Different types of gate for injection molding

The narrow and shallow portion of the runner as it enters the cavity is called the gate.

Runner and Gating Design Handbook: Tools for Successful Injection MoldingIndustrial Design Books)

Listed here are the different types of gate with their characteristics. Sprue and runner are described here.

Side gate: This is the most commonly used gate type and is commonly used for mold structures with 2 or more cavities. It is placed at the side of the plastic product. The gate has to be cut manually by a cutter.

side-gate

Submarine gate: The positioning of this gate is flexible thoughout the sides of the plastic product. It can be placed on the fixed or movable side of the mold but the design has to be thought about carefully so that the product will not be left inside the fixed cavity. The gate automatically cuts itself as the mold opens.

submarine-gate

Fan gate: It is commonly used for large and flat plate products. It is placed at the side of the product – same as the side gate. The gate has to be cut manually by a cutter.

fan-gate

Film gate: Similar to fan gate except that it is commonly used for thin and flat plate products.

film-gate

Pin gate: This is possible for molding multiple cavities or parts. The gate positioning is relatively flexible at the top side of the product. The runner layout is very flexible as well. The mold base structure is complicated because it uses a 3-plate method.

pin-gate

Runner and Gating Design Handbook: Tools for Successful Injection Molding

Banana gate: This is not a very common gate. It is used when the visible surface of the product requires no trace of the gate. The gate automatically cuts itself as the mold opens.

banana-gate

Direct gate: The sprue serves as the gate. It is placed on the top side of the product. The gate has to be cut manually by a cutter. This gate type can only produce one part per shot. The molding cost is low because the material from the runner was ellimenated. The injection pressure was reduced due to direct cavity filling. The simple mold structure makes the mold cost lower.

direct-gate

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About Elito

Mold Design Engineer (contract designer) with more than 13 years experience creating mold designs for high volume manufacturing. Have necessary know-how to produce high quality injection molds at the least processing cost and most timely manner available. Superior problem-solving and time-management abilities. Worked with Japanese mold design team. Proficient with 2D CAD, 3D CAD, MS Office.

32 thoughts on “Different types of gate for injection molding

  1. Hello sir,
    I want to know about vent design with self explanatory images and photo of molded part with the runner gate & vents before trimming.
    Thanks in advance.

    • You can use banana gate if the appearance is critical. That is, if you don not want any markings of gate or ejector pins visible on one side of the product.

    • It could easily be determined in Mold Flow analysis. There are engineering services offering MoldFlow.
      If you have experience with the same material or product you could use the same gating system. Try design by experiment.
      Are you a mold designer or a product designer?

  2. I found what I needed..But I would like to have detailing on gates…This is just fundamental….if it is explained by example will hekp better…Thank You.

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