Types and Functions of Moulds

Different Kinds of Moulds

• Various types of molds exist, each with unique characteristics and applications.
• Standard molds are readily available and have been tested extensively.
• Functional guarantee is assured for standard parts.
• These parts are readily available for replacements and repair.
• CAD data is accessible for various components.

Tasks and Functions of a Mould

• Transfer motion: Molds facilitate the movement of components during the injection molding process.
• Absorb forces/retain shape: Molds absorb forces exerted during molding and maintain the shape of the components.
• Guiding of mold parts: Guiding components prevent misalignment and ensure proper positioning.
• Long lifetime: Molds are designed to withstand repeated use and have long operational lifespans.
• Gating: Conduits which direct molten plastic into the mold cavity.
• Venting: Channels that allow gases to escape during the molding process.
• Tempering: Cooling or heating of the mold to maintain temperature control.
• Demoulding: Removing molded components from the mold cavity.
• Undercuts: A component that may require additional steps for removal.
• Guides & center: Essential for proper alignment.

Parts of an Injection Mould

• Mould Core: Provides support and shape to the workpiece.
• Mould Cavity: The cavity/container where the workpiece is created.
• Bolts: Used to secure components in the mould.
• Guide Pins: Enable proper alignment of components in the mold.
• Risers: Channels for efficient material flow during molding.
• Ejector Plate: Plate responsible for ejection of the molded workpiece.
• Ejector Locating Plate & Retainer: Ensures correct ejector pin placement.
• Bolster Sleeves: Maintains alignment during operations.
• Moving half support plate: Maintains the structural integrity of the moving half.
• Guide Bushes: Offer bearing surface to avoid wear.
• Retaining Plate: Prevents ejector pins from shifting.

Steels for Functional Parts/Standard Parts

• Steels are chosen based on their mechanical properties for specific functional parts within molds.
• Application related properties such as Hardness, Strengthen and Strengthened properties are required.
• Specific steel types are detailed such as alloys and their composition which determines their strength and usage.
• Data like hardness values and strengthening values are detailed for each part.

Tolerances of Shafts and Bushes

• Precision control during manufacturing via tolerances.
• Clearances are specified and dimensions are detailed for precision assembly.
• Specifications of tolerance range for shafts and bushes are provided.

Kinds of Injection Moulds

• Basic Mould: This type is characterized by its simple design and straightforward demolding mechanisms using gravity and ejectors.
• Slider Mould: Multiple opening directions for a range of components.
• Split Mould: Ideal for larger molds with threads or undercuts.
• 3-Plate Mould: Specifically for complex shapes with multiple gating points.

Core Puller

• It uses hydraulic or pneumatic mechanisms to eject large components (such as cores).
• Controlled by switches which automate the process.
• Quality depends on guided surfaces.

Screw-Mould

• Uses a collapsing core to demold threads.
• Multiple cavities enable diverse component production.
• Rack Steering: Threads rotate by mechanical or electric means.
• Spindle: The core is driven by gear spindles.

Multi Cavity Mould

• This allows multiple components to be produced simultaneously.

IMD Moulding/IML Moulding

• A manufacturing process that inserts different materials like films or parts into the main section.
• Various types of insertion methods ensure precision control during the molding process.

Stack Mould

• A complex structure with at least two parting lines.
• High production output on one machine
• Mostly for flat components due to suitable design.

Change Mould

• Allows simple changes and quick conversion for different molds.