corporate training and planning extrusion. corporate training and planning film blowing, mono- and...

CORPORATE TRAINING AND PLANNING

EXTRUSION


Film Blowing, Mono- and Multi-layer and Double Bubble Film Blowing

3-layer 3 extruders3-layer 2 extruders 5-layer 3 extruders

5-layer 4 extruders 7-layer 4 extruders 7-layer 5 extruders

AXON manufacture machinery for both processes

There are two techniques of

making film. One is the cast film

process. The other is the blown film

process. The difference in qualities is

that the blown film is more christalline

than the cast film

FILM BLOWING

http://www.axonmachinery.se/ccol6.htm#3-2ext







Blown Film Co-Extrusion Barrier properties is the main reason to go for multi layer film

Three layer Co-Extrusion Five layer Co-Extrusion


MULTILAYER BLOWN FILM

Please check below a number of layer-designs from 2 layer up to 7 layers. The glue-layers are of great importance where two different polymers are not compatible

3-Layer head for 2 extruders -Layer head for 3 Extruders


Multilayer Film DiesMultilayer Film Dies

Two types of dies: 1.Feed Block 2.Multimanifold In Feed Block the melt streams are brought together and flow

out the die In Multimanifold the melt spreads independently and meet at

the die exit Two types of process Oscillating Platform Oscillating Haul-Off


MULTI LAYER FLAT FILM DIES

Feed Block

Multimanifold three-layer flat-film die


Advantages of Multi-layer FilmAdvantages of Multi-layer Film

Two to seven layers depending on the application. It possesses good barrier properties against gas and

moisture. High tensile,impact and tear strength. Good stiffness,optical,carrier and printing properties. e.g. LDPE/HDPE/LDPE,LLDPE/LDPE..etc.


Sheet Extrusion

Sheet is produced by forcing molten thermoplastic through a long horizontal

slit die. The extruded hot web passes around metal cooling rolls and is then

cut up or rolled up.

Material used :

HIPS is the most important sheet material. HDPE, PVC, ABS are also used.

Sheet grades usually have high melt viscosity.


Process Line

The sheet leaving from the slit die is picked up by vertical stack of three rolls.

The polishing rolls are usually chrome-plated and provided with temperature control by circulating oil. The polishing rolls imparts a good surface to the product without warpage. The temperature of the top rolls should be as high as possible without sticking, while the bottom roll should be just cool enough to prevent distortion.

From the polishing rolls the sheet passes along a conveyor, which consist of free running rollers.

The sheet is pulled by the pulling rolls are covered with elastomer. Their speed is adjusted to be slightly less than that of the polishing rolls to allow for shrinkage that takes place as the sheet cools.

The sheet is cut into desired dimensions by means of razor blades (thin sheets), shear cutting device (Standard sheets), or circular saws (thick sheets).


Sheet Extrusion Line


SHEET EXTRUSION ON 3-ROLLER CALANDERS


Various Cross-Sections of Flat Sheeting Dies: Circular, Tear drop, Angular and Flat Teardrop

DiesDies used in sheet extrusion are similar to that of flat film dies. Various cross-section of a flat sheeting die is shown in fig


Extrusion coating The plastic is coated over a substrate like paper, by extruding through a slot

die downward between two rolls.

Substrate is fed between the molten plastic and the roll and is joined with the plastic by pressure between rolls without the use of an adhesive.

Material used LDPE & PVC

PP, HDPE, Ionomer etc. are also used.

Equipment compresses of

Pre treatment unit

Coating unit

Take off & winding

Sketch of Paper Coating for Extrusion Process


Dies

Coat hanger die

‘T’ type die

Coat-Hanger Die : (a) Die Body, (b) Manifold, (c) Fixed Jaw, (d) Movable Jaw, (e) Choker Bar, (f) Clamping Screw and (g)

Jaw Adjusting Screw

Manifold T-die : (a) Die Body, (b) Manifold, (c) Adjustable Lip and (d) Clamping Screw


Wire Coating/Cable CoveringUnit comprises of

Un wind unit (For conductor)

Pre treatment unit

Wire coating unit

Steps Involved

Wire/conductor is unwound & straightened by Tension

Control Unit.

Pre treated to promote adhesion of molten plastic

Then passed through the Cross head die of the coating unit

Coated wire is then cooled by passing through cooling trough

Wound on the winder

Cooling Trough Take off/ wind up.


Wire Coating Extrusion Line

Diagram of a production line for the coating of wire or cable with plastic. The conductor to be covered unwinds at the left, is preheated, passes into the crosshead die (center). The extruder is behind the die, and feeds it with molten plastic, which coats the conductor. The finished product is cooled, tested and wound up at the right.


Die used

Tubing die

USED MAINLY FOR SECONDARY INSULATION

USED MAINLY FOR PRIMARY INSULATION

Pressure die


Dies

T-TYPE

DIE

COAT HANGER

TYPE DIE ( Widely Used)

Coat Hanger type of Die is much more stream lined than T-type Die


Tube/Pipe Extrusion

Wall thickness & flexibility/Rigidity differentiates between tube/pipe

Pipes are produced by horizontally extruding molten polymer through an annuler opening into several sizing, cooling devices that stabilizes the final dimension.

Comprises of

Extruder

Die

Sizing device

Cooling bath

Cater puller

Cutter or winder


DIES USED

STRAIGHT THROUGH

OFF SET DIE


Sizing Equipment - MethodsVacuum Trough

Widely used

With the help of vacuum, Pipe is stabilized and sized to retain the shape

Sizing Sleeve

Methods fixes the outside pipe diameter as it hardens by contact with a water cooled metal sleeve.

FLOATING PLUG SYSTEMS- USED FOR RIGID PIPES OF MEDIUM AND LARGE SIZES

TO PREVENT LOSS OF AIR PRESSURE FLOATING PLUG SYSTEM IS USED


Extended Mandrel

Method uses a water cooled extended mandrel

Provides additional internal cooling and internal support

Sizing plate

Method involves pulling the pipe through a series of brass plates

Mainly for small dia pipes/tubes.


Extrusion of Mono filaments

Mono filaments are wise like polymer strands of dia 0.09 to 1.52 mm. Usually they have circular cross-section.

The polymer melt from extruder is pumped out through a multi-hole die, quenched, stretched/oriented and annealed to get the filament of enhanced properties.

The production process comprises of Extrusion Filament forming Stretching (orientation) Annealing Winding


A

B

C

D Liquid-bath method

Orientation Systems

Air - Oven method

Heated Point method

Cold Drawing


Extrusion -- Box- Strappings

The process sketch is similar to Monofilament line except the die – A slotted die is used in place of multi-hole monofilament die

Plastic Strappings, made of PP/HDPE replace iron because of their flexibility.

Process outline

Plasticated melt from an extruder is pumped out through a slot die

Quenched in water bath

Bath temperature - 800C for PP

- 900C for PA-6

Passed through a orientation system and stretched to about 8 times in order to improve tensile properties.

Annealed in an annealing chamber to relieve the stresses

Wound on winder.


CORRUGATED PIPES The characteristics of corrugated plastic pipes depend on profile and

material.

Corrugated pipes have either parallel ring grooves or a continuous helical groove.

The pipes design can be single walled or twin walled.

Most common thermoplastics are PVC, PE,PP, PA and fluoropolymers.

The most important advantages are

Considerable raw material savings

High pressure resistance with good flexibility.

High impact strength

Good hydraulic characteristics


Essentially IIIr to extrusion of pipes except that the die and the calibration units are specially designed to produce corrugation on the pipes.

The cylindrical part of the pipe die head extends into the closed area of a revolving mould block chain. The plastic tube is pressed against the profiled, revolving mould block halves by internal air pressure or by vacuum calibration.

As it passes through the forming machine, it is cooled by contact with the mould blocks, and by that time it reaches the end of the chain, the tube must be sufficiently cooled to leave the rotating mould blocks in a stable form.

Process


a--Pipe die head with Insert

b--Compressed air inlet

c-- Shaping die

d -- Sealing stopper

e -- Vacuum connection


In order to let the pressure or vacuum sizing become effective,

the molten tube must be brought over a special extended outer die ring

as close as possible to the moulding chain –inlet. Otherwise the tube

would be blown off in pressure sizing and fail in vacuum sizing.The

extended position of the outer die ring cannot be heated separately. So

that it must be made of a material of high thermal conductivity.


Double walled corrugated pipe production:

The manufacturing process is the same as with

standard corrugated pipes, but when the first tube has been

formed, the second tube is laid smoothly on the inner

surface of the still plastic corrugation and welded to the first

with the aid of a sizing mandrel.


Double Walled Corrugated Pipe Productiona -- Die for coextrusionb --Through flow guidec --Mandrel extrusion for inner layerd -- Shaping die


Applications of Corrugated pipes are:

Conduits for cable protection, TV,Telephone, Glass fibre, power, control and computer lines, automobiles, machines and planes, protective pipes and conveyor pipes.

Drain pipes for fields, streets, squares and houses.

Pipes for vacuum cleaners, washing machines, dish washers, medical application – drip irrigation, hoses for fields, hot houses and plantations.

Protection pipes for district heating, domestic connection lines, structural and civil engineering.

Large size pipes for sewage, waste water, control shafts and conveyor pipes.

Corrugated pipes are produced with diameters form 3\5 to 2000mm.


POST EXTRUSION FORMING

Inline postforming with extruder : Embossing one or both sides with shallow or deep patterns


INLINE FIXED / ROTATING RINGS USED TO TWIST EXTRUDATE


INLINE VACUUM/PRESSURE FORMER FOR PLASTIC SHEEET WITH MATCHED, WATER COOLED

FORMING MOULDS ON CONTINOUS CONVEYOR SYSTEM

AN INLINE COIL FORMER CAN PRODUCE TELEPHONE CORDS, SPRINGS, ETC., USING EXTRUDED ROUND, SQUARE, HEXAGONAL, AND OTHER SHAPES


PROBLEM CAUSES (S) SOLUTION(S)

General Considerations

Surging

Resin bridging in hopper Eliminate bridging

Incorrect melt temperature Correct melt temperature

Improper screw design Check design

Rear barrel temperature too low or too high

Increase or decrease rear temperature

Low back pressure Increase screen pack

Improper metering length Use proper screw design

Gels(Contaminants that look like small specks or bubbles)

Melt temperature too high Lower melt temperature

Not enough progression in screw use new screw

Bad resin Check resin quality

Melt fracture (Rough surface finish)

Melt temperature too low Increase melt temperature

Die gaps too narrow Heat die lips

Increase die gaps

Use processing aids

TROUBLE SHOOTING


Bad colour

Colour concentrate incompatible with resinEnsure melt index of concentrate base

Bubbles

Wet material Dry thoroughly

OverheatingDecrease temperature; check thermocouples

Shallow metering sectionUse proper compression-ratio

screw

Overheating

Improper screw design Use lower-compression screw

Restriction to flow Check die for restrictions

Barrel temperature too low Increase temperature

Die lines

Scratched die Refinish die surface

Contamination Clean head and die

Cold polymer Check for dead spots in head;

adjust barrel and head temperature to prevent freezing

Flow lines

Overheated material Decrease temperature

Poor mixing Use correct screw design

Contamination Clean system

Improper temperature profile Adjust profile


Blown FilmWrinkles Dirty collapsing frame Clean frame

Too much web tension Adjust tension

Improperly designed air ring Use new air ring

Gauge variations See gauge variations

Insufficient cooling Use refrigerated air

Increase flow of Air

Reduces output

Misalignment between nip rolls and die Check alignment

Fold, creases Excessive stretching between nip and roller Reduce winding speed

Nip assembly drive not constant Adjust or replace drive

Blocking Inadequate cooling Use better cooling method

Excessive winding tension Adjust tension

Excessive pressure on nip rolls Adjust pressure

Bad resin Check resin

Port lines Melt temperature too low Increase melt temperature

Die too cold or too hot in relation to melt temperature Adjust die temperature

Splitting Excessive orientation in machine direction Increase Blow-up ratio

Degraded resin Reduce melt temperature

Poor resin choice Ensure resin is suitable


Die lines Nick on die lip Chande die

Dirty die Clean die

Inadequate purgingIncrese purging time between resin changes

Gauge variations (machine direction)

Surging

Check temperature

Check hopper for bridging

Inconsistent take-up speed Check take-up speeds

Gauge variations(transverse direction)

Non-uniform die gap

Adjust gap

Centre air ring on gap

Printing problems Insufficient treatment Use properly treated film

Additives interfering with inkUse resins with no interfering additives

Erratic treatmentReduce slip levels to about 600 ppm for water-based inks


Sheet

Poor gauge uniformity Melt flow is not stable Use gear pump to stabilise flow

Viscosity not stable Poor mixing Use static mixer

Streaks Contaminated System

Clean hopper

Check screw and die;

Clean if necessary

Total discoloration Excessive regrind Check amount of regrind used

Discontinuous lines Too much moisture Increase resin drying

Use hot regrind


Pipe and Tubing

Poor output Improper die or screw designEnsure die and screw are designed for desired output

ID blisters

Insufficient vacuum Increase vacuum

Excessive moistureMaintain normal percentage of moisture in compound.

Gases entrapped Reduce temperature

Water inside pipe Stop water access

ID burn streaksMandrel heat too high Check mandrel heat

Stock temperature too high Reduce temperature slowly

ID grooves Mandrel is coated with material Clean mandrel

ID wavy surfaceScrew clearance set improperly Adjust clearance

Puller drive slipping Adjust or replace puller drive


OD burn streaksMaterial hung up on die Clean die

Temperature too high Reduce temperatures slowly

OD uneven circumference

Too much air pressure on puller Reduce air pressure

Insufficient air pressureCheck air pressure and all connections

OD discoloured Stabiliser level too low Check stabiliser level

OD pock marks

Air bubbles adhering to pipe in flotation tank

Install wiper in tank

Improper adjustment of spray rings that surround water tank.

Readjust spray rings

OD oversized

Air supply too high Adjust air supply

Insufficient water supply Increase water supply

Pipe hot when measuredAllow pipe to cool before measuring

Wall too thick

Mis-adjusted die bushingAdjust die bushing to achieve uniform thickness

Wrong die set-up Use correct set-up

corporate training and planning extrusion. corporate training and planning film blowing, mono- and...

Documents

planningcorporate training

extruderscorporate training

number of layer

hauloffcorporate training

extruderslayer head

compatible3layer head

polishing rolls

blown film process