PCB Technical - Various PCB fabrication methods and processes

Introduction of PCB Production Method

PCB Production Method 1:

(1) Cut the copper clad plate into the required dimensions for the circuit diagram.

(2) Place the wax paper on the steel plate, use a pen to engrave the circuit diagram on the wax paper 1:1, cut the circuit diagram on the wax paper according to the dimensions of the circuit board, and place the cut wax paper on the printed copper plate. Take a small amount of paint and talc powder to make a suitable thick print, dip the print with a brush, and evenly spread it on wax paper. Repeatedly, the printed circuit can be printed on the printed board. This stereotype can be used repeatedly and is suitable for small batches.

(3) Corrosive solution made of 1 g potassium chlorate and 40 ml hydrochloric acid with 15% concentration is applied to corrode the circuit board where it needs to be corroded.

(4) Wash the corroded printed circuit board repeatedly with water. Wipe the paint off with banana water and clean it several times to make the printed board clean without leaving any corrosive liquid. Drill holes after applying a layer of rosin solution to dry.

PCB Production Method 2:

(1) making printed circuit boards. The bonding pads in the drawing are indicated by dots, and the connection can be made in a single line, but in a single position. The dimensions need to be accurate.

(2) Tailor the printed plates according to the size of the printed plates and clean the copper foil.

(3) Copy the drawing onto the printed board with duplicate paper. This step may be omitted if the line is simple and the manufacturer has some experience in making the board.

(4) Paste standard pre-cut symbols (pads) with different inside and outside diameters according to the specific conditions of the components; Then paste tape lines of different widths by the size of the apparent current. For standard pre-cut symbols and tapes, electronics stores are available. Common specifications for 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. Purchase paper-based materials (black), plastic-based (red) materials as far as possible. Common specifications of tape are 0.3.0.9.1.8.2.3.3.7, etc. The units are in millimeters.

(5) Use a softer hammer, such as smooth rubber. Knock patches, such as plastics, to make them fully adhere to the copper foil. Focus on the line turn. Joint. When it is cold, heat the surface with a heater to enhance the adhesion.

(6) Corrosion in ferric trichloride, but note that the liquid temperature is not higher than 40 degrees. After the corrosion is finished, remove and rinse it in time, especially in the case of thin lines.

(7) Make a hole, polish the copper foil with fine sandpaper, apply the rosin alcohol solution, and then dry it. The quality of this type of board is very close to that of a regular board. 0.3mm tape traverses between IC feet, greatly reducing short jumpers on the front of the board to save time. Save time.

PCB Production Method 3:

Dissolve one piece of lacquer (i.e. shellac, available in chemical material stores) in three portions of anhydrous alcohol and stir it properly. After all dissolve, drop a few drops of medical purple water (Gentian violet) to give it a certain color. After stirring evenly, it can be used as a protective paint to depict the circuit board.

First polish the copper clad plate with fine sandpaper, then use the duckbill pen in the drawing instrument (or the ink duckbill pen on the compass used to draw graphics) to describe it. The duckbill pen has a nut to adjust the stroke thickness, and the stroke thickness can be adjusted, and a straight ruler can be borrowed. A triangle ruler draws very thin straight lines and smooth lines. Even, no edge jagged, giving people smooth. Fluent sensation; At the same time, you can also write Chinese characters in the free place of the circuit board. English. Phonetic or Symbol

The lines that are drawn, if they infiltrate the surroundings, are too low in concentration and can be slightly lacquered. If you can't drag the pen, it's too thick and needs to be dripped with a few drops of absolute alcohol. In case it is wrong, just make a small cotton swab with a stick (matchstick) and dip it in a little absolute alcohol, then wipe it off conveniently and redraw it. Once the printed circuit board is drawn, it can be corroded in ferric trichloride solution. After the printed circuit board is corroded, it is easy to remove the paint. If you dip the cotton ball in absolute alcohol, you can erase the protective paint and dry it slightly, then you can use it with rosin.

As alcohol evaporates quickly, the prepared protective paint should be sealed and stored in a small bottle (e.g. an ink bottle). Do not forget to cover the cap after use. If you find that the concentration becomes thicker the next time you use it, simply add some absolute alcohol.

PCB Production Method 4:

An ideal circuit board can be made by immediately pasting the copper foil onto the copper clad board, drawing the circuit on the surface, carving the surface layer with a cutter to form the required circuit, removing the non-circuit part and using ferric chloride corrosion or current electrolysis.

The corrosion temperature can be carried out at about 55 C, and the corrosion speed is faster. Corroded circuit boards are rinsed clean with clean water, instant stickers are removed from the circuit, holes are made, and rosin alcohol solution is wiped clean for use.

PCB Production Method 5:

(1) Depending on the shape of the components used in the circuit schematic diagram and the size of the printed board area, the density of the elements and the position of the elements should be reasonably arranged, and the riveting nut post used as fastener should also be reasonably arranged. The position of components should be determined according to the principle of "first big, then filial, first whole, then local", so that the adjacent components in the circuit are placed close to each other and arranged neatly and evenly.

(2) The connecting wires between the components must not be at right angles at corners or at intersections between the two lines. They must be transitioned by curves or be too far apart from each other. When some wires can't do this, consider printing the guide on the back of the printed board, connecting the front circuit with a pin, or using an insulated wire to connect the welded elements.

(3) The input part and the output part should be a little farther away from each other to avoid interference.

PCB Production Method 6:

Radio enthusiasts have had trouble making printed circuit boards. Now we introduce a sub-printing method for making printed circuit boards. The methods are as follows:

(1) Print the printed circuit board drawings on 80g copier paper at a scale of 1:1 on the printer. Manual drawing is also possible, but the base paper should be flat.

(2) Find a fax machine, take out the fax paper from the machine and replace it with a hot-melt plastic film. Put the circuit diagram in the entrance of the fax machine and use the copy key of the fax machine to copy the circuit diagram on the thermoplastic film. Now the "printed original" of the printed circuit board is ready.

(3) Use double-sided tape paper to place the drawn plastic film flat on the copper clad board. Note to be flat, not wrinkle, tape paper can not cover the melting part, otherwise the effect of the circuit board will be affected.

(4) Brush the paint evenly on the plastic film with a paint brush. Note: You cannot brush back and forth, but in one direction in turn. Otherwise, the plastic film wrinkles together and the lines on the copper plate overlap. When the circuit diagram is brushed through carefully remove the plastic film. A printed circuit board is ready. After drying, it will corrode.

If you want to print several pieces, you can make a wooden frame a little larger than the printed circuit board, and lay the wire mesh flat on the wooden frame to fix it. Then use double-sided tape paper to attach the shaded plastic film under the wire mesh. Place the copper clad sheets on the table, close the wire mesh rack (the print should be aligned left and right with the copper clad sheets), brush the paint one by one with the paint brush, and remove the wire mesh rack. The printed circuit board is ready. If defective, can be modified with paint and bamboo slices.

In the above process, it should be noted that when painting, the hand should be exerted properly, too heavy paint film is too thick, lines will run lace, too light lines will break lines. The plastic film must face up.

The method for printing part drawings is the same as described above.