Five methods and steps commonly used to make circuit boards
Published time: 2019-08-12
Circuit boards are widely used in life, many people will not make circuit boards, and some people make a single method, then you will introduce a variety of methods to make electric boards, and read the full text together!
Photosensitive plate method
It is simpler to make, especially when it has a large area of grounding lines. High precision, but exposure requires experience when making thin lines.
1.Draw PCB circuit diagrams with software.
2. Take a film paper and print the PCB pattern on the film paper through a laser printer. After the printing is completed, the excess film portion is cut off with scissors.
3, take the material, according to the size of the PCB is slightly larger, take the material from the large photosensitive plate. The green oil ink can be seen by opening the film on the photosensitive plate. At this time, the printed PCB plate film is immediately placed on the photosensitive plate to prepare for exposure.
4. Exposure, sandwich the photographic plate and the plate-making film with two pieces of glass, keep it flat, and then place it under the fluorescent lamp. The standing time is generally between 15 and 20 minutes. Of course, this is only a reference value. The exposure time is closely related to the light intensity and the distance from the light source. If the ultraviolet light is used, the time is shorter. Therefore, the specific time should be based on your actual situation.
5. Configure the developer, the developer and water are proportioned, and stir constantly with water in the chopsticks. After the developer particles are completely dissolved, place the exposed photosensitive plate in it, and shake the plate continuously. Observe carefully. The green ink is slowly being dispelled, and copper foil is constantly exposed. And the line is also continuously displayed, the development time is generally about 5 minutes.
6. Configure the corrosive solution for corrosion.
The production is relatively complicated and has a great relationship with the operator's proficiency. Especially the exposure control during plate making is very important, but it can perform well for thin lines and large grounding wires. Especially in mass production, it can show its advantages. If you only need to make a few boards, you will find this method very cumbersome, but when you need to make hundreds of thousands of boards, then you should not choose it.
1. Draw a picture, draw a circuit diagram in the computer with protel board drawing software, and print the circuit diagram onto the plate-making film.
2. Ingredients, mix about 50 grams of photosensitive glue with about 4 grams of ammonium dichromate, and stir the two evenly with a stick. Observe the small granular ammonium dichromate in the colloid, which indicates that it has been stirred. success. The amount of the above two can be different depending on the experience of each person. The result of different ratios is that the exposure time is different. That is to say, the ratio affects the exposure time.
3, glue, take a 420 mesh wire rack, it is best to rinse with water to remove the dust deposited on the wire mesh, and then blow dry with a hair dryer. Then use a stainless steel scraper to apply the prepared photoresist to the screen. Note that it needs to be coated on both the front and back sides of the screen. After the basic coating is completed by the eyes, the excess photoresist is scraped off with a stainless steel scraper. If it is a character layer or a solder mask that needs to be printed, a 120 mesh or 100 mesh screen can be used.
4. Exposure, place the printed plate-making film on the wire mesh frame coated with the photosensitive glue, and place a flat glass, and finally place the whole device under the 40W fluorescent lamp, or 60W fluorescent lamp, two The distance is about 15 cm. The exposure time is about 5 minutes (the actual operation time may change, and there are many factors affecting the exposure time). After the exposure, use a certain pressure of water, such as (tap water, water gun) to rinse the screen, if the plate is successful, you will see the circuit lines, text and so on left on the wire mesh frame.
5, pre-press preparation, first fix the fixed frame on a certain surface, and then fix the finished version of the wire mesh frame on the fixed frame. The fixed frame can be an iron frame or an aluminum frame, and the aluminum is cheap. But the stability is not as good as iron. If you want to make a double panel, or if you might want to multi-color overprint in the future, you should choose an iron holder. Take a number of copper plates, a colloidal blade and a bottle of screen printing ink.
6, printing, a variety of colors are available, but if you are using a circuit board, then you can choose one or two. Before printing, it is recommended to take a few pieces of waste paper as test prints, place the substrate (paper, copper clad laminate) under the wire mesh frame, then apply a little screen ink on the wire mesh frame, and use a colloid scraper on the wire mesh frame. Scratch again, when the circuit is printed on the paper. Remove the paper, put another paper to be printed, and scrape it again and again, then the second one will be printed. Repeat this until all paper or copper clad laminates have been printed.
7. Cleaning, in order to reduce costs, the wire mesh frame can be reused, but it must be processed. First use the pine perfume to clean the silk screen ink left on the silk frame. Then, the photoresist which has been solidified on the wire mesh frame is washed away by a stripping agent, and the cleaning liquid is obtained by taking 10 g of the release agent and 500 g of water. After the white release agent is completely dissolved, it is scrubbed with cotton or cloth. This process generally takes 5 minutes to 10 minutes. After washing with eyes, it is basically dissolved and then washed with water.
8. Configure the etching solution and corrode the circuit board.
9. Cleaning, remove the corroded circuit board from the ferric chloride solution, first wash it with water, then clean it with gasoline. Of course, it is also possible to wash the screen printing ink by sanding with sandpaper.
Descriptive method is the one that requires the least amount of tools for making a circuit board, and the simplest production process, but the precision is not very high, suitable for beginners.
1. Draw a PCB diagram on the Protel software.
2. Print with a printer.
3. Prepare the same size CCL.
4. Take a copy paper (similar to the blue paper used for invoicing) and copy the PCB image printed on plain white paper to the copper plate by ballpoint pen drawing.
5. Depicting, taking a very fine oily marker, depicting the lines that have just been copied to the copper plate. For a drawing that is not obvious enough, it can be repeated to ensure that the lines of the depiction are not broken. Also note that care must be taken when drawing the PCB drawing to prevent the lines that are not intersecting from sticking due to carelessness.
6. Configure the etching solution to corrode the circuit board. You can use electrolytic, hydrogen peroxide + concentrated hydrochloric acid + water, ferric chloride solution to corrode the copper clad plate.
7. Drill holes in the circuit board with a drill. We recommend using a micro bench drill for high precision punching.
Thermal transfer method
The production is relatively simple, especially when the thin lines are displayed, the production accuracy is largely determined by the equipment, and has nothing to do with the human operation program. Beginners can also make beautiful circuit boards. But laser printers are needed, and there are often some shortcomings for large grounded lines.
1. Draw a picture and draw a circuit diagram in the computer with protel board drawing software.
2, printing, remove the thermal transfer paper, the effect of white is better than the yellow effect, and if you make a small circuit, you can cut the thermal transfer paper with scissors, and then use a laser printer to print.
3, thermal transfer, turn on the heat transfer machine power switch, and adjust the temperature at 180 degrees, because the heat transfer machine needs to preheat for 5-10 minutes, so you can print out during the heat transfer machine preheating period The PCB diagram is used to unload the copper clad laminate. If the copper plating is spotted, it is OK to polish it with sandpaper. The thermal transfer paper is reversely attached to the copper-clad board and placed in a heat transfer machine, and the thermal transfer machine automatically completes the thermal transfer work. If you do not have thermal transfer, the household iron can also be used. It just requires a little skill and trouble in the operation.
4. Use an oily marker to draw irregular lines or lines that have not been transferred, and then arrange the etching solution for corrosion.
5. Punch holes with a puncher.
Photosensitive dry film method
This method has certain advantages in cost compared with the photosensitive plate method, and has certain advantages in the quality of the circuit produced by the thermal transfer method. But her shortcomings are that the operation is somewhat difficult, not as simple as the thermal transfer method and the photosensitive plate method. The production process is the same as that of the photosensitive plate method, which is different when preparing the plate. One is a made photosensitive plate, and the other is a copper-clad plate plus a photosensitive film.
The above main introduction of the five ways to make the board, if you are interested, you can do it yourself.
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