Process of Mercerizing Knitted Fabrics

Mercerizing is an additional process which can improve the physical and chemical properties of knitted fabrics. For dyeing knitted fabrics, mercerizing is before dyeing. Mercerized fabrics are more suitable than unmercerized fabrics. Mercerizing depends on the buyers’ requirements, which is not common for cotton fabrics. It is done for the sophisticated fabric. The machine is vertical type which consists of vertical washing chamber.

Types of mercerizing process: Three stages of the products can adopt mercerizing
>Grey mercerization (Knitted fabrics before dyeing)
>Fabric mercerization (Yarn dyed fabric)
>Collar & Cuff mercerization.

Frequency of mercerization: Mercerizing process can be classified into single mercerization and double mercerization.

Process of mercerizing knitted fabrics:
1)Fabric entered in mercerizing machine
2)Impregnation in reaction chamber
3)Hot wash
5)Hot wash

Hydro Extractor Machine for Dyeing Knitted Fabrics

Hydro extractor machine is the first sequence of dyeing knitted fabrics. After dyeing being completed, knitted fabrics are hold for a while before hydro extraction. Hydro extractor machine is vital for de-watering process.

Functions of hydro extractor machine: Hydro extractor machine uses centrifugal extraction to remove excess water from knitted fabrics. About 65% water is removed by hydro extractor machine which spends 5-10 minutes.

Procedure of hydro extractor machine: Hydro extractor machine looks like a round basket which is made of steel. It has amount of holes on the down side of basket. Put the wet knitted fabrics into the hydro extractor, then water is removed by centrifugal extraction. Extract water is drained out through the holes.

Nowadays, various types of hydro extractor machine are available in the market. People can choose what they need according to their own requirements.

Process of Manufacturing Knitted Fabrics

Knitting is the interlocking of one or more yarns through a series of loops which is the main activities for producing knitted fabrics. In every mill, a sequence is maintained in production processing. In every step, person should be responsible for the best production. The followings are the process of manufacturing knitted fabrics.

Firstly, a production is supplied to knitting manager from the merchandiser, according to the requirements of consumers. Then he informs or orders production officer about it and provides the schedule for producing targeted production.

1. Getting the analysis from knitting manager, design and draw a cam setting for producing the desired fabrics.

2. Getting the information, production officer informs technical who is in charge and knows about machine which the production will be run.

3. Technical in charge calls for leader of mechanical fitter troops who also take decision about machine for production considering machine condition, machine types, production capacity and maintenance complexity.

4. Production officer adjust required stitch length and grey G.S.M for getting final G.S.M., cooperating with experienced mechanical fitter.

5. Supervisor checks production regularly and makes operator consciously about finishing tin due time who is also maintain daily production report sheet and responsible to inform the production of that day to knitting manager.

6. Operator runs machine in high attention in case of faults in the fabrics. Any faults are found, he will call for the mechanical fitter who is in duty. Then, mechanical fitter fixes it or informs it the technical in charge. The technical will take necessary to remove the problem.

7. During production time, quality department also checks the fabric. If any faults are found, they will inform it to the technical in charge. Technical also takes necessary steps for reducing the faults in knitted fabrics.

8. When knitted fabrics completed, knitted fabrics will be sent for quality check. If the fabrics pass the quality, they will be sent for the next process.

Definition and Types of Knitted Fabrics

Fabrics are produced from a set of warp or weft yarn. Weaving and knitting differ for interlacing techniques of yarn. In weaving, warp and weft yarn are used for producing woven fabric. For knitting, a series of yarn in warp or weft directions are made of fabrics.

Knitting is defined as the process that sets connect loops from a series of yarn in warp or weft direction to produce fabrics. Various knitting machines are used to perform knitting. In general, knitted fabrics are classified into warp knitted fabrics and weft knitted fabrics.

Warp knitted fabrics: In warp knitted structure, different thread and the number of thread is made of each loop in the horizontal direction. Fabric is at least equal to the numbers of loops in horizontal row.

Weft knitted fabrics: Use one thread runs in horizontal direction to make a horizontal row of loops. The structure of weft knitted fabrics is different from that of warp knitted fabrics. Weft knitted fabrics have worldwide popularity.

In daily life, different knitted fabrics are used. Depending on the design of fabrics, knitted fabrics are classified into following types.

>Single Jersey
1. Plain Single Jersey
2. Single Jersey with Lycra
3. Single Lacoste
4. Double Lacoste
5. Single Pique
6. Double Pique
7. Polo Pique
8. French Terry
9. Terry with Lycra
10. Fleece
11. Fleece with Lycra

>Double Jersey
>Rib Fabric
1. 1×1 Rib
2. 2×1 Rib
3. 2×2 Rib
4. Lycra Rib
5. Flat Back Rib

>Interlock Fabric
1. Plain Interlock
2. Drop Needle Interlock
3. Interlock with Lycra

>Collar and Cuff
1. Plain Collar or Solid Collar
2. Shaving Collar
3. Jacquard Collar
4. Tipping Collar
5. Race Collar
6. Stripe Collar

Knitting machines also develop various types of decorative design. In modern times, auto stripe knitting machine is used to produce multi color stripe fabrics, which cannot be produced by normal knitting machine.

Knitted fabrics have different properties. Knitted fabrics depend on the atmospheric condition of the country.

Faults of Knitted Fabric in Production

Loop formation produces knitted fabric which should be careful. Various types of faults can be found in knitted fabric, which caused by fabric rejection. Find out defects of fabric during production. Then, steps can be taken to remove them from the next knitting production process.

In practical: The followings are the faults which could be found on the knitted fabric.

Hole Mark
>The yarn breaks in the rejoin of the needle hook during loop formation.
>Caused by yarn breakage or cracks.
>The yarn is not correct on regarding structure, gauge, course and density.
>Badly knots or splicing.
>Badly set of yarn feeder.

Needle Mark
>Needle marks come along the fabrics when a needle breaks down.
>If a needle or needle hook is slightly bends, then needle mark comes on the fabrics.

>Buckling of the needle latch.
>Yarn tension variation during production.
>Low G.S.M fabric production.

Sinker Mark
>Sinker may corrode for abrasion. So it cannot a new loop and result in sinker mark coming.
>Sinker head bends. Then sinker mark comes.

Drop Stitches
>Yarn is not feed properly during loop formation.
>Using defective needle.
>Take down mechanism is too loose.
>Insufficient yarn.
>Set yarn feeder badly.

Oil Stain
>When oil lick through the needle trick then it pass on the fabrics and make a line.

Rush Stain
>Rush in the machine.

Pin Hole
>Break down or bend of the larch causes pin hole on the fabric.

Grease Stain
>Improper greasing in the machine.
>Excess IF greasing

> when an empty needle with an empty needle with close latch runs into the yarn feeder and remove the yarn out of the hook of the following needles, then cloth fall out occur after a drop stitch.

>Yarn fault
>Different micro near value of fiber content in yarn.
>Different luster and dye affinity of fiber content in yarn.
>During spinning different similar classes of fiber is mixed specially in carded yarn and these fibers have similar characteristics.
>In draw frame different similar classes sliver is mixed and make one sliver.

Yarn Contamination
>Yarn contains foreign fiber. And the foreign are remained in the fabric even after finishing.
>Lot mixing and count mixing.

Fly Dust
>In knitting section too much lint or short fiber is flying to and fro that are created from yarn due to low twist as well as yarn friction. This lint may adhere or attached to the fabric surface tightly during knit fabric manufacturing.

Yarn Faults
>Different yarn faults
>Yarn count variation
>Thick/Thin place in yarn

Knitted machine should have perfect conditions. Faults are not allowed to exist in needle, sinker, feeder and other equipments.

Silk Composite Air Layer Knitted Fabrics Production Process

Silk knitted products not only with moisture, breathable, lightweight, health and other characteristics, and better than woven silk elastic, anti-wrinkle resistance and washability.

Currently, the market is more popular composite air layer thermal underwear fabrics of cotton and chemical fiber mainly based raw materials, relatively small silk material, for which the development of a series of complex air layer containing silk fabric, mainly from the core material processing, weaving process, dyeing process improvement and innovation aspects of the product by the consumers.

1. Pilling resistant core material processing

Core common air layer fabric used without anti-pilling treatment during wearing due to friction, static electricity and other reasons, the core material is easy to drill out, forming a strip of silk thread, seriously affecting the taking effect. In response to this situation, on the basis of past elastic network processing technology, to carry out anti-pilling core processing, but does not affect the core material shrinkage and fluffy on the basis of the core material processed by the network than ordinary yarn better bulkiness.

Filament interlacing is Shuli air out of the “pigtail” section, where smooth no section does not affect the weaving, while the unpaid portion of the elastic fiber network through the air opening, resulting in a better fluffy, with more good warm effect. Processed by interlacing stretch silk with good cohesion of the post office network, under the ordinary force, several stretch is not easy to loose. Plus appropriate organizational weaving, overcome the common core wire is easy to drill stretch velvet, silk thread from defects.

2. weaving process

Because silk texture rather hard, toughness and bending resistance, is more prone to defects than the average of yarn during weaving, such as triangular eyes, cloth and other irregularities. Difficulties silk weaving knitting process that controls the process of tension, too easy to fall off, it will cause too much wear and tear on the loom parts, oil is also easy to fluff. By constantly adjusting the machine, comparing the best weaving process chosen, the following air layer of silk straight example.

a) Device Parameters

Models: paddle UP372 double jacquard knitting machine

Machine No.: 28-pin /25.4 mm

Tube diameter: 762.0 mm (30 “)

Large ones: 72 F

b) Material selection

Fabric surface and the inner layer are selected for 4.4 / 4.9 tex silk × 2 (40/44 D × 2), the core selection 22.2 tex (200 D) polyester.

c) threading mode

24 F for a loop, the first 1,4,7 … 22 F syringe full into the ring, penetration 4.4 / 4.9 tex × 2 silk; Section 2,5,8 … 23 F dial needle into the whole circle, corresponding drafted pattern at syringe needle on × tuck, penetration 4.4 / 4.9 tex × 2 silk; section 3,6,9 … 24 F corresponds to the drafted pattern × tuck at syringe needle, penetration 22.2 tex polyester.

d) drafted pattern

Its artistic conception shown in Figure 2.

Figure 2 drafted pattern

Flower width of 12 vertical lines, flowers high as eight courses. Road cycling is 24 large ones, because the use of 28-pin /25.4 mm machine-woven, more delicate fabrics, fabric patterns in order to make the effect more prominent, using the same needle for two consecutive pin tuck. Polyester alone all the way into and tuck at a circle, thus reducing the polyester in the middle of moving to avoid pilling, pilling. The fabric results in Figure 3.

Figure 3 fabrics positive effect diagram

e) yarn tension adjustment

Because silk has good toughness, silk weaving to control the tension. Tension too much machine and knitting needles will cause excessive wear and tear, too will fall off when the output of silk yarn, silk general tension control at 3.92 ~ 5.88 cN appropriate. Polyester yarn tension as small as possible, the general control 1.96 ~ 2.94 cN appropriate.

f) cloth adjustment

When weaving, if the tension is too small cloth, cloth easily float, not normally a circle, cloth should be appropriately increased tension, but not too much, too much tension on canvas prone holes to be transferred fabric formation no hole prevail.

h) is adjusted with the cam cylinder and dial cam

Because silk has good toughness, weaving the fabric surface is easy to fluff, so to adjust the syringe and needle plate triangle triangle with them to dial needle and syringe needle into the ring at the same time, this silk into yarn tension is relatively stable, not prone hole.

3. Dyeing and Finishing

After air layer composite fabric weaving, but also after scouring, dyeing, setting and other finishing. When one side of the fabric dyeing inside outwards, to avoid sanding the front, in order to maintain a positive and smooth. With acid dyes, control time and temperature scouring, color fastness to achieve three or more.

Yarn Preparation for Knitting Fabrics

Yarn used for knitting could be grey or dyed. Yarn is the main raw materials for knitting fabrics. Yarn needs to be prepared for knitting. It cannot be used in directly after being collected from spinning. The ways which process yarn before loom are called as yarn preparation. Characteristics of knitting fabrics mostly depend on yarn preparation.

Necessity of yarn preparation: Various ways are used for preparing yarns. The followings are the necessities of yarn preparation.

1. Yarn preparation process can eliminate defects of yarns.
2. Preparation transfers yarns from spinning package to a convenient form of package which facilities the knitting.
3. Clean the yarn for better appearance and performance.
4. Have desired length of yarn in package.
5. Get fabric which has better quality.
6. Eliminate unwanted dust and hairy fibers.

Yarn preparation plays an important role for knitting fabrics.