Factors to be considered in aluminum die casting mold design

Aluminum die casting produces metal parts by injecting molten aluminum into a mold cavity under high pressure.

The mold cavity is designed to match the shape and size of the desired part. However, creating a mold for aluminum die casting is complex.

There are many factors that need to be considered to ensure the quality and performance of the cast part. This blog post will discuss some of the most critical factors affecting the aluminum die-casting mold design.

Die Casting Mold

- Part shape

The shape of the part determines the complexity and difficulty of the mold design. Part shapes should be as simple and symmetrical as possible to avoid undercuts, thin sections, sharp corners, and other features that could cause defects or make molding difficult. The part shape should also allow for easy ejection from the mold cavity without damaging the part or the mold.

- Part size

Part size affects mold size, weight, and cost. The larger the part, the larger the mold cavity and the more material and energy are required to form it. Part dimensions should be optimized to minimize the waste of material and energy while meeting the functional and aesthetic requirements of the part.

- Part wall thickness

Part wall thickness affects the filling and solidification of molten aluminum in the mold cavity. Wall thickness should be uniform throughout the part to avoid hot spots, cold spots, shrinkage cavities, blow holes, and other defects.

Wall thickness should also be as thin as possible to reduce material usage and cycle time while maintaining the strength and rigidity of the part.

- Part tolerance

The tolerance of the part refers to the allowable variation in the dimensions and geometry of the part. Tolerances depend on the accuracy and precision of mold design and manufacturing, as well as the stability and repeatability of the molding process.

Tolerances should be specified according to the function and application of the part and should be within the capabilities of the tooling and process.

Aluminum Die Casting Processing

- Part surface quality

Part surface quality refers to the appearance and texture of the part surface. Surface quality depends on the smoothness and cleanliness of the surface of the mold cavity, as well as the flow and cooling of the molten aluminum in the mold cavity.

The surface quality should meet the aesthetic and functional requirements of the part, such as glossiness, roughness, color, coating, etc.

- Mechanical properties of parts

The strength, hardness, flexibility, toughness, fatigue resistance, corrosion resistance, and other characteristics of parts materials are the mechanical properties of parts, which depend on the aluminum alloy’s composition and purity, and the molding parameters such as temperature, pressure, and cooling rate, and which should meet the part’s performance and durability requirements such as load-bearing capacity, wear resistance, impact resistance, etc.

- Processing technology

Processing technology refers to the methods and techniques used for forming, such as high-pressure casting, low-pressure casting, gravity casting, vacuum casting, etc.

The processing technology affects the quality and efficiency of the molding process, as well as the design and cost of the mold.

The processing technology should be selected according to the characteristics and requirements of the part, such as shape complexity, size range, wall thickness range, tolerance range, surface quality level, mechanical property level, etc.

- Mold material

The material of the mold affects the durability and performance of the mold. The mold material should withstand the high temperature, high pressure, and abrasion of the molten aluminum, as well as the thermal shock and fatigue of repeated molding cycles.

Mold materials should also have good machinability, weldability, and heat treatment performance to facilitate mold design and manufacturing.

Some typical materials used for aluminum die-casting molds are steel alloys, such as H13 steel, D2 steel, P20 steel, etc.

metal raw material

- Mold structure

The mold structure refers to the arrangement and configuration of the mold components, such as core, cavity, ejector pins, sprue bushing, runner system, etc.

The mold structure affects the filling and solidification behavior of the molten aluminum in the mold cavity and the ejection and separation of the cast part from the mold. The mold structure should be designed to optimize the molten aluminum’s flow path and cooling system in the mold cavity to ensure a smooth and uniform filling and solidification process. The mold structure should also facilitate an easy and safe ejection and separation process for both the cast part and the runner system.

- Temperature control

Temperature control is the process of regulating and adjusting the temperature of both the molten aluminum (usually between 650°C to 700°C) and the mold (usually between 200°C to 300°C) during molding, which affects the fluidity and viscosity of the molten aluminum in the mold cavity, as well as the shrinkage and solidification rate of the cast part, and can be achieved by using heaters, coolers, thermocouples, controllers, etc.

- Parting surface

Parting surface, the interface between two or more mold components that separate to release the cast part from the mold cavity, should be located along a plane or a curve that minimizes undercuts or projections on both sides of it and should also be smooth and clean to avoid flash or burr formation on both sides of it.

- Gate system

A gate system is a network of channels that connects a sprue bushing, where molten aluminum enters a mold, with a number of gates, where it enters a mold cavity.

It affects the flow pattern and pressure distribution of molten aluminum in the mold cavity and should be designed to ensure a fast and uniform filling without causing turbulence or air entrapment.

It should also minimize material waste and heat loss by reducing the channel length and cross-sectional area.

Aluminum Die Casting Machine

- Exhaust system

A set of vents or vacuum devices that allow air or gas trapped in a mold cavity to escape during molding is called an exhaust system, which affects a quality and integrity of cast parts by preventing air entrapment or gas porosity defects and should be placed at strategic locations where air or gas tends to accumulate in a mold cavity during filling or solidification, as well as have sufficient size and number to provide adequate venting without affecting a filling or solidification process.

- Cooling system

Cooling system is a term for a series of pipes or channels that circulate coolant (usually water) through a mold during molding to affect a cooling rate and uniformity of cast parts by removing heat from molten aluminum in a mold cavity during solidification, and to provide optimal cooling for different regions of cast parts according to their wall thickness and geometry while avoiding thermal shock or distortion of cast parts or molds by controlling coolant temperature and flow rate.


These are some of factors that need to be considered in aluminum die casting mold design. By taking into account these factors, one can design a suitable mold for producing high-quality aluminum die cast parts with high efficiency and low cost.

If you need any assistance with your aluminum die casting project, please contact us today. We have extensive experience in designing and manufacturing aluminum die casting molds for various industries and applications. We can provide you with customized solutions that meet your specific needs and expectations.

This article was first published on May 30, 2023

Table of Contents

Date Archive

Contact Us

Shatian industrial zone,Kengzi town,Longgang district, Shenzhen, China

Scroll to Top