IPI Technical Presentation Compounding Basics - Requirements of - - PowerPoint PPT Presentation

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IPI Technical Presentation Compounding Basics - Requirements of Feeding, Dosing & Mixing

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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 Roller

Different extruder types are leading to different: types of potential material supply necessary dosing principles controls

parallel conical Ring Extruder

Definition of Extrusion

Extrusion a continuous, multi-stage manufacturing process for producing thermoplastic parts with a fixed cross-sectional profile

Definition of Compounding

Compounding a continous, multi-stage process for the production of plastic compounds formulations are done by mixing polymers and additives in a molten state using twin screw extruders

Products Masterbatch Compound

Typical Products in “Compounding”

Definition of “Compound”

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

Definition of “Masterbatch”

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

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Requirements of Dosing & Feeding

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

starve fed flood fed Dosing process Co-rotating Twin Screw Extruder (Co-TSE) Single Screw Extruder (SSE) Counter-rotating Twin Screw Extruder (Counter-TSE)

Definition of “Flood Fed”

Flood Fed (SSE, Counter-TSE)

• At all times of the process, the extruder is flooded with material

the extruder screw chamber is overfilled!!!

• Viewing the extruder main port from top, you cannot not see the

screw of the SSE and Counter-TSE

• Increasing the screw speed of the extruder always leads to

increased throughput rates Throughput rate is defined by the screw speed of the extruder and the throughput of the dosing unit has to follow

• The SSE and Counter-TSE are production lines for endproducts

(products are e.g. pipes, profiles, films and sheets)

• 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”

Starve Fed (Co-TSE)

• The dosing units are dosing max. the amount of material which is necessary

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

• Viewing the extruder main port from top, you can always

see the screw of the Co-TSE

• Increasing the screw speed of the extruder never leads to

increased throughput rates Throughput rate is defined only by the throughput rate

• f the dosing unit

Throughput and screw speed of the extruder are independently set from each other

• The Co-TSE is more a continous mixing device than a production line

for endproducts (products are pellets e.g. Masterbatches or Compounds)

• 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

synchronous dosing units synchronous dosing units (loss-in-weight) volumetric dosed gravimetric dosed

Dosing Principle, Devices & Process Integration

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

• f 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“

Srikanth, 20.04.13, mc India

Srikanth, 10.04.13, mc India

Feeding, Dosing & Mixing Technical Concepts

What are the goals of Dosing & Mixing?

• Defined material throughput per time unit with a dosing unit
• To guarantee quality constancy with controlled material throughput
• To guarantee a homogeneous mixture of all materials
• To guarantee process safety
• Cost optimization in regards of prime material consumption
• Process documentation (e.g. medical technology, automotive , etc.)

Materials Management – Dosing & Mixing

Process types:

• Continuous mass flow of material

(kg/h) Extrusion, Compounding

• Cyclical process interruption

(parts per hour)

• Discontinuous mass flow of material

with finite resolution Injection moulding

Discontinuous Continuous

Materials Management – Dosing & Mixing

Dosing unit types:

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

Continuous mass flow

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

Discontinuous mass flow

Synchronous Asynchronous

Cone dosing

Materials Management – Dosing & Mixing

Dosing methods: Volumetric dosing Dosing without weighing Gravimetric dosing Dosing with weighing

Materials Management – Dosing & Mixing

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 by

weighing detection in combination with closed loop control (Loss In Weight or Gain In Weight)

• High process safety
• Process logging & documentation

possible

• Expensive in purchasing

Synchronous Asynchronous Synchronous Asynchronous

Materials Management – Dosing & Mixing

Not suitable Technically possible Typical application

Dosing procedure Blow moulding Extrusion Blown film Fibre Flat- and strech film HT-sheet and HT-film Cable Sheet, Cast film Profil Pipe Asynchronous volumetric Synchronous volumetric Asynchronous gravimetric Synchronous gravimetric Dosing procedure Compounding In-Line processes Engineering- Compound Cable Comp. Masterbatch (Monobatch) Masterbatch (Tailor made) Metal- Comp.

• Natur. fibre

compound PLA- Comp. Conti. Disconti. Asynchronous volumetric Synchronous volumetric Asynchronous gravimetric Synchronous gravimetric

Materials Management – Dosing & Mixing

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Feeding, Dosing & Mixing Methods

Dosing methods: Volumetric dosing

Control

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

n 1. Manual measurement with measuring bin 2. Manual measurement with common lab scale 3. Manual adjustment

• f the control

Bulk density and throughput may change…

Materials Management – Dosing & Mixing

Gravimetric Dosing methods: Gain-In-Weight-Principle Measurement:

Quantity gain; Δ m/Δ t

Typical for:

Discontinuous processes, e.g. batching

+Δ

m

Materials Management – Dosing & Mixing

Gravimetric Dosing methods: Loss-In-Weight-Principle Measurement:

Quantity throughput; Δ m/Δ t

Typical for:

Continuous processes

• Δ

m

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

Materials Management – Dosing & Mixing

Gravimetric Dosing methods: 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 G SPECTROCOLOR G GRAVIPLUS

Materials Management – Dosing & Mixing

High resolution load cell

Gravimetric dosing phase Refilling phase Settle down phase

t m t t t m t m

i i i i

∆ ∆ = − −

− − 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

Materials Management – Dosing & Mixing

Dosing methods overview:

W S

Volumetric Gravimetric

S

Automatic Material conveying Material storage Automatic refilling Dosing bin with Agitator (if necessary) Load cell Dosing module with Controlled drive Filling level sensor technology Collecting bin and agitator (if necessary) Vibration damper

Materials Management – Dosing & Mixing

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Feeding, Dosing & Mixing Products

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°

Materials Management – Dosing & Mixing

Gravimetric dosing stations:

Dosing & mixing station for granules, powders, fibers & liquids Loss-In-Weight Dosing Unit GRAVIPLUS Screw dosing & mixing station for granules Loss-In-Weight Dosing Unit SPECTROCOLOR G Cone/Screw dosing & mixing station for granules Gain-In-Weight Blender GRAVICOLOR

Materials Management – Dosing & Mixing

Types of Dosing units:

• Single screw dosing units are used for

Free and normal flowing materials, easy bridging materials Pigments Regrinds

Materials Management – Dosing & Mixing

• Twin screw dosing units are used for

Non free flowing materials Shooting materials Sticky materials Difficult materials/powders as TiO2 ,,CaCo3, Talcum Reduction of pulsation effect Self-cleaning of screws

Materials Management – Dosing & Mixing

Types of Dosing units:

Dosing screw types:

Materials Management – Dosing & Mixing

• Vibratory dosing units are used for

Free flowing materials Glass fibers Natural fibers Carbon fibers Pulsation free feeding High feed ranges

Materials Management – Dosing & Mixing

Types of Dosing units:

Belt feeder dosing units are used for

Free flowing materials Chips Flakes Food High bulk density materials Recycling materials Damage less material feeding

Materials Management – Dosing & Mixing

Types of Dosing units:

Types of Liquid Dosing units / Pumps:

• Gear Pumps

Function For liquids with low and medium viscosities Example

Materials Management – Dosing & Mixing

Rotary Lobe Pumps

• Available for heated and non heated applications
• For liquids with low and high viscosities

Example

Materials Management – Dosing & Mixing

Types of Liquid Dosing units / Pumps:

Diaphragm Pumps

Function For liquids with medium and high viscosities Example

Suction Pump

Materials Management – Dosing & Mixing

Types of Liquid Dosing units / Pumps:

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

GRAVIPLUS

CFS65 CFS70 CFT22 CFT36

Application examples:

GRAVIPLUS

GRAVIPLUS 8- component station equipped with twin screw dosings as well as C-FLEX dosings. A typical masterbatch production based on pigments.

Application examples:

GRAVIPLUS

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

Application examples:

GRAVIPLUS

GRAVIPLUS 1-component station with CT36 for premix with agitator weigh hopper complete with refill system for compounding

Storage Control Drying Conveying Dosing & Mixing

Materials Management – Dosing & Mixing

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Questions ???? Feel free to contact: P Srikanth Motan-Colortronic India Ph: +91 44 2247 2423 Mob: +91 98400 23759 srikanth@motan-colortronic.co.in

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