Screen printing method for making printed circuit boards

I. Drawing (drawing copy)

1. Draw with a computer: Use the circuit design software (protel) to design the required circuit diagram and print it on a special paper film with a laser printer.

2. Hand-drawing: First draw a good draft, then put special tracing sulfuric acid paper (semi-transparent, available in professional shop) on the laser typing film or printing plate. When the outline of the circuit diagram is through the translucent paper or The film is displayed in front of the eyes, and then carefully described by the outline line with a small hook-shaped brush and a plate-making special iron oxide (which can be prepared by oneself) or “Yidege” ink. Requires a well-characterized schematic ink to be dense, uniform, and capable of blocking light.

Second, stretching method

Stretching the net seems simple, but it is not easy. Stretching has a direct impact on the printing. First, soak the selected screen in clean water for 1 to 3 minutes (this procedure is very important), and then soak the screen with a special nail or push pin on the side of the frame to tighten the first, and then further carefully adjust the four sides of the The degree of tightness, so that the screen stretched in the box on the four sides of uniform tension, and finally with a special sticky net glue or "fish beads brand" adhesive glue tightly, to prevent the use of ink leakage.

Third, printing method

1. Use professional exposure box exposure, as shown in Figure 1.

2. Use solar printing, as shown in Figure 2. First, in the dark room, the delineated artwork is placed on the screen, and a transparent glass is placed on the artwork. The glass is covered with a black cloth, and a sponge or foam pad with appropriate thickness is placed on the other side of the mesh frame. Keep the screen and artwork close together, then move to outdoor sunlight, expose the black cloth, and expose it. The length of the exposure time can be determined first according to the strength of the light and then determined. After the exposure is completed, move to the room and rinse with water. After washing, dry it and use it.

Fourth, the printing method

1. Oil-soluble corrosion-resistant inks should be selected for printed circuit boards, and ordinary paints should not be used because paints can cause screen blockage and dryout.

2. Scraper is the main tool in silk screen printing, and it is also a special tool, which is available in professional shops. It is preferable to choose a suitable rubber scraper for the printed circuit board. If you use the triangle in the original text, I believe that the number of printed more, it may make the photosensitive adhesive off.

Source: Instinct Electronics Technology Exchange Network