Introduction to PCB editing and Gerber Files

Printed Circuit Board (PCB) design and manufacturing is a crucial aspect of electronic product development. PCB editing involves modifying an existing PCB design to improve its functionality, performance, or to correct any errors. Gerber files, on the other hand, are the industry standard for PCB fabrication. They contain all the necessary information required to manufacture a PCB, including the copper layers, solder mask, silkscreen, and drill data.

In this article, we will explore the possibility of editing a new PCB using a Gerber file as a background in Altium Designer, a popular PCB design software. We will discuss the benefits and challenges of this approach and provide step-by-step instructions on how to achieve it.

What are Gerber Files?

Gerber files are a set of files that contain all the necessary information required to fabricate a PCB. They are named after the Gerber Systems Corp., the company that developed the format in the 1960s. Gerber files are now an industry standard and are widely used by PCB manufacturers worldwide.

A typical set of Gerber files includes:

• Copper layers (e.g., top and bottom layers)
• Solder mask layers
• Silkscreen layers
• Drill data

Each layer is represented by a separate file, and the file extension indicates the layer type. For example, a top copper layer might have a file extension of “.GTL” (Gerber Top Layer).

Advantages of Using Gerber Files

Using Gerber files for PCB fabrication has several advantages:

1. Universality: Gerber files are widely accepted by PCB manufacturers worldwide, making it easy to switch between different fabrication houses if needed.

2. Reliability: Gerber files contain all the necessary information required to fabricate a PCB, reducing the chances of errors or misinterpretation.

3. Compatibility: Most PCB design software, including Altium Designer, can generate and import Gerber files, ensuring seamless integration between design and manufacturing.

Limitations of Gerber Files

Despite their widespread use, Gerber files have some limitations:

1. Lack of intelligence: Gerber files are essentially a set of coordinates and shapes that represent the PCB layers. They do not contain any information about the components, nets, or design rules, making it difficult to modify the design without access to the original PCB design files.

2. Potential for errors: If the Gerber files are generated incorrectly or are not properly checked before fabrication, it can lead to costly manufacturing errors.

Editing a New PCB Using a Gerber File as Background in Altium Designer

Altium Designer is a powerful PCB design software that offers a wide range of features and tools for creating high-quality PCB designs. One of its features is the ability to import Gerber files and use them as a background for editing a new PCB design.

Benefits of Using Gerber Files as Background in Altium Designer

Using Gerber files as a background in Altium Designer has several benefits:

1. Referencing existing designs: By importing a Gerber file as a background, you can easily reference an existing PCB design while creating a new one. This can be particularly useful when designing a new version of an existing product or when creating a compatible design.

2. Ensuring compatibility: Using a Gerber file as a background allows you to ensure that your new design is compatible with the existing one, reducing the chances of errors or inconsistencies.

3. Saving time: By using a Gerber file as a starting point, you can save time and effort in recreating the basic structure of the PCB, such as the board outline and mounting holes.

Challenges of Using Gerber Files as Background in Altium Designer

While using Gerber files as a background in Altium Designer has its benefits, there are also some challenges to consider:

1. Limited editability: As mentioned earlier, Gerber files do not contain any intelligence about the components, nets, or design rules. This means that while you can use them as a reference, you cannot directly edit the imported Gerber data.

2. Potential for errors: If the Gerber files are not properly aligned or scaled, it can lead to errors in the new design. It is important to ensure that the Gerber files are imported correctly and are properly aligned with the new design.

Step-by-Step Guide to Editing a New PCB Using a Gerber File as Background in Altium Designer

Follow these steps to edit a new PCB using a Gerber file as a background in Altium Designer:

1. Import the Gerber files: In Altium Designer, go to “File” > “Import” > “Gerber Files.” Select the Gerber files you want to import and click “Open.” The Gerber files will be imported as a new PCB document.

2. Create a new PCB document: Go to “File” > “New” > “PCB” to create a new PCB document.

3. Set the Gerber files as background: In the new PCB document, go to “View” > “Layers” to open the Layers panel. Right-click on the “Mechanical 1” layer and select “Layer Stack Manager.” In the Layer Stack Manager, click on the “Mechanical 1” layer and then click on the “Background” checkbox. Click “OK” to close the Layer Stack Manager.

4. Align the Gerber background: Use the “Move” and “Rotate” tools in the PCB editor to align the Gerber background with the new PCB document. Ensure that the board outline and any key features, such as mounting holes, are properly aligned.

5. Design the new PCB: With the Gerber background in place, you can now proceed to design the new PCB. Use the Gerber background as a reference to ensure compatibility with the existing design. Add components, route traces, and define design rules as needed.

6. Verify the design: Once the new PCB design is complete, use Altium Designer’s design rule checking (DRC) and electrical rule checking (ERC) tools to verify the design for any errors or violations.

7. Generate output files: After the design is verified, generate the necessary output files, such as Gerber files and drill files, for fabrication.

Best Practices for Using Gerber Files as Background in Altium Designer

To ensure the best results when using Gerber files as a background in Altium Designer, follow these best practices:

1. Use high-quality Gerber files: Ensure that the Gerber files you use as a background are of high quality and are free from errors. Verify the files before importing them into Altium Designer.

2. Properly align the Gerber background: Take the time to properly align the Gerber background with the new PCB document. Use the board outline and key features as reference points for alignment.

3. Double-check the design: After completing the new PCB design, thoroughly check it for any errors or inconsistencies. Use Altium Designer’s DRC and ERC tools to verify the design.

4. Communicate with the fabrication house: When sending the output files for fabrication, communicate clearly with the fabrication house about any specific requirements or considerations. Provide them with the original Gerber files used as a background for reference.

Frequently Asked Questions (FAQ)

1. Can I edit the imported Gerber data directly in Altium Designer?
   No, the imported Gerber data is used only as a background reference and cannot be directly edited in Altium Designer. You can use it as a guide to create a new PCB design.

2. What if the Gerber files are not properly aligned with the new PCB document?
   If the Gerber files are not properly aligned, use the “Move” and “Rotate” tools in the PCB editor to adjust their position and orientation. Ensure that the board outline and key features are properly aligned before proceeding with the new design.

3. Can I use Gerber files from any PCB design software as a background in Altium Designer?
   Yes, Gerber files are an industry standard and can be generated by most PCB design software. As long as the Gerber files are of high quality and free from errors, you can use them as a background in Altium Designer.

4. What if I need to make changes to the original Gerber files?
   If you need to make changes to the original Gerber files, you will need to edit the original PCB design files and regenerate the Gerber files. Alternatively, you can use the Gerber files as a reference to create a new PCB design and make the necessary changes there.

5. Can I use multiple Gerber files as background layers in Altium Designer?
   Yes, you can import multiple Gerber files and set them as background layers in Altium Designer. This can be useful when working with complex designs or when you need to reference multiple layers of an existing PCB.

Conclusion

In this article, we explored the possibility of editing a new PCB using a Gerber file as a background in Altium Designer. We discussed the benefits and challenges of this approach and provided a step-by-step guide on how to achieve it.

Using Gerber files as a background in Altium Designer can be a valuable technique for referencing existing designs, ensuring compatibility, and saving time. However, it is important to be aware of the limitations of Gerber files and to follow best practices to ensure the best results.

By properly aligning the Gerber background, thoroughly checking the new design, and communicating clearly with the fabrication house, you can successfully edit a new PCB using a Gerber file as a background in Altium Designer.