What Is LSR Liquid Silicone Injecton Molding Machine?

2024-01-24

Injection molding, injection moulding, injection molding press, compression molding, compression moulding, hydraulic molding, hot press molding, vulcanization molding, etc.

Here we focus on liquid silicone injection molding, which is LSR Silicone Injection Molding Machine. Injection molding, one-time compression molding is to mix liquid silicone materials A and B in proportion to the injection mold, and then close the mold, through the vacuum cold runner, hydraulic pressure Thermoforming.

Liquid silicone injection molding-compression molding applications: silicone sealing rings, silicone medical supplies, silicone aerospace ship industry auto parts, silicone daily necessities, silicone electronic accessories, silicone children's products, silicone home furnishings, silicone maternal and infant products, silicone toys, silicone jewelry, silicone Trademarks, etc.

Molding process plasticizing system
LSR is a two-component liquid material, divided into component A and component B. The work of the mixer fully mixes component A and component B in a precise 1:1 ratio. And because some products are colored, they are equipped with a color pump set and a color measurement part. A+B components, additives, colors, etc. are fully mixed and then enter the plasticizing system. Different models of hydraulic pressure can be selected according to different products. Jinyu Machinery has different pressure hydraulic model configurations of 30/50/80/100 tons.

Feeding system
One is a two-way pump that can move up and down to feed materials and can maintain pressure very well. Since pumps A and B are connected and synchronously controlled by hydraulic and pneumatic, this form of feeding system is more reliable and accurate. The other is a one-way pump that is a universal type and can only feed materials in a single direction. There are also synchronized single-stage pumps with check valves. There are also metering cylinder systems, which are mainly used in conjunction with single-phase pumps.

Mold design
Hot runner can be used, which wastes less material, has simple design and low cost, and is mostly used for large products.
There can also be cold runners with needle valves, which can realize automation and shorten the cycle.
There are also cold runners without needle valves. Due to the high expansion coefficient of LSR, it will expand when heated and shrink slightly when cooled, so the parts cannot maintain precise side margins in the mold. Therefore, cold runner processing can be used. LSR should maintain a lower temperature and fluidity. The cold runner adopts a closed system. In the injection cycle, the closed system uses a "sealing needle" or "needle valve" in each runner. " to control the accurate measurement of LSR materials.

Because silicone rubber has significant thermal expansion characteristics, the shrinkage rate is 2% to 4% (vulcanization temperature is 150°C), and silicone rubber has the characteristics of compression deformation.

The vulcanization chemical reaction of liquid silicone rubber requires a certain reaction time. Ideal flow, at 2mm diameter, 170cm, flow distance over 100cm. Minimum thickness 1/1000mm, too high mold temperature will cause vulcanization, resulting in flow obstruction. Laminar flow can avoid bubbles, high-speed injection will cause turbulence, the viscosity of the material will change the flow pattern, and turbulence will cause white spots.

Therefore, attention should be paid to the design of the mold: in order to avoid turbulence and jetting, use small injection ports. Use needle-shaped or wing-shaped injection ports. Use T-shaped guide pins instead of cylindrical guide pins, use an injection air gun when demoulding, and add a heat insulation layer/board. Do not use anti-rust agents/oils containing polymerization inhibitors. Generally, toluene, xylene, etc. can be used.

liquid silicone injection molding machine

Dongguan Jinyu Automation Equipment Co., Ltd are specialized in the development and manufacturing of PVC rubber patch machine, Silicone heat press Hydraulic Machine, Garments logo printing machine, silicone Embossing Machine, Silicone Heat Transfer Label Machine, Silicone Dispensing Machine, ect.

With more than 20 years of independent research and development, we have a senior and specialized group. Our company have set up a good reputation within the industry and become the earliest production base of PVC products making machine , Silicone Products Making Machine and other related machines all over the world.

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