Pixargus developed the WebControl-Tex inspection system specifically for challenging surfaces of opaque or translucent materials. When analyzing the surface, a dedicated algorithm suppresses the natural surface structure. This makes it possible to detect defects apparently concealed by the normal structure of the material.
The system detects and classifies irregularities in leather structures, weaving defects in glass mats, dense spots in non-woven fabrics and even faintest scratches or so-called orange peel defects on dark, opaque foils. As soon as the system detects a defect, it triggers an alarm. As an optional feature, it may also mark the affected area.
An algorithm specifically developed for the detection of long defects, such as scratches, is capable of indicating the existence of defective rollers in the production line.
Björn Lindner, Managing Director of Pixargus, sees important benefits for manufacturers of web material. ”The manufacturers of surface inspection systems used to concentrate on materials with a uniform surface structure, as found on metals, foils and paper. We have developed new algorithms which enable us to reliably detect surface defects also against highly irregular backgrounds. We know how to find the needle in the haystack.”
Pixargus’ customers may use the data provided by the system beyond quality assurance in the final inspection procedure. The data also helps manufacturers to optimize their production processes and avoid the occurrence of defects in the first place. For example, trends in the frequency of surface defects are captured in real time, so that remedial action can be taken immediately. The operators can directly intervene, take corrective action and sort out the defective material.
The system works dynamically. It automatically adapts to the surface structure and colour of the material. Therefore it is generally not necessary to run a time-consuming teach-in procedure to preset the system to the specific surface structure, as required by conventional inspection systems. All that needs to be done is to input the relative amplitude of the textured structure and the size of the smallest to-be-detected defect.
A classification and defect density management tool enables the definition of detection and classification rules. Thus the operator can individually determine which and how many defects are tolerable within a specified area.
WebControl-Tex is a modular system, available for material widths between 150 and 8,000 mm. Depending on the surface characteristics, Pixargus supplies the system with a camera having a resolution between 40 and 150 µm. Opaque product can be inspected on one or both sides. The system operates at product speeds up to 600 m/min depending on the textured structure.
The material surfaces are illuminated by long-life LEDs.
The system and all its functions are operated via touch screen. A graphical display shows the material surface and individual defect images. All components are encapsulated according to IP 64. Remote access via Ethernet and IP-based communication enable quick system diagnosis.