Guidelines for Injection Mold Lifter Design

1. Introduction

In injection molding, the lifter is one of the most crucial components. The design and manufacturing precision of lifters directly impact the overall performance of the mold and the quality of the products. This blog will provide a detailed overview of key guidelines for designing lifters in injection molds, including lifter structure types, working principles, and design considerations.

2. What is a Lifter?

A lifter is a mechanism used in the design and manufacturing of molds, typically in plastic injection molds or die-casting molds. It is employed to handle specific shapes or structures within the mold, often utilized for creating internal undercuts or complex features in a product. The purpose of a lifter is to enable the successful ejection of products with these unique shapes from the mold without causing damage to either the product or the mold.

3. The Working Principle of a Lifter

The working principle of a lifter in injection molding involves a specific mechanical movement that is designed to address undercuts or complex features in molded plastic parts. Lifters, sometimes referred to as cam actions, are an essential part of the injection mold.

Here's how they work:

Undercut Resolution: Lifters are primarily used to deal with features like undercuts in a molded part. Undercuts are areas where the part's geometry prevents it from being easily ejected from the mold.

Off-Center Movement: A lifter is typically a movable component within the mold that operates off-center. It's designed to shift or tilt at an angle, which allows it to push against the undercut section of the molded part.

Sequential Action: The lifter's movement is carefully synchronized with the mold's opening and closing sequence. When the mold opens, the lifter moves into action to push against the undercut portion, freeing the molded part from the mold.

Return to Position: After the part is ejected, the lifter returns to its initial position. This movement needs to be precise to ensure the quality of the molded parts and the longevity of the mold itself.

4. Structures and Types of Lifters

A lifter is an important mechanism in mold design and manufacturing, used to handle specific shapes or structures in plastic injection molds or die-casting molds. It is typically employed to create undercuts or complex internal structures in products. The structure and type of this mechanism vary based on application requirements. Below are the structures and types of lifters:

Parallel Lifter: This is a common type of lifter where the lifter's axis of motion is parallel to the mold's opening and closing direction. It is usually used to handle vertical undercuts or complex internal structures.

Cross Lifter: The axis of motion of this lifter type crosses perpendicularly to the mold's opening and closing direction, suitable for more complex undercuts or special structures, providing greater flexibility.

Slide Lifter: In some cases, slides can be combined with lifters to handle specific undercut shapes. Slide lifters can be nested within the mold to achieve more design freedom.

Hydraulic Lifter: This lifter type uses a hydraulic system to control its motion, offering greater power and precision, suitable for high-precision applications.

Pneumatic Lifter: Pneumatic lifters use air pressure for their motion and are suitable for specific environments and applications, providing a clean and oil-free solution.

Each type of lifter structure has its own suitable applications and characteristics. Choosing the appropriate lifter type depends on the shape of the produced parts, mold design requirements, and process needs. Different lifter types can meet various mold design requirements, ensuring successful demolding and the production of high-quality products.

5. Key Considerations of Lifter Design

Lifter design is a critical aspect of mold design, especially in injection molding. Lifters are used to create undercuts in molded parts, allowing them to be removed from the mold. Here are some key considerations for lifter design:

Part Geometry: Analyze the part's geometry to identify areas with undercuts or features that require lifters. Understand the part's size, shape, and complexity.

Undercut Depth and Angle: Determine the depth and angle of the undercut. This information is essential for designing the lifter's shape and movement.

Lifter Type: Choose the appropriate lifter type based on the undercut's characteristics. Common types include straight, angled, and stripper plate lifters.

Material Selection: Select materials for the lifter that are durable and can withstand the molding process's conditions, including temperature and pressure.

Lifter Actuation: Decide on the method of actuation for the lifter, whether it will be actuated by hydraulic cylinders, mechanical action, or other means.

Guiding and Support: Design appropriate guiding and support mechanisms to ensure smooth and accurate movement of the lifter. This prevents binding or misalignment.

Mold Base Design: Integrate the lifter design seamlessly into the mold base. Consider how the lifter will be mounted and anchored within the mold.

Interference and Clearances: Ensure that the lifter's movement does not interfere with other mold components or the part itself. Maintain sufficient clearances.

Cooling and Heating: Incorporate cooling or heating channels into the lifter, if needed, to control temperature and prevent issues like thermal expansion.

6. Conclusion

The injection mold lifter design is an integral part of injection molding processing. Correct lifter design can improve production efficiency, ensure product quality, and reduce production problems. By gaining an in-depth understanding of the work principles and design points of lifter, you can better address the challenges in injection mold design.

If you need more information about injection mold design or have specific questions, please feel free to consult our professional team.