Goldanalytix BarScreenSensor Manual De Instrucciones página 27

The following procedure is recommended for precious metal bars:
Step 1: Density determination – Determine the density of the bar using a density scale (for
irregular shaped objects) or check the dimensions and weight of the bar using a digital caliper
and a precision balance. In this way, counterfeits made of materials with different densities can
already be detected in the first step, and in the following it can only be a counterfeit with
materials of the same density – these are for example metals like tungsten in the case of fine
gold or for silver, for example, lead-tin alloys or molybdenum.
Step 2: Conductivity measurement with the GoldScreenSensor – Verify the authenticity of the
precious metal ingot by determining the electrical conductivity using the GoldScreenSensor and
thus detect underalloys and counterfeits. Due to the limited penetration depth of the
GoldScreenSensor, it is essential to use another testing method for objects over 1 ounce in order
to detect any foreign metal inclusions that may lie deeper.
Step 3: Ultrasonic measurement with the BarScreenSensor – Perform ultrasonic measurements
with the BarScreenSensor to ensure complete penetration of the precious metal ingot and to
detect foreign metal inclusions.
Please also have a look at our website www.gold-analytix.com/knowledge for more
information about the correct procedure for the non-destructive testing of precious metals.
However, absolute certainty, especially regarding the exact composition of the test objects, can
only be provided by a destructive, chemical analysis.
Conditions for optimum measurement results:
 Surface condition: If possible, measure only on smooth, flat surfaces and not, for
example, on hallmarked areas. Rough or irregularly shaped surfaces can cause
measurement errors and result in inaccurate measurement values. Strongly defined
embossing, creasing or scratches can also lead to value deviations. Always apply a
sufficient amount of ultrasound gel onto the spot you want to measure.
 Parallel surfaces: Make sure that the opposing surfaces of the test objects are always
parallel. The measuring surface must be parallel to the opposite side, otherwise
inaccurate or false measurement values will result.
 Temperature: Ensure that the temperature of the environment and the test object is
constant. It is best to perform measurements only at room temperature.
 Calibration: Perform the calibration regularly with the included calibration piece of 4 mm
thickness to ensure reliable and precise measurement results.
 Thin test objects: For ultrasonic thickness gauges, it applies that if the test object is
thinner than the predefined minimum thickness of 20 mm, measurement errors may
result.
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