Draw frame

Drawframe is one of the important machines in yarn spinning line. It is prepared for combining and drawing slivers and removing card irregularities of textile fibres.

1. BASIC INTRODUCTION ON DRAWFRAME

2. Introduction: Drawframe is a machine in spinning line which comes after blowroom and carding machine. The main operation which is followed by drawframe is Drawing by which slivers are blended, doubled and levelled. Drawframe is the definitive compensation point for eliminating errors. High performance drawframes currently produce over 400 kg of sliver per hour at each delivery.

3. Objectives of Drawframe: Equalizing : One of the main tasks of drawframe is improving evenness of the sliver by drafting and doubling . Parallelizing: To straighten the fibers and to make them parallel to the central axis for obtaining an optimum value of yarn strength. Every drafting step leads to straightening and parallelizing of the fibers for better orientation. Blending: To blend raw materials of same hank perfectly . Dust removal: With removing irregularities from carded slivers, It also removes dusts from slivers. Hook Removal: The card sliver contains more trailing hooks than leading hooks. In drawframe, Trailing hooks are removed and leading hooks are present in feed sliver.

4. Images of Drawframe. CONVENTIONAL DRAWFRAME MODERN DRAWFRAME

5. Main Parts of Drawframe Drawframe consists of four sections: Creel Section Drafting Section Sliver condensing section Coiler Section

6. Operating Principle Sliver fed:6 – 8 Draft: 5 – 8 Drawn sliver can capacity: 15-22 kg No. of heads: Single/double Delivery Rate: 350-800 m/min ( Generally,Two production heads are common and Sliver may be fed in from up to 8 cans per drawing head)

7. The Drafting Arrangement Elements of Drafting arrangement- Bottom Rollers : -made of steel (metal) -mounted in roller strands/frame by means of needles, rollers or ball bearings. -positively driven from the main gear transmission. -formed with flutes to improve the ability of carrying fibers along. Top Rollers : -made of steel and covered with thick coating of synthetic rubber. -not positively driven. -Soft rubbers coating can grip the fibre strand more perfectly than that of hard one, but soft one wears out more quickly. Top roller pressure : To clamp the fibers , the top rollers must be forced at high pressure towards the bottom roller. The pressure can be generated by dead weights, spring weighing e.t.c .

8. The reduction of weight/yard of sliver and increase in length is called drafting . Or Attenuation of sliver without breaking is called draft . If we consider a 3-over-3 roller drafting arrangement,then - The zone between back rollers and middle rollers is known as ‘Break Draft zone ’. The zone between middle rollers and front/delivery rollers is known as ‘Main Draft zone ’. The Draft between the back rollers and middle rollers is known as Break draft (usually 1.25-1.8) and the draft between middle rollers and delivery rollers is known as Main draft. V 1 ,V 2 ,V 3 a re the surface speeds of back, middle and front rollers and V 1 <V 2 <V 3 . Here the rollers diameters are same so delivery roller speed(rpm) Draft = feed roller speed(rpm ) , thus, Break draft= V 2 /V 1 ,Main draft = V 3 /V 2 Total Draft of 3-over-3 drafting system = Break draft * main draft = V 3 /V 1 Drafting Operation

9. Influences on the Draft Factors dependent upon the fiber materials- mass of the fibers in the strand cross section. degree of order of the fiber . length of the fiber . compactness of the fiber strand. twists present in fibre strand etc. Factors dependent upon the drafting arrangement- diameters of the rollers. hardness of the top rollers. pressure exerted by top rollers. clamping distance. level of the draft. type and forms of fiber guiding devices such as, pressure nods, pin bars, condensers etc.

10. What is Drafting force? It is the force required to accelerate a bunch of fibers.Due to acceleration of the fibers , attenuation is carried out from slower speed (back roller) to greater speed(front roller). It is heavily dependent upon : Fibre length Arrangement of fibres in the cross section ( parallel or crossed) Cohesion between fibers Nip setting Area of overlapping region (higher the area, more force is needed) What is Ideal Drafting? It is defined that the fibers should move with the speed of the back roller until and unless it is gripped by the front roller nip.

11. Doubling In a drafting system 6 or 8 slivers are fed together which is known as number of doubling . So, if 8 slivers are fed to the drafting system, then the number of doubling is 8. In Drawframe , the no. of doubling and the total draft is almost equal. As per requirement of sliver delivered, practically total draft is lesser or higher than no. Of doubling. If our requirement is to get coarser sliver, here draft is reduced and the value of draft is lesser than the no. of doubling. If our requirement is to get finer sliver, here draft is increased in such a manner that the value of draft will be greater than the no. of doubling. So, in practice the total draft may be greater or equal to the no. Of doubling.

12. Law of Doubling It is expected that the thick places of one sliver will be compensated by the thin places of neighbouring sliver or vice-versa. So, the irregularity of delivered sliver is less than the irregularity of feed sliver. If, CV i is the co-efficient of variation of input sliver, CV o is the co-efficient of variation of output sliver and n is the no. of sliver fed( no of doubling),then- CV o = CV i / √n [ here added irregularities is considered as 0]

13. Types of Drawframes - Breaker Drawframe - Finisher Drawframe Generally two drawframes are used in industries in random. The First drawframe is known as ‘Breaker Drawframe ’. It removes the card sliver irregularities. The second drawframe is known as ‘Finisher Drawframe ’. It removes the drawn sliver irregularities. Problems of using higher no. of drawframes - Power and labour consumption Space requirement High initial investment

14. Role of Autoleveller in Drawframe Autoleveller is an additional device which is meant for correcting the linear density variations in the delivered sliver by changing either the main draft or break draft of the drafting system, according to the feed variation. It maintains the consistent hank of sliver or count C.V% , hence the yarn will be suitable for dyeing evenly and knitting.

15. Types of Autoleveller There are two types of Autolevelling systems. They are- -Open loop system -closed loop system Most of the autolevellers which are incorporated in the Finisher Drawrframe are open loop auto levellers . In open loop autolevellers , sensing is done at the feeding end and the correction is done by changing either a break draft or main draft of the drafting system. In closed loop system sensing is done at delivery side.

16. Delivery: Condensing and Coiling Condensing:- Delivery roller  converging tube(1 )  trumpet guide (2) calender roll (passes the fiber (collects them)(condensing) (compressing and web to 1) depositing to coiler) Coiling: Calender rollers  Coiler tube (fixed on  Cans (rests on rotating plates) (passes drawn sliver)  the coiler plates ) (coiler gears fixed on coiler plates, helps to rotate the coiler tube so the sliver can be laid in the cans in forms of coils)

17. Features of Modern Drawframe Automatic Can Changer: For the efficiency the modern drawframe is equipped with two completely independent automatic liner can changers. The empty can magazine contains two cans per side. The cans are transported through the machine from the rear to the front. Efficient Suction system: Additional succession position in the sliver feed i.e before scanning of the autolevelling ensures optional sliver purity and less cleaning already at the beginning of the drafting process.

18. PRESENTED BY- NAME: SUBARNA DEY STREAM: TEXTILE TECHNOLOGY ROLL: 11101417009 SUBJECT: YARN FORMATION III ( TT-601) YEAR: 3 rd YEAR SEMESTER: 6 th SEMESTER

19. THANK YOU