Gas assistant injection molding

Application prospect  gas assistant injection molding in china 

Gas-assisted injection molding technology is widely developed in China. Since 1990, as a new type of technology, in order to overcome the limitations of traditional injection molding. The plastic injection engineering community is of general concern. The use of gas-assisted technology, improve product accuracy, surface quality, to solve large size and wall thickness varied deformation of the product. Improve product strength, reduce stress, save plastic materials and greatly simplify mold design. Gas assistant injection molding was widely used in automotive, household appliances, office supplies, household products, and many other fields.

Plastic Injection Molding Second Revolution

It is called the second revolution of the plastic injection molding china industrial. Process simulation of gas-assisted injection molding with CAE software, help us to understand the melt filling in the injection molding process. The gas-assisted filling, gas protection pressure molding process, to avoid the injection melt insufficient.

If the gas pressure is too large, cavitation, blowing wear surface depression occur to determine the melt gate. The gas inlet position, the runner dimensions airway size optimization and airway reasonable arrangement, material selection, process conditions set.  And through the analysis of the calculation results, determine a set of the best program to ensure the test model success. In recent years, we have successfully passed CAE analysis software to assist injection molding of home appliances and automotive parts and achieved good results.

Two Gas-assisted Injection Molding Ways

Gas-assisted injection molding molten resin injection. Gas injection, gas holding pressure, gas recovery, part ejection, and several major steps. The molten resin is injected into the mold cavity through the gate, and then inject a constant pressure of inert gas (usually nitrogen). The resin is produced by the gas pressure and is filled to the various parts of the mold cavity. So that the plastic part to finally form a hollow section while maintaining the full shape. And from the interior of the resin packing, the gas pressure becomes the holding pressure.

Gas emissions occur at the end of the cooling mold. Compared with the conventional injection molding process, a gas-assisted filling stage, and the packing stage holding pressure by air pressure. Holding pressure, can reduce stress and prevent Warp products. Due to the pressure exerted by the gas that can effectively pass, The internal surface of the product can be ensured during the cooling process to compensate for the volume shrinkage. And also to avoid the deformation when part ejection.

Using gas-assisted injection molding is controlled by the amount of plastic to control the injection cavity articles the hollow ratio and the shape of the airway. Gas-assisted injection molding pressure control method and volume control method are two ways.

 gas-assisted for china injection molding and china mold maker technology features

• It is capable of forming wall thickness difference larger products and complex three-dimensional hollow products

Gas-assisted technology into the airway wall thickness at the hollowed design. Thus ensuring the thickness difference the larger molding quality of the products, the use of gas-assisted technology. But also to simplify the structure of the products. Parts due to the large wall thickness difference had to be divided into several parts. Injection molding and then together, forming one gas-assisted technology.

• Injection pressure is low

Gas from the gate to the end of the current to form a continuous flow passage, no pressure loss can be realized in low-pressure injection molding, therefore, the residual stress is smaller parts, warpage deformation is small, dimensionally stable.

• Eliminate sink marks, improve the quality of the product surface

In the gas packing process, the contraction of the plastic secondary penetration by the gas to be compensated, so that the parts will not sag In addition, the use of gas-assisted injection molding, the thicker part of the products can be hollowed out to reduce or even eliminate sink marks.

In addition, to enhance the strength and stiffness, but also save materials, shorten the molding cycle.