Pinholes are a general term for micropores on the screen surface. It can produce the disadvantages of printing stickiness, local ink layer deposition and thinning. Because the photoresist is uneven on the screen surface, the gradation printing becomes more unstable, the color difference is more obvious, and the service life of the screen is greatly reduced.

Analyze the causes of pinholes and take countermeasures in the whole process of screen making, which will greatly improve the quality of screens.

Pinholes appear on the screen during development, often caused by the following reasons:

(1) Incorrect screen degreasing.

(2) Degreasing residues remain on the screen before drying.

(3) Incorrect drying method after coating of photosensitive paste

(4) Incorrect drying method after coating of photosensitive paste

(5) When the screen is dry, put the screen with the displayed screen or degreased screen

(6) Screen is exposed before it is completely dry

(7) Dust and dirt are stuck on the printing film

(8)Dust stuck to the glass of the platform

(9) Dust particles in the indoor air of plate-making land on the surface of the photosensitive adhesive

 (10) Dust is stained in the plastic bucket

(11) Incorrect coating speed

(12) The mixing method of latex and diazo sensitizer is incorrect

(13) The sensitized photoresist has been left for too long

(14) The water source is not clean enough