Magnetic chuck how does it work

For example a lapped fine finished product will have an micron finished even surface and have the best workholding properties, whereas a rough planed surface will have a much poorer holding force due to air gaps prevalent in the uneven surface.

Materials Type and Configuration The material type determines the magnetic clamping force. Some materials have less magnetic permeability and this will affect the hold. The chart below shows some examples of how the clamping force is affected by different material types.

Material, hardness, shape and flatness of the workpiece material. Material Thickness Thinner materials are less absorbent of magnetic flux. The flux path within a workpiece is a semi-circle from the centre of one chuck pole to the centre of the next.

If the workpiece is thinner than this radius it cannot absorb all the flux and some passes through. The resultant pull is lower than that of a thicker workpiece when all the flux is fully absorbed. This means the hold is greater. The disadvantage of this chuck is that it releases the part when the electrical current is stopped, often putting the worker at risk of injury if it happens during a work process. Electro-permanent magnetic chuck — a hybrid of the permanent and electromagnetic type.

This device locks the part with a jolt of electricity and then uses another jolt of electricity to unlock it. If there is a power outage while working a part, the chuck continues to hold tightly.

Each magnet has an electrical coil around it that can reverse the polarity of the magnet extremely quickly. Another function of the coil is to control the amount of magnetic pull the magnetic chuck exerts. Tweet on Twitter Share on Facebook Pinterest. You May Also Like. Using electromagnetic, electro-permanent and permanent magnetic chucks for clamping and unclamping of the machined components saves time, allows the workpiece to be accessible from 5 sides, and the chuck does not damage the product.

The use of magnetic chucks for workholding has become a popular option in manufacturing facilities across the country. The goal is simple. Hold the blank, casting, or forging to be machined with enough grip to allow milling, turning, drilling, or grinding. Traditionally, workpieces for machining were held in place using vises or fixtures.

While magnetic chucks have been an accepted method of workholding in surface grinding applications, they are now finding acceptance in general machine shops. Magnetic chucks reduce setup, increase access to the many sides of a workpiece, and simplify workholding.

A key advantage of magnetic chucks for workholding is consistent clamping. Unlike mechanical clamps and vises, there are no variations on how tightly the workpiece is held. Full support of the workpiece is another advantage. For example, if toe clamps are used on the outer surfaces of a workpiece, the center of the piece is a challenge. These unsupported areas can chatter resulting in increased cycle time. Workholding chucks hold the whole workpiece.