Have you ever wondered how the small axial flux stator cores are made? Despite their small size, they are the “brain” of the motor’s performance, and produce axial flux stator laminations process is not simple.
What is the main manufacturing process of axial flux stator?
There are two mainstream approaches: One is using silicon steel sheets, which are stamped and then wound into shape, much like a “coreless roll of paper.” The other method uses SMC (Soft Magnetic Composite) powder injection molding.
What is an Axial Flux Motor Stator?
Axial Stator
In these axial motors, the stator core is designed in a disc or thin pancake shape, hence it is called a disk stator or axial flux stator. Its magnetic flux flows parallel to the motor axis, unlike traditional radial flux motors, the magnetic flux flows from the center radially outward.
Additionally, there are several structural configurations for axial flux motors:
Single stator/single rotor structure
Single stator/double rotor structure
Double stator/single rotor structure
Multiple stators/multiple rotors structure
Their unique design allows for a more compact and lightweight motor construction, making them ideal for applications where space and weight considerations are crucial.
So, how is the stator core lamination used in axial motors made?
Using Silicon Steel for Axial Flux Stator Lamination Manufacturing Process
Material Preparation
Axial flux motor stator lamination stacks typically use non-oriented silicon steel sheets that range from 0.2mm to 0.5mm in thickness. Common grades include B35A250, B35A300, 35W270, 50W600, and others.
The reason for choosing electrical steel is its high magnetic permeability and low eddy current losses. We can choose self-bonding electrical steel or standard electrical steel.
Next, the silicon steel sheets are cut to the specified width according to customer requirements.
Stamping Mold Production
For custom stator products, stamping molds are made based on the slot shapes and dimensions provided by the customer’s drawings. We also have standard molds for axial motor stator production, such as 107 mm *53.5 mm, 220 mm*110 mm, 300 mm*180 mm, etc.
Stamping and Rolling Silicon Steel Laminations
The axial stator tool is installed on the stamping equipment for debugging. Specialized punching machines designed for axial flux stator laminations are used to form the stator into the required inner diameter (ID), outer diameter (OD), and height.
Axial punch and winding equipment use a servo-synchronized control system to precisely control the stamping frequency and winding speed. This ensures accurate alignment of the slots across different layers within strict tolerance ranges.
Welding Lamination
For stators stamped from silicon steel, spot welding is done at the starting and ending points of the laminates. To prevent deformation during transport, laser welding is usually applied to the back of the stator, and the number of weld seams is based on customer specifications, such as 4, 6, 8, or 9 seams.
Assembling Thread Holes
For connecting the axial stator to other motor components, we can drill holes in the back of the stator. The shape, depth, and size of the holes can be specified by the customer.
Surface Treatment
Once the stator is completed, we grind its surface to remove burrs.
Axial Stator Insulation
The axial motor stator is insulated using epoxy coatings, injection molding, and inserting insulating slot paper before winding.
Axial Stator Winding
Typically, round wire winding is used, and winding follows the connection method specified in the customer’s drawings. For customers requiring only stator teeth, flat wire concentrated winding is also used.
Using SMC Powder Injection Molding To Produce Axial Flux Motor Stator Cores
Soft Magnetic Composite Material Preparation
SMC (Sheet Molding Compound) core material is prepared according to customer specifications. Iron, nickel, and other metals are used as raw materials and alloy elements and magnetizers are added according to specific ratios by technicians.
Somaloy® 3P high-performance soft magnetic composite materials can also be purchased for production.
Ball Milling and Calcination
Employ ball milling and calcination methods to crush the raw materials into fine-grained powder, ensuring uniformity and consistency in particle size.
Mixing and Proportioning
Skilled technicians carefully take a sample of prepared powder. They mix it evenly according to the required ratio. This ensures precise composition for subsequent processing and molding.
Pressing and Molding
Uniformly press the sampled and proportioned powder into shapes such as plates or pipes, forming the motor core parts.
Sintering or Heat Treatment
The pressed molded parts undergo sintering or heat treatment to enhance their magnetic properties and durability. Resulting in the final soft magnetic disk motor stator product.
Surface Treatment
Apply surface treatment to the final product to meet usage requirements, ensuring optimal performance and longevity.
Wire EDM Process
For small-batch prototypes, we use simple molds to form an initial shape for the axial motor stator core. Wire EDM (Electrical Discharge Machining) is then used to cut the stator slot shape for final forming.
Insulation
Unlike silicon steel sheet stators, SMC stators are primarily insulated through injection molding. This can be done by directly molding or by using 3D printing to create winding supports that are then fitted onto the stator teeth.
Winding
SMC axial stators mostly use round copper winding and flat wire winding, which increases the slot fill factor.
Which process should you choose: Silicon Steel Sheet Stamping and Winding or SMC Powder Injection Molding?
Both processes have their advantages, and the choice depends on your specific needs.
If you aim for efficient production, cost control, and traditional manufacturing methods, silicon steel sheet stamping and winding is undoubtedly the preferred choice.
On the other hand, if you focus on high performance and precision design, SMC powder injection molding delivers better results.
Ultimately, the choice depends on the application and performance requirements of the motor. Which method do you think suits your needs better?
Axial Flux Motor Stator Lamination – Choose Lamnow
Lamnow is a professional China manufacturer of electric motor lamination cores. We offer products such as axial flux motor lamination, segmented stator lamination, generator cores, transformer cores, and amorphous cores. We can customize axial stator and rotor cores based on customer specifications, or we can use standard molds for production. If you need axial flux rotors or stators, please contact us free.
Various Applications for Axial Flux Stator Laminations
High-quality stator laminations play a pivotal role in enhancing efficiency and reliability. The high power density and high efficiency axial flux stators and rotors we produce are widely used in electric vehicles, electric motorcycles, electric airplanes, buses, electric bicycles, and robotics.
