CSS 2

Technology

The Cleanliness Scanning System CSS 2 provides a continuous on-line supervision of the complete insulating material flow for impurities. For this purpose, the extrusion channel between the main extruder and the extruder crosshead is equipped with a sight glass and an optical CCD-camera system to transilluminate the insulation material for inspection.

The high resolution CCD-colour camera enables the system to detect impurities if the particle size is bigger than 20 µm and if these particles absorb light. The detection of the particle is done in two dimensions, whereas the vertical particle size can be measured precisely, while the horizontal size of the detected particle will be calculated from the flow speed of the insulating material in the measuring area.

Detected impurities are classified according to size. Particles exceeding the selected tolerance of the particle size and which are assumed to occur seldom are analyzed in detail by the CSS 2 computer system. The CSS 2 is able to provide information about the colour of transparent particle as long as the particle allows transillumination.

Combined with the graphical coloured display of the particle and its environment, the geometrical dimensions regarding area, vertical and horizontal dimension as well as the light absorption and colour are provided. The data of up to 100 of these impurities are registered on a hard disk (1.5 GB) for possible subsequent inspection.

Besides the graphical display of the detected particles and their environment, pictures representing part of the total material flow, shall be shown, even if the selected tolerance level is not exceeded. The content of these pictures will be analyzed and the results are sorted according to amount and size and shown in a histogram. This information serves to determine the start and end of production under aspect of the material cleanliness.

A printer provides an on-line report of detected contaminants, as well as a histogram with data about the number of detected particles sorted according to size. With an additional colour printer (option) the complete content of the monitor picture may be printed.

The CSS 2 measuring head is mounted on the sight glass assembly and can be lifted up manually by approximately 250 mm. Once the measuring head is lifted up it is easy to replace the sight glass, if necessary. There is no special calibration of the optic required after the measuring head is moved down.