What Is an Angular Pin?
An angular pin is a component used in injection molding molds to facilitate the molding of products with undercuts. It operates within a special mold feature known as a slide core, enabling the production of complex shapes. Angular pins, typically cylindrical, demand high precision and durability due to their contact with the slide core. They are crafted from wear-resistant materials like high-strength tool steel to withstand the rigors of use.
Applications of Angular Pins
Angular pins play a crucial role in moving slide cores to form and de-mold parts with undercut areas and complex geometries. An undercut is a recess that blocks the straightforward demolding path, necessitating angular pins to reposition the slide core for obstacle-free mold removal. These pins are instrumental in manufacturing diverse resin-molded products, including window frames, door handles, electronic device housings, and even cups with handles.
Principle of Angular Pins
The core function of an angular pin is to synchronize with the slide core, or another mold component, to mold undercut areas and facilitate part removal. Attached to the slide core or plate within the molding die, angular pins guide the slide core’s movement, essential for undercut formation.
More About Angular Pins
1. Movement of Angular Pin and Slide Core
Injection and Filling: The mold is closed, and the plastic material is injected, with the undercut area secured by the slide core and angular pins.
Mold Opening: Post-cure, the mold opens, typically allowing angular pins to rotate or slide, releasing the undercut section.
Product Removal: With the undercut freed, the molded product is ejected, after which the mold closes for the next cycle.
2. Angular Mounting Angle
Angular pins are installed at an angle to the mold’s movement line, balancing slide volume needs against breakage risks. A standard tilt up to about 20 degrees is common, with pin length adjustments possible to achieve similar outcomes without compromising mold movement space.
3. Material of Angular Pins
Due to their constant friction against the slide core and exposure to high temperatures, angular pins must be wear-resistant, strong, and thermally stable. High carbon steel, like SUJ-2, is preferred, often treated for hardness and wear resistance.
4. Types of Undercut Treatment
Slide Core Method: A straightforward approach using an angular pin and slide core for undercut formation, with the angular pin guiding the slide core’s movement.
Inclined Slide Method: Suitable for small undercuts, this method relies on a slide unit and rod without angular pins, driven by mold movement for product ejection.
Hydraulic-Driven Slide System: Utilizes a hydraulic cylinder to move large slide cores independently of mold opening, offering flexibility for complex designs.