Design fan gate is similar to the side gate, but width of gate is bigger and has fan-shaped. Used in large size molded product. It permits rapid filling of large parts or fragile section mold area with large entry area. It is used to create uniform flow into wide parts.
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1. Advantages and disadvantages of fan gate.
A. Advantages.
+ Making easy.
+ This ensures a constant and more even plastic flow into the cavity into a wide area at a slow injection speed, minimizing back filling and reducing imperfections and stresses in the part.
+ It can use for sample with big thickness and enables slow injection without freeze-off.
+ It can improve bending of product.
+ Melt velocity will be constant.
+ the entire width is being used for the flow.
+ the pressure is the same across the entire width
B. Disadvantages.
Because fan gate have big cross section, so we need to careful in gate cutting. If cutting isn’t good, sample can be scratch, bending.
2. How to design fan gate?
This picture above is dimension of fan gate.
+ t: wall thickness of product.
+ T: Thickness of gate where connect with a product. It is usually from 0.5~0.8 part thickness.
+ L: Length of gate.
+ W: With of gate.
+ D: Diameter of runner.
Note: when you design fan gate, cross of runner is circle give the best result.
You can read runner design at https://mechanicalengblog.com/plastic-injection-molding-runner-system/
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