Picture 2
specifically inspect and monitor single batches
or complete product lines depending on the field
of application of the polymers. In addition to the
application of online inspection and sorting systems
[1] during production, random samples are also
regularly inspected. SIKORA AG has developed a
special offline inspection system that reliably detects
and analyzes contamination from 50 µm in plastic
pellets.
Measuring principle of the X-ray based offline
inspection and analysis system
With the support of X-ray technology, a non-
destructive look into and through plastic pellets
is possible (picture 2). Furthermore, it can be
differentiated between miscellaneous materials, such
as pellets and metal particles, as they vary in their
absorption or attenuation of X-rays. Consequently,
even the smallest metal inclusions in the raw
material can be detected with the X-ray based
inspection and analysis system developed by SIKORA
AG. Since the X-ray unit is hermetically sealed, no
radiation can escape and the standards of the
Radiation Protection Act and Radiation Protection
Ordinance are fulfilled. Therefore, the system can
be used by the operator without any concern. The
system is characterized by its intuitive handling.
The operator places the material onto a sample tray,
where it is being moved through the inspection area,
which features an X-ray camera. The inspection
and analysis are carried out within 30 seconds. A
projector highlights contaminated material in
color directly on the sample tray (picture 3).
Simultaneously, the contamination is visualized and
highlighted on the monitor including information
about its size and area (picture 4). This allows for a
clear allocation of the contamination and facilitates
the removal, for example, for further inspections in
a laboratory. Due to the analysis of the X-ray images,
metallic contamination from a size of 50 µm on the
surface as well as within non-transparent, colored
and transparent plastic pellets are automatically
detected, visualized and evaluated. Contaminated
pellets can be selected on the monitor and zoomed in.
Picture 3: Sample tray with material samples:
Detected contamination are highlighted in color. On
the monitor, selected impurities are visualized on the
sample tray by cross hairs.
Data analysis and data recording
With the specially developed analysis software,
contaminants are detected, visualized and
evaluated on the monitor as well as on the
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WIRE NEWS December 2019 7