Liquid silicone rubber (LSR) injection molding is a process that first mixes two compounds, then injects and cures the mixture with heat inside a mold to mass-produce flexible, durable, complex, and precise silicone rubber parts.
LSR injection molding is widely used across industries, including automotive, healthcare, general industry, baby care, consumer goods, and electronics. These industries benefit from more efficient, cost-effective production with easily moldable liquid silicone rubber.
How Does the Liquid Silicone Injection Molding Process Work?
The LSR injection molding process involves pressing LSR into the mold cavity, where it quickly solidifies into its final shape. Here’s a step-by-step breakdown:
Step 1: Create the LSR Injection Mold
For the LSR injection molding process, the mold must withstand high temperatures. The finished mold is then placed into a specialized LSR injection molding machine.
Step 2: Prepare the Material
The operator prepares uncured liquid silicone in a container connected to a silicone pump (link attached). This is the main component, typically provided as two parts, A and B. Before the material enters the static mixer, the two compounds are mixed at a 1:1 ratio, with optional colorants or additives added to improve hardness, durability, and heat resistance.
Step 3: Inject Material into the Mold
The heated LSR material is injected into the mold cavity under high pressure through a nozzle. Once the mold cavities are filled, the material takes on the mold’s shape. The mold determines the shape of the silicone rubber products, and injecting the LSR mixture into the mold cavity under high pressure and controlled temperature ensures even filling of all details.
Step 4: Curing Process
Once the mold is filled, it is heated to a specific temperature to initiate the chemical reaction that begins the vulcanization process. This process transforms the liquid silicone rubber into solid silicone rubber. The size and complexity of the parts or products determine the curing time.
Step 5: Cooling and Mold Removal
After sufficient cooling, the LSR products must be removed from the mold. This is usually achieved with automated systems.
Step 6: Post-Molding Operations
Secondary operations after injection molding may be required, including demolding and separating the parts. Generally, these secondary processes are conducted after the injection molding is complete. They can include various tasks such as cutting, printing, marking, assembling, post-processing, etc.
Liquid silicone rubber injection molding is a flexible and efficient manufacturing process, offering several advantages over traditional molding techniques. Its design flexibility, high precision, and consistency make it suitable for various applications across multiple industries. This process is an ideal choice for mass production and products with complex shapes.
For more detailed consultation, give us a call at 0708.141.698 – Head Tech is happy to provide you with specific advice on selecting the right vulcanizing machine for your needs!
