Because plastic caps have the characteristics of strong plasticity, low density, high specific strength, high bonding strength, high chemical stability, and diverse appearance, they are loved by more and more manufacturers and people. Demand for plastic cap molding parts is increasing, and quality requirements are getting higher and higher. This requires the development of molds for plastic parts, and the level of design and manufacturing must also be higher.
Known volume V plastic or quality W plastic , and because this product is a small-scale production of large-scale plastic parts, comprehensive consideration of productivity and production costs and other factors, as well as the injection machine model selection, initially determined to use a four-cavity symmetry Sexual arrangement. The side gate is determined by the dimensions of the plastic parts and the factors of mechanical processing. It is also called the edge gate . In general , the side gate is set on the parting surface of the mold and fed from the side edge of the product . It can easily adjust the shape of the gate . Its cross-sectional shape is usually rectangular ,
The plastic part will be covered on the punch due to shrinkage during cooling, so the corner from the plastic part will be demoulded.
Considering the degree of consideration, it should be beneficial for the plastic parts to stay on the side of the movable mold to facilitate demoulding. And does not affect the plastic parts and the appearance of shape, as well as dimensional accuracy. The gating system is generally composed of four parts: a main flow path, a runner, a gate, and a cold pocket.
The design of the gating system should ensure the smooth flow of the plastic melt, the process should be as short as possible, to prevent deformation of the core, renovation should be convenient, to prevent deformation and warpage of the product, applicable to the type of plastic materials, cold material hole design is reasonable, Minimize plastic consumption.
The section thickness of the plastic parts is small, so it is not suitable to use the push rod to push out, but the use of push plate is more appropriate. Therefore, it is not appropriate to open a cold pit, so the pull rod adopts the form of a ball buckle. Does not affect the appearance of plastic parts, according to the above parting surface, the runner should adopt a circular cross-section, in the fixed mold plate with a sprue bushing.
According to the external dimensions and quality of plastic parts, the initial values ​​are as follows:
d=4mm D=8mm R=15mm t=4mm
r=2mm l=45~50mm L=40~50mm
Preliminarily estimate the volume of the gating system, V pouring = 6~7cm3 .
Its mass is about: W = V pouring plastic pouring × r = 7 ~ 8g.
S = (n × W + W plastic casting) /0.8=16~17g.
Therefore, choose the injection machine model: XS-Z-30 .
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