Different types of Drafting Arrangements which is used in Spinning Mill.

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1. Welcome To Our Presentation Yarn Manufacturing-II (TE312)

2. Our Topic Study on Different types of drafting arrangement which is used in Spinning Mill Name: Niloy Saha ID: 162-23-4732 Sec: B (Eve) Name: Mehedi Hasan ID: 162-23-4731 Sec: B (Eve)

3. What is Drafting ? Drafting is the creation of a drawing or other graphical representation of a building, mechanical device or other structure for the purposes of determining how the device should be created. Drafting is used as a part of the design and fabrication processes. Drafting can be done by hand or using specially designed computer programs and mechanical drawings . Drafting arrangement is the most important part of the machine. It influences mainly evenness and strength The following points are therefore very important drafting type design of drafting system drafting settings selection of drafting elements like cots, apron, traveler etc. choice of appropriate draft service and maintenance

4. Types of Drafting System: There are commonly two types of drafting system are used in ring frame: Spring loaded drafting system or pendulum arm. example: SKF PK 2025 or Texparts 2035 Pneumatic drafting system: SKF PK 3025

5. SPRING-LOADED PRESSURE ARM (TEXPARTS PK 225, FOR EXAMPLE) Each compensating roller is seated in a bearing slide ( 1 ,  2 ,  3 ); these are infinitely adjustable relative to each other. A spring ( 4 , 5 ,  6 ) – sometimes two on the front roller – presses the top roller against the bottom roller. In the case of SKF the loading pressure can simply be adjusted in three stages by means of a tool. Colored marks indicated the set loading stage. Fig . – SKF PK 225 rocking support

6. PRESSURE ARM WITH PNEUMATIC LOADING (RIETER FS 160 P 3.1, FOR EXAMPLE) The loading support is stamped from steel sheet and is mounted on a continuous hexagonal section tube behind the rollers. The tube contains the compressed air hose connected to a central compressor unit. Three top roller holders mounted on two bearing slides are accommodated in the loading support itself. The two bearing slides form a double lever system. Depending on where a pin is inserted in one of the three holes as the pivot at „ m “, the total pressure coming from the compressed air hose and acting on the entire pressure arm via a cam is applied more strongly to the back roller or the two front rollers. Pressure can also be distributed differently between the two front rollers via a second pin/hole system in the bearing slide of these two rollers at „ n “. Fig. 13 – Pneumatic loading by Rieter

7. Classify the drafting systems used at the ring frame with example and explain a modern system Drafting system can be broadly classified under two heads namely – 1. Regular drafting system without apron. And 2. Drafting system with apron. The system with apron can again be classified into three groups – 1. Single apron system. 2. Double apron system. and 3. Multiple apron system. Example of regular drafting system without apron – a. Conventional three roller system. b. Improved system. c. H and B four rollers long draft system. d. 5 over 4 roller systems. Example of single apron drafting system – a. Saco – Lowell. Both systems. b. Saco – Lowell. Shaw system. c. Saco – Lowell. Z system . d. Versatex LS system. Example of double apron drafting system – a. Casablancas double apron system. b. Casablancas “L” system with flexible bar. c. Saco – Lowell thread rollers duo-Roth system. d. SKF pendulum top arm weighting system. And Example of multiple Apron drafting system – a. Casablancas “N” system. b. Nittoh’s Semi-super high draft system. c. OM – S super high draft system.

8. Roller drafting system: Commercially , there are various methods to draft the textile fibrous material like roller drafting system applied at ring spinning, speed frame and draw frames etc , aero dynamic drafting functional at rotor spinning, electro mechanical drafting, frictional drafting, etc. Out of these techniques, roller drafting system is the most commercially successful one due to its high versatility, simple design and construction, high reliability and can handle variety of fibres and a wide spectrum of count range can be spun. Fig : 3/3 roller drafting system at ring spinning

9. THE DRAFTING ARRANGEMENT In the Rieter comber, the sliver table leads to a vertically inclined 3-over-3 drafting arrangement (Fig. 56), sometimes with an additional pressure bar in the main draft zone. The rollers form two drafting zones. Break draft as well as main draft distances and the amounts of draft are variable. The overall draft lies between 9 and 16. At the delivery end of the drafting arrangement a trumpet collects the discharged web and guides it, with additional compacting, to the delivery rollers. Fig. 56 – The drafting arrangement of the Rieter combers Fig. – Sketch of the drafting arrangement of the Rieter E 65/75 combers

10. DOUBLE APRON DRAFTING SYSTEM WITH LONG BOTTOM APRON In the double apron drafting system the fiber guidance unit consists of two aprons rotating with the middle rollers. The top apron must be pressed against the bottom apron with controlled force in order to provide guidance. For this purpose there must be a gap between the two aprons at the apron delivery end (tensor gap) that is precisely adjusted to the fiber volume. This gap can be adjusted by using different spacer plates, shoes, etc. Fig . – Long bottom apron

11. DRAFTING FORCE The effective drafting force can be represented by the curve form shown in Fig. 45. Up to point m, at which the fibers begin to slide apart, the curve climbs steeply. This is the straightening and extending stage. From point n onwards, by which stage many fibers are already sliding, the curve falls slowly with increasing draft. The reduction of the drafting force with the increasing extent of draft is easy to explain – there is a continuously declining number of fibers to be accelerated, i.e. to be drawn out of the slowly moving strand, since a higher degree of draft implies fewer fibers in the cross-section. Fig .– The forces acting on fiber (f) during drafting Fig. 45 – Drafting force diagram; F, magnitude of the drafting force. D, magnitude of the draft

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