LATEST TECHNOLOGY IN MECHANICAL FINISHING

Finishing is the last manufacturing step in the production of textile fabric.

Finish can be either chemical that change the fabric’s aesthetic and /or physical properties or change in texture or surface characteristics brought about by physically manipulating the fabric with mechanical devices. It can also be a combination of the two.

•Finishing

Mechanical (Dry) Chemical ( Wet)

In chemical finishing, water is used as a medium for applying the chemicals. Heat is used to drive off the water and to activate the chemicals.

•Mechanical finishing is considered a dry operation even through moisture and chemicals are often needed to successfully process the fabric. Mechanical devices are used in both categories-the major distinction between the two is what caused the desired fabric change, the chemical or the machine.

•Mechanical finishing uses mainly physical (mechanical) means to change fabric properties and usually alters the fabric appearance as well. It also encompasses thermal processes such as heat setting (thermal finishing).

Typical mechanical finishes include calendering, emerising, compressive shrinkage, raising, brushing and shearing or cropping, and especially for wool fabrics milling, pressing and setting with crabbing and decating.

DIFFERENT MECHANICAL PROCESS Calendering

Raising

Compressive shrinkage

Cropping

Emerising

Calendaring: Compression of the fabric between two heavy rolls to give a flattened, smooth appearance tot eh surface of the fabric.

Raising: Plucking the fibres from a woven or knitted fabric to give a nap effect on the surface.

Cropping: Cutting the surface hairs from the fabric to give a smooth appearance, often used on woolen goods where the removal of surface hair by a singeing process is not possible.\

EEmerising: Rubbing the fabric surface through emery roll, producing peach skin finish.

Compressive shrinkage:

The mechanical shrinkage of the warp fibres in woven fabrics so that shrinkage on washing is reduced o the desired level.

CUSTOMER REQUIREMENTS Aesthetic Smooth Luster RaisingFeel Soft handle Drape Functional Shrinkage Air permeability.

CALENDERING ObjectivesSmoothing the surface of the fabric Increasing the fabric luster. Closing the threads of a woven fabric. Decreasing the air permeability. Increasing the fabric opacity. Improving the handle of a fabric. example : softening. Obtaining gloss. Surface patterning by embossing. Consolidation of nonwoven. 

Normal gloss

A cold calendar A smooth flat fabric A lustrous surface

Chintz or glazing

Highly polished surface (chintz glazed) Bowl speed greater than the speed of fabric For very high gloss, the fabric is often pre impregnated with a

wax emulsion Often called friction calendaring.

Embossing

The heated top bowl of a two bowl calendar is engraved with an appropriate pattern which is then transferred to the fabric passing through the bowl.

Schreiner or silk finish

Silk like finish on one side of the fabric. Bowl contains series of fine embossed lines at an angle of 30 O

warp wise. Popular on curtains and drapes.

De-lustreing

This is commonly achieved by passing the fabric through the bottom of two bowls of a three bowl calendar, where these are elastic. However the steel bowls with a special matt finish have been manufactured that are very effective for this purpose.

Chasing

The fabric is threaded through the calender in such a way as to press the fabric against itself several time. It is common to use a five or seven bowl calender, the fabric passing through each nip of the calender in two or three layers.

SANFORIZING

Control shrinkage along the warp.Mechanical type finish.Based on compressive shrinkage principle.

Objectives

Minimize residual shrinkageStabilize fabric structure.Complete the surface treatmentImprove the hand of the fabric.

Functions

Moisturizing/Steaming with steaming rollers

Steam applies moisture to the fabric Moisture provides lubrication for compacting process

Conditioning of the fabric

Selvedge spreading, weft straitening

Functions

Compacting in rubber belt machine

Continuous shrinkage process

Dry/heat setting

Removal of excess moisture through drying Stabilizing on the shrunken fabric structure

DECATING

The process is also known as decating and is mainly carried out on wool by exploiting its elastic properties in hot and we conditions by the direct action of the steam on the fabric. This treatment gives the processes fabric the following characteristics:

Dimensional stability Setting of pile raising Reduction of possible glazing effect after calendaring Modification of the hand, which is much more consistent

after treatment Pre-stabilization to autoclave dyeing Increase fabric drape

Hydro setting   Hydro setting is so rarely used particularly to get fuller and softer handle on polyamides at 125-135c in autoclaves for 20-30 minutes.  It can be combined with dyeing or optical brightening.

Steam setting 

Steam setting can be done by saturated or super heated steam.

 

During steaming, uniform treatment can be ensured by initial sequence of alternate short steaming and vacuum application for 20-30 min at 130C under pressure.

Super heated steam can be used in stenters and setting time is 25% shorter than for hot air on account of quicker heating up rate.

Acrylic fibers have to be protested as some may under go excessive shrinkage or loss of handle.

Before the material is heat set, it should be thoroughly washed to remove spin preparations, lubricants, sizing agents and impurities as these are likely to be burned in drying heat setting making their removal difficult.

MR. AHMER ADNAN BALOCH

General Trends in Mechanical Finishing  Many general trends in the mechanical finishing area

follow those in other areas of the textile world. Many of the companies are consolidating and combining representatives in the market place.

Examples of this include the alliance of Gematex and Vollenweider to form Xetma and the merger of Sistig, Menschner, Hemmer, and Kettling+Braun to form m-tec.

  

Other trends include incremental improvements in machinery and monitoring techniques.

There is a noted increase in the degree of technology used to monitor machines both visually and otherwise.

Several vendors are featuring integrated visual digital cameras in which other areas fabric formation or coloration typically provide for greater flexibility and can be done with limited investment. Many vendors stressed flexibility and variation in the enhancements that could be obtained from fewer pieces of equipment. 

Finally, many vendors highlighted changes and modifications to equipment designed to reduce costs.

Energy savings, consumption data, and reducing required operator intervention were highlights in many vendors’ presentations.

  Following are some specific vendor highlights to elaborate

on theses trends. Other vendors may offer similar features. This is not intended to be exhaustive, but representative of general trends.

Calendering Machine (KLEINEWEFERS)“Calendaring is an operation carried out on a fabric to improve its

aesthetics”.

Purpose of calendaring is:  To upgrade the fabric hand and to impart a smooth silky touch to

the fabric. To improve the opacity of the fabric To compress the fabric and reduce its thickness. To impart different degree of luster to the fabric. To reduce yarn slippage. The mechanical finish is done for softness and shining of the

fabric or stiffness according to the nature of the chemical, this process is done after the chemical finishing as per buyer requirement. Speed of the machine is 10-100 m/min.

Calender Machine

Components of machine:

  Winder  Metal detector  Seam detector  Rollers (cotton, ryclon and steel) Anti static rod Oscillating roll Batcher sensor  cooling drum

Seam detector:

Function of seam detector is to bypass the seam. the latest calender machines provided with seam detector to avoide the damage of the bowl and cloth due to bad sewing of the two layers of fabric.

Metal detector: the fabric may

contain any metal particle after going through different mechanical processes the machine equipped with a metal detector the function of metal detector to detect metal particles as to avoid the damage of the bowl.

Anti static rod: some fabric may

produce static charges and may stick to the machine parts due to static electricity. Anti static rod is used to remove static charges and production increases.

Small winder: When we have to

calendar short width fabric and we can also run short width fabric with long width fabric.

  Oscillating roll: To avoid selvedge

overlapping on batcher.

Cotton roll: For soft finish the fabric is passed through cotton

bowl. This roller is made up of cotton. Steel roll:

To give smoothness and luster. The temperature is provided to steel roller about32-200C with help of electric heater as we increase the temperature shining will increases only used for cotton CVC and percale and PC.

  Ryclon roll:

When fabric passes through Reclon roll and steel roll giving smooth and luster effect is generated. When it runs with steel roll and reclon roll and cotton roll dull effect is generated. When it runs b/w steel and reclon gloss effect is generated.

  Cooling drum:

Cool down the fabric water circulates inside the cooling drum.

NIPCO L calendar

The star among calenders A textile finishing calender with two nips with

independant pressure settings, a revolution in calender technology.

The system allows, high glazing, softness, density control and other sales requirements in one calender combined.

The hydrostatic support elements of our NIPCO® L system are independently arranged in a 90° configuration, one active against a steel bowl, one active against a cotton bowl.

High glazing: increased pressure in the nip Steel/NIPCO RACOLAN at the same time slightly reduced glazing and softer handle, decreased pressure setting in the nip NIPCO RACOLAN/Cotton.

Elegant glazing and remarkable softness in handle: decreased pressure in the nip Steel/NIPCO RACOLAN at same time increased pressure in the nip NIPCO RACOLAN/Cotton.

PASSING OF FABRIC

THROUGH NIPS:

ANDRITZ KUSTER CALENDER

Three bowl Calender with S-Roll.

For technical textiles.

Three bowl Calender with Hycon.

For normal textile fabric with L arrangemet.

S-Roll features

Espacially for technical textiles such as parachute silk or high quality outdoor clothing have to eb calendered to attain a defined, low air permeability.

Steel tube rotates around the fixed axle.the cahmber facing the nip is hydraulically pressurised by oil that producess a linear pressure.

This ensures a infinitely variable and even line of force along the width of the fabric.

No friction is produced in the nip so the rolls rotates against each another are absolutely cylindrical.

HyCon Roll Features

In contrast with the swimming roll the hycon roll has a hydrostatic deflection control ans is mainly chosen when two different effects are to be obtained in one fabric passage.

2 roll execultion effects,such as gloss,high gloss,smoothnes,density or micro embosing can be achieved.

HyCon Principle

Deflection control. Variable line of force. Variable fabric width adjustment.

MR. DANISH HUSNAIN MINHAS

EMERISING Emerising (also known as sueding or sanding, in the USA) is a process in

which fabric at open width is passed over one or more rotating emery-covered rollers to produce a suede-like finish. Woven and knitted fabrics and also laminated fabrics may be emerised, the surface appearance, texture and handle of the treated fabric being altered according to the emerising conditions. Woven cotton denim fabrics may be given a suede-like finish while polyester and nylon microfilament fabrics have been given a peach-skin finish which can impart a soft luxurious handle, especially if chemical softening agents such as amino-functional polysiloxane softeners have been applied. 

The major change in the fabric after emerising is theproduction of a very low pile – that is, short fibres protruding from the fabric surface. The handle will differ according to the type of fibre(s) present, the fibre linear density and the intensity

Of the emerising action on the fabric. In general, the handle of a fabric is much softer after emerising and the softness can be greatly enhanced by using fine microfibres (<1 dtex f–1) together with chemical softening agents to give a peach-skin finish in which short fibres protruding from the fabric surface simulate the soft andle and appearance of natural peach-skin. merising of microfibre fabrics should be carried out prior to dyeing.

SINGLE ROLLER  Two ways of introducing goods to the grinding roller.Left: proximity;

right: tangential.consists of one abrasive covered metal roller and one rubber covered compressive or pressure roller.tha abration and cutting of the surface takes place in the nip formed b/w the pressure roler and the abrasive covered roller.used specially on the fabric with terry loops on the face that must be broken and also styles where fabric surface must effectively shaved.the machine icorporate a self cleaning dust exhaust and collective system.

MULTI- ROLLER: Operating speeds on multi-roller sueding or emerising machines are

generally higher on woven fabrics than on knitted fabrics; typically of the order of 12–15 m min–1 on microfibre fabrics, up to 15–25 m min–1 on spun yarn types of woven fabric, and 10–20 m min–1 on similar knitted fabrics. Precise tension control is required to transport the fabric through the machine at open width without folds or fluttering.

Xetma

Xetma is a Swiss / German corporation formed by the merger of Vollenweider and Gematex.

They were showing a unique machine for the processing of open width woven and knit fabric for hand enhancement and applying softness without excessive surface hairiness.

The foundation for this machine is a rotating cylinder in a classic napper configuration. However, in lieu of individual covered rollers, there were three rollers in a tri star configuration at each position of 12 positions around the cylinder.

Each of these three rollers can be covered by various media such as emery cloth, brushes, or napper wire.

This allows for very quick style change from one media to the next and for novel finishes to be obtained by combining various media on the same fabric such as raising and emerising.

Overall, this one machine is capable of five technologies including raising, raising / emerising, emerising, emerising / brush-sueding, and brush-sueding. Napping can be accomplished with a 1:1 or 1:3 pile:counterpile ratio.

5 technologies in one machine:

XR raising XRE combined raising & emerising XE emerising XEB combined emerising & brush sueding XB brush sueding

maximum flexibility through easy re-setting between the individual technologies within 2.5 hours

meeting of all demands for the mechanical surface finishing with only one machine system

LAFER SUEDING MACHINE: 

Superior sueding effect: no streaking - no hairyness -

Lafer machines are equipped with the new sueding drum configuration allowing to use either abrasive brushes (warm effect) Carbosint" diamond rollers (cool effect) (conversion kit available separately).

When using the UltraSoft brush sueding mode, special metal plates (patented Delta system) allow to keep the fabric well spread at all times avoiding channeling and streaking.

On conventional machines without these supports, the lengthwise tension causes a downward pressure that distorts the brush bristles causing channeling (lengthwise creasing) which on most fabrics will produce lengthwise streak marks and “center to selvedge differences”.This will limit the range of fabrics that can be processed.

On the UltraSoft, the Delta plates support the full tensioning range required for all types of fabric construction in order to maintain the ideal orientation of the brushes and avoid channeling.

  Higher lengthwise tension settings

will produce a cleaner cut short pile sueding effect while lower tension settings will leave a longer surface pile.Conventional systems without the Delta support plates are very much limited in the lengthwise tension settings hence the range of fabrics are limited.

2) All types of fabric structures elastic and non can be processed

The Lafer machine (Ultrasoft mode*) is equipped with 4 load cells positioned in critical spots of the machine that are essential for processing even the most delicate knits or lycra based . (*ultrasoft mode available as option on Microsand).

A specific "knit fabric operating software" allows to treat these "difficult fabrics" with ease.A separate "woven fabric operating software" (Microsand mode) leads to the best results always. Other machines cannot treat all types of fabric without accepting compromises on quality and/or production.

The patented Delta system with the UltraSoft brush mode allows to cover the maximum drum angle leading to greater contact area between fabric and abrasive brush.Other machines without the Delta system are forced to run at slower speeds and lower tension settings in order to avoid problems (streaking especially on knits, etc) and in any case produce more hairyness than Lafer.

3) Higher production

4) Longer emery lifetime The exclusive "Carbosint"

diamondlike emery developed by Lafer allows significantly reduce machine stops for emery replacements.

There are Microsand endusers that have been able to exploit a full drum of Carbosint emery for @ 4 million meters! We know of no other system that can do better than Lafer.

5) Flexible setting modes: rollers all clockwise / all counterclockwise / half&half

On the Lafer machine, you can set various operating modes in order to create different sueding effects.

6) Suregrip transmission system

A new differential drive system with timing belts allows to exploit the maximum energy available.

7) Advanced chamber cleaning system

The new sueding technology using abrasive brushes or diamond emery creates very fine dust compared to conventional sandpaper which creates larger particles that are easier to eliminate.

The sueding chamber is enclosed in order to create the necessary pressure to enhance the suctioning efficiency.

The sueding chamber is equipped with an exclusive vent system to help remove the sueding dust and keep the machine cleaner in order to avoid fabric contamination.

8)Supplementary brush at outlet

At the outlet of the sueding drum, a special finishing brush orients the pile and enhances the sueding effect on woven fabrics.

9)Separate fabric cleaning unit

On top of the machine there is a very efficient unit equipped with brush and beater connected to the suction unit.Just compare the above 9 points to other machines and it will be easy to understand why Lafer is the No.1 sueding technology

RAISINGDIFFERENT RAISING ROLLER RATIOS Beside the traditional pile/counter-pile procedures at the ratio 1:1

and the full felting procedure with only pile or counter-pile rollers, Xetma Vollenweider was the first manufacturer to develop raising technologies with different ratios of pile and counter-pile rollers. Depending on the number of raising rollers in the drum, pile/counter-pile ratios of 1:2, 1:3 or 1:4 are realized.

The higher the number of counter-pile rollers, the shorter and denser the raising pile turns out. This brings decisive advantages in the working of woven and knitted wears of which the base is to be intensively raised and made denser. The optimal ratio of raising rollers, specifically designed for the individual article, provides the user with higher production quantities at shorter running times.

Twin system XR     patented special drum with arrangement of cleaning rollers

and dedusting inside the drum

maximum wrapping of drum allows 2 x 20% higher raising performance compared to traditional machine systems, with essentially less space requirement

raising of woven, knitted fabrics - especially tubular - as well as non-wovens, with highest performance

saving of raising passages through optimal use of working roller per passage

possibility of different raising technologies per drum

equal raising effect from the centre of fabric to the edge

• quality ensuring raising system (QSR®) for optimal fabric guiding during the entire working process

• minimizing of shrinking effect by parallel working of both fabric sides per drum

Lafer SpA has become the largest manufacturer of raising and shearing machines world-wide while providing a variety of different solutions for raising all kinds of fabrics whether knit or woven.

Double or single drum configuration

Single drum raising machines with 24, 28, 32 or 36 raising rollers and double drum machines with 24, 28 or combined 24/36 raising rollers are available in various widths in order to satisfy different production requirements. Combined raising and shearing units (GLC) are also available.

State of the art controls simplify the raising process

Unlike conventional raising machines equipped with simple control units, Lafer has developed an exclusive system combining both PLC and industrial PC system with large touch screen colour video with the objective of making raising a much easier process compared to other machines.

Advantages

· 1 million raising programs storage capacity. · On-screen troubleshooting guide with photos and instructions (over 100

alarms included). · The machine can be connected to a network through ethernet card

(optional) so that production data can be monitored from a remote computer.

· An optional modem allows troubleshooting directly from Lafer headquarters.

· Electronic fancy brush synchro control prevents possible damages to raising fillet caused by non synchronized raising fillet cleaning brushes.

Precise fabric tension control

Fabric tension on the raising drum is one of the key parameters to achieve the desired raising effect.

Fabric tension is set on the touch screen and is controlled by the computer.

Automatic minimum tension control by load cells (Patent Pending)

Optional load cells placed at the entry and exit of each drum allow to automatically maintain the minimum fabric tension set regardless of the raising energies.

This prevents the fabric from becoming too loose at the drum entry and exit points allowing optimal raising on the entire drum and avoids bar marks, weft distorsions or other inconveniences.

Uniform raising

Special pressure rollers are fitted on the entry and exit draw rollers in order to prevent fabric slippages and ensure perfect raising uniformity.

Adjustable drum speed/direction (standard)

The drum has adjustable speed and can rotate in both directions compared to the fabric. On the twin drum machine drum speed and rotation direction can be varied separately.

Raising energies always constant.

An electronic system maintains the raising energies constant while varying the fabric or drum speed.

MR. Sakhi

SHEAING MACHINES EXCLUSIVE HIGH PERFORMANCE CONFIGURATION

The"Diablo" version allows to shear polar fleece and terry velours up to double the speeds of conventional machines with completely automated adjustments

The know-how developed while serving the most qualified Companies worldwide has lead to today’s wide range of machines that can operate independently or in modular lines for shearing and raising/shearing customised according to different fabric structures and production requirements.

Exclusive anti-vibration shearing cylinder The Lafer shearing cylinder is of a unique design, with a

special anti-vibration technology, that ensures a perfect rotation in order to achieve an optimal cut. The cylinder revolves at a speed adjustable from 500 to 1500 rpm.

Maximum shearing precision

The shearing precision on the Lafer machine is 0.03mm, whereas most other machines have a precision of only 0.1mm. This increased precision, gives a great advantage of much better control and a better shearing effect and quality

Sensors continuously monitor the fabric thickness 

(Sensitivity 0.03 mm) and the shearing and velveting parameters are automatically adjusted when the seam passes by adding the degree of shearing and velveting to the fabric thickness

Shearing rest & ledger blade alignment

The alignment of the shearing rest & ledger blade is maintained constant when the shearing height is varied thanks to the particular “compass” movement.

Automatic fabric tension control

The fabric tension set between the draw rollers is automatically monitored by highly sensitive load cells hence it is possible to shear in continuous mode and with minimum tension every kind of woven, knit and stretch fabrics.

In order to prevent the fabric from slipping or dragging on the velveting brush when a strong action is set, the 2 draw rollers have a wide contact angle of the fabric to ensure the correct grip.

Automatic lubrication

It is critical to maintain the shearing cylinder evenly lubricated in order to ensure uniform shearing and the Lafer offers maximum reliability. The Lafer system can be programmed how often to oil the felt and how much oil is to be distributed. When the oil finishes the computer will give an alarm

All functions are under control

The Lafer shearing machines are driven by AC motors controlled by sensor less vectorial inverters and the electronic control system is equipped with:

 · PLC programmable logic controller for the machine automations

and alarms.  · Operator interface by industrial PC using colour touch screen

technology for setting and storing all operating parameters. Shearing parameters of each fabric can be memorized (over 1 million recipes can be stored) hence the desired effects can be easily and quickly reproduced.

 

Optima XS1 SHEARING  

shearing of all kinds of knitted and warp-knitted as well as of medium and high pile woven materials

automatic back-traveling when machine stops, in order to avoid shearing starting marks

automatic shearing starting process for fine adjustment and control of shearing result

high-precision setting of the shearing table using a new kind of setting mechanism

automatic programs for keeping the desired pile height constant

automatic lubrication of shearing equipment for maximum

serviceable life

automatic swiveling away of shearing, polishing and triggering units as well as brushing unit during seam passage

SANFORIZING

The shrinking process takes place between the rubber belt & the heated shrinking drum.

The pressure Roller presses the rubber belt against the shrinking drum and the belt is stretched.

When the pressure of the roller is relieved, the belt shrinks again.

The fabric inserted between the rubber belt and the drum has to follow the shrinking of the belt and is itself shrunk.

Monfortex and Toptex:

Monfortex and Toptex shrinkage units for woven and knitted fabrics and in special versions for denim are preferred by quality-oriented finishers worldwide.  

The main benefits are the outstanding performance values for achieving a reproducible minimum residual shrinkage.

This is also underlined by the specifications of international shrinkage standards that in most cases are far surpassed by Monfortex and Toptex ranges.

  And even better: Minimum residual shrinkage values and

highest reproducibility are achieved using environmentally safe process engineering.

WORKING PRICIPLE The shrinking process takes place between the rubber belt and the

heated shrinking cylinder. The pressure roll presses the rubber belt against the heated shrinking cylinder which is thereby stretched. When the pressure of the roll is relieved, the belt retracts again.

The fabric between the rubber belt and the cylinder has to follow this retraction of the belt and is thereby shrunk. Every change in the rubber belt pressure changes the fabric shrinkage.

The higher the pressure, the greater the shrinkage.

Fabric Heated shrinking cylinder Rubber belt

If the shrinking units are arranged in tandem, the service lives of the rubber cloths are up to 25% longer (depending on the application)

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