9.-11. June 2014 - AIMCAL Web Coating & Handling Conference 2014 Europe

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Hydro Paper on Foil

Marcus Eue

Structure

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• Value Chain

• How to produce aluminium foil

• Material and production given aspects to be considered and controlled

01 Value Chain

Hydro Aluminium’s value chain

Bauxite/ alumina

Primary metal

Automotive

Casthouse products

Fabrication & Systems

Rolling Extru- sion

02 How to produce aluminium-foil

• first detection in LeBaux 1821.

• equator belt as main source.

• near to the earth-surface -> approx. 30m

• day mining.

Bauxite.. Bauxit

Aluminium..

• is the 3rd frequent element in the earth crust

• high internal reaction energy -> only as combined material in nature

• mostly combined with oxygene Al2O3 - Bauxite

Aluminium

8% misc.

17%

Silicon

28%

Oxygene

47%

Bauxite-mining production of Alumina primary aluminium (Aluminiumoxide)

+ -

Bauxit Alumina

Steps of aluminium production Produktionsschritte für Primäraluminium

4,5 t Bauxite => 2 to Alumina = > 1 to Aluminium Al2O3, Fe2O3, SiO2, TiO2, CaO Al2O3=Aluminiumoxid ca. USD 2000 / t 50% 10% 5% 2,5% 1%

Alumina

Melt (ca. 960°C)

liquid Aluminium

+

-

4 - 5 [V] 150 - 180 [KA]

From Alumina to Aluminium -> Electrolysis

Produktionsschritte zur Herstellung von Primäraluminium

Production Process – Casting (Direct Chill DC) & Hot Rolling

vs. ContinousCasting (CC)

Casting of slabs

Sawing and scalping

Production of aluminium-foil Slab dimension up to 9m x 2,20m x 0,60m

Slitting

Hot rolling

Cold rolling

Production of aluminium-foil

Cold Rolling

Doubling

Foil Rolling

Intermediate Annealing

Production of Aluminium Foil

Coil length after this steps (~0,006 mm gauge)

=> ~ 340.000 m

Separating and Slitting

Final Annealing

Shipping

Production of Aluminium Foil

Wide Foil Mill

Separating and Slitting

Annealing and Slitted Materials

Shipping

Annealing

03 Material and production given aspects to be considered and controlled

Thin foil for flexible packaging

10µm 600:1 600:1 10µm

human hair ~ 55 µm

Aluminium foil 6,3 µm

break-down tandem DC-cast pre-annealing hot rolling cold rolling annealing

process chain and typical microstructures in Aluminium sheet production

Core

Foilannealing - Finalannealing

Oxygen

Rolling oil

Goal: • unwinding properties to be secured • recristallisation – mechanical properties • degreasing • wettability as requested

Relative pressure

low

high

Distribution of winding-pressure inside a reel (schematic)

Core

9 µm (0.00035‘‘) foil behaviour at different tensions: 8 MPa 22 MPa

1 MPa = 145 PSI

Elastic deformation / Plastic deformation

Stress-Strain Curve (schematic)

0

20

40

60

80

100

0 0,5 1 1,5 2 2,5 3 3,5

Elongation [%]

Tens

ion

[MP

a]

0,2

30

Elastic;reversible Plastic; non-Reversible

1 MPa = 145 PSI

0102030405060708090

0 0,5 1 1,5 2 2,5 3 3,5

Tens

ion

[MP

a]

Elongation [%]

Stress-Strain Curve (schematic)

0,2

30

Example for specific web tension 6.3 µm (0.00025‘‘) or 9.0 µm (0.00035‘‘)

• 1,616 mm x 6.3 µm (63.6 ‘‘ x 0.00025 ‘‘)

• Tension 140 N

• Specific tension:

= 140 N / 1616mm x 6.3µm

(31.5 lbf / 63.6 in x 0.00025 in) = 140 N / 10,2 mm²

(31.5 lbf / 0.0159 in²) = 13,7 N / mm²

(1979 lbf/in²)

• 1,468 mm * 9.0 µm

• Tension 180 N

• Specific tension:

= 180 N / 1468 mm x 9µm = 180 N / 13,2 mm² = 13,6 N / mm²

1 MPa = 1 N/mm² = 145 PSI

Tension setting specific tension of 15 MPa [N/mm²]

Gauge

Width 6,3 µm (0,00025‘‘) 9,0 µm (0,00035‘‘)

800 mm (31.5 ‘‘) 7.6 daN 10.0 daN

1300 mm (51.2 ‘‘) 12,3 daN 17,6 daN

1400 mm (55.1‘‘) 13,2 daN 18,9 daN

1500 mm (59 ‘‘) 14,2 daN

20,3 daN

1600 mm (63 ‘‘) 15,1 daN 21,6 daN

1 MPa = 145 PSI

„Perfect“ unwinder (1)*

Peel Off Roller, Ø >200 mm

Dancer Roller

10 ... 20 mm

* Remark: based on TCS Foil experience, but consider Hydro is not machine producer

„Perfect“ unwinder (2)*

• centric fixing of the core

• soft chucks (expansion to center the reel)

• foil is supported by the moving peel-off-roller to keep the distance constant at all diameters

• rollers are driven

• roller diameter > 200mm (~ 8“)

• closed light/easy turning bearings

• Material: aluminium or CFK (carbon fibre) for thin foil (< 12-15µm)

PU 80-85 shore for thick foil (>15µm)

• notched rollers to minimize air flow (spirals or straight)

* Remark: based on TCS Foil experience, but consider Hydro is not machine producer

„Perfect“ unwinder (3)*

• all rollers parallel and dynamic balanced (Q=2.5)

• free foil length below 500 mm (~20 ‘‘)

• acceleration and breaking torques have to be considered (-> weight of rollers)

• Wrap-around angle -> influence on bending of rollers (e.g. 180° = 2 x tension); recommended is 90 – 120°

• pneumatic controlled dancer roller to keep web tension constant

• automatic tension control system

• web tension ~12-15 MPa (1,740 – 2,200 PSI) for thin foil

• In front of converting station there is a „S-part“ to stabilize the web (equal wrap-around and torques)

* Remark: based on TCS Foil experience, but consider Hydro is not machine producer

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Hydro Aluminium Rolled Products GmbH

BU P&B Foil Marcus Eue

Aluminiumstrasse 1 41515 Grevenbroich

Germany

Thank you for your attention