A Comparative Study on the Performance of Lap Fed and Chute Fed Carding System

A Comparative Study on the Performance of Lap Fed and Chute Fed Carding System
Author: Mainak Mitra
College of Textile Technology, Berhampore,
University of Calcutta



 
 
 
 
INTRODUCTION
Carding is the critical operation of cleaning and opening of fibres. Raw material in the form of individual fibres or at least in clusters of a small number of fibres is prevalent for desired quality of final yarn. Conventional way to feed card is lap, processed from blow room. But a close examination of the lap reveals the following blemises :
  1. Fibres remain comparatively in bigger size.
  2. Many of the impurities lie within the lumps of cotton due to the compression of fibres during lap preparation.
  3. Extent of opening achieved, is defeated to a great extent due to frequentcompres-sion of fibres during lap formation.
  4. Additional costs in terms of scutcher operation, lap transportation, card stoppages and lap wastages.
  5. On the other hand chute feed processes open-out cotton, directly feed to card keeping the above mentioned disadvan-tages at bay. But feeding the cards here have some adverse effects on the quality of the card sliver as well as the delivered material in the subsequent stages.
  6. From productivity point of view C.F carding is advantageous than that of L.F.
  7. Taking into account the advantages and disadvantages of chute feed arrangement it is expected to be worthy to study the system in details and compare its performance with that of the conventional one.
SCOPE OF THE PRESENT STUDY
In the present project it will be attempted to study the quality parameters of card slivers as well as the finished yarns made from chute feed and lap feed system, maintaining the standard setting parameters on both the systems being applied on cotton materials in a controlled mannar.

Card Sliver :
  • Weight regularity : by wrapping method, by uster
  • Nep count
Finished Yarn :
  • Nep count
  • Uster and imperfection(thick, thin, neps)
THEORY AND LITERATURE
The blow room machinery is linked to the cards by trunking and the opened cleaned cotton is conveyed by pneumatic means to each card – this the principle of chute feed system.

The basic elements of chute feed system are :
  • Conveyor system to carry material from B/R to group of cards with the help of air.
  • Proper control of air pressure in the conveyor system for smooth flow of material.
  • A mechanism to feed the material at uniform weight per unit length and width.
  • A delivery system to feed the material to the card feed roller.
  • A sensing mechanism at chute to keep a certain amount of material as reserve and also to control the feed of material to the chute.
Present development :
  • Automation – bale to cone : continuous automated spinning (CAS) in Japan
  • Platts chute feed system type 685
  • Exact feed FBR chute feed system by trutzschler, germany
  • ML snowflaker chute feed by U.S.A
  • NSE chute feed system of bombay
  • Vibra chute DS by W,.Germany
  • Rando level feed by U.S.A
  • Transautomal by Italy
  • Aerodome by Switzerland
Views of Indian Mills :
The only reservation that seem to have is that its introduction in the processing line may result in high yarn count variations. This should not be so since C.F system has gained good acceptance in all the textile mills in advanced countries.

Lap Feed Demerits
  • Stoppage due to lap changes.
  • Extra labour for lap trasportation
  • Compression of fibres in the lap poses problem during opening in carding.
  • More wastes due to lap tails and damages.
  • Irregularity of sliver weight due to improper unwinding of laps.
Chute Feed Merits
  • Direct automatic feed to card increases B/R working efficiency.
  • Elimination of Man power during scutcher operation.
  • Processing of rejected lap is avoided.
  • Due to loose form of feeding of fibres trash particles can be removed easily during carding.
  • Suitable for synthetic fibres of bulky in nature, avoiding
CHUTE FEED ADVANTAGES
  1. Irregularities due to lap licking in high humidity.
  2. Elimination of irregularities due to double laps, lap splitting, lap piecing etc.
  3. Reduction of 1% C.V in chute feed carding system.
  4. Difficulty in removing of crushed foreign materials and trash during calendering is reduced.
EXPERIMENTAL PROCEDURE
The purpose of present work with the evaluation of yarn parameters of chute fed materials by means of standardisation of setting parameters in various downstream processes right from blow room to ring frame, brought about by aerofed and conventional lap fed mechanism. Various studies from cotton mixing to yarn have been made up.

SPINNING PROCESS MACHINERIES
Spinning process
RESULTS AND DISCUSSION
Parameter
C.F
L.F
Cotton fed : gm
500
500
Waste(B/R): %
8.07
7.91
Clg effy(B/R): %
64.49
63.65
Nep genrn (B/R): %
250
186
CV  %   L-L yd-yd
1.30
0.84
Clg effy (card)  %
97.1
96.8
Uster (card) %
4.01
3.56 
Count
29.6s
31.0s
CSP
1915
2340
Total imperfection
328
170
Uster (U%)
16.0  
14.0
Count CV %
4.4
2.8
Nep redn(card) %
51.14
53.40
Single strength
252gm
271gm
Strength CV %
11.9
8.8
Elongation %
5.2
5.5
Tenacity (gpt)
12.6 
14.3
Power involve(HP)
75 
50
 
DISCUSSION
From the productivity point of view chute feed spinning method is advantageous over lap feed. Lap feed process is a quality oriented product where as in chute feed to keep quality of the final material within a standard level is a difficult phenomenon.

The flow of material althrough the C.F line is always more or less keeps a whirling turbulance of air. This causes the fibrous material to go-around before finally reaching the licker-in zone of card and making the fibres uncontrollable. Technically speaking the primary leading hooks of the material may appear as a trailing hooks and vice-versa. Due to the tendency of all the fibrous materials to change its own direction of flow by means of different curvature of ducting of aero feed process. apart from the changing of trailing hook and leading hook the fibrous material is specially short floating immatured one, which may turn into a ball like formation, known as Nep.

CONCLUSION AND SUMMARY
It may be stated that with this coarser variety the overall level of yarn quality disimproves. As long as quality values of yarn are concerned with B/R scutcher line card system may possess an overall superior quality than compared to aero feed technology.

SUGGESTION FOR FURTHER WORK
  • Experiment may be done with a wide range of mixing.
  • Experiment may be extended on computer.
  • Blended yarn of different mixing may be processed.
  • A detailed time oriented processing may be done.
  • Properties like stiffness, smoothness, abrasion resistance, cleanliness and moisture content may be tested.
  • Fabric properties made from these two processed materials may be examined.
  • Dye-uptake property of yarn from C.F & L.F processed may be tested. 
 

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