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The design of the gate
by：CSSSLD
2021-01-23
For small and medium-sized plastic injection molding processing mode has been widely used in the form of a multi-cavity mould, the design should try to ensure that all of the cavity and at the same time receive uniform filling and forming.
Generally in the shape of plastic parts and mould structure permits, should be the ends of the mainstream way to various cavity equals the growth degree of distributary channel design, shape and cross section in the form of the same size.
But for mould cavity number, is composed of multi-stage distributary channel, flow length and bending, large in the resistance of plastics melt and pouring system setting material.
high surface quality and mechanical performance requirements of cylindrical parts, appropriate USES disc, spokes and claw gate. For ordinary plastic parts widely used side gate or latent type gate. For oversize parts by forming a very large area USES the multipoint feeding and USES the side gate, or gate. High surface quality requirement of foreign small and medium-sized plastic parts, can use point gate and latent type gate, some point gate also designed around a bit pattern to cover gate. In general, form of gate and plastic varieties. The size of the gate section to calculate, shear rate basic to meet the requirements.
in determining the gate location of large plastic parts, plastic melt the allowed maximum flow should also be considered distance ratio. Maximum flow ratio is refers to the maximum length of the melt in the cavity flow with the corresponding thickness ratio of the cavity. That is when the cavity thickness increases, the melt flow can reach by distance also grow some. If the calculated flow ratio is greater than this value, it is need to change the gate location or increasing the wall thickness of plastic parts, or multi gate way to reduce the flow ratio.
the mold design, gate location and size is strict, after the preliminary test also need to further modify the gate size, no matter adopt what kind of gate, open position on the plastic molding performance and its impact on the quality, so the rational selection of open gate position is an important link in improving quality, at the same time different gate location of mold structure. All in all to plastic parts with good performance and appearance, must seriously consider the choice of gate location.
gate should be open in the plastic parts wall thickness is the most big, make the melt flow from thick wall to thin wall, and keep the process is identical in all parts of the gate to the cavity. Avoid gate in injection and peristalsis, and generate ripples in the filling process. Consider molecular orientation effect of gate location should be located in parts of the main stress direction, because along the flow direction of the mechanical properties than in other directions, especially with the filler reinforced plastic, this feature is more obvious.
some gate shoulds not be too small, plastic injection molding processing, such as some wall thickness must be more than two times in the process of injection molding pressure, in order to meet the requirements of plastic parts, gate starts to cause hardening of gate place, feeding difficulties caused by the plastic pieces of defects. The determination of concrete gate section size, according to different forms of gate and plastic pieces of data to determine the size according to the empirical formula and experience. Large, deep cavity plastic parts, appropriate USES direct gate.
should consider when choosing gate location to plastic parts size request, because the plastic gate mold filling, the flow direction and perpendicular to the flow direction of contraction is not the same, so want to consider the direction of the deformation and shrinkage. In a wide position is selected, should be approved by instructor, or with computer simulation of the flow of plastic melt ininjection mould, to make sure the location of the gate is correct, also note gate's influence on the appearance quality.
more excellent articles: the design of gating system, directly click.
http://www。 csssld。 cn//html/2017/Info_0615/605。 HTML
nantong on suye's official website: http://www. csssld。 Cn / /
more wonderful articles, immediately search: changshu da plastic products factory smoothly
high surface quality and mechanical performance requirements of cylindrical parts, appropriate USES disc, spokes and claw gate. For ordinary plastic parts widely used side gate or latent type gate. For oversize parts by forming a very large area USES the multipoint feeding and USES the side gate, or gate. High surface quality requirement of foreign small and medium-sized plastic parts, can use point gate and latent type gate, some point gate also designed around a bit pattern to cover gate. In general, form of gate and plastic varieties. The size of the gate section to calculate, shear rate basic to meet the requirements.
in determining the gate location of large plastic parts, plastic melt the allowed maximum flow should also be considered distance ratio. Maximum flow ratio is refers to the maximum length of the melt in the cavity flow with the corresponding thickness ratio of the cavity. That is when the cavity thickness increases, the melt flow can reach by distance also grow some. If the calculated flow ratio is greater than this value, it is need to change the gate location or increasing the wall thickness of plastic parts, or multi gate way to reduce the flow ratio.
the mold design, gate location and size is strict, after the preliminary test also need to further modify the gate size, no matter adopt what kind of gate, open position on the plastic molding performance and its impact on the quality, so the rational selection of open gate position is an important link in improving quality, at the same time different gate location of mold structure. All in all to plastic parts with good performance and appearance, must seriously consider the choice of gate location.
gate should be open in the plastic parts wall thickness is the most big, make the melt flow from thick wall to thin wall, and keep the process is identical in all parts of the gate to the cavity. Avoid gate in injection and peristalsis, and generate ripples in the filling process. Consider molecular orientation effect of gate location should be located in parts of the main stress direction, because along the flow direction of the mechanical properties than in other directions, especially with the filler reinforced plastic, this feature is more obvious.
some gate shoulds not be too small, plastic injection molding processing, such as some wall thickness must be more than two times in the process of injection molding pressure, in order to meet the requirements of plastic parts, gate starts to cause hardening of gate place, feeding difficulties caused by the plastic pieces of defects. The determination of concrete gate section size, according to different forms of gate and plastic pieces of data to determine the size according to the empirical formula and experience. Large, deep cavity plastic parts, appropriate USES direct gate.
should consider when choosing gate location to plastic parts size request, because the plastic gate mold filling, the flow direction and perpendicular to the flow direction of contraction is not the same, so want to consider the direction of the deformation and shrinkage. In a wide position is selected, should be approved by instructor, or with computer simulation of the flow of plastic melt ininjection mould, to make sure the location of the gate is correct, also note gate's influence on the appearance quality.
more excellent articles: the design of gating system, directly click.
http://www。 csssld。 cn//html/2017/Info_0615/605。 HTML
nantong on suye's official website: http://www. csssld。 Cn / /
more wonderful articles, immediately search: changshu da plastic products factory smoothly
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