Introduction to Gerber and Gerber X2 Formats

Gerber files are the industry standard for PCB (Printed Circuit Board) design and manufacturing. They contain all the necessary information required to fabricate a PCB, including the copper layers, solder mask, silk screen, and drill data. There are two main types of Gerber files: traditional Gerber (also known as RS-274X) and the newer Gerber X2 format.

What are Traditional Gerber (RS-274X) Files?

Traditional Gerber files, also referred to as RS-274X, have been the standard format for PCB manufacturing since the 1980s. They are ASCII text files that describe the different layers and features of a PCB using a series of commands and coordinates. Each file represents a single layer of the PCB, such as the top copper layer, bottom copper layer, or solder mask.

Advantages of Traditional Gerber Files

• Widely supported by PCB design software and manufacturers
• Simple and easy to generate
• Compact file size

Disadvantages of Traditional Gerber Files

• Limited metadata and lack of design intent information
• Potential for ambiguity and misinterpretation
• Requires additional files for drill data and netlist information

What are Gerber X2 Files?

Gerber X2 is an extension of the traditional Gerber format, introduced by Ucamco in 2014. It builds upon the RS-274X format by adding additional metadata and design intent information, making the files more intelligent and self-contained. Gerber X2 files use the same file extension as traditional Gerber files (.gbr), but they include enhanced features and attributes.

Advantages of Gerber X2 Files

• Embedded metadata and design intent information
• Reduces ambiguity and potential for misinterpretation
• Includes drill data and netlist information within the same file
• Supports advanced features like embedded components and rigid-Flex Designs

Disadvantages of Gerber X2 Files

• Not as widely supported as traditional Gerber files (yet)
• Slightly larger file size due to additional metadata

Key Differences Between Gerber and Gerber X2 Files

Feature	Traditional Gerber (RS-274X)	Gerber X2
File Extension	.gbr	.gbr
Metadata	Limited	Extensive
Design Intent	Not included	Included
Drill Data	Separate file	Embedded
Netlist Information	Separate file	Embedded
Advanced Features	Not supported	Supported
File Size	Compact	Slightly larger
Compatibility	Widely supported	Growing support

Metadata and Design Intent

One of the main differences between traditional Gerber and Gerber X2 files is the inclusion of metadata and design intent information. Gerber X2 files contain additional attributes that provide context and meaning to the PCB data, such as:

• Layer types (copper, solder mask, silk screen, etc.)
• Pad functions (SMD, through-hole, via, etc.)
• Net names and network information
• Component names and references
• Fabrication and assembly notes

This extra information helps to clarify the designer’s intent and reduces the potential for misinterpretation during the manufacturing process.

Drill Data and Netlist Information

In traditional Gerber files, drill data and netlist information are typically provided as separate files (e.g., Excellon drill files and IPC-D-356 netlist files). This can lead to issues with file management and version control, as well as potential discrepancies between the various files.

Gerber X2 addresses this problem by embedding the drill data and netlist information directly within the Gerber files. This ensures that all the necessary data is contained within a single file, making it easier to manage and reducing the risk of errors.

Advanced Features and Compatibility

Gerber X2 supports advanced PCB design features that are not possible with traditional Gerber files, such as:

• Embedded components (components placed within the PCB substrate)
• Rigid-flex designs (PCBs with both rigid and flexible sections)
• Complex pad shapes and custom apertures
• Filled areas with varying fill patterns

While these features are becoming increasingly important in modern PCB designs, not all PCB design software and manufacturers fully support Gerber X2 yet. However, the adoption of Gerber X2 is growing rapidly, and it is expected to become the new industry standard in the near future.

Best Practices for Working with Gerber and Gerber X2 Files

Regardless of whether you are working with traditional Gerber or Gerber X2 files, there are several best practices you should follow to ensure smooth communication with your PCB manufacturer and minimize the risk of errors:

1. Use a consistent naming convention for your Gerber files, such as the IPC-D-326 standard.
2. Include a README file or fabrication notes that provide additional information about your design, such as the PCB thickness, copper weight, and any special requirements.
3. Verify your Gerber files using a Gerber viewer or DFM (Design for Manufacturability) tool before sending them to your manufacturer.
4. Communicate with your PCB manufacturer to ensure they support the Gerber format you are using and to clarify any questions or concerns.

Gerber File Naming Convention (IPC-D-326)

The IPC-D-326 standard provides a recommended naming convention for Gerber files to ensure consistency and clarity. The basic format is as follows:

ProjectName_LayerName_FileFunction.gbr

For example:

• MyProject_Top_Copper.gbr
• MyProject_Bottom_SolderMask.gbr
• MyProject_Drill_PTH.gbr

Using a standardized naming convention helps to avoid confusion and ensures that your PCB manufacturer can easily identify the purpose of each file.

Verifying Gerber Files

Before sending your Gerber files to a PCB manufacturer, it is essential to verify them using a Gerber viewer or DFM tool. These tools allow you to visually inspect your PCB design and check for potential issues, such as:

• Incorrect layer alignment
• Missing or overlapping features
• Insufficient clearances or spacing
• Unsuitable hole sizes or pad geometries

Many PCB design software packages include built-in Gerber viewers, but there are also standalone tools available, such as GC-Prevue, ViewMate, and CAM350.

FAQ

1. Can I use both traditional Gerber and Gerber X2 files in the same PCB project?

While it is technically possible to mix traditional Gerber and Gerber X2 files in the same project, it is not recommended. It is best to use one format consistently throughout your design to avoid potential compatibility issues and ensure clear communication with your PCB manufacturer.

2. Do I need to update my PCB design software to work with Gerber X2 files?

Many modern PCB design software packages support Gerber X2 files, either natively or through updates. However, some older software may not have full Gerber X2 support. Check with your software vendor to determine if an update is necessary or if there are any limitations in working with Gerber X2 files.

3. Will using Gerber X2 files increase my PCB manufacturing costs?

In most cases, using Gerber X2 files will not directly impact your PCB manufacturing costs. However, if your design includes advanced features that are only supported by Gerber X2, such as embedded components or rigid-flex sections, there may be additional costs associated with those specific features.

4. How can I convert my existing traditional Gerber files to Gerber X2 format?

Some PCB design software packages include tools for converting traditional Gerber files to Gerber X2 format. Alternatively, you can use a standalone Gerber editing tool, such as Ucamco’s free GerberConvert utility, to perform the conversion. However, it is important to review the converted files carefully to ensure no data is lost or misinterpreted during the process.

5. Are there any specific requirements for generating Gerber X2 files?

To generate Gerber X2 files correctly, your PCB design software must support the Gerber X2 format and be configured to output files with the necessary attributes and metadata. Consult your software documentation or vendor support for specific instructions on generating Gerber X2 files from your design.

Conclusion

Understanding the differences between traditional Gerber and Gerber X2 files is essential for anyone involved in PCB design and manufacturing. While traditional Gerber files have been the industry standard for decades, Gerber X2 offers significant advantages in terms of metadata, design intent, and advanced feature support.

As the adoption of Gerber X2 continues to grow, PCB designers and manufacturers should familiarize themselves with this new format and its benefits. By following best practices and maintaining clear communication, the transition from traditional Gerber to Gerber X2 can be a smooth and rewarding process, ultimately leading to higher quality PCBs and more efficient manufacturing workflows.