What is the principle behind electromagnetic clamping fixtures?

What is the principle behind electromagnetic permanent magnet clamping fixtures? Electromagnetic permanent magnet clamping fixtures are a clamping system that combines the advantages of electromagnets and permanent magnets, utilizing the switching between electromagnetic and permanent magnetism to achieve reliable and efficient workpiece fixation. Its working principle can be divided into three stages:

1. Magnetization Stage: When the clamping needs to be activated, a brief electrical current (ranging from a few milliseconds to a few seconds) is passed through the coil to generate an electromagnetic field, magnetizing the internal neodymium-iron-boron permanent magnet materials to reach a magnetic saturation state. At this point, the permanent magnet materials produce a strong magnetic field, attracting the workpiece through the working surface of the fixture, thus securing the workpiece.

2. Clamping Phase: After magnetization is completed, even if the power is disconnected, the permanent magnet retains its magnetism. Therefore, the electro-permanent magnet fixture can maintain long-term stable clamping without continuous power supply. This reduces energy consumption and heat generation, and also minimizes the risk of workpiece drop due to power failure or electromagnetic coil failure.

During the degaussing phase, when it is necessary to loosen parts, a brief reconnection of power is used to pass current through the reverse coil, creating a magnetic field in the opposite direction of magnetization. This partially counters the magnetic force within the permanent magnet, reducing the magnetic attraction, making it easier to remove the parts.

Electromagnetic clamps offer the following advantages: high efficiency and energy-saving, consuming electricity only during magnetization and demagnetization, and no power supply is needed at other times. They are safe and reliable, maintaining clamping force even after power failure, preventing workpiece detachment due to unexpected power outages. Operation is simple, with the magnetization and demagnetization process requiring only a short time, and the operation is straightforward with rapid response. The clamping force is uniform, with the magnetic force evenly distributed across the entire clamping surface, reducing workpiece deformation and improving processing accuracy.

Electromagnetic clamping fixtures are widely used in various mechanical processing, mold manufacturing, metal cutting, electrical discharge machining, and measuring devices. They are particularly suitable for applications requiring quick workpiece changeovers and high-precision processing.