1. Abstract


Improving Right First Time production in a Dyehouse is of obvious benefit to that Dyehouse:


- Management(less stressful life)

- Owners/ Shareholders (more profit).


But it alsobenefits the retailer, and by consequence, ultimately the consumer.


Manyanalysts of the supply chain have reported the impact on the supply chain ofsuch sophisticated initiatives as:


- Softwaredevelopments.

- Enterprise Resource Planning (ERP).

- Lean processing.

- Sixsigma analysis.


Butrelatively little has been published on the impact of improving Dyehouse Productivityon the supply chain in general and on satisfying retailers ever evolvingrequirements in particular.


Lead timesare governed not only by distance from the target markets but also by organisationof production.

The impactof Right First Time production and increased Dyehouse production efficiencyon Lead Time should not be disputed, and should be documented.


Asretailers constantly look for new suppliers, and textile wet processing continues to shift from developed to developing economies the importance ofaddressing the basics of Dyehouse production has become increasingly apparent.

Never hasthe notion of Back 2 Basics been more necessary.


The fulltext of this article attempts to fill that void so far as the dyeing finishingof cellulosic fabrics and their blends is concerned..

It canbe accompanied by case studies taken from the authors own work experience.These can be provided on request, although all identities and confidentialitiesare carefully preserved.


ReducingLead Time without increasing Dyehouse Productivity will mean higher production costs.


ReducingLead Time by increasing Right First Time production can actually reduce total production costs.


Fig 1. CreatingWealth.


Improving Dyehouse Productivity lies at the very heart of improving profitability on existingbusiness, creating new opportunities, creating better opportunities andboosting Profits.

Table 7. TotalMetal Content by Source of Common Salt


Source

Ca ++

Mg ++

Fe +++

Unpurified Rock Salt

Source 1

1600

920

25

Unpurified Rock Salt

Source 2

2200

1800

100





Unpurified Sea Salt

1300

260

45





Purified Sea Salt

100

50

2





Pure Vacuum Dried

23

2

2






All figuresare in ppm


2.9.4 Money


Cost; Productivity; Quality and Profit.


(See sister paperCuttingCost or Creating Wealth?


Profit.


Profit is the objective which we all seek.

But do we all evaluate profit in the same way?


In its simplest possible form, UnitProfit from the dyehouse could be definedas the difference between the selling price and the cost price of one colouredbatch of production (Fig 7).


But in truth, that simple definition misses severalextremely important points relating to Right First Time production andproductivity.


Could unit profit also be defined as the difference betweenthe selling price and cost price of one coloured batch of production which has provided the following?

That coloured batch of production must provide:


- a shade which is level


- a shade which is required (ie. for which a market is knownat a given retail specification)


- a batch which does not lead to Quasi-Unlevelness ingarment confection


- a fabric which has good stitch clarity and does not leadto sewing problems in garment confection


- a fabric of acceptable dimensional stability


- a final product of good fastness which satisfies consumerdemand


- a yarn of acceptable tensile strength, robust tosubsequent knitting or weaving processes


- a yarn of sufficient lubricity and rewinding properties ?


It isnecessary to differentiate between the two alternative definitions of profit,because they have been found by this author to reflect quite differentmanagement and purchasing strategies.


It isconsidered well worthwhile examining in detail the foundations upon which eachof the two respective strategies is built.

Let usbegin with the basic definition in Fig 7.


 

Table 6. European Specification for Dyehouse Water



Parameter

Specification

pH

6.5 7.5

Total Hardness

50 ppm

Copper

0.05 mg / l

Iron

0.05 mg / l

Chloride Ions

300 mg/l



2.9.2 The Prepared Cellulose Substrate


Fig 6. Impact of Preparation Geared to Right First Time Dyeing


The standard tests for prepared cellulosic substrates are :


-          degree of whiteness

-          absorbency

-          re-wetting.


Each of these is important.

However, none of these three properties has any significant influence on Right First Time production whatsoever.

They were introduced by chemical auxiliary suppliers to promote the benefits of their products.

This author, however, would question whether these are features rather than benefits.


2.9.3 Electrolyte


This has long been known as a significant source of temporary hardness, which can exceed even that of the hardest of incoming water supplies (see Table 7).


Common salt (Na Cl) is sourced from underground deposits or by evaporation of sea water. In the latter case, calcium and magnesium impurity from discarded sea shells and mineral salts is highly likely.


 

Fig 7. Increasing Profit. From the Dyehouse



Therefore, and again in the simplest possible way, increasing the Profit

Margin can only be achieved in one of three ways:


- increasing the selling price

- decreasing the cost price

- or both.


There are two immediately relevant questions


- HOW can we increase Margin?

- HOW should we calculate Cost Price?


This is a long story, worthy of a separate consideration.

It is available as the sister papers by this author :


1)   Cutting Cost or Creating Wealth?


2)    Stretching 4 Profits.


3)   Putting Theory into Practice.


Fig 8. Profit in the Dyehouse

2.9.5. People: Basic Understanding of the principles of Reactive dyeing


* The important basic issues are shown in Table 8.


* These can only be addressed by training (available from Dyehouse Solutions International).



Table 8. Basic Principles of Reactive Dyeing



Subject

Issues

The Reactive dye molecule

Molecular Engineering.

How the molecule is built.

Which part of the molecule influences which dyestuff property.



The Dye Fibre covalent bond

How it is formed.

What determines its inherent strength.

How different reactive systems form bonds of different strengths.

Which fastness properties are determined by the stability of the dye-fibre bond.

Which dye-fibre bonds are stable to modern per-oxy containing washing detergents.


Reactive Dye systems

How do they compare for strengths and weaknesses ?

Migration

How is it determined by dyestuff properties ?

How can it be measured ?

What is the difference between Migration Potential and Migration in Practice ?

How can Migration in Practice be optimised ?

Compatibility

What determines the compatibility of a dyestuff recipe ?

And what is the impact on Right First Time production of compatibility ?

Shade Robustness to Process Variables

What do the dyestuff suppliers tell us ?

Is there anything the dyestuff suppliers are NOT telling us ?

The SERF profile

What is it ?

Why is it important ?

What can it tell us about a Reactive dyeing system, and its suitability for exhaust dyeing.


 

3. Concluding Remarks


Table 9. World Tour Summary


Number of Factories Visited

500 plus

Number of Factories Testing Prepared Fabric for impact on RFT

0

Number of Factories actively neutralising the Bicarbonate threat

0

Number of Factories achieving Theoretical SERF in practice

0

Number of Factories achieving Full Migration Potential in practice

0


A Reality Check. And Getting Back to Basics.




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2. Full Article. Retail Therapy but for Retailers:

The Global Village of Textiles and Apparel

.


2.1 Retailer Requirements (of the Dyeing & Finishing Industry)


Cost .

- Always an important issue.

- But not always the most important (see Table 1).


Relationships.

- Trust.

- Confidence.

- Reliability.


Service.

- Quality.

- Delivery.

- Stock holding.

- lead time.

- Fast response to changes.


Political issues.

- Environmental issues.

- Ecological issues.

- Social issues (child labour, human rights)

 

Product.

- Shade reproducibility:

                Lab to bulk

                Batch to batch in production.

Within each production batch.

- Colour issues:

               Colour constancy

               Metamerism / dichroism.

               Colour communication:

                     Spectral versus visual differences.

                     Choice of system

                     Consistency of Colour Standards.

                     Wide shade bands on different substrates (or same substrate).


Dimensional stability.


Fastness properties.

- Market / retailer specific.

- Fastness achieved depends not only on dye selection, but also efficiency of processing and process control (See Case Study 2).


Table 1 Changing Customer Needs


Time Period

Taken for Granted

Differentiation

1970s

Cost

Cost




1980s

Cost

Quality




1990s

Cost

Quality

Delivery Time

2000s

Cost

Quality

Delivery Time

Variety

Flexibility

Unique Look / Handle



* The Key Textile customer requirements will constantly change and evolve.

* Only those businesses which constantly strive to satisfy their customer needs will survive.


* Only those businesses which constantly strive to improve will be able to adapt to a dynamic market and changing landscape.



2.2 Retailer Survey


* The leading dyestuff manufacturer DYSTAR asked leading European retailers the following questions.


* The responses of three may be regarded as typical and are summarised in Table 2.


 

Table 2 Survey Response


Question / Issue

Retailer 1

Retailer 2

Retailer 3

Do you have any colour communication issues?

a) Spectrophotometer versus Visual

b) Metamerism and colour constancy

c) Colour standard s consistency

d) Wide shade bands on different substrates

e) Wide shade bands on same substrate

f) Lab to bulk, or bulk to bulk reproducibility



a) Yes

b) Yes

c) Yes

d) Yes

e) Yes

f) Yes



a) No

b) No

c) Yes

d) No

e) No

f) Yes



a) No

b) No

c) Yes

d) No

e) No

f) Yes

Do your current suppliers have consistency problems ?

Yes

Yes

Yes

Can you prioritise by number the relative importance of these following issues (1=highest; 6=lowest)

a) Fastness

b) Colour consistency

c) Metamerism

d) Cost

e) Shade

f) Ecology





a) 3

b) 4

c) 5

d) 1

e) 2

f) 6





a) 2

b) 4

c) 6

d) 3

e) 5

f) 1




a) 2

b) 4

c) 6

d) 3

e) 5

f) 1

Do your suppliers have problems achieving fastness and shade quality?

Yes

Yes

Yes

Do you need to find new quality suppliers?

Yes

No

No

Does your customer / brand have RSL (restricted substance lists )?

Yes

Yes

Yes

Do you or your supplier have costly Eco testing to ensure safety?

Yes

Yes

Yes


Source: DyStar Marketing: personal communication
.


2.3 Back 2 Basics : Background


This paper is designed (hopefully) to be informative and instructional rather than promotional.


It does not seek to recommend one system of reactive dyes at the expense of another. Neither does it propose to recommend one modus operandi against another. Rather, it sets out to discuss the critical success factors of a reactive dyeing operation, how they relate to the requirements of a particular form of application to the cellulosic substrate, and how they can be optimised by an audit of the basics.


The reactive dye system which might be considered optimum for pad-batch, for example, might not necessarily be the preferred choice for exhaust dyeing ( and vice versa). And, almost certainly, the preferred choice for continuous dyeing would not always be entirely suitable for exhaust dyeing.


Since the most commonly used form of application of reactive dyes to cotton is currently that of exhaust dyeing, then this paper will concentrate on that application sector.


2.4 Introduction


In todays Globalised Economy the more obvious developments of the current industrial generation concern the use of information technology in communication, and mechanisation in production.

The use of automation may apply less to the textile industry than to others which are now much less labour dependent; but still applies.


However, there is also still a part to play in the textile industry in Learning from Experience.


The basic premise of this paper is to promote the notion that Learning from Experienced Observation may be even more useful.


In this sense, there is no better pathway to success than Getting Back to Basics.


2.5 Sophistication before Simplicity


So far as the exhaust application of reactive dyes to cellulose is concerned, the dangers of introducing automation (before addressing the basics) are aptly summarised by the Third Law of Dyeing (Ottos Law).


Working examples of the cost penalties which can be incurred by placing sophistication before simplicity will be presented in subsequent papers.

Identities and confidentialities are preserved throughout.

Just one example will be quoted here, and that appears in the Summary.


Fig 1. Ottos Law of Automation


If you have a mess, and you automate, then you automatically produce

.....................................an automated mess.


2.6 Experienced Observation


This paper is nothing more than an honest Fly on the Wall documentary resulting from this authors visits to more than 500+ dyehouses spread over 4 continents over the last 15 years.


Getting Back to Basics just cannot get more basic than that.


From this experience has emerged a way of conducting a dye house techno-commercial audit which has proved successful in helping managements in Europe, South East Asia and Latin America to improve the profitability of their businesses.


 

Table 3. Dyehouse Audits by Country


Country

Number of Audits

UK

5

France

6

Belgium

3

Switzerland / Germany / Austria

6

Spain

4

Portugal

3

Italy

40

Slovakia

3

Hungary

5

Turkey

20

Hong Kong

3

Mainland China

10

South Korea

3

Taiwan

2

Indonesia

15

South Africa

5

Mauritius

8

Ecuador

5

Peru

6

Brasil

3


2.7 Main Points to Develop


Things the Auxiliary supplier never told you.


Things the Dyestuff supplier never told you.


Things the Machinery supplier couldnt even begin to tell you.

 

Things the Retailer isnt even aware of.

2.8 The 5 Basics


Cellulose (prepared substrate).

Water.


Chemicals.


Money.


People (the most important basic).


Fig 2. The Ancient Chinese Philosopher


Quote: Some People are caused by Accident.......................

..................All Accidents are caused by People.


 

Fig 3. The Basics: an Organogram




2.9 Brief Superficial Overview of the 5 Basics


It is the intention now to take a brief superficial tour of the basics.

Each basic will be reviewed in more detail in sister papers.

2.9.1 Dyehouse Water


Fig 4. The Dangers in Dyehouse Water





The most commonly recognised threat in dyehouse water is that of temporary hardness. Hardness can be a threat to the successful use of reactive, direct, vat and sulphur dyes.


The impurities which can seriously impair the quality and reproducibility of the dyeing process are :


-   Ca ++ and Mg ++ (alkaline earth-see Table 3)
-     can cause pink cotton which can be extremely difficult to remove by bleaching
-  Fe +++ and Cu ++ which can catalyse excessive local concentrations of the active peroxy bleach radical during peroxide bleaching of cotton, physical damage and even pinhole damage of the fibre.
- Fe +++ and Cu ++ can cause excessive shade change (eg. red shades move dull and blue)


The following potential dangers all carry a heavy financial burden. (Fig 5).



 

Fig 5 Influence of Metal Impurities on Reactive Dyeing



Most dyehouses soften the incoming water knowing that the effects of temporary hardness can be those listed in Table 5.


 

Table 5. Effect of Ca ++ and Mg ++ on Reactive Dyestuffs



Parameter

Effect

Impact

Solubility

Reduced Solubility

Particularly with Greens and Turquoises

Can cause dye spotting


Unlevel dyeings


Loss of dye from recipe (economy)


Difficulties in washing-off (reduced fastness)


Staining machinery (and subsequent fabric batches)


Reduced RFT; and increased possibility of customer complaint.

Aggregation

Increased Aggregation


Can cause dye spotting


Unlevel dyeings


Loss of dye from recipe (economy)


Difficulties in washing-off (reduced fastness)


Staining machinery (and subsequent fabric batches)


Reduced RFT; and increased possibility of customer complaint.

Inadequate removal from within the fibre during preparation

Can cause cloudy dyeings or even white precipitates on the fibre

Unlevel dyeings


Reduced RFT; and increased possibility of customer complaint.


Whilst softening of the water is essential for successful reactive dyeing most dyehouse managements fail to realise that it is softening alone does not give complete immunity to problems in production.


Water softening alone misses two extremely important points:


   -   the Dyehouse water is not the principal source of temporary hardness (that is the cotton itself)


   -  an even greater threat to successful dyeing comes from the presence of bicarbonates in the softened water.

Table 6 lists the European specification for dyehouse water regarded as being suitable for the use of reactive dyes.