How do I open a PCB Gerber file?

What are Gerber files in PCB design?

Gerber files are the standard file format used in the PCB (Printed Circuit Board) industry for designing and manufacturing electronic circuits. They contain all the necessary information required to fabricate a PCB, including the copper layers, solder mask, silkscreen, and drill data. Gerber files are named after their creator, H. Joseph Gerber, who developed the format in the 1960s.

Components of a Gerber file

A typical set of Gerber files for a PCB includes:

  1. Top and bottom copper layers (.gtl and .gbl)
  2. Top and bottom solder mask layers (.gts and .gbs)
  3. Top and bottom silkscreen layers (.gto and .gbo)
  4. Drill data file (.drl or .txt)
  5. Outline layer (.gm1 or .gko)
  6. Pastemask layers (.gtp and .gbp), if required

Each layer is represented by a separate Gerber file, and the file extension indicates the layer type.

How to open Gerber files

To open and view Gerber files, you need a Gerber viewer software. There are several options available, both free and paid. Some popular Gerber viewers include:

  1. Gerbv (free, open-source)
  2. ViewMate (free)
  3. CAM350 (paid)
  4. GC-Prevue (paid)
  5. Ucamco UcamX (paid)

Opening Gerber files in Gerbv

Gerbv is a free, open-source Gerber viewer that runs on Windows, macOS, and Linux. To open Gerber files in Gerbv:

  1. Download and install Gerbv from the official website (http://gerbv.geda-project.org/).
  2. Launch the Gerbv application.
  3. Click on “File” > “Open Layer” or press Ctrl+O.
  4. Navigate to the folder containing your Gerber files and select the files you want to open. You can select multiple files by holding down the Ctrl key while clicking on the files.
  5. Click “Open” to load the selected Gerber files into Gerbv.

Once the files are loaded, you can view the PCB design, zoom in and out, and toggle the visibility of individual layers.

Opening Gerber files in ViewMate

ViewMate is another free Gerber viewer, available for Windows. To open Gerber files in ViewMate:

  1. Download ViewMate from the official website (https://www.pentalogix.com/viewmate-downloads).
  2. Install and launch ViewMate.
  3. Click on “File” > “Load Files” or press Ctrl+L.
  4. Select the Gerber files you want to open and click “Open.”
  5. ViewMate will load and display the PCB design.

Similar to Gerbv, you can navigate the design, zoom, and control layer visibility in ViewMate.

Interpreting Gerber files

Once you have opened your Gerber files in a viewer, it’s essential to understand what you are seeing. Here are some key aspects to look for:

  1. Board outline: Check if the board outline is correct and matches your design.
  2. Copper layers: Verify that the copper traces and pads are properly positioned and connected.
  3. Solder mask: Ensure that the solder mask openings align with the pads and exposed copper areas.
  4. Silkscreen: Check the placement and legibility of component labels and other text.
  5. Drill holes: Confirm that the drill holes are correctly positioned and sized.

By carefully examining each layer, you can catch any errors or discrepancies before sending your files for manufacturing.

Common issues with Gerber files

While working with Gerber files, you may encounter some common issues:

  1. Missing layers: Ensure that you have exported all the necessary layers from your PCB design software.
  2. Incorrect file extensions: Make sure that the file extensions match the layer types (e.g., .gtl for top copper layer).
  3. Incorrect units: Gerber files can be in either metric (mm) or imperial (inches) units. Confirm that your files use the correct units and match your manufacturer’s requirements.
  4. Aperture list discrepancies: Check that the aperture list in your Gerber files matches the one used in your design software.
  5. Overlapping or missing features: Verify that there are no overlapping or missing traces, pads, or other features in your design.

By addressing these issues before submitting your files for manufacturing, you can minimize the risk of production delays and additional costs.

Best practices for creating Gerber files

To ensure that your Gerber files are accurate and ready for manufacturing, follow these best practices:

  1. Use a reliable PCB design software: Choose a reputable PCB design software that can generate high-quality Gerber files, such as Altium Designer, KiCad, or Eagle.
  2. Follow your manufacturer’s guidelines: Consult your PCB manufacturer’s documentation for their specific Gerber file requirements, such as file naming conventions, layer order, and minimum feature sizes.
  3. Include all necessary layers: Export all the required layers for your PCB, including copper, solder mask, silkscreen, and drill data.
  4. Use a consistent units: Ensure that all your Gerber files use the same units (metric or imperial) and match your manufacturer’s preferences.
  5. Verify your design: Before exporting Gerber files, thoroughly check your PCB design for errors, such as unconnected traces, overlapping components, or violation of design rules.
  6. Generate a Gerber job file: Create a Gerber job file (.gbrjob) that includes all the necessary Gerber files and drill data in one package for easy transfer to your manufacturer.
  7. Review your Gerber files: Always open and review your Gerber files in a Gerber viewer before submitting them for manufacturing to catch any errors or discrepancies.

By adhering to these best practices, you can minimize the risk of manufacturing issues and ensure a smooth PCB production process.

FAQ

  1. What is the difference between Gerber files and ODB++ files?
    Gerber files are the standard file format for PCB manufacturing, containing individual files for each layer of the PCB. ODB++ (Open Database Plus Plus) is a more comprehensive file format that includes all the PCB design data in a single, unified database. ODB++ files can include additional information like component placement and netlist data, making them more suitable for advanced pcb assembly processes.

  2. Can I edit Gerber files?
    Gerber files are not meant to be edited directly. If you need to make changes to your PCB design, it’s best to modify the design in your PCB design software and then generate new Gerber files. However, some advanced PCB design tools, like Ucamco’s UcamX, do allow for limited editing of Gerber files.

  3. What should I do if my manufacturer reports issues with my Gerber files?
    If your PCB manufacturer reports problems with your Gerber files, first ask for a detailed description of the issues. Then, review your files in a Gerber viewer, comparing them to your original design. If necessary, make corrections in your PCB design software and generate new Gerber files. Always communicate closely with your manufacturer to resolve any concerns.

  4. Can I view Gerber files without specialized software?
    While it’s possible to open Gerber files in a text editor, they will appear as unreadable code. To properly view and interpret Gerber files, you need a dedicated Gerber viewer software. Many Gerber viewers are available for free, such as Gerbv and ViewMate, making it easy to access and review your PCB design files.

  5. How do I choose the right Gerber file format for my project?
    The most common Gerber file format is RS-274X, also known as Extended Gerber or X-Gerber. This format is widely supported by PCB manufacturers and design software. When in doubt, consult your PCB manufacturer’s guidelines for their preferred Gerber file format and settings. By using the format recommended by your manufacturer, you can ensure compatibility and minimize the risk of production delays.

Layer Type File Extension
Top Copper .gtl
Bottom Copper .gbl
Top Solder Mask .gts
Bottom Solder Mask .gbs
Top Silkscreen .gto
Bottom Silkscreen .gbo
Drill Data .drl or .txt
Outline .gm1 or .gko
Top Paste Mask .gtp
Bottom Paste Mask .gbp

In conclusion, understanding how to open and interpret Gerber files is crucial for anyone involved in PCB design and manufacturing. By using a reliable Gerber viewer, following best practices for creating Gerber files, and communicating effectively with your PCB manufacturer, you can ensure that your PCB design is accurately translated into a physical product. With the knowledge and tools covered in this article, you’ll be well-equipped to navigate the world of Gerber files and bring your pcb projects to life.