How is PHYNIX Coating Thickness Gauge measured under harsh conditions?

special measuring tasks

How does the PHYNIX coating Thickness Gauge measure under harsh conditions? Not every measurement object is "desirable". You will often face practical difficulties that can lead to negative effects on measurement accuracy. Typical sources of error are curved, rough surfaces, edges or measurements on soft and sensitive coatings. Usual measurement calibrations result in accurate and reliable measurements. On the following pages you will find a list of suggested solutions for several typical sources of errors. "> When using a coating Thickness Gauge to measure coating thickness, not every measurement object is a satisfactory environment. You will often face practical difficulties that may lead to negative effects on measurement accuracy. Typical sources of error are Curved, rough surfaces, edges or measurements on soft and sensitive coatings. Usual measurement calibrations result in accurate and reliable measured values. On the following pages you will find a list of suggested solutions for several typical sources of error.

Surface measurement

Convex surfaces yield larger measurements and concave surfaces yield smaller measurements relative to planar measurements. This effect can easily be compensated with a calibrated measurement. However, the instrument does not require any additional calibration, measuring surfaces whose radii of curvature are greater than the reference value for the minimum convex radius of curvature (Rmin) listed in the table.

Smaller radii of curvature, uncoated objects should be tested with the same curvature whether the zero value or the measured value can be accurately measured with the calibration foil or whether adequate calibration needs to be performed on the curved surface due to excessive deviation.

Measurements on rough surfaces

Roughness is the enemy of coating thickness measurement! If no special measures are taken, coatings that are too thick on rough metal surfaces will be measured compared to measurements on coatings on smooth surfaces.

Using our Sufix® tool we suggest two methods that will allow you to broadly ease the effects of roughness. These methods can measure coating thicknessin the mountain.

Its coating thickness at peak is important when evaluating corrosion protection which is why the measured value at peak is self-evident. Coated surface roughness requires access to two methods in order to calibrate

Method 1 (applicable to roughness RZμ less than 20 m):

1. Zero Instrument: Position the probe approximately 10 times the rough surface for zeroing
2. A two-point calibration is performed: approximately 5 times the probe position, "foil calibration".
3. You can now measure: the number of times the probe was positioned. The average value corresponds to the average coating thickness of the peak

Method 2 (applicable to roughness RZμ greater than 20 m):

1. Calibrate the instrument on the same surface with a rough measurement object of the same shape and steel as the same type of coating (one-point or two-point calibration correction).
2. Position the probe about 10 times over the rough coating to measure the object and form the average x0+C {xzero+coating} from the measured value. this averagex0It is the effect on the roughness measured by the coating Thickness Gauge. You can also use the instrument's statistical averaging.
3. Measurement of coating thickness on rough surfaces. Position the probe approximately 5 to 10 times over the coating to take measurements. determine the mean x0+C {xzero+coating}From measurements described in 2. this averagex0+CInfluenced from coating thickness and roughness.
4. Calculate the difference in mean xx0+C -x0.. The difference is that the average coating thickness xCin the mountain

Measurement across sides

Near the edges of the coating thickness measurements there is a tendency to indicate larger measurements, i.e. the actual coating is smaller than the displayed value. This effect occurs when the distance from the edge of the measurement point is smaller than the probe diameter.

The different probe diameters are shown in the table below:

However, if the measurement is made appreciably close to the edge then a calibration of the probe diameter is performed on the uncoated part exactly at the specified distance from the edge. This will remove any edge error correction.

Measurements on soft and sensitive coatings

About 0.3n load pressure can leave soft and sensitive coatings for indentation. Coating thickness will appear too low.

TIP: Put a piece of hard plastic foil (30μm/1.2mils and 100μm/4mils, eg one of our measuring foils) on the probe between the measuring pole to reduce pressure and measure the total thickness of the coating. Subtract the foil thickness from the measurement.