BM1 Process

8/10/2019 BM1 Process

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Dept. Polymer Engineering

University of Minho

Extrusion BlowExtrusion Blow--Moulding:Moulding:

The ProcessThe Process


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University of Minho

ApplicationsApplications


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University of Minho

Extrusion based processExtrusion based process

Hopper

Controlpanel

Plasticising unit

Extrusiondie

Mould andclamping unit


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University of Minho



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University of Minho



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University of Minho



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University of Minho



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Dept. Polymer EngineeringUniversity of Minho



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Extrusion based process:Extrusion based process: extrusion headsextrusion heads


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Extrusion based process:Extrusion based process: die centringdie centring


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Extrusion based process:Extrusion based process: effect of sag andeffect of sag and extrudateextrudate swellswell

1 - swell and no sag

2 - sag and no swell3 sag plus swell


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Extrusion based process:Extrusion based process: axialaxial parisonparison thickness programmingthickness programming


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Extrusion based process:Extrusion based process: axialaxial parisonparison thickness programmingthickness programming


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Extrusion based process:Extrusion based process: effect of sag andeffect of sag and extrudateextrudate swellswell


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Extrusion based process:Extrusion based process: transversaltransversal paparisonrison thicknessthickness

programmingprogramming


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Extrusion based process:Extrusion based process: extrusion with accumulatorextrusion with accumulator

For containers of high capacity (>12.5 l)


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Extrusion based process:Extrusion based process: mouldsmoulds


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1

2

3

4Types of ventilation systems

Capacity (l) Slit depth (mm)>5 0.01-0.02

5-10 0.02-0.0310-30 0.03-0.04

30-100 0.04-0.10100-500 0.10-0.30


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Pinch-off


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Inflationwith needle


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Cooling system:

Channels diameter (d): 6 d 20 mm

Length: as short as possible (Texit-Tentrance 5C)

Reduced number of curve zones

Distance channel-cavity surface: d

Distance between consecutive channels: 1.5 d


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Extrusion based process:Extrusion based process: coco--extrusionextrusion

Permeability coefficients

Prices (relative to PVC)

HDPE

Adhesive

PA

Recycled HDPE


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Extrusion based process:Extrusion based process: coco--extrusionextrusion


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Injection moulding based processInjection moulding based process


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Advantages

Disadvantages


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Injection moulding based process:Injection moulding based process: designing predesigning pre--formsforms

Espessuras to pequenasquanto possvel

Razes de sopro elevadas

Machos cnicos (conicidademnima de 0.5)

Variaes de espessura por

maquinao da cavidade

Machos cilndricos

Variaes de espessura

por maquinao do macho


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Injection moulding based process:Injection moulding based process: sequence for designingsequence for designing

prepre--formsforms

1 Desenho do contentor (conhecido) e do macho (dimetro einclinao conhecidos)

2 Seleco das seces transversais a dimensionar

3 Determinao da espessura da pr-forma (balano mssico)nas seces seleccionadas no passo 2

4 Representao das espessuras determinadas no passo 3 nodesenho

5 Atenuao de transies bruscas de espessura

6 Clculo do volume da pr-forma

7 Repetio dos passos 5 e 6 at se obter um volume de pr-forma semelhante ao do contentor


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Stretch blow mouldingStretch blow moulding

Injection mouldingof the pre-form

Stretchingand blowing

Ejection of

the bottle


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Stretch blow moulding:Stretch blow moulding: sequence of stretch and blowingsequence of stretch and blowing

Wang et al., 1997

Blowing up without stretching


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Stretch blow moulding:Stretch blow moulding: sequence of stretch and blowingsequence of stretch and blowing

Wang et al., 1997

Blowing after stretching Blowing up while stretching


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University of Minho

Stretch blow moulding:Stretch blow moulding: material bimaterial bi--orientationorientation


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University of Minho

Stretch blow moulding:Stretch blow moulding: effect of orientationeffect of orientation


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University of Minho

Carbonated drinks:Carbonated drinks: permeability (COpermeability (CO22))

Maximise ratio volume / surface area

Geometry

Capacity


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University of Minho

Stretch blow moulding:Stretch blow moulding: typical processing parameterstypical processing parameters

(Blow-up ratio) x (stretching ratio)


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University of Minho

Stretch blow moulding:Stretch blow moulding: crystallisation kineticscrystallisation kinetics

Crystals cannot

form: moleculesare too sluggish

Crystals cannot

exist: moleculesare too energetic

Glassy

state

Rubbery

state

Melt

state

Temperature (C)

60 65250 255


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University of Minho

Stretch blow moulding:Stretch blow moulding: PET typical heat cyclePET typical heat cycle


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University of Minho

Stretch blow moulding:Stretch blow moulding: moulds for two stages processmoulds for two stages process


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University of Minho

Stretch blow moulding:Stretch blow moulding: two stages versus one stage processtwo stages versus one stage process

Advantages Disadvantages

Higher production rates

Better pre-form temperature control

Simpler bottle production (no need ofknow-how on polymer processing )

Higher global energyconsumption


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University of Minho

Extrusion BlowExtrusion Blow--Moulding:Moulding:

NonNon--Conventional TechniquesConventional Techniques


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University of Minho

NonNon--conventional techniques:conventional techniques: 3D technique3D technique


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University of Minho

NonNon--conventional techniques:conventional techniques: 3D technique3D technique

BattenfeldBattenfeldFischerFischer

Conventional 3D


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University of Minho

3D Technique:3D Technique: XX--Y mouldY mould

PlacoPlaco, Ltd, Ltd

Parison

Cavity

Blow mould


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3D T h i3D T h i


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University of Minho

3D Technique:3D Technique: mould with vacuummould with vacuum


PP bl i d ld ith bl tbl i g d ld ith bl t


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University of Minho

PrePre--blowing and moulds with moveable partsblowing and moulds with moveable parts

Doublewalled

container

PrePre blowing and moulds with moveable partsblowing and moulds with moveable parts


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University of Minho

Hollowcontainer withre-entrant zone

PrePre--blowing and moulds with moveable partsblowing and moulds with moveable parts

Sequential coSequential co extrusionextrusion


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University of Minho

Cycle time

Sequential coSequential co--extrusionextrusion

RigidRigid Flexible

Sequential coSequential co extrusionextrusion


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University of Minho

Sequential coSequential co--extrusionextrusion


Extruder 1 Extruder 2

Accumulator 1 Accumulator 2

Die flow channel 2Die flow channel 1

Single die lip

PressblowerPressblower processprocess


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University of Minho

PressblowerPressblower processprocess

BM1 Process

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