What are the Different Types of Moulds?

In the vast and dynamic world of manufacturing, moulds are the unsung heroes that shape countless products we use in our daily lives. From the plastic toys that bring joy to children to the complex metal components in automobiles, moulds play a pivotal role. Understanding the different types of moulds is crucial for manufacturers, engineers, and anyone interested in the manufacturing process. This blog post will delve into the various types of moulds, their functions, and their applications across different industries.

• Two - Plate Moulds: Also known as 大水口模 in Chinese, two - plate moulds are the simplest type of injection moulds. They consist of two main parts - a fixed half (the cavity) and a moving half (the core). When the mould closes, the plastic is injected into the space between the cavity and the core. After cooling, the two halves of the mould separate, and the part is ejected. Two - plate moulds are cost - effective and suitable for producing a wide range of plastic parts, from small components like buttons to larger items like plastic containers.

• Three - Plate Moulds: Also called 细水口模，three - plate moulds are more complex than two - plate moulds. They are composed of three main plates. One advantage of three - plate moulds is that they can separate the plastic part from the runner (the channel through which the molten plastic flows) more cleanly, which is beneficial for parts where the runner mark needs to be minimized, such as in some consumer electronics cases. This type of mould is often used for parts with more intricate designs and when multiple gates (the points where the plastic enters the cavity) are required.

• Hot Runner Moulds: In hot runner moulds, the runner system is designed to keep the plastic molten throughout the injection process. This eliminates the need to trim and recycle the runner material, as in cold runner systems. Hot runner moulds are more energy - efficient and can reduce material waste. They are commonly used in high - volume production of plastic parts, especially those where the cost of material and the efficiency of the production process are critical factors.

• Extrusion Blow Moulds: In extrusion blow moulding, the parison is formed by extruding molten plastic through a die. This method is suitable for producing a wide variety of hollow plastic products, from small bottles for cosmetics to large industrial containers. Extrusion blow moulds are relatively simple in design and can be cost - effective for medium - to - high - volume production.

• Injection Blow Moulds: Injection blow moulding starts with injecting molten plastic into a pre - form mould to create a pre - form, which is a small, hollow tube - like structure. The pre - form is then transferred to a blow mould, where air is blown into it to expand the pre - form and form the final product. Injection blow moulds are often used for producing high - quality, precision - made hollow plastic parts, such as pharmaceutical bottles and some food containers, as the process can ensure better control over the wall thickness and shape of the final product.

• Sand Casting Moulds: Sand casting is one of the oldest and most common casting processes. Sand casting moulds are made by packing sand around a pattern, which is a replica of the final part. The sand is compacted to form the shape of the mould cavity. Once the pattern is removed, the molten metal is poured into the cavity. Sand casting moulds are relatively inexpensive to produce and are suitable for casting large parts or parts with complex shapes. They are often used in the production of engine blocks, machine parts, and artistic sculptures.

• Die Casting Moulds: Die casting moulds are made of metal, usually steel or aluminum. In die casting, the molten metal is injected into the mould cavity under high pressure. This process allows for the production of parts with high precision, smooth surfaces, and complex geometries. Die casting moulds are widely used in the automotive, electronics, and aerospace industries for manufacturing parts such as engine components, electronic enclosures, and aircraft fittings.

• Investment Casting Moulds: Also known as lost - wax casting, investment casting involves creating a wax pattern of the desired part. The wax pattern is then coated with a ceramic shell. Once the shell is hardened, the wax is melted and removed, leaving a hollow cavity. Molten metal is then poured into the cavity, and after cooling and solidification, the ceramic shell is broken away to reveal the finished casting. Investment casting moulds are used to produce parts with very high precision and intricate details, such as jewelry, dental implants, and some aerospace components.

• Open - Die Forging Moulds: In open - die forging, the metal workpiece is placed on a stationary anvil, and a moving die is used to shape the metal by applying blows or pressure. Open - die forging moulds are relatively simple in design and are suitable for producing small - to - medium - sized batches of parts with non - standard shapes. This method allows for greater flexibility in shaping the metal but may require more skilled operators.

• Closed - Die Forging Moulds: Closed - die forging, also known as impression - die forging, involves using two dies that fit together precisely. The metal is placed in the die cavity, and when the dies are closed, the metal is forced to fill the entire cavity, resulting in a more accurate and complex shape. Closed - die forging moulds are used for high - volume production of parts with consistent quality and are commonly used in the automotive and machinery industries for manufacturing components such as gears, crankshafts, and connecting rods.