Non Destructive Testing (NDT) is the examination of parts and materials to identify defects or cracks that may lead to the subsequent failure of the part, in a way that does not change or destroy the part during the inspection process.
The two primary methods of Non Destructive Testing that we use are:-
Magnetic Particle Inspection (MPI)
This method is used to find surface and near surface cracks and dis-continuities in ferromagnetic materials such as steel and iron. MPI works by covering the part with a fluid that contains very small fluorescent magnetic particles and then either creating a strong magnetic field in or around the part.
If there are any cracks, the cracks create a discontinuity in the magnetic field to with the fluorescent particles are attracted to, and when examined under ultra violet light ( black light ) will fluoresce brightly showing the location and size of the crack or defect.
During engine overhaul, the crankshaft, connecting rods, gears, rocker arm, and all other major steel parts in your engine are inspected using the Magnetic Particle Technique.
Fluorescent Dye Penetrant
This method is used to find surface cracks in mainly aluminium components. Essential this method involves covering the part to be inspected with a special fluorescent dye.
If a surface crack or defect is present, some of the fluorescent dye penetrates into and is held in the crack. The part is then carefully washed to remove the excess fluorescent dye from the surface of the part and allowed to dry before a developer is applied.
The developer helps to draw out some of the fluorescent dye that was held in the crack back to the surface of the part.
The next step is to examine the part under a ultra violet light (referred to as a black light) and if a crack or defect is present, it can be identified as any dye that has bleed back to the surface will fluoresce brightly and show the location and extent of the crack or defect.