Technological Evolution And Key Elements Of Electronic Glass Molding Processes

As a core substrate in the display and touch fields, the molding process of electronic glass directly determines the thickness uniformity, surface quality, and adaptability to subsequent processing. With the trends towards ultra-thinness, large size, and flexibility, innovation in molding technology has become a crucial factor driving breakthroughs in electronic glass performance.

Currently, the mainstream electronic glass molding processes include float glass, overflow pull-down glass, and slot pull-down glass, each with its own technological focus. The float glass process uses molten tin as the molding medium. After the molten glass flows from the furnace through a channel into the tin bath, it naturally flattens due to density differences and cools and solidifies with the flow of molten tin. The advantage of this process is that it can produce glass substrates with large widths (up to 3 meters or more) and uniform thickness, with excellent surface flatness, suitable for the needs of large-size display panels such as televisions and monitors. However, the tin bath environment requires strict control of oxygen content and temperature gradient to avoid tin oxidation contamination or ripple defects on the glass surface.

The overflow-pull method uses a specially designed platinum channel to guide molten glass to a wedge-shaped overflow brick. Gravity causes the liquid to overflow symmetrically along both sides of the brick and converge downwards, where it is then drawn into shape by a pulling machine. The core of this process lies in precisely controlling the matching of overflow speed and pulling rate, enabling the production of extremely thin glass (0.03-0.7mm) with nearly identical top and bottom surfaces. This effectively reduces subsequent grinding and polishing processes, making it particularly suitable for small-sized, high-precision touchscreens for mobile phones and tablets. However, it has stringent requirements for the viscosity and temperature uniformity of the molten glass; the stability of the components during the melting process directly affects the forming yield.

The slit-pull method uses a narrow, elongated outlet to directly extrude molten glass vertically, which is then rapidly cooled and pulled to form a continuous glass ribbon. This process offers high flexibility, allowing for multiple thickness specifications by adjusting the outlet width and pulling speed. The equipment also has a relatively small footprint, making it suitable for small to medium batch production with diverse product types. However, it requires addressing edge stress concentration and thickness fluctuations, often achieved by optimizing the outlet shape and adding auxiliary cooling devices to improve product consistency.

In recent years, with the surge in demand for flexible electronic glass, molding processes are being upgraded towards "precision shape control" and "low damage." For example, the introduction of laser thickness measurement and closed-loop feedback systems to correct drawing parameters in real time, combined with ultra-clean workshop environmental control to reduce microparticle contamination, and the development of new refractory materials to reduce the interaction between molten glass and the container walls during molding. These technological advancements not only improve the molding efficiency and quality of electronic glass but also provide a material foundation for emerging applications such as foldable and rollable screens.

The continuous refinement of molding processes is driving electronic glass from "usable" to "superior," laying a solid foundation for the innovative development of the display industry.