Bleaching Process in Textile:
Cost calculation for bleached fabric involves several steps, considering various factors like raw material costs, process expenses, and overheads. Bleaching is an essential pre-process in the fabric dyeing activity. Bleaching process is a critical step in textile wet processing aimed at improving the whiteness and brightness of fabrics by removing natural or synthetic impurities, such as oils, waxes, and color pigments.
The main aim of the bleaching is to remove the coloring matters present in the fabric after the scouring process. In this process, the fabric is passed through the bleaching agent, either oxidative or reductive type of bleaching agents and washed subsequently to obtain the colorless fabric. In this process also, several chemicals are used along with the bleaching agent to achieve higher whiteness index value. This whiteness will improve the dyeing ability of the fabric in the subsequent process. By bleaching process increasing high and uniform absorptivity of fabric for water, dyestuffs and finishing agent, achieved by the removal of hydrophobic impurities from the natural fibre.
The process sequence of the bleaching process is provided below.
Fabric feed from singeing process
↓
Chemical feeding system
↓
Desaizing unit for desizing process
↓
Squeezing mangle
↓
Batching or storing unit
↓
Fabric plaiting unit
Factors Influencing in Cost Calculation for Bleached Fabric:
In bleaching process, bleaching chemical is used as the main agent to remove the color along with other auxiliary chemicals to improve performance. In this process, the following are the parameters influence the cost calculation for bleached fabric.
- Machine production speed
- Chemical cost
- Labor cost
- Steam cost (used in squeezing mangle and drying cylinders)
- Factory efficiency
- Electricity cost
- Water cost
- Other overhead expenses
Example: 1
A processing mill received an order from the garment manufacturer to bleach a knitted fabric of 2,800 kg. In this process, the processing industry must desize, scour and bleach the fabric. For this process, the average daily production of the continuous bleaching range machine is 160 kg/day. The company works with 4 such machines for this order. The material and the prices used in the process are listed below in Table 1. To complete the order, the factory works with 6 machine operators, and 5 helpers with a wage of Tk.780/shift and Tk.620/shift respectively. Calculate the bleaching cost per kg with 10 % profit, if the company works two shifts per day. The overhead expenses are estimated as follows. Factory rent – Tk.45,000/month, effluent treatment expenses Tk.55,000/month, other staff salary – Tk.18,000/month, steam expenses – Tk.35,000/month and other overheads like maintenance, etc. – Tk.50,000/month of 30 days.
Table 1: Raw materials used and their prices
| S.No | Chemicals used | Cost in Tk./kg | Total quantity in kg |
| For desizing | |||
| 1 | Desizing agent | 95 | 110 |
| 2 | Wetting agent | 50 | 40 |
| 3 | Alkali | 60 | 65 |
| For scouring | |||
| 4 | Concentrated alkali | 70 | 95 |
| 5 | Wetting agent | 50 | 40 |
| 6 | Neutralising agent | 75 | 75 |
| For bleaching | |||
| 7 | Bleaching agent | 160 | 88 |
| 8 | Alkali | 60 | 65 |
| 9 | Dispersion agent | 50 | 125 |
| 10 | Stabilising agent | 100 | 20 |
Solution:
Step 1: Number of shifts required
The total production needs to be done = 2800 kg
Daily production of the company = 160 kg/day/machine
Total production capacity = 160 × 4 = 640 kg/day
…………………………………………………Order quantity
Hence, the total shifts required = ——————————-
……………………………………………….Daily production
…2,800
= ————-
….640
= 4.375 days
Company works 2 shifts per day. Total shifts = 8.75 shifts.
Step 2: Labor cost
To complete the order, the factory works with 6 machine operators, and 5 helpers with a wage of Tk.780 and Tk.620 respectively.
Hence, the total labor cost is
= (Number of labors × Total working shifts × Wages per shift)
= (6 × 8.75 × 780) + (5 × 8.75 × 620)
= Tk.40,950 + Tk.27,125
= Tk. 68,075
Total Labor cost = Tk. 68,075
Step 3: Calculation of raw material cost
Table: 2 Raw material cost calculation
| S.No | Chemicals used | Cost in Tk./kg | Total quantity in kg | Total cost in Tk. |
| For desizing | ||||
| 1 | Desizing agent | 95 | 110 | 10,450 |
| 2 | Wetting agent | 50 | 40 | 2,000 |
| 3 | Alkali | 60 | 65 | 3,900 |
| For scouring | ||||
| 4 | Concentrated alkali | 70 | 95 | 6,650 |
| 5 | Wetting agent | 50 | 40 | 2,000 |
| 6 | Neutralising agent | 75 | 75 | 5,625 |
| For bleaching | ||||
| 7 | Bleaching agent | 160 | 88 | 14,080 |
| 8 | Alkali | 60 | 65 | 3,900 |
| 9 | Dispersion agent | 50 | 125 | 6,250 |
| 10 | Stabilising agent | 100 | 20 | 2000 |
| Total raw material cost | 56855 | |||
Step 4: Overhead cost
Factory rent – Tk.45,000/month,
Effluent treatment expenses Tk.55,000/month,
Other staff salary – Tk.18,000/month,
Steam expenses – Tk.35,000/month
Maintenance of machine – Tk.50,000/month
Total overhead expense Tk.2,03,000
Company works for this order only 4.375 days.
……………………….2,03,000
Overhead/day = ——————
………………………….30
= Tk. 6,766.67
Therefore, 6,766.67 × 4.375 = Tk. 29,604.18
Step 5: Total cost of the dyeing
Total cost = Labor cost + Material cost + Overheads
= Tk. 68,075+ Tk. 56,855+ Tk. 29,604.18
= Tk. 1,54,534.18
…………………………………1,54,534.18
Total dyeing cost / Kg = ——————-
……………………………………2,800
= Tk. 55.19
Profit 10% = Tk. 55.19 + {Tk. 55.19 × 0.10} = Tk. 60.71
Example: 2
A processing unit received an order of 6,200 kg of knitted fabric to singe and bleach subsequently. In this process, the factory runs a singeing machine with a production capacity of 820 kg per shift. The machine is operated by 2 operators with a wage of Tk.720/shift. The gas expense for the process is noted as Tk. 2,000/shift. Similarly, the factory runs two desizing machine with a production capacity of 280 kg/shift per machine. The machine is operated by 5 operators and 3 helpers with a wage of Tk.800 and Tk. 610 per shift. The chemicals used in the process and its prices are listed below in Table 3.
Calculate the bleaching cost per kg with 20 % profit, if the company works two shifts per day. The overhead expenses are estimated as follows. Power –Tk.80,000, firewood – Tk.8,000/shift of fabric processed, effluent treatment expenses Tk.50,000/month, factory manager salary – Tk.42,000/month and other overheads like maintenance, etc. – Tk.30,000/month of 30 days.
Table 3: Raw materials prices
| S.No. | Chemicals used | Cost in Tk./kg | Actual consumption |
| For desizing | |||
| 1 | Desizing agent | 120 | 85 |
| 2 | Wetting agent | 85 | 60 |
| 3 | Alkali | 60 | 65 |
| For scouring | |||
| 4 | Concentrated alkali | 100 | 120 |
| 5 | Wetting agent | 85 | 90 |
| 6 | Neutralizing agent | 65 | 80 |
| For bleaching | |||
| 7 | Bleaching agent | 140 | 180 |
| 8 | Alkali | 60 | 75 |
| 9 | Dispersion agent | 65 | 85 |
| 10 | Stabilizing agent | 100 | 40 |
Solution:
Singeing cost calculation
Step 1: Number of shifts required
The total production needs to be done = 6,200 kg
Daily production of the company = 820 kg/shift/machine
………………………………………………..Order quantity
Hence, the total shifts required = ——————————
……………………………………………….Daily production
…6,200
= ———-
….820
= 7.56 shifts
Step 2: Labor cost
To complete the order, the factory works with 2 machine operators with a wage of Tk.720 / shift.
Hence, the total labor cost is = (Number of labors × Total working shifts × Wages per shift)
= (2 × 7.56 × 720)
= Tk. 10,886.4
Total Labor cost = Tk. 10886.4
Step 3: Overhead cost
Gas expenses for singeing process
= Tk. 2,000/ shift processed
= 7.56 shifts × 2,000 Tk./shift
Total overhead expense = Tk.15120
Step 4: Total cost
Total cost = Labor cost + Overheads
= Tk. 10,886.40 + Tk.15,120
= Tk. 26,006.4
…………………………………….26,006.4
Total singeing cost / Kg = ——————
………………………………………6,200
= Tk. 4.19
Desizing and bleaching cost calculations
Step 1: Number of shifts required
The total production needs to be done = 6,200 kg
Daily production of the company = 280 kg/shift/machine
Total production capacity = 280 × 2 =560 kg/Shift
………………………………………………..Order quantity
Hence, the total shifts required = ——————————–
……………………………………………….Daily production
…6,200
= ————-
….560
= 11.07 shifts
Company works two shifts per day. Hence, total days = 3.69 days
Step 2: Labor cost
To complete the order, the machine operated by 5 operators and 3 helpers with a wage of Tk.800 and Tk.610 per shift.
Hence, the total labor cost is
= (Number of labors × Total working shifts × Wages per shift)
= (5 × 11.07 × 800) + (3 × 11.07 × 610)
= Tk.44,280 + Tk.20,258.10
= Tk. 64,538.10
Total Labor cost = Tk. 64,538.10
Step 3: Calculation of raw material cost
Table 4: Raw materials expense details
| S.No. | Chemicals used | Cost in Tk./kg | Actual consumption | Total cost in Tk. |
| For desizing | ||||
| 1 | Desizing agent | 120 | 85 | 10,200 |
| 2 | Wetting agent | 85 | 60 | 5,100 |
| 3 | Alkali | 60 | 65 | 3,900 |
| For scouring | ||||
| 4 | Concentrated alkali | 100 | 120 | 12,000 |
| 5 | Wetting agent | 85 | 90 | 7,650 |
| 6 | Neutralizing agent | 65 | 80 | 5,200 |
| For bleaching | ||||
| 7 | Bleaching agent | 140 | 180 | 25,200 |
| 8 | Alkali | 60 | 75 | 4,500 |
| 9 | Dispersion agent | 65 | 85 | 5,525 |
| 10 | Stabilizing agent | 100 | 40 | 4,000 |
| Total raw material cost | 83,275 | |||
Step 4: Overhead cost
- Power – Tk.80,000
- Effluent treatment expenses Tk.50,000/month,
- Factory manager salary – Tk.42,000/month
- Other overheads like maintenance and etc – Tk.30,000/month
- Firewood – Tk.8,000/shift of fabric processed = 8,000 × 11.07 = Tk. 88,560
Total overhead cost = Tk. 2,02,000 (Except Firewood cost)
Company works for this order only 5.54 days.
……………………….2,02,000
Overhead/day = ———————-
…………………………..30
= Tk. 6,733.33
Therefore, Tk.6,733.33 × 11.07
= Tk. 37,302.67
Total Overhead expense = Tk. 37,302.67 + Tk. 88,560 (Along with firewood cost)
= Tk. 1,25,862.67
Step 5: Total cost of the Bleaching
Total cost = Labor cost + Material cost + Overheads
= Tk. 64,538.10 + Tk.83,275+ Tk. 1,25,862.67
= Tk. 2,73,675.77
………………………………………2,73,675.77
Total bleaching cost / Kg = ———————–
…………………………………………6,200
= Tk. 44.14
Hence the total fabric cost = Singeing cost/kg + Bleaching cost/kg
= Tk.4.17 + Tk. 44.14
= Tk. 48.31 Profit 20%
= Tk. 48.31 + {Tk. 48.31 × 0.20}
= Tk. 57.972
Conclusion:
Cost calculation for bleached fabric production involves assessing raw material costs, process expenses, overheads, and additional factors like packaging and transportation. Accurate costing is crucial for setting competitive prices and maintaining profitability while ensuring quality. Optimizing raw material usage, enhancing production efficiency, reducing energy consumption, and managing waste effectively are key strategies to minimize costs. By continuously refining these processes, manufacturers can improve operational efficiency, meet market demands, and sustain a competitive edge.
References:
[1] Rathinamoorthy, R., Surjit, R., & Vardhini, K. J. V. (2024). Handbook of Textile and Apparel Costing. https://doi.org/10.1201/9781032629896
[2] Rathinamoorthy, R., & Surjit, R. (2017). Apparel Merchandising. In WPI Publishing eBooks. https://doi.org/10.1201/9780429505737
[3] Sinclair, R. (2015). Textiles and fashion : materials, design and technology. In Woodhead Publishing
[4] Kolanjikombil, M. (2019). Pretreatment of textile substrates. Woodhead Publishing.
