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:دور ا

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• 1- C. A. Lawrence “Fundamentals of spun yarn technology”. CRC Press.

Boca Raton. 2003.

2- W. Klein “The technology of short-staple spinning”. The Textile

Institute. Manchester. 1998.

مركز نشر . ”اصول و تكنولوژي ماشين هاي شانه، كشش و نيم تاب“مجيد صفر جوهري - 3.1382. تهران. دانشگاه صنعتي اميركبير

مركز نشر دانشگاه صنعتي . ”اصول و تكنولوژي ماشين ريسندگي رينگ“مجيد صفر جوهري - 4.1384. تهران. اميركبير

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)'#&% ر$#"! ا ف

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,+ ز(!Combing

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:اهداف شانه زنيحذف درصد معيني از الياف كوتاه -1

حذف نپها و ناخالصي هاي باقيمانده در الياف -2

مستقيم و موازي كردن الياف -3

، يكنواخت تر، مقاوم تر، ظريفترامكان ريسيدن نخي جالي بيشترو با تميز تر

به طور متوسط ظريفتر از الياف مرغوب (noil)بايد توجه داشت از آنجا كه ضايعات شانه زني .الياف مي گردد (micronaire)هستند، شانه زني سبب افزايش مقدار ماكرونير

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Sequences of a combing cycle <=ا>6 ی: 6789 ,+ ز(! 5 1234 ,+ 0/.- ا

)شامل چندين فتيله كنار هم(تغذيه طول معيني از اليه الياف -1

گرفتن انتهاي اليه الياف توسط واحد نيپر -2

شانه زني سر آزاد الياف توسط سيلندر شانه -3

پيوند زني سر الياف شانه شده به الياف شانه شده قبلي و جداسازي -4

وارد عمل شدن شانه فوقاني به هنگام جداسازي جهت شانه زني انتهاي الياف -5

تميز كردن سيلندر شانه از ناخالصي ها و الياف كوتاه -6

.گفته مي شود (nip)هر سيكل شانه زني يك نيپ

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1 2

3

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Cylinder comb• 9?ر ,+

•Half-lap comb

جداسازي ضايعات : وظيفه•

)Noilنويل (شانه

داراي چندين رديف سوزني•

تغيير تراكم و ظرافت رديف •

هاي سوزني از ابتدا به انتها

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Around 40 to 60% of noil is removed by top comb

!)@A +, •Top comb

Top comb may get damaged very fast. Even 4 ro 5 needle damages will

result in slubs in the webs. So the top comb maintenance is very

important to produce good quality yarn.

Maintenance:

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Cleaning:

By hand or automatically with a jet of compressed air.

The density of needles in the top comb depends on the fibre micronaire , the

lap weight and fibre parallelization in the lap.

If the fibre Micronaire is less than 3.6, number of needles per cenitmeter in top

comb can be 30.In general for fibres above 3.8 Micronaire, 26 needles per

centimeter is used.

Density:

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BCDE Fوا •Nipper unit

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/G H I :J?K •Detaching rollersا

جنس•

حركت دوراني •

)غلتك بااليي عقبي(حركت انتقالي •

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LMNO :J?K •Feed roller

در هر سيكل، دنده رچت سر غلتك تغذيه به اندازه يك دندانه دوران داده

.مي شود و سبب حركت غلتك تغذيه مي شود

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(Forward feed / concurrent feed)تغذيه موافق -1

در تغذيه موافق، تغذيه اليه زماني صورت مي گيرد كه نيپرها به سمت غلتك هاي جداكننده در حال

.حركت هستند

:دو نوع تغذيه در ماشين شانه وجود دارد

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(Backward feed / counter feed)تغذيه مخالف -2

.در تغذيه مخالف، تغذيه اليه در زمان بازگشت نيپرها به منطقه شانه زني صورت مي گيرد

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•Web pan

Older web pans

New web pans

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P5 •Degree of combing ,+ ز(!

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Let us assume that the following cotton is used:

2.5% span lenth = 28 to 30 mm

uniformity ratio = 50 to 53%

FFI % = 6 to 14

Micronaire = 3.8 to 4.2

fibre strength = 24 to 28 gms/tex

The quality requirement for counts 30s to 40s, is to meet 5% uster

standards in U%, imperfection, strength and classimate faults.

The amount of noil to be extracted may be around 15 to 18%

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Comber timing chart• دیام ز4(! 1234 ,+

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فRS تUVW رXY The noil theory developed by Charles Gégauff and described

The effects of detachment setting and feed rate on the elimination of noil .

The correlation between feed amount and noil percentage with either forward or backward feeding.

Gégauff Noil Theory

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Z to E belonging to Fig. 1s to p belonging to Fig. 2-5

Z nippers;

A detaching rollers;

B fiber fringe protruding from the nippers;

K combing segment;

Edetachment setting, i.e. distance between the clamping line of the

nippers and the nip line of the detaching rollers;

S feed amount (mm) moved per combing cycle;

M longest fiber in the staple (mm);

A fiber ≥ E;

B fiber = E - S;

C fiber < E - S;

p noil percentage.

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Fig. 1 – Position of the nippers relative to the detaching rollers at the closest

approach (detachment setting E) during backward feed

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During the detaching stage the nippers are located at their closest spacing relative to the detaching rollers (Fig. 1), which draw off all fibers extending to the nip line, i.e. all fibers longer than E. This length E can be entered in the staple diagram (Fig. 2) as a line m-n. All fibers to the left of the line m-n pass into the combed sliver (hatched area AmnC)

Noil elimination with backward feed

Fig. 2 – Combing out with backward feed

(the staple diagram is shown)

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As the nippers retract towards the combs, the feed roller shifts the fiber fringe (initially with length E) forward through feed amount S. The fringe projecting from the nippers is now presented to the circular combs with length E +S (Fig. 3). All fibers shorter than E +S are carried away by the circular combs because they are not clamped. They pass into the noil .

Fig. 3 – Combing out the fiber fringe

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In the staple diagram (Fig. 2), this length can be entered as line q-r. In this stage all fibers to the right of the line q-r are combed out into the noil (area qBr) In the region qmnr it is therefore a matter of chance whether the fibers remain in the fringe or pass into the noil. Accordingly, a division can be made based on the mean fiber length represented within this area, and it can be assumed that the trapezium AopC represents fibers transferred to the combed sliver and the triangle oBp represents those passing into the noil. The dividing line between these areas has length E +S/ 2 .

Fig. 2

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Since in similar triangles the areas are in the same ratio as the squares of the sides, and since the noil percentage is based on the ratio of weight of waste to weight of feedstock, the following relationship can be assumed:

2

2

2

2

100 100

2

oBp ( op )p%

ABC ( AC )

S( E )

M

= × = ×

+

=

Fig. 2

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After the detaching stage has been completed, all fibers longer than E

have been carried away with the web. Since there is no feed step during

the return stroke of the nippers, the fringe is presented to the circular

combs with length E.

Noil extraction with forward feed

Fig. 4 – Position of the nippers relative to the detaching rollers at

the closest approach during forward feed

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During the following combing cycle all fibers shorter than E pass into the

noil; this is represented in the staple diagram (Fig. 5) by the area qBr.

Feed occurs during the subsequent forward stroke of the nippers, during

which the fringe is increased in length by the distance S. At the next stage,

that of detaching, the detaching rollers take at least all fibers longer than E

(Fig. 4, fibers a) into the combed web.

Fig. 5 – Combing out with forward feed (staple

diagram).

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However, as feeding occurs at this stage, fibers b of the original length (E -

S), i.e. shorter than E by the feed amount, are now moved forward to the

nip line by feed through distance S. That is why fibers longer than (E - S)

are now carried away into the combed web, and trapezium AmnC

represents these fibers.

Fig. 5 – Combing out with forward feed (staple

diagram).

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In this case also, the figure qmnr can be divided according to the mean fiber

length by the line op (E - S/2), and thus the following relationship can be

derived as before:

From the two derived relationships it follows that where backward feed is

used, noil is increased as the feed distance is increased, whereas in forward

feed noil is reduced as the feed distance is increased.

2

2

2

2

100 100

2

oBp ( op )p%

ABC ( AC )

S( E )

M

= × = ×

−

=

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From the preceding section it will be seen that with forward feed not only will shorter fibers be passed into the combed sliver (E -S instead of E), but also the quality of the combing operation itself must be different. Consider a fiber having a trailing end laying just in the bite of the nippers: During the forward movement of the nippers, with forward feed, this fiber passes into the combed web without any change, because the feed roller pushes it out of the nippers. In backward feed combing, this fiber will stay in the feedstock, because no feeding occurs during forward movement of the combs; the fiber is then nipped while projecting with the hook inside the nippers and combed once again. Therefore, if backward feed is used ,the circular comb rake through the fibers more often, so the quality of the combing operation is increased. This shows up in the elimination of impurities and neps. However, the difference is hardly detectable in modern high-performance machines of the latest generation .

The quality of the combing operation in forward and backward

feeding

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defY B]ghiت abc` _ ^[\ان اUVW MZت

• !"/G H -jk Detaching distanceا

The distance between the bite of hte nippers and the nip of the

detaching rollers.

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•!)@A +, ذmn opq Penetration dept of the top comp

•BCDE !)@A +, -jk top comp distance to the nipper

If the comb depth is increased by 0.5mm, approximately 2% increase

in noil will occur. When the depth is increased , the main

improvement in quality is seen in Neps. Overdeep penetration of top

comb disturbs fibre movement during piecing which will deteriorate

the quality.

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•LMNO ان\]^ Feed rate

•!)@A +, %rاs Top comp density

Needles of the top comb have a flattened cross section and are used with

a point density in the range of 22 to 32 needles per centimeter. More the

needles, more the noil%.

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در تغذيه مخالف، تعداد دفعاتي كه الياف توسط سيلندر شانه، شانه مي شوند نسبت به

تغذيه موافق بيشتر است لذا جداسازي ضايعات بهتر صورت مي گيرد، هرچند اين

.اختالف در ماشينهاي شانه جديد چشمگير نيست

· With backward feed, top comb penetrates into the fibre fringe which is

already combed by the unicomb, therefore combing action done by top

comb will be better and there will not be longer fibres in the waste

·

· With backward feed, the detaching distance will be less for the same waste

percentage compared to

forward feed. Therefore fibre control during detaching and during top comb

action will be better.

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The type of feed must be adapted

chiefly to the noil%, and/or to the detaching

distance.

Type of feed and detaching distance

Forward feed (V) < 10 mm

Backward feed (R) >8 mm

The type of feed (R or V) in

connection with the

noil% (Y-axis).

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Ratchet wheelFeed amount

per cycle

(mm)

224.3

204.7

185.2

165.9

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+, 1234 t •Comber production

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Production of the comber is dependent upon the following parameters:

N: Nip rate (nips/min)

F: Feed (mm/nip)

W: Batt weight per unit length (g/m)

K: Noil percentage

T: Tension between lap roller and feed roller (from 1.05 to 1.1)

E: Efficiency

P: Comber production (kg/h)

8

480 100

10

N F W E ( K )P

T

× × × × × −=

×

+, 1234 t •Comber production

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Typical performance data of modern cotton combers

Up to 500 nip/minNip rate

Up to 70 kg/hProduction

8Number of combing heads

8-25%Noil extraction

60-80 g/mBatt weight

9-25Draft

3 to 6 ktexSliver weight

4-6 mm/nipFeed rate

650 mmLap diameter (max)

25 kgLap weight (max)

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-uvwx زy 4د Lap Preparation

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A good lap for feeding to the comber should have:

1- highest degree of evenness so that lap is gripped uniformly by

the nipper.

Nipper plate

Nipper knife

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2- good parallel disposition of fibers so that long fibers will not be

lost in the noil.

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· Degree of parallelisation of lap fed to the combers should be optimum. If fibres are over parallelisedlap licking will be a major problem. Because of fibre to fibre adhesion,mutual separation of layers within the sheet is very poor.Moreover the retaining power of the sheet can be strongly reduced that it is no longer able to hold back the neps as it usually does. Some of these neps also pass thro the top comb. Neppiness of the web is increased.

· Retaining power of the fibres results in self cleaning of the lap during combing operation. A thick sheet always exerts a greater retaining power than a thin one.To certain extent, the bite of the nipper is more effective with a higher sheet volume.On the negative side , a thick sheet always applies a strong load to the comb and this can lead to uncontrolled combing.A compromise should be struck between quality and productivity.

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The self cleaning effect of the lap sheet arises from the

retaining power of the fibers relative to the impurities. This

depends on the lap weight. If lap weight is more, the cylinder

comb efficiency may not be good. But the nipper grip will be

good for heavier lap weight. Therefore an optimum lap weight

should be decided. The optimum lap weight in modern

combers can vary between 55 to 75 g/m. It depends on :

• Fiber micronaire (the number of fibers present to the nipper)

• Nipper type

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3- trailing hooks from carding should be fed as leading hooks to

reduce long fiber loss in the noil.

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I II

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Lap preparation

(combing preparation)

Card

Draw

frame

Lap

winder

Comber

1

Card

Lap

winder

Ribbon

Comber

2

چندالكني

بالشچه روبان

بالشچه

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روبان -بالشچه نسبت به روش بالشچه -چندالكنيمزاياي روش

)به علت مكانيزم نسبتا پيچيده ماشين روبان(سادگي باالتر مكانيزم - 1

فضاي اشغالي كمتر - 2

هزينه انرژي كمتر - 3

)امكان تغيير خط به سيستم توليد نخ كارد شده(انعطاف پذيري باالتر - 4

:روبان–بالشچه مزيت روش

يكنواختي عرضي باالتر اليه

بالشچه -مشكل نايكنواختي عرضي اليه تا حدود زيادي در خطوط جديد چندالكنيلذا با توجه به مزاياي فوق الذكر، در صنعت بيشتر از اين روش . برطرف شده است

.جهت آماده سازي بالشچه استفاده مي شود

. پيوند فتيله به جاي پيوند اليه و در نتيجه كاهش عيوب ناشي از پيوند - 5

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• 2-zone drafting system

• 4 calender rollers

•large lap rollers

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• Variable speed

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• Lap spools (empty tubes)

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Doublings max. 28 fold

Input weight max. 140 ktex

Draft 1.36 - 2.2 fold

Batt weight max. 80 g/m

Production speed 70 to max. 140 m/min

Production Up to 350 kg/h

Typical performance data of modern lap winders

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OMEGA technology by Rieter

Combing preparation systems, whether earlier sliver lap/ribbon lap machines or newer draw frame/sliver lap systems – all still employ the lapping method featuring two pressure rollers which drive the lap as it builds up between two discs and create the necessary lapping pressure. In the process the contact pressure acts linearly on the lap surface. Maximum lapping speeds at the start of the lap are 120 to 140 m/min and have to be reduced to as low as 80 m/min as lap diameter increases, depending on staple length, due to the intensive milling action. In order to boost production performance, manufacturers have sought to develop technologies that enable the lap contact pressure to be distributed over a larger surface area. Rieterhave consequently developed and patented a belt lapping system. Instead of the earlier linear load, this enables lap guidance and pressure on the circumference of the lap to be distributed over 180 ° at the start of the lap and 270 ° at the end of the lap. Wrapping with a full lap at the end of the lapping process, resembles the Greek letter Ω .

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1- new tube loading 2- start lap winding

3- lap full 4- lap ejection

Omega - lap winding process

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OMEGAlap E 35 advantages• optimum and gentle fiber control from start to completion of lap• lap forming pressure applied on up to 75 % of lap circumference• no drift - lower CV - constant lap quality• lap winding speed up to 180 m/min• constant winding speed over the entire lap build up process• effective production up to 520 kg/h output• considerably lower power consumption per kg output• the most economical combing set with 1 OMEGAlap and 6 Rieter high production combers.

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For draw frame and lap winder preparation the

total draft can be from 9.5 to 11, depending

upon the fibre and lap weight.

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Lap transport systems

• Fully automated transport system

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• Semi-automated transport system

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• Manual transport system

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