What Are the Parts of a Mould? A Look Inside the Tooling by Dongguan Hie Hardware Co., Ltd.

As a provider of precision tooling solutions here in Dongguan, Guangdong Province, China, Dongguan Hie Hardware Co., Ltd. understands that the mould is the heart of the manufacturing process for countless products. But what exactly constitutes a mould? Let's break down the key components that work together to shape the materials we rely on daily.

While the specific design can vary greatly depending on the material being moulded (plastic, metal, etc.) and the complexity of the final part, there are fundamental parts that are common to most moulds. For the purpose of this blog, we'll primarily focus on the components found in injection moulds, a very prevalent type of mould we work with extensively.

Here are the essential parts of a typical injection mould:

1. Mould Base:

• This is the foundational structure of the entire mould assembly. It provides the necessary support and framework for all the other components.
• It typically consists of top and bottom clamp plates that attach the mould to the moulding machine, as well as A-plates (cavity side) and B-plates (core side) that house the actual shaping components.
• Spacer blocks or support pillars are often used to maintain the correct distance between the A and B plates.

2. Moulding System (Cavity and Core):

• Cavity: This is the negative impression of the external shape of the part to be moulded. It's usually located on the A-plate side of the mould. The molten material fills this space to form the outer surfaces of the product.
• Core: This component forms the internal features or undercuts of the moulded part. It fits into the cavity, creating the part's inner shape. The core is typically located on the B-plate side, from which the part is often ejected.
• In complex moulds, inserts might be used within the cavity and core to create intricate details or to allow for easier replacement in case of wear.

3. Feed System:

This system guides the molten material from the injection moulding machine's nozzle into the mould cavities:

• Sprue Bushing: This is the entry point for the molten material into the mould, connecting directly to the machine's nozzle.
• Runner System: These are channels machined into the mould plates that distribute the molten material from the sprue to the individual cavities. This can include main runners and sub-runners.
• Gates: These are small openings that connect the runners to the mold cavities. They control the flow rate and the point at which the material enters the shaping area.
• Cold Slug Well: A small recess designed to trap the initial, cooler portion of the injected material, preventing it from entering the cavities and causing defects.
• In more advanced systems, a manifold and hot runners might be used to keep the plastic molten throughout the feed system, eliminating the sprue and runners and reducing waste.

4. Ejection System:

This mechanism is responsible for pushing the solidified moulded part out of the mould cavity:

• Ejector Plate Assembly: This includes the ejector plate and the ejector retainer plate, which together hold and guide the ejector pins.
• Ejector Pins: These are pins that directly contact the moulded part and push it out of the cavity or off the core when the mould opens.
• Sleeves, Blades, and Lifters: For more complex ejection needs, sleeves, flat ejector blades, or angled lifters might be used to eject parts with undercuts or intricate geometries.
• Return Pins: These ensure the ejector plate assembly retracts as the mould closes for the next cycle.

5. Cooling System:

Efficient temperature control is crucial for the solidification of the molten material and the overall cycle time:

• Cooling Channels (Waterlines): These are channels drilled through the mould plates that allow for the circulation of coolant (usually water) to regulate the mould temperature.
• Baffles and Bubblers: These are internal components within the cooling channels that enhance heat transfer.
• Heating Elements: In some cases, heating elements might be incorporated to maintain specific mould temperatures.

6. Venting System:

Proper venting allows air and gases trapped in the mould cavity during injection to escape, preventing defects in the final part:

• Vents: Small channels or porous inserts strategically placed in the mould to allow air and gas to escape as the molten material fills the cavity.

7. Guiding and Alignment Components:

Precise alignment of the mould halves is essential for part accuracy and preventing damage:

• Guide Pins and Bushings (Leader Pins and Sleeves): These components ensure the cavity and core halves of the mould align correctly during closing.
• Locating Ring: This helps to center the mould accurately with the injection moulding machine's platen.
• Interlocks: These can be used to provide additional precise alignment and stability between mould sections.

Conclusion:

A mould is a complex assembly of carefully engineered components working in unison to transform raw materials into finished products. Understanding the function of each part, from the robust mould base to the intricate cooling and ejection systems, provides valuable insight into the precision and engineering involved in modern manufacturing. At Dongguan Hie Hardware Co., Ltd., we are dedicated to mastering the design and application of these mould components to deliver high-quality tooling solutions for our clients.