Liquid Injection Molding is a process in which a polymer liquid is injected into a mould cavity for a variety of industrial and manufacturing applications

 

Liquid injection molding is used in chemical manufacturing companies, all over the world including regions such as Japan, Germany, and Mexico. Liquid injection molding is an industrial fabrication method used for forming various flexible plastic parts by injection molding polymer liquid into a mold cavity simultaneously. Solid polymer liquid is typically used as the main medium for injection molding; however, thermoset polyimide and ethylene propylene are also used. The plastic models are cooled in an oven before being fed into the mold cavity, and when fully molded, they are extruded out at a higher velocity than normal. In liquid injection molding, the plastic pieces are usually of irregular shapes, which is why it takes the injection process so long to form a model from the liquid. The plastic pieces are also more expensive and difficult to make than most other types of plastic parts.

Liquid injection molding uses two methods for depositing melted plastic components into molds: a cold runner and a heated cavity. The cold runner method involves opening a sealed plastic injection mold in one end and injecting the melted rubber through the mold cavity in another. The heated cavity, on the other hand, incorporates a combination of heat and high pressure to melt the plastics before they are deposited into the molds. Both of these methods have their advantages, with the cold runner type proving most popular among small manufacturers.

A static mixer injects a constant volume of fluid into the mold while simultaneously circulating it through the heated cavities. A high-speed electric motor supplies power to the mixers and heats them to evaporate the liquid at very high temperatures. One of the disadvantages is that the speed of mixing is dependent on the temperature and pressure of the environment, and it can be affected by other outside factors such as humidity, heat, and even wind.

In regions such as German, the abundance of chemical companies has increased liquid injection molding operations. For instance, according to, Germany Works, in 2019, there were around 2900 chemical companies in Germany. Another type of liquid injection molding machine, the low viscosity pump, works with a pump rather than a cavity full of silicone. Instead, the pump forces a constant flow of fluid into the mold through the tubing. The pumping machine also includes a controller that monitors the viscosity of the silicone.