There are two method of bolts detection: manual and machine. Manual is the most primitive and most commonly used consistent detection method. In order to minimize the outflow of defective products, the general production company personnel inspect the packaged or shipped products by visual inspection to eliminate defective products (defects include thread injuries, mixing, rust, etc.).
The other method is automatic machine inspection, mainly magnetic particle inspection. Magnetic particle inspection is a product of magnetization testing. If the product has defects (such as cracks, slag inclusions, mixing, etc.), Leakage magnetic field will be generated during magnetization, thereby attracting the accumulation of magnetic particles at the defects formed by the magnetic particles—magnetic marks. Under the bright light conditions, the defect location and shape appear. Observing and explaining the accumulation of these magnetic powders has achieved the purpose of eliminating defective products.
