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Changing a set of Gerber files back into a single, editable PCB file is a job of rebuilding information. The goal is to take simple graphic files and give them intelligence again. We can easily convert Gerber files into PCB files by using the CAM tastic function in AItium Designer.
The whole idea is to use this tool as a special workspace where we can piece together the factory instructions and make the software understand the electrical connections and the physical structure of the board. This allows us to create a new PCB file that can be edited and used for future design work.
Making Sure You Have All the Files
Before any work can begin inside the software, the very first thing to do is to look at the files you have. A complete set of manufacturing files for a circuit board includes many different Gerber files. Each file describes one layer or one part of the board-making process.
You must check to make sure you have all the necessary pieces. If you are missing a key file, the final rebuilt PCB will be incomplete and will not be correct.
You will need the top copper layer file. This file shows all the copper lines, or traces, and the copper pads on the top side of the board. You will also need the bottom copper layer file. This shows all the copper on the bottom side. If the board has more than two layers, like a four-layer or six-layer board, you will need the Gerber files for all the inner copper layers as well.
Next, you need the solder mask files. There is usually a top solder mask file and a bottom solder mask file. The solder mask is the thin, protective coating, usually green, that covers the copper traces. The Gerber file for the solder mask shows where the openings in this coating should be, which is where parts will be soldered.
You will also need the silkscreen files. The silkscreen is the text and the component outlines printed on the board, usually in white ink. This helps people know where each part goes. There is a top silkscreen file and sometimes a bottom silkscreen file.
Finally, and this is very important, you need the drill file. This file is usually in a format called NC Drill. It is not a Gerber file, but it works with them. This file tells the drilling machine at the factory the exact location and size of every single hole on the board. These holes are used for component leads and for connecting different layers together.
Taking the time to gather all these files and put them in one folder is a very important first step. It makes the rest of the job much smoother and helps avoid problems later.
Making a New CAM File
Once you are sure you have all the needed files, you can open Altium Designer. The work of converting the files happens in a special kind of workspace. This workspace is called a CAM file. The word CAM means Computer-Aided Manufacturing. So, a CAM file is a place inside the design software that is made specifically to handle manufacturing files like Gerbers.
To create this workspace, you go to the menu at the top of the software. You click on “File,” then “New,” and then “CAM Document.” This will open a new, blank screen. This screen is your work area. It is different from the normal PCB editor.
It is built to understand and display the simple lines, shapes, and holes that are described in the Gerber and drill files. This is where you will bring all your separate factory files together to form a single picture of the board.
Loading the Gerber and Drill Files
With your empty CAM file ready, the next job is to load all of your manufacturing files into it. This is like putting all the pieces of a puzzle on a table before you start putting them together. This part of the process involves importing the Gerber files first, and then importing the drill file.
To import the Gerber files, you go to the “File” menu again. From there, you choose “Import,” and then you select an option called “Quick Load.” The Quick Load tool is helpful because it allows you to select all of your Gerber files at once.
Import and view the files
When you confirm the files, the software reads each one and shows them stacked in the CAM workspace. Each imported file becomes its own layer. This view helps you check how the pieces fit together.
Check the import log
After the import finishes, the program creates a log file with a .LOG extension. Open that log and read it. The log reports what happened during import. If a Gerber file had a format problem, the log will show a warning or an error. Reading the log tells you if all data loaded correctly.
Import the drill file
Next, import the drill file. Go to File > Import > Drill and pick your NC Drill file. The software then loads the drill file and shows every hole on the board. The holes appear aligned with the copper pads from the Gerber layers. Now you have a complete visual of the physical board in one place.
Quick check
Look over the layers and the log. Fix any warnings before you move on. This step helps avoid errors later.
Getting Net Information Out
The CAM document is merely a collection of images. The software does not know how these copper traces are connected to create a circuit; it only knows the locations of copper and vias. Extracting the net information, or “netlist,” is the next and most important step in the conversion process.
A circuit design’s “netlist,” or netlist, is its lifeblood. It specifies which wires and pads are electrically connected. Use the “Tools > Netlist > Extract” function to accomplish this. The program will automatically examine every copper pattern on the canvas after you run this command.
Each wire will be traced to determine which pads it connects to. Every copper pattern that is physically connected will be recognized as a single “net” and given a name automatically.
After completing this step, your design will become an intelligent circuit. The software will now understand the connections between the circuits. If you skip this step, the final PCB file will be nothing more than a drawing with a table.
Choosing the Layer Order
Several layers are stacked together to form a circuit board. Therefore, you must instruct the software on how these layers should be physically stacked before exporting a PCB file.
Navigate to the “Table > Layers” menu to accomplish this. You can check each imported layer here, for instance, to see which is the top copper layer and which is the top solder mask layer. Then, specify their physical arrangement using the “Table > Layer Order” function.
The layers in between should be arranged in accordance with the actual production order, with the top layer at the top and the bottom layer at the bottom. This arrangement is essential since it dictates the board’s ultimate structure. The exported PCB file will have significant problems in 3D previews or later production if the order is off.
Exporting to the PCB
The last step is to export this information-rich CAM document into a real PCB file after you’ve finished all the data reconstruction procedures mentioned above.
All you have to do is choose “File > Export > Export to PCB.” All of your work, including graphics, nets, and layer structure, will be packaged by the software into a new PCB document (.PcbDoc).
You’ll discover that you’re in a typical PCB design environment instead of a CAM editing environment when you open this new file. Traces, pads, and vias will be visible to you; clicking on a trace will highlight all of its connected components. This attests to your successful reconstruction of the design.
