Monday, April 17, 2023

Table screen printing process

 Table screen printing process

The table screen printing method is widely used to print various types of fabric. Fabric is printed on the table that is why this method is called table printing. Flat screens are used in method therefore it is also called the table screen printing technique.

Advantages of table screen printing:

1- This fabric printing technique is a cost-effective technique. 

2- The design repeat size is bigger than any other fabric printing technique. 

3- The wastage of colours and fabric is very low. 

4- The edges sharpness of the design results is excellent. 

5-Minimum order quantity is very short. 

6- We can even print one meter of fabric sample in table screen printing.

7- The printed fabric is dried by sun drying therefore drying cost is very low.

Disadvantages of table screen printing technique:

1- The number of colours in table screen printing is limited.

2 - Almost 6 - 7 colours design can be printed by table screen printing.

3- The fitting accuracy of the colours in the printed fabric design gets low.

4- if continuous fabric or yardage is printed in the table screen printing, the repeat joining line may appear in the fabric.

5- It is labor intensive printing technique.

6- approximately, 30 - 35 meters of fabric can be printed on the table screen printing at a time on one table. 

7- The depth of the printed colour may slightly vary due to manual striping.

8 -  This printing technique has width limitations as well.

9- Productivity is low.

Table screen printing process:

The whole printing process gets completed in the below steps:

1- Screen preparation

2- Table preparation and setting

3- Fabric mounting upon the table

4-Colour preparation  and matching

5- Fabric printing

5- Fabric drying

6- Fabric curing 

7- Fabric checking and touching

8- Fabric folding and packing

Screen preparation:

Screen preparation is a very critical task in the table screen printing process. this task is performed by a well-trained person. The screen preparation takes place in the below steps.

  • The printer receives either printed fabric samples or artwork.
  • If he receives a printed fabric sample, the artwork is developed by the printer.
  • Now, the tracing of the each colour is prepared.
  • The tracing is prepared upon the transparant plastic sheet having good flexibility and strength.
  • The area having colour is painted with black colour in each tracing paper.
  • The blank area is left unpainted in the tracing paper.
  • Now, blank screens are prepared.
  • Very fine and perforated polyester fabric is is mounted on the round pipes square or rectangular iron frame securely and tightly.
  • One blank screen is prepared for each colour.
  • Now all these screens are coated with photo emulsion and dried well under sunlight.
  • Now, these photo emulsion coated screens are exposed to high intensity light as per tracing.
  • The tracing is placed over exposing table then the photo emulsion coated screen is placed over the tracing. Now, the photo emulsion coated screen is covered by plan metal or plywood sheet.
  • The exposing table light is switched on now for definite time.
  • Thanks the photo emulsion coated screen exposes with high intensity light. The light falls on those areas of screen directly where the blank area of the tracing allows to pass light. The areas exposed with High intensity light gets hardened. 
  • Now, these screens are washed in weather by high pressure water supply. The the hardened areas of photo emulsion in the screen remain fixed in the screen but unexposed areas of photo emulsion with light get washed out and the photo emulsion is removed. 
  • Now, each screen is checked. If required, touching of photo emulsion is done on damaged areas.
  • Thus, the all screens get ready for use.

Printing table preparation and setting:

  • Two types of printing tables are used in table screen printing.
  • Cushioned (bed type) table is used in some printing unit while adhesive bonded tables are used in the other Printing units.
  • In the cushioned (bed type) printing table, few layes of fabric are spread out over the printing surface of the table.
  • In the adhesive bonded table, the top surface of the printing table is covered with good quality non woven bonded cloth made of synthetic fibres.
  • A layer of adhesive is coated upon the top surface of this table.
  • In case of adhesive coated table, it is washed thoroughly before start printing.
  • The screen positioning elements are fixed as per design properly. 
Fabric mounting upon the printing table:

  • Now the fabric is mounted upon the printing table.
  • In case of cushioned (bed type) printing table, the fabric is fixed with the help of steel pins. 
  • The steel pins hold the fabric at the both selvedge.
  • In case of adhesive coated printing table, the fabric gets stup upon the printing surface due to adhesive coating upon the surface.
  • The fabric is mounted straight.
  • The wrinkle free fabric mounting is assured.
  • The fabric is mounted tightly in the both directions.
  • The side margin in the table is kept as per fixation of screen positioning elements.
  • Thus, the fabric gets ready for Printing.

Colour preparation and colour matching:
  • The colours paste is prepared in the colour kitchen.
  • Each colour is prepared separately and as per colour recipes.
  • A band of fabric in each colour is printed in each colour till proper matching achieved.
  • Now, our colours pastes get ready for use.

Fabric printing:
  • Each colour is printed one by one.
  • Lightest colour is printed first.
  • The darkest colour is printed at the last.
  • Printing starts from one end of the fabric and finishes at the other end of the fabric.
  • The screen is placed over the fabric and is aligned with the help of screen positioning element.
  • Now, the colours paste is dropped at the one side of screen.
  • The colour paste is wiped out from one to other side of the screen. The colour paste penetrated through the fine holes of the screen and gets stuck upon the fabric.
  • Now, other colours are also printed in the same way.

Fabric drying:

  • If the steam heated table is used, the the fabric gets dried after my some time and it was s taken out from the printing table.
  • In case of cold table printed fabric is left for drying by natural moisture evaporation.
  • Ceiling fans air helps to accelerate the speed of drying there.
  • After some time, the fabric is taken out from the table and is hung upon strings tied in the walls of the shed for further drying.
Fabric curing:
  • This printed fabric does not show proper colour fastness.
  • This fabric is passed through a heating chamber where hot air blows.
  • The polymerization process takes place and the colour fastness gets improved.
Fabric checking and touching:

  • Now the fabric is checked for any printing defect.
  • If any unprinted area appears after printing, the colour is painted by touching brush or pen .

Fabric folding and packing:

  • Now, the fabric length is measured and rolling if the fabric is carried out.
  • The rolled fabric is packed in the polythene sheet and then in hussian cloth .
  • Thus printing fabric gets ready for dispatch.

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