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| | | | | | | | | | | | | | | | | | | | | | | | | | | FILMCQNTROL. Series 8101 | | | | | | | | | | Non-contact thickness measurement of blown film | | | | | | | | | | FILMCONTROL 8101 acquires the thickness profile of blown film in a non-contacting manner. The system operates based on the capacitive measurement principle and is used in industrial production directly after the extrusion die. The capacitive transducer measures the blown film without making contact. To obtain precise measurement results, the distance between the sensor and the film is kept almost constant. Therefore, pneumatics, which creates an air cushion in the immediate vicinity, flows from the face of the sensor. This cushion is maintained stable with the aid of a pneumatic closed loop control. The sensor unit is similarly supported on air and is also equipped with a ball coupler to compensate deviations of the bubble from the ideal geometry. The unit, consisting of the sensor and measurement processor, is mounted on a reversing frame and determines the thickness profile round the extruded blown film. The measurement results are transferred directly to a host computer which controls the die gap with the aid of these values. Additional sensors inspect the condition of the bubble and the position of the capacitive profile sensor to ensure high process reliability. | | | | | | Universal joint | | | | | | | | | | | | | | | | | | | | Tilt sensor | | | | | | | | | | Film thickness i—i | | | | | | | | | | | | | | The capacitive thickness measurement principle: The thickness of insulating material can be measured with the capacitive measurement principle. The electric field is propagated through the target and terminates on the ground industrial electrode. With a constant relative dielectric constant and a constant distance of the electrode to the target material, only the changes in the material thickness influence the measurement. | | | | | | | | | | | | | | | | | | | | | | | | | | |
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