Ring spinning machine:
This ring spinning was much more productive, simpler in mechanism, easier in manipulation and more economic. This was the origin of ring twisting, probably the most extensively used system for the processes of simultaneously twisting yarn and winding it onto a package.
Functions of ring frame:
- To draft the roving for conversion of very fine strand of some fiber to form yarn of required count.
- To impart strength to the yarn by inserting the necessary amount of twist.
- To collect twisted strand called yarn onto handy and transportable.
Main advantageous features of ring spinning machine:
- Most usable spinning machine in the world.
- Fine to coarse (5-1000 tex) yarn can be produced.
- Yarn has very good strength.
- Yarn is suitable for all next process.
- More than 80% of total yarn is produced by ring spinning machine.
Limitations of ring spinning:
- Low twisting rate
- Low production
- Small bobbin size
- Frequent doffing
- High energy consumption
- Limited speed of traveller.
Drafting system makes important role at yarn quality and performance of the machine. Normally 3 over 3 drafting system is used at ring frame. Total draft, draft distribution and arrangement of drafting system is very important both for yarn quality and machine performance. Total draft, break draft and distribution of draft for different yarn are given below:
Total draft = Break draft or break zone draft X Front zone draft
- Bottom rollers are fluted steel roller.
- Top rollers are rubber roller, which are pivoted at weighting arm can apply pressure 15-25 daN to the bottom roller.
- Apron is a endless synthetic rubber small belt, which guide the drafted fiber.
- Hardness level of top back roller 80°- 85° shore and 63°- 65° shore at top front roller.
Method of applying pressure:
The following way load or weighting is applied at the nip point of bottom roller by top roller.
- Spring loaded
- Pneumatic weighting
- Magnetic weighting
Different parts of ring spinning machine:
- Roving bobbin
- Bobbin holder
- Guide roller
- Drafting arrangement
- Bobbin tube
- Ring rail
A brief description of important parts of ring spinning machine:
Spindle is a hollow cylindrical tube, consists of mainly two parts (upper parts bolster) and capable to run high speed. Normally upper part of spindle is taper, which holds ring cop and bolster is fixed to the ring rail by nut. Spindle is driven by tape at the position of whorl. The diameter of whorl is important for high speed.
Lappet consists of thread guide and an arm. This thread guide lead the yarn centrally over the spindle axis and arm fix at lappet rail.
Ballon control ring:
Ballon control ring is a ring, which control or reduces the diameter of yarn ballon at middle position. Actually it divided the ballon into two sub-ballons. Normally yarn ballon is formed during twisting and winding of yarn at ring spinning machine.
Separator is an aluminum or plastic plate, which is placed between the individual spindle to prevent the hurled of broken thread to neighboring yarn making ballon.
This is the renowned ring, so for the frame is named as ring spinning frame. Most commonly carbon steel is used; but different hardened steel is also used. The ring is tough and hard. The range of its surface hardness is between 800-850 vickers. Ring diameter varies 38-54 mm.
Feature of a good ring:
- Exact roundness.
- Best quality raw material.
- Good, but not too high, surface smoothness.
- An even surface.
- Good, even surface hardness, higher than that of the traveller.
- Long operating life.
- Correct relationship between ring and bobbin tube diameters.
- Perfectly horizontal position.
- It should be placed exactly centered relative to the spindle.
This is the tiny key parts of ring spinning frame which travels around the ring at 30-35 m/sec and impart twist to the yarn. The hardness of the running traveler must be within 650-700 vickers. Contact pressure between ring and traveler is up to 35N/mm². Generate high temperature (300-400°C). the mass of traveller is 16-120gm/1000
Feature of a traveller:
- Generate less heat.
- Dissipate heat fastly.
- Have sufficient elasticity for easy insertion and to retain its original shape after insertion.
- Friction between ring and traveller should be minimal.
- It should have excellent wear resistance for longer life.
- Hardness of the traveller should be less than the ring.
Forces acts on ring-traveller:
Yarn is wound around ring cop by cop building mechanism. There are approximately 100-200 gm yarn present in every ring cop.
- Spindle per machine = 480 -1016
- Spindle speed = 12,000 – 20, 000 rpm
- Draft = 15- 45
- Yarn count = 1- 120 Ne
- Production (machine/hr) = 22-30 kg
- Ring cop weight = 180 – 250gm
Winding and heat setting:
Winding is the process of transferring yarns from small ring cop to a suitable large package. Yarn faults like thick and thin places, neps, slubs, and foreign materials are removed here by EYC (Electronic yarn cleaner), which increase the quality of yarn. Store and transfer of yarn is easier for package size. 12-18 ring cop are used to build a winding package (cone).
Heat setting or twist setting:
Newly manufactured yarn has low moisture content and it has snarling tendency. Heat setting is a process, by which yarn receives sufficient moisture, twist sets in certain place and reduces snarling tendency. Heat setting is done by steam with temperature of 60°c during 50-60 minute with a pressure of 5 kg/cm². At a time 200-300 packages insert in a heat setting chamber for this purposes. Some yarns are heat set by waxing with wax devices; these are used only for knitted fabric manufacturing.
Yarn cones are packed in paper cartoons 50 kg for export and 45 kg for local market. Yarn hanks (1lb) are packed 50 kg in sacking for local market for hank dyeing.
Draft and production of ring spinning mill (section wise):
Production heads/ machine
600 – 1200
80 – 120
0.1 – 0.15 Ne
1 or 2
5 – 10
100 – 300
0.12 – 0.18 Ne
1 or 2
5 – 10
10 – 30
0.12 – 0.2 Ne
5 – 15
70 – 130
0.7 – 1.8 Ne
496 – 516 or
15 – 50
10 – 14
Yarn in cop
1 – 120 Ne
40 – 60
70 – 120
Yarn in cone (2 kg) or hank
Same as ring
Same as ring
Name of various spinning method:
Flyer –spinning machine
Air jet spinning
Cap – spinning machine
Air vortex spinning
Centrifugal – spinning machine
Pot – spinning machine
Self- twist spinning
Image courtesy: http://nptel.ac.in
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