olt detection is divided into two types: artificial and machine. Manual is the most primitive and most commonly used consistent detection method. In order to minimize the outflow of undesirable products, general production enterprise personnel through the visual manner of the packaging or delivery of products to carry out inspection to exclude undesirable products (including tooth injury, mixed materials, rust, etc.).
Another way for machine automatic detection, mainly magnetic particle flaw detection.
Magnetic particle flaw detection is the use of the bolt defects in the magnetic leakage and magnetic particle interaction, for the bolts may exist defects (such as cracks, slag, mixing, etc.) permeability and steel permeability differences, after magnetization of these materials discontinuity of the magnetic field will occur in the transformation, forming part of the magnetic flux leakage of the workpiece surface produced a leakage magnetic field, so as to attract magnetic powder formation defects of the magnetic powder accumulation-magnetic trace, in the appropriate light conditions, showing the location and shape of defects, the accumulation of these particles to observe and explain, has achieved the purpose of excluding undesirable products.