Textile Finishing Different Types of Mechanical Finishes for Textiles

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Textile Finishing: Different Types of Mechanical Finishes for Textiles

Topics: Finishing, textile basics By: Prasanta Sarkar

In the previous post classification of textile finishes and treatment are listed This post !ill cover

about those treatments"

1. Calendering

# simple device !hich simulates the effects of calendaring is the domestic iron $ot ironing

makes garment smooth flat by removing its crinkles and creases Besides making the fabrics freefrom creases by calendaring,

• it is possible to raise the luster of the fabric,

• make it compact by closing the threads,

• impart a soft feel and %thready& or

• linen like appearance to it

It reduces the yarn slippage as !ell as thickness of the fabric by varying the calendaring

operation

The need of calendaring arises mainly because the fabric !hen it is !et processed and dried, is in

the least lustrous state and its surface is not smooth because of presence of highly crimped and!avy threads To meet this need the fabric is passed bet!een the rollers or ba!ls of a machinetermed %'alender& and this mechanical process is called calendering

Different types of calenders:

Ordinary Calender: #n ordinary calender consists of a series of hard and soft rollers or ba!ls

mounted vertically in a robust frame and the fabric is passed bet!een the rollers $ard ba!ls are

made of polished metal and soft ba!ls are made of compressed cotton or paper or !ood

Swizzing calender: This is an ordinary calender usually !ith ( ba!ls !hich run at the same

peripheral speed so that there is no slip bet!een them

Friction calender: )hen maximum increase of luster, higher gloss and greater closing up of the

fabric is desired, a calender in !hich one ba!l is made to rotate faster than the other and !hich is

heated and polished, is used Friction calendars are used for finishing lining, shirting, and printedclothes

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Chasing Calender: In this calender five ba!ls are used #ll ba!ls run at a same speed This

operation of chasing produces a %thready& or linen*like appearance together !ith a soft fell

E!ossing Calender: In embossing calender fine lines are embossed on the cloth +mbossing

brings about a high degree of luster on the cloth, makes it smooth and flattens it amask effect

can also be produced on cotton cloth by this process, but effect of embossing is temporary

". Sanforising

# method of producing unshrinkable cotton fabric is to give it a thorough !ash in a !ashing

machine so as to allo! it to shrink freely and then dry and finish it !ithout stretching Thismethod ho!ever is not reliable and not suitable for commercial production

#. $aising

-aising is a process of lifting of a layer of fibres from the surface of the fabric so as to form a

hairy surface or pile The process imparts a !arm and soft handle to both on the !oven andknitted fabrics. in fact, the formation of a pile on the fabric can make it exceptionally soft The

pile also includes a large amount of air and since air is a bad conductor of the heat, the raisedfabrics feel vary !arm as !ell as soft

In the early days, only cotton and !oolen fabrics !ere raised, but no! besides these fabrics,man*made fibre fabrics also raised If the fabric contains a !oven or coloured pattern, the !eave

and pattern get subdued on raising and various colour blends

It is easier to raise the fabric in the !et state than in dry state Therefore, moist raising is most!idely adopted

%. &apping

In napping the surface of the cloth is raised, cut even and smoothed by a napping machine kno!n

as planetary napper

'. Shearing

Shearing means removing or taking off fibre ends by cutting It is carried out to cut fibres of

random length to produce a level pile and prevent pilling in case of synthetic fibres by resulting

of the height of the fibres particularly to produce clean staple fibre fabrics /apped fabrics are

mostly sheared

0nitted fabrics are sheared on a machine having a single cutting head per unit !here in case of

!oven fabrics multiple sheared are used The pile heights are regulated by ad1usting the distance bet!een the cloth rest and rotary blade

(. S)eding


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)hen a vary mild effect of raising is re2uired a special type of machine called sueding machine

is used This consists of a vertical set of small diameter rotating rollers covered !ith an abrasive

surface such as sand paper or emery cloth There is a rubber covered pressure roll !hich pressesthe fabric against the abrasive covered cylinder The abrasion of fabric surface takes place !hen

the fabric is open !idth presses bet!een the pressure roller and abrasive covered cylinder # vary

sort pile thus raised according to the pressure of the fabric against these rollers !hich rotate in adirection of opposite to that of the fabric

(. Setting and *eat+setting

uring manufacturing processes like spinning, !eaving or knitting, the fabric is sub1ected tostresses and strains and release of these distortions in fabric leads to distortions in fabric structure

and !oven design and also uneven shrinkage The purpose of setting is to stabili3e the !oven

structure of the fabric in a regular and permanent manner by relaxing the stresses The effect is bought about by agencies like heat, moisture, and pressure and generally no chemicals are used

in the process

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Textile Finishing Different Types of Mechanical Finishes for Textiles