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How To Design The Gate Of Injection Mold?
Aug 04, 2018

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       Gate of the design and structure of the size of the shape mould, injection process conditions and factors such as plastic parts performance But in terms of basic function, gate section is smaller, shorter length, because only in this way can meet the increasing material flow speed, fast cooling, is advantageous for the plastic pieces of separation and gate mark minimum requirements 

1.The position of the gate needs to meet the requirements of appearance (gate mark, fuse wire) product function requires mold processing requires that the warp deformation gate capacity of the product is not easy to remove the molding process easy to control

Impact on production and function do so decided to injection pressure and clamping force, as well as the product fill not fill full extended shortened can reduce injection pressure and clamping force gate location will affect the holding pressure, holding pressure, holding pressure balance, gate from product loading location (such as bearing) to avoid residual stress, and must consider the exhaust gate location, in order to avoid product wind, don't put product gate weaker or embedded in, to avoid the deviation

       Choose the technique of gate location sprue gate is a cross sectional area of small short groove, used to connect cavity flow and transverse section area is so small, the purpose is to obtain the following results: cavity note soon, gate namely cold after the shuikou easy removal in addition to the nozzle, just leave a little trace of multiple cavity packing reduce packing too much easier to control

Gate location and size of the gate is placed in the thickest place, products from the thickest place into the watering can provide better filling and pressure effect If pressure is insufficient, thinner area will be thick area faster solidification, avoid sudden changes in place, put the gate on thickness in order to avoid the happening of hysteresis phenomenon or short shot possible, from the central product into water, place the gate to the central can provide products such as long my lover, my lover will affect the required injection pressure, the size of the central into water makes the holding pressure evenly in all directions, can avoid the volume of non-uniform shrinkage When plastic flow into the port, plastic near surface heat (cooling) and the first drop of solidificationWhen plastic flow forward again only after the solidification of plastic laminar flow and heat transfer material, because the plastic is low solid plastic forming insulated layer and keep the layer can still flow so, ideally, gate should be set in the cross flow layer position, make the best of plastic flow effect the situation of the most common in circular and hexagonal cross flow. Trapezoidal cross flow way to achieve this effect, however, due to the gate cannot be set up in the middle of the flow channel location decision gate location, should comply with the following principles: cavity injection parts rubber should be average as far as possible;The glue of the injection mold should maintain a uniform and stable flow front at all stages of the injection process.Consideration should be given to possible welds, bubbles, holes, empty positions, insufficient injection and other situations.The operation of the water outlet should be as easy as possible, preferably automatic;Gate location should cooperate with all aspects of the design method of gate and no hard and fast rules, are mostly based on experience, but there are two basic elements must be compromise: gate of this area is very large, and trough the length of the tao is more short more good, in order to reduce the pressure loss plastic through the gate to be narrow, in order to easy cold junction and prevent excess plastic back. Therefore gate in the middle of the flow channel, and its cross section should be as much as possible into a round shape, however, gate switch is usually determined by switch module

The size of gate can be determined by the cross-section area and the length of gate. The following factors can determine the optimum size of gate:Rubber injection mold cavity thickness of flow characteristics of the module of the rubber shoes melting temperature of mould temperature 4 runner balance if you can't get a balanced runner system, can adopt the following runner balance method, draw a injection molding in order to achieve the goal of this method is applicable to a large number of cavity of mould runner balance method has two kinds: change the length of the gate, and the gate of this area in another case, namely cavity have different projection area, gate also need to balanceAt this time, to decide the size of the gate, will be one of the first gate size set, and its corresponding cavity than the ratio of volume, and apply this ratio to the gate and the comparison of the corresponding cavity, can have the size of the gate after the actual test after injection, can complete the balance of gate operation 5. Direct gate, or gate runner direct supply plastic to manufactured goods, sprue adhesion on manufactured goods in two plate mould, gate is usually a one, but in three board mould or the design of the mould of hot flow path, can be more than one beerDisadvantages: in manufactured goods surface shuikou will affect the finished product appearance, size and nozzle seal is pumping fine diameter of nozzle hole 6. Pumping tip Angle of stripping, pumping the length of the nozzle can reduce the fine so gate seal, as long as the pumping tip size change a little. But pumping the diameter of the nozzle by pumping the influence of nozzle diameter, the nozzle to easily, the relationship between the mold ejection Angle can not be less than 3 degrees, so only pumping nozzle length can be shorten, with extended pumping tip can gate choice: gate is the connection part of the runners and cavities were, is also the last part of the feed system of injection moulds, its basic function is:Made from the port to the molten plastic to the fastest speed into the mold cavity is filled, gate cooling closed quickly, prevent the reverse flow of cavity can not cooling plastic PS: (pumping tip in the mold is very important part, melted plastic formation after pumping tip injection mold products, assembly in the middle of the front mould (A)) 7. Summarizes the design of the gate and structure size of shape mould, injection process conditions and factors such as plastic parts performanceBut in terms of basic function, gate section is smaller, shorter length, because only in this way can meet the increasing material flow speed, fast cooling, is advantageous for the plastic pieces of separation and gate mark minimum requirements such as gate design key points can be summarized as follows: 1) the gate opening in the cross-section of the thicker plastic parts, the molten material from the thick sections into thin sections to ensure mold filling completely;2) the choice of gate position should minimize the plastic mold filling process to reduce pressure loss;3) the location of gate should be conducive to the elimination of air in the cavity;4) the gate should not make the melt directly into the cavity, otherwise there will be whirlpool, which will leave the trace of rotating shape on the plastic parts, especially the narrow gate.5) the location of the gate should be selected to prevent the formation of stitching line on the plastic surface, especially for the solid circular ring or cylindrical parts, the cooling material well should be opened at the fusion place of the gate surface;6) the gate position of injection mold with slender core should be far away from the molding core, so that the molding core will not be deformed due to material flow.7) when large or flat plastic parts are formed, compound gate can be adopted to prevent warping deformation and lack of materials;8) the gate should be opened as far as possible without affecting the appearance of the plastic parts, such as the bottom of the edge;9) the size of the gate depends on the size and shape of the plastic parts and the performance of the plastic;10) when designing multiple cavity injection molds, the balance of the gate should be considered in combination with the balance of the flow passage, so as to ensure that the melt is filled uniformly at the same time

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