Autoleveller in Drawframe: Types, Operation & Advantages of Autoleveling

Autoleveller

Alternative name for autolevelling include auto regulator, draft, leveller. Although these different names are used by different machinery manufacturers, the basic principle remains the same.

Rieter card leveling operates as medium-term to long-term leveling (closed-loop, produced by a proportional integral regulator) and is performed by a microprocessor. In the feed of the card the feed measuring device records the fluctuations in the cross-section of the batt feed. The speed of the feed roller of the card is changed electronically so that these fluctuations in the cross-section are leveled out. The chute is also included in the control loop.

However, the filling level is not used for regulating the feed rollers in the chute but is considered as an additional control parameter. In the delivery of the card a pair of disc rollers scan the cross-section of the carded sliver as it emerges. These readings are compared electronically with the preselected set value. Deviations in the set value are corrected electronically by altering the speed of the feed roller in the card.

Object of Autoleveling

The object of an autoleveller is to measure the sliver thickness variations and then continuously to after the draft accordingly so that more draft is applied to thick places & less to thin places with the result that the sliver delivered is less irregular than it, otherwise would have been. Besides an improvement in production appearance, autolevelling can also contribute to better productive efficiency, fewer end-breakages in subsequent process, less waste & constant process conditions.

Autoleveller may classified into two main groups according to the basic principle of operation :

• Open loop Autoleveller

The open loop control principle, which can be used for the correction of fairly short term variations, where the solid lines indicate the flow of fibers through the m/c & the broken lines represent to flow of information in the autoleveller unit. The control unit compares the measurement signal with the reference signal which in this case represents the mean output reqd. The control unit accordingly increases, leaves unaltered, or decreases the output of the regulatory which in turn provides a variable speed to the back of front rollers of the process to give the required draft when the measured material  has reached the point at which draft is applied. The magnitude & direction of each change in draft is determined by the magnitude of the change of count previously indicated by the measuring unit. Most of the drawframe autoleveller are open loop auto levellers.

If the direction of the arrows in (a) is followed from any starting point, it always leads out into the open from the diagram at the place marked material by the control unit. Measurement always takes place on the material prior to the material. Thus if measurement is made on the input material, the correction may be applied to either the back rollers or the front rollers.

• Closed loop Autoleveller

The closed loop principle is illustrated in (b); this system is used for the correction of long term & medium term variations. Again the measurement signal is compared with the reference signal by the control unit which then determines the output of the regulator which provides the variable speed to the process to give the required draft.

However, if the direction of the arrows in (b), is following from any starting point except the delivery, is always leads to a never-ending circuit of the loop which links the process & the control unit together, hence the name closed loop; measurement always takes place on the mtl after the point where corrective action is applied. Thus if measurement is made on the output, the correction may be applied to either the back rollers or the front rollers.

It is immediately apparent that the control unit continually cheeks the results of its own actions because measurement is taken from the product of the process. This may be regarded as a basic advantage of the closed loop system, but it is obtained at the price of increased complexity.

Because the flow of fibers in the process forms part of the control loop, this means that the amount of control which can be applied is restricted not only by the limitations of the control unit itself, but the characteristics of the process.

A closed loop system must be designed so as to avoid hunting, i.e. an unwanted oscillation in the output, in this case sliver thickness.

Advantages of Autolevelling

1. All variations are corrected.
2. Count c.v.% will be consistent & good, hence the yarn will be suitable for knitting.
3. Thin places in the sliver, hence in the yarn quality will be low.
4. Ring frame breaks will come down, hence pneumfil waste will be low.
5. Fluff in the department will be less, therefore Uster cuts will be less.
6. Fabric quality will be good because of lower number of fluff in the yarn.
7. Labour productivity will be more.
8. Machine productivity will be more.
9. Idle spindles will be less.
10. RKM c.v.% will be low, because of low number of thin places.
11. Workability in warping & weaving will be good, because of less no. of thin places & lower end breaks in spg & winding.
12. Low sliver U%, hence yarn U% will be good.
13. Production will be more accurate in autoleveller drawframe compared to non autoleveller drawdframe.
14. Variation in Blend percentage will be very less, if both the components are autolevelled before blending, hence fabric appearance after dyeing will be excellent.

PLAIN WEAVE

The plain weave is also known as "Calico" or "Tabby" weaves. This weave is the simplest weave compare to other weaves. Minimum repeat of plain weave is ( 2 x 2 ). This weave have maximum binding points, causes more strength than other weaves. This weaves is use for muslin,blanket, canvas, dhoti, sari, suiting, shirting etc.

METHOD OF CONSTRUCTION

• First, we draw a graph like as ( 2 x 2 ), ( 3 x 3 ), ( 4 x 4 ) etc.
• Second, we show the interlacement as one warp up over the weft, then one weft up over the warp and so on.
• Third, we draw draft by seeing warp up/down in the weave.
• Fourth, we draw peg plan or lifting plan through the help of draft and weave.
• Fifth, we draw denting order.

Plain Weave Construction Method

PLAIN WEAVE DERIVATIVES

The plain weave may be modified by extending warp way or weft way or both ( warp and weft ) way. The extension of plain weave produces a rib effect in fabric. There are three types of plain weave derivatives as following:

• Warp Rib
• Weft Rib
• Matt/Basket/Hopsack

WARP RIB

It is the extension of plain weave in warp direction. That is called WARP RIB. Warp rib is normally used for warp faced construction. The warp rib also classified in two types according to warp up over the weft as follows:

• Regular Warp Rib ( 2/2, 3/3, 4/4, 5/5, 6/6 etc. )
• Irregular Warp Rib ( 2/1, 3/1, 3/2, 4/1, 4/2, 4/3 etc. )

Warp Rib WEFT RIB It is the extension of plain weave in weft direction. That is called WEFT RIB. Warp rib is normally used for weft faced contruction. The weft rib also classified in two types according to weft up over the warp as follows: Regular Weft Rib ( 2/2, 3/3, 4/4, 5/5, 6/6 etc. ) Irregular Weft Rib ( 2/1, 3/1, 3/2, 4/1, 4/2, 4/3 etc. ) Matt Rib Weave It is extension of plain weave in both (warp and weft) direction, that is called matt weave. This weave also known as ‘Basket Weave’ and ‘Hopsack Weave’. The matt weave also classified in four types as following: Regular Matt (3/3, 4/4, 5/5, etc.) Irregular Matt (3/2, 3/4, 4/2, 4/3, etc.) Reversible Matt [(2/3, 3/2), (4/2, 2/4), etc.] Non Reversible Matt [(2/3, 3/1), (4/1, 2/3), etc.]

CLASSIFICATION OF WEAVE

1) Original Weave

          i) Plain Weave

          ii) Twill Weave

2) Derivative Weave

          i) Plain Derivatives

          ii) Twill Derivatives

CLASSIFICATION OF PLAIN DERIVATIVES

•      Rib

a)   Warp Rib

          i) Regular

              ii) Irregular

b)   Weft Rib

          i) Regular

              ii) Irregular

• Matt/Basket/Hopsack

a)   Regular

b)   Irregular

c)   Reversible

d)   Non-Reversible

WARP RIB

It is the extension of plain weave in warp direction. That is called WARP RIB.

WEFT RIB

It is the extension of plain weave in weft direction. That is called WEFT RIB.

MATT

It is the extension of plain weave in both warp and weft direction. That is called MATT.

FABRIC STRUCTURE AND ANALYSIS MODEL PAPER DEC-2019

Question 1(a) Primary weaves with design.

Primary Weaves:

Weave is design, which is incorporated on loom machine by the interlacement of warp and weft, and the process of interlacement is called weaving. There are three types of primary weaves:

1. Plain Weave
2. Twill Weave
3. Satin Weave

Question 1(b) Ways of ornamenting plain fabric.

Ways of ornamentation of plain fabric:

Various types of plain weave are commonly used in the market. They are different in outlook, they are made by same design but outlook changed by using ornamentation technique. Some ornamentation techniques are as below:

• By using fine count yarn.
• By using coarse count yarn.
• By using different colours thread.
• By using thread on warp and weft may be different-different colours and count.
• By using fancy slub yarns.
• By using different twisted yarn.
• By using different textile material.
  

Question 1(c) Crepe weaves and their construction.

Crepe Weave And Their Construction:

In crepe weave consists an useful variety of simple weaves. Due to their pebbly or rough surface, crepe weaves also known as “Crape” or “Oatmeal” fabrics. Highly twisted yarn (crepe yarn) or crepe weave used for producing crepe effect on fabric. Crepe weave used with other elementary weaves. There are 4 types of crepe weaves:

1. Crepe with sateen weave.
2. Crepe with another weave.
3. Combination of plain weave.
4. Crepe by reversing method.

1. Crepe with sateen weave:

In this weave (Crepe with sateen weave), we draw a basic sateen weave and after shown warp up over the weft or weft up over the warp. Weave and their method of construction are as following: 

Method of construction:

• We draw an area (5x5).
• We choose a move nos. 3.
• We choose 3 warp up and 2 weft up.
• We fill basic sateen weave by using move nos.3.
• We shown 3 warp up and 2 weft up.
• We draw draft by using warp working of weave.
• We draw peg plan by using draft and weave.

Question 2(a) Make one repeat of Huck-a back.

Huck-a-back weave:

Huck-A-Back weaves are basically toweling weaves. They are constructed by alternatively combining a float with plain weave. This weaves are suitable for producing heavy textures. This weave have two parts, first is plain weave, which provides more strength to the fabrics and second is long float, which provide more moisture absorbency to the fabric. This weave is use cotton and linen fabric, towel and glass cloth.

Method of construction:

Question 2(b) Make one repeat of Honeycomb.

Honeycomb weave:

The honeycomb terms used for these weaves, which are partial resemblance honeycomb cells of bees. These weaves produce ridges and hollows on texture. Warp and weft threads produce a floats bothside of fabric, which gives moisture absorbent property to the fabric. There are two types of honeycomb weave:

1. Ordinary/Simple Honeycomb Weave
2. Brighton Honeycomb Weave

Simple Honeycomb Weave

In this weave ( Simple Honeycomb Weave ), we draw two diagonal lines across one-another and after draw a motiff, which id divided in two parts. Weave and their method of construction are as following:

Method of construction:

• We draw an area (10x10).
• We draw a diagonal line shown d.green.
• We draw 2^nd diagonal line shown light green.
• We fill one motif (half upper side and half lower side) leaving 1 stitching point shown white colour.
• We draw draft by using warp working of weave.
• We draw peg plan by using draft and weave.

Question 2(c) Make one repeat of Mockleno.

Mockleno weave:

Mock leno also known as imitation lenos. Mock leno are a variety of weaves of ordinary construction, which produce effects that similar in appearance to the gauze or leno styles obtained with the help of doup mounting. These weaves are generally produced in combination with plain, twill, satin or other simple.

Use: Canvas clothes, curtains, light dress fabrics, blouses aprons etc.

Method of construction:

• We draw an area (8x8).
• We divide the area into 4 parts.
• We fill the motiff in 1^st and 3^rd part.
• We fill the reverse weave of 1^st and 2^nd part in 3rd^nd and 4^th part.
• We draw draft by using warp working of weave.
• We draw peg plan by using draft and weave.

Q3(a) Describe Pointed Twill Weaves.

Q3(b) Describe Herringbone Twill Weaves.

Q3(c) Describe Broken Twill Weaves.

Question 4(a) Draft and their types.

Draft:

Draft indicates the number of healds used to produce the design (weave). It shown which heald is up at the time of pick insertion.

Types of draft: The various types of draft as following:

1. Straight Draft
2. Pointed Draft
3. Broken Draft
4. Curved Draft

Straight Draft:

This is the most commonly used draft. It is the simplest draft of all types of draft plans. In this draft the drafting order progresses successively from first to last heald frame.

Pointed Draft:

This is similar to straight draft. It is suitable for weaves such as pointed twill, diamond weaves and ordinary types of honeycomb weaves.

Broken Draft:

A broken draft almost resembles the pointed draft. However the pointed effect is broken. This type of draft is suitable for herringbone twill weaves.

Question 4(b) Determination of warp and weft.

Any woven fabric produce by interlacement of two types of yarn known as warp yarn and weft yarn.

Plain Weave Derivatives:

The plain weave may be modified by extending warp way or weft way or both (warp and weft) way. The extension of plain weave produces a rib effect in fabric. There are three types of plain weave derivatives as following:

1. Warp Rib
2. Weft Rib
3. Matt/Basket/Hopsack

Warp Rib: It is extension of plain weave in warp direction, that is called warp rib. Warp rib is normally used for warp faced construction. The warp rib also classified in two types according to warp up over the weft as following:

• Regular Warp Rib (2/2, 3/3, 4/4, 5/5 etc.)
• Irregular Warp Rib (2/1,3/1, 3/2, 4/1 etc.)

Weft Rib: It is extension of plain weave in weft direction, that is called weft rib. Weft rib is normally used for weft faced construction. The weft rib also classified in two types according to weft up over the warp as following:

• Regular Weft Rib (2/2, 3/3, 4/4, 5/5 etc.)

• Irregular Weft Rib (2/1,3/1, 3/2, 4/1 etc.)

Matt Weave: It is extension of plain weave in both (warp and weft) direction, that is called matt weave. This weave also known as ‘Basket Weave’ and ‘Hopsack Weave’. The matt weave also classified in four types as following:

• Regular Matt

• Irregular Matt

• Reversible Matt

• Non- Reversible Matt

Question 5(a) Design and its repeat.

Design: Design is the disposition of lines. The design indicates the interlacement of warp and weft threads in the repeat of the design. Those design, which is applied on textile material through printing, interlacement, knitting etc., that is called Textile design.

Question 5(b) Formula for calculating weight of fabric.

GSM: GSM stands for " Grams per Square Metre ". Generally we use GSM cutter for cheking GSM of any fabric. we also calculate GSM of woven fabric by using formula as below:

Question 5(c) Fabric analysis particulars.

Fabric analysis particulars: The fabric analysis particular are as following:

1. Minimum Repeat
2. Weave
3. Draft
4. Peg Plan
5. Denting Order

Minimum Repeat: Minimum repeat is a minimum area, in which a complete design can be shown. For example plain weave minimum area is (2x2), twill weave minimum area is (3x3) etc.

Weave: Weave is a design, which is incorporated on loom machine by interlacement of warp and weft. This process is called Weaving.

Draft: Draft indicates the number of healds to be used to produce a design.

Peg Plan: It shows the selection of healds to be raised or lowered at each insertion of picks.

Denting Order: Denting order is the number of ends pass through a dent of reed. There are two to five ends pass through a dent of reed.

COMBINE TWILL WEAVE

Method Of Construction

CREPE WEAVE

In crepe weave consists an useful variety of simple weaves. Due to their pebbly and rough surfaces, crepe weave also known as "Crape" or "Oatmeal" fabrics. Highly twisted yarns ( crepe yarns ) or crepe weave used for producing crepe effects on fabrics. Crepe weave used with other elementary weaves.

Crepe Weave

Crepe Weave

Crepe Weave

Method Of Construction

• First, we draw an minimum area such as ( 5 x 5 ).
• Second, we fill sateen weave with move nos. 3.
• Third, we show 3/2 on each warp yarn.
• Fourth, we draw an area for draft and fill it according to warp working in weave.
• Fifth, we draw an area for peg-plan and fill it according to weave and draft plan.

2. Crepe With Another Weave

Method Of Construction

Method Of Construction

• First, we draw two sateen weave area such as ( 7 x 7 ) with different-different move number.
• Second, we draw a minimum repeat area ( 7 x 7 ).
• Third, we fill both sateen weave one-by-one.
• Fourth, we draw an area for draft and fill it according to warp working in weave.
• Fifth, we draw an area for peg-plan and fill it according to weave and draft plan.

3. Combination Of Plain Weave

Method Of Construction

TWILL WEAVE

The basic features of twill weave are as below:

• They form diagonal lines.
• More ends per unit area and more picks per unit area comparatively plain weave.
• Less binding points comparatively plain weave.
• More cloth thickness and mass per unit area.

Classification Of Twill Weave

2. Pointed Twill Weave

Pointed twill weave also known as Zig-Zag twill weave. In this weave, the direction of twill lines changes alternatively. For example one from left to right and then right to left and so on.

Types Of Pointed Twill Weave

• Regular Pointed Twill Weave
• Irregular Pointed Twill Weave

Minimum Repeat of Regular pointed twill weave is ( 4 x 3 ) and irregular pointed twill weave is ( 6 x 3 ).

Condition Of Pointed Twill Weave

The condition of pointed twill weave is that it always finish on second pick.

e/p ≠ whole number for regular pointed.( 4 x 3 )

e/p = whole number for irregular pointed.( 6 x 3 )

Condition Of Pointed Twill Weave