Non-contacting online layer-thickness measurement ... - Micro-Epsilon

A090_eCombination sensorcombiSENSORNon-contacting online layer-thickness measurement of foilsIn foil production online process monitoringguarantees constant product quality. MICRO-EPSILON’s KS5 combination sensor measures thelayer thickness on foils in a non-contact and thusnon-wearing process.Measuring processThe measurement of coatings on foils (e.g. adhesivelayer on self-adhesive foils) is based on thecapacitive principle. A non-contact capacitivedisplacement sensor is positioned at a fixed distancefrom a metal surface (e.g. transport roller). The foilpasses through the measuring gap and as adielectric changes the capacity of the sensor. Withconstant foil thickness the output signal onlydepends on the layer thickness.Compensation of measurement uncertaintyIn addition to the capacitive displacement sensor aneddy-current displacement sensor is also integratedin the sensor housing and arranged in the samemeasuring axis. Measuring coil and measuringelectrodes are of concentric design, which meansthey both measure against the same target surface.The eddy-current displacement sensor measuresthe distance from the transport roller and thuscompensates mechanical changes of the system(e.g. thermal expansion, or vibration).The signals ofboth measuring principles are combined arithmetically.This combination sensor principle guaranteesthat the measured thickness value is not influencedby possible distance changes.Cross-profiles by way of traversingIf a cross-profile is necessary during production, thisrequires a sturdy mechanical construction with atraversing facility. The sensor position is measuredwith a MICRO-EPSILON cable-pull sensor. Thecombination sensor guarantees that inaccuracies inthe mechanical construction (e.g. bending,eccentricity) are compensated in the measurement.This allows accuracies of 1 µm in the layer thickness.Traversing unit, sensor, measuring channels, andcomputer-based signal processing are all providedby MICRO-EPSILON.Reasons for choosing the system- Non-contacting, non-wearing measuring process- Exact, non-destructive test- Compensation of thermal expansion, eccentricityuncerainty- Cross profile by way of traversing- Adjustable tolerance limits- Scalable displayLayer thicknessFig. 2: Combination sensorCombinationsensor KS5Distance Sensor-rollerCarrier foilTransport rollerLayer

ApplicationLimit values and data archivingThe AZ801.02 function module with integrated zerosetting and adjustable limit switch makes it possibleto detect only changes of the layer thickness. Foilsections lying outside of pre-set tolerances can thusbe marked. At the output of the measuring system adata acquisition box is connected for data collectionand transfer to a PC.System configurationRS 584 - 8-channel table-top housing with powersupply unit, display, oscillator/ demodulator forcapaNCDT - PA 601 Pre-amplifier capaNCDTDT119.10-KS5A - eddyNCDT with oscillator/demodulatorCU 805 - Arithmetic combination of the twochannelsAZ 801.02 - Zero-setting and limit switchKS5 - Combination displacement sensor,measuring range 5 mmDD1605 - Digital display unitWDS-1000-P40 - Draw-wire displacement sensor,output 0-5VDCCU 805 AZ 801Technical details- Measuring range: 5 mm- Linearity: ± 0.02%- Thermal stability: ± 0.02%/KDT119.10KS5APA 60OS 602DL 600Foil + LayerRS 584TraversingunitWDS1000-P40DD1605Ambient conditions- Operating temperature: 50-95°C- Medium: air- Target: electrical conductor- Interference fields: acc. to IEC 1000-4-1- EMC: acc. to EN 50 081-2 and EN 50 082-2- Constant dielectric figures of carrier foil and layer.MICRO-EPSILONKoenigbacher Str. 1594496 Ortenburg / GermanyTel.: 0 85 42/1 68-0Fax: 0 85 42/1 68 90info@micro-epsilon.comwww.micro-epsilon.comTransport rollerA member of micro-epsilon group.Certified DIN EN ISO 9001 : 2000Modifications reserved Y9781090