What is copy board?
The technical implementation process of PCB copy board is simply to scan the circuit board to be copied, record the detailed component location, and then disassemble the bill of materials (BOM) of the component and arrange the material purchase, and the empty board Scan into pictures and process them into pcb board drawing files by copying board software, and then send the PCB files to the plate making factory. After the board is made, the purchased components are welded to the finished PCB board, and then go through the circuit board test And debugging.
The specific steps of PCB copy board
1. Get a PCB, first record the model, parameters, and location of all vital parts on the paper, especially the direction of the diode, the triode, and the direction of the IC gap. It is best to use a digital camera to take two photos of the location of vitality pieces. Nowadays, the PCB circuit board is getting more and more advanced. The diode transistor above can’t be seen at all.
2. Remove all the multi-layer board copy board parts, and remove the tin in the PAD hole. Clean the PCB with alcohol, and then put it into the scanner. When scanning, the scanner needs to adjust the scanned pixels slightly to get a clearer image. Then lightly polish the top and bottom layers with gauze paper until the copper film is shiny, put it into the scanner, start PHOTOSHOP, and scan the two layers separately in color. Note that the PCB must be placed horizontally and vertically in the scanner, otherwise the scanned image cannot be used.
3. Adjust the contrast, lightness and darkness of the canvas to make the part with copper film and the part without copper film strong contrast, then turn the sub-picture to black and white, check whether the line is clear, if not clear, repeat this step. If it is clear, save the picture as black and white BMP format files TOP.BMP and BOT.BMP. If you find a problem with the picture, you can use PHOTOSHOP to repair and correct it.
4. Convert the two BMP format files into PROTEL format files, and transfer two layers in PROTEL. If the positions of PAD and VIA in the two layers basically coincide, it indicates that the previous steps have been done well. If there is a deviation , Then repeat the third step. Therefore, PCB copying is a task that requires patience, because a small problem will affect the quality and the degree of matching after copying.
5. Convert the BMP of the TOP layer to TOP.PCB, pay attention to the SILK layer, which is the yellow layer, then you can trace the line on the TOP layer, and place the device according to the second step drawing. Delete the SILK layer after painting. Keep repeating until you have drawn all the layers.
6. In PROTEL, transfer TOP.PCB and BOT.PCB into one picture and it will be OK.
7. Use a laser printer to print TOP LAYER and BOTTOM LAYER on transparent film (1: 1 ratio), put the film on that PCB, and compare whether it is wrong. If it is correct, you are done.
A copy board that was the same as the original board was born, but it was only half finished. There is also a test to test whether the electronic performance of the copy board is the same as the original board. If it is the same then it is really done.
Remarks: If it is a multi-layer board, you need 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. It is much simpler than multi-layer board. Multi-layer board copy is prone to misalignment, so multi-layer board copy board should be especially careful and careful (the internal vias and non-vias are prone to problems).
Double panel copying method
1. Scan the upper and lower layers of the circuit board and save two BMP pictures.
2. Open the copyboard software Quickpcb2005, click “File” and “Open Basemap” to open a scanned picture. Use PAGEUP to enlarge the screen, see the pad, press PP to place a pad, see the line and press PT to traverse … Just like a child drawing, draw it again in this software, click “Save” to generate a B2P file.
3. Click “File” and “Open Basemap” to open another layer of scanned color images.
4. Click “File” and “Open” to open the previously saved B2P file. We see the board just copied, stacked on top of this picture-the same PCB board, the holes are in the same position, but the wiring connection is different . So we press “Options”-“Layer Settings”, here to close the display of the top line and silk screen, leaving only multiple layers of vias.
5. The vias on the top layer are in the same position as the vias on the bottom picture. Now we can trace the lines of the bottom layer as we did in childhood. Then click “Save”-the B2P file at this time has the top and bottom layers of data.
6. Click “File” and “Export as PCB file”, you can get a PCB file with two layers of information, you can change the board or re-draw the schematic diagram or send it directly to the PCB plate making factory.
Multi-layer board copying method
In fact, the four-layer board copy board repeats copying two double-sided boards, the six-layer board repeats copying three double-sided boards … The reason why the multi-layer board is daunting is because we cannot see the internal wiring. A precise multi-layer board, how do we see its inner layer? -Layering.
There are many methods for layering, including potion corrosion, tool peeling, etc., but it is easy to over-layer and lose data. Experience tells us that sanding is the most accurate.
After we have copied the top and bottom layers of the PCB, we usually use sandpaper to grind off the surface layer to show the inner layer; sandpaper is the ordinary sandpaper sold by hardware stores, generally flatten the PCB, and then hold the sandpaper, rub evenly on the PCB (If the board is very small, you can also lay the sandpaper, use one finger to hold the PCB and rub it on the sandpaper). The point is to smooth it out so that it can be evenly ground.
The silk screen and the green oil are usually wiped off, and the copper wire and copper skin should be wiped a few times. Generally speaking, the Bluetooth board can be wiped in a few minutes, and the memory stick takes about ten minutes. Of course, it takes more time to spend more energy; less time to spend less energy.
Grinding plate is currently the most common solution for layering, and it is also the most economical. We can find an abandoned PCB to try. Actually, there is no technical difficulty in grinding the board, but it is a bit boring. It takes a little effort, and there is no need to worry about grinding the board to the finger.
In the PCB layout process, after the system layout is completed, the PCB diagram should be reviewed to see whether the system layout is reasonable and whether the best results can be achieved. Usually can be inspected from the following aspects:
1. Whether the system layout guarantees the reasonable or optimal wiring, whether it can guarantee the reliable operation of the wiring, and whether it can guarantee the reliability of the circuit work. In the layout, it is necessary to have an overall understanding and planning of the direction of the signal and the power supply and ground network.
2. Whether the size of the printed circuit board is consistent with the size of the processing drawings, whether it can meet the requirements of the PCB manufacturing process, and whether there is a behavior mark. This point needs special attention. The circuit layout and wiring of many PCB boards are beautifully designed and reasonable, but the precise positioning of the positioning connector is neglected, which makes the designed circuit unable to dock with other circuits.
3. Whether the components conflict in two-dimensional and three-dimensional spaces. Pay attention to the actual size of the device, especially the height of the device. When soldering layout-free components, the height should generally not exceed 3mm.
4. Whether the component layout is dense and orderly, arranged neatly, and whether they are all laid out. In the layout of components, not only the direction of the signal and the type of the signal, the places that need attention or protection, but also the overall density of the device layout should be considered 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 convenient and reliable to replace and plug components that are frequently replaced.