Classification of drafting system in the ring frame | Explanation of a modern system

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 –

1. Conventional three roller system.
2. Improved system.
3. H and B four rollers long draft system.
4. 5 over 4 roller systems.

Example of single apron drafting system –

1. Saco – Lowell. Both systems.
2. Saco – Lowell. Shaw system.
3. Saco – Lowell. Z system.
4. Toenniessen system. and
5. Versatex LS system.

Example of double apron drafting system –

1. Casablancas double apron system.
2. Casablancas “L” system with flexible bar.
3. Saco – Lowell thread rollers duo-Roth system.
4. SKF pendulum top arm weighting system. And
5. Saco – Lowell 4 – roller Duo – Roth system.

Example of multiple Apron drafting system –

1. Casablancas “N” system.
2. Nittoh’s Semi-super high draft system.
3. OM – S super high draft system.

OM – Super high draft system –

This system is specially designed to spin direct from drawing sliver using special size small sliver cans in place of usual roving bobbin in the creels as shown in the figure below fig. –

The back draft zone is in vertical position and the front zone is inclined position to 50⁰. The rollers are spring weighted. In this system the back draft zone is equivalent to the draft of a sliver and the drafting arrangement resembles to that of the long draft sliver (Back, 4^th and 3^rd rollers). The front zone (3^rd, 2^nd, and front roller) resembles the ordinary Casablancas system.

It is claimed that, draft from 300 – 400 for count of 60^s – 80^s and 150 – 250 for count 20^s – 40^s can be obtained.

What are the functions of Ring, Traveller, Creel, Spindle, Roving guide and Lappet motion?

Ring – 
The functions of ring are –

1. The ring guides the circular run of the traveller.
2. The ring act as a high speed bearing surface for the travellers.
3. One may also conceive the behavior of the ring as a track for the traveller.

Traveller –

It performs the following functions –

1. Twisting of the drafted strand of fibres as they are delivered by the front roller to produce a yarn.
2. Winding of yarn onto the bobbin.
3. Maintain winding tension of the yarn by the frictional resistance between the ring and traveller.
4. It acts as a second guide for the yarn on the way to be wound on the bobbin.
5. It performs the function of building motion to wind the constant length of yarn delivered by the front roller. In speed frame bobbin r.p.m changes with the increase of bobbin diameter but in ring frame the bobbin r.p.m remains constant and the traveller r.p.m increases with the increase of bobbin diameter.

It also performs many other functions involving highly complicated problems of higher physics.

Creel –

The function of the creel is to hold the roving bobbin over a roller beam within a convenient height to easily handle the roving. The creel must permit free running of the roving bobbins with slight tension on it.

Spindle –

1. The spindle holds the bobbin somewhat loosely but tight enough to prevent any slippage, so that the bobbin can be lifted out of the spindle with little exertion.
2. With the help of the ring and traveller the spindle inserts twist in the yarn being delivered by the front roller.
3. It also carries out another important function of winding the twisted thread on the bobbin with the help of ring and traveller.

Roving guide –

The guides are mounted at the right angle to the flat bar called traverse bar. The object of the guide is to feed the roving correctly at the bite of the back roller and the traverse motion moves the strand almost over the entire length of the bite and this prevents the drafting rolls from being grooved at a particular place.

Lappet motion or thread board traverse –

The main function of the thread board traverse is to maintain the balloon size within the controlling range. To keep the balloon length within the controlling limit, the thread board is necessarily be made to traverse relative to the ring rail. For 8” lift bobbin the traverse of the ring rail is more or less confined within the range from 1” – 1.5” and higher traverse for higher lift of the machine.

The slow traverse of lappet-rail also facilitates the easy passage of the yarn from the front roller to the bobbin.

Definition, objects and process layout of Blow room

Blow room|Objects|Basic operations|Actions|Process layout of yarn manufacturing with a modern blow room line 

Blow room: The section where the supplied compressed cotton bale turns into a uniform lap of particular length by opening, cleaning, blending or, mixing is called blow room section. It is the first step of spinning. The section consist a number of different machines used in succession to open and clean the fibres.

Objects of blow room:

• Opening- Opening of compressed cotton bales and cotton bales are made into small tufts.
• Cleaning- To eliminate dust, dirt, broken leaf, seed particles, grass and other foreign impurities from the fibre.
• Blending/mixing- To produce a comparatively good quality cotton fibre by mixing different types of cotton together.
• Lap forming–

(a) To convert the opened and cleaned fibre into a sheet of particular width and uniform weight/unit length is called lap.

(b) To give a cylindrical shape to the pre determined lap by winding it in the lap pin and to make it suitable for the next process carding.

Basic operations involved in the blow room:

• Opening- Opening is the first operation in the blow room carried out to the stage of flocks in the blow room and to the stage of individual fibres in the cards.
• Cleaning- To remove the impurities, foreign materials and the raw materials as clean as possible.
• Dust removal- To remove the dusts which are completely enclosed in the flocks.
• Blending- To achieve the required quality of yarn by blending different kinds of cotton into a particular ratio.
• Even feed of the material- To produce a lap of uniform weight per unit length or, to process the maximum quality which is suitable for carding.

Actions of blow room:

(a)   Action of opposite spike(Opening)

(b)  Action of air current(Transport Cleaning)

(c)  Action of beater and grid bar(Cleaning and opening)

(d) Action of regulating motion(Uniform output)

Process layout of yarn manufacturing system with a modern blow room line:

Bale plucker

↓

Metal detector

↓

Uniclean

↓

Unimix

↓

Uniflex

↓

Vision shield

↓

Condenser

↓

Chute feed

↓

Carding

  ↓

↔

↓                                                            ↓

For carded yarn                                     For combed yarn

↓                                                               ↓

Breaker drawing                                    Pre-comb drawing

↓                                                                ↓

Finisher drawing                                    Lap former

↓                                                                ↓

Simplex/Roving/Speed frame            Comber

↓                                                               ↓

Ring frame                                              Post-comb drawing/Finisher drawing

↓                                                               ↓

Auto coner                                          Simplex/Roving/Speed frame

↓                                                               ↓

Heat setting                                              Ring frame

↓                                                                ↓

Packing                                                    Auto coner

↓

Heat setting

↓

Packing