Lamination punching
The Lamination Punching Process — The Backbone of Motor and Generator Manufacturing Ask anyone who works in electric motor or transformer manufacturing, and they’ll tell you — the magic is in the details. One of the most important (yet often behind-the-scenes) processes in building electric motors, transformers, and generators is lamination punching. It’s a craft in its own right, using carefully designed steel or carbide punches and dies to cut thin sheets of electrical steel into precise shapes. These thin pieces, called laminations, are then stacked together to form the building blocks of components like the motor lamination stack, stator lamination set, stator core, rotor core, and rotor lamination assembly. Without getting this step right, the performance, efficiency, and lifespan of electric machines would suffer — plain and simple.
What Are Motor Laminations, and Why Are They So Important?
Inside every electric motor, there’s a motor core built from dozens, sometimes hundreds, of these thin steel sheets — motor laminations. Why not use solid steel? Well, that would allow for energy-wasting eddy currents and unwanted heat buildup. Instead, manufacturers punch these laminations into highly precise shapes and then stack them to create a core that keeps energy losses to a minimum. But this isn’t something you can afford to eyeball.
If the thickness, slot placement, or alignment is off even slightly, the motor can end up noisy, unbalanced, or inefficient. That’s why manufacturers put enormous effort into tool design. The punches and dies need to be sharp, accurate, and consistent — because every lamination needs to be perfect.
Rotor Laminations and Rotor Cores: Built to Move, Built to Last
While the stator sits still, the rotor turns — and it, too, depends on precise lamination punching. Rotor laminations are punched with slots that house conductive bars or coils. The shape, size, and position of these slots are critical to the rotor’s ability to generate torque and maintain smooth rotation.