What is the importance of surface preparation before MPI?

Surface preparation is a critical step in the Magnetic Particle Inspection (MPI) process because it directly impacts the effectiveness of defect detection. When a surface is properly cleaned and prepared, it allows for better adherence of the magnetic particles to the material being inspected. Any contaminants such as dirt, oil, paint, or rust can prevent the magnetic particles from correctly accumulating at the site of a defect, leading to inaccurate results or missed indications.

By ensuring that the surface is free of these obstacles, the visibility of any defects, such as cracks or inclusions, is significantly enhanced. This not only improves the reliability of the inspection results but also boosts the overall accuracy, as the clearer the defect indicators are, the easier it is for the inspector to identify and assess them. Therefore, thorough surface preparation is essential to achieving the full potential of the MPI technique in detecting discontinuities in ferromagnetic materials.