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Laminated steel plates , also known as laminations, are thin sheets of electrical steel stacked together to form the magnetic core of the rotor and stator. Rather than using a single solid piece of steel, electric motors rely on multiple thin layers, carefully stacked to achieve the desired magnetic and electrical properties.
When an electric motor operates, the alternating magnetic field generates electrical currents within the steel core. These currents, known as eddy currents, can lead to unwanted energy losses and heat generation. By dividing the core into thin, electrically insulated laminations, these currents are significantly reduced, helping to minimize energy losses and improve the overall efficiency of the motor.
However, using individual laminations also introduces an important assembly challenge : the plates must remain securely aligned and bonded together throughout the motor's operation. The laminated stack is exposed to mechanical stresses, vibrations and temperature variations, making reliable assembly essential for maintaining the structural integrity and performance of the motor.
This is where the bonding method becomes a key consideration. While traditional mechanical assembly methods can be used to hold the laminations together, adhesive bonding offers an alternative approach that can provide both structural integrity and additional manufacturing benefits.
Traditionally, laminated steel plates can be assembled using mechanical methods such as welding, riveting or interlocking. While these techniques can provide reliable assembly, they may also introduce certain limitations, particularly as electric motor designs become increasingly compact and performance requirements become more demanding.
Adhesive bonding offers several advantages. Unlike mechanical fastening, which concentrates forces at specific points or areas, an adhesive can distribute the load more evenly across the bonded surface, resulting in a price decrease and a better sealing. This also helps reduce localized mechanical stresses and contributes to the overall structural integrity of the laminated stack.
Another advantage is the absence of heat during the bonding process. Welding can generate localized heat that may lead to thermal deformation or affect the properties of the laminated steel. Adhesive bonding, particularly when using anaerobic adhesives, by contrast, can be performed without introducing the same level of thermal stress, helping to preserve the dimensional accuracy of the stack.
From a manufacturing perspective, adhesive bonding can also be integrated into automated production processes. Depending on the adhesive and application method, precise and repeatable dispensing can be incorporated into high-volume manufacturing lines, helping manufacturers achieve consistent bonding performance while optimizing production efficiency.
Finally, by improving the overall rigidity of the stack and reducing relative movement between individual laminations, adhesive bonding can help reduce vibration and contribute to lower operating , depending on the motor design and application.
It is for all those reasons, that adhesive bonding can be considered as an entire sealing method instead of mechanical assembly processes inside electric motors.
To bond laminated steel plates, adhesive must be applied between the individual laminations. Several application processes exist, such as bead, dot, or coating application, depending on the assembly method, dispensing equipment, and the manufacturer's requirements.
Once the adhesive has been applied and the laminations assembled, the curing process will depend on the type of adhesive used. Anaerobic adhesives, for example, do not require any specific curing equipment. They cure in the absence of air and in the presence of metal ions, meaning that simply pressing the laminated plates together can initiate the curing process.
Other solutions, such as heat-curing epoxy resins, require a controlled heating process to reach their final properties. Although they may require additional equipment and longer curing times, epoxy adhesives can offer excellent adhesion, mechanical strength, and sealing properties.
Finally, selecting the right adhesive requires consideration of several parameters, including viscosity, curing speed, temperature resistance, mechanical strength, and application method. These properties allow adhesive solutions to be adapted and optimized according to the specific requirements of each manufacturer and motor design.
ThreeBond offers a wide range of adhesive solutions for bonding and sealing laminated steel plates. Among these solutions, anaerobic adhesives are particularly well suited to applications where the laminations need to be securely assembled while maintaining an efficient and straightforward manufacturing process.
Anaerobic adhesives cure when they are confined between metal surfaces and exposed to metal ions, while oxygen is excluded from the bonded area. This makes them especially suitable for laminated steel stacks, where the adhesive is applied between closely assembled metal surfaces. Once the laminations are pressed together, curing can take place directly within the bonded area without the need for additional heat or specialized curing equipment.
Depending on the application, ThreeBond anaerobic adhesives are available in different viscosities and performance levels, allowing manufacturers to select the most suitable solution for their dispensing process and assembly requirements. The adhesive can be applied as a bead or in specific areas of the lamination, providing reliable bonding while also helping to seal the assembly. We also propose heat curing epoxy adhesives for those specific applications just like TB2287 series.
Beyond their ease of application, anaerobic adhesives can offer excellent adhesion to metal substrates, mechanical strength, resistance to vibration, and temperature resistance. These properties make them suitable for demanding electric motor applications, where the laminated stack is continuously exposed to mechanical and thermal stresses.
By combining different adhesive technologies, viscosities, and curing characteristics, ThreeBond can provide solutions tailored to the specific requirements of each motor design and manufacturing process.
Electric Motor Stack Bonding : the role of adhesives in laminated steel stacks
14/09/2026
Inside every electric motor are two essential components: the rotor and the stator. At the core of both lies a stack of thin laminated steel plates, carefully assembled to optimize motor efficiency and performance.
At ThreeBond, we develop adhesive solutions designed to address a wide range of challenges inside electric motors. From electronic components such as PCBs and chip bonding to glob top encapsulation, magnet bonding, and laminated steel plate bonding, our adhesives support manufacturers throughout the motor assembly process.
But how are these laminations held together ? And why is adhesive bonding becoming an attractive alternative to traditional mechanical assembly methods ?
At ThreeBond, we develop adhesive solutions designed to address a wide range of challenges inside electric motors. From electronic components such as PCBs and chip bonding to glob top encapsulation, magnet bonding, and laminated steel plate bonding, our adhesives support manufacturers throughout the motor assembly process.
01. Laminated Steel Plates : why are they used ?
When an electric motor operates, the alternating magnetic field generates electrical currents within the steel core. These currents, known as eddy currents, can lead to unwanted energy losses and heat generation. By dividing the core into thin, electrically insulated laminations, these currents are significantly reduced, helping to minimize energy losses and improve the overall efficiency of the motor.
However, using individual laminations also introduces an important assembly challenge : the plates must remain securely aligned and bonded together throughout the motor's operation. The laminated stack is exposed to mechanical stresses, vibrations and temperature variations, making reliable assembly essential for maintaining the structural integrity and performance of the motor.
This is where the bonding method becomes a key consideration. While traditional mechanical assembly methods can be used to hold the laminations together, adhesive bonding offers an alternative approach that can provide both structural integrity and additional manufacturing benefits.
02. Why use adhesive bonding instead of mechanical bonding ?
Traditionally, laminated steel plates can be assembled using mechanical methods such as welding, riveting or interlocking. While these techniques can provide reliable assembly, they may also introduce certain limitations, particularly as electric motor designs become increasingly compact and performance requirements become more demanding.
Adhesive bonding offers several advantages. Unlike mechanical fastening, which concentrates forces at specific points or areas, an adhesive can distribute the load more evenly across the bonded surface, resulting in a price decrease and a better sealing. This also helps reduce localized mechanical stresses and contributes to the overall structural integrity of the laminated stack.
Another advantage is the absence of heat during the bonding process. Welding can generate localized heat that may lead to thermal deformation or affect the properties of the laminated steel. Adhesive bonding, particularly when using anaerobic adhesives, by contrast, can be performed without introducing the same level of thermal stress, helping to preserve the dimensional accuracy of the stack.
From a manufacturing perspective, adhesive bonding can also be integrated into automated production processes. Depending on the adhesive and application method, precise and repeatable dispensing can be incorporated into high-volume manufacturing lines, helping manufacturers achieve consistent bonding performance while optimizing production efficiency.
Finally, by improving the overall rigidity of the stack and reducing relative movement between individual laminations, adhesive bonding can help reduce vibration and contribute to lower operating , depending on the motor design and application.
It is for all those reasons, that adhesive bonding can be considered as an entire sealing method instead of mechanical assembly processes inside electric motors.
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03. How to Bond Laminated Steel Plates ?
To bond laminated steel plates, adhesive must be applied between the individual laminations. Several application processes exist, such as bead, dot, or coating application, depending on the assembly method, dispensing equipment, and the manufacturer's requirements.
Bead application consists of dispensing adhesive along the edges of the laminations, helping to securely hold the plates together while providing additional sealing.
Dot application, on the other hand, consists of applying the adhesive in small dots at strategic locations on the lamination. This method allows the adhesive to be precisely positioned while limiting the amount of product used.
Coating consists of applying a thin, continuous layer of adhesive over the entire surface of the lamination, providing a larger bonding area and a more uniform distribution of the adhesive.
Once the adhesive has been applied and the laminations assembled, the curing process will depend on the type of adhesive used. Anaerobic adhesives, for example, do not require any specific curing equipment. They cure in the absence of air and in the presence of metal ions, meaning that simply pressing the laminated plates together can initiate the curing process.
Other solutions, such as heat-curing epoxy resins, require a controlled heating process to reach their final properties. Although they may require additional equipment and longer curing times, epoxy adhesives can offer excellent adhesion, mechanical strength, and sealing properties.
Finally, selecting the right adhesive requires consideration of several parameters, including viscosity, curing speed, temperature resistance, mechanical strength, and application method. These properties allow adhesive solutions to be adapted and optimized according to the specific requirements of each manufacturer and motor design.
04. ThreeBond solutions for electric motor stack bonding
ThreeBond offers a wide range of adhesive solutions for bonding and sealing laminated steel plates. Among these solutions, anaerobic adhesives are particularly well suited to applications where the laminations need to be securely assembled while maintaining an efficient and straightforward manufacturing process.
Depending on the application, ThreeBond anaerobic adhesives are available in different viscosities and performance levels, allowing manufacturers to select the most suitable solution for their dispensing process and assembly requirements. The adhesive can be applied as a bead or in specific areas of the lamination, providing reliable bonding while also helping to seal the assembly. We also propose heat curing epoxy adhesives for those specific applications just like TB2287 series.
TB1357K
Acrylate anaerobic adhesive
- High strength
- Heat resistant
- Low halogen
- Bonding of metallic part fitting areas
- Laminated core bonding
- Bearing fixing
- Laminated core bonding
- Magnet bonding
Viscosity12 Pa･s
ColourBlue
Service temperature-40 to +175°C
TB1360F
Acrylate anaerobic adhesive
- High temperature resistance
- Fast curing
- Threadlocker
- Laminated core bonding
Viscosity500 mPa･s
ColourGreen
Service temperature-40 to +200°C
TB1360G
Acrylate anaerobic adhesive
- High strength
- High heat resistant
- Provided with axial force
- Laminated core bonding
Viscosity1.8 Pa･s
ColourBlue
Service temperature-40 to +200°C
TB2287F
Heat curing epoxy resin
- High strength
- High heat resistant
- Provided with axial force
- Laminated core bonding
Viscosity150 Pa･s
ColourReddish brown
Service temperature-40 to +150°C
Beyond their ease of application, anaerobic adhesives can offer excellent adhesion to metal substrates, mechanical strength, resistance to vibration, and temperature resistance. These properties make them suitable for demanding electric motor applications, where the laminated stack is continuously exposed to mechanical and thermal stresses.
By combining different adhesive technologies, viscosities, and curing characteristics, ThreeBond can provide solutions tailored to the specific requirements of each motor design and manufacturing process.
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