Rotary Screen Printing – Process, Machines & Profit Calculation

Introduction

Rotary screen printing is one of the most popular and widely used methods of textile printing in the modern garment industry. It is mainly used to print attractive designs, patterns, and colours on fabrics such as cotton, polyester, and blended fabrics. This method is especially popular in large-scale textile industries because it offers high production speed, good printing quality, and consistent results.

In simple words, rotary screen printing is a continuous printing process where fabric moves under rotating cylindrical screens, and different colours are printed onto the fabric at the same time.

1. Process of Rotary Screen Printing

Rotary screen printing involves several important steps. Each step plays an important role in achieving good printing quality.

Step 1: Fabric Preparation

First, the fabric is prepared for printing. It is cleaned and processed to remove dust, oil, wax, and other impurities. Proper fabric preparation helps the printing paste stick evenly to the fabric.

Step 2: Design Preparation

The required design is prepared using computer software. The design is separated according to different colours. Each colour needs a separate rotary screen.

Step 3: Screen Preparation

Cylindrical metal screens are prepared according to the design. Small holes are made in the screens to allow printing paste to pass through the required areas. Each screen is prepared for a particular colour.

Step 4: Printing Paste Preparation

Printing paste is prepared by mixing dyes or pigments with suitable chemicals, thickeners, and other required materials. The paste must have the correct thickness and consistency for smooth printing.

Step 5: Printing Operation

The prepared fabric moves continuously through the printing machine. The cylindrical screens rotate over the fabric, and printing paste passes through their small holes. In this way, different colours are printed on the fabric according to the design.

Step 6: Drying

After printing, the fabric passes through a drying chamber. This removes moisture from the fabric and prepares it for the next process.

Step 7: Fixation

The printed fabric is treated with suitable heat or steam, depending on the type of dye or pigment used. This helps the colour become permanent and improves colour fastness.

Step 8: Washing and Finishing

If required, the fabric is washed to remove extra printing chemicals and unfixed colour. Finally, it is dried, finished, inspected, and prepared for delivery.

2. Machines Used in Rotary Screen Printing

Different machines and equipment are used to complete the rotary screen printing process.

1. Rotary Screen Printing Machine: The main machine used to print designs continuously on fabric. It contains rotating cylindrical screens.
2. Fabric Feeding Unit: It feeds the fabric smoothly into the printing machine and maintains proper fabric movement.
3. Rotary Screens: These are cylindrical screens used to transfer different colours and designs onto the fabric.
4. Printing Paste Mixing Machine: It mixes dyes, pigments, thickeners, and other chemicals to prepare printing paste.
5. Drying Machine: It removes moisture from the printed fabric after printing.
6. Steaming Machine: It helps fix the colours onto the fabric when the printing process requires steaming.
7. Washing Machine: It removes excess printing paste and unfixed chemicals from the fabric.
8. Finishing Machine: It improves the final appearance, handle, and quality of the printed fabric.

3. Profit Calculation of Rotary Screen Printing

Profit calculation is very important for a textile printing factory. It helps the factory understand its production cost, selling price, and actual profit.

The total production cost includes fabric cost, printing chemicals, dyes, labour, electricity, machine maintenance, and other expenses.

The basic formulas are:

Total Cost = Total Production Expenses

Total Revenue = Selling Price × Production Quantity

Profit = Total Revenue − Total Cost

Profit Percentage = (Profit ÷ Total Cost) × 100

Example of Profit Calculation

Suppose a textile factory prints 10,000 metres of fabric.

Particulars	Amount (BDT)
Fabric cost	500,000
Printing chemicals and dyes	100,000
Labour cost	40,000
Electricity cost	30,000
Machine maintenance	15,000
Other expenses	15,000
Total Cost	700,000

Now, suppose the factory sells the printed fabric at BDT 85 per metre.

Total Revenue:

10,000 × 85 = BDT 850,000

Total Profit:

850,000 − 700,000 = BDT 150,000

Profit Percentage:

(150,000 ÷ 700,000) × 100 = 21.43%

Therefore, the factory earns a profit of BDT 150,000, and the profit percentage is approximately 21.43% based on production cost.

Note: This is an illustrative example. Actual costs and profits depend on fabric quality, design complexity, production quantity, machine efficiency, energy prices, and market conditions.

4. Advantages of Rotary Screen Printing

Rotary screen printing offers several advantages in the textile industry.

• High Production Speed: It can print large quantities of fabric in a short time.
• Continuous Production: Fabric can move continuously through the machine.
• Good Printing Quality: It produces clear and attractive designs.
• Suitable for Bulk Production: It is ideal for large-scale textile industries.
• Multiple Colours: Different colours can be printed in one continuous operation.
• Consistent Results: It provides uniform printing quality when properly controlled.
• Less Manual Work: Most of the printing process is automated.

5. Disadvantages of Rotary Screen Printing

Despite its advantages, this method also has some limitations.

• High Initial Investment: Rotary screen printing machines are expensive.
• Screen Preparation Cost: Separate screens are required for different colours.
• Design Limitations: Very small design changes may require new screens.
• Chemical Consumption: It requires printing paste, dyes, and other chemicals.
• Maintenance Requirements: Regular machine maintenance is necessary.
• Not Ideal for Small Orders: The initial setup cost may make small production orders expensive.

Conclusion

Rotary screen printing is an important and efficient printing method in the textile industry. It is widely used because of its high production speed, continuous operation, and ability to produce attractive designs in large quantities. The process includes fabric preparation, design development, screen preparation, printing, drying, colour fixation, washing, and finishing.

Although the initial investment and maintenance costs are relatively high, rotary screen printing can be profitable for large-scale production. Proper machine operation, quality control, cost management, and production planning are essential for achieving better results and higher profits.