IPI Technical Presentation Compounding Basics ...ipichennai.com/wp-content/uploads/Tech...

Srikanth, 10.04.13, mc India

IPI Technical PresentationCompounding Basics - Requirements of Feeding, Dosing & Mixing


Extrusion & Compounding

Principle of “Extrusion” & “Compounding”

Meat grinder principle

Different types of extruders

Extruder Single Screw

Twin Screw

Co-kneader

Internal mixer (e.g. banbury mixer)

Co-rotating

Counter-rotating

Planetary RollerDifferent extruder typesare leading to different:Ø types of potential material supplyØ necessary dosing principlesØ controls

parallel

conical

Ring Extruder

Definition of Extrusion

v ExtrusionØ a continuous, multi-stage manufacturing processØ for producing thermoplastic parts with a

fixed cross-sectional profile

Definition of Compounding

v CompoundingØ a continous, multi-stage process for the

production of plastic compoundsØ formulations are done by mixing polymers and

additives in a molten state using twin screwextruders

Products

Masterbatch

Compound

Typical Products in “Compounding”

Definition of “Compound”

v Compound

Ø Lower concentrated composite.Compound is used 100% in the end product !!!

Definition of “Masterbatch”

v Masterbatch

Ø Higher concentrated composite.Masterbatch is diluted in the endproductwith raw polymer (base resin) !!!


Requirements of Dosing & Feeding

Dosing processes in SSE / Counter-TSE and Co-TSE

starve fedflood fed

Dosing process

Co-rotating Twin ScrewExtruder (Co-TSE)

Single ScrewExtruder (SSE)

Counter-rotatingTwin Screw Extruder

(Counter-TSE)

Definition of “Flood Fed”

v Flood Fed (SSE, Counter-TSE)Ø At all times of the process, the extruder is flooded with material

à the extruder screw chamber is overfilled!!!Ø Viewing the extruder main port from top, you cannot not see the

screw of the SSE and Counter-TSEØ Increasing the screw speed of the extruder always leads to

increased throughput ratesà Throughput rate is defined by the screw speed of the extruder

and the throughput of the dosing unit has to followØ The SSE and Counter-TSE are production lines for endproducts

(products are e.g. pipes, profiles, films and sheets)Ø The SSE and Counter-TSE can build up pressure in the direction to the

downstream equipment (use of melt pumps not necessary)

Definition of “Starve Fed”

v Starve Fed (Co-TSE)Ø The dosing units are dosing max. the amount of material which is necessary

in the chamber of the twin screw to a max. 100%à no overfilling of the extruder screw chamber!!!

Ø Viewing the extruder main port from top, you can alwayssee the screw of the Co-TSE

Ø Increasing the screw speed of the extruder never leads toincreased throughput ratesà Throughput rate is defined only by the throughput rate

of the dosing unità Throughput and screw speed of the extruder are independently

set from each otherØ The Co-TSE is more a continous mixing device than a production line

for endproducts (products are pellets e.g. Masterbatches or Compounds)Ø The Co-TSE can not build up high pressure in direction to the

downstream equipment (often the use of melt pumps is necessary)

dosing principle

process integration

dosing device

Twin Screw Extruder

starve fed

synchronousdosing units

synchronousdosing units

(loss-in-weight)

volumetricdosed

gravimetricdosed

Dosing Principle, Devices & Process Integration


Feeding, Dosing & Mixing„consistent defined premix throughput per unit of time“

Feeding, Dosing & Mixing

In the game of Chess,

a „good formation“ is important to achieve a winning result,

since pieces in isolation cannot perform.Courtesy: „The Extruder Times – Steer Consultancy Services“



Feeding, Dosing & MixingTechnical Concepts

What are the goals of Dosing & Mixing?

Ø Defined material throughput per time unit with a dosing unit

Ø To guarantee quality constancy with controlled material throughput

Ø To guarantee a homogeneous mixture of all materials

Ø To guarantee process safety

Ø Cost optimization in regards of prime material consumption

Ø Process documentation (e.g. medical technology, automotive , etc.)

Materials Management – Dosing & Mixing

Process types:

-Continuous mass flow of material(kg/h)

à Extrusion, Compounding

-Cyclical process interruption(parts per hour)

-Discontinuous mass flow of materialwith finite resolutionà Injection moulding

DiscontinuousContinuous


Dosing unit types:

-No process interruption-Throughput indication in kg/h, etc.

à Continuous mass flow

-Batch dosing-Cyclical process interruption-Throughput indication in kg/batch/time

à Discontinuous mass flow

Synchronous Asynchronous

Cone dosing


Dosing methods:

Volumetric dosing

Dosing without weighing

Gravimetric dosing

Dosing with weighing


Dosing methods:

Volumetric dosing Gravimetric dosing

-Theoretical control of material throughput-Simple control mechanism-No complex measurement and control necessary

-No process controlling necessary-Economic in purchasing

-Control of material throughput byweighing detection in combination withclosed loop control (Loss In Weight or Gain In Weight)

-High process safety-Process logging & documentationpossible

-Expensive in purchasing

Synchronous AsynchronousSynchronous Asynchronous


Not suitable Technically possible Typical application

Dosingprocedure

Blow moulding

Extrusion

Blownfilm Fibre Flat- and

strech filmHT-sheet and

HT-film Cable Sheet,Cast film Profil Pipe

Asynchronousvolumetric

Synchronousvolumetric

Asynchronousgravimetric

Synchronousgravimetric

Dosingprocedure

Compounding In-Lineprocesses

Engineering-Compound

CableComp.

Masterbatch(Monobatch)

Masterbatch(Tailor made)

Metal-Comp.

Natur. fibrecompound

PLA-Comp. Conti. Disconti.

Asynchronousvolumetric

Synchronousvolumetric

Asynchronousgravimetric

Synchronousgravimetric



Feeding, Dosing & MixingMethods

Dosing methods:

Volumetric dosing

Control

Measuring:Quantity of dosed volume in relation to speed and time.Controlled by:Motor speed controller

n1.Manualmeasurement with measuring bin

2.Manualmeasurementwith commonlab scale

3.Manual adjustmentof the control

§ Bulk density and throughputmay change…


Gravimetric Dosing methods:

Gain-In-Weight-Principle

Measurement:Quantity gain; Δm/ΔtTypical for:Discontinuous processes, e.g. batching

+Δm



Loss-In-Weight-Principle

Measurement:Quantity throughput; Δm/ΔtTypical for:Continuous processes

-Δm

ð Independently from the weight measuring method a control and regulation loop is necessary !



Gravimetric dosing (LIW)

+

Load cell

Control

Loss In Weight processor

Measuring:Throughput measurement (mass flow)

Controlled by:Differential quotient of mass and time

n

§ Automatic calibration through Loss In Weight control and scale system

§ Compensation of bulk density changes

MINICOLOR GSPECTROCOLOR G

GRAVIPLUS


High resolution load cell

Gravimetric dosing phase

Refillingphase

Settle downphase

tm

tttmtm

ii

ii

∆∆

=−−

−

−

1

1 )()(

LIW process:Materials Management – Dosing & Mixing

LIW process:

Refill complete

Refill+settle down time must be less than 10% of total dosing time!

Refill window

Refill request


Dosing methods overview:

W

S

Volumetric Gravimetric

S

AutomaticMaterial conveying

Material storage

Automatic refilling

Dosing bin withAgitator (if necessary)

Load cell

Dosing module withControlled drive

Filling level sensor technology

Collecting binand agitator (if necessary)

Vibration damper



Feeding, Dosing & MixingProducts

Classifying the flowing characteristics (DIN ISO 3435):

• Classifying:

• Free flowing material: angle of repose α : 0 - 30 °

• Normal flowing material: angle of repose α : 30 - 45°

• Non free flowing material: angle of repose α : 45 - 60°

• Clumpy material: angle of repose α : > 60°

• Non-gliding material: sticking, bridge-building, difficult to separate

α

30°

45°


Gravimetric dosing stations:

Dosing & mixing station for granules, powders,

fibers & liquidsLoss-In-Weight Dosing Unit

GRAVIPLUS

Screwdosing & mixing station

for granulesLoss-In-Weight Dosing Unit

SPECTROCOLOR G

Cone/Screwdosing & mixing station

for granulesGain-In-Weight Blender

GRAVICOLOR


Types of Dosing units:

• Single screw dosing units are used forØ Free and normal flowing materials, easy bridging materialsØ PigmentsØ Regrinds


• Twin screw dosing units are used forØ Non free flowing materialsØ Shooting materialsØ Sticky materials Ø Difficult materials/powders as

TiO2 ,,CaCo3, TalcumØ Reduction of pulsation effectØ Self-cleaning of screws

Materials Management – Dosing & MixingTypes of Dosing units:

Dosing screw types:Materials Management – Dosing & Mixing

• Vibratory dosing units are used for

Ø Free flowing materialsØ Glass fibersØ Natural fibersØ Carbon fibersØ Pulsation free feedingØ High feed ranges


Belt feeder dosing units are used for

Ø Free flowing materialsØ ChipsØ FlakesØ FoodØ High bulk density materialsØ Recycling materialsØ Damage less material feeding


Types of Liquid Dosing units / Pumps:• Gear Pumps

Function

Ø For liquids withlow and medium viscosities

Example


Rotary Lobe PumpsØ Available for heated and non heated applicationsØ For liquids with low and high viscosities

Example

Materials Management – Dosing & MixingTypes of Liquid Dosing units / Pumps:

Diaphragm Pumps

Function

Ø For liquids with medium and high viscosities

Example

Suction Pump

Materials Management – Dosing & MixingTypes of Liquid Dosing units / Pumps:

C-FLEX ER (flexible wall feeders) with quick exchange modules:

GRAVIPLUS

CFS65CFS70

CFT22CFT36

Application examples:

GRAVIPLUS

GRAVIPLUS 8-component station equipped with twin screw dosings as well asC-FLEX dosings.

A typical masterbatch production based on pigments.


GRAVIPLUS

Compounding line for customized and flexible production of technical polymerPP, PS, PA with daily recipe changes.


GRAVIPLUS

GRAVIPLUS1-component station with CT36 for premix with agitator weigh hopper complete with refill system for compounding

Storage

ControlDrying

Conveying

Dosing & Mixing



Questions ????

Feel free to contact:

P SrikanthMotan-Colortronic India

Ph: +91 44 2247 2423Mob: +91 98400 23759

[email protected]

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mo‘s corner is the expert place where all questions relating to Polymer Material Handling will be answered!

If you have a problem [email protected]

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