National Molding

The Most Popular Types Of Plastic Injection Molding Gates

You may not be familiar with plastic injection molding and we don’t blame you for that. It is just one of the technical terms when it comes to manufacturing plastic and plastic products. It is actually described as a cavity through which liquefied plastic is introduced inside the plastic injection mold. The size and type of the molding gate plays a very vital role in the entire process of injection molding.

What are the types of gates for plastic injection molding?

There are actually two types of injection molded plastic. These are the automatically trimmed and manually trimmed gates. This type of gates requires a controller in each cycle to isolate the pieces from the runners in a manual fashion. It is the preferred gate when the gate is too big to be automatically clipped by the machine, materials that are shear-sensitive cannot be exposed to increased shear rates, and when designs require concurrent distribution of flow in a wide front.

Automatically trimmed gates on the other hand include characteristics in the component to break the gates when the component opens to expel the part. This type of gate is used for reducing cost of manufacturing, bypass gate removal as a second option, reduce scars on components, and keeping a consistent revolution times for all the components of a plastic injection mold.

What are the generally known gate designs?

Plastic manufacturers always give a big emphasis on the gate design when choosing the best gate type for your operation on the injection molding. These are the typical gate designs.

The Sprue or Direct Gate is a hand-operated gate that is intended for isolated cavity injection molded plastic of big cylindrical components that need well-proportioned filling. It is the type of gates that is very easy to design. It also requires minimal maintenance and cost. Components manufactured through this design are commonly high in strength and exposed to minimal stress but it leaves a big scar at the point of connection.

The Hot Tip Gate is the widely-used among plastic injection molding gates that require hot runners. It is commonly found at the tip of the component instead of the parting edge and is excellent for conical or spherical shapes where consistent flow is needed. It leaves a little elevated nub on the exterior of the component. These gates are require systems for hot runners only, so this would mean that plastic is placed inside the mold by a heated spout then cooled to the appropriate shape and thickness inside the mold.

The Sub Gate is the sole gate in plastic injection mold that is automatically trimmed. Pins that eject the components are needed in this type of gates. It is commonly used by plastic manufacturers and has numerous variations like the tunnel gate or banana gate when it comes to injection molded plastic. This gate will permit you to gate away from the separation line, offering you more adaptability to put the gate in the most preferable location on the component on your plastic injection molding. This gate gives a scar with the size of a pin on the component as well.

If you are looking for the most widely-used gate design, the Edge Gate makes it to number one among plastic manufacturers that do injection molded plastic. True to its name, the gate is placed at the edge of the component and is excellent for flat components. It is optimal for production of medium to thick sections and can be utilized on two plate tools that are multi-cavity. A prominent scar can be noticed at the parting line.