- Fine line printing of screen printing -
How thin can screen printing be? You may be asked a question. A common answer is that it is not possible to print a fine pattern that is smaller than the thread diameter used for the screen mask. Indeed, the paste cannot pass through the threads of the screen mask. At first glance, it seems like the correct answer. But that is not the case. Please see photos ① and ②.
Photo ① is a photomicrograph of a 640-mesh plate printed with a pattern with a line width of 15 μm. If you look at where the thread crosses, it completely blocks the pattern. No matter how you look at it, the paste cannot pass through. Therefore, I feel that the answer that "patterns thinner than the thread diameter cannot be printed" is also convincing.
But look at photo ②. The pattern is printed straight. This is a photograph when printing on a special film using the plate of photo ①. How do you feel? Even the crossed threads are well printed.
How could this happen? This is related to the emulsion applied to the plate. The plate is coated with a resin called emulsion on the mesh. This creates a gap between the substrate and the mesh. By allowing the paste to flow through this gap, the pattern can be printed even in the areas where the threads cross.
Therefore, the answer to the question of how thin a line can be printed by screen printing is that "as long as the plate can be made, fine lines can be printed without being affected by the thread diameter."
Rather than thinking about theory, let's try it with screen printing first.
