Fix Thickness Variations in Extruded Sheet

摘要

Non-uniform thickness in extruded sheet is a serious problem.In the case of thin sheet for thermoforming,uniform gauge is critical to achieving proper wall thickness in formed parts and to preventing optical distortion,both serious quality issues for packaging.With heavy sheet,gauge variation brings the added problem of warpage-you often have to reheat the sheet on rollers to get it flat.Gauge problems in the web can be in the machine direction(MD)or transverse direction(TD)and have a wide variety of causes related to equipment,material,and process.The traditional approach to reducing thickness variations is to add a scanning gauge control system.While beneficial,a better approach is first to address the issues causing the variations.