Injection mold ejector pin

author: Universe plastic

2024-01-13

What is an injection mold ejector pin?

The injection mold ejector pin is one of the important components in the plastic ejection system of the injection mold.

Injection mold ejector pins are usually slender and straight in shape. Injection mold ejector pins play an important role in automated injection molding production operations.

The function of injection mold ejector pin

In the production of automated injection molding operations, equipment is required to automatically remove the cooled plastic parts from the injection mold cavity. The function of the injection mold ejector pin is to eject the cooled injection molded parts from the mold and drop them into the collection frame by penetrating the mold cavity.

Injection mold ejector pins can bring the following benefits to injection molding production:

1. After the plastic parts are cooled, the finished product is automatically ejected and the mold is immediately closed to enter new injection molding production, which significantly improves the production efficiency of injection molding.

2. Through the automatic ejection of the equipment, the manual removal operation is eliminated and the hidden dangers of production safety are reduced.

Injection mold ejector pin types

There are many types of injection mold ejector pins used in injection molding manufacturing, the following are the most common ones:

Through-hard ejector pins: These ejector pins are heat treated to ensure the hardness of the ejector pins. Through-hard ejector pins can withstand operating temperatures up to 200°C and are best suited for plastic ejection systems within molds.

Case-hardened ejector pins: Also known as nitrided H13 ejector pins, they are harder than through-hardened ejector pins and are suitable for use in die-cast ejection systems in molds. Case hardened pins are nitrided to 65 – 70 HRC and can withstand temperatures above 200°C.

Black Ejectors: The black ejectors are treated to be self-lubricating and can withstand temperatures up to 1000°C. It is an expensive ejector pin suitable for ejection systems in custom automotive plastic product molds.

In addition to different types, there are also a variety of injection mold ejector pin shapes.

Injection mold ejector pin design

In the design process of the injection mold, the appropriate size, shape and position of the injection mold ejector pin is very important. The following points need to be paid attention to:

1. The thimble is usually made of metal materials, such as steel, copper, aluminum, etc. When choosing materials, consider the strength and wear resistance of the ejector pin.

2. The ejection force of the injection mold ejector should be as balanced as possible, and the number of ejector pins with larger demoulding force required for complex structural parts should be increased.

3. The ejector pin of the injection mold should be set in effective parts, such as bone positions, pillar positions, steps, inserts and other structurally complex parts. One thing to note is to avoid setting on bevels or using flat thimbles on bevels. In addition, avoid sharp steel, thick steel, especially the top surface of the ejector pin from touching the surface of the front mold.

4. Consider the distance between the injection mold ejector pin and the water channel to avoid affecting the processing of the water channel and water leakage.

5. Consider the appearance requirements. If there are products with appearance requirements, avoid arranging ejector pins on the appearance surface.

6. For transparent products, the thimble should not be placed in areas that require light transmission.

Injection mold ejection pin installation

The installation of the ejector pin of the injection mold is also an important link. The installation process of the ejection system of the injection mold is as follows:

1. Set up the installation box: The installation box is set at the bottom of the injection molding machine workbench.

2. Installation of the lower mold: The lower mold is installed on the workbench.

3. Installation of the top plate: The top plate is installed inside the upper mold.

4. Installation of ejector pins: Multiple ejector pins are evenly distributed at equal distances. The upper part of the ejector pin passes through the lower mold and is connected to the bottom of the ejector plate. The lower part of the ejector pin passes through the mounting box and is connected to the mounting plate.

5. Installation of the mounting plate: There are feet at the bottom of the mounting plate, and the slide rails are installed at the bottom of the feet. There is an ejection mechanism underneath the slide rail for pushing the slide.

When installing the ejector pin of the injection mold, it should be noted that the ejector plate consists of two plates, one is the fixed plate and the other is the supporting plate (also called the top plate).

One-stop injection molding customization service

The design and installation of injection mold ejector pins are important and difficult tasks that require experienced injection molding engineers to operate.

If you are looking for a professional and cost-effective injection molding company in China, please contact us at Universe Plastic Factory.

We provide high-quality one-stop injection molding services, including injection mold manufacturing, injection molding product design and production. More than 15 years of insisting on low cost, high quality and on-time delivery.

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