This program is for use on IBM-compatible PCs to compute important fibre parameters,index of irregularity at each stage of processing,curves for short fibre content percentage,mean fibre length for leading and trailing hooks and drawing actual and optimum DRAFT CURVE through" Knowledge Based Problem Analyses and Problem Solving Techniques"developed by ITRU GROUP LTD.
1.Purpose of the program
Spin Plan 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 & Evenness tester instruments to be more valuable to the spinning mills by determining short fibre content by fibre number, mean fibre length,index of irregularity,draft curve.
1.1 Fibre Hook Theory
It has been very well known that fibres leaving the carding machine are not straight and parallel. Fibres have some hooks at leading and trailing sides.
And if these hooks are not gently straightened could be broken and weak places occur in yarn. Trailing and leading hooks could be determined by Itru Fibre Tester UAK-1 instrument by measuring the slivers at trailing and leading sides. Trailing hooks are mainly due to the transfer between carding cylinder and doffer. Therefore,by checking the card web,card sliver and hooks one could achieve optimum card sliver. Our SPINNING MILL DATA BANK+TEXTILE TECHNOLOGY & SPECTROGRAM ANALYSES PC-PROGRAMS is very effective to minimize trailing and leading hooks in carding. These hooks could be minimized but could not be eliminated. For this purpose we have also developed TRANSFER FUNCTION AND DRAFTING WAVES IN CARDING PC-PROGRAM.
Fibres leaving the carding cylinder contains hooked fibres and if these hooks are not properly straightened in subsequent processes then yarn quality is deteriorated. The other important point is that the fibre breakage in carding. If the fibres mean length after 1st passage of drawing does not increase then it is evident that fibres are broken in carding. Faulty transfer between carding cylinder and doffer and fibre breakage cause high linear irregularity of CV% in carding sliver and represent a similar pattern of drafting waves in drafting. Therefore the card settings,relative speeds of taker-in,cylinder and doffer and selection of proper card wire determines the carding performance. The processes after carding straighten these trailing and leading hooks. But over stretching of fibres in drafting zones could weaken the fibres and fibres are broken at drafting. ITRU GROUP LTD. based upon the actual mill experience and practical results claim that leading and trailing hooks play an important role in determining the yarn quality and spinning performance as well percentage of combing noil.
1.2 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 paralellism. 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 lineer evenness CV% 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.
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.
2.0 DATA INPUT and OUTPUT
|Input||Output : Problem Analyses/Problem Solving|
3.0 PC-PROGRAM MILL TRIALS FOR PROCESSING ORGANIZATION
Ratch setting distances and break draft ratios,draft organizations have large influence on the yarn quality parameters. It is clear that from mill experience that CV% of linear irregularity in carding,combing,drawing roving could vary and low CV% values would not always lead to better quality of yarn and it is always tedious to follow up the experiments upto spinning to see the effects of changes made in previous processes. SPIN PLAN ITRU GROUP LTD has been developed through extensive research work carried out on many spinning mills as well as many research work by the other institutions for the last 40 years.This PC-program for use on IBM compatible PCs to compute
- Index of irregularity for each stage of processing
- Mean fibre length by fibre weight curve for leading and trailing hooks from the Itru Fibre Tester UAK-1 span-length values to determine the fibre orientation degree and fibre breakage
- Short fibre content curve for leading and trailing hooks to determine over-stretched fibres and unsuitable drafting conditions such as field of friction of drafting forces,ratch settings.
- The complete actual draft curve in accordance with the actual fibre length growth and linear irregularity at each stage of processing so that optimum spectrogram curves could be obtained at each stage. We call this parameters as DRAFT CV and draft lengths for each process. Optimum linear irregularity value at each stage of processing to achieve optimum quality of yarn according to the requirements of yarn quality as well as identifying faulty running section in spinning process.
3.0.1 Importance of Processing Organization for Optimum Quality of Yarn
The optimum processing organization would depend upon upon mainly two factors:
Spinning Data consists of
-Type of yarn manufacturing process
-Turns per cm
Fibre Data should be selected in accordance with Spinning Data for achieving optimum yarn quality with minimum manufacturing costs for this purpose we have developed Fibre Mix Selection PC-Program . Therefore,processing organization should be compatible with Fibre Data and Spinning Data. Second point is to have optimum processing organization according to existing raw material mix in the mill. According our experience carried out in different spinning mills having similar fibre data and spinning data would lead to have different quality of yarn parameters due to different processing organization. Processing organization consists of mainly draft organization which includes number of doubling,count fed,ratch setting distances etc. The usual procedure is to make a trial tests at each stage of processing and follow it up to yarn. However,this is rather tiresome and could also be influenced by the changes in raw material mix. Therefore,one has to decide required yarn quality parameters mainly evenness of mass and strength . For example if one needs 12 CV% in yarn evenness then this program determines the required CV% values in prior processes in order to achieve target CV% value in yarn.
The CV% values in carding,drawing and roving should not be high and too low but in accordance with the draft curve. This assumptions made by us prove experimental works carried out in draw frames in many mills that low CV% values would lead high CV% values in yarn. But manufacturing of a yarn with accordance with the draft curve one could see the required CV% value at each stage of processing.
3.0.2 Importance of Draft Curve and Draft Angle
It is clear from our research work in many spinning mills that ratch setting distances and draft geometry are determined by two conceptions:
a)If the fibres move in tufts than sliver extension theory
b)If the fibres are parallel then fibre-extension theory.
c)Combination of both case a and case b.
We have also found that setting of ratch distances according to our MASS SPECTROGRAM PC-PROGRAM is very effective. MASS SPECTROGRAM PC-PROGRAM draws the actual spectrogram curve according to given fibre properties and CV% of sliver. By comparison of these two curves we could determine the drafting waves,fibre breakage and optimum ratch setting distances and break draft ratios.
On the other hand Draft curve is a sign of complete spinning process any deviations from this curve shows a faulty running process. We have also observed that draft curve is also related to the strength variation in the yarn. There are many quality/process control procedures which have been practiced in spinning mills and they are filed in files and signed by several mill staff. Draft Zone setting Pc-program is useful to identify the faulty running process and for quality improvement better mill running performance. But there are also other tests should be carried out in the mill. Process/Quality control and assurance procedures could be divided into two sections.
a)Knowledge Based eliminates problems before they occur such as our Fibre Mix Selection Pc-program which predicts the yarn strength before yarn manufacturing.
b)Statistical Process Control corrects the problem on line or of line. For zero defect both systems are necessary.
But the main point in any spinning mill is to have continuos improvement in minimum manufacturing costs and optimum quality of products with zero defects. Within this in mind we have examined all the existing quality/process control procedures and developed step by step problem analyses/problem solving systems through tests carried out in spinning mills. All the tests carried out in spinning mill analyzed in systematic manner and problems are solved in correct manner. With this system the complete process is improved.Step by step quality improvement findings
- Frequency diagram of yarn tensile force test
- Problem: High strength variation and weak places
- Material Process
- Fibre Mix Selection PC-program Draft Zone Setting Pc-program
- Bale Management PC-program Twist variation Control Pc-program
- RKM CV% Control Pc-program
Therefore,with the aids of PC-programs and more detailed analyses of the tests one can could get more exact solutions to the problems.
As it was mentioned before draft curve shows us the faulty running process and the draft angle is a sign of the quality level of the spinning process.
Abnormal changes in the draft angle indicates the deviation from normal spinning process.
4.0 Increasing Production Levels at each stage of processing
With this pc-program it is possible to increase production levels from carding to ring frames up to 20 to 30 percent depending upon the existing draft organizations.
5.0 Spin plan as a R&D project
We carry out spin plan pc-program as a research and development project in spinning mills .
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