K.W. Yeung

LOW TEMPERATURE PLASMA TREATMENT OF LINEN

Low temperature plasma treatments are applied to linen with oxygen and argon at various discharge power levels and exposure times. Their effects on bulk structure, surface morphology, flax fiber properties, and related fabric properties are investigated with a range of analytical methods. X-ray photoelectron spectroscopy reveals that the surface oxygen content of the plasma treated samples increases, which is supported by the results from fabric whiteness tests. Formation of voids and cracks on fiber surfaces is revealed by scanning electron microscopy. There is no significant change in x-ray crystallinity and cuprammonium fluidity, but there is a slight reduction in moisture regain for all plasma treated samples. Fabric weight loss increases with exposure time. Fabric water uptake and strength first increase and then decrease with prolonged exposure, whereas fabric bending rigidity, hysteresis, and wrinkle recovery improve slightly.

Wicking Properties of Linen Treated with Low Temperature Plasma

The wetting and wicking behavior of linen treated with low-temperature oxygen and argon plasma is presented. Wetting and wicking abilities of plasma treated linen are investigated using contact angles and upward and downward water wicking methods. The downward wicking method is more suitable for distinguishing the effects of plasma treatment under various conditions.

Handling the assembly line balancing problem in the clothing industry using a genetic algorithm

Assembly line balancing problems that occur in real world situations are dynamic and are fraught with various sources of uncertainties such as the performance of workers and the breakdown of machinery. This is especially true in the clothing industry. The problem cannot normally be solved deterministically using existing techniques. Recent advances in computing technology, especially in the area of computational intelligence, however, can be used to alleviate this problem. For example, some techniques in this area can be used to restrict the search space in a combinatorial problem, thus opening up the possibility of obtaining better results. Among the different computational intelligence techniques, genetic algorithms (GA) is particularly suitable. GAs are probabilistic search methods that employ a search technique based on ideas from natural genetics and evolutionary principles. In this paper, we present the details of a GA and discuss the main characteristics of an assembly line balancing problem that is typical in the clothing industry. We explain how such problems can be formulated for genetic algorithms to solve. To evaluate the appropriateness of the technique, we have carried out some experiments. Our results show that the GA approach performs much better than the use of a greedy algorithm, which is used by many factory supervisors to tackle the assembly line balancing problem.

Topographical Study of Low Temperature Plasma Treated Flax Fibers

A comprehensive study of morphological and topographical changes in low tempera ture plasma treated flax fibers is reported. Time-series images of fiber surface appearance are examined by environmental scanning electron microscopy (ESEM). As the exposure time increases, the depth of the micropores etched by the plasma increases with increasing pore width. The surface fibrils remain on the surface at up to 40 minutes of oxygen plasma or 60 minutes of argon plasma exposure. The dominant fabric weight loss of linen during plasma treatment is mainly attributed to fiber surface etching. Fiber contraction is also observed during plasma treatment. The ESEM micrographs show a good correlation with the SEM micrographs. The depth of the etched pits induced by the argon and oxygen plasma is measured by atomic force microscopy (AFM). On the relatively smooth surface of an untreated flax fiber, the argon plasma creates pits of mainly submicrometer size (both depth and diameter), while the oxygen plasma creates pits of a few micrometers. Image processing techniques provide a quantitative description of the surface topography of plasma treated flax fibers, and the FFT power spectra describe periodic surface features. Changes in the surface roughness of the plasma etched flax fibers are quantified by RMS values.

Application of artificial neural networks to the prediction of sewing performance of fabrics

Purpose – This paper aims to investigate the use of artificial neural networks (ANN) to predict the sewing performance of fabrics. The purpose of this study is to verify the ANN techniques that could be emulated as human decision in the prediction of sewing performance of fabrics.Design/methodology/approach – In order to verify the ANN techniques that could be emulated as human decision in the prediction of sewing performance of fabrics, 109 data sets of fabrics were tested by using fabric assurance by simple testing system and the sewing performance of each fabrics specimen was assessed by the domain experts. Of these 109 input‐output data pairs, 94 were used to train the proposed backpropagation (BP) neural network for the prediction of the unknown sewing performance of a given fabric, and 15 were used to test the proposed BP neural network.Findings – After 10,000 iterations of training of BP neural network, the neural network converged to the minimum error level. The experimental results reveal the gr...

Fuzzy operator allocation for balance control of assembly lines in apparel manufacturing

Production processes in apparel manufacturing typically involve hybrid assembly lines. In order to perform at predetermined production rates, careful balance control of the sewing operations on these assembly lines is very important. The right number of operators to be moved in and out of a sewing section has to be accurately determined. In this paper, the authors extend the literature on fuzzy logic applications to control systems by proposing a simple, yet effective, rule-based system that captures the knowledge of experienced supervisors in a set of fuzzy rules. These rules specify how balance control can be achieved based on the level of difference between; (1) the actual and target buffer level; and (2) the actual and target section performance. Since these parameters are normally expressed in linguistic terms, they are encoded in rules expressed with fuzzy logic. The number of operators to be moved in and out of a sewing section can, therefore, be determined by means of fuzzy inferences. To evaluate the effectiveness of the system, we compared its performance to the decisions made by experienced supervisors at a large shirt factory. The system was found to increase in production efficiency by 30%.

Effect of NaOH Mercerization on the Crosslinking of Ramie Yarn Using 1,2,3,4-Butanetetracarboxylic Acid

The effect of NaOH mercerization on the crosslinking properties of 1,2,3,4-butanetet racarboxylic acid (BTCA) on ramie yarn is studied, with emphasis on mercerization tension. NaOH at mercerization strength decrystallizes the ramie fibers, resulting in a higher accessibility to BTCA. Due to the change in fiber orientation caused by mercerization, tension mercerized and crosslinked ramie yarn shows a higher tenacity than the crosslinked control, while the low-tension or slack mercerized and crosslinked ramie yarn exhibits more serious tensile strength loss than the crosslinked control.

Effect of Mercerization on the Crosslinking of Ramie Fabric Using 1,2,3,4- Butanetetracarboxylic Acid: Physical Properties and Crosslink Distribution

Ramie, tension-mercerized ramie, slack-mercerized ramie, and cotton fabrics are treated with 1,2,3,4-butanetetracarboxylic acid (BTCA) to obtain wrinkle-resistant properties, and their physical properties are compared. Tension mercerization slightly enhances the loss of both tensile and tearing strengths of the crosslinked ramie fabric, while slack-mercerized crosslinked ramie fabric has severe mechanical strength loss mainly due to the destruction of fiber orientation during mercerization. Both the tension- and slack-mercerized crosslinked ramie fabrics show increased moisture and water retention, as well as a very rigid handle. Both tension and slack mercerization minimize surface migration of the crosslinking agent.

Tensile Strength Loss of Mercerized and Crosslinked Ramie Fabric

Ramie fabric subjected to a wrinkle-free treatment experiences severe losses mechan ical properties, which is the main obstacle to developing wrinkle-free ramie goods. In this study, 1,2,3,4-butanetetracarboxylic acid (BTCA) is used as the crosslinking agent on ramie fabric to acquire wrinkle-free properties. Tensile strength losses in treated ramie, tension- mercerized ramie, slack-mercerized ramie, and cotton fabrics are investigated for acid degradation and the crosslinking reaction of cellulose molecular chains. Tensile strength loss in the treated fabrics are closely associated with the fine structure of the fibers, such as the degree of polymerization, crystallinity, accessibility, and orientation. The high crystallinity and low accessibility of ramie fibers lead to a non-uniform distribution of crosslinks, resulting in severe tensile strength loss.

Modifying an Existing Numerical Shade Sorting System Through Cluster Analysis

Our previous study compared the effectiveness of Clemson color clustering (CCC) shade sorting, originating at Clemson University, with a shade sorting process called K-means, originating at the Indian Institute of Technology. We proved that these two methods were suitable for shade sorting since their performance was very much alike. These results have led to a study of modifications of the CCC shade sorting process by combining hierarchical and nonhierarchical algorithms into a single process in order to improve the effectiveness of shade sorting.