Magnetic particle inspection (MPI) equipment for non-destructive testing, in this section, we will guide you through the key points of knowledge regarding the magnetic particle inspection machine. With this article, you should be able to understand its use of the MPI machine, recognize the maintenance skills of the MPI, and how the instrument detects defects when the workpiece is magnetized. If there are defects on the surface of the workpiece, the magnetic flux leakage occurs due to the increased magnetic resistance at the defect location, creating a local magnetic field. The magnetic particles then reveal the shape and position of the defects, thereby determining the presence of the defects. MPI machines can be categorized based on the different magnetizing currents used: DC magnetization, half-wave DC magnetization, and AC magnetization.
Applications of the Magnetic Particle Inspection Machine.
Magnetic Particle Inspection MachineThe system can display component parts, welding surfaces, and internal defects, ultimately determining the quality of the workpiece.
The application, which displays discontinuous workpiece positions, shapes, and dimensions.
Application Two: The magnetic particle inspection machine boasts high detection sensitivity, allowing for the direct visualization of the location, shape, size, and severity of defects in the inspected workpiece. It excels in identifying the repeatability of defects.
Application three: Magnetic particle inspection is widely used in pipes, bars, shapes, weldments, fittings, and forgings.
The Magnetic Particle Inspection (MPI) equipment can be categorized based on different measurement principles, including digital ultrasonic flaw detectors, ultrasonic flaw detectors, MPI, eddy current flaw detectors, X-ray flaw detectors, and fluorescent flaw detectors. They are primarily used for detecting internal defects (such as cracks, sand holes, blow holes, white spots, inclusions, etc.) in machined parts, assessing the quality of welds, identifying hidden defects, and determining the qualification of workpieces.
A portion of the coated surface of the object.
Due to the inspection of components involving certain parts on the surface, including paint, layered silicates, enamels, and other coatings, as well as oxide layers, various deposits (carbon, impurities, dirt), mechanical layer damage, erosion, and other injuries, extensive preparation is required prior to magnetic particle inspection. The workload can be substantial, sometimes involving the opening and removal of protective layers or dirt.
It is particularly important to note that as the thickness of the non-magnetic coating on the part surface exceeds 30μm, the sensitivity of the magnetic particle inspection (MPI) device will significantly decrease. This is due to the sensitive reduction in magnetic field strength above the defect as it moves away from the part surface. At a distance of 100μm from the surface, the attractive force on the particles becomes so small that they no longer attract the defect. Therefore, if the paint layer thickness exceeds 30μm, the paint layer on the inspected surface must be removed prior to magnetic particle inspection.
(2) The initial defect was identified as a crack.
The primary purpose of magnetic particle inspection is to detect cracks in parts during the application process, as the attacked areas of cracks are located at critical stress assembly positions, meaning the crack locations are regular...
Therefore, in aviation maintenance, magnetic particle inspection is generally not a 100% check of the parts but involves inspecting certain critical areas of the parts. This is why it is crucial for inspectors to have a thorough understanding of the failure patterns, locations, and directions of cracks in the inspected parts before choosing an appropriate magnetization method to achieve reliable inspection results.