What kinds of bolt detection are there for small hardware accessories? There are two types of bolt detection: manual and machine. Manual is the most primitive and the most commonly used consistent detection method. In order to minimize the outflow of defective products, general production enterprise personnel inspect the packaged or shipped products by visual means to exclude defective products (defects include tooth damage, mixed materials, rust, etc.).

Another method is automatic inspection by machine, mainly magnetic particle inspection. Magnetic particle inspection is to use the interaction between the leakage magnetic field at the defect of the bolt and the magnetic powder, aiming at the difference between the magnetic permeability of the bolt and the magnetic permeability of the steel that may exist in the defect (such as crack, slag inclusion, mixed material, etc.).

After magnetization, the magnetic field at the discontinuity of these materials will change, and a leakage magnetic field will be generated on the surface of the workpiece where part of the magnetic flux leaks, thereby attracting the magnetic powder to form the magnetic powder accumulation at the defect— - Magnetic traces, under appropriate lighting conditions, show the position and shape of defects, observe and explain the accumulation of these magnetic powders, and have achieved the purpose of rejecting defective products.