Graphic silk screen print pattern is exquisite, but there are often some quality defects such as color difference, lack of ink, and bottom leakage. How effectively detect silk screen pattern quality? Not necessarily, but a reasonable screen print pattern examination condition may be:
1. Luminosity: 200-300LX (equivalent to 40W fluorescent lamp, distance of 750mm from the lamp to screen printed object)
2. The surface of the product to be inspected about 45° from the inspector’s visual direction to observation.
3. The distance between the inspector’s visual and the surface of the printed pattern to be inspected is from 400mm~800mm.
Now, what are the common defects?
1. Foreign matter: dust, dots, or filaments are attached to the pattern.
2. Exposed bottom: Because the silk screen printing position is too shallow to expose the bottom color.
3. Missing print: The pattern required screen printing position is not covered.
4. Fuzzy and broken lines; Poor quality screen print net causes uneven thickness of lines and patterns, blurred, and partially disconnected lines.
5. Uneven thickness of screen print: improper operation of screen printing, the thickness of the screen printing layer of dot lines or patterns is uneven.
6. Dislocation: An inaccurate position of the screen leads to the patterns offset.
7. Poor adhesion: The adhesion of the screen coating is not enough, and it can be rubbed off easily.
8. Pinholes: pinholes can be seen on the surface of the coating film.
9. Scratches: poor protection after screen print pattern
10. Variety or stain: colors other than pattern color adhered.
11. Color difference: Compared with the standard color plate code, the color has deviation.
