First, the technical principle and technical characteristics of gas assisted injection molding

Gas assisted injection molding technology is an innovative plastic molding technology that arose in Europe in the early 1990s. The main forming principle of this technology is: In the process of filling the plastic melt mold, controlled high-pressure gas (usually nitrogen) is injected into the plastic melt, so as to promote the plastic melt to fill all the mold cavity, and through the hollow airway formed by the high-pressure gas inside the melt to apply pressure to the plastic melt, so as to achieve a one-time production of large wall thickness difference and complex structure of the injection molding parts. Because the position and pressure of gas injection can be flexibly set, it greatly improves the design freedom of injection parts in many industries such as automobiles, home appliances, daily necessities, and is known as another revolutionary technology since the screw injection molding machine in the injection molding industry. jpg" style="height: 345px; width: 500px" />

Advantages of gas-assisted injection molding technology:

(1) Save 10% ~ 50% of materials;

(2) The clamping force is reduced by 30% ~ 70%;

(3) Improve production efficiency by 20% ~ 40%;

(4) Eliminate the shrinkage of products, warping and other defects.

Second, the application range of gas-assisted injection molding technology

Because high-pressure gas is injected into the injection molding parts to form a hollow airway, the gas-assisted injection molding technology has a significant raw material saving effect for rod or rod shaped parts, such as refrigerator/electrical handles, seat armrest and other thick solid injection molding parts. The use of gas-assisted injection molding technology can not only save up to 20%-40% of raw materials, but also achieve excellent surface quality due to the pressure holding effect of high pressure gas from inside to outside. In addition, gas-assisted injection molding technology can also effectively improve the molding dimensional accuracy of large flat panel parts, restrain or eliminate the common warping deformation defects of flat panel parts, such as car door panels, refrigerator trays, automotive interior and exterior trim parts and other flat panel parts using gas-assisted injection molding process, can be reasonable design and use of the reinforcement structure of the parts, The gas channel is set up at the root of the reinforcement, so as to effectively reduce or eliminate the internal stress caused by the difference of section wall thickness, and achieve the purpose of reducing or eliminating warping deformation. With the development of a new generation of TV technology, the trend of large size and planarization of TV continues to improve, and the dimensional accuracy and assembly requirements for the front and back shell injection parts of large screen TV are becoming more and more stringent. The proportion of the front/back shell injection parts of large screen TV above 64cm are produced by gas-assisted injection molding technology. Injection molded parts of various household appliances have become one of the main application areas of gas-assisted injection molding technology.

Third, the development prospects of gas-assisted injection molding technology

Since the gas assisted injection molding technology entered industrial production in the 1990s, it was first introduced by the color TV industry to solve the high-precision molding problem of large-size flat TV shell. Japanese TV manufacturers successfully realized the production of the front shell of the TV housing by using gas-assisted injection molding technology, and then domestic TV manufacturers such as Sichuan Changhong also introduced British gas-assisted injection molding equipment to produce large-size flat TV sets. Major foreign automobile manufacturers are also very concerned about the application of gas-assisted injection molding technology in the automotive industry, such as the United States Ford Company, Japan Mazda Company have developed different models of bumper, instrument panel, glove box and other gas-assisted injection molding parts. In addition, as people's requirements for various consumer electronics products and office/daily supplies continue to become lighter and more portable, technical advantages such as high degree of design integration and good molding quality of gas-assisted injection molding parts will be further promoted and popularized. jpg" style="height: 372px; width: 560px" />

4. Application examples of gas-assisted molding process for automobile injection parts

In order to meet the integrated development requirements of automotive injection molding parts, Delphi Interior and Lighting Systems, an American OEM, has collaborated with GE to develop gas-assisted molding parts for automotive door inner panels (the "Super Plug" program). The plan has achieved the design goal of replacing steel with plastic. The resin and 30% glass fiber materials of the new structural design are used to successfully manufacture the whole interior plate of the car door with large cross section difference and uneven wall thickness distribution (parts thickness ranges from 3mm to 20mm) through gas-assisted injection molding technology. As a result, the original design scheme is replaced by 61 parts assembled from metal materials, which not only greatly reduces the quality of parts, but also does not require subsequent assembly processes and equipment, significantly reducing equipment and labor costs.

Advantages of gas-assisted technology: (1) all components are integrated into one, reducing component and assembly costs; Shrink marks are eliminated, surface quality is improved; (2) The tonnage of injection molding machine is 2600 tons, which is 26% lower than that of traditional injection molding; (3) Quality reduction: front bumper reduced by 37%, rear bumper reduced by 24%.