- Cut the copper-clad board to the size required for the circuit diagram.
- Put the wax paper on the steel plate, use a pen to engrav the circuit diagram on the wax paper 1: 1, and cut the circuit diagram engraved on the wax paper according to the size of the circuit board, and place the cut wax paper on the printed copper plate. Take a small amount of paint and talcum powder to make a thick and suitable printing material, dip the printing material with a brush, apply it evenly on wax paper, repeat it several times, and the circuit can be printed on the printed board. This stereotype can be used repeatedly and is suitable for small batch production.
- Prepare a corrosive solution with 1 g of potassium chlorate and 40 ml of hydrochloric acid with a concentration of 15%, and wipe it on the circuit board to be corroded.
- Wash the corroded printed board repeatedly with water. Wipe off the paint with banana water and clean it a few times to make the printed board clean without leaving any corrosive liquid. Apply a layer of rosin solution and dry the holes.
- Method Two
- Printing plate illustration. The pads in the figure are indicated by dots, and a single line can be connected, but the location and size must be accurate.
- Cut the printing plate according to the size of the printing plate, and clean the copper foil.
- Use carbon paper to copy the diagram to the printing board. If the circuit is simple and the producer has some experience in making boards, this step can be omitted.
- According to the actual situation of the component, paste the standard pre-cut symbols (pads) with different inner and outer diameters; then, depending on the current, paste tape lines of different widths. Standard pre-cut symbols and tape are available in electronics stores. Common specifications of pre-cut symbols are D373 (0D-2.79, ID-0.79), D266 (0D-2.00, ID-0.80), D237 (OD-3.50, ID-1.50), etc. It is best to buy paper-based materials (Black), plastic-based (red) materials are not used as much as possible. Common specifications of tape are 0.3, 0.9, 1.8, 2.3, 3.7 and so on. The units are millimeters.
- Tap the sticker with a softer hammer, such as smooth rubber, plastic, etc., to make it fully adhere to the copper foil. Focus on the turn and overlap of the line. In cold weather, it is best to warm the surface with a heater to enhance the adhesion effect.
- Put in ferric chloride for corrosion, but please note that the liquid temperature is not higher than 40 degrees. After the corrosion, it should be taken out and rinsed in time, especially in the case of thin threads.
- Make holes, brighten the copper foil with fine sandpaper, apply rosin alcohol solution, and dry it. The quality of this printed board is very close to that of a regular printed board. 0.3mm tape can pass between the IC’s two feet, which can greatly reduce the short jumper on the front of the board to save time and time.
Dissolve one piece of paint (ie shellac, available from chemical raw materials stores) in three parts of anhydrous alcohol and stir appropriately. After it is all dissolved, add a few drops of medical purple potion (gentian violet) to make it It shows a certain color and can be used as a protective paint to paint circuit boards after being stirred evenly.
First polish the copper-clad board with fine sandpaper, and then use the duckbill pen (or ink duckbill on the compass to draw graphics on the drawing instrument) to draw. The duckbill pen has a nut to adjust the stroke thickness and the stroke thickness. Adjustable, and can draw straight lines and triangles to draw very thin straight lines, and the drawn lines are smooth and uniform, without edge jagged, giving a smooth and fluent feeling; at the same time, it can also be in the free place of the circuit board Write Chinese characters, English, pinyin or symbols.
If the line drawn is soaked to the surroundings, the concentration is too small, and you can add a little varnish; if you cannot drag the pen, it is too thick, and you need to drip a few drops of absolute alcohol. It doesn’t matter if it is wrong, just use a small stick (match stick), make a small cotton swab, dipped in a little alcohol, you can easily wipe it off, and then redraw it. Once the circuit board is drawn, it can be etched in a ferric chloride solution. After the circuit board is corroded, it is also very convenient to remove the paint. You can wipe off the protective paint with a cotton ball dipped in absolute alcohol, and you can apply pine perfume after drying it.
Because the alcohol evaporates quickly, the prepared protective paint should be placed in a vial (such as an ink bottle) and sealed. Do not forget to close the cap after use. If the concentration becomes thicker when you use it next time, just add an appropriate amount. An absolute alcohol is sufficient.
Stick the instant paste on the copper foil of the copper-clad board, then draw the circuit on the surface, and then cut through the surface layer with a cutter to form the required circuit. Remove the non-circuit parts and finally use ferric chloride to etch or current The electrolytic method can produce a more ideal circuit board.
The corrosion temperature can be performed at about 55 ° C, and the corrosion rate is faster. Rinse the corroded circuit board with water, remove the sticky notes on the circuit, make holes, wipe and apply rosin alcohol solution for use.
- Method five
- Reasonably arrange the density of the components and the position of each component according to the shape of the components used in the circuit schematic and the size of the printed board area. The location of components should be determined according to the principle of first large, then small, first whole, then local, so that adjacent components in the circuit are placed nearby and arranged neatly and evenly.
- The connecting wires between the components should not be turned at right angles at the bends and the intersection of the two wires. They must use curve transitions, and they should not cross and detour too far. When some wires can’t do this, you can consider printing the wires on the reverse side of the printed board, and then use piercing nails to connect to the front circuit, or use insulated wires to connect the components.
- The distance between the input part and the output part is better, so as not to interfere with each other.
- Method six
The “sub-printing” method for making printed circuit boards is as follows:
- Print the circuit board diagram on 80g copy paper on a printer at a 1: 1 ratio. It is also possible to draw by hand, but the paper should be flat.
- Find a fax machine, remove the fax paper from the machine, and replace it with hot melt plastic film. Put the circuit diagram into the entrance of the facsimile machine, and use the copy key of the facsimile machine to copy the circuit diagram on the thermoplastic film. At this time, the “print manuscript” of the printed circuit board is ready.
- Use double-sided tape to affix the plastic film to the copper plate. Pay attention to be flat, do not wrinkle, and the tape cannot cover the melting part, otherwise it will affect the production effect of the circuit board.
- Brush the paint evenly on the plastic film with a paint brush. Note: you cannot brush back and forth, you can only brush in one direction, otherwise the plastic film will wrinkle together, and the lines on the copper plate will overlap. After the circuit diagram has been brushed all over, carefully remove the plastic film. At this point, a printed circuit board is printed. After drying, it is ready for corrosion.
If you want to print multiple pieces, you can make a wooden frame larger than the circuit board, and apply the silk screen to the wooden frame to fix it. Then use double-sided tape to paste the plastic film fixed under the screen. Place the copper-clad board on the table, close the screen rack (the printed picture and the copper-clad board should be aligned left and right), use a paint brush to brush the paint in one direction and remove the wire rack. The printed circuit board is printed. If there are defects, they can be modified with paint and bamboo.