Weaving Process in Textile:
Weaving is a process in which two sets of yarns are interlaced to form a fabric. The lengthwise set of yarn is called warp, and the widthwise yarn is called weft. To make fabric, the lengthwise yarn and the widthwise yarn have to be interlaced in such a way that the warp yarns pass under and over the weft yarns in a systematic order. Similarly, the weft passes under and over the warp yarns in a systematic order.
Weaving is a type of process that is used to manufacture the fabric by interlacement of warp and weft yarn by various types of weaving machines ranging from manual to fully automatic machines. The general process flow of the weaving process is depicted in below for simple understanding.
Receipt of warp yarn and warp knotting process in the loom
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Fabric formation by weft insertion
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Development of grey fabric
Though several types of weft insertion methods used in the weaving machine, it decides the amount of fabric produced per minute. The weft insertion speed decides the major cost and is based on the number of picks inserted in the warp yarn (that decides the amount of fabric produced) and the speed (RPM – Revolution per Minute) of the machine. The second most commonly influencing factor is the labor cost and then the factory efficiency.
Other important factors are the design or the fabric structure produced. Based on the style complications, the loom speed will reduce (efficiency) during the production. For example, a dobby design using more number of healds or higher warp yarn usage will lead to significantly less production. Similarly, the number of colors used in the weft also plays a role. As the normal weft insertion system has 2 – 4 colors as default, more number of colors in the weft will ultimately increase the cost of production as the productivity is less. Further, the pick insertion is also affected majorly when the designs like pile or extra warp threading designs are used.
Weaving Cost Calculation:
Weaving cost calculation involves estimating the total expense of producing woven fabric. It depends on several factors such as raw material costs, machine operation, labor, and overhead expenses.
Importantly, the cost of fabric produced by the weaving machine is measured with respect to the length of fabric produced, normally in cost/meter or cost per pick produced. The other factors are detailed as follows.
Factors Influencing the Weaving Cost:
Following are the factors which influences the weaving cost.
- Design complications like, dobby designs, top beam design, etc.
- Number of colors in warp and weft threads
- Machine width used
- Total number of machines used
- Number of shifts per day
- Production capacity of the plant or individual machine/shift or day
- Yarn quantity used
- Waste percentage
- Number of operators and helpers
- Operator wages
- Electricity bill and
- Other expenditures
Formula for Weaving Cost Calculation:
Formula used for calculation of weaving cost are,
…………………….(Yarn rate + Sizing cost) × Number of cord
1. Warp cost = ————————————————————————-
………………………….Length of yarn (840 × yarn count)
= Cost / yd
……………………Yarn rate × Fabric width × Gear number
2. Weft cost = —————————————————————
……………………….Length of yarn (840 × yarn count)
= Cost / yd
3. Miscellaneous = Weaving charge + Electricity + Maintenance
Hence,
Weaving cost / yd = Cost of warp yarn / yd + Cost of weft yarn / yd + Wastage + Miscellaneous.
The following example detail the cost calculation methods used in the total cost estimation and the cost/meter calculation in the weaving industry.
Example:
A weaving unit with auto looms received an order to produce 75,000 meters of plain-woven fabric. The loom shed consists of 40 looms with the capacity of 280 rpm. The company works with 12 weavers, 6 helpers with the salary of Tk.450 / shift and Tk.380 /shift respectively. The shed is maintained by 3 supervisors with a total salary of Tk.22,000 per month. If the company works with 65% efficiency and produces fabric with average 70 picks per inch, calculate the cost of weaving process per meter with 15% profit. The overhead details are Tk. 2,50,000/month for power, Tk. 1,00,000/month for other staff salary, Oil and other consumables are Tk.70,000/month. For spares and maintenance, company spends Rs 80,000/month and Rs 25,000/month for drawing, denting and knotting cost. Also, Tk. 3,00,000 as other expenses and bank interest due is incurred. Assume company works 30 days per month and 3 shifts per day.
Solution:
The total production needs to be done = 75,000 meters
Step 1: Production shifts required
The daily production of the shed can be calculated as follows,
………………………………………………R.P.M
Production per machine = ———————————× 60 (min/hour) × 24 (working hrs/day)
…………………………………….Picks per inch × 39.37
……….280
= ———————– × 60 × 24
….70 × 39.37
= 146.30 metres / machine / day at 100% efficiency
Production at 65% efficiency = 146.3 × 0.65 = 95.095metres / machine / day
Total production / day = 40 × 95.095= 3,803.8 meters / day
Hence, to complete the current order,
…………………………………………………………Order quantity
The total number of days required is = ———————————-
……………………………………………………….Daily production
…..75,000
= —————–
….3,803.8
= 19.72 days
As company works 3 shifts / day, total number of shifts are = 19.72 × 3 = 59.16 shifts
Step 2: Labor cost
The number of labors used are12 machine weavers with the wage of Tk. 450/shift, 6 machine helper with the wage of Tk. 380/shift and 3 supervisors with the salary of Tk. 22,000/month.
The supervisor wage per day = 22000/30 = Tk.733.33
Hence, the total labor cost is
= (Number of labors × Total working shifts × Wages per shift)
For weavers = 12 × 59.16 × Tk. 450 = Tk. 3,19,464
For helpers = 6 × 59.16 × Tk. 380 = Tk.1,34,884.8
For supervisor = 3 × 19.72* × Tk.733.33 = Tk. 43,383.80
Total labor cost = Tk.4,97,732.60
Step 3: Overhead charges
Tk. 2,50,000 / month for power,
Tk. 1,00,000 / month for other staff salary,
Tk.70,000 / month for oil and other consumables
Tk. 80,000/ month for spares and other parts
Rs 25,000 / month as knotting cost
Tk.3,00,000 / month as other expenses
Total overhead expenses = Tk. 8,25,000
Since, the factory works 30 days in a month,
……………………………………………..8,25,000
The daily overhead expense is = ——————–
…………………………………………………30
= 27,500
Total working days = 27,500 × 19.72 = Tk.5,42,300
Step 4: Total weaving cost
Total cost = labor cost + overheads = Tk.4,97,732.60 + Tk.5,42,300
= Tk. 10,40,032.6
Hence, Weaving cost/meter = 10,40,032.6 / 75000
= Tk. 13.87/meter
Weaving cost with 15% profit = 13.87+ {(13.87 × (15/100 )}
= Tk. 15.95/meter fabric
*Note: Here, the supervisors alone work in a monthly salary basis, hence, for them the number of days is considered for cost calculation instead of shifts
References:
- Handbook of Textile and Apparel Costing by Dr. R. Rathinamoorthy, Dr. R. Surjit and Dr. K. J.Vishnu Vardhini
- Fabric Manufacturing Technology: Weaving and Knitting by K. Thangamani and S. Sundaresan
- Apparel Merchandising by R. Rathinamoorthy and R. Surjit
- Handbook on Fabric Manufacturing: Grey Fabrics: Preparation, Weaving to Marketing by B. Purushothama
- Textile Engineering – An Introduction Edited by Yasir Nawab
