Aluminum Casting Rotor: Manufacturing Process and Technical Conditions

Aluminum casting rotor are favored for their lightweight, excellent conductivity, and durability. In this blog post, we will delve into the aluminum casting rotors, shedding light on the entire process, from the choice of materials to quality control. By the end of this article, you will have a comprehensive understanding of how aluminum casting rotors manufacturing process and the critical technical conditions that govern their production.

What is aluminum casting?

Aluminum casting is the process of creating complex parts and components by pouring molten aluminum into a mold, allowing it to cool and solidify. It’s a versatile and cost effective method for producing a wide range of products, including rotors.

aluminum casting

Manufacturing Process

1. Material Selection and Preparation:

The process begins with the selection of a suitable aluminum alloy or aluminum ingots. Aluminum ingots or scrap are melted in a furnace to form a molten aluminum pool. Alloying elements may be added at this stage to achieve the desired material properties.


2. Mold Preparation:

Vertical or horizontal casting machine tools are used to make suitable molds according to the shape and size of the rotor and manufacturing requirements.

3. Die Casting Process:

The molten aluminum is carefully poured into the prepared mold. Depending on the casting method, this can involve gravity pouring, centrifugal casting, or pressure casting.

4. Solidification and Cooling:

As the molten aluminum is poured into the mold, it begins to solidify. Proper control of the cooling process can make the rotor quality more stable and reduce the occurrence of defects such as shrinkage holes and cracks.

5. Removal from the Mold:

After the aluminum has fully solidified and cooled, the rotor is carefully removed from the mold. This process is also called demolding.

6. Trimming and Finishing:

Employing various finishing processes such as trimming, machining, and grinding to achieve the required surface quality.

7. Quality Control and Inspection:

Using non-destructive testing methods, like X-ray inspection to ensure the integrity of the casting rotor.

Method of Casting

Gravity Pouring

Working principle: Gravity pouring, as the name suggests, relies on the force of gravity to feed the molten aluminum into the mold. The molten metal is poured from a furnace or crucible directly into the mold, allowing gravity to control the flow.

Applications: Gravity pouring is often suitable for simpler rotor designs and is a cost-effective method suitable for small to medium-sized rotors.

Advantages: This method is straightforward and requires minimal equipment, making it accessible for a wide range of applications. It is particularly effective for producing rotor components with uncomplicated shapes.

Centrifugal Casting

Working principle: Centrifugal casting involves spinning the mold at a high speed while pouring the molten aluminum. The centrifugal force evenly distributes the liquid metal throughout the mold, ensuring that the well-formed rotor’s shape and the uniform grain structure.

Applications: Centrifugal casting is ideal for rotors with varying wall thicknesses. It’s commonly suitable for large rotors and is effective in reducing defects like porosity.

Advantages: This method offers exceptional control over the material distribution and grain structure, resulting in rotors with superior strength and integrity.

Pressure Casting

Working principle: Pressure casting, also known as die casting, involves injecting molten aluminum into a mold cavity under high pressure.

Applications: Pressure casting applies for rotors with extremely complex shapes, fine details, and high tolerance requirements. The production of small to medium-sized rotors with precise specifications using it.

Advantages: Pressure casting allows for excellent dimensional accuracy. It’s a rapid and efficient process, making it suitable for high-volume production. The high-pressure conditions help minimize defects and porosity.

Advantages of using aluminum in rotor manufacturing


Aluminum’s low density reduces the overall weight of the motor, which is crucial for applications such as automotive and aerospace.

High Conductivity

Aluminum efficiently conducts electricity and heat, making it ideal for managing the thermal characteristics of the motor.

Corrosion Resistance

Aluminum naturally resists corrosion, which extends the lifespan of the rotor and reduces maintenance costs.

Types of rotors made through casting

Squirrel Cage Rotors

Squirrel cage rotors are the most common type of rotors used in induction motors. They consist of aluminum or copper bars set into grooves and connected at both ends by short-circuiting rings.

Due to their robustness and simplicity. The pumps, fans, blowers, and conventional electric motors use squirrel cage rotors.

aluminum squirrel cage rotor

Wound Rotor (Slip Ring) Rotors

Wound rotors have windings that are laid into the rotor’s slots, which are connected to slip rings. Through these slip rings and brushes, the rotor windings can be connected to external circuits.

They are suitable for applications where variable speed and torque control are necessary, such as in elevators and cranes.

Double Squirrel Cage Rotors

Double squirrel cage rotors combine elements of both squirrel cage and wound rotor designs. They have an outer squirrel cage winding for efficient starting and a secondary inner squirrel cage winding for higher operating efficiency. These rotors offer a compromise between the reliability of squirrel cage rotors and the versatility of wound rotors.

Permanent Magnet Rotors

Permanent magnet rotors incorporate powerful magnets within the rotor’s core. These magnets generate a consistent magnetic field, making them highly efficient for various applications, especially in brushless DC motors and generators. They offer high power density, reduced energy consumption, and improved control.

Our Capability For Aluminum Die Casting Rotor Core

What sets us apart is the double cage construction approach. The double cage construction provides better control over magnetic fields, reduces losses, and produces more robust and high-performing electric machines.

Motornoe uses fully automated vertical, and high-pressure horizontal die-casting systems to die-cast rotor cores. We can manufacture various sizes of aluminum rotor cores and a largest outer diameter of up to 1250mm.

aluminum die casting rotor capability


The process flow of die-casting aluminum for motor rotors is complex and requires rigorous and meticulous operation. Only by mastering the production technology of die-casting aluminum can the quality and production efficiency of die-casting aluminum parts be improved.


In Which Industries Are Aluminum Die Casting Rotors Commonly Used?

Aluminum die-casting rotors find application in various industries, including automotive, aerospace, industrial machinery, and renewable energy. They are essential in powering a wide range of electric machines.

Can Aluminum Casting Rotors Be Customized for Specific Applications?

Yes, aluminum die-casting rotors can be customized to meet the unique requirements of different applications. This includes varying the design and assembly, alloy composition, and technical conditions to optimize performance.

What is the difference between aluminum cast rotor and copper cast rotor?

The primary difference between aluminum cast rotors and copper cast rotors lies in the materials used for their construction, which has a significant impact on their properties and applications:

Material Composition:

Aluminum cast rotors are made primarily of aluminum and may contain alloying elements.

Copper cast rotors are predominantly composed of copper.

Weight and Inertia:

Aluminum rotors are significantly lighter than copper rotors, which reduces the overall weight of the electric machine.

Copper rotors are heavier due to the higher density of copper.

Electrical Conductivity:

Aluminum is a good conductor of electricity, though not as conductive as copper.

Copper is one of the best electrical conductors available. Copper rotors are chosen when exceptionally high electrical conductivity is essential, such as in high-performance electric motors and generators.

Corrosion Resistance:

Aluminum has natural corrosion resistance, which is advantageous in applications where exposure to moisture and environmental elements is a concern.

Copper is prone to corrosion when exposed to certain conditions and environments. Protect coatings or treatments are often required to mitigate corrosion.


Aluminum rotors are commonly used in a wide range of applications, such as in residential and commercial HVAC systems, automotive components, and some industrial motors.

Copper rotors are often employed in specialized applications that demand exceptionally high electrical conductivity and where weight considerations are less critical, such as in high-performance electric machines.

Try to contact us for high-quality motor cores in China.