LSR Injection Molding

Mar. 07, 2023

1. What is LSR injection molding?

LSR injection molding is liquid silicone rubber injection molding, also known as injection molding (LIM molding or Liquid injection molding), mainly uses liquid silicone (A agent + B agent + C agent colorant) material dosing device to control the ratio of A agent and B agent to 1:1, then fully mixes it through a static mixer, injects it into the injection tube, and then proceeds to LSR injection molding production.

LSR Injection Molding


2. What is the principle of LSR injection molding?

Injection molding of liquid silicone is most commonly used by injection molding machines, we call it LSR injection molding. Which is used platinum as a catalyst to quickly react and solidify the liquid materials of components A and B, a large number of repetitive and stable production can be carried out through multi-cavity molds. If some products are designed with color, it can be equipped with a color adding pump group and a color metering device equipped with color pigments. The general LSR injection molding is under the mold temperature of 110-130 ℃, after 150-250 seconds (the molding time will change with the thickness, size and material of the product), triggering a chemical reaction to make the silicone material cure. Shape the final product.


LSR Injection Molding

3. What are the advantages of LSR injection molding?

1) High product precision

2) One-time molding can be automated and the output is high

3) Save manpower and electricity

4) No waste

5) The operator's working conditions are simpler, more comfortable and more efficient

4. Which products are suitable for LSR injection molding?

1) Products with high demand, high precision requirements, and urgent delivery time are all very suitable for LSR injection molding.

2) The raw material of liquid silicone rubber has high transparency, which is very suitable for use in optical equipment.

3) Due to the high fluidity of liquid silicone itself, it can completely fill the entire mold, and the whole process is airtight, which can ensure the cleanliness of the product, so which is suitable for food utensils and human invasive medical equipment that require high cleaning.

LSR Injection Molding


5. What is the production process of LSR injection molding?

Step 1: Mold Cleaning and Liquid Injection Molding

Step 2: quality inspection

Step 3: secondary vulcanization

Step 4: Quality Inspection

Step 5: Dust-free packaging for delivery


6. What problems will occur in LSR injection molding? What is the solution?

Problem: Gas encapsulation or adhesive burnt

When the mold is empty, if the mold is closed, air will be trapped in the cavity. When performing injection filling, with the injection of liquid silica gel, the air in the mold cavity space is first squeezed. Due to the low viscosity of liquid silica gel, the filling in the mold cavity is very fast. If during the rapid filling process, the air in the cavity is not fully exhausted in time, or even wrapped in the melt, which will cause the problem of gas encapsulation (that is, we often say trapped air, air bubbles, lack of material), or high-pressure gas at the end of the flow will cause melting. Glue burning phenomenon.


Solution 1: Vacuum the mold cavity

The most effective way to remove the trapped air in the cavity is to forcibly extract the trapped air in the cavity by vacuuming the cavity during each injection molding cycle.


Solution 2: Adjust the clamping force of the mold

Another successfully method is to adjust the clamping force of the mold to achieve the effect of exhaust. When forming, the liquid silicone is filled when the mold is clamped under low pressure, but attention should be paid to avoid the liquid silicone from escaping and forming burrs. When the filling reaches about 90%~95% of the mold cavity, the mold can be converted to high-pressure clamping conditions.

LSR Injection Molding


LSR injection molding is a relatively unique processing technology, and the demand for LSR injection molding products in the market is also increasing. Hopewell is good at LSR injection molding technology, if you are interested in LSR injection molding, please contact us, thank you.

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