust, oil, or residual mold release agent particles from the previous molding. After cleaning, the unit can be preheated to a stable working temperature to reduce thermal shock with the molten glass. Then, the four clean L-shaped units are precisely assembled on the platform, ensuring that each tenon and groove is fully fitted, and confirming no wobbling by tapping or other methods. The assembled mold is moved to the injection station, and a predetermined amount of high-temperature molten glass is injected into the square cavity formed by the four units through the gating system above. The injection pressure and speed need to be precisely controlled according to the specific glass material properties. Figure 3 As shown, the excellent thermal conductivity of cast iron allows the molten glass to dissipate heat evenly within the mold cavity and gradually solidify. During this process, methods such as air cooling can be used to control the cooling rate. Once the glass part has cooled below its solidification temperature and the mold temperature has dropped to a safe operating range, demolding is performed. The demolding process is the reverse of the assembly process. Each unit is separated sequentially by gently tapping or using a dedicated demolding tool (applied to pre-defined non-critical areas on the unit). Due to the different shrinkage rate of glass compared to cast iron, the molded part usually separates naturally from the cavity. After removing the glass backplate product, the mold unit is inspected, cleaned, and maintained for future use.

[0044] The entire process highlights the modularity, repeatability, and high precision of the mold system, making it ideal for high-efficiency, high-quality mass production of glass backplates for electronic products.

[0045] Example 2 In addition to the standard rectangular assembly pattern described above, multiple L-shaped cast iron units 100 can also be asymmetrically combined to form trapezoidal or polygonal support structures. For example, the long arms 110 of two units can be reverse-connected to the short arms 120 of two other units to form an offset layout, which can accommodate protrusions or interface areas on the backplate. Furthermore, units can also be assembled by overlapping, that is, by adjusting the contact area of ​​the arms to fine-tune the frame size, thereby adapting to backplates of different specifications.

[0046] Example 3 Multiple L-shaped cast iron units 100 can also be connected by mortise and tenon joints.

[0047] At the end of each L-shaped cast iron unit 100, a tenon and mortise structure of matching size and shape is designed: one end of the long arm 110 is machined into a protruding tenon, and one end of the short arm 120 is machined into a matching recessed mortise (e.g., Figure 4(As shown). Preferably, the tenon has a square, trapezoidal, or other cross-section suitable for mortise and tenon connections. For example, a trapezoidal structure has a width that gradually decreases from the base to the end, forming a self-locking bevel. The shape of the tenon is completely complementary to this bevel, creating an interference fit effect when they mate, ensuring a tight and secure connection. Both the inner and outer surfaces of the L-shaped cast iron unit 100 are ground, with a surface roughness Ra not exceeding 1.6 μm, to ensure the smoothness of the glass forming surface and smooth demolding.

[0048] Example 4 The following are five sets of exemplary embodiments and two sets of comparative experimental data designed based on the invention's effect indicators. All samples were cast using the same batch of lithium aluminum silicon glass melt (SiO2 68.5wt%, Al2O3 19.2wt%, Li2O 4.8wt%, P2O5 2.5wt%, ZrO2 3.0wt%, clarifying agent 2.0wt%). The boron nitride coating thickness was 150±10 μm, the vertical casting cavity 1 had dimensions of 60×20×80 mm, and the casting temperature was 1450±10℃. The effects of the mold before and after implementation are shown in Table 1 below.

[0049] Table 1

[0050] As shown in Table 1, based on the mold involved in this application, through longitudinal casting and adjustments to the surface roughness of the mold, significant improvements were achieved in several key quality indicators of the final formed glass products while ensuring heat dissipation, fluidity, and gravity flow. Specifically, the stripe density on the glass surface was significantly reduced, which not only improved the visual effect of the glass but also enhanced its optical properties, resulting in excellent performance in terms of light transmittance and refractive index uniformity. Simultaneously, the significant reduction in bubble density further improved the transparency and structural integrity of the glass, reducing stress concentration problems caused by bubbles, thereby enhancing the mechanical strength and durability of the glass. Furthermore, the risk of edge warping was effectively controlled, thanks to precise temperature management, reasonable mold design, and optimized casting parameters. This resulted in more uniform stress distribution and more stable shape during the cooling process, effectively avoiding product scrap due to edge warping and improving product yield and reliability. These improvements not only enhanced the overall quality of the product but also provided a more reliable material basis for subsequent processing and applications.

[0051] It should be noted that the specific embodiments described above are exemplary. Those skilled in the art can devise various solutions inspired by the disclosure of this utility model, and these solutions all fall within the scope of this utility model and its protection. Those skilled in the art should understand that this utility model specification and its drawings are illustrative and not intended to limit the scope of the claims. The protection scope of this utility model is defined by the claims and their equivalents.

Claims

1. A vertically oriented glass casting mold, characterized in that, It comprises at least four L-shaped cast iron units (100) of the same size, wherein the L-shaped cast iron units (100) are configured as right-angled bent cast iron parts. The L-shaped cast iron units (100) are joined together by end-point docking or overlapping nesting to form a mold with a longitudinal cavity, so that the molten glass can flow at the pouring port in the height direction of the mold.

2. The vertically oriented glass casting mold according to claim 1, characterized in that, The surface roughness of the L-shaped cast iron unit (100) that participates in forming the cavity is 0.8~1.6 μm.

3. The vertically oriented glass casting mold according to claim 2, characterized in that, The surface of the L-shaped cast iron unit (100) that participates in forming the cavity is sandblasted.

4. The vertically oriented glass casting mold according to claim 2, characterized in that, The L-shaped cast iron unit (100) is provided with a boron nitride coating of 50~200 μm to reduce the glass melt contact angle to below 30° and keep the thermal conductivity of the mold at 15~25 W / (m·K).

5. The vertically oriented glass casting mold according to claim 2, characterized in that, The surface roughness of the L-shaped cast iron unit (100) that participates in forming the cavity is 1.6 μm.

6. The vertically oriented glass casting mold according to claim 1, characterized in that, The length ratio of the short arm (120) to the long arm (110) of the L-shaped cast iron unit (100) is 1:

1.

7. The vertically oriented glass casting mold according to claim 1, characterized in that, The L-shaped cast iron unit (100) is made of gray cast iron, ductile iron or vermicular graphite cast iron.

8. The vertically oriented glass casting mold according to claim 1, characterized in that, The longitudinal cavity dimension is 160 mm in length.

9. The vertically oriented glass casting mold according to claim 1, characterized in that, The width of the longitudinal cavity is 20 mm.

10. The vertically oriented glass casting mold according to claim 1, characterized in that, The height of the longitudinal cavity is 80 mm.

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