How to reduce internal stress and avoid the risk of spontaneous explosion during the processing of rice cooker cover glass?
Release Time : 2026-01-13
In the processing of rice cooker cover glass, the generation and distribution of internal stress are key factors affecting its safety and stability. If internal stress is not effectively controlled, it may lead to spontaneous breakage during use, seriously threatening user safety. Therefore, reducing internal stress and avoiding the risk of spontaneous breakage is a core task in the processing of rice cooker cover glass.
Stress in glass is mainly classified into three categories: thermal stress, structural stress, and mechanical stress. Thermal stress originates from temperature differences and is divided into temporary and permanent stress. Temporary stress changes with the temperature gradient and disappears once the temperature reaches equilibrium; however, permanent stress persists even after temperature equilibrium, significantly affecting the mechanical strength and stability of the glass. Structural stress is caused by inhomogeneity in the internal structure of the glass, such as compositional differences or stress generated during the molding process. This type of stress also persists for a long time and is difficult to eliminate by simple methods. Mechanical stress is stress concentration caused by external forces during processing or use; if not handled properly, it can easily become a cause of spontaneous breakage.
In the processing of rice cooker cover glass, heat treatment is a crucial step in reducing internal stress. By precisely controlling the heating and cooling rates, the stress distribution within the glass can be effectively altered. Annealing is a commonly used method, involving heating the glass to a temperature close to its transformation temperature and holding it at that temperature for a certain time to relax the stress. Subsequently, slow cooling redistributes the stress, eliminating permanent stress. Temperature control is crucial in this process; excessively high or low temperatures can affect the stress relief effect and even lead to the generation of new stress.
Besides heat treatment, chemical treatment is also an effective means of reducing internal stress. By forming a protective film on the glass surface, stress concentration can be reduced, thereby achieving stress relief. For example, oxidation or ion exchange treatment can alter the chemical composition of the glass surface, enhancing its stress resistance. These methods are simple to operate, but require the selection of appropriate chemical solutions and corrosion conditions to avoid damaging the glass surface and affecting its transparency and optical properties.
Mechanical processing also plays an important role in the processing of rice cooker cover glass. Through physical means such as grinding and polishing, stress concentration areas on the glass surface can be directly removed, reducing the accumulation of internal stress. However, such methods may affect the transparency and surface quality of the glass. Therefore, strict parameter control is necessary during processing to ensure quality. Furthermore, for tempered glass, processes such as opening holes and chamfering should be avoided to prevent damage to the established stress structure and increase the risk of spontaneous breakage.
The impact of stress must also be considered during the design phase of rice cooker cover glass. Proper hole placement, edge treatment, and overall structural layout can effectively reduce stress concentration and lower the risk of spontaneous breakage. For example, avoiding design flaws such as openings too close to corners, excessively small chamfers, or too many openings can reduce stress accumulation during use. For curved glass panels, special attention must be paid to the uniformity of stress distribution to avoid stress concentration caused by direct load-bearing.
In addition, after processing, rice cooker cover glass requires rigorous testing and quality control. Stress detection equipment can promptly identify areas of stress concentration within the glass, allowing for appropriate intervention. Regular maintenance of processing equipment to ensure optimal operating conditions is also crucial for reducing internal stress and preventing spontaneous breakage.