According to an official of Apparel Export Promotion Council (AEPC), the industry is likely to achieve an export target of US$ 25 billion by 2010-11. Mr. Vijay Agarwal, Chairman AEPC said that by the end of March2007, garment exports were expected to reach US$ 9.3 billion, a growth of around 9 to 10% as compared to 2005-06. He further said that to achieve the target of $25 billion, the industry would need an investment of Rs. 35000 crores in terms of related infrastructure and an additional 1.5 million people. To meet the need of trained staff, AEPC plans to set up 50 training centers, besides the 22 centers it already has across the country. By September 2007, AEPC plans to set up six centers and an academic cell in

Gurgaon.


Fully-automated textile processing in discontinuous (batch wise) yarn and piece dyeing


For those textiles finishing plants located in central Europe automation is of considerable importance for the profitability of the company since the dyer has to cope with enormous cost pressures. In this paper, experiences with a fully automated yarn dye-house (already in successful operation for four years now) and a fully automated piece dyeing plant are described. With such automated dye houses there is a chance for survival in Europe today.


Finishing plants in central Europe under pressure


With the globalization of the textile industry, it has become increasingly difficult for the textile finisher within the European market to maintain his position. In addition to wage costs in the textile industry, this depends to a great extent on the actual costs of processing within the European continent. In view of the costs of water and effluent treatment, there is considerable pressure to reduce the costs of water consumption. The use of energy raw materials dyes and auxiliaries better processing costs per kilogram of textile material are achieved. Moreover, the quality standards of the customer continue to increase and quicker finishing, i.e. shorter delivery time are demanded.

The influence of processing costs

A distinction is made nowadays between processing costs arising from environmental considerations and those influenced by commercial factors. Under environmental considerations, water and not least its availability and, quality takes first place.


In Europe especially, it is necessary to extract water which is suitable for the textile industry as well as to discharge effluent which complies with ecological requirements into the main outfall or the municipal waste water treatment plant. The cost of this effluent treatment is added directly to the cost per kg of material processed.

Commercial requirements include shorter delivery times, reproducibility of dyeings short production times and a high standard of quality. Reproducibility from batch to batch is crucial and it is obvious that only the slightest variations in color difference between the inside, middle and outside of a yarn package can be tolerated.


This requirement, and the need to maintain the physical properties of the yarn, is achieved by the use of frequency controlled motors and pump flow rates regulated by these motors during corresponding changes of liquor flow direction, As far as the reproducibility' human intervention should be the objective in a yarn dyeing plant, i,e. with as 'much automation as possible.


Control of yarn package winding density is an absolute must. To this end, effective cooperation between the winding room and the dye house is the least requirement. Differences in material and changes of raw material must be notified in good time. ln the dyeing process, it is necessary to pass through an appropriate PH range exactly, i.e. by optimizing PH control and carrying out pH regulation with the aid of suitable control instruments. This function is likewise controlled by accurate process automation.


 

The costs of the actual dyeing process are dependent on good laboratory matching and the optimization of dyeing recipes with reduced process times. This is only possible when the dyeing process has been accurately recorded which also makes it easier to identify defects or problems created by the machine system or personnel at a later stage.


As far as liquor ratio is concerned, it should also be possible to treat different batch sizes in the same machine system under the same conditions in today's dyeing machines. This has now been made possible by the transition from usual overflow circulation to dyeing in a so-called pressurized system with this method, 8 yarn packages on one spindle can be dyed at liquor ratios between 6: 1 and 8: 1 as well as 4 yam packages per spindle at the same liquor ratio. Reductions of up to 50% maximum can be achieved with such a dyeing' machine system.

One modification of the dyeing machine system which follows directly from the liquor ratio is the installation of a heat exchanger in the pipe work system and the avoidance of a so-called tubular bundle in the dyeing vessel itself. As a consequence, a factor affecting the liquor ratio can already be reduced without impairing the function of the yarn dyeing machine in any way


First automated yarn dye house in operation P. Schomakers, Thies GmbH & Co., Coesfeld/Germany


At the Zwickauer Kammgarnspinnerei GmbH, Silberstra Be (Saxony), the first automated yarn dye-house from Thies has been realized. A detailed report on this dye house concept has already been given in [1]. Besides the automated preparation and conversion of raw yarn and the press-packing of yarn packages, a dye house equipped with horizontal dyeing machines in which vertical material carriers are dyed has been realized. The total concept has been operating successfully in Silberstra Be for more than 4 years now.


In addition to package dyeing, wool tops are also dyed in the same machine system. Carriers for yarn packages with 5, 10, 20, 40 or 80 spindles each are used which can be coupled to one another in various ways or treated individually in the dyeing machine systems available. The corresponding carriers for tops are suitable for 2, 4 or 16 cans loaded with 4 bumped tops in each case.


In the dye kitchen one preparation tank per dyeing machine is provided as well as appropriate dye dissolving vessels in a range of different sizes. The delivery of textile auxiliaries from their respective supply tanks is fully automated (MPS-L) with tank containers being provided for common liquid chemicals (e.g. acetic and formic acids).


In order to ensure a high degree of reproducibility in dyeing, intensive laboratory preparations with a Datacolor dispensing system are necessary. The entire transport system and yarn storage are fully automated which includes the loading and unloading of material carriers.


The presses used here for the press-packing of yarn packages with appropriate positioning of the top plates operate without manual intervention. For accurate dyeing, the net-weight of each batch is determined exactly and the recorded data transmitted to the dye kitchen and dyeing machine system ready for appropriate order allocation.


The liquor ratio used for dyeing is approx 7:1 which has a very favorable effect on the dyeing process in terms of the dyeing costs for energy and auxiliaries.


The realization of this fully automated yarn dye house was made possible by providing overall control with an Orga- TEX system which determines controls and regulates all functions of the yarn dye house.


Besides the loading and allocation of dyeing machines, this system also includes dyeing machine control, management and control of the dye kitchen, integration of the dye house laboratory and the entire allocation of orders with the necessary movements of material with in the dye house and the simultaneous acquisition of all dyeing data.


This dye house is of course, linked to an effluent treatment plant with integrated heat recovery so that, amongst other things, cooling water can be returned directly and the corresponding heat energy from discharged effluent is recovered by means of a heat exchanger.

 

Automation in piece dyeing as well


A similar concept has recently been realized at the firm Rositta, Sittard, Holland, where appropriate automation of the piece dyeing operation has been carried out.


This company operates a batch wise piece dyeing plant which is mainly engaged in processing cotton circular knits and their blends for the underwear market. The dye house is equipped with both atmospheric and HT "roto-stream" dyeing machines for the dyeing and bleaching processes.

The entire system is again controlled by means of an Orga TXE computer. Besides the'Q1anagement of dyeing recipes and the control of information to the dyeing machines, this system controls the dye store and the integrated paternoster as well as the corresponding dye-dissolving station.


The dye which is weighed in powder form is fed to a special dissolving on the particular dye class used, it is completely dissolved with the minimum quantities of water and temperatures required in accordance with specific programs, then transferred to the dyeing machine.


An MPS-System (Thies) which doses all the chemical dosing. The feed pipe is cleaned with the minimum quantity of water after each chemical addition all the chemicals necessary for the dyeing process have been transferred to the preparation tank. These pipes are cleaned in each case with compressed air.


For the 'solid chemical dissolving station, four supply tanks have been provided for salt, hydrosulphite, sugar and soda. These solid chemicals are delivered by tanker or in sacks and are fed to the dissolving station through a pipe work system dried with hot air.


In the solid chemical dissolving station (MPS-S) salt is dissolved at a mixture ratio of 1: 1 and the other solids at a ratio. of 1:2. A prerequisite here is the availability of a constant quantity of water for preparation.


The fully automated delivery to necessary chemicals by the computer system also requires a correct decision with regard to the particular piece dyeing machine to be used. Here the type of material and fibers involved, in these case knit-goods, is decisive.

The effect of automation should bring a corresponding reduction in the total consumption of dye house water and, of course, the design advantages of the machine such as the arrangement of the reel, the filling of the fabric storage chamber by means of a plaiter as well as the use of a rotating drum as a fabric storage chamber to facilitate tension -free fabric transport also need to be taken in to consideration here.

The control system must be capable of analyzing all processing techniques and store the production data in such a way that fault detection is also possible at a later stage.


The use of new rinsing system including among other things, continuous rinsing with exact quantities of water (CR rinsing) assisted by a 100% addition tank is also crucial here.


The possibility also exists to drain for preparation. The liquor with a liquor pump under valve. The respective solid chemical are control in order to accelerate the draining dispensed gravimetrically. The resultant process, the 100% addition tank can also a clianges or pre- d preparation of the next process baths. The so-called CCR rinsing (combined cooling a and rinsing) procedure, i.e. the use of b cooling water in the phase with simultaneous return as rinsing water can also be integrated with in the closed machine system.


A further point which must not be neglected here is the use of a suitable filter system. For a fully automated piece dyeing operation, Thies can supply two different systems. A so-called self-cleaning filter is able to filter out the lint which accumulates in the main circulation and remove it by controlled separation via a rotating system. With another filter system, which is integrated in to a so - called bypass circulation, it is possible to filter out lint continuously via a second flow and remove this lint from the dyeing machine system at every bath change.


 

Concluding remarks


An above, an average increase in the productivity of yarn and piece dyeing is only possible with a complete fully automated handling of the material before and after the actual dyeing machine. Conformity to samples can only be achieved by adopting a standard liquor ratio with the full cooperation of the laboratory, sampling and production.


Automated recipe formulation combined with automated dye and chemicals preparation contributes their share towards keeping the consumption of dyes and chemicals as low as possible.


A fully-automated dye house must also provide a high degree of flexibility in batch sizes with constant process parameters.


Finally, it should be perfectly clear that with the correct investment based on the experiences of machine makers and the dye and textile auxiliarys manufacturers, it is possible to arrive at a concept which can ensure the survival of the textile industry even in Europe.



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