What are the advantages of water-assisted injection molding technology compared with gas-assisted injection molding technology?

During injection molding, gas or superheated water can be injected into the cavity almost simultaneously with the plastic melt. At this time, the plastic melt is coated with gas or superheated water, and the molded plastic product has a sandwich structure. After the plastic part is shaped, the gas or water can be released to release. Such products have the advantages of saving materials, small shrinkage, good appearance and good rigidity. What are the advantages of water-assisted injection over gas-assisted injection molding? Let's first take a look at gas-assisted and water-assisted injection molding and their respective advantages.

Gas-assisted injection molding (GAIM) technology

Gas-assisted injection molding (GAIM): refers to the injection of high-pressure inert gas when the plastic is properly filled into the cavity (90%~99%), the gas pushes the molten plastic to continue filling the cavity, and the gas pressure is used to replace the plastic protection. An emerging injection molding technology for the compression process.

Advantages of gas-assisted injection molding (GAIM):

(1) Reduce residual stress and reduce warpage problems;

(2) Eliminate dent marks;

(3) Reduce the clamping force;

(4) Reduce the length of the runner;

(5) Save materials;

(6) Shorten the production cycle time;

(7) Extend the life of the mold;

(8) Reduce the mechanical loss of the injection molding machine;

Application of gas-assisted injection molding (GAIM):

Gas-assisted injection molding (GAIM) is mainly used to produce tubular and rod-shaped products, plate-shaped products, and complex products with uneven thickness and large thickness changes. The typical product is the TV shell.

Water-assisted injection molding (WAIM) technology

Water-assisted injection molding (WAIM): An auxiliary injection molding technology developed on the basis of GAIM. Its principle and process are similar to those of GAIM. WAIM uses water instead of GAIM's N2 as a medium for evacuating, penetrating the melt and transferring pressure.

Advantages of water-assisted injection molding (WAIM):

Compared with gas-assisted injection molding, water-assisted injection molding (WAIM) also has the following advantages:

(1) The thermal conductivity and heat capacity of water are much larger than that of N2, so the product cooling time is short, which can shorten the molding cycle;

(2) Water is cheaper than N2 and can be recycled;

(3) The water is incompressible, the finger effect is not easy to appear, and the wall thickness of the product is relatively uniform;

(4) Gas is easy to penetrate or dissolve into the melt to make the inner wall of the product rough, and bubbles are generated on the inner wall, while water is not easy to penetrate or dissolve into the melt, so products with smooth inner walls can be produced.