This method is the most direct. The designed copper foil pattern is copied to the copper foil surface of the copper clad plate with carbon paper, and the special engraving tool made by hacksaw blade is used to directly carve along the edge of the copper foil pattern on the copper clad plate, cut to the depth as far as possible, and then tear off the unnecessary copper foil outside the figure, and then drill the hole with the electric hand drill. The key of this method is: the strength of the portrayal should be enough; Remove excess copper foil from the edge of the plate, when the operation is good, you can gradually remove pieces, you can use small needle-nose pliers to complete this step. Some experimental versions of small circuits are suitable for this method.
Manual painting method
It is to draw the printed figure directly on the copper clad plate with a pen, and then carry out chemical corrosion and other steps. This method seems simple, the actual operation is not easy! Now the electronic components are small, the pin spacing is smaller (millimeter), the copper foil line is also small, and the line drawn on is difficult to modify, to draw such a board depends entirely on your pen time. Lesson learned: Both the "paint" and the choice of brush are critical. I used to paint the circuit board with red nail polish in a medical syringe, the effect is good, but the tip of the needle should be properly processed; Some people also introduce the use of paint chips dissolved in anhydrous alcohol, using a pen to sketch, the specific method is as follows:
One piece of paint (that is, shellac, available in chemical raw material stores), dissolved in three parts of anhydrous alcohol, and properly stirred, to be all dissolved, drop a few drops of medical violet (gentian violet), so that it presents a certain color, stir evenly, can be used as a protective paint to depict the circuit board.
First polish the copper sheet with fine sandpaper, and then use the pen in the drawing instrument (or the ink pen used to draw graphics on the compass) to describe, the pen has a nut to adjust the stroke thickness, the stroke thickness can be adjusted, and can use the ruler, triangle ruler to describe a very thin straight line, and the line is smooth, uniform, no edge serrated, giving people a smooth, fluent feeling; At the same time, you can also write Chinese characters, English, pinyin or symbols in the idle place of the circuit board to draw the line, if the surrounding infiltration, the concentration is too small, you can add a little paint; If you do not start, it is too thick, need to drop a few drops of anhydrous alcohol. It doesn't matter if you make a mistake, just use a small stick (matchstick), make a small cotton swab, dip it in a little anhydrous alcohol, and then easily erase it and redraw it. Once the board diagram is drawn, it can be corroded in ferric chloride solution. After the corrosion of the circuit board, it is also very convenient to paint, with a cotton ball dipped in anhydrous alcohol, you can wipe off the protective paint, a little dry, you can then apply rosin water to use.
Because the alcohol volatilizes quickly, the prepared protective paint should be placed in a small bottle (such as ink bottle) sealed storage, do not forget to cover the bottle after use, if the next use, found that the concentration has become thicker, as long as the appropriate amount of anhydrous alcohol can be added.
① Precut symbol method
Electronics stores sell a "standard pre-cut symbol and tape." 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 base (red) materials as far as possible. Tape commonly used specifications are 0.3, 0.9, 1.8, 2.3, 3.7 and so on. The units are millimeters. According to the circuit design layout, the corresponding symbol and tape can be selected and pasted to the copper foil surface of the copper-covered plate. Use a soft hammer, such as smooth rubber, plastic, etc., to beat the sticker so that it is fully adhered to the copper foil. Focus on tapping the bend and lap of the line. When the weather is cold, it is best to warm the surface with a heater to strengthen the adhesion effect. Once posted, it's ready for corrosion.
② Self-adhesive paper mapping method (recommended)
Use design software such as Protel or PADS to draw the printed board diagram, output it to the self-adhesive paper with a needle printer, paste the self-adhesive paper on the cleaned coated copper plate, cut out the outline along the strip with a paper cutting blade, and tear off the part of the paper that needs to be corroded. Put into the less iron trichloride solution corrosion, cleaning, drying can be put into use. This method is similar to the engraving method, but it saves a lot of effort than the engraving method, and can ensure the beauty and accuracy of the printed wire!
③ Experience everyone knows that ferric chloride solution corrosion is very slow, the author used dilute nitric acid instead, do this experiment, the corrosion speed is amazing, five minutes or so can be done, the quality is no difference with trichlorine, suggest diy try! But this method is more dangerous, remind producers to pay attention to, do not let any part of the body touch the corrosive fluid, otherwise the consequences are unimaginable! Remember! Remember!
④ Mimeograph method:
Put the wax paper on the steel plate, use a pen to carve the circuit diagram 1:1 on the wax paper, and cut the circuit diagram engraved on the wax paper according to the size of the circuit board, and put the cut wax paper on the printed copper plate. Take a small amount of paint and talc powder into a thin thick suitable printing material, dip the brush into the printing material, evenly coated on the wax paper, repeated several times, the printed board can print the circuit. This rigidity can be used repeatedly and is suitable for small batch production. Tip: Using the photoelectric copying machine, you can automatically burn wax paper of 1:1 size according to the design drawing.