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e-Consulting by CARBOTEX

Cost minimization through process engineering supported by convenient product selection

Last updated: 17^th August 2001

In some opportunities it has been reported to us that the methods we are recommending and been used in several Dye Houses since a lot of years, are methods and strategies allowing to use all kind of products, including those of low quality (and consequently of low prices).

It is very convenient to clarify here a lot of aspects related to this unfounded opinion.

First at all, some definitions:

Cost minimization: the main tools / areas to achieve such reduction are:

improving RFT, RST, JIT, or said in other words: reducing time of elaboration of new recipes (RFT/RST) in lab and ensuring good results in the first lot in the production),

avoiding corrections in lab and in production,

achieving the best possible Color reproducibility in the lab, in the plant and trespassing from lab to plant,

ensuring the less expensive process, decreasing manual interventions, saving water and energy (electrical and thermal), using products and dyestuffs with a balanced equilibrium between cost and performances, specially continuous constancy of quality, decreasing the cost of effluents treatment,

limiting the occupation time in the production machines knowing which has to be the "so long as needed",

avoiding rehandles and redyeings ensuring the correct levelness and correct fastnesses in the plant (designing the correct process parameters according to machine, recipe and actual quality of used textile goods),

using products and dyes in the more convenient economical and ecological conditions, establishing the most efficient product profiles including test methods, etc.

learning to determine most convenient quantities of auxiliaries, avoiding generic rules,

It is obvious that the must adjusted are all the parameters intervening in the dyeing process, the best can be fulfilled the above mentioned requirements. But an "adjusting of parameters (including recipe’s and process parameters)" can be only accepted if these parameters don’t have to be totally adjusted for each production order resp. each lot. By the way, the used dye goods can present variations from lot to lot or from delivery to delivery or from preparation lot to preparation lot, etc., and this fact acquires nowadays a crucial importance, that means, additional and very accurate controls and systems have to be introduced in the plants in order to improve the reproducibility of dyeing results. Adjustments of the process parameters should be consequently carried out due to these possible variations in the behavior of the gray goods. It is possible to simplify these adjustments adopting methods allowing to define classes of affinities and of kinetic behavior and using such classification in the implementation of the actual parameters for each production lot.

Theoretical could be accepted the fact that also the products and dyestuffs could be classified according to the ranges of variation covered by the producers. It is obvious, that such suppliers adopting severe quality controls in the production of auxiliaries and specially of dyestuffs, can help a lot ensuring tolerances which can be pre-established according to the needs of the customers. In productions of a very few lots a day and accepting terrific costs of adjustment, could be accepted that even the auxiliaries and dyestuffs can present large oscillations of qualities to be compensated by a heavy adjustment work previous to the production of each lot. Simple rules are not useful and absolutely not possible, because – only one consideration of a lot of these! – each product resp. dyestuff interferes with the behavior of the other components in the used recipe.

CARBOTEX Consultants has never proposed to use products (f.e. auxiliaries resp. dyestuffs) of low prices resp. quality because that would be the major factor making very difficult to reduce the cost of the production in a dye house. The cost of products are important, but they never account more as 50% of the total cost of a dye lot (normally between 20-40%) . With low quality products the risk of increasing the "non-products depending costs" is too big!

It will be continued…

(*)© Copyright: Dr. J. Carbonell & Dipl. Ing. P. Carbonell-Klempt