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 remove the components to make a bill of materials (BOM) and arrange material procurement. The scanned image is processed by the copy board software and restored to a pcb board drawing file, and then the PCB file is sent to the plate making factory for board making. After the board is made, the purchased components are welded to the made PCB board, and then the circuit board is tested. and debug it.
1. The specific steps of PCB copy board
1.1. When you get a PCB, first record the models, parameters, and positions of all the components on the paper, especially the direction of the diode and triode, and the direction of the IC gap. It is best to take two photos of the location of the vital parts with a digital camera. Today's pcb circuit boards are getting more and more advanced, and some of the diodes and triodes on it can't be seen if you don't pay attention.
1.2. Remove all multi-layer board parts and remove the tin in the PAD hole. Clean the PCB with alcohol, and then put it into the scanner. The scanner needs to increase the scanning pixels slightly to get a clearer image. Then lightly polish the top layer and the bottom layer with water 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.
1.3. Adjust the contrast and brightness of the canvas so that the contrast between the part with copper film and the part without copper film is strong, and then convert the next picture to black and white, check whether the lines are clear, if not, 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 any problem with the picture, you can use PHOTOSHOP to repair and correct it.
1.4. Convert the two BMP format files into PROTEL format files respectively, and transfer two layers into PROTEL. If the positions of PAD and VIA after the two layers basically overlap, it shows that the previous steps are done well. If there is any deviation , then repeat the third step. Therefore, pcb copy board is a job that requires patience, because a little problem will affect the quality and matching degree after copy board.
1.5. Convert the BMP of the TOP layer to TOP.PCB, pay attention to convert it to the SILK layer, which is the yellow layer, and then you just draw the line on the TOP layer, and place the device according to the drawing in the second step. Delete the SILK layer after drawing. Repeat until all layers are drawn.
1.6. Import TOP.PCB and BOT.PCB in PROTEL, and it is OK to combine them into one picture.
1.7. Use a laser printer to print the TOP LAYER and BOTTOM LAYER on the transparent film (1:1 ratio), put the film on the PCB, and compare whether there is any error. If it is correct, you are done.
A copy of the original board is born, but this is only half done. It is also necessary to test whether the electronic technical performance of the copy board is the same as that of the original board. If it's the same then it's really done.
If it is a multi-layer board, it must be carefully polished to the inner layer, and at the same time repeat the copying steps from the third to fifth steps. Of course, the names of the graphics are also different, and it depends on the number of layers. Laminates are much simpler, and multi-layer copy boards are prone to misalignment, so multi-layer copy boards must be particularly careful and careful (the internal conduction holes and non-conduction holes are prone to problems).
2. Double-sided copy board method
2.1. Scan the upper and lower surfaces of the circuit board and save two BMP pictures.
2.2. Open the copy board software Quickpcb2005, click "File" and "Open Base Map" 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 route... Just like a child tracing a picture, draw it once in this software, and click "Save" to generate a B2P file.
2.3. Click "File" and "Open Basemap" to open the scanned color map of another layer;
2.4. Click "File" and "Open" again to open the B2P file saved earlier, we can see the board just copied, stacked on top of this picture - the same PCB board, the hole is at the same position, but the wiring connection is different . So we press "Options" - "Layer Settings", here we turn off the lines and silkscreens showing the top layer, leaving only the multi-layer vias.
2.5. The vias on the top layer are in the same position as the vias on the bottom layer picture. Now we can just draw the bottom line as we did when we were children. Then click "Save" - the B2P file now has the top and bottom layers of data.
2.6. Click "File" and "Export as PCB File", you can get a PCB file with two layers of data, you can change the board or export the schematic diagram or send it directly to the PCB plate factory for production
3. The method of copying the multi-layer board In fact, the copying of the four-layer board is to copy two double-sided boards repeatedly, and the six-layer board is to copy three double-sided boards repeatedly. The reason why multi-layer boards are daunting is that we cannot see the internal movement Wire. How can we see the inner layer of a sophisticated multi-layer board? - layering.
There are many methods of layering, such as potion corrosion, knife stripping, etc., but it is easy to divide the layers too much and lose data. Experience tells us that sanding is the most accurate.
When we finish copying the top and bottom layers of the PCB, we usually use sandpaper to polish the surface to reveal the inner layer; the sandpaper is the ordinary sandpaper sold in hardware stores, and the PCB is usually tiled, and then press the sandpaper to rub evenly on the PCB (If the board is small, you can also lay sandpaper flat, hold the PCB with one finger and rub it on the sandpaper). The point is to lay it flat so that it can be ground evenly.
The silk screen and green oil are generally wiped off, and the copper wire and copper skin need to be wiped several times. Generally speaking, the bluetooth board can be wiped in a few minutes, and the memory stick takes about ten minutes; of course, if the strength is strong, it will take less time; if the strength is small, it will take a little longer.
Grinding plate is currently the most common solution for layering, and it is also the most economical. We can find a discarded PCB and try it out. In fact, there is no technical difficulty in grinding the board, but it is a bit boring and requires a little effort. Don't worry about grinding the board through and grinding your fingers.
During 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 optimal effect can be achieved. Usually, it can be investigated from the following aspects:
(1) Whether the system layout ensures the reasonable or optimal wiring, whether it can ensure the reliable wiring, and whether it can ensure the reliability of the circuit work. When laying out, it is necessary to have an overall understanding and planning of the direction of the signal and the power and ground network.
(2) Whether the size of the printed board is consistent with the size of the processing drawing, whether it meets the requirements of the PCB manufacturing process, and whether there is a behavior mark. This point requires special attention. The circuit layout and wiring of many PCB boards are designed beautifully and reasonably, but the precise positioning of the positioning connectors is neglected, resulting in the design of the circuit cannot be docked with other circuits.
(3) Whether there is any conflict between the components in two-dimensional and three-dimensional space. Note the physical dimensions of the device, especially the height of the device. When soldering layout-free components, the height generally cannot exceed 3mm.
(4) Whether the component layout is dense and orderly, neatly arranged, and whether all the layout is completed. When laying out components, not only the direction of the signal, the type of the signal, and the places that need attention or protection must be considered, but also the overall density of the device layout should be considered to achieve uniform density.
(5) Whether the components that need to be replaced frequently can be easily replaced, and whether the plug-in board can be inserted into the equipment is convenient. The convenience and reliability of replacement and insertion of frequently replaced components shall be ensured.
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