Liquid silicone rubber (LSR) wrapping around plastic accessory grooves is a high-precision overmolding process specifically used to form silicone components in specific areas (grooves) on hard plastic parts. This is similar to the entire edge wrapping, but the application is more targeted and functional.
1、 Core role
The core of this process is to add functional and experiential soft material properties on top of the structural properties of hard plastic parts.
Accurate and precise functional sealing:
Injecting LSR into specific grooves of plastic parts can form precise liquid silicone sealing gaskets, LSR silicone sealing valves, or partition layers. This is commonly used in areas that require local high-precision waterproofing and dust prevention, such as sensor openings, button key holes, interface covers, and joints of detachable components, rather than sealing the entire product outside.
Create a soft user interaction interface:
The common application is buttons. Covering the button holes and grooves of the hard shell with silicone can form elastic buttons (commonly known as "silicone keys" or "pot pieces") with soft touch, quietness, and feedback force, improving the pressing feel and durability.
Realize non adhesive fixation and shock absorption:
The silicone part wrapped in the groove can be used as a shock-absorbing pad, anti slip pad, or fixed pad. For example, wrapping it in the groove at the bottom of the device can provide anti slip and shock-absorbing effects; Alternatively, it can be wrapped around the buckle structure to increase friction and cushioning, making the connection tighter and less prone to wear.
Forming complex soft structural features:
Soft drainage channels, flexible valves, diaphragms, or protective covers can be directly formed on plastic parts, which cannot be achieved by hard plastics.
2、 Significant advantages
Integrated molding, easy to combine:
The biggest advantage is that silicone and plastic substrates (usually PC, ABS, PC/ABS, Nylon, etc.) form an irreversible and strong bond through chemical and mechanical forces. No need for subsequent assembly, and it also avoids problems such as delamination, aging, and glue overflow that may occur when using glue for bonding, with high reliability.
Design Freedom and Accuracy:
Liquid silicone has excellent fluidity and can fill complex and fine grooves, forming ultra-thin films or complex geometric shapes, which cannot be achieved by solid rubber rings. Allow designers to achieve complex functions in small spaces.
Sealing and cleanliness:
Due to its seamless integrated molding, it can eliminate leakage points. LSR itself has biocompatibility (can be certified by FDA and LFGB), is odorless, and resistant to chemical corrosion, making it very suitable for food related products.
Significantly improve durability:
Silicone has good fatigue resistance and can be repeatedly compressed and deformed millions of times without breaking (such as in button applications). The high and low temperature resistance (-50 ℃~200 ℃), weather resistance, and UV resistance ensure the long-term service life of the product in harsh environments.
High production efficiency and good cost-effectiveness:
Although the mold cost is high, this process is highly automated, integrating the manufacturing and assembly steps of multiple parts (plastic parts+sealing rings+buttons) into one set of molds, saving subsequent manual assembly, management, and inventory costs, making it particularly suitable for large-scale production.
