Detailed explanation of PCB board copying process (PCB board copying)

The technical implementation process of circuit board copying is simple. First, the circuit board to be copied is scanned, and the detailed component positions are recorded. Then, the components are disassembled to make a bill of materials (BOM) and material procurement is arranged. The empty board is scanned into a picture and processed by the copying software to restore it to a PCB board diagram file. Then, the PCB file is sent to the plate making factory for board making. After the board is made, the purchased components are soldered onto the finished PCB board, and then tested and debugged on the circuit board.

1、 Specific steps for copying circuit boards

1. Get a PCB and first record the model, parameters, and position of all components on paper, especially the direction of diodes, diodes, and IC notches. It is best to take two photos of the location of the elemental components with a digital camera. Nowadays, PCB circuit boards are becoming more and more advanced, and some diodes and transistors on them cannot be seen without paying attention.

2. Remove all multi-layer board components and remove the tin from the PAD holes. Clean the PCB with alcohol and place it in the scanner. When scanning, slightly increase the scanning pixels to obtain clearer images. Gently polish the top and bottom layers with water gauze until the copper film is shiny, then place them in the scanner, start PHOTOSHOP, and scan the two layers separately in color. Note that the PCB must be placed horizontally and vertically inside the scanner, otherwise the scanned image cannot be used.

3. Adjust the contrast and brightness of the canvas to create a strong contrast between the parts with and without copper film. Then convert the secondary image to black and white and check if the lines are clear. If not, repeat this step. If clear, save the image as a black and white BMP format file TOP BMP and BOT BMP, if you find any problems with the graphics, you can use PHOTOSHOP to repair and correct them.

4. Convert two BMP files into PROTEL files, and call in two layers in PROTEL. If the positions of PAD and VIA passing through two layers basically coincide, it indicates that the previous steps are well done. If there is any deviation, repeat the third step. So PCB copying is a very patient job, because even a small problem can affect the quality and matching degree after copying.

5. Convert the BMP of the TOP layer to TOP PCB, be sure to convert to the SILK layer, which is the yellow layer, and then trace the lines on the TOP layer, and place the devices according to the second step of the drawing. After drawing, delete the SILK layer. Continuously repeating until all layers are drawn properly.

6. Set TOP in PROTEL PCB and BOT Once the PCB is loaded and combined into one image, it's OK.

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7. Use a laser printer to print the TOP LAYER and BOTTOM LAYER onto transparent film (1:1 ratio), place the film on that PCB, and compare if there are any errors. If they are correct, you have achieved great success.

A copied board identical to the original board was born, but this is only half completed. Further testing is required to ensure that the electronic technology performance of the copied board is the same as that of the original board. If it's the same, then it's really done.

Note: If it is a multi-layer board, it is necessary to carefully polish the inner layer and repeat the third to fifth steps of copying the board. Of course, the naming of the graphics is also different and should be determined according to the number of layers. Generally, double-sided board copying is much simpler than multi-layer board copying, and multi-layer board copying is prone to misalignment. Therefore, multi-layer board copying should be particularly careful and cautious (the internal conductive and non-conductive holes are prone to problems).

2、 Double sided board copying method

1. Scan the upper and lower surfaces of the circuit board and save two BMP images.

2. Open the copying software Quickpcb2005, click on "File" and "Open Base Image", and open a scanned image. Use PAGEUP to zoom in on the screen, see the solder pads, press PP to place a solder pad, press PT to trace the lines... Just like a child's drawing, draw it once in this software, click "Save" to generate a B2P file.

3. Click on "File" and then "Open Base Image" to open another layer of scanned color images;

4. Click on "File" and then "Open" to open the B2P file saved earlier. We see the newly copied board stacked on top of this picture - the same PCB board with holes in the same position, but with different circuit connections. So we click on "Options" - "Layer Settings" to turn off the display of top-level circuits and silk screen, leaving only multi-layer vias.

5. The vias on the top layer are located at the same position as those on the bottom layer image. Now, just like in childhood, we can trace the wiring on the bottom layer. Click 'Save' again - at this point, the B2P file will have both the top and bottom layers of data.

6. Click on "File" and "Export as PCB File" to obtain a PCB file with two layers of information, which can be used to modify the board, create a schematic, or directly sent to a PCB plate making factory for production

3、 Multi layer board copying method

In fact, four layer board copying is repeating two double-sided boards, six layer board copying is repeating three double-sided boards... The reason why multiple layers are intimidating is that we cannot see the wiring inside them. How can we see the inner workings of a precision multi-layer board—— layered.

There are many methods of layering now, such as chemical corrosion and tool peeling, but it is easy to over divide the layers and lose data. Experience tells us that sandpaper polishing is the most accurate.

After copying the top and bottom layers of the PCB, we usually use sandpaper to polish off the surface and display the inner layer; Sandpaper is a common sandpaper sold in hardware stores. It is usually used to lay the PCB flat, then hold down the sandpaper and evenly rub it on the PCB (if the board is very small, you can also lay down the sandpaper flat and use one finger to hold down the PCB and rub it on the sandpaper). The key is to smooth it out so that it can be ground evenly.

Silk screen printing and green oil usually fall off as soon as they are wiped, while copper wire and copper foil need to be wiped carefully a few times. Generally speaking, the Bluetooth board can be wiped clean in a few minutes, while the memory module takes about ten minutes; Of course, with greater strength, it will take less time; Little Flower of Strength will have more time.

Grinding is currently the most common and economical method for layering. We can find an abandoned PCB to try. Actually, grinding the board is not technically difficult, it's just a bit boring and requires some effort. There's no need to worry about the board being worn through to your fingers.

During the PCB layout process, after the system layout is completed, the PCB diagram should be reviewed to see if the system layout is reasonable and can achieve the optimal effect. Usually, the following aspects can be examined:

1. Does the system layout ensure reasonable or optimal wiring, reliable wiring, and reliable circuit operation. When laying out, it is necessary to have a comprehensive understanding and planning of the signal direction, as well as the power and ground network.

2. Whether the size of the printed circuit board matches the dimensions on the processing drawing, whether it meets the requirements of the PCB manufacturing process, and whether there are any behavioral markings. This point needs special attention. Many PCB boards have beautiful and reasonable circuit layouts and wiring designs, but neglect the precise positioning of positioning connectors, resulting in the designed circuit being unable to interface with other circuits.

3. Whether there are conflicts between components in two-dimensional and three-dimensional space. Pay attention to the actual size of the device, especially its height. When welding non layout components, the height should generally not exceed 3mm.

4. Whether the component layout is dense, orderly, and neatly arranged, and whether all components have been laid out. When laying out electronic components, not only should the direction and type of signals be considered, as well as the areas that need attention or protection, but also the overall density of the device layout should be taken into account to achieve uniform density.

5. Can the components that need to be replaced frequently be easily replaced, and is it convenient to insert the plug-in board into the device. It should be ensured that the replacement and plugging of frequently replaced components are convenient and reliable.