Core Lamination

A core lamination is a thin sheet of electrical steel used in the construction of transformer cores, motor cores, and other electrical devices. These laminations are typically made from cold-rolled, grain-oriented silicon steel, which has excellent magnetic properties. Core laminations are typically manufactured in various shapes and sizes to fit the specific needs of the application, and they are often coated with an insulating material to further reduce eddy current losses. The laminations are stacked together to form the core, and the gaps between the laminations are filled with an insulating material. Core lamination is an important technology that is used to improve the efficiency and performance of electrical devices to save energy and reduce operating costs.

 

Description

 

The primary purpose of core lamination is to reduce eddy current which is circular current that flows within the core due to the changing magnetic field, and this current generates heat and waste energy. By laminating the core, the eddy current paths are interrupted, and it can ultimately reduce the magnitude of the currents and the associated losses. Although the manufacturing process for core laminations is more complex than for solid cores, the benefits of reduced losses, improved performance, and weight reduction often outweigh the additional cost. Core lamination is used to improve the efficiency, performance, and overall functionality of electrical devices by reducing eddy current losses, improving magnetic properties, reducing weight and size, enhancing heat dissipation, and minimizing noise. Because of its special property, electric motors generally designed to have a stator, an outer lamination, and a rotor, an inner lamination. The stator acts as a stationary part of the motor which provides support and contains key parts like windings that create a magnetic field when the current is applied. While the rotor is located inside the stator and is responsible for creating motion with the help of magnets fixed onto its surface. When a voltage supply is connected, the rotor moves within these magnetic fields converting electrical energy into mechanical energy.

What are the materials used for core?

Most electromagnet takes advantage of a core which is a kind of ferromagnetic or ferrimagnetic metal component around which the electric wires are wound to achieve higher magnetic field output. The logic behind the core can be readily explained by the Ampére's circuital law. Ampére's circuital law relates the integrated magnetic field around a closed loop to the electric current passing through the loop. Meanwhile permeability is a crucial property of the core material in electromagnets because it affects the strength of the magnetic field generated by electromagnets. The below table includes permeability values of some common materials, and it's only used with caution because permeability varies greatly with field strength.

 Core Lamination Asseembly

Core lamination has very unique features, and they make the core lamination very deal for applications with limited installation space or when existing laminations need to be replaced without disrupting ongoing operations. To ensure optimal performance of your electric motor, Fabmann uses few popular metals below:

√ Silicon Steel, it is the most common lamination material for motor cores. It offers high electrical conductivity, low hysteresis loss, excellent corrosion resistance, and relatively low cost. Alongside its strong structural integrity, offering long-lasting performance assurances even under extreme physical stress environments. Silicon steel also offers good shielding properties against electromagnetic interference. Therefore, it is useful in equipment where the radiation needs minimizing, such as medical instrumentation or transport systems like railroads.

√ Nickle alloys, they come with higher heat resistance than silicon steel, and they are ideal for applications such as rotary converters, which must resist high temperatures over long periods.

√ Cobalt alloys, also called cobalt-iron alloys, they offer a number of benefits when used in stamped components, including improved resistance to corrosion, heat, and wear, plus, they have a much higher magnetic permeability than either nickel or silicon steel. Therefore, it is especially well-suited for large DC machines due to their tolerance against eddy current losses in winding coils.

√ Thin-gauge electrical steels, they are ideal for applications with high performance and energy-efficiency requirements, and they are easy to assemble because their sheets can be easily laminated onto existing laminations using epoxy adhesives.

Our capabilities are listed as follows:

√Cobalt-iron alloys, 0.1-1.0mm

√Nickel alloy, 0.1-0.50mm

√Silicon steel, 0.3-0.65mm

√Thin-gauge electrical steel, 0.075-0.25mm

 

What are the advantages of core lamination?

 

Stacked and tightly connected laminations is called a laminated core, or stator core or rotor core. To produce these packets, also known as cores or magnetic cores, individual laminations of sheet metal are stacked on top of each other, precisely aligned and baked into a packet, or joined by another packaging step. These stacks of laminations are also referred to as lamination stacks or simply as a stack of laminations. Stacked laminations are used as magnetic cores in electrical machines and are, among other things, a component of every electric motor. Electrical steel strip or electrical sheet is an iron-silicon alloy with special magnetic properties that are particularly suitable for use in electric motors. Due to these special properties, the targeted use of laminations made of electrical steel sheet for the production of magnetic or iron cores leads to a significantly improved energy efficiency or high efficiency of electrical systems and thus to a sustainable and optimal use of the required resources.

 

√ Reduced eddy current losses, the main advantage of core lamination is the reduction of eddy current losses. This leads to increased efficiency and reduced operating costs.

√ Improved magnetic properties, the of grain-oriented silicon steel provides excellent magnetic properties, such as high permeability and low hysteresis loss.

√ Reduced weight and size, the core can be made lighter and smaller, which is important for applications where weight and space are limited.

√ High permeability allows the core to easily conduct magnetic flux, which improves the performance of the device.

√ Low hysteresis loss reduces the energy lost due to the magnetization and demagnetization of the core material.

√ Improved heat dissipation, the gaps between the laminations provide channels for air circulation, which improves heat dissipation from the core. This helps to prevent overheating and maintain the performance of the device.

√ Reduced noise, the reduced eddy currents can make audible noise.

√ Cost-Effectiveness, although the manufacturing process for core laminations is more complex than for solid cores, the benefits of reduced losses, improved performance, and weight reduction often outweigh the additional cost.

 

In short, core lamination is used to improve the efficiency, performance, and overall functionality of electrical devices by reducing eddy current losses, improving magnetic properties, reducing weight and size, enhancing heat dissipation, and minimizing noise. The steel core is used to amplify the magnetic flux generated by the electric current passing through the coils, and the optimized magnetic properties of the steel core in all directions is achieved so that minimum energy losses and maximum efficiency can be achieved. 

 

What are the applications of core lamination?

 

Core laminations are used in a wide variety of electrical devices, including:

 

√ Transformers use core laminations to increase their efficiency and reduce losses.

√ Motors use core laminations to improve their performance and reduce noise.

√ Generators use core laminations to increase their output and reduce losses.

√ Inductors use core laminations to increase their inductance and reduce losses.

 

 

How does Fabmann make core lamination?

Fabmann always put client's requirement as first priority, and therefore our starting point is always clarifying requirements. Our engineering team and tooling experts will work with you to understand product requirements, and then prepare preliminary tooling concepts. After collaborating on custom tooling designs, our team will conduct rigorous testing, validate those designs with the engineering team, and make optimization adjustments to your designs for optimized performance. Once the design is complete, we send the product drawings to our experienced tooling experts and begin manufacturing the final product. The production of the verified design covers following steps:

√ Steel material preparation

√ Electrical steel punching production, the stamped laminations are cured using an adhesive that is applied through heat and pressure. This process produces cores with good dimensional properties, structural integrity and interlaminar sealing to prevent leaks in liquid cooling applications.

√ Welding, our welding specialists (MIG, TIG, and Laser Welding solutions) can turn electrical steel laminations, stacked core segments and integral stacked cores into strong, reliable one-piece cores.

√ Adding ventilation, our expert operators can even add venting laminations to larger cores to improve motor cooling.

√ Full surface bonding, after stamping, the core is fixed and the adhesive is cured through heat and pressure. The resulting core exhibits unparalleled dimensional properties, structural integrity, and features interlayer sealing to prevent leakage in liquid cooling applications.

√ In-mold bonding, glue is applied as the strip passes through the die, and the glue bonds the pieces together as they are punched out of the strip.

√ Assembly

√ Quality check & test, after the full assembly, our testing engineers will do following controls:

1. 1. Dimension
2. 2. Electrical connection test
3. 3. Magnetic test

Core Lamination Dimension Inspection

As you can see, Fabmann offers in-house annealing, grinding, assembly, and other post-stamping services to ensure one-stop service for custom core lamination, and our custom fabrication includes bonding, welding, riveting, stacking and assembly. Our cost-effective assembly process can meet the requirements of a variety of design functions, including rotation and multi-geometry laminations, and our experienced engineers will work around the clock for your orders.