What Is Liquid Silicone Injection Molding Process
Liquid Silicone Injection Molding Process is a manufacturing process which running liquid silicone rubber. It is different molding process comparing to the traditional plastic injection molding process. As their raw material is solid as granule, sheet, powdery. So liquid silicone rubber injection molding process will be absolutely different. LSR injection molding process will mainly need a silicone injection molding machine, liquid silicone metering and dosing machine, liquid silicone injection molding mold, and a traditional water-cooling chiller as well to keep the liquid silicone rubber cool and prevent it became cured before injected in the silicone molding mold.
Liquid Silicone Injection Molding Process
Liquid silicone rubber molding process is a rubber injection molding process but have other difference as well. Liquid silicone molding process need a liquid silicone metering and mixing equipment to control two-part component material combined in a ratio 1:1. And then supply to the silicone injection machine`s screw and barrel unit to remix and make the material is fully mixed even. Then the screw accurately injected it to a liquid silicone mold cavity. Then the silicone mold we be heated to a certain temperature to cured the liquid silica to a final solid product.
Please refer to below picture to help you understand the silicone rubber making process:
How to Understand Liquid Silicone Rubber Injection Molding Process
Below we will try to explain the liquid silicone rubber injection molding process step by step.
1st. The silicone material is supplied by 2 different component A & B is the same quantity with buckets (10KG) or drums (100KG). We put the drums on the platform like plunger and fixed it well. The plunger will inject the liquid silicone to the metering and dosing machine`s metering pump. And then the liquid silicone metering pump will pump these two-part silicone component to the mixing joint in 1:1 ratio. For some colored products it will need a colorant feeding unit to feed the color pigment to this joint as well. After all the liquid silica is join here then it will be feed to a static mixer to make it mixed even.
2nd. The first grade mixed silicone material will be supplied to the silicone injection mold machine injection screw and barrel. This liquid silicone material we be remixed again here. Just to ensure it`s fully combined even. The silicone injection moulding machine screw and barrel must keep cooled with the cooled water supplied by a water chiller. Here is one of difference between liquid silicone molding process and other plastic manufacturing processes.
3rd. The mixed liquid silicone is wait for injection when it goes to the head of the silicone machine crew. The injection nozzle is different also, as it is a auto shut-off pin valve nozzle. Just to avoid the liquid silicone getting leak when the nozzle do not keep touching the liquid silicone injection mold. Here have one of different injection molding process as well. The nozzle will left the silica injection mold after injection and pressure hold finish. Because the nozzle must keep cooled to prevent the liquid silica in it. But the silicone injection mold is heated to cured the liquid silicone in the molding mold.
4th. The cooled silicone is injected to the silicone mold. And then the liquid silicone molding mold will be heated and then the liquid silicone will be cured and convert to solid silicone products.
5th. The silicone injection molding mold will be open after the silicone product is injection molded finished. And then the silicone injection molding parts will be ejected by ejector or by auto air-blow ejected or token off with robot arm or human by hand. As liquid silicone injection molding parts is mostly elastic parts, liquid silicone rubber manufacturing process can produce lots of parts that could not produced by normal plastic manufacturing processes. Like products that have small mouth but bigger empty body.
What is the difference between LSR injection molding process and plastic injection molding?
After you learn above explanation of LSR injection molding process, you can easily find below difference between liquid silicone molding process and traditional plastic injection molding process.
Dedicated designed liquid silicone injection nozzle with auto shut-off function and water cooling system
1. The raw materials are in different format. Liquid silicone rubber injection manufacturing process is running liquid material. While normal plastic injection molding process runs solid plastics.
2. Liquid silicone injection moulding process is a process about chemical reaction process. LSR injection molding process needs two-parts compounds combined together and take chemical reaction under the chemical action of platinum catalyst. Silicone rubber molding process is a process that makes liquid silicone material to solid silicone products. Normal plastic injection molding process is solid material to solid products.
3. Liquid silicone injection molding requires components A and B are combined in a 1:1 ratio. Then normal plastic injection molding has no such requirement. Their raw material have a rang ratio for mixing.
4. Liquid silicone rubber manufacturing process need a dedicated silicone metering and dosing machine rather than a traditional material auto-feeder. The silicone metering and dosing equipment is precise and much more expensive than a plastic feeder.
5. Liquid silicone rubber molding process requires keeping raw material cooled before it`s injected to the mold. While plastic injection molding process is keeping raw material heated and melted.
6. Liquid silicone rubber injection molding process need special auto shut-off nozzle to prevent raw material getting leak.
7. Liquid silicone molding process is cold runner to hot runner process. While plastic injection molding process is hot runner to cold runner process.
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LSR Silicone Injection Molding Machine Manufacturer in China
