What is the difference between liquid silicone encapsulation injection molding process and injection molding?

There are significant differences between the liquid silicone encapsulation injection molding process and injection molding in terms of material properties, process, application areas, and final product characteristics. These two molding technologies each have unique advantages and applicable scenarios, and understanding their differences is crucial for choosing the appropriate production process.

1、 Differences in material properties

Liquid Silicone Rubber (LSR) is a high-performance polymer material with excellent elasticity, temperature resistance, aging resistance, and chemical corrosion resistance. LSR is usually divided into two components, one containing a catalyst and the other containing a crosslinking agent. After mixing the two, a chemical reaction occurs to achieve curing. This material can tightly adhere to the surface of the mold during the injection molding process, forming a smooth and delicate surface effect, and no by-products are produced after curing, making it highly environmentally friendly.

Injection molding: The materials used in injection molding are mostly thermoplastic, such as polyethylene, polypropylene, ABS, etc. These materials have fluidity after heating and can be injected into the mold through an injection molding machine to cool and solidify into shape. Thermoplastic does not require chemical reactions during the molding process and mainly relies on cooling and solidification. Its material properties are mainly reflected in good processability, mechanical properties, and thermoplasticity.

2、 Differences in Technological Processes

Liquid silicone encapsulation injection molding: This process is complex and precise, requiring a high degree of process control and professional knowledge. Firstly, it is necessary to load the liquid silicone gel of components AB into the barrel of the injection machine, and ensure that the two components are mixed in a certain proportion through a precise metering system. The mixed silicone is injected into the mold under high pressure, and the mold needs to be heated to 160 to 220 degrees Celsius to promote the curing of the silicone. During the solidification process, the design of the mold needs to consider the setting of exhaust holes to ensure the smooth discharge of air inside the mold and avoid the generation of bubbles and burrs. The solidification speed of liquid silicone is fast, and it can complete the transition from liquid to solid in a short time, thereby achieving efficient production.

Injection molding: The process of injection molding is relatively simple, and the main steps include melting, injection, pressure holding, cooling, and demolding of plastic pellets. After the plastic pellets are heated and melted in the barrel, they are injected into the mold through the rotation and advancement of the screw, and the plastic inside the mold gradually solidifies during the cooling process. The temperature control of injection molding mainly focuses on the heating and cooling of the barrel and mold to ensure that the plastic can melt and solidify smoothly.

3、 Application Fields and Product Features

Liquid silicone encapsulation injection molding: Due to its excellent material properties, liquid silicone encapsulation injection molding technology is widely used in automotive components, electronic communication equipment, industrial seals, household appliance components, medical products and other fields. These products often require good sealing, temperature resistance, aging resistance, and biocompatibility. For example, products such as liquid silicone bottle nipples and liquid silicone buttons are not only safe and non-toxic, but also do not deform or fade after long-term use, making them popular among consumers.

Injection molding: Injection molding technology is widely used in various fields such as daily necessities, packaging materials, building materials, etc. due to its low cost and high production efficiency. There is a wide variety of products produced by injection molding, ranging from simple plastic cup lids to complex automotive parts, covering almost all fields that require plastic products. However, injection molded products are usually inferior to liquid silicone products in terms of temperature resistance, aging resistance, and biocompatibility.

4、 Summary

There are significant differences between the liquid silicone encapsulation injection molding process and injection molding in terms of material properties, process, application areas, and product characteristics. The choice of molding technology depends on factors such as the specific product requirements, production efficiency, and cost control. With the advancement of technology and the continuous development of the market, both molding technologies will continue to leverage their unique advantages to provide better products and services for various industries.

In practical applications, liquid silicone encapsulation injection molding technology has shown great potential in high-end products and special fields due to its unique material characteristics and process advantages. Injection molding technology, with its advantages of low cost and high efficiency, plays an irreplaceable role in daily life and industrial production. In the future, with the continuous innovation and upgrading of technology, these two molding technologies are expected to achieve cross fusion and complementary development in more fields.