Here are the seven methods for introducing PCB CCL in detail.
The designed copper foil pattern is duplicated on the copper-clad copper foil surface, and the special engraving cutter ground using the steel saw blade is directly drawn on the copper-clad board along the edge of the copper foil pattern, and cut into the depth as much as possible. Then remove the copper foil that is not needed outside the pattern, and then drill the hole with your hand drill. The intensity of the painting should be sufficient; the excess copper foil should be removed from the edge of the board. When the operation is good, it can be gradually removed in pieces. You can use small needle-nosed pliers to complete this step. Some small circuit experimental versions are suitable for this method.
Use the pen to directly draw the printed image on the copper clad plate, and then carry out the steps of chemical etching. This method seems to be simple, and the actual operation is not easy! Today's electronic components are small, the pitch of the pins is smaller (on the order of millimeters), the copper foil traces are also small, and the lines drawn are still difficult to modify.
To draw such a board, you should look at your writing. . The experience is that the choice of “pigments” and brushes is critical. I used to use red nail polish in a medical syringe, depicting the circuit board, the effect is good, but the tip of the needle should be properly processed; some people also use the paint strip to dissolve in anhydrous alcohol, using the duck-bill pen to draw, the specific method is as follows : Dissolve a piece of lacquer (that is, shellac, which is available at chemical raw materials stores), dissolve it in three parts of absolute alcohol, and mix it properly.
After all of it is dissolved, add a few drops of medical purple syrup (gentian violet) to make It presents a certain color, and after mixing evenly, it can be used as a protective paint to depict the circuit board. First use a fine sandpaper to polish the copper plate, and then use the duckbill pen in the drawing instrument (or the ink duckbill pen used to draw graphics on the compass) to draw.
The duckbill pen has a nut that adjusts the thickness of the stroke, and the thickness of the stroke. Adjustable, and can use a ruler, triangle ruler to draw a very thin line, and the lines drawn are smooth, uniform, no edge serrated, giving a smooth, fluent feeling; at the same time, can also be in the free space of the board Write lines drawn in Chinese characters, English, pinyin or symbols. If you are soaked in the surroundings, the concentration is too small, you can add a little paint; if you can't open the pen, it is too thick, you need to drop a few drops of absolute alcohol.
In case it is wrong, it doesn't matter. Just use a small stick (matchstick), make a small cotton swab, and lick a little bit of alcohol, then you can easily wipe it off and then re-render it. Once the board drawing is completed, it can be corroded in the ferric chloride solution. After the circuit board is corroded, it is very convenient to paint. Use a cotton ball to rub the anhydrous alcohol, then you can wipe off the protective paint.
After drying it, you can apply it with pine perfume. Since the alcohol evaporates quickly, the prepared protective paint should be sealed in a small bottle (such as an ink bottle). Don't forget to cover the bottle after use. If it is used next time, the concentration will become thicker, just add the right amount. Anhydrous alcohol can be used.
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. It is best to buy paper-based materials. (Black), plastic (red) materials are not used as much as possible. Common specifications for tapes are 0.3, 0.9, 1.8, 2.3, 3.7, etc. The units are all in millimeters. According to the circuit design layout, select the corresponding symbol and tape, and paste it onto the copper foil surface of the copper plate. Use a soft hammer, such as smooth rubber, plastic, etc. to hit the map to make it fully adhere to the copper foil. Focus on the corners of the lines and the joints. When it is cold, it is best to warm the surface with a heater to enhance the adhesion.
After the post is posted, the etching process can be carried out. Self-adhesive paper mapping method uses Protel or PADS design software to draw the printed board diagram, use the pin printer to output to the self-adhesive paper, paste the self-adhesive paper on the copper plate that has been cleaned, and cut the paper. The blade is cut along the outline of the line, tearing off some of the strip to be corroded. It is put into corrosion after being put into the trichlorinated iron solution, washed, dried and put into use.
This method is similar to the engraving method, but it saves a lot of effort than the engraving method, and can guarantee the beauty and precision of the printed wires! Experience everyone knows that the corrosion of ferric chloride solution is very slow. I used this dilute nitric acid instead of this experiment. The corrosion rate is amazing, and it can be done in about five minutes.
The quality is no different from trichloro. It is recommended that diy Try it! However, this method is more dangerous, remind the producer to pay attention, do not let any part of the body touch the corrosive liquid, otherwise the consequences are unimaginable! Remember! Remember!
1: 1 cutting split paper power train on purpose paper on an embossed steel sheet, special purpose cutting off split imprint Paper top up electric circuit. Excavitable Paper Paper Exposed on Printable Bronze Plate. Small amount of oil Urushi talcum powder, structured thickener suitable printing material, brush brushed printing material, uniform coating application on paper, multiple copies, printed wiring board power lines. seed engraving board impression possible for doubling, fitting small amount of production. Presentation: Used light illuminated cantilever, yourself permanent installation plan paper, self - sculpture engraving 1: 1 scale measure.
Hot melt film making
This method is collected from online articles and the feasibility is not verified for reference.
1. Print the board diagram on a printer at a ratio of 1:1 on 80 grams of copy paper. It can be drawn by hand, but the bottom paper should be flat.
2. Find a fax machine, take out the fax paper in the machine, and replace it with a hot melt film. Place the circuit diagram at the entrance of the fax machine and copy the circuit diagram on the hot melt film using the copy button of the fax machine. At this point, the "printed manuscript" of the printed circuit board is ready.
3. Use a double-sided tape to flatten the plastic film on the copper plate. Pay attention to the flatness, not wrinkle, the tape paper can not cover the melted part, otherwise it will affect the production effect of the circuit board.
4. Use a paint brush to evenly brush the paint on the plastic film. Note: You can't reciprocally brush, you can only brush in one direction, otherwise the plastic film will wrinkle and the lines on the copper plate will overlap. After the circuit diagram is completely brushed, carefully remove the plastic film. At this point a printed circuit board is printed. After drying, it can be corroded. If you want to print more than one piece, you can make a wooden frame that is a little bigger than the board.
Apply the screen to the wooden frame and fix it. Then use a double-sided tape to attach the film to the bottom of the screen. Place the copper-clad plate on the table, close the wire mesh frame (the printed image and the copper-clad plate should be aligned to the left and right), use the paint brush to brush the paint in one direction, and remove the net frame.
The printed circuit board is printed. If it is defective, it can be modified with paint and bamboo. The above process must be noted that when painting, the hand should be light and heavy, too heavy paint film is too thick, the lines will run lace, too light lines will break. The plastic film must face up.
Use pre-coated photosensitive copper plate
A special copper-clad laminate is used, and the surface of the copper-plated layer is pre-coated with a layer of photosensitive material, so it is called “pre-coated photosensitive copper plate”, also called “photosensitive plate”. The method of making is as follows: Print the circuit diagram 1:1 on a relatively transparent (thin), at least one side of the paper that is smooth and flat, and print the image on the flat side. Then put the smooth surface of the paper against the photosensitive circuit board (clamped with glass) and put it in the sun for 2-8 minutes.
The length of time is related to the strength of the sun. It can be irradiated for about 20 minutes on a cloudy day. Note: The above is the reference time of the transparencies. The time of the white paper is extended according to the transparency of the paper. This process must not move the relative position of the paper and the board, and be close to it. The board is then placed under developer to develop (washing off unwanted sensitizers), leaving the developer to prevent copper from reacting with the next ferric chloride. This process typically takes 1-3 minutes.
Time is inversely proportional to the degree of exposure. If the exposure is excessive, the development time will be short. If the exposure is insufficient, the development time will be long, even longer than 10 minutes. In addition, it is related to the concentration of developing water. However, it is strongly recommended that exposure should not be excessive, preferring to develop for a longer period of time, so that no mistakes can be made and 100% success can be guaranteed. Finally, after corrosion by ferric chloride, it usually takes about 10-60 minutes.
Since the above process is that light directly determines the retention of copper, the accuracy can be very high. Therefore, the skilled person can generally make a high-precision circuit board within 30 minutes, and the thermal transfer paper can also be used for exposure after printing without heating the transfer process. The effect is better, the price should be much more expensive, but generally it is acceptable. Single-panel production: PCB drawing of the computer, printing 1:1 black and white 720dpi drawings (component surface) with inkjet paper, if you use a laser printer to output drawings.
Take a piece of photosensitive plate of the same size as the drawing and remove the protective film. Use a glass plate or a plastic transparent plate to press the drawing against the photosensitive PCB and expose it to sunlight for 5-10 minutes. Development is carried out with the accompanying developer 1:20 water, and when the exposed portion (unwanted copper coating) is completely exposed, it is rinsed with water and then corroded with ferric chloride.
After the operation is proficient, it can produce a trace with an accuracy of 0.1mm! The production of double-sided circuit boards: the steps refer to the single-panel, and the double-panel is mainly accurate on both sides. It can be exposed on both sides, but the time should be the same. On the other side, the other side should be protected with black paper.
Thermal transfer method
1. A printout device for producing a high-precision plastic toner solder mask, such as a laser printer or a copier (copying of the original is required for the copying machine, and the original can be printed with an inkjet printer).
2. An electric iron that can be used.
3. A smooth backing paper with a sticker.
4. A certain amount of ferric chloride corrosive solution, depending on the size of the plate. In addition, it is better to have a digital thermometer with a range of 0 to 200 degrees, and a high-end digital multimeter is also included. Software: Low version of PROTEL, such as PROTEL2.5 Chinese version of the high version of PROTEL, such as PROTEL99SE Chinese version or even just a WIN drawing program is to have a software that can draw.