Massive Job Cuts Looming in Textile Industry

Massive job losses are in the offing in the textile sector, says the theApparel Export Promotion Council (AEPC).The high prices of cotton have pushed up the cost of the fabric andthe end product. We are now in a situation where we are forced to rejectrepeat orders as we can’t justify the high prices to our foreign buyers.

Labor Shortage Looming Ahead?

The large quantity of cheap labor resources has long been regarded as one of the important factors that make it possible for China's economy to maintain rapid growth. However, Cai Fang, Director of the Institute of Population and Labor Economics, Chinese Academy of Social Sciences, warned at a lecture in early May that China's surplus rural labor force is not as large as thought and that China will soon experience the transition from labor surplus to labor shortage. He predicted that the turning point would occur probably in 2009. In response, Hou Dongmin, Director of the Institute of Population, Resources and Environment of Renmin University of China, and Deng Yuwen, researcher at the China Society of Economic Reform, analyze the expected impacts of transition on China's future growth mode (in sequence).

短跑全程跑技战术调控

通过对世界级短跑运动员在世界田径锦标赛上一些成绩的比较分析,提出了短跑项目在比赛中合理分配速度、合理应用战术的方法。在重视技术训练的同时战术训练也是不可忽视的。

An Analysis of the Orthogonal Crank-rocking Lever Spatial Mechanism for the Weft Insertion in Rapier Looms

On the basis of the analysis of typical orthogonal crankrocking lever spatial mechanism for the weft insertion in rapier looms, the rules of the outputting lever motion and the mechanism pressure-angle variety are studied when the maximum swing angle of rocking lever and the length of outputting lever have different values, and the optimum parameters suitable for motion transmission can be chosen. At the same time some existing shortpoints of the mechanism are also pointed out.

CONJUGATE CAM WITH FIVE-BAR LINKAGE MECHANISM FOR RAPIER DRIVE OF FLEXIBLE RAPIER LOOMS

A new type of rapier drive for flexible rapier loom through conjugate cams with five-bar linkage mechanism is raised and analyzed. Two designs suitable for the conversion of 1515-190.5 shuttle looms are given as examples. This mechanism can be applied to traditional shuttle looms as well as to new flexible rapier loom design.

MODIFIED MOTION PATTERN OF LOOM RAPIER

A modified trapezoid acceleration pattern with a constant speed part is introduced for loomrapier motion driven by cam.The pattern can meet the time requirement of rapier on entering andleaving the shed,and can satisfy the condition when the period duration of inserting is not equal tothat of withdrawing.Meanwhile,the pattern can also reduce the maximum acceleration of rapierand make the derivatives of rapier acceleration change continuously without any abruptness ofjerks.

THE POTENTIALITY OF ENERGY-SAVING IN SHUTTLE LOOMS

In this paper,the effects of loom speed fluctuation on the mean speed and on the power ofdriving motor were investigated and the expressions for these effects were derived.Based on theenergy relationships,a new index of equivalent fluctuation was introduced,the connection be-tween this equivalent fluctuation and the energy of speed function on frequency domain was thenfound.In addition to the above theme,the residual kinetic energy of the shuttle and pickingmechanism,taken as a considerable part in the potentiality of loom energy-saving was also ana-lysed.According to the results of theoretical analyses,the ways of energy-saving in looms weresuggested.Finally,taking the loom of 1511 type as a practical example,the potentiality ofenergy-saving was calculated.

RECONSTRUCTION OF AXLE-TREADLE LOOM IN HAN DYNASTY

The axle-treadle mechanism of Han loom consists of a set of components, including two pedals controlling one shaft via a central axle. Based on the new archaeological finds, especially the pottery loom model, the collection of Krishna Riboud, and the historical document, a kind of axle treadle loom with oblique warp frame was reconstructed by author. It might be applied in the central China at that time, especially in Shandong and Jiangsu areas, and it was not later than the Warring State period for the oblique axle treadle loom to come into being and reach a peak in the Han Dynasty. After that time, it was used with the vertical frame but lost the importance gradually.

KINETO-ELASTODYNAMICS OF A FLEXIBLE RAPIER LOOM

For a complicated high speed reciprocating machine to meet the requirements of precise motion of its mechanisms, a study of its kineto-elastodynamies is necessary. Here is an example to find out the cause of the misengagement of flexible rapiers, by means of kineto-elastodynamic analysis, so as to meet the requirements of flexible rapier loom′s design, with beat-up and weft insertion mechanisms operating at high speed.

Review and Prospect of the Shuttleless Loom Development

In this paper, a review of the shuttleless looms’ development shows that three types of shuttleless looms: rapier, Jet and gripper projectile, are now equally matchable with each other. A prospect of the shuttleless loom’s development is also dealt with. It can be predicted that both rapier and Jet looms will be developed further and the future development of a new type of modern weaving looms will be prosperous in the coming 21st century.

A STUDY ON THE DYNAMIC RESPONSE OF CAM BEAT-UP MOTIONS FOR RAPIER LOOMS

Based on the requirements of the two-phase rapier loom’s beat-up system characteristics, the dynamic responses of its beat-up system to three different types of cam input motion are studied in this paper. Also, their corresponding analytical comparisons are made. At the end of the paper, the authors put forward a proposal of new type cam beat-up motion for future practice.

A THEORETICAL ANALYSIS OF WORKING CHARACTER OF WEFT TENSION COMPENSATOR IN NEEDLE LOOMS

Based on the analysis, according to the principle of vibration, of the working character of weft tension compensator in needle looms, the paper studied the principle of tension compensation and introduced the idea of compensating coefficient. The paper also discussed some factors affecting the effect of tension compensation.

An Analysis and Prevention of Stop Marks in Weaving

The cause of stop marks of fabrics in weaving is introduced, and the floating displacement of the cloth fell during loom stoppage is a primary cause of stop marks. The stop marks caused by fabric system are analyzed. A new method to eliminate stop marks by using the electronic let-off system is presented. This new method needn't any special detecting equipment, it can control the fell position by the powerful control program,so the cost is decreased greatly. The method is so flexible that can be applied to weaving all kinds of fabrics.

DYNAMIC PROBLEMS OF WATER JET FOR WEFT INSERTION

In recent years, China has imported thousands of water jet looms. In order to master thetechniques and to develop the variety of products, the dynamic problems of this jet device hasbeen discussed in this paper briefly. It contains 1. Introducing the rotary plunger pumps and the open-type jet nozzles. 2. Establishing the fundamental equations of the dynamic analysis for water jet device. 3. An illustrating example to show the jet speed, and the rate and time duration for the jetflow varies with different pipe resistance, cross section area of the nozzle outlet, and the springcompressive deflection etc. It is useful for research and production references.

Relationship between Beating and Setting-on Place

In this paper,what causes the setting-on place of woven fabrics without adopting tension compensation is explained by means of experimental methods.Owing to that the main shaft speed and the beating speed of reed can not attain the normal values at setting-on,the warp tension and the beating force of the reed can neither reach the normal level.Therefore,the relative slippage movement of the weft against the warp during beating will be less,while the common movement of the weft together with the warp will be bigger than those at nor-mal running.As a result,the setting-on place is

Dynamics of Water Jet in Water Jet Looms

On the base of the study on dynamics of water jet in water jet looms, the parameters of water jet mechanism which affect the speed of water jet are analyzed and optimized. So the stability of the water jet can be improved to raise the speed of water jet as well as weft insertion rate and to enlarge the width of woven fabrics a lot. At the same time it also points out that to increase water jet speed and to prolong its affective jet time depend mainly on the accretion of spring rate (constant)of stiffness and the diminution of plunger's cross sectional area respectively.

A NEW APPROACH TO MANUFACTURING 3D WOVEN PREFORMS USED FOR STRUCTURAL COMPOSITES

The manufacturing of three-dimensional textile preforms used for composites started to re-ceive much attention in the last decade.The major barriers to accelerating the transition from thelamination of two-dimensional fabrics to manufacturing integral three-dimensional near-netshaped textile preforms are high cost and database deficiency.To reduce the cost of weaving three-dimensional preforms,and make full use of the potential of conventional looms,a rig was designedwhich can convert two-dimensional woven fabric to particular three-dimensional preforms wherethe yarn is orientated in the directions of maximum stress.

Design of Electronic Weft-Insertion System for Three-Dimensional Loom

The motion laws for rapier weft insertion mechanism are analyzed. According to the special requirements on rapier loom's weft-insertion system for weaving three-dimensional( 3-D) fabric,a new rapier electronic weft-insertion system is presented. The design principle for 3-D loom's weft insertion system is introduced,including the design of the motion law of electronic weft-insertion system,the driving system's hardware configure,and its software's controlling principle. The weft insertion system is computer-controlled and servocylinder driven so as to control the rapier's movement to insert the weft into the multi-shed while 3-D weaving. This method greatly simplifies the weft-insertion system,achieves weft-insertion with variable travel,and improves the flexibility and reliability. The weft insertion system has been applied in a 3-D loom successfully.

Dynamic Modeling of Variable Stiffness and Damping for Spatial Linkage Weft Insertion Mechanism with Clearance

In order to further analyze the influence of clearance on the kinematic performance of spatial linkage weft insertion mechanism,it is necessary to study the dynamic characteristics of contact impact force model with the variable stiffness and damping coefficient.Firstly,the parameters in the output process of the system are solved by describing of the flexible joint clearance.Then,based on Lankarani-Nikravesh contact force model,the contact impact stiffness and damping coefficient is modified from fixed values to time-varying coefficients.The dynamic model of spatial linkage weft insertion mechanism with modified clearance is established by Lagrange method,and the dynamic characteristics of the system are calculated.The results show that the joint clearance can directly affect the output performance of the mechanism.With the increase of the clearance value,the curve fluctuations of acceleration,driving torque and collision force are obvious,and it will be further intensified with the increase of spindle speed,which greatly affects the stability of mechanism and fabric quality.Finally,the virtual prototype is established by the SolidWorks software and simulated by the ADAMS software.The simulation results are compared with the numerical results,which verifies the accuracy of the modeling method in this paper.

An Overview of the Development of Novel Textile Design by the Application of Creative Components of the Chakma Community of the Chittagong Hill Tracts in Bangladesh

In the world, there are more than 370 million indigenous and tribal people with especial culture and traditions. The Chakma’s is one of the groups of indigenous people dwelling Chittagong hill tracts in Bangladesh. Chakma’s has its own culture, tradition, literature, and costume designs. The design costumes of the Chakma’s play an essential role. The Chakma’s preserved their textile design in “Alam”. Alam is a kind of cloth embroidered with various designs carrying the heritage of the Chakma. The use of Alam began approximately 500 years ago. All used clothing in Chakma society is weaved manually in the back-strap loom, which is generally very time-consuming— this limits its design aesthetics and universal use. Because of globalisation, the use of the traditional design of Chakma’s are threatened today. Till today in our country and overseas, no attempts were taken for research of the traditional Chakma’s design. The purpose of this research is to upgrade and digitise Chakma’s designs. Furthermore, efforts were made for the automatization of the traditional process to preserve traditional Chakma’s designs. In this study analysis of the fabric designs, pattern structure, colour applications of the traditional Aalam design were constructed using small prototype Rapier loom technology. We found that most of the single designs of the Alam were possible to weave in small prototype modern loom. On the other hand, intricate designs were not possible to weave in small prototype loom but are possible in the jacquard loom. The key idea is to establish an approach to modernise the traditional weaving process in order to make it convenient, economical and less time-consuming.