6 Types of Injection Molding Gate & When to Use Them

Injection molding is one of the most popular manufacturing techniques used today. It is used to create a variety of components from small medical devices to large automotive parts. One of the key elements of injection molding is the gate, which is the point through which molten plastic flows into the mold to form the part. There are many different types of gates used in injection molding, each with its advantages and disadvantages. Here we will discuss the six most common types of injection molding gates and when they should be used.

1. Sprue Gate

The sprue gate is the most common type of gate used in injection molding. It is a circular or rectangular opening in the mold that allows the molten plastic to flow into the mold cavity. The sprue gate is the simplest and least expensive type of gate to manufacture, making it ideal for low-cost parts. However, it does have some drawbacks, such as difficulty controlling the flow rate of the material, leading to potential defects in the molded part.

2. Submarine Gate

The submarine gate is similar to the sprue gate, but instead of being located at the top of the mold, it is located at the side. This allows the molten plastic to be injected into the mold from the side. The advantage of this type of gate is that it can control the flow rate of the material better than the sprue gate, resulting in a better quality part. However, it is more expensive to manufacture than a sprue gate and often requires manual intervention to remove the gate after the part is molded.

3. Edge Gate

The edge gate is a type of gate that is located on the edge of the part. This type of gate is ideal for parts that require a high degree of accuracy in the flow rate of the material. The edge gate is also one of the easiest gates to remove after the part is molded, as it is usually located on the edge of the part. The downside of this type of gate is that it can cause defects in the part due to its location.

4. Fan Gate

The fan gate is a type of gate that has multiple openings that fan out from a single point. This type of gate is ideal for parts that require a uniform flow of material throughout the part. The fan gate is also easy to remove after the part is molded, as it usually does not require manual intervention. The downside of this type of gate is that it can cause defects in the part due to its multiple points of injection.

5. Pin Gate

The pin gate is a type of gate that is made up of multiple small openings arranged in a pattern. This type of gate is ideal for parts that require a precise flow of material throughout the part. The pin gate is also easy to remove after the part is molded, as it typically does not require manual intervention. The downside of this type of gate is that it can cause defects in the part due to its multiple points of injection.

6. Hot Tip Gate

The hot tip gate is a type of gate that is heated before injection. This type of gate is ideal for parts that require a precise flow of material throughout the part, as well as parts that require a high degree of accuracy in the flow rate of the material. The hot tip gate is also easy to remove after the part is molded, as it typically does not require manual intervention. The downside of this type of gate is that it can cause defects in the part due to its high temperature.

When to Use Each Type of Gate

The type of gate used in an injection molding process depends on a variety of factors, such as the size and complexity of the part, the type of material being used, and the accuracy required in the part. Generally speaking, the sprue gate is the most common type of gate used for low-cost parts, while the other types of gates are better suited for more complex parts with higher accuracy requirements.

Overall, the choice of gate type depends on the specific needs of the part being produced. Different types of gates offer different advantages and disadvantages, so it is important to choose the right gate for the job. By understanding the various types of gates available and when to use them, you can ensure that your injection molded parts are of the highest quality.

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