Types of Magnetic Chucks: Permanent and Electromagnetic
There are two types of magnetic chucks: Permanent Magnetic Chucks and Electromagnetic Chucks, as shown in (Figure 1) and (Figure 2):
(Figure 1) Permanent Magnetic Chuck
(Figure 2) Electromagnetic Chuck
Permanent Magnetic Chucks
When the hex wrench is turned to the "ON" position, the magnet base aligns with the magnetic conductive work faceplate. As a result, the magnetic force follows the path of least reluctance to form an open circuit through the workpiece, completing the magnetic circuit and clamping the workpiece firmly. When the hex wrench is turned to the "OFF" position, the magnetic poles circulate internally within the chuck, leaving the surface non-magnetic.
Electromagnetic Chucks
In an electromagnetic chuck, a magnetic field is generated by the induction of the coil poles when direct current (DC) passes through, which adsorbs the workpiece. Rectangular magnetic chucks are mostly used for grinding or milling machines where the grinding wheel or cutter head moves reciprocally (left and right). Round magnetic chucks are utilized for lathes involved in circular rotational processing.
Demagnetization (Degaussing)
Using permanent or electromagnetic chucks for clamping workpieces is efficient and convenient. However, after the grinding process is completed, workpieces often retain residual magnetism, which can be detrimental to the workpiece's performance. Therefore, demagnetization (degaussing) is required.
For DC electromagnetic chucks, demagnetization can be achieved by reversing the current direction. This process can be performed using a Magnetic Chuck Controller with a demagnetization function (Figure 3) or by using a Demagnetizer as shown in (Figure 4).
(Figure 3) Magnetic Chuck Controller
(Figure 4) Demagnetizer