A Simple Guide to Injection Mold Gate Design

Injection mold making technology makes up for a huge chunk of manufacturing around the world. Items that are used for the day-to-day lives of people are made using injection molding as it is faster and cheaper compared to other processes. But how exactly are they made? One main component of the whole process is the mold gate. We are going to explore what a mold gate is, why it is important for injection molding design, and the things one has to consider when selecting one. So stick to the end if you have an interest in knowing more about injection molding.

What Is a Gate in the Injection Mould?

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This is a small cavity or opening designed into an injection molding cauldron that allows the hot plastic or molten metal to be injected into the space inside for molding whatever item one wishes to. The main purpose it serves is to cut off the extension left behind once the injection is done to give the item inside a complete shape. Without a gate, the injection would solidify while still being attached to the injection nozzle, and this would interfere with the design.

Gate designs come in three types that include the following.

Edge Gate: This is the most common of all gates and is located at the edge of the mold. It is best suited for flat parts, and it tends to leave a scar on the final product.

Hot Tip Gate: This is designed for use with hot runners. It is located on the top part of the molding cauldron and is best suited for radial objects of uniform thickness.

Sub Gate: This is a gate that uses pins to shear runners off. They are best when it comes to producing items that don’t have scars, and it lowers the cost of production.

Why Gate Design Is Important to Injection Molding

Getting the right mould design will smoothen out a lot of manufacturing issues that many people are forced to deal with. One thing about injection mold tools is that they are hard to design and make, but once they are set in stone, then manufacturing becomes easy as the gates can be used over and over again. So why is gate design such a big deal?

It determines the final shape of the product in question; therefore, the gate design has to be right, or it will affect everything that comes off the assembly line.
It is the gateway that controls how much molten plastic is injected into the mold; this means it has the power to either make or break the mold. If you make it too big, the shearing of the plastic will be hard; if you make it too small, the mold will be unable to fill completely.

Injection Molding Gate Design Factors

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There are three main factors that one has to consider when dealing with injection molding gates. Each of these factors affects the end product in a unique way, and messing up on this part can render the entire production a waste if caution is not observed. These factors include the following.

Mold Gate Size: There has to be a balance between filling the mold with the exact amount of molten plastic and ensuring that the smallest runner possible is achieved. Smaller gates provide smoother appearances, but they take too long to fill and considering how fast plastic solidifies, this could affect the structural integrity of the product.
Mold Gate Location: The ideal location of a gate should be in the deepest cross-section that will provide the best material flow and cut down on the chances of voids forming up. The gate should also be located in a place where stress and distortions are minimized.
Number of Mold Gates: If you are dealing with a larger mold, then it is necessary to have several mold gates to deal with all the issues that may come up. The gates help control the amount of plastic being injected into the mold by acting as the bottlenecks for the resin.

Tips for Injection Mold Gate Design

For mold gate design, there are some tips you have to consider to ensure that the design comes out exactly as you want and serves your purpose. The following should help you along the way.

Avoid obstructions like pins, cores, and sidewalls that may end up impeding the flow of plastic being injected into the mold. Keep gates away from any form of obstructions.
Ensure that the area around the mold gate is well strengthened as it will be subject to a lot of pressure and stress. It must be able to withstand all that without collapsing.
Consider adding at least two gates for proper filling. If you feel like a second gate is warranted, then add one by all means to enhance the quality of the end product.
Prioritize function over aesthetics when designing the gate mold. You can always work on the appearance later, but if the functionality is flawed, then it becomes hard.

Conclusion

Designing an injection mold gate is a delicate matter that should be approached with caution as it will determine the end result for any product that comes off the assembly line. Ensure you use the services of a qualified engineer for the best,to consider results. For more information on injection molding gates and professional plastic injection molding service, check out our website and have all your questions answered.