Developments in on-line Gauging of Complex Extrusion Coating An - - PowerPoint PPT Presentation

Developments in on-line Gauging of Complex Extrusion Coating – An update Stefan Schöneberger Session 10.4 /7629

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Presentation Overview

• Introduction
• Complex extrusion coating process
• Optimum sensor requirements
• Overview of available sensor technologies
• Comparison of various sensor technologies
• Best choice of optimum sensor technology: HR-FSIR
• Process Control; Process Tools; Process Visualization
• Conclusion: Techno-Economic Benefits

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Introduction

• Rapid growth globally in complex web coating lines
• Aseptic packaging of liquid consumables

– Multilayer product for barrier properties & long shelf-life – attractive packaging for consumer attention

• Highly competitive Marketplace with rising raw material

costs & tightening margins

• Large capital investments in high-speed complex

extrusion coating laminators

• Increasing requirements for on-line gauging

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Complex Extrusion Coating Process

• Product structure

– Printed paperboard substrate or metallized film laminated substrate – Mono layer extrusion (outside layer, tie layer) – Multilayer co-extruded barrier coatings – Lamination: Aluminum Foil or Blown Film

• Process

– Extrusion Coater/Laminator – Multi coating stations (outside layer, tie-layer, inside layers) – High speed production process

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Optimum Sensor Requirements

Ability to:

• Measure true absolute thickness/basis weight of

coatings of varying densities on different substrates.

• Provide non-contacting measurement with low noise

and fast response.

• Provide high performance dynamic measurement of

coatings independent of substrate variations in a high- speed production environment.

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Overview of on-line sensor technologies

Major categories of on-line sensor technologies for complex Extrusion Coating Process are:

• Nuclear Sensors
• X-Ray Sensors
• Full Spectrum InfraRed Sensor (High Resolution FSIR)

based on Absorbance Mode (SpectraBeam)

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Nuclear Sensors

• Based on Beta or Gamma Radiation; Subject to source

decay: (PM-147;KR-85;SR-90:AM-241)

• Radioactive; hence requires licensing for use and

disposal

• Measure Basis weight (Not thickness)
• Cannot discriminate between layers in multilayer

coatings

• Use subtractive measurements for coat weight
• Use synchronized same-spot
• Use substrate-independent calibration technique (True

Net Coat Algorithm)

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X-Ray Sensors

• No licensing required.
• Not subject to regulations for use at strengths below 30

keV

• Measure Basis weight (Not thickness)
• Cannot discriminate between layers in multilayer

coatings

• Composition sensitive
• Use subtractive measurements for coat weight
• Use synchronized same-spot
• Use substrate-independent calibration technique (True

Net Coat Algorithm)

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X-Ray & Nuclear Sensor Measurement

• Both X-Ray and Beta Ray Gauges Are Total Mass Gauges
• Particles will be absorbed by all mass between source and

receiver

• Must pay attention to dimensional (z) and air mass changes

Nuclear Gauge

Output Signal Web Pm-147 or Kr-85 Source Capsule Ionization Chamber

All Mass is Measured

Web

X-Ray Gauge

Output Signal Isotope Or X-Ray Tube Ionization Chamber

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High Resolution FSIR Sensors

• Non-radioactive
• IR measurement based on absorbance
• Full spectrum analysis using Chemo-metrics effectively

eliminates or minimizes sensitivity to additives, printing etc.

• Insensitive to web or air temperature
• Is an on-line spectrometer
• Elliptical geometry of 6 x 25 mm design allows

measurements closer to web edge, resulting in enhanced streak-detection capability and better edge control and potential less edge trims.

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Physics Behind IR Measurement - General

Each Material Has Unique Absorption Pattern Stronger Weaker Absorption is Stronger At Certain Wavelengths Compared to Others

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SpectraBeam FSIR Sensor

Optics Optics Web MSP Tuning Fork Lamp Filter Matrix Fixed Detector Array

Full Absorption Spectrum

Only Mass or Thickness of Polymer is Measured

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SpectraBeam Sensor

S i g n a l A b s

• r

p t i

• n

I n t e n s i t y

Lamp Response Material "Signature" Full Spectrum Array

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Chemo-metric Analysis

Full Spectrum Array Accurate Calibration for Coatings on various substrates (Pigmented or Printed) Chemo-metric Analysis & Pattern Recognition Software

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Chemo-metric Analysis

Measured Standardized Spectrum Composition #1 Composition #2 Effect #1 (TiO2) Effect #2 (surface) Residual

A b s

• r

p t i

• n

Eliminates errors caused by Surface Finish, Colorants and other Additives

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Measurement Technology Comparison

Criteria SpectrabeamFSIR X-Ray Beta Noise Characteristics Good Good Nuclear Statistics Noise degradation over time None None source decay

Tolerance to Web Flutter

Best (+/- 5 mm) Good(+/- 3 mm) Fair (+/- 1 mm) Temperature Sensitivity No Yes Yes X,Y,Z Sensitivity No Yes Yes Composition Sensitivity No Yes Some Dynamic Repeatability Best Good Good Multilayer Coating Calibration Complexity Moderate High High Polymer Discrimination Possible No No Multi-Component Measurement Yes No No Exact same- spot Yes No No Substrate effect Minimum Yes Some Printing, Additive Effects Minimum Yes Yes

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Best Choice of Optimum Sensor Technology

Based on the comparative studies of various available technologies as discussed in this presentation: High-Resolution Full Spectrum InfraRed Sensor (on-line Spectrometer) offers the best choice for the accurate dynamic measurement of multilayer coatings in complex Extrusion Coating Applications. Reflectance HR-FSIR configuration is ideal for measurements of outside layer on paper/board or metallized film laminated substrate and co-extruded inside layers on foil.

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Process Control

• Auto Profile Control (APC) with Accelerated Thermal

Response (ATR) feature helps reduce CD Variations

• MD Control helps reduce Long Term Machine Direction

variations

• Yield Optimization Control: Target Management Control

(TMC) Helps in Polymer Material Savings

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Process Analytical Tool

• Fast Fourier Transform (FFT)

Helps in reducing short term machine direction variations caused by extrusion/laminator equipment

• Edge Zoom based on extended data

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Process Visualization

• Contourview Display Suite
• Contour View Display (3 Dimensional)
• Blanket View Display (Topographical)

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Techno-Economic Benefits

• Customer Results - Multiple case studies in Complex

Extrusion Coating Applications:

• Reduction in CD variations: 50 to 90%, typically 70% in

20 minutes from startup

• Faster product change-over, typical reduction by 67%
• Scrap reduction (start-ups,edge & sampling scraps): 50%
• Increased edge measurement and control: Additional 2%
• f width

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Conclusion

• Computer-based on-line gauging systems

with optimal sensor technologies, advanced process control & process analytical tools is a powerful Process Management Tool for complex Extrusion/Laminating Processors.

Thank you for your attention. Questions?