Injection Mold Slide: Essential Tips for Design and Maintenance

Injection Mold Slide

Injection molding is a prevalent manufacturing technique used to produce complex plastic parts with high accuracy and precision. One key component of the process is the injection mold slide, essential for molding intricate designs with undercuts or protruding features. The function of the slide is critical to ensuring the success of the overall molding operation and producing high-quality parts.

The slide is responsible for moving along with the mold opening in an injection mold. This movement enables the slide to disengage from undercuts or other obstructing features present on the exterior surfaces of the molded plastic part. Due to their essential role in production, injection mold slides are available in various styles, each offering unique advantages and capabilities depending on the specific application requirements.

Key Takeaways

  • Injection molding slides are crucial in molding complex plastic parts with undercuts or protruding features.
  • The slide’s movement within the mold enables disengagement from exterior surfaces, ensuring proper part release.
  • Different types of injection mold slides cater to diverse application requirements and preferences.

Basic Components of Injection Mold Slide

Core and Cavity

The core and cavity are crucial components of an injection mold slide. They form the shape of the desired plastic part when the molten plastic is injected into the mold. The core represents the inside of the part, while the cavity is the outer shape. They ensure the correct component formation and maintain proper alignment during molding.

Slider Body

The slider body is a vital part of a slide mechanism, guiding the sliding movement in the mold. It is built to withstand the forces and pressures exerted during molding, ensuring smooth and precise slide movement. Consistent performance of the slider body guarantees proper alignment and accurate separation of core and cavity.

Guide Pin

Guide pins are essential in slide mechanisms by ensuring accurate alignment and smooth movement. They are designed to withstand wear and tear over time, preventing misalignment during the continuous molding process. Surface nitriding is usually performed to minimize surface wear, prolonging the life of guide pins in the injection mold slide.

Wear Plate

Wear plates protect the slide mechanism from friction and wear caused by moving parts. Positioned near the slider body, guide pin, and other components, the wear plates reduce the direct contact between the moving parts, extending the life of the slide. Like guide pins, wear plates are treated with surface nitriding to enhance their durability.

Angle Pin

The angle pin, or the guide pin, helps control the slide’s movement within the mold. It prevents excessive movement, keeping the components in proper alignment during the injection molding process. Like guide pins, angle pins undergo surface nitriding for increased wear resistance and a longer operational lifespan.

Locking Mechanism

A locking mechanism is employed to securely hold the core and cavity in place during the injection molding process. This proper part formation prevents any unwanted movement of the mold components, allowing for consistent, high-quality output. The locking mechanism is designed to withstand the high pressures and forces exerted on the mold.

Ejector Pin Grease

Ejector pin grease is a lubricant applied to the ejector pins in the mold, ensuring smooth movement during the part ejection phase. Proper application of ejector pin grease helps prevent sticking, galling, or seizing of the ejector pins, maintaining smooth functionality and prolonging the life of the injection mold slide mechanism. Regular maintenance and lubrication are crucial to guarantee optimal performance and longevity of the mold components.

Related Topic ➻ Low-Volume Injection Molding: Efficient Solutions for Small Batches

Injection Molding Process

Mold Opening Direction and Motion

In the injection molding process, we begin with the opening mold action of the injection molding machine. This motion is leveraged to move the guide block and slide relatively. The horizontal direction movement accompanies the mold opening direction, which facilitates the disengagement with the undercut.

Pressure and Temperature Application

The next step in the process entails the application of pressure and temperature. We inject molten plastic into the mold cavity under high pressure and a controlled temperature. Once inside, the plastic takes the shape of the cavity, including any undercuts and intricate surface features present in the cavity.

Forming Surface and Undercuts

Forming a surface and undercuts are crucial aspects of the injection molding process. The forming surface shapes the final product, while undercuts allow for creating complex features on the part. In the case of slides, they assist in disengaging the part from the mold by moving in two directions (mold opening direction and horizontal direction).

Mold Release Direction

We initiate the mold release after the molten plastic has solidified within the mold cavity. Once the mold opens up, the injection molding slide is activated, and the solidified plastic product is ready to be removed. At this stage, the slide usually employs a hydraulic system to push it laterally, releasing the formed plastic part from the mold.

Types of Injection Mold Slides

Injection mold slides are vital components in the injection molding process, as they help release molded plastic parts with undercuts or other complex features that cannot be removed directly from the mold cavity. This section will discuss three types of slides: Wedge Slide, Cam Pin Slide, and Lifter Slide.

Wedge Slide

Wedge slides are injection mold slide that utilizes a wedge-shaped component to move the slide in and out of the mold. This slide has two main parts: the wedge and the slide insert. The wedge is pulled away when the mold is opened, causing the slide insert to retract and release the part. Conversely, when the mold is closed, the wedge slides back, pushing the insert into its original position. Some advantages of wedge slides include the following:

  • Straight movement path, minimizing the chances of misalignment
  • Simplicity in design and construction
  • Cost-effectiveness, as fewer components are required

Cam Pin Slide

Cam Pin Slide, also known as angle pin or horn pin slide, is the most common and versatile type of injection mold slide. The opening of the press drives it, and the action of the angled pin withdrawing from the angled hole moves the slide back. Springs hold the slide in the retracted position. Some benefits of cam pin slides are:

  • Wide range of potential movements due to the variable angle of the pin
  • Compatibility with various mold designs and applications
  • Reliability in performance due to the simple contact mechanism

Lifter Slide

Lifter slides are an alternative solution for releasing parts with undercuts when using a standard slide proves insufficient. They are designed to work with the mold’s opening and closing actions, lifting the part from its undercut during the process. The main components of a lifter slide are the lifter insert and the lifter guide. Some features of lifter slides include:

  • Ability to release complex parts with challenging undercuts
  • Minimizing the need for manual part removal, thus saving time and labor costs
  • Increased precision in part release due to the guided lifting action

In summary, wedge, cam pin, and lifter slides serve different purposes and offer various advantages in injection molding applications. Whether a specific slide type is suitable or preferred depends on the part design, mold construction, and precise manufacturing process requirements.

Related Topic ➻ Trends Driving the Future of Injection Molding Industry

Advantages and Challenges

Benefits of Using Injection Mold Slides

Our injection mold slides provide a fast and efficient method of producing plastic parts, allowing us to create complex shapes quickly. The slider mechanism is powered by hydraulics, ensuring smooth lateral movement, and the process is highly repeatable, resulting in consistent product quality. Additionally, injection molding is cost-effective for high-volume production, making it an attractive option for manufacturing a wide range of parts.

Wear and Tear Management

Managing wear and tear is essential for maintaining the performance of injection mold slides. To minimize wear, we ensure the sliding guide promotes a smooth and stable movement, preventing issues such as sticking or bouncing during the process. This also helps prolong the mold’s service life, leading to a reduction in long-term costs.

Managing Friction

Friction is a common challenge we face when working with injection mold slides. To overcome this, we apply proper lubrication to the slide elements, reducing the chances of any premature wear and ensuring smooth operation. By keeping friction in check, we enhance the overall efficiency and productivity of the injection molding process.


Preventing rust is a crucial aspect of maintaining the longevity and efficiency of our injection mold slides. We use high-quality materials and coatings that resist corrosion and minimize the formation of rust. Additionally, we practice strict maintenance schedules to ensure our equipment remains clean and dry, reducing the likelihood of rust-related issues.


Ensuring consistent product quality and appearance is one of our top priorities. By leveraging preloading techniques for cores, we minimize issues such as excessive flash or other defects, resulting in a high-quality finished product. Our meticulous attention to detail and commitment to precision ensures that our injection mold slides produce consistent, reliable results every time.

Related Topic ➻ The Best Design for Plastic Injection Molding: Tips and Tricks for Success

Injection Mold Slide Maintenance

Mold Releases and Cleaners

We recommend using high-quality mold releases to ensure the injection mold slide operates smoothly and efficiently during production. Mold releases provide an effective barrier between the mold surface and the plastic materials, aiding in the smooth ejection of parts. Additionally, using the proper mold cleaner is crucial for maintaining optimal injection mold slide performance. Regular cleaning of the mold slide helps to remove contaminants, uncured resin, and residue build-up, ensuring the longevity and proper functioning of the mold.

Rust Preventives

Rust preventives protect the injection mold slide against corrosion and damage. Rust can lead to premature wear, increased maintenance costs, and reduced mold life. To prevent rust formation, it’s essential to apply high-quality rust preventives on exposed surfaces of the mold slide, especially after cleaning. Consistent application of rust preventatives aids in maintaining the efficiency and lifespan of the injection mold slide.

Purging Compounds

Purging compounds are essential for maintaining a clean and efficient injection mold slide. They help to remove contaminants, excess resin, and unwanted colors from the mold. Using purging compounds compatible with your specific injection molding materials and machinery is necessary. Proper purging of the mold slide can help reduce downtime, minimize waste, and improve overall productivity in the injection molding process.

By following these guidelines and utilizing the appropriate mold releases, mold cleaners, rust preventives, and purging compounds, we can ensure our injection mold slide assemblies’ proper maintenance and efficient operation.

Related Topic ➻ Pros and Cons of Injection Molding: A Comprehensive Analysis

Frequently Asked Questions

What are the main components of an injection mold slide?

The main components of an injection mold slide include the slide, angle pin (also known as cam pin, horn pin), guide block, and guiding pin. The guiding pin helps ensure that the cavity and the mold’s core are correctly matched and protects the core of the plastic product during injection molding.

How do lifters function in injection molding?

Lifters are used in injection molding to release undercuts or recesses in the molded part. They are activated during mold opening and closing, working with the other mold components to create a relative movement that separates the molded part from the mold. Lifters help to simplify the overall mold design and reduce the need for complex slides or side-action components.

What is the purpose of a tunnel slide in injection molding?

A tunnel slide, also known as a tunnel gate, is a gating system used in injection molding. The purpose of a tunnel slide is to create an opening or passage through which the molten plastic can flow into the mold cavity, creating a seamless connection between the molded part and the runner system. Tunnel slides are beneficial for reducing visible gate marks on the molded part and minimizing post-molding operations such as trimming.

How to calculate mold slider dimensions?

Calculating mold slider dimensions involves considering various factors such as the length of the corresponding undercut (H1), the horizontal travel distance of the slide (S), the vertical distance of the guide block in the slide (H), and the angle between the angle pin and the slide (α). The following formulas can be used:

H1 ≧ 1.5W (W represents the width of the slide)
S = T + 2-3mm (T is the undercut of the finished product)
S = H * sinα-δ / cosα (δ is the gap between the angle pin and the slide, generally 0.5MM)

What is the role of hydraulic slides in injection molding?

Hydraulic slides, or cores, are used when a conventional mechanical slide is insufficient to release undercuts or other complex features in a molded part. They utilize hydraulic pressure to actuate the slide movement, providing more precise control and higher forces than mechanical slides. Hydraulic slides can be especially beneficial for large or intricate mold designs, as they can accommodate greater distances and support more demanding part geometries.

What are the key differences between side-action and horn pin injection molding?

Side-action injection molding uses mechanical or hydraulic slides to release undercuts, and, as the name suggests, the slides move in a horizontal or lateral direction perpendicular to the mold opening and closing. On the other hand, horn pin injection molding, also known as cam pin or angle pin molding, uses an angled pin system to drive the slide movement. The opening of the press causes the slide motion in horn pin injection molding, and the angled pin withdrawing from the angled hole moves the slide back to release the undercut.

Tags: , , , , , , , , , , ,
Previous Post
CNC Machining Shop Mastery
CNC Machining Electrical Discharge Machining Laser Cutting Service Rapid Prototyping Tool and Die Making

CNC Machining Shop Mastery: Expert Tips for Precision Manufacturing

Next Post
Tube Laser Cutting
CNC Machining Laser Cutting Service Tools

Tube Laser Cutting: Revolutionizing Manufacturing Efficiency