What should I do if there is white stain on the light guide plate printed by the printing machine?

It mainly depends on what kind of ink you use for screen printing.

The white stain you mentioned is usually caused by three aspects:

1. The surface of the acrylic plate is not clean (avoid touching it with your hands when tearing off the protective film of the acrylic plate) Touch it, it is best to tear off the protective film and screen-print it immediately);

2. The screen-printing tools are not clean, such as stencils, squeegees, etc. (To ensure the quality of the light guide plate, it is necessary to Before and after, the stencil and squeegee must be cleaned and stored in a place with little dust);

3. The ink is uneven (the ink must be stirred evenly before each use before screen printing can be performed) ;

Try again based on the above suggestions to see if there will still be any abnormal white stains. If it still occurs, then you can be sure that the screen has not been dried well, and the screen will be dry again ( It is recommended to use imported photosensitive adhesive for the stencil, which will have a longer life and fewer problems).