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convex surface conductivity value σ(φ)=56MS/m.
Hypothesis: curvature coefficient η(φ) =0.975 of convex pieces with curvature
diameter of φ=50mm( (η(φ) input see 5.3.2.7)
The actual conductivity
σ
act.=
σ(φ)
/
η(φ)
=56/0.975=57.4MS/m
Example 2: using diameter 14mm, conductivity values 60KHZ probe to measure the
concave surface of the work piece, the curvature diameter of work piece is 60mm,
measuring concave surface conductivity value
σ(φ)
=58MS/m
Hypothesis: curvature correction coefficient η(φ) =1.032 of work piece of
curvature diameter φ= 60mm (η(φ) input see 5.3.2.7)
The actual conductivity
σ
act.=
σ(φ)
/
η(φ)
=58/1.032=56.2MS/m
6.5 Edge Effect
The eddy current probes of the instrument are all used of electromagnetic shielding
technology, it has a significant difference from other not shielded probes(see Figure 6.2), diameter
of 14mm probe can measure the minimum area which has the diameter larger than or equal to that
of the probe, the diameter of 8mm probe can measure the minimum area which has the diameter
larger than or equal to that of the probe.
figure 6.2
And the measurement of the diameter of the non-shield probe is far greater than the diameter
of the probe, otherwise it will produce errors.
七、
POINTS FOR ATTENTION AND MAINTENANCE
7.1During calibration or measurement, need to keep the probe touching the sample