Comber Data Pc-Program ver 1.0

This program is for use on IBM-compatible PCs to compute important fibre parameters and optimum noil percentage as well as to check the functioning of nippers,top comb and combing cylinder through" Knowledge Based Problem Analyses and Problem Solving Techniques"developed by ITRU GROUP LTD.

1.Purpose of the program

COMBER DATA BY ITRU GROUP LTD. program has been developed through many years of research and experience carried out in spinning mills. This program makes use of the Itru Fibre Tester UAK-1 instrument to be more valuable to the spinning mills by determining short fibre content by number,coefficient of fibre length variation by fibre number and mean fibre length by fibre weight as well. Drawing the fibre weight staple curves from only two readings of span length values 2.5 and 50% by comparison of the staple curves of comber lap and combed sliver, one could analyze the efficiency of combing action.

Combing of cotton is an high cost of yarn manufacturing process. The yarn must meet required quality parameters with a minimum noil percentage possible. The intention in mills is usually to increase the noil percentage to achieve better yarn quality parameters. But it is clear from our experience that optimum yarn quality could only be achieved if the combing action is carried out well i.e. by removing short fibres. An increase in noil % does not necessarily mean that the short fibre content is reduced in sliver, it could even get worse. Therefore,this program checks whether the combing action is successful or not by comparing short fibre content in the comber lap and in the sliver as well as checking the trailing and leading hooks fibre breakage.

The program also compares the actual and recommended combing noil percenta- ges and suggest an advisable noil range. Therefore,it is possible to carry out tests to achieve best results till the combing is OK.

Combed Yarn Quality depends on mainly following factors

-Removal of short fibres

-Removal of Immature Fibres and White Specs

-Removal of Yellow Fibres and Immature Fibres

With Fibre Tester UAK-1 + all these parameters could be checked. Micronaire Histogram of Combed Noil and Combed Sliver obtained from Itru Fibre Tester UAK-1 clearly shows the removal of immature fibres by the Combing Machine .

1.1 Computation of short fibre content by fibre number

This program computes short fibre content by fibre number from the 2.5 and 50% span length values measured on Itru Fibre Tester UAK-1 of comber lap,combed sliver and combing noil. Computation of short fibre content by fibre number would give information to check the combing efficiency of top comb,combing cylinder and nippers.By comparison of back and front clamps one could determine the hooked fibre content and fibre parallelism. It should be stated that 2.5 span length values would not only be taken into account to determine the cleaning efficiency of short fibre content. The reasons are as follows:An increase in 2.5 span length values could be due to removing fibre crimp or permanent extension of fibres. Therefore having greater 2.5 % span length values in combed sliver could lead to fibre breakage in draft zone of ring spinning. Therefore,we advise you to just check the span length values of combed sliver and ring pnomophil waste values which makes the actual yarn. According to our experience carried out in different mills that setting the draft zones according to the 2.5% span length or minimum evenness values would not lead to good quality of yarn and does not represent the real facts. Therefore,the processes after combing should be checked in accordance with the short fibre content by fibre number rather than 2.5 % span length values. However,we must state that the short fibre content by fibre number is more important at combing than the processes after combing. In order to achieve optimum yarn quality draft zone settings and draft organization should be taken into a consideration. For this purpose according required linear irregularity value (CV%),we have developed a new program called"LOG-CV- DRAFT ZONE SETTINGS" which would give you the information whether your draft zone settings are in accordance with the yarn quality and whether producing H1,H2,I1 and I2 faults on yarn. This program will be available upon request.

1.2 Computation of mean fibre length by fibre weight

This program also computes mean fibre length by fibre weight from 2.5 and 50 % span length values. Mean fibre length by fibre weight is important especially in combing because it is not possible to determine the percentage of short fibre removal from fibre-number distribution diagram. Therefore,by comparison of mean fibre length of combed sliver,comber lap and combing noil it is possible to evaluate the combing quality.

1.3 Computation of coefficient of fibre length variation by fibre number

The program also computes the coefficient of fibre length variation by fibre number which is a very important parameter which would give valuable information about the fibre parallelism and distribution of single fibre length values. Higher the coefficient of fibre length variation greater the fibre problems would be in subsequent processes after combing.

1-4 Computation of minimum and maximum noil % according to comber lap

Percentage of short fibres should be removed from comber lap, would depend upon the fibre-length by fibre weight staple diagram of comber lap which could not be obtainable from Itru Fibre Tester UAK-1. Therefore,we have developed a program which determines the staple curve of comber lap by fibre weight. From this curve it is possible to fix fiber length which could be taken as a short fibre. We have taken fibres shorter than 12.5 mm as short fibres to start with. Maximum noil percentage would then only be decided upon the quality of yarn but should not exceed the value given by us.

1-5 Computation of combing quality index

The program computes the efficiency of combing action by the effective short fibre removal according to combed lap. Therefore,by making comparison of different combing machines one could identify the off-standard functioning machines. In theory 100% combing efficiency is possible,but in practice this never occurs. No combing machines could remove all the short fibres because some long fibres are dragged long with short fibres.

1-6 Computation of combing noil percentage according to comber lap and detaching roller setting and total draft

The program also computes the noil percentage according to computed comber lap fibre weight staple curve and detaching roll setting which correlates 95% with the actual results obtained. The program in addition to that given total draft lap weight,count delivered also computes noil percentage.

1-7 Computation of Fibre weight staple curves

This program plots 7 fibre weight staple curves comber lap,combed sliver and combing noil respectively. By comparing the staple curves of comber lap,combing sliver and combing noil one could analyze how the actual combing action is carried out whether there are long fibres in the combing noil and short fibres broken in the combed sliver.

2- Program structure

The program is composed of 4 subsequent programs linked to each other. program is structured in such a way that all the information could be stored in another file and then could be edited and sorted for future analyses and the relevant data could be written. Therefore,these programs would motivate your technical staff to work harder and to overcome problems in combing and subsequent processes.

The program also analyses the actual combing action . If the actual noil percentage is higher than computed value due to leading or trailing hooked fibre breakage and not properly functioning of top comp,combing cylinder and nippers it states that COMBING IS NOT OK . For this purpose the program makes use of other information developed by ITRU GROUP LTD.-International Textile Consulting & Management"KNOWLEDGE BASED PROBLEM ANALYSES AND PROBLEM SOLVING TECHNIQUES."

3- Data and results output

Samples

Output values are shown in the SUMMARY OF FIBRE DATA RESULTS AND STAPLE DIAGRAMS

4.0 Mill Work With Comber Data Pc-Program

It has been observed through our Yield Performance Pc-Programs and Process Optimization R&D Mill Works that combing noil constitutes approximately 50 to 65 % of total waste in ring spinning. Therefore,reduction in combing noil percentage with optimum yarn quality will reduce the manufacturing costs and improve the spinning and weaving performance. We have observed that combing noil could be reduced and better yarn quality could be achieved. Following figures compares two combed spinning mills using the same fibre type with different combing noils percentages but achieving different yarn strength values. It is interesting to note that MILL A having 17% of combing noil percentage has achieved better yarn strength and strength variation than MILL B running with 22% of combing noil percentage. We have also observed that combing noil % could be reduced to 12% in MILL A for weaving yarn. It is very clear our works carried out in spinning mills that PC-PROGRAMS certainly bring new conceptions to spinning and weaving mills to achieve minimum manufacturing costs and optimum quality of yarn.

	MILL A	MILL B	MILL C
Fibre Type	Izmir 1 1/8	Izmir 1 1/8	Izmir 1 1/8
Combing Noil %	14	17	22
CV% Evenness	11	13.4	13.2
Yarn strength cn/tex	15.6	15.8	15.2
CV% Yarn strength	6.5	5.6	9.9
Elongation %	5.5	7	5.2
CV% Elongation	6.5	5.5	9.8
Yarn Count	30/1 hosiery	30/1 hosiery	30/1 hosiery

Table 1.Comparison of combing noil % in three spinning mills

It is clear from experimental results that combing noil % should not be determined by trial and error method but it should be carefully analyzed and minimum combing noil % should be obtained with optimum yarn quality. Combing noil percentage depends upon mainly following factors:

a)Fibre type
b)Combing lap preparation
c)Combing machine adjustments and maintenance
d)Yarn end use knitting or weaving yarn
e)Technical Data/Machine Settings after combing

Therefore,we have following mill control systems and PC-programs to achieve lower combing noil % with optimum yarn quality.

-Process/Quality Control Assurance & Control
-Process Management Systems
-Fibre Mix Search & Selection Control PC-program
-Bale Management PC-program
-Draft Zone Setting PC-program
-Spinning Mill Data Bank+Textile Technology & Spectrogram Analyses
-Waste Control Systems+PC-programs
-Maintenance & Checklists procedures

To improve spinning mill performance is a complete process of work. And small changes make larger differences in the profitability ratio of any mill. And PC-programs are without doubt the main key for these aims to be accomplished. Any mill could see the effects of small changes making large differences in the quality and productivity levels of mills will have a greater chance of competitiveness in the international trade. For minimum cost of manufacturing and optimum quality and better spinning and weaving performance level, our PC-PROGRAM is must for all spinning mills.

For further information PROCESS OPTIMIZATION AND R&D PROJECTS FOR SPINNING MILLS

ITRU GROUP LTD -International Textile Research Unit

Serving to textile industry ,science and technology since 1992