Technology & The Future - Muhammad Mushtaq Ahmed

After advent of compact spinning, yarn quality parameter has changed, especially in respect of hairiness, strength and in some respect Imperfection.

Here is a research work in respect of modified spacer and cradle in further improvement of yarn quality of compact yarn & conventional yarn. Today, the main goal of companies is to achieve improved yarn quality that will ensure better competitiveness and higher yarn prices. Current spinning technology developing is aimed at how to maintain higher productivity with effective quality control, by selecting suitable equipments and spinning conditions to match with the raw materials. So, modern developments of machinery, labor demand and increasing market competition compel the spinner’s to produce as satisfactory yarn as is economically possible. Abstract: The article presents the comparison of modified spacer and cradle VS normal. I have analyzed and compared the physical mechanical etc. parameters from the same cotton, cotton/polestar (CVC) roving and same spindles were performed, in different modern group mills with state of the art machines / normal machines are described within this work. The purpose of this study to determinethe influence of modified and normal spacers and cradles on yarn quality in compact and normal spinning and to compare the produced yarn, specially Imperfection (long/short).

Key Words
Conventional spinning, compact spinning, normal spacers, modified spacer, normal cradle, modified cradle yarns, imperfection (IPI),uniformity (U %).

Introduction and Motivations
In spite modernization and rapid technological development in the field of ring spinning, the mechanism ring-traveller spindle has remained almost the same until now. Furthermore, ring spinning remains the dominant spinning technology even today. The producers of modern spinning frames have been developing the machines with improved construction of different working elements and optimal spinning geometry, with a ring diameter of 36 mm, a tube length of 180 mm and spindle speed of up to 25,000/min.

Besides the conventional functions (spindle speed, delivery speed, productivity, twist, draft, machine efficiency), computer-based system control and enable the optimization of spinning conditions (formation of bobbins, position of ring rail, automated doffing and setting of empty tubes, cleaning and oiling of main machine parts). Construction improvements of different working elements of the ring-spinning frame and optimized spinning geometry of the continuous from of fibres (roving or sliver) enable increased productivity, better yarn quality, as well as flexibility and profitability of the process.

The irregularity introduced in drafting mainly depends upon the parameters of the drafting system, mechanical faults and quality of the input material. When mechanical faults are eliminated, drafting ir-regularities depend upon to control on the floating fibers in the drafting zone. Setting between the roller nips, distance between the apron at the nip, distance between the apron at the nip, and pressure on the top roller are some of the factors. The characteristics of the sliver fed to the drafting system also exercise considerable influence on the irregularities introduced and drafting system operated under the optimum conditions. Short fiber content, neps, trash and other impurities degree of fiber parallelization and number and extend of residual hooks in the fibers together with their direction of presentation are some of the important factors that characterize sliver quality and determine its behavior during drafting.

Nutter and slater examined the effect of hooked fiber on yarn strength and found that better strength is obtained when a fiber tip is presented to the drafting system than a hooked end. Grade, Wakanker and Bhaduri found better yarn regularity and strength when majority hooks are fed as leading. Simpson, Deluca and Flori also confirmed that feeding majority hooks as leading to the ring frame contributed to poorer yarn quality and more breakages, the effect being pronounced in case of fine yarns. Apart from hooks, the fiber parallelization may also effect on drafting irregularities.

The treatment given to raw material during spinning process throughvarious machines greatly influences not only the quality of spun yarn but also its quantum. Factory like setting betwe e n r o l l e r s, d r a f t distribution, Pressure on top
rollers, shore hardness of rubber cots, spacers, type/size of ring travelers, rings, relative humidity in the plant and mixing of raw material etc, contribute towards the quality and quantity of yarn. Moisture content in the raw material especially in cotton is very important because of its direct effect on yarn strength as well as elongation and neps in the yarn. Whereas the strength and elongation directly affect the performance of yarn in warping, the neps influence surface of finished cloth and dye take up.

Fiber breakage is a very important factor, because any increase in breakage can lead to additional fly waste and greater number of ends down. Fiber breakage is a function of two main factors; the ratch setting and the roving twist. To avoid breakages, it is necessary to set the ratch longer then the longest fiber, because a shorter ratch will break all fibers greater in length. For a given ratch the extent of machine control over the fiber depend on the length distribution; a wider distribution and a longer ratch lead to lesser fiber control. The strain and distortion imposed on fiber ends during drafting due to the initial pull, continually repeated at each operation also lead to an increase in breakages. It is to be expected, therefore, that fiber will be beheaded or be tailed as a result of this stress and fatigue, the effect being more pronounced in case of longer fibers.

Material and Methods Material
These studies were carried out in modern mills with state of art machines and normal spinning mills using the same mixing, whichmills were using for there regular production, on conventional and compact systems were using. Same mixing with same preparatory process and spinning parameters with same roving and on same spindles. In each mills spinning was done minimum one week and in 2 group mills spinning is performed more than two months and yarn is tested daily on the same doff position. Results are the average of all test results done in respective mill.

Yarn Testing
All testing are done in there own mills labotry, where experiments are performed.

Quality properties of produced yarn
Quality results observed in this study in respect of IPI (short/long) 40 to 60%, uniformity 6 to 10% improvement is noted, where as others quality parameters are also satisfactory.

Results & Discussion
1-Nip distance between front top roller to top and bottom apron nip nearly 12mm and this is the distance in which fiber less than 12mm float freely here and there and with out control, which causes high imperfection (IPI) to control less than 12mm fibre in front zone Modified Spacer are used instead of normal spacer, which helps to reduce long/short IPI in different counts 40 to 60% and uniformity about 6 to 10%, where as remaining results are same or better than normal spacer. Which was the aim of this research. Experiments are done in different locations (Punjab & Sindh) with medium and long cotton, even on CVC also and same trend is noted.

2-In ring spinning there are two drafting zone, one is front zone and second is back zone. In back zone Modified Cradle are used. The reason to use modified cradle was to aligned fiber more parallel and with less hook before entering between top and bottom apron, which also help to improve quality parameters like long/short IPI, uniformity etc.

3- Combination of modified spacer and cradle both. Improvement is also noted. For detail please see count Tex 9.84 (Ne 60)

Work in progress
For more detail work on above subject are still in progress on different count on different locations on different medium and long cotton, carded, semi-combed, combed and cotton blended yarn. Studies on Autocone cuts, classimat etc; are also in progress. Also studies are in progress in down stream processes.

Conclusions
On the basis of this study there is more room for improvement with different combination.

About the Author

• Presently involve in R&D (Research and development).
• Qualification: M.sc, C.Txet.ATI (Textile Institute Manchester, U.K), ICS Diploma in, “Carding & Spinning” from Pennsylvania (USA), ITC from, “City & Guild” London (UK).
• Training/Courses from, Germany, Italy, Japan, Switzerland & China.
• Management Training Course from, “The Association of Overseas Scholarship” (AOTS) Japan. Leadership Improvement & Communication in an Organization” (AOTS) Japan. “Kaizen Management, Cost & Profitability Analysis” (AOTS) Japan. “Auditor / Lead -Auditor” IQA-IRCA (U.K), “Introduction to ISO 9000:2000”.“Internal Quality Auditing for ISO 9000”.
• “Energy Conservation in Industry” (ENERCON), Training / Courses etc.
• Specialization in Compact Spinning.
• Mills experience 20 years in reputable groups and mills (Manager to Technical Director)
• Research experience 2 years as, “Senior Research Officer” (SRO) in,“Pakistan Institute of Cotton Research & Technology Karachi” (PICRT) Pakistan Central Cotton Committee (PCCC) “Ministry of Food & Agriculture, Government of Pakistan”
• Teaching experience 1 year in, “Institute of Leadership & Management” (ILM) Lahore
• Consultancy experience 12 years in, Group & Reputable Mills
• Publications more than 50 in different journals.( National / International)