Question

Explain the process for the following with its advantages and disadvantages :
(a) Hand Screen Printing
(b) Roller Printing

Hint:

Hand screen printing uses mesh screens and a squeegee; roller printing uses engraved copper rollers.

Answer 1

Step 1: (a) Hand screen printing: process:
A screen is a wooden or aluminium frame with a fine mesh of silk, nylon or polyester stretched tight.
The design is put on the mesh by a stencil or photographic method, and non-design areas are blocked with emulsion.
One screen is made for each colour in the design.
Fabric is fixed flat on a long padded table. The screen is placed on it, print paste is poured and a squeegee pulls the paste over the screen.
The paste passes through the open mesh onto the cloth. Each colour is printed after the earlier one has dried.
The cloth is finally dried, steamed or cured, and washed.

Step 2: Hand screen printing: advantages:
The set-up cost is low.
It suits short runs, large designs and many kinds of fabric.
It gives bright, solid colour and allows fine detail.
Design changes are easy.

Step 3: Hand screen printing: disadvantages:
It is slow and needs skilled labour.
Registration (matching screens) is difficult and may vary.
Output is low, so it is costly for bulk orders.

Step 4: (b) Roller printing: process:
Designs are engraved on copper rollers, one roller per colour.
Each roller touches a furnishing roller that picks colour paste from a trough. A steel doctor blade scrapes extra paste from the roller surface.
The cloth passes between the engraved roller and a large central cylinder covered with a blanket. Colour transfers under pressure.
The printed cloth is dried, steamed, washed and finished.

Step 5: Roller printing: advantages:
It is fast and has high production.
It is cheap per metre for long runs.
Prints are even and fine.

Step 6: Roller printing: disadvantages:
Engraving of rollers is very costly.
The repeat size is limited by the roller circumference.
Short runs are not economical, and design change is slow.
The machine is big and needs skilled handling.

Final Answer:
Hand screen printing is flexible and low cost but slow; roller printing is fast and economical for long runs but needs costly engraved rollers and limits repeat size.