Bolt Inspection

 

Bolt inspection can be divided into two types: manual and machine. Manual is the most primitive and most commonly used consistent inspection method. In order to minimize the outflow of defective products, general production enterprise personnel visually inspect the products to be packaged or shipped to eliminate defective products (defective products include tooth damage, mixed materials, rust, etc.). [2]
Another method is fully automatic inspection by machine, mainly magnetic particle inspection. Magnetic particle inspection uses the interaction between the leakage magnetic field at the bolt defect and the magnetic powder. According to the difference in magnetic permeability of the possible defects (such as cracks, slag inclusions, mixed materials, etc.) of the bolt and the magnetic permeability of steel, the magnetic field at the discontinuity of these materials will be distorted after magnetization, forming a leakage magnetic field on the surface of the workpiece where some magnetic flux leaks, thereby attracting magnetic powder to form magnetic powder accumulation at the defect - magnetic trace. Under appropriate lighting conditions, the defect position and shape are revealed. The accumulation of these magnetic powders is observed and interpreted to achieve the purpose of eliminating defective products.