Manufacturing principle of waterproof silicone ring for precision electronic components?

As an indispensable component of modern electronic devices, the waterproof silicone ring for precision electronic parts is not only related to the waterproof performance of the product, but also directly affects the overall quality and user experience of the equipment.

1、 Material selection: The superior performance of silicone rubber

Silicone rubber, as the main raw material for waterproof silicone rings, has a series of excellent characteristics, making it the preferred choice for waterproof structural components in electronic products. Silicone rubber has characteristics such as heat and cold resistance, high elasticity, high compression rate, oxidation resistance, electrical insulation, and heat dissipation. These characteristics ensure the stability and durability of silicone rings under different temperatures, humidity, and chemical environments.
Silicone rubber is divided into two types: solid silicone and liquid silicone. Solid silicone is mainly used for molded products, such as silicone sleeves, silicone tableware, silicone buttons, etc. Liquid silicone is mainly used for extruded products, such as silicone nipples, silicone tubes, etc. In the manufacturing of waterproof silicone rings for electronic products, liquid silicone is more popular due to its higher precision and plasticity. Especially the liquid silicone injection molding technology (LSR/LIM) can produce waterproof silicone rings with smaller volume and higher precision, meeting the high requirements of modern electronic devices for waterproof performance.

2、 Molding process: the key to precision manufacturing

The molding process is crucial in the manufacturing process of waterproof silicone rings for precision electronic products. Common molding processes include compression molding, splicing, and injection molding.
1. Compression molding
The compression molding process uses molds to heat and shape raw materials, suitable for sealing rings with complex shapes. Compression molding can produce silicone sealing rings of any structure, including rectangular, circular, irregular, and even special structures such as inverted grooves. However, the production cost of the compression molding process is relatively high, and the production capacity is not high when the size is too large. However, due to its one-piece molding characteristics, compression molding can ensure seamless connection of the sealing ring, thereby improving the sealing effect.
2. Splicing method
The splicing method is suitable for producing large silicone sealing rings. By cutting the elongated sealing strip produced by extrusion molding into the required length and bonding it into a circle, this production method is not limited by length and has lower mold costs. However, the drawback of the splicing method is that structures such as right angles cannot be completely filled, resulting in gaps and affecting the sealing effect. In addition, the sealing ring that is connected into a circle also has poorer elasticity and ductility, because after cutting, hot glue is applied to the incision and then placed in the connecting mold for vulcanization, resulting in more obvious joints.
3. Injection molding
Injection molding technology is one of the most advanced processes in the manufacturing of waterproof silicone rings for precision electronic products. It requires the use of a silicone injection molding machine and a pressing machine to press the preheated water thick rubber material into the mold cavity of the hot mold through the nozzle of the injection molding machine. Injection molding is a continuous molding method with high output value and easy automation production. Although the material and mold costs are high, its precision and efficiency make it an ideal choice for manufacturing complex composite seals, tire treads, rubber hoses, and other products.

3、 Quality control: the key link to ensure waterproof performance

In the manufacturing process of waterproof silicone rings for precision electronic products, quality control is a key link to ensure waterproof performance. This includes precise mixing of raw materials, control of finished products during injection molding, control of mold temperature, and optimization of product design.
1. Accurate mixing of raw materials
LSR is a two-component raw material consisting of A and B, which must be thoroughly mixed in a precise 1:1 ratio before injection molding. If it is a colored liquid silicone product, the color paste ratio must also be precisely controlled. The precise mixing of raw materials ensures the uniformity and consistency of the silicone ring, thereby improving its waterproof performance.
2. Finished product control during injection molding process
The finished product control during the injection molding process includes the position and accuracy of the parting line, shrinkage rate, position of the injection port, vacuum pumping, and demolding technology. Pre considering the position and accuracy of the parting line can help avoid air entrainment and welding, and prevent burrs. Although LSR does not shrink during injection molding, due to its extremely high coefficient of thermal expansion, it typically shrinks by 2% to 3% after demolding and cooling. Therefore, the shrinkage rate of the actual product needs to be considered during design. The position of the injection port also needs to be determined based on the product shrinkage rate. When designing the parting line, ensure that the mold is sealed and use a vacuum pump to evacuate all cavities to avoid the generation of bubbles and gaps. When demolding, the demolding techniques of distillation column tray, push top pin, and air push top are generally used.
3. Control of mold temperature
LSR is formed by vulcanization during heating, and the temperature distribution inside the mold must be controlled uniformly. The control of mold temperature is crucial for the forming accuracy and physical properties of silicone rings. Excessive or insufficient temperature can cause deformation or uneven shrinkage of the silicone ring, thereby affecting its waterproof performance.
4. Optimization of product design
Optimizing product design is also an important aspect of ensuring waterproof performance. For example, the design of the phone groove needs to be closely adhered to the silicone pad, and the size and cross-sectional area of the groove must be adapted to the deformation of the pad. The design principle is that the cross-sectional area of the groove is the cross-sectional area of the pad, so that the pad can be fully accommodated in the groove after compression, and the edge of the groove and the cover plate can be in close contact, achieving waterproof effect. In addition, it is necessary to consider the compatibility between waterproof silicone rings and other accessories, such as secondary molding with metal accessories.

4、 Technological Innovation and Future Development

With the continuous development of electronic products and the increasing demand for waterproof performance from consumers, the manufacturing technology of precision waterproof silicone rings for electronic products is also constantly innovating and developing. For example, using more advanced injection molding equipment and technology to improve the accuracy and efficiency of silicone rings; Develop new silicone rubber materials to improve the heat and cold resistance as well as chemical corrosion resistance of silicone rubber rings; Optimize product design, improve the compatibility and sealing effect between silicone rings and other accessories.
In the future, the manufacturing technology of waterproof silicone rings for precision electronic products will pay more attention to environmental protection and sustainability. For example, using bio based silicone rubber materials to reduce environmental pollution; Optimize production processes, reduce energy consumption and waste generation, etc. At the same time, with the popularization of technologies such as the Internet of Things and 5G communication, electronic products will become more intelligent and complex, and higher requirements have been put forward for the manufacturing of waterproof silicone rings. Therefore, continuous technological innovation and quality control will be important development directions in the manufacturing of waterproof silicone rings for precision electronic products in the future.