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Online gauge improves product consistency
Online gauge improves product consistencyKeywords: Distance measurement, Thin film
Global medical company Smith & Nephew has cut costs dramatically by installing two NDC Infrared Engineering online gauges to provide closed-loop control of the film extrusion line at its extruded films factory near Hull, UK (see Plate 3). The 8000 series scanning weight gauge and automatic profile control system has improved set-up times by 50 per cent and halved coat-weight variation tolerance.
Located at Gilberdyke, near Hull (UK) Smith & Nephew manufactures a wide range of film and nets for the medical industry, such as breathable plasters, wound contact layers and bandages. Two of NDC Infrared Engineering's scanning gamma backscatter weight gauges are installed on the polyurethane film extrusion line. The gauges scan across the width of the web to provide coat-weight measurement to the automatic profile control system.
Polyurethane film is extruded onto a paper carrier, which is 1.5 metres wide. The first gauge measures the weight of the paper carrier. The second gauge is positioned further down the line to measure total weight of the extruded film and paper together. The first measurement subtracted from the second measurement provides total film weight. The gauge data is fed back to the automatic profile control system, which adjusts the extrusion die accordingly.
Plate 3 NDC Infrared Engineering's 8000 series scanning weight gauge installed on Smith & Nephew's film extrusion line at the Gilberdyke factory near Hull
Previously, coat-weight was measured by manually taking samples of film at the end of the process line. The new system allows continuous weight measurement rather than just at roll ends and is not destructive.
For more information contact NDC Infrared Engineering Ltd, Galliford Road, Maldon, Essex CM9 4XD, UK. Tel: +44 (0)1621 852244; Fax: +44 (0)1621 856180; Web site: www.ndcinfrared.com