Structural foam molding

Structural foam molding is a modified version injection where conventional molding plastic products consist of a dense outer surface of the skin that surrounds the inside (foam). This process is suitable for large-scale production, the product is relatively thick. Foam cores are produced from this process is suitable for bending applications. If the skin has the highest tensile strength and compressive stress, then the neutral axis of the work on the weaker parts of the inner foam. This process offers several advantages from the manufacturing process because it is able to produce products that are complex and have a low voltage so that the tendency for reduced bending or distorted. Then the clamping force is required of this process is lower than conventional injection molding process. This process is widely used for the production of large-sized plastic such as engine housings, chassis, computer housings, bin-bin storage, pallets and others. Polymers are often used for this process is the HOPE, PP, ABS and PC. Resins used in the Low Pressure is applied to this process consists of a small amount of blowing or foaming agent, this type of Chemical Blowing Agent (CBA) decomposition temperatures approaching the temperature of the resin. During the CBA process is decomposed in a large volume of gas as the beginning of a foaming process. Then injected into the cavity short shot. The skin is formed when the gas pressure near the surface of the collapse due to the mold surface. Furthermore, the gas spreads pressing short shot to complete filling cavity. After filling the gas continued to press with the uniform in all directions, pressing the dense skin on the mold surface, effectively also eliminate sink marks. Compared with the conventional injection process, voltage and much reduced shrinkage due to pressure on the cavity is relatively uniform. Before the ejection process must be ensured that the product starts cold and dense. Besides the advantages mentioned above there are a number of disadvantages when compared with conventional injection molding process, namely because the thickness of the walls are made then the cycle time achieved the longer, the consumption of the material also becomes more and more. For this type of process better position the gate at the thinnest part, is to facilitate filling the cavity thick sections. Unlike in conventional injection molding process on the premature solidification of a thin section of a thicker section and the gate does not occur. (Bid / multiple sources)