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Precautions For Plastic Parts Manufacturing
Jul 04, 2017

             Plastic processing shrinkage is one of the most common problems in plastics processing, and it is a thorny problem to shrink the plastic products with high surface quality. Therefore, with the continuous improvement of plastic processing technology to minimize the shrinkage of plastic processing, improve product quality is imperative Plastic Parts Manufacturing

             In a thicker part of plastic processing plastic parts, such as ribs or bumps, the contraction is more severe than that of adjacent locations, because the cooling rate of the thicker area is much slower than the surrounding area. The cooling speed is different, which leads to the formation of a depression at the junction surface, which is known as the shrinkage mark. This defect severely restricts the design and molding of plastic products, especially for large, thick-walled products such as the bevel chassis and display housings for televisions. In fact, for household appliances This kind of stringent requirements of products must eliminate shrinkage, and for toys and other surface quality requirements are not high products allow plastic processing shrink marks exist.Plastic Parts Manufacturing

            There may be one or more reasons for forming shrinkage marks in plastic processing, including machining methods, geometrical shapes of components, selection of materials, and die design. Geometric shapes and material choices are usually determined by the raw material supplier and are not easily changed. But there are a lot of mold design factors that may affect the plastic processing contract. The design of cooling runner, gate type and gate size may produce many effects. For example, a small gate, such as a tubular gate, cools much faster than a cone-shaped gate. Premature cooling at the gate reduces the filling time in the cavity, thereby increasing the likelihood of contraction marks. For molding workers, adjusting the processing conditions is a way to solve the problem of plastic shrinkage. Filling pressure and time significantly affect shrinkage. After the parts are filled, the excess material continues to be filled into the cavity to compensate the material for contraction. The filling phase is too short to cause a contraction to increase, resulting in more or greater contraction marks. This solution to the plastic shrinkage method itself may not reduce the shrinkage to a satisfactory level, but the molding workers can adjust the filling conditions to improve the contraction marks.Plastic Parts Manufacturing