Flat Bed Screen Printing Chemicals
Under the Direct Emulsion Technique of stencil preparation Flat Bed Emulsion
is coated onto the screens and within no time screen is ready for printing and this replaces the traditional time consuming and irritating methods of preparing the screens. Our PHOTO EMULSION is manufactured under standard conditions and under strict quality control.
Procedure for Flatbad Screen Printing
Cleaning the Screen
Proper fabric treatment and adequate degreasing are very important for good result. Therefore, wash the screen with clean water and dry it.
Take 1 kg of Flat bed Emulsion in a clean vessel.Also take a glass of distilled water sufficient to mix 10.Grams.of Ammonium Dicromate (or our ready to use sensitizer) and stir the solution till it is completely dissolved. Mix this solution of Ammonium Dicromate with the Flat Bed Emulsion
solution of 1 kg. and stir until the colour of the solution is changed to light uniform green. Viscosity of the emulsion can be adjusted with distilled water. Filter the emulsion with bolting cloth and close the container at least for 1/2 hour so that all the air-bubbles are disappeared.
Processing and Coating Techniques
It is always desirable that light in the Photography department is subdued light and if possible, yellow light. Direct emulsion
Chemicals coating requires skill to produce uniform pinhole free stencils.
Important factors are the fabric mesh number, thread diameter, colour of the fabric, the tension and the solid contents, the thickness of the coating blade, angle and speed of the coating blade across the screens etc. If you change the supplier of the bolting cloth, check and see that you are receiving the same type of material as before. Thus it is very important that print quality is dependent upon the correct coating technique. If the coating is made to the satisfaction then one coating is sufficient from outside otherwise repeat the procedure.
After the coating is over, it is important to thoroughly dry the coated screen before it is exposed otherwise stencil quality will be poor. Moisture remains present in the coated screen even when the screen feels dry to touch if you are coating the screen for second
time Printing. It is important that the first coat be thoroughly dry before the second coat is applied. Dry the coated screens in horizontal position at room temperature with fans, to get best result and sharpness.
Exposing is one of the most important factors in achieving fine image and sharpness and maximum mechanical screen resistance. The only way of achieving the correct exposing is through adjusting exposing time using fixed factors such as no. of tube light, the quality of the light, set distance and set coating techniques and accordingly photography time is adjusted. Time of photography varies between 30 seconds to 120 seconds under standard conditions.
Immediately after the exposure of screen wash the screen with gentle spray of water from the squeeze side i.e. inside until the image comes up, if required use rubber foam gently.
Blocking out and touch up
The most common method is to use the excess emulsion for filling the entire screen with a piece of cardboard, if touching is required use the same material.
Drying with sensitizer
After the screen is washed out. dry the screen and apply with piece of cloth liquid solution of ammonium Di-cromate. Before sending it to printing department, wash the screen with a sprayer to remove the excess Di-cromate. Your screen is ready for printing.
Advantages in Flat Bad Screen Printing
Considerable time is saved in preparing one complete screen with Rung photo emulsion. The screen is ready to use within 30 to 45 minutes depending upon the repeat and urgency which otherwise take a day with lacquer.
Cost wise Rung emulsion is cheaper than the traditional lacquer which is very costly.
Printing program is not disturbed if screen is torn out on the table or machine. With Flat Bed
emulsion, Screens can be prepared immediately.
Sharpness of the design is the hallmark of the Flat Bed emulsion and sharpness of the design improves to a great extent.
Cleanliness in the photography department and avoidance of bad smell is possible with the use of Flat Bed emulsion.
NOT SENSITIZED 12 to 20 months ( 30’ C )
Keep the container closed & away from sunlight.
Shelf Life: 12 months, if container is properly closed.
Packing: 10 & 30 Kgs