self-Bonding motor rotor lamination stacks technology

Self-Bonding Motor Rotor Lamination Stacks Technology

High-performance rotor laminate cores are pivotal in enhancing motor efficiency and performance, thereby reducing energy consumption and noise levels. In this blog, we delve into the technology of self bonding rotor lamination stacks, exploring their advantages over conventional bonding methods like welding and riveting, particularly in the context of the burgeoning electric vehicle (EV) industry.

The Need for High-Performance Rotor Core Materials

High-performance rotor core materials play a crucial role in achieving compact, efficient electric motors, especially in the rapidly evolving landscape of electric vehicles. These motor rotor and stator lamination materials, including 6.5% silicon steel, cobalt-iron, nickel-iron, amorphous nanocrystalline materials, and Soft Magnetic Composites (SMCs), are sought after for their ability to increase magnetic flux density and minimize iron losses.

New Energy Vehicle Motor Lamination Bonding Technology

advancements in electric motor materials

Challenges Of Traditional Bonding Methods

Traditional bonding methods like welding and riveting pose significant challenges in terms of performance, environmental impact, and structural integrity.

Welding, for instance, results in a large heat-affected zone, diminishing motor performance and potentially causing short circuits and reduced insulation properties. Riveting, on the other hand, can compromise the structural integrity of the rotor core, leading to narrower magnetic flux paths and decreased motor efficiency. In addition, both riveting and welding are locally fixed, and the connection force is not high.

Current new energy vehicle motors often rotate at 12,000 rpm or higher at 20,000 rpm, and the fastening strength requirements for the rotor core are also higher. It can be seen that the above process does not seem to be the optimal solution for the rotor core.

bonding vs. riveting for motor laminations

Compared with the above-mentioned welding and riveting, bonded motor core is obviously a better connection process, which can eliminate interlayer conductivity, improve motor efficiency, improve the rigidity of the product itself, and at the same time, NVH can also be greatly improved. So what is the self-bonded motor lamination stacks? How is it different from bonded iron core?

Lamination Glue Bonding Process

The bonded lamination core is bonded with glue to replace the traditional welding and stack riveting methods. The purpose of improvement through this method is to improve the electric magnetic properties of the motor and reduce the iron damage of the stator and rotor lamination stacks.

Self-Adhesive Laminations Process

The self-bonded lamination is actually a type of bonded iron core. It means that the motor punched sheets are fixed on the entire surface of the iron core with self-adhesive fixed core laminations, which greatly improves the fixing strength of the iron core.

The principle of self-bonding iron core lies in the coating of silicon steel laminations. However, compared with ordinary electrical steel sheets, self-bonding iron cores add a coating containing glue components(such as bonding varnish) to silicon steel sheets, which is non-sticky at room temperature. , after the iron core is manufactured, under specific conditions of pressure and temperature, the glue is melted and then solidified to bond the iron core into one body.

lamination stacks bonding and stacking

Advantages Of Self-bonding Process

Self bonding rotor lamination stacks offer numerous advantages over traditional methods. They provide greater stability, reducing eddy current losses and minimizing vibrations during high-speed operation, thus enhancing overall motor efficiency and NVH characteristics.

Moreover, self-bonding eliminates the need for additional components like end plates and fasteners, optimizing space utilization within the motor.

Performance Comparison

Compared with the welded lamination core, the magnetic results of the self-bonded iron core tested at a magnetic induction intensity of 1.5T and 50Hz showed that the core loss was reduced by about 5% and the excitation current was reduced by 9%.

Core Loss

The noise generated by the self-bonded lamination stacks is about 5dB lower than that of the welded core when the magnetic induction intensity is the same.

Eddy Current Loss

Under the same test conditions, regarding the axial vibration speed of the core under excitation, the self-bonded core has almost no vibration, while the welded core has varying degrees of vibration. The radial vibration test of the stator core has the same results.

EVs Thin Silicon Steel Laminations

One of the primary challenges in electric vehicles’ rotor core design is reducing iron losses, particularly in thin silicon steel laminations. Conventional bonding methods struggle with assembling these ultra-thin laminations effectively.

Laser welding, for example, can lead to localized conductivity issues, adversely affecting motor performance. Ultra-thin silicon steel sheets make it difficult to form riveting points. Self-bonding rotor cores offer a solution to this challenge, enabling the assembly of thin laminates without compromising performance.


In the quest for high-performance electric motors, the significance of rotor core technology cannot be overstated. Self bonding rotor lamination stacks represent a significant advancement over traditional bonding methods, offering superior performance, efficiency, and NVH characteristics.

As the demand for compact, efficient electric motors continues to rise, self-bonding technology is poised to play a pivotal role in shaping the future of electric mobility.

Lamnow – Self Bonding Motor Laminations Manufacturer

Lamnow bonding solutions, including glue dot bonding and self-bonding processes, ensure superior performance and efficiency in electric motors, generators, and transformers. In addition, we excel in bonding segmented stator laminations, offering precise and reliable bonding for various applications.

Our bonding laminations find extensive use in automotive motors, particularly electric vehicles, where efficiency and reliability are paramount. Additionally, our laminations cater to hub motors, drone motors, washing machine motors, transformer cores, and linear motors, providing versatile solutions for diverse industries.

At Lamnow, we are committed to delivering high-quality products that meet the evolving needs of the electric mobility sector and other industries.  If you need motor lamination packs, contact us now.

self bonding motor lamination in NEVs


What is glue dot bonding, and how does it work?

Glue dot bonding involves applying small adhesive dots to laminations, which then bond together under pressure and heat. This method provides precise and uniform bonding, ensuring optimal motor performance.

How does self-bonding differ from traditional adhesive bonding?

Self-bonding involves integrating adhesive materials into the laminations themselves, enabling bonding to occur during the manufacturing process without the need for additional adhesives. This results in a seamless and durable bond.

Can bonding laminations be used for segmented stators in electric motors?

Yes, bonding laminations can be used for segmented stators, providing precise bonding between individual segments to create a unified stator assembly.

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To learn more about our motor lamination manufacturing capabilities for your industry, contact our team today.