Applications of statistical tools in various processing stages of textile production


Fiber Production

Measures of central tendency like process average gives an idea about average staple length of fibre produced in a continuous or batch wise process. Coefficient of variation (CV) of the process signifies about the process control. On the other hand, analysis of time series is helpful in estimating the future production based on the past records. Measures of dispersion such as standard deviation and CV are useful in comparing the performance of two or more fibre-producing units or processes. Significance tests can also be applied to investigate whether significant difference exists between the batches for means or standard
deviations. Analysis of variance can be applied for studying the effect of parameters of fibre production and methods of polymer dissolving.

Textile Testing of Fiber Yarn and Fabrics

Results analysis in textile testing without the applications of statistical tools will be meaningless. In other words every experiment in textile testing include the use of statistical tools like average calculation, computation of SD, CV and application of tests of significance (t-test, z-test and f-test) or analysis of variance (one way, two way or design of experiments). Populations can be very well studied by normal or binomial or Poisson’s distributions. Random sampling errors are used in studying about the population mean and SD at 95% and 99% level of confidence. Application geometric mean for finding out the overall flexural rigidity or Go has an important role in fabric selection for garment manufacture.

A special mention is made in determination of fibre length by bear sorter where all the measures of central tendency and dispersion (mean length, modal length quartile deviation, etc., in the form of frequency distribution) are computed to understand about the cotton sample under consideration for testing its potential in yarn manufacture. On the other hand ball sledge sorter uses weight distribution from which mean and SD are computed. In the case of cotton fibres, the development of cell wall thickening commonly referred as “Maturity” concept can be very well determined using normal distribution and confidence intervals. Several properties are tested for different packages produced from the same material or from the same frame by applying significance tests. Effect of instruments and variables for different types of samples can be
very well studied by using ANOVA. All the fabric properties tested on a single instrument or different instrument can be understood by using design of experiments. In one of the research applications, which include the testing of low stress mechanical properties for nearly 1000 fabrics are studied by ‘Principle Bi component analysis or Bi plot’. Measures of dispersion like coefficient of variation and percentage mean deviation are very much used in evenness measurement.

Yarn Production

There are several stages involved in the cotton yarn production. When fibres are mixed and processed through blow room, within and between lap variations are studied by computing mean, SD and CV lap rejection, and production control are studied by p and x charts. Average measure is used to find the hank of silver in carding, draw frame, combing and average hank of roving in roving frame and average count at ring frame. Generally the spinning mill use ‘average count’ as the count specification if it is producing 4–5 counts. On the other hand the weaving section uses ‘resultant count’ which is nothing but the harmonic mean of the counts produced. Control charts are extensively used in each and every process of yarn production (for example, the process control with respect to thin places, neps, etc.). Application of probability distributions like Poisson, Weibull and binomial for various problems in spinning is found very much advantageous to understand the end breakage concept. In ring spinning section several ring bobbins are collected and tested for CSP and difference between the bobbins and within the bobbins is studied using ‘range’ method. In cone winding section the process control can be checked either by using control chart for averages or chart for number defectives.

Fabric Production

Design of experiments such as latin square design or randomized block design can be used to identify the effect of different size ingredients on wrap breakages on different looms in fabric formation. Most of the suiting fabric constructions involve the use of double yarn which is nothing but the harmonic mean of different counts. Poisson’s and normal distribution can be applied for loom shed for warp breakages. Using statistical techniques the interference loss can also be studied in loom shed. Various weaving parameters such as loom speed, reed and pick can be correlated with corresponding fabric properties and are interpreted in terms of loom parameters. Control charts are used to study the control of process/product quality in fabric production also. For example, selection of defective cones in a pirn winding from a lot (fixed population) or in a production shift n p and p charts are used. The width of the cloth and its control can be understood by x and defectives per unit length and their control is understood by c charts. The testing process includes determination of average tensile strength (and single thread strength also) and the corresponding CV%.

Chemical processing and Garment Production

The scope of statistics is unlimited. For example the effect of n number washes (identical conditions) on m fabrics on a particular fabric property can be easily found by either tests of significance or analysis of variance. Similarly the effect of different detergents on fabric types can be investigated by two-way analysis of variance. Similarly different types of fabrics and the effect of sewing conditions can be studied by ANOVA.
In garment production the control of measurements and its distribution can be well understood by control and polar charts.

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The MAIN Shirt: A Textile-Integrated Magnetic Induction Sensor Array


By : Daniel Teichmann,  Andreas Kuhn, Steffen Leonhardt and Marian Walter

Abstract: A system is presented for long-term monitoring of respiration and pulse. It comprises four non-contact sensors based on magnetic eddy current induction that are textile-integrated into a shirt. The sensors are technically characterized by laboratory experiments that investigate the sensitivity and measuring depth, as well as the mutual interaction between adjacent pairs of sensors. The ability of the device to monitor respiration and pulse is demonstrated by measurements in healthy volunteers. The proposed system (called the MAIN (magnetic induction) Shirt) does not need electrodes or any other skin contact. It is wearable, unobtrusive and can easily be integrated into an individual’s daily routine. Therefore, the system appears to be a suitable option for long-term monitoring in a domestic environment or any other unsupervised telemonitoring scenario.

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The MAIN Shirt: A Textile-Integrated Magnetic Induction Sensor Array

A Review of Technology of Personal Heating Garments


by: Faming Wang, Chuansi Gao, Kalev Kuklane and Ingvar Holmér

Modern technology makes garments smart, which can help a wearer to manage in specific situations by improving the functionality of the garments. The personal heating garment (PHG) widens the operating temperature range of the garment and improves its protection against the cold. This paper describes several kinds of PHGs worldwide; their advantages and disadvantages are also addressed. Some challenges and suggestions are finally addressed with regard to the development of PHGs.

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A Review of Technology of Personal Heating Garments

SPECIFICATIONS/PROPERTIES REQUIRED FOR THE MEDITECH PRODUCTS AND THEIR TESTING


By: – T.Sureshram
Junior Scientific Officer, Department of Textile Physics,
The South India Textile Research Association, Coimbatore-14

Combination of textile technology and medical sciences has resulted into a new field called medical textiles. Medical textiles are one of the most rapidly expanding sectors in the technical textile market. Textile materials in the medical textile field gradually have taken on more important roles. The wide range of textile products used in the medical industry are classified in to four major segments namely non-implantable materials, implantable materials, extracorporeal devices and healthcare & hygiene products. This paper deals with the specifications/properties required and different types of test methods involved for evaluating the characteristics of the medical textile products.

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Testing Specification

CONTRIBUTION OF TEXTILE TECHNOLOGY TO THE DEVELOPMENT OF MODERN COMPRESSED BANDAGES


Bandage
Bandage (Photo credit: Wikipedia)

 

BY: – SVETLANA MILOSAVLJEVIC & PETAR SKUNDRIC

 

Although compression therapy is a key factor in the  successful treatment of some circulatory problems in lower limbs, this form of therapy includes some risks if used inappropriately. Based on deliberate application of pressure to a lower limb, using a variety of textile materials, elastic or rigid in order to produce a desired clinical effects,  modern compression therapy presents a good sample of successful penetration of textile technology into the phlebology field of medicine. However, although compression therapy has been in use for over 150 years, there exists a low awareness among practitioners and patients on the product usage, application techniques and benefit of appropriate selection of bandages for determined types of leg venous diseases. Also, not all manufacturers for compression textile materials seem to be conscious of end-users need. simultaneously, impressive developments in the field of elastic fibers and modern knitting and weaving technologies, offer chances for realization of completely new types of compressed bandages, capable of making an important contribution to the management of venous disease. In this review, starting from brief account of pathogenesis and the presentation of compression therapy principle, an account of the contribution of all sectors in the textile technology chain to a modern compression therapy is given.

 

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contribution of TT to the development of modern compression bandages

 

CARPET HANDBOOK


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BY – EGE

INTRODUCTION

As a skilled designer, architect, specifier, facility manager or enduser, it is important to make informed decisions when specifying carpets for a project in order to create a visually pleasing and long-lasting interior environment.

The purpose of this handbook is to provide you with the fundamentals of how carpets are made, specified, installed and maintained. In addition, aspects such as indoor climate benefits and issues related to environmental management are presented – all the basic information needed to make informed carpet decisions.

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CARPET HANDBOOK

Basic Textile Care: Structure, Storage, and Display


Textiles have been used in various human endeavors for thousands of years and have the potential to be highly symbolic and culturally important. This is especially true in the United States where even mundane textiles such as handkerchiefs and bandannas have held political and cultural significance (Collins, 1979). Due to this intimate link with historical events, items such as flags, campaign banners and bandannas, pennants, and other flat textiles stand a reasonable chance of being included in library, archive, or museum collections.

Ideally, a textile conservator should be consulted in the care and repair of a historic textile; however, this is not always immediately possible because of budgetary concerns or a lack of local or in-house specialists. In some cases, the cost of a conservator’s services may greatly exceed the monetary value of the piece (Finch and Putnam, 1985). When professional repair services are unavailable or impractical, preservation should be the focus as “the first and safest line of defense against all the causes and some of the effects of deterioration” (ibid. p. 9). To this end, this paper offers a brief overview of the structure, storage, and display of flat textiles for libraries,
archives, museums, and private collectors who may not have much experience in textile care and who lack immediate access to professional textile conservation.

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Basic Textile Care: Structure, Storage, and Display

OLEFIN FIBERS


Olefin fibers, also called polyolefin fibers, are defined as manufactured fibers in which the fiber-forming substance is a synthetic  polymer of at least 85 wt% ethylene, propylene, or other olefin units (1). Several olefin polymers are capable of forming fibers, but only polypropylene [9003-07-0] (PP) and, to a much lesser extent, polyethylene [9002-88-4] (PE) are of practical importance. Olefin polymers are hydrophobic and resistant to most solvents. These properties impart resistance to staining but cause the polymers to be essentially undyeable in an unmodified form.

The first commercial application of olefin fibers was for automobile seat covers in the late 1940s. These fibers, made from low density polyethylene (LDPE) by melt extrusion, were not very successful. They lacked dimensional stability, abrasion resistance, resilience, and light stability. The success of olefin fibers began when high density polyethylene (HDPE) was introduced in the late 1950s. Yarns made from this highly crystalline, linear polyethylene have higher tenacity than yarns made from the less crystalline. Markets were developed for HDPE fiber in marine rope where water resistance and buoyancy are important. However, the fibers also possess a low melting point, lack resilience, and have poor light stability. These traits caused the polyethylene fibers to have limited applications.

Isotactic polypropylene, based on the stereospecific polymerization catalysts discovered by Ziegler and Natta,was introduced commercially in the United States in 1957. Commercial polypropylene fibers followed in 1961. The first market of significance, contract carpet, was based on a three-ply, crimper-textured yarn. It competed favorably against wool and rayon–wool blends because of its lighter  weight, longer wear, and lower cost. In the mid-1960s, the discovery of improved light stabilizers led to the development of outdoor carpeting based on polypropylene.

In 1967, woven carpet backing based on a film warp and fine-filament fill was produced. In the early 1970s, a bulked-continuous-filament (BCF) yarn was introduced for woven, texturized upholstery. In the mid-1970s, further improvement in light stabilization of polypropylene led to a staple product for automotive interiors and nonwoven velours for floor and wall carpet tiles. In the early 1980s, polypropylene was introduced as a fine-filament staple for thermal bonded nonwovens.

The growth of polyolefin fibers continues. Advances in olefin polymerization provide a wide range of polymer properties to the fiber producer. Inroads into new markets are being made through improvements in stabilization, and new and improved methods of extrusion and production, including multicomponent extrusion and spunbonded and meltblown nonwovens.

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Olefin Fibers

Electronic autoleveller in Spinning


Electronic autoleveller is used for achieving an automatic adjustment with two different criteria of speed variation:

  • feed rate variation, for all autolevelling standard applications
  • • variation of the delivery speed when the machine requires steady feed rate like in case of linkage with other machines with the same throughput speed (for example, in the after-card drawframe combined with a set of cards).

image The first system, previously analysed, is most frequently used in this process stage. Its operation is schematised in Figure: a mechanic feeler detects the thickness of the material fed, the variations are transformed into electric signals and sent to a control unit which, with a suitable delay corresponding to the passage of the material from the feeler to the drawframe, determines the variation of the feed rate and therefore of the draft. The electronic autoleveller does not set definite limits to the possibility of adjustment but in relation to the correct detection and to the speed limit of the intersecting comb head, the suitable adjusting range applicable varies between – 25% and + 25%. It is also possible to store the maximum and minimum drawing limits beyond which the machine no longer complies with the technological operating conditions allowed for each material.