Mold Design and Types
1. What it is?
A mold (or die) is a tool used for mass-producing products. It is designed to shape products into their desired forms through various processes such as casting, molding, extrusion, and pressing. By using molds, identical products can be manufactured with high precision and consistency, making them indispensable for large-scale production.
2. What is the purpose of using molds?
(1) Precision manufacturing and mass production
Molds are designed with exceptional precision, allowing for the consistent production of products with uniform quality and dimensions. This is particularly advantageous in industries such as electronics, automotive components, and home appliances.
Thanks to molds, identical products can be mass-produced efficiently and at a rapid pace, significantly enhancing production efficiency.
(2) Cost savings
Once a mold is designed and created, it can significantly reduce the per-unit cost of products during mass production, providing considerable economic advantages. While the initial cost of mold creation may be high, its ability to be reused over an extended period results in substantial cost savings in the long run.
Molds are customized to suit different manufacturing processes, enabling various materials to be shaped into the desired forms. Depending on the product’s characteristics, the molding method may vary.
Injection molding is the most commonly used method, while other techniques, such as extrusion, die casting, and pressing, are also applied based on the material and shape.
3. Types
(1) Injection
An injection mold is a process where thermoplastic materials are heated, melted, and injected into a mold to form the desired shape. Simply put, the process involves heating thermoplastic materials → injecting them into the mold using an injection device → cooling the material → separating the product from the mold.
Injection molding is widely used in various industries, such as plastic containers, electronic device cases, automotive parts, and household appliance components. It is particularly suitable for producing plastic products that require high precision, making it a preferred method for many companies.
(2) Extrusion
An extrusion mold is a process that involves melting raw materials, such as metals or plastics, at high temperatures and forcing them through a die under high pressure to form long products with a consistent cross-sectional shape. In this continuous production method, the material is pushed through the mold opening (die) to produce elongated products in the desired shape.
This method is ideal for mass production and enables the creation of diverse cross-sectional designs, making it widely used in industries such as construction, electrical engineering, and automotive manufacturing.
One of the significant advantages of the extrusion process is its ability to produce infinitely long products based on the shape of the mold. This makes it suitable for manufacturing pipes, tubes, profiles, and other long products.
Additionally, it supports the creation of complex cross-sectional designs, enabling the production of window frames, door frames, cable ducts, structural components, and other products with unique shapes.
A key strength of extrusion molding is its wide range of material compatibility. It can process materials such as metals (e.g., aluminum, copper, and steel) and thermoplastics (e.g., PVC, polyethylene, and polycarbonate). This versatility makes extrusion molds highly adaptable and widely applicable across various industries.
(3) Die-Casting Mold
A die-casting mold is a high-precision metal casting process in which molten metal is injected into a mold under high pressure to achieve precise shaping. This process primarily uses non-ferrous metals such as aluminum, magnesium, zinc, and copper. It is ideal for producing metal components that require high precision, excellent surface quality, or complex shapes.
One of the key advantages of die casting is its ability to produce structurally strong products, allowing the mass production of complex metal components while maintaining strength and durability.
However, products made through die casting may require additional post-processing. For example, tasks like removing gates, runners, or excess flash (excess metal), as well as surface finishing or coating, may be necessary.
It is also worth noting that die casting is divided into two main types: hot chamber die casting and cold chamber die casting. The choice of process depends on the type of metal being used and the specific characteristics required for the product.
ㄱ. Hot Chamber Die Casting
source_Ningbo Dongfang Die-casting Machine Tool Co.,Ltd.
In the hot chamber method, the molten metal is integrated with the injector system, allowing the metal to be directly injected as it is heated.
This enables extremely fast injection speeds and short cycle times, making it suitable for mass production. As a result, this method is typically used for low-melting-point metals such as zinc and magnesium.
ㄴ. Cold Chamber Die Casting
source_https://kr.goldeneagle-machinery.com
On the other hand, the cold chamber method involves melting the metal in a separate furnace before injecting it into the mold using an injection system. This method is commonly used for metals with higher melting points, such as aluminum, copper, and brass.
(4) Press Mold
A press mold is used to process materials such as sheet metal by cutting, bending, or shaping them into the desired form. Typically, a metal sheet is placed into the mold, and a press machine applies pressure to shape it as needed.
The main processes involved in press molding include cutting, punching, bending, and drawing, which collectively help form the sheet metal into the desired shape.
Last year, I came across an article about Hyundai Motor Company and Kia developing an automated “Press Mold Design System” for designing vehicle press molds. This news was exciting, as such design systems have the potential to greatly improve manufacturing efficiency if extended beyond automated part design to include various industries involved in mold design. In particular, for product development that requires complex shapes, this system could play a crucial role in reducing design time and costs while enhancing quality.