Magneto-Optic Imager (MOI )

 

The Magneto-Optic Imager (MOI) uses an innovative eddy current induction method to induce magnetic fields in defects and magneto-optics to form images of the magnetic fields associated with the defects.  These field images closely resemble the defects themselves.

 

 

The MOI is available in the following configurations:

 

• The MOI 308/3 (303 imager) has a frequency range of 1.5 kHz to 100 kHz.
• The MOI 308/7 (307 imager) has a total frequency range of 1.5 kHz to 200 kHz.  This smaller imager has two different excitation attachments.  The low frequency unit has a frequency range of 1.5 kHz to 50 kHz and the high frequency unit has a frequency range of 20 kHz to 200 kHz.  They are interchangeable and snap on to the imager.
• The MOI 308/37 includes both the 303 and 307 imagers.
• The MOI 308 TDF (Turbo Dual Frequency) comes with the 303 imager and has dual frequency excitation contained in the imager.  This provides higher power with more sensitivity, resulting in better resolution.

The primary difference between the MOI 308/3 and the MOI 308/7 is in the size and weight of the imagers and the image field of view (FOV).  Due to its larger FOV (5.6cm x 4.4cm) the MOI 308/3 may allow for easier interpretation of subsurface corrosion as well as larger coverage area.  The higher frequency range of the MOI 308/7 (FOV of 3.5cm x 3cm) allows a wider range of application to include lower conductivity materials such as titanium and stainless steel with improved resolution.  Its light weight and small size permit its use in restricted areas as well as making it ideal for general surface and subsurface inspections.  The MOI 308 TDF has the same capability as the MOI 308/3, but now includes Alodine rivet inspection ability.

 

The MOI is a major improvement in terms of reliability as well as speed for many inspections involving both high and low frequency eddy current applications.  It has demonstrated its superiority in inspections for surface fatigue cracks, particularly on large areas such as fuselage skins and wing panels.  Use of the MOI for the detection of subsurface cracks and corrosion shows its versatility.  Reliability, ease of use, no calibration needed and minimal training requirements make the MOI a most cost-effective instrument for many inspection applications.