FREQUENTLY ASKED QUESTIONS
WHAT IS EVISIVE SCAN TECHNOLOGY?
Evisive scan technology is a nondestructive method for characterizing the internal structure of a bulk dielectric material through the use of microwave energy.
HOW DOES IT WORK?
The probe bathes the subject under inspection with microwave energy. Reflected energy is mixed with a portion of the out-going beam and the resulting field strength and phase are measured as the probe is moved across part surface. An image is created using the field strength and/or phase information which has been mapped to the probe’s location on the part.
IS MICROWAVE ENERGY SAFE?
The microwave sources used in Evisive equipment are below monitored exposure thresholds and require no special handling or precautions. Microwaves are non-ionizing, and cannot damage tissues in the way that X-rays can.
WHAT MATERIALS CAN BE TESTED?
Ceramics, fiber reinforced resin materials (FRP structures including pipe and tanks), polyethylene and other plastics, wood, Kevlar, pipe overwrap repairs, boat hulls, wind turbine blades, fiber bundle orientation in composites, both reinforced and non-reinforced rubber products.
WHAT FLAWS CAN BE DETECTED?
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Voids (air bubbles, poor mixing, incomplete contact, lack of glue)
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Inclusions (dust in PE pipe fusion butt welds, moisture, pre-impregnated panel backing material)
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Delaminations (rubber expansion joint, interlaminar disbonding in layered composites)
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Cracks
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Corrosion under coatings
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Thickness changes
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Any change in a material that changes the dielectric property of the material
WHAT ARE THE ADVANTAGES?
Evisive technology is a non-destructive, non-contact inspection method. No couplant or immersion is required. Inspection can be performed with access from single side only.
WHAT ARE THE LIMITATIONS?
Microwave signals cannot penetrate conductive materials, such as metal, and therefore cannot inspect material behind them. Other materials which reflect or absorb virtually all of the microwaves which impinge on them, such as water also make inspection of underlying structures impossible. However, this is often beneficial when inspecting dielectric materials backed by such reflective or absorptive material. For example, water-filled HDPE pipes (inspected from the OD) and metal-backed ceramic materials are easily examined by Evisive technology.