Slide moulding is a critical technique in injection molding that enables the production of complex plastic parts with undercuts, side holes, and intricate geometries. As product designs become more compact and functional, slide moulding has become an essential solution for manufacturers seeking precision, efficiency, and design freedom.
This guide explains what slide moulding is, how it works, its advantages, applications, and key design considerations.
What Is Slide Moulding in Injection Molding?
Slide moulding, also known as side-action molding, is an injection molding process that uses movable mold components—called slides or side actions—to form features that cannot be created using a standard two-plate mold.
Unlike fixed mold cores, slides move horizontally or at an angle during the molding cycle. They retract before part ejection and return to position before the next injection cycle.
This technique allows manufacturers to mold complex features in a single process without secondary machining or assembly.
How Slide Moulding Works
The slide moulding process follows these basic steps:
- The mold closes, and the slides move into position.
- Molten plastic is injected into the mold cavity.
- The plastic cools and solidifies around the slides.
- The slides retract as the mold opens.
- The finished part is ejected cleanly without damage.
Slides are typically driven by angled guide pins, hydraulic cylinders, or cam mechanisms, depending on part complexity and production volume.
Key Advantages of Slide Moulding
Slide moulding offers several benefits in injection molding applications:
Enables Complex Part Design
Slides allow undercuts, side holes, threads, and locking features to be molded directly into the part.
Reduces Secondary Operations
By forming complex features in-mold, slide moulding eliminates the need for drilling, cutting, or assembly.
Improves Part Accuracy
Integrated molding ensures better dimensional consistency compared to post-processing methods.
Enhances Production Efficiency
Although tooling costs are higher, cycle times and per-part costs are lower in mass production.
Common Applications of Slide Moulding
Slide moulding is widely used across various industries:
Automotive Components
- Clips and fasteners
- Sensor housings
- Connector bodies
Consumer Electronics
- Device enclosures
- Charging ports
- Snap-fit housings
Medical Devices
- Diagnostic housings
- Plastic connectors
- Precision enclosures
Industrial and Electrical Parts
- Terminal blocks
- Switch housings
- Cable management components
Design Considerations for Slide Moulding
Proper design is essential for successful slide moulding.
Undercut Size and Location
Undercuts must be designed to allow smooth slide movement and clean release without excessive wear.
Draft Angles
Adequate draft angles on slide-formed surfaces reduce friction and extend mold life.
Slide Travel Distance
Long slide movements increase mold complexity and risk. Designs should minimize slide stroke where possible.
Material Selection
Some materials, especially glass-filled plastics, cause higher wear on slides and require hardened steel components.
Slide Moulding vs. Other Molding Solutions
While slide moulding is highly effective, it is not always the best solution. Alternatives include:
- Insert molding for metal integration
- Lifters for shallow undercuts
- Post-machining for low-volume production
An experienced injection molding manufacturer can evaluate the most cost-effective approach based on volume, tolerance, and design requirements.
Conclusion
Slide moulding in injection molding is a powerful technique for producing complex plastic parts with precision and efficiency. By integrating side actions into the mold design, manufacturers can reduce assembly steps, improve part quality, and achieve advanced geometries in a single molding cycle.
For high-volume production of parts with undercuts or side features, slide moulding remains one of the most reliable and cost-effective solutions in modern injection molding.
