Injection molding One compression molding is a technique in which a certain volume (60%-70%) of molten plastic is injected into an open cavity, and then the mold is closed, the melt is melted, the cavity is filled, and the optical lens is molded. When molding, the mold is not closed first, because the mold core part is provided with a step. When the melt is injected into the cavity, it will not vent; when the melt is injected, the second closed by a dedicated closed-die piston The mold, the melt flows again and is compacted. The principle is shown in Figure 1-4.
Injection molding a compression molding application: thin-walled products, products between optical media and lenses, disc gate round products (wheel covers, optical discs), glass fiber reinforced plastic products.
High speed low pressure injection molding
The difference between high-speed low-pressure injection molding and conventional injection molding is that conventional injection molding controls the injection rate during the injection process, while high-speed low-pressure injection molding controls the injection pressure during the injection process, and the injection pressure is constant. In the high-speed low-pressure injection molding process, the injection rate is changed, and the injection is started at a very high rate. As the injection time is extended, the injection rate is gradually reduced to eliminate the stress in the product and ensure the dimensional accuracy of the product. The melt is subjected to very low pressure during high speed injection. The drilling degree is also low. The viscous flow characteristics of the melt are easy to control. Due to constant pressure injection, the high speed low pressure injection molding machine has a special hydraulic system. A multi-chamber hydraulic injection system is currently used.
Most current design projects focus on combining low pressure injection with reinjection of POM plastic molding. For example, the molding of the automobile door trim panel is to put the textile or non-woven fabric into the mold, and then directly inject the melt into the mold.
Alternating injection molding
Alternating injection molding is the change in the size and direction of the flow orientation of the melt in conventional injection molding, thereby improving certain mechanical properties of complex articles. The mold wall is moved during the filling and holding phase, such as moving the mold wall direction perpendicular to the parting line, rotating or sliding type steep wall.
Fuse core forming
The difference between fuse core forming and conventional injection molding lies in the structure of the core. This type of core cannot be removed in the mold. It cannot be mechanically extracted out of the mold. It can only be melted by inductance to heat (such as tin-tough alloy with melting point of 138 Â°C and tin-lead alloy, etc.) or It is washed off in the secondary processing (soluble acrylic resin). The thermal properties of the core and the cavity material are the key to the core forming technology. Core material can be polymer, low melting point metal alloy (tin -
Secret, tin one lead) and so on. The polymer acts as a barrier to the wall, so the skin of the product is very thin. Because the metal acts as a heat sink, the skin of the product is very thick. The selection of appropriate materials can reduce or eliminate warpage caused by defects in the product.
The fuse forming technology is applied to pipe clamps, pump casings (pump propulsion wheels, centrifugal hot water pumps), sports goods (post-ball handles), large parts of automobiles (such as pumps, intake manifolds), spacecraft oil pumps and other products.
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Jinan Xintai Aluminum Industry Co., Ltd , https://www.jinanxintailvye.com