TQC Sheen LD5860, Operating Instructions Manual

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9.1 Notes for coating thickness measurement

To carry out the correct film thickness 
measurements not only a proper handling of 
the measuring instrument are an advantage, but 
also a basic knowledge of general handling of 
coating thickness gauges and the corresponding 
metrological requirements. 

This mainly concerns the following topics:
- Selecting the suitable measuring method
- Statistical evaluation methods of measurement  
   series
- Interpretation of measured values

We recommend in case of new (and random 
sample-based) combinations of materials, to check 
measured values of the PowderTAG against values 
obtained by other layer thickness measurement 
methods (such as a regular coating thickness 
gauge). If necessary the PowderTAG values can be 
corrected via a user calibration. (See section 10.3)

9.2 Preparation for measurement

Select the calibration that suits the measurement 
task. Depending on the application, you can 
select an existing factory calibration (powder, 
powder thick, cured). Measurements with 
maximum measuring accuracy can be achieved 
with calibrations that have been created from the 
combination of materials to be examined (see 
Chapter 10).

When a second layer of coating is applied the 
PowderTAG will add 25% of the layer thickness of 
the first (cured) layer to the measured value of the 
second layer. To calculate the actual layer thickness 
of the second layer this 25% has to be substracted 
from the measured value. 

E.G.: the first layer (cured) is 100 µm. The PowderTAG 
measures 85 µm on the second layer. Then the 
actual thickness of the second layer is 60 µm. (25% 
of 100 µm = 25 µm. 85µ - 25 µm = 60 µm)

9.3 Performing measurements
Freehand measurements

Photo-thermal measuring processes are non-
contact thus non-destructive.
While performing a freehand thickness 
measurement it is important to keep the correct 
working distance to the object. The LED-pointer 
helps to achieve this. The pointer consists of three 
on the sensor positioned LEDs. When the three LED 
pointers combine into one point on the object the 
correct distance is achieved and a measurement 
can be performed.

Measurements with distance cap

Generally, the use of a distance cap (Art. No LD5852, 
to be ordered separately) is recommended for 
touch-sensitive materials. This makes it possible to 
maintain an accurate working distance without the 
risk of touching an object.

Measurements with Tripod

For the contactless measurement of small parts and 
geometries, we recommend using a tripod.

10.1 General guide lines

Measure settings menu of the PowderTAG shows all 
the Calibration options. Three factory calibrations 
are available: Powder, Powder Thick and Cured.

It is possible to create user calibrations based on the 
factory calibrations. The PowderTAG has the option 
of single-point or two-point calibration.

To ensure an optimum calibration the following 
should be observed:
The quality of a calibration influences how precisely 
the layer thicknesses of a material system can 
be determined. A careful approach is therefore 
essential.

Please note that the powder coatings may vary 
greatly in nature and composition. Since the color 
in the photo-thermal layer thickness measurement 
also plays an important role, under cer-tain 
circumstances, despite calibration it occasionally 
may come to unsatisfactory measurement results in 
the color range of bright yellow, orange and red!

Calibration should be performed on a calibration 
object. The material properties of this calibrati-on 
object should match the material properties of the 
object to be measured as closely as possible. The 
better both objects match the better the calibration, 
thus the accuracy of measurement.

The results of a film thickness measurement 
only covers the measured positions of an object. 
It is therefore important to ensure that the 
measurement position matches the created 
calibration and the measurement position of the 
reference method. Moreover, it should in certain 
circumstances be ensured (by means of statistical 
methods), that the layer thickness information of 
the reference measurement and the calibration 
measurement are obtained from the same 
measurement area. This is particularly important 
with rough objects.

10.2 Factory calibrations

The PowderTAG has three factory calibrations 
(powder, powder thick and cured)

Powder:

Measures the expected dry film thickness after cure 
of powders with an expected dry film thickness 
under 50 - 150 µm.

Powder thick:

Measures the expected dry film thickness after cure 
of powders with an expected dry film thickness of 
50 - 250 µm and up.

Cured:

Measures the dry film thickness after cure of 50 -150 
µm.

The “Check Instrument” function in the “Instrument 
Settings” menu is no calibration tool. It only checks 
the UV-source (see section 8.5).

10.3 User calibration

The PowderTAG allows the use of up to 20 
calibrations. You can create a new calibration by 
selecting New Calibration (Measurement Settings> 
User Calibration> New Calibration). In the field type 
a factory calibration (powder, cured, powder thick) 
suitable for the material system to be examined 
can be selected. It contains basic information like 
measuring times and measuring method. After 
saving the new calibration, the menu for single-
point calibration or two-point calibration pops up. 
This allows for rapid calibration.

10.4 Calibration methods

10.4.1 Single point calibration - Powder

After confirming Powder and single-point 
calibration, you end up in the measured value recor-
ding of the calibration menu. Here you can make 
measurements, and adjust the measurement value 
manually.

9 MEASURING MODE

10 CALIBRATIONS