What are the Differences in the Copying Methods of Double-Sided and Multi-Layer PCBs?

The technical realization of PCB copying is as simple as scanning the circuit board to be copied, recording the precise component positions, removing the components to create a bill of materials (BOM) and arrange for material procurement, and then sending the empty board to the plate manufacturing factory with the PCB file for production. After the PCB board is created, the purchased components are welded to it. The circuit board and debugging are then tested.

Ⅰ.  The specific steps of PCB copying

1. Obtain a PCB, then write down the models, parameters, and locations of all the important components on the paper, paying particular attention to the direction of the diodes, triodes, and IC notch. It is advisable to use a digital camera to snap two images of the element's location. The sophistication of PCB circuit boards today is increasing. Some of the aforementioned diodes and triodes cannot be seen at all.

2. Take out the tin from the PAD hole and all of the multi-layer board components. After cleaning the PCB with alcohol, place it in the scanner. To produce a crisper image during scanning, the scanner needs to slightly increase the scanned pixels. Once the copper film is shiny, lightly buff the top and bottom layers with wet gauze paper, place them in the scanner, launch PHOTOSHOP, and scan the two layers in color. Remember that for the scanned image to be available, the PCB must be positioned both horizontally and vertically in the scanner.

3. Change the second image to black and white and make sure the lines are apparent. If not, repeat steps 3 and 4 to adjust the canvas's contrast and brightness such that the area covered with copper film and the area that isn't have a strong contrast. If it is obvious that the images were saved as the files TOP.BMP and BOT.BMP in the BMP format, if you find any problems with the graphics, you can also use PHOTOSHOP to repair and correct them.

4. Transfer two levels in PROTEL from the two BMP format files into their corresponding PROTEL format files. For instance, the positions of PAD and VIA after the two layers are nearly identical, demonstrating the effectiveness of the initial procedures. The third step should be repeated if there is any variance. Therefore, PCB copying is a task that requires patience because even a minor issue will have an impact on the copy's quality and degree of matching.

5. Change the TOP layer's BMP to TOP.

PCB, be sure to change it to the SILK layer (the yellow layer), after which you can draw a line on the TOP layer and, in the following step, position the device in accordance with the drawing. After drawing, delete the SILK layer, and repeat until all layers are drawn.

6. Import TOP.PCB and BOT.PCB into PROTEL and merge them into a single image.

7. Print the TOP LAYER and BOTTOM LAYER on the transparencies in a 1:1 ratio using a laser printer, then place the film on the PCB and check for errors. Upon confirmation, you are done.

A duplicate of the original board was created, however it was incomplete. Testing is also required to see if the clone board's electronic technical performance is identical to that of the original board. If so, it is effectively finished.

Remarks: If the board has multiple layers, it should be properly polished down to the inner layer while also copying the third through fifth processes. Of course, the names given to the graphics vary as well, and they should be chosen based on the number of layers. The double-sided board should typically be replicated. The multi-layer copy board should be extremely cautious and meticulous because it is much simpler than the multi-layer board and the multi-layer copy board is prone to improper alignment (the internal vias and non-conductive holes are prone to problems).

Ⅱ.  Double-sided copying method

1. Scan the circuit board's upper and lower layers, then save two BMP images.

2. Launch Quickpcb2005, select "File," and then "Open Basemap" to open a scanned image. In order to see the pad, insert a pad by pressing PP, observe the line, and route, use PAGEUP to magnify the screen. Draw it again in this program like a kid would, then click "Save" to create a B2P file.

3. To view the scanned color image of a different layer, select "File" and "Open Basemap";

Figure. 1

4. To open the B2P file previously saved, once again click "File" and "Open." The freshly duplicated board is shown layered on top of this image; it is the same PCB board; the holes are in the same locations; however, the circuit connections are different. In order to just see the multi-layer vias, we disable the lines and silkscreens that reveal the top layer by selecting "Options" - "Layer Settings."

5.The vias on the top layer and the bottom layer image are both in the same location. We can once again trace the base layer like we did when we were younger. Once more, click "Save" to add the top and bottom layers of data to the B2P file.

6. Click "File" and "Export as PCB File", you can get a PCB file with two layers of data, you can re-modify the board or re-print the schematic diagram or send it directly to the PCB plate-making factory for production.

Ⅲ.  Multilayer board copying method

A four-layer board can really be copied by using two double-sided boards, while a six-layer board can be copied by using three double-sided boards. The fact that we cannot see the internal circuitry makes numerous layers intimidating. How do we see the inner layers of a precision multi-layer board? – Layered

There are numerous methods for layering already, such as knife peeling and potion corrosion, however it is simple to divide the layers too much and lose data. We know from experience that sanding is the most precise.

After copying the top and bottom layers of the PCB, we often use sandpaper to remove the outer layer and reveal the inner layer. The PCB is typically laid out on a flat surface before the sandpaper is applied, rubbing the PCB evenly (If the board is small, you can also lay the sandpaper flat, hold the PCB with one finger and rub it on the sandpaper). In order for it to grind evenly, the object is to flatten.

The copper wire and copper skin should be repeatedly cleansed once the silk screen and green oil have been removed. Generally speaking, wiping the Bluetooth board only takes a few minutes, and wiping the memory stick takes around ten minutes. Of course, depending on your strength, it may take less time or a bit longer.

The most popular and affordable method of layering at the moment is grinding. We can look for an unused PCB. Although technically not difficult, grinding the board is a little monotonous. There is no need to worry about wearing the board into your fingertips; it just takes a little work.

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 it can achieve the optimal effect.

Figure. 2

It can usually be investigated from the following aspects:

1. Whether the system layout can guarantee that the wiring is reasonable or ideal, whether it can guarantee that the wiring will operate reliably, and whether it can guarantee that the circuit will operate reliably. The direction of the signal as well as the power and ground network must be understood and planned for generally during the architecture.

2. Whether the printed board's dimensions match those of the processing drawing, whether it can satisfy the conditions of PCB manufacture, and whether a behavior mark is there. This issue need special consideration. Many PCB boards' circuit layouts and wirings are elegantly and sensibly constructed, but the proper positioning of the positioning connection is often overlooked, making it impossible for the specified circuit to be connected to other circuits.

3.The degree of incompatibility between elements in two- and three-dimensional space. Pay close attention to the device's real dimensions, particularly its height. The height typically cannot be greater than 3mm when soldering layout-free components.

4. The density and organization of the component layout, the neatness with which it is structured, and the completion of all layouts. When arranging components, it is important to take into account the overall density of the device layout so that the density is consistent, as well as the signal's direction, kind, and vulnerable locations.

5.Whether the plug-in board can be conveniently put into the device and whether the often replaced components can be simply replaced. The ease and dependability of the replacement and connection of the frequently replaced components should be guaranteed.