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Detecting cracks near fastener holes
Pencil probes are ideal for detecting small cracks in close proximity to fastener holes. Use a known crack or notch standard to set up the MIZ-21B or MIZ-21SR signal display. As you scan the test piece, you can estimate the depth and length of each surface crack by comparing the phase and amplitude of the generated eddy current signal to the standard's signal.
Multi-layer Corrosion Inspection
Identifying corrosion is one of the most critical and complex aspects of airframe inspections. Changes in skin thickness as well as varying multi-layer structures usually make it difficult to recognize signals. The MIZ-21B and MIZ-21SR have the power to penetrate thick sections. Exceptional signal-to-noise ratio helps inspectors distinguish even a small loss of material. Dual-frequency with mixing nearly eliminates the unwanted signals caused by varying air gaps between layers that can "mask" the signal of interest.
Digital Conductivity and Nonconductive Coating Thickness Measurement
Use digital conductivity measurements (resistivity) to characterize material or to inspect parts damaged by fire or lightning strikes. Directly measure the conductivity of metals and alloys, such as aluminum aircraft structures, using a dedicated conductivity probe. These probes have a broad operating frequency range, 50 kHz to 500 kHz, and are available with 1/4" or 3/8" diameter coils. Or measure a nonconductive coating such as paint. The instruments offer a wide measurement range for both conductivity and thickness.
Wheel Bead Seat Inspection
Early crack detection allows you to repair or replace damaged wheels before bigger problems develop. With Zetec's Bead Seat Probes, you can inspect this region with only one pass around the wheel, greatly increasing throughput. Each probe is molded to exactly fit a specific wheel, reducing the probe motion normally associated with free-hand pencil probe inspection. This stability results in better signal recognition and test consistency.
Airframe Fastener Row Inspection
Rapidly detect longitudinal fatigue cracks between fastener holes, such as at lap splices, with the MIZ-21B and the Reflection (Driver-Pickup) Sliding Probe. The inspection is performed with fasteners in place. The wide frequency range, 1-100 kHz, allows you to select low frequency for the multi-layer inspection, then switch to a higher frequency for top-layer crack detection. The shape and direction of the signal movement determines the location and approximate length of the flaw.
C-scan Display for Fastener Holes
The C-scan display is a unique way to present the "big picture" in fastener hole inspection. This method works exceptionally well when fasteners are removed. As the scanner rotates, successive sweep lines, 0-360 degrees, are drawn on the screen creating a pseudo 3D representation of flaws in the hole. Use the position of the flaw on the sweep line to plot its radial position. Each sweep line represents a known distance, so you can measure the location of the defect.
Probe Optimization
The MIZ-21B and MIZ-21SR also include a Probe Plot feature that plots probe response to both the test and reference specimens over a range of frequencies. This feature helps you choose the probe's optimum operating frequency for each application.
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