How to Reduce Hard Waste in Weaving: A Proven Case Study
Abdulwahid Dadhiwale
DKTE Society’s Textile and Engineering Institute Ichalkaranji
Email: [email protected]
What Is Sale Yarn in Weaving?
Sale yarn, a common term used for hard waste in weaving, is a major hindrance towards yarn realization. In practice, the fastest gains come from tracking sale yarn sort wise, because one common pool hides the problem lot.
Sale yarn (hard-waste) minimization is the application of a systematic approach to reduce the generation of waste at source. Waste minimization applies to hazardous materials, non-hazardous materials, water, energy, raw materials, etc. Sale yarn as per terminology used in textile industry, is a kind of hard waste, obtained from weaving and preparatory department, which is sold at much cheaper price as compared to that of actual production cost. A mill should also keep sale yarn separate from soft waste, since the resale route and the corrective action are not the same.
Why Hard Waste Control Matters
Sale yarn is a direct loss to the industry. Waste minimization is important because it reduces operating costs, risk of liability, improves process efficiency, enhances public image, protects health and environment and improves employee’s moral. Waste is not only materials that are excess to requirements, but represents a loss of company profits.For a medium sized mill, which consumes about 10,000 kg of yarn per day, the financial gain from saving even 1% hard waste will range from about Rs 1.46 crore to Rs 2.19 crore per annum at current Indian yarn market quotations, according to Fibre2Fashion market listings, 2024 depending upon the average count. This is a retained material value estimate, so the net saving will depend on the resale rate of sale yarn. This justifies vigorous effort required to minimize hard waste. Control of sale yarn (hard-waste) is an essential step in minimizing the manufacturing cost.
Types of Waste in Weaving
In any section of the weaving department, a certain amount of waste will have to be incurred during the processing of the material. This waste can be divided into two types, Process waste and Incidental waste. The quickest reduction usually comes from identifying which part of the waste is process related and which part is avoidable shop floor loss.
1. Process waste:
It is unavoidable waste that has to be incurred to carry out operation and cannot be reduced to zero. This kind of waste largely depends on the nature of the operation and the type of equipments that are available. For example, some yarn is wasted when yarn from one package is knotted to that of another. This is where better machine setting and operator practice help, but they can never remove the waste fully.
2. Incidental waste:
All the remaining waste, which is not associated with any operation, will be referred to as incidental waste. This includes the waste that result from package fault like slough off, cuts, entanglement, etc. The percentage of waste depends upon some factors such as length of yarn on package from winding to weaving, count of yarn, end breakages at winding, weft breakages in loom shed, work practice and material handling. Humidity control and careful package handling are usually the first places to check when incidental waste stays high.
Case Study: Sale Yarn Reduction in a Textile Mill
The study has been conducted in a textile industry, which has a diverse product range of nearly 20,000 varieties of worsted suiting to cater to its customers across age groups, occasions, and styles. They said industry manufactures the finest wool-blended worsted suiting to speciality ring denims as well as high value shirting. As the product range is diverse to a larger extent, it has great impact on the amount of waste generated during the production process. This article discusses a case study that has already been implemented successfully in waste minimization program. Where the product mix is this wide, the first priority is usually the top five sorts that create the maximum sale yarn, because that gives a faster result than trying to change everything at once. The techniques used and the savings obtained will be highlighted here.
Sale yarn — Hard-waste as per terminology used in industry, obtained from weaving and preparatory department, which is sold at much cheaper price as compared to that of actual production cost. The exact resale value depends on the fibre mix, contamination level, and whether the waste is count specific.
Process Flow of Sale Yarn Control
The flow chart should move from sort identification to mending package preparation, then to loom shed issue, balance return, and sale yarn segregation.
Flow Chart of Process
Winding
↓
Warping
↓
Drawing-in
↓
Weaving
↓
In weaving of particular sort, extra warp package of same sort to mend end breaks is required. After completion of weaving this residual yarn on package is of no use as it does not have any identification and it is sent to the stock of sale yarn thereby creating huge sale yarn every month. Sale yarn is nothing but direct loss to the industry. This problem reduces sharply when the package carries the sort number and exact weight on a label that the loom shed can verify quickly.
Objectives of Waste Minimization
- Reduce operating costs and risk of liability.
- Improve process efficiency and employee moral.
- Enhance public image.
- Protect health and environment.
Methodology: How the Mill Reduced Hard Waste
Several studies have been conducted in the loom shed to determine exact amount of yarn required for individual sort for mending all end breakages that can occur during weaving. To find out this exact amount of yarn, a number of end breakage studies have been taken for all major sorts at different time intervals. A list of packages with their exact yarn content for each individual sort was prepared and same instructions were passed on to the re-winding in-charge & winders. The winders started preparing packages for mending end breakages as per the list and delivered to the loom-shed department with the beam of same sort. The sale yarn data for last six month was considered for the study. The issue register should carry sort name, package weight, date of issue, and balance returned. Without that record, the same mending package can be over issued very easily.
1. Production per loom according to sort
The sort wise output should be compared on the same loom and the same shift pattern, otherwise the waste picture becomes distorted.
2. Mending yarn required
According to previous study, for 85.34 mts fabric approximately 15 end breaks occur. Thus for full beam of 2500 mts approximately 440 end breaks will occur. For mending single-end break approximately one metre of yarn is required. Thus for complete beam approximately 440 mts of yarn would be required.
But other factors affecting length of yarn required for mending the end breakages are;
- Presence of missing end in the weavers beam.
- Condition of loom.
- Speed of loom.
- Relative humidity.
- Work practices of weavers.
After considering all above factors that may affect this calculated length of yarn,
The total length of yarn required for full beam would be = 940 metres.
(As packages deliver from rewinding to the loom shed in terms of their weight, so in terms of weight unit).
Metric count = Length in 1000 metre / Weight in grams
35 = 90/1000
= 33 grams only.
If beam length or loom speed changes, this figure should be rechecked instead of copied from an old study.
Package Weight for Mending Yarn
A list of package with the exact weight for common sorts produced in industry was prepared. Winders started to prepare packages for mending end breakages purpose as per the list given in Table 1. The beams delivered to the loom shed department with the warp package (for mending) of known weight as per the list. The package weight should be fixed sort wise and reviewed whenever the style changes.
Mending Package Size
Before study the package size for mending warp breaks at loom was 500 to 600gm . After study the package size reduced to nearly 1/10th ie, 50 to 80g. This type of packages is made on rewinding machine and the reduction works best when the returned balance yarn is checked at the end of every shift.
Graph Analysis
Graph represents relationship between gross weights of sale yarn in kg with time. X-bar represents time span of 5-days for which sale yarn is collected and Y-bar represents amount of sale yarn collected in kg. It is clearly seen from the graph, there is a gradual reduction in the amount of sale yarn after following the mentioned sort wise list of yarn package for the purpose of warp break mending. A weekly graph is useful only when the collection period stays the same, otherwise the trend becomes misleading.
Results: Sale Yarn Reduction
Before implementing this system the average mean of sale yarn collected per week was 11.56 kg and after implementation now it is 3.63 kg. Weekly saving of 7.93 kg has been achieved. That means an annual saving of 380.64 kg. Many mills also watch sale yarn per 1,000 metres of fabric, because it compares different sorts more fairly.
Annual Savings from Sale Yarn Reduction
Sale yarn contains all blends of yarn, as package that taken out of loom after weaving having no specifications regarding blend & material composition. The average production cost of all wool & 100% polyester yarn is around Rs 400 to Rs 600 per kg in current Indian market quotations for wool blended and polyester yarn, according to Fibre2Fashion market listings, 2024. That means an annual saving of Rs 1,33,224 even after deducting the profit after selling this waste. For current budgeting, mills should recalculate the net rupee saving with their latest inward price and sale yarn resale value.
Conclusion
The textile industry produces a wide variety of waste at all stages in the processing of fibres and fabrics. It is important to investigate all aspects of reduction in waste from the textile industry. This will reduce the cost of production and improve environmental performance. In order to achieve the above-mentioned advantages package must adhere to the standards laid down for mending of end breaks. The project guides textile industry in identifying areas of waste, constructing mass and energy balances, identifying suitable waste minimization options, determining the feasibility of implementation, and waste minimization makes good business sense. A simple sort wise mending register is usually the cheapest control tool in the loom shed.
Frequently Asked Questions (FAQs)
Q1. What is sale yarn in weaving?
Ans: Sale yarn is the hard waste left from weaving and preparatory operations. It is usually sold at a lower rate because it no longer has the original sort identification or full usable length.
Q2. How can hard waste in weaving be reduced?
Ans: The fastest method is to issue mending yarn sort wise, by exact weight, instead of using one common package for every loom. Regular loom shed checks, proper package labeling, and balance return control also cut waste quickly.
Q3. What causes sale yarn in a textile mill?
Ans: The main causes are end breakages, package faults, cuts, entanglement, slough off, poor material handling, and incorrect mending yarn issue. Humidity and loom condition also have a direct effect on the amount of waste.
Q4. Can sale yarn be reused in weaving?
Ans: In some cases, yes, but only if the yarn is identified correctly and kept sort wise. Once it loses traceability or becomes mixed contamination waste, it usually goes to sale yarn stock instead of being reused.
Q5. How do you calculate hard waste percentage in weaving?
Ans: Divide the weight of hard waste by the total yarn consumed, then multiply by 100. Mills often track this per loom, per sort, or per 1,000 metres of fabric so the figure is more useful for control.
References
- Process Control in Weaving by ATIRA.
- Paliwal & Radhkrishan: Process Control in Weaving.
- www.c2p2online.com/documents/Wasteminimisation-textiles.pdf.
- www.intota.com.
- www.abctextile.com/picanolloom.htm.
- www.fibre2fashion.com/industry-article/33/3206/waste-anagement-in-textile.
- Moin khan article on process control
Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. Mr. Kiron is working as a textile consultant in several local and international companies. He is also a contributor to Wikipedia.
