Screen Printing Screen Making Procedure

Screen management (grinding, degreasing)

In order to combine the film with the screen Hollywood, the new screen must be grinded with a gauze paste. Each screen plate is completely degreased with a degreaser. The operation is to wet the screen surface with water, apply a grind or Degreasing agent, (also can use TPO screen base treatment agent) brushing with a nylon brush evenly and let stand for half a minute, and finally rinse with water.

Coating and drying

The sensitized glue is poured into the sizing device, which accounts for about half of the sizing device. The screen plate is tilted by 70 degrees, and it is firmly placed. The sizing blade comes into contact with the lower end of the screen, allowing the latex to flow onto the surface of the screen, and the sizing device slowly pulls it toward the top of the screen to uniformly apply it along the screen. Apply 3-4 coats on the surface first (take 270 mesh polyester mesh for example, put it in an oven for 10-15 minutes, remove it after it is completely dry, apply 3-4 coats on the surface and squeegee, and perform the second After drying for 10-15 minutes, it can be exposed after being thoroughly dried, and the drying temperature is controlled to be plus or minus 2 at 40 degrees Celsius.

exposure

The photosensitive adhesive absorbs wavelengths in the range of 2. 8-450mm and has a maximum absorption peak of 380mm. The light source and exposure time can be referred to the following table--parameters:

Light Source Power (W) Distance (M) Exposure time (seconds)
Metal halide table lamp (iodine lamp) 300 0.8 40-90
Diazo lamp 200 0.2-0.3 120-240
Ordinary fluorescent lamp 400-800 0.2-0.3 300-480

The parameters above are based on the 120T white screen. If other types of screens are used, the following percentages must be calculated:

·Dyeing screen (yellow screen) +30%

· Finer mesh than 130T - (10-25%)

· Thicker mesh than 100T + (10-50%)

When determining the exposure time, be sure to consider the length of time the light source is used. The performance of the light source has a great influence on the length of the exposure time. If the actual use time exceeds the effective life, the exposure time is extended accordingly.

development

Before developing, wet the screen with water on both sides and wait for about 30 seconds (be careful not to light). After the unexposed part of the squeegee has risen, rinse it with strong pressure and develop it. If the image on the screen cannot be fully displayed, the oven temperature is too high, the screen is overexposed, or it has been inadvertently exposed before processing.

Revision

Photosensitive adhesive or sealant can be used to make up the pectoral part of the eye and other unwanted parts (water-based screen can also use TPO edge sealing adhesive).

Hardening

In order to make the film fully cured, improve the printing rate, you can use direct sunlight for 1-2 hours or use the drying machine again exposed for 10 minutes, hardening treatment. Use paint printing as above.

If you use reactive dye disperse dye printing, it is recommended to use guard net water (hardener) or A + B hardening. Use a brush or sponge to protect the net water on both sides of the screen, and then stand for a few minutes, up to no more than 10 minutes. Use a vacuum pump to suck in excess netting water (pattern part) to avoid blocking the mesh. Place the screen in the oven (temperature not less than 40 degrees Celsius) and dry thoroughly.

Stripping

Apply the used printing plate to the appropriate solvent to remove the residual ink, and then use a yarn surface or sponge to take the stripping solution. Spread evenly on both sides of the plate. Allow it to react for about 1-2 minutes, then rub it with gauze or sponge. Can be stripped.

Closure

1. On the same screen, temporarily unprinted graphics or characters will be sealed with sealer and can be used after drying.
2, when you need to cover the graphics or characters, you must wash the printed material, use water to wash the graphics or characters can be restored, and then dry the screen can be used.

Photosensitive adhesive preparation

The method is as follows: "take 3-10 grams of photosensitizer (import 3 grams, domestic 10 grams) completely dissolved with 50 milliliters or water, add 950 grams of glue and stir to complete the glue, the glue with the work table at least two hours before , It is best to use glue one night before the next day.Do not use metal products to stir, so as not to affect the stability, photosensitizer should be stored at low temperature and light, glue storage should not be less than 5 degrees Celsius.