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Rotor Spinning internship report - Vinod spinners, Ahmedabad

Rotor Spinning internship report

Table of Contents

Chapter 1 Company Overview

Chapter 2 Overview of the Spinning department in the company
2.1 - 2.5 - Link
2.6 Rotor Spinning Machine 
2.6.1. Rotor Spinning Principle 
2.6.2. Passage and working parts of Rotor Spinning Machine

Chapter 3 Introduction to Internship

3.1 Objective of Mill Training.

Chapter 4 Testing
4.1. HVI instrument 
4.2. Premier IQ2 (Evenness tester) 
4.3. Wrap Reel
4.4. C.S.P. Yarn Strength machine

Rotor Spinning internship report

2.6 Rotor spinning machine

The Vinod Spinners Plant works entirely on open-end spinning technology spinning.

Schlafhorst SAURER AUTOCORO spinning machine. No. of Machines installed - 4 (552 Spindle Per Machine) Model Of Machine: - 2 Machine are Acco8

2 Machines are Acco9. Twist produced: Z twist only.

Automatic piecing: Coromat automatic splicer Count Range: 5.0 to 24 count.

The yarn formed is rolled in form of cheese, cone and bobbin.
The speed of the rotor roll varies from 60,000 rpm to 1, 40,000 rpm.

Rotor spinning machine

Open End spinning:

  • Rotor Spinning is a more recent method of yarn formation compared to Ring Spinning.
  • This is a form of open-end spinning where a twist is introduced into the yarn without the need for package rotation. Allowing higher twisting speeds with a relatively low power cost.
  • In rotor spinning a continuous supply of fibres is delivered from delivery rollers off a drafting system or from an opening unit.
  • The fibres are sucked down a delivery tube and deposited in the groove of the rotor as a continuous ring of fibre. The fibre layer is stripped off the rotor groove and the resultant yarn is wound onto a package.
  • The twist in the yarn is determined by the ratio of the rotational speed of the rotor and the linear speed of the yarn.
  • Sliver is fed into the machine and combed and individualized by the opening roller.
  • The fibres are then deposited into the rotor where air current and centrifugal force deposit them along the groove of the rotor where they are evenly distributed.
  • The fibres are twisted together by the spinning action of the rotor, and the yarn is continuously drawn from the centre of the rotor. The resultant yarn is cleared of any defects and wound onto packages.
  • The production rates of rotor spinning are 6-8 times higher than that of ring spinning and as the machines are fed directly by sliver and yarn is wound onto packages ready for use in fabric formation the yarn is a lot cheaper to produce.
  • Rotor-spun yarns are more even, somewhat weaker and have a harsher feel than ring-spun yarns.
  • Rotor-spun yarns are mainly produced in the medium count (24 Ne) to coarse count (5.0 open-ended.
  • The yarn is wound on a fibre package of about 3.5 to 4 kg.
  • Thopen-end this system has two basic advantages. It fibres by sliver, not as with the intwists roving, and so eliminates the speefibrese from the process line. It can also be modified to remove any remaining trash, thereby improving the yarn quality. 



Rotor spinning is the most widespread system in the open-end yarn manufacturing industry. It has all the necessary requirements for an efficient spinning method. The open-end spinning has some limitations. It is not suitable for spinning fine-count yarn. More bulkiness results in the open-end yarn in this process. The high twist multiplier gets employed in this method. open-end resistance. This is the special character of open-end yarn getting produced in rotor spinning. The open-end yarn consists of wrapped fibres around the yarn surface. The open-end yarn also contains a thin outer layer of fibres with hardly any twist or even twist in the reverse direction. The new fibres get joined onto the already well-twisted fibre strand during each rotation of the rotor. These latecomers receive The yarn poses good abrasion at only a fraction of the desired twist level. If this low twist is lower than the false twist, the fibres get twisted in the reverse direction.



The sliver obtained from carding or draw frame is used as feed material for the open-end spinning. The working of rotor spinning can be understood in the below steps:


Sliver feeding assembly:

The function of the feeding system is to pass the sliver from the sliver can to the fibres opening assembly. First of all the sliver passes over the guide then the feed roller. The feed roller carries forward the material to the feed table. The rotating feed roller helps to grip the sliver and carries it forward over the feed table into the opening roller. The feed table is equipped with spring-loaded pressure which ensures strong gripping of the fed sliver toward the feed roller. This assembly gets equipped with automatic stop motion. When sliver a yarn end down, sliver feeding gets stopped immediately by disengaging of feed clutch. The feed roller also stops rotating. The signal pulse causing this is generated by a yarn-sensing device called a thread monitor.

Sliver feeding assembly

Fibres opening assembly:

Since a very little amount of twist gets employed to carded or drawn slivers to hold the fibres together it needs to open the fibres completely. The opening action gets performed with the help of a combing roller in the rotor-spinning machine. This roller gets covered with saw tooth wire clothing. When the sliver gets passed through a rotating combing roller, the individual opening of fibres takes place. The fibre-to-fibre opening of the material is necessary before it enters the drafting assembly. 

Fibres opening assembly

Fibres opening assembly

Fibres drafting zone:

In the drafting zone, the fibres get further opened. The parallel arrangement of fibres also gets performed. When the fibres get opened completely, these fibres are sucked with the help of a transport tube. An air current flows in this tube which carries the opened fibres to the rotating rotor. These fibres get accumulated on the inside wall of the rotor. The air current is produced by the main duct in the section and then through a vacuum in the rotor housing. A central fan is used to create a vacuum. This fan draws air by suction through small ducts from each rotor housing. To facilitate the generation of this negative pressure, the rotor box must be hermetically sealed as far as possible. The suction current in the fibre channel helps to pick off the fibres from the surface of the opening roller and send them into the rotor. In the course of this movement, both the air and the fibres are accelerated due to the converging shape of the feed tube. This represents a second draft following the nip trough/opening roller and results in further separation of the fibres. The fibres are straightened in this air current. A third draft creates upon the arrival of the fibres on the wall of the rotor. Since the peripheral speed of the rotor is many times greater than the speed of the fibres, the parallelization of fibres takes place in this zone. The arrangement of fibres improves. When the fibres slide down the wall of the rotor into the rotor groove due to the high centrifugal force generated within the rotor. The fibres are straightened finally here.

Cleaning assembly:

Most of the transport air enters only at the trash removal slot and only a small amount through the draw-off tube. One result of the centrifugal force of the opening roller is that impurities carried with the incoming sliver are expelled through an outlet of the opening roller housing. The expelled waste falls onto a conveyor belt, which carries it either to one or to both ends of the spinning machine, where it is removed by suction nozzles on each side of the machine.

Condensation system:

When the rotor revolves at a very high speed, a centrifugal force causes the fibres to collect in the groove of the rotor. A ring of fibres forms in the rotor groove. This fibre ring is then swept from the rotor continuously by a newly formed yarn, which contains untwisted fibres.

Rotor (Twist Insertion):-

Twist insertion in this spinning process is performed using a rotor. This rotor revolves at a very high speed. The rotor can achieve a maximum rpm of 1,40,000. Each revolution of the rotor inserts one turn in the yarn.

The yarn gets produced and is pulled out of the rotor with the help of the navel continuously. If nothing further were done, the rotor would be choked in no time. However, since the whole purpose is to form these fibres into a new yarn, the free end of the yarn is allowed to extend from the rotational axis to the rotor periphery. The centrifugal force (more than 100 000 times the weight of the fibre) acting at this point presses the yarn end firmly against the wall of the collecting groove, exactly as in the case of the fibres in the ring. The yarn end, therefore, adheres to the rotor wall. As the rotor turns, it, therefore, carries the yarn along, and the latter rotates around the nozzle like one arm of a crank. Each revolution of the rotor generates one turn of genuine twists in the yarn. When the yarn has reached its maximum twist level as determined by the prevailing force conditions, the yarn end begins to turn about its own axis, i.e., it rolls in the rotor groove. Now the open yarn end is resting in the binding-in zone on a strand of parallel fibres; rolling of the yarn end, therefore, causes the brush-like yarn end to grasp fibres from the ring and twist them in to give a new yarn portion, which proceeds to grasp the next fibres and twist them in, and so on. A yarn is thus spun continuously. It is simply necessary to pull this yarn out of the rotor via the yarn compensation bar using take-off rollers and wind it up on a winding drum into the cross-wound package.

Rotor (Twist Insertion)

Rotor (Twist Insertion)

Navel :

The navel is the small part of the machine. The navel is ceramic parts to produced and the navel is working on the machine the yarn is produced by the rotor to properly guide pass through the navel guide tube the navel is a different type to use in the different counts. 

Naval for rotor spinning

Winding (yarn package building):

The yarn is then taken up onto a cross-wound package, thus separating the winding process from twisting. Yarn is wound onto packages ready for use in fabric formation the yarn is a lot cheaper to produce.

production formula of rotor spinning machine:

In the Rotor Spinning process in Rotor RPM and T.M are available to find delivery speed in mts/min.


To Find TPI to Convert on TPM TPM = TPI x 39.37

To find the Delivery Speed:-

Delivery speed = Rotor RPM / TPM 

It can be calculated as follows;

Production Rate (kg/hr)
= Delivery Speed MPM X 60 X 1.0936 X No of spindle / 
840 X 2.2046 X Count 

CHAPTER 3 - Introduction to Internship

  • To know about the working atmosphere of the industry.
  • To gather knowledge about the machine, their working principle & their running condition and also their maintenance.
  • To acquire information about mill production, export & import policy
  • To know administrative set-up & labour attitude in the industry.

Training in business organization infuses among students a sense of critical analysis of the real managerial situations to which they are exposed. Our institution has given us the opportunity through training to be aware of and cope with fast rate changing technology, management policies, quality and productivity etc. This is a bold attempt to bridge the gap between the “world of work” and studies imparted by the institution.

We have worked in the concern for prepared our Industrial training report. Under the guidance of a training officer, we analysed various aspects of production. This has helped us in boosting

Up our confidence and determination, which will help us to face any situation in the years to come? 

CHAPTER 4 - Testing


  • Fully automatic High volume fibre tester with speeds of up to 140 tests per hour with one operator
  •  Modules to measure Length, Strength, Micronaire, Colour and Optical or Gravimetric Trash measurement as an additional option. Modular configuration with the facility to have an additional Length and Strength module
  • Automatic Micronaire measurement, weighment, disposal and precise engineering calibration
  • Automatic Moisture measurement ensures accurate strength values without the impact of environmental conditions
  • Bale SMART: A user-friendly software which simplifies the Bale Management process
  • True Maturity: A unique method of measurement which is traceable to image analysis values.

The function of HVI :

These are pointed out below: 

1. Length,
2. Uniformity,
3. Short fibre index,
4. Micronaire Value, 
5. Maturity index,
6. Strength,
7. Elongation,
8. Colour and trash, and 
9. Moisture content.

Components of HVI:

1. Balance
2. Barcode Reader 3. Computer
4. Monitor,
5. Keyboard
6. Printer and
7. Printer table

Application of HVI

HVI Used in Bale Management System: This is based on the categorising of cotton bales according to their fibre quality characteristics. It includes the measurement of the fibre characteristics concerning each individual bale, separation of bales into classes and lying down of balanced bale mixes based on these classes. The reason for undertaking this work lies in the fact that there is sometimes a considerable variation in the fibre characteristics from one bale to another, even within the same delivery. This variation will result in the yam quality variation if the bales are mixed in an uncontrolled manner. 

Strength and Elongation:

HVI uses the "Constant rate of elongation" principle while testing the fibre sample. The available conventional methods of strength measurement are slow and are not compatible to be used with the HVI. The main hindering factor is the measurement of the weight of the test specimen, which is necessary to estimate the tenacity of the sample.

Fibre Fineness:

Fibre fineness is normally expressed as a micronaire value (microgram per inch). It is measured by relating airflow resistance to the specific surface of fibres and the maturity ratio is calculated using a sophisticated algorithm based on several HVITM measurements.


The moisture content of the cotton sample at the time of testing, using a conductive moisture probe and the main principle involved in the measurement is based on the measurement of the dielectric constant of a material.

Trash Content:

Particle Count, % Surface Area Covered by Trash, Trash Code. Measured optically by utilizing a digital camera, and converted to USDA trash grades or customized regional trash standards.

Maturity and Stickiness:

Calculated using a sophisticated algorithm based on several HVI measurements.


4.2. PREMIER iQ2 (Evenness Tester)


PREMIER iQ 2 The Quality Expert provides total quality measurement and analysis of Yarn, roving and sliver. Critical quality characteristics, e.g. Mass Evenness, Imperfection, Hairiness Index measurement with all Numerical and graphical reports and two unique features such as hyper-sensitive imperfections & imperfection distribution.

Principle of premier Evenness Tester

Principle of premier Evenness Tester:

Raw material, as well as spinning problems, can be detected by the measurement of yarn unevenness which is done by an evenness tester or premier iQ2. The quality parameter is determined by a capacitive sensor. In this case, the yarn, roving or sliver is passed through the electric field of a measuring capacitor. Mass variation of the material causes the disturbance of the electric field which is converted into an electric signal. Which is proportional to the mass variation of the material? The unevenness is recorded as a diagram.

Advantage of premier iQ2 Evenness Tester:

  • The CV% measured by Uster give a measure of the variation of weight per unit length.
  • This instrument measures the irregularity of material at high speed (2- 100ft/min)
  • It can show both % of M.D & C.V. of material.
  • The recorder of the pen can work at a high speed of 100yds/min 


Determination of Yarn Count:

To determine the yarn count of a sample, it is needed to measure the length and weight of the sample. The equipment used for this purpose is a Wrap reel and Analytical balance or Knowles balance Quadrant balance etc. Presley's balance can be used to get the yarn count directly from the balance. When the yarn specimen supplied is not sufficient to perform the tests on the above methods, Presley's balance can be used to examine the yarn count with reliability.

Count Test Formula = 64.8/weight of one Lea.

Determination of Yarn Count


Determination of cotton yarn strength and C.S.P. by Lea strength tester.


C.S.P is the product of the English count and strength of yarn in pounds. i.e. C.S.P = Strength of yarn in pound x Count in the English system.


A lea strength tester measures the strength of one lea yarn. One lea means 120 yards. Strength is a measure of the steady force necessary to break material and is measured in pounds. The m/c works at a constant rate of extension. Assuming the specimen to be extensible and an absence of any dynamic effects.


  • To determine yarn Lea strength
  • To Calculate the Count Strength Product.


1. Cotton yarn
2. Wrap reel
3. Lea strength tester 

4. Electrical balance

Machine Figure:- 
M/c specification:
Name: The Lea Strength Tester 
Company: MAG Solvics Pvt Ltd 
Capacity: 500lbs


M/C Features

(1) Accurate determination of the strength of Lea skein. 
(2) Vertical type accommodates easily on the wall.
(3) Constant rate of extension Principle. 
(4) Strength Measurements up to 500 lbs.

Working Principle: - (Constant rate of extension)

  • At first, one lea cotton yarn is measured by a wrap reel and in this way 5 samples are taken for testing.
  • Now, the first sample is fixed with the upper jaw J1 and the lower jaw J2.
  • The m/c is started and observed the dial until the sample is torn out.
  • When the sample is torn out the m/c is stopped and the reading is taken.

Testing atmosphere:

Temperature 29 C and relative humidity -76%
Standard atmosphere: temperature- 20 C and relative humidity - 65%.
Standard atmosphere: temperature- 20 C and relative humidity - 65%.
Size - One lea cotton yarn (1 lea =120 yards). 
No. of sample - 05 


Lea Strength = 194.78lbs/lea [120yards = 1 lea]
CSP (Count Strength product) = Lea strength x Yarn Count

=194.78 x 8 = 1558.24 (CSP of the given sample)


The strength of Cotton yarn = 194.78 lbs/lea. The Count Strength product (C.S.P) = 1558.24


All the Yarn doesn't break at the same time.


It is considered that fibres having C.S.P less than 1480 are bad or weak, between 1480-1550 are average and greater than 1600 are strong. From our experiment, we see that our samples' average C.S.P 1558.24 is which is greater than the standard 1550. So finally we can say that these yarns have average-strength fibres. 

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