Comprehensive Guide to Tooling Die Casting Mold Design

Understanding the criticality of mold design and components in the die casting process. It can significantly improve productivity and product quality.

And the selection and design of the mold, especially the correct use of key components such as cavity blocks, cores and slides. This directly affects the accuracy and durability of the castings.

At the same time yinc understand the function of different mold types and the design of closure system. It can also help you optimize your manufacturing process.

Next, we’ll take a closer look at these key elements to provide you with a practical guide. To ensure that your tooling die casting design and manufacturing process is the best it can be.

Why are molds so important to die casting?

Molds are critical in the die casting process because they directly affect the quality of the final product. First of all, the mold ensures the exact shape and size of the casting. Without accurate molds, castings may have dimensional deviations or inconsistent shapes.

Second, mold design affects production efficiency. A well-designed mold can reduce production time and increase production speed, thus reducing costs. The surface quality of the mold is also very important. A good quality mold reduces surface defects such as porosity and cold segregation in the casting.

The design of the runner system ensures that the molten metal flows evenly. This approach effectively prevents castings from porosity or incomplete filling.

The durability of the mold is also critical. High-quality molds can be used stably for a long time under high temperature and high pressure conditions. This will reduce the frequency of repair and replacement.

The design and manufacture of the mold directly determines the quality and production cost of die casting products. Ensuring the accuracy, efficiency and durability of the mold is the key to successful die casting.

Die Casting Molds Components

Molding system

The molding system is responsible for determining the final shape of the casting. It consists of the cavity/core/slide and the insert pins. These parts form the external and internal structure of the casting when the mold is closed. The formation of the part is precisely controlled.

Mold frame system

The mold frame system consists mainly of steel plates and frames. It holds the various parts of the mold together. It ensures that the mold can be properly mounted on the die casting machine, maintaining stability and accuracy.

Ejection system

The ejection system is used to push the casting out of the mold after it has been formed. This system consists of an ejector unit and an associated return unit. They work together to ensure that the casting can be separated and removed smoothly.

Runner System

The runner system directs the flow of molten metal from the die casting machine into the mold. It consists of three parts: the runner, the gate and the inner gate. They work together to control the flow path and speed of the metal, which has a direct impact on the fill quality of the casting.

Overflow System

The overflow system is used to remove air and excess metal from the mold. The main components are the overflow and exhaust tanks. These components ensure that air and redundant metal are effectively removed to improve the quality of the casting.

Other Components

Other components include devices used to position parts and fastening devices for the mold, such as pins and bolts. These components help in the stability and accurate positioning of the mold.

Types of die casting molds

In the die casting process, the choice of mold is crucial. Different types of molds have their own characteristics. They are suitable for different production needs and process requirements. The following is a comprehensive description of the five main types of molds:

Prototype molds

Prototype molds are mainly used in the product development stage. Production strategies usually include methods such as gravity casting and machined casting molds. These molds help verify the functionality and feasibility of the design. They are usually made of aluminum alloy or steel. Have excellent machinability and faster cooling speed. It is more suitable for small batch production and quick adjustment.. Although prototype molds are less durable. But it has the ability of rapid manufacturing to meet the needs of the product testing stage .

Rapid Prototyping Molds

Rapid prototyping molds are used to produce small quantities of parts quickly. It is a special mold made for the purpose of validating the production process or product design. Commonly used materials are aluminum alloys or high-strength plastics. These materials have good thermal conductivity and processing flexibility. The size of rapid prototyping molds can be adjusted as needed. Compared to production molds, they are usually less resistant to heat and less durable. However, manufacturing costs are low, depending on your specific needs.

Production Molds

Production molds are the most common type of mold used in mass production. It has a complex design and manufacturing process. It can withstand high temperatures and pressures. Commonly used materials are high-strength steels such as H13 or P20, which have excellent wear resistance and high temperature resistance. However, the size of the production mold is large, and thus multiple cavity layouts and cooling systems need to be considered in the design. Although their initial cost is high, they offer excellent durability and productivity.

Unit Molds

The unit mold consists of several individual components. It is often used where diversified production needs are required. This mold is typically made of high-strength steel. The design also allows for quick changeover and adjustment of the mold components to accommodate different production batches. Although the initial investment and maintenance costs of a cellular mold may be high. However, its flexibility is an advantage when it comes to adjusting production specifications.

Trimming Molds

Trimming molds are used for the post-processing of castings. This removes excess material and trims the edges. These molds are usually made of wear-resistant steel. This is done to ensure precise shapes and high quality casting surfaces. Although trimming molds are usually small in size, they are highly functional. Currently they are mainly used to improve the appearance quality and dimensional accuracy of castings.

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Die Casting Mold Design Process

Preliminary stage

In the preliminary stage of mold design, design requirements and objectives need to be clarified. This includes product specifications, functional requirements and production goals. The designer will create preliminary design sketches and verify them. This ensures that the mold meets product quality and productivity requirements.

Number of Cavities

The number of cavities is critical in mold design. The designer determines the number of cavities based on production requirements and expected output. Increasing the number of cavities can increase productivity. However, this can also lead to an increase in the complexity of the mold structure. The manufacturing cost of the mold will also increase. Therefore, a balance needs to be found between efficiency and cost.

Projection area

Projection area is the flat space occupied by the product in the mold. The designer determines the projected area based on the geometry and dimensions of the product. This affects the overall design of the mold. This includes mold dimensions, cooling system layout and injection channel configuration.

Mold Volume and Shape

The volume and shape of the mold are key parameters in the design. The designer needs to plan the volume and shape of the mold based on the complexity and size of the product. This ensures that the mold can withstand the thermal expansion and mechanical stresses of production. While maintaining stability and durability.

The most important factors to consider

• Injection channel: The design of the injection channel determines the flow path of the molten metal. The design needs to ensure that the channel is smooth to minimize resistance to flow. At the same time, uneven cooling or porosity should be avoided.
• Mold closure type: Choosing the proper type of mold closure affects the closure performance of the mold and the quality of the casting. The right type of closure can improve mold efficiency and casting integrity.
• Presence of overflow: Overflow design prevents the molten metal from overflowing. Overflow can affect the size and appearance of the casting. Properly designed overflow systems can reduce scrap rates and improve production stability.

Simulation through semi-empirical modeling

Once the design is complete, simulation using a semi-empirical model is required. This helps to predict how the mold will perform in actual production. Simulation can identify design flaws such as uneven cooling or underfilling. Based on the identified defects, the necessary adjustments are made. These adjustments ensure that the performance of the mold and the quality of the castings meet the desired standards.

Key Considerations for Designing an Optimal Die Casting Mold

Mold Sketches: Preliminary sketches help determine the basic design and functional requirements of the mold. The design sketches can be used as a reference for manufacturing the mold to ensure that all components fit together correctly.

Fillets: Fish fillets are used to optimize the flow path of molten metal and reduce flow resistance. By designing fillets, the filling quality and overall strength of the casting can be improved.

Parting Line: The parting line determines how the mold opens and closes and how well the casting separates. Proper parting line design can minimize casting trimming and increase productivity.

Boss: Boss acts as a protrusion in the mold to provide additional support or locating points. It helps enhance the stability of the casting and ensures accuracy.

Rib: Ribs are designed to add strength and rigidity to the mold and prevent distortion. In castings, ribs help improve structural stability and durability.

Holes and Windows: Holes and windows are used to enable ventilation, helping to expel gases and air bubbles from the molten metal. They are also used for cooling and assembly functions to ensure casting quality.

Symbols: Symbols on the mold help with proper identification and operation during the production process. Symbols can also be used to mark critical components and adjustment points for easy maintenance and corrections.

Wall thickness: The design of the wall thickness directly affects the strength of the mold and ensures its stability under high pressure. Proper wall thickness improves the quality of the casting and reduces defects and scrap.

Mold Components and Terminology

In the design and manufacture of die casting molds, it is important to understand standard mold components. Understanding terminology is equally critical. This helps ensure mold functionality and productivity. Below are some common mold components and descriptions of their functions:

Cavity Blocks or Cavity Inserts

Cavity blocks or inserts are critical parts of a mold used to form part geometry. They are typically made of high-quality tool steel and heat-treated to enhance hardness and wear resistance. Cavity blocks consist of a main cavity and additional inserts. They are often equipped with cooling channels to ensure mold temperature control. These components directly affect the accuracy and surface quality of the casting. Cavity blocks are costly to design and manufacture and often include complex custom machining.

Parting Lines

The parting line is the boundary formed when a mold is closed, usually located where the two halves of the mold meet. This line exists due to the natural formation of the mold as the metal fills the cavity when the mold is closed. Properly designed parting lines can minimize cosmetic defects such as marks or flaws in the casting. The location of the parting line needs to be considered during design to minimize the impact on the appearance of the final product. The structural integrity of the casting also needs to be ensured.

Core or core pin

Cores are removable parts used to form the internal features of a casting. They are usually cylindrical, but can be designed in a variety of shapes as required. Cores are usually made of steel and can be activated by the mold’s mechanical system or hydraulics. The design of the core needs to take into account the internal structure of the part and how it is assembled. This ensures that the core is able to accurately form the desired internal features.

Slider or Slider Core

Sliders are components of a mold used to create complex shapes that cannot be achieved by the basic opening and closing of the mold. Sliders can move in the direction of the parting line and are typically used for protruding or recessed parts of a casting. The slider system includes several components such as a slider front end, a wear plate and a locking mechanism. They can be activated by means of angle pins or hydraulic cylinders. The design needs to ensure that the path of movement of the slide does not interfere with the removal of the casting or the closing of the mold.

Ejector plates and pins

Ejector plates and pins are used to push cooled castings out of the mold. The ejector pins are usually actuated by the ejector plate. These parts are activated when the mold is opened to push the casting out of the mold cavity. The position and number of ejector pins need to be precisely calculated to avoid leaving unwanted marks on the surface of the casting. Choosing the right ejector ensures the integrity of the casting and the long-term reliability of the mold.

Work with Yonglihao Machinery for expert advice

Understanding the design and components of die casting molds is critical to improving productivity. The mold directly affects the quality of the product. To be successful, it is important to be clear about the purpose of each mold, the impact of the closure system, and the function of key components. Accurate design and manufacturing can greatly improve the accuracy and durability of castings.

For optimum production results. Contact the engineers at Yonglihao Machinery for specialized metal die casting services. We offer specialized material options, surface treatment solutions, and related manufacturing advice. We can provide you with the best quality casting support to guarantee reliable mold performance and high quality castings.