Gerber files are the industry standard for PCB manufacturing, serving as the digital blueprint that manufacturers use to fabricate printed circuit boards. These files contain all the critical information needed for PCB production, including copper layers, solder mask, drill data, and assembly information. Altium Designer, one of the most powerful PCB design software tools available, provides comprehensive capabilities for generating high-quality Gerber files that meet manufacturing specifications.
Understanding how to properly export Gerber files from Altium PCB is essential for any PCB designer, as improper file generation can lead to manufacturing errors, delays, and increased costs. This comprehensive guide will walk you through every aspect of the Gerber export process, from basic setup to advanced configuration options, ensuring your designs are manufacturing-ready.
Understanding Gerber Files and Their Importance in PCB Manufacturing
Gerber files, named after the Gerber Scientific Corporation that developed the format, are vector-based files that describe the copper features, drill holes, and other physical characteristics of a PCB. The modern Extended Gerber format (RS-274X) is the current industry standard, providing enhanced capabilities over the legacy RS-274D format.
Each Gerber file represents a single layer or aspect of the PCB design. A typical PCB project generates multiple Gerber files, including copper layers, solder mask layers, paste mask layers, drill files, and pick and place files. The precision and accuracy of these files directly impact the quality and functionality of the final manufactured PCB.
Key Components of a Complete Gerber File Set
A professional Gerber file package typically includes the following components:
| File Type | Extension | Purpose | Critical for Manufacturing |
|---|---|---|---|
| Copper Layers | .GTL, .GBL, .G1, .G2 | Define conductive traces and pads | Yes |
| Solder Mask | .GTS, .GBS | Define solder mask openings | Yes |
| Paste Mask | .GTP, .GBP | Define solder paste application | For SMT assembly |
| Drill Files | .TXT, .DRL | Define hole locations and sizes | Yes |
| Pick and Place | .CSV, .TXT | Component placement data | For assembly |
| Aperture List | .REP | Aperture definitions and usage | Documentation |
Preparing Your Altium PCB Design for Gerber Export
Before generating Gerber files, it's crucial to ensure your PCB design is complete and properly configured. This preparation phase significantly impacts the quality and manufacturability of your final Gerber output.
Design Rule Check (DRC) Verification
Running a comprehensive Design Rule Check is the first critical step before Gerber export. The DRC identifies potential manufacturing issues, design violations, and errors that could cause problems during fabrication.
To perform a DRC in Altium Designer:
- Navigate to Tools → Design Rule Check
- Configure the DRC settings to match your manufacturer's capabilities
- Run the check and resolve all violations
- Pay special attention to minimum trace width, via sizes, and spacing requirements
Layer Stack-Up Configuration
Proper layer stack-up configuration ensures that your Gerber files accurately represent the intended PCB structure. This is particularly important for multi-layer designs where layer ordering and thickness specifications are critical.
Key considerations for layer stack-up:
- Verify layer names and types are correctly assigned
- Confirm dielectric thickness and material specifications
- Ensure proper impedance control layer identification
- Validate via span definitions for buried and blind vias
Component and Net Verification
Before generating manufacturing files, verify that all components are properly placed and all nets are correctly routed:
- Check for unconnected nets or floating pins
- Verify component orientations and polarities
- Ensure all components have valid footprints
- Confirm that no components extend beyond board boundaries
Step-by-Step Guide to Exporting Gerber Files from Altium Designer
The Gerber export process in Altium Designer involves several stages, each requiring careful attention to settings and parameters. This section provides a detailed walkthrough of the complete export procedure.
Accessing the CAM Editor
Altium Designer uses the CAM (Computer-Aided Manufacturing) Editor for generating manufacturing files. The CAM Editor provides comprehensive control over file generation parameters and output formats.
To access the CAM Editor:
- Open your completed PCB design in Altium Designer
- Navigate to File → Fabrication Outputs → Gerber Files
- The CAM Editor will open, displaying the Gerber Setup dialog
Configuring Gerber Export Settings
The Gerber Setup dialog contains numerous configuration options that control the format, precision, and content of your output files. Understanding these settings is crucial for generating manufacturer-compatible files.
General Settings Configuration
The General tab contains fundamental settings that apply to all generated Gerber files:
| Setting | Recommended Value | Purpose |
|---|---|---|
| Format | RS-274X (Extended Gerber) | Modern industry standard |
| Units | Millimeters | Metric preferred by most manufacturers |
| Precision | 4.6 (4 integer, 6 decimal) | High precision for accurate reproduction |
| Zero Suppression | Leading | Standard format convention |
| Coordinate Format | Absolute | Precise positioning |
Advanced Settings Configuration
The Advanced tab provides additional control over file generation:
- Film Size: Set to match your PCB dimensions with appropriate margins
- Mirror Layers: Generally disabled unless specifically required
- Plot Positive: Standard setting for most applications
- Include Unconnected Mid-Layer Pads: Disable to reduce file size and complexity
Layer Configuration and Selection
Proper layer configuration ensures that all necessary PCB layers are included in the Gerber export while excluding unnecessary or problematic layers.
Copper Layer Configuration
For copper layers, configure the following settings:
- Top Copper (Top Layer): Always include for surface routing
- Bottom Copper (Bottom Layer): Include for double-sided or multi-layer boards
- Internal Layers: Include all used internal copper layers
- Power Planes: Configure as negative or positive based on design requirements
Non-Copper Layer Configuration
Non-copper layers require specific attention to ensure proper manufacturing interpretation:
| Layer Type | Configuration Notes |
|---|---|
| Top Solder Mask | Include openings for pads and vias |
| Bottom Solder Mask | Mirror of top mask for bottom layer |
| Top Paste Mask | Required for SMT assembly |
| Bottom Paste Mask | Include if bottom-side SMT components exist |
| Silkscreen | Include component designators and alignment marks |
Drill File Configuration
Drill files contain critical information about hole locations, sizes, and types. Proper drill file configuration ensures accurate hole placement during manufacturing.
Excellon Drill File Settings
Configure drill files with the following parameters:
- Format: Excellon format (industry standard)
- Units: Match Gerber file units (millimeters recommended)
- Precision: 3.3 format (3 integer, 3 decimal places)
- Zero Suppression: Leading zeros suppressed
- Coordinate Origin: Absolute coordinates
Drill File Content Options
Select appropriate content options for your drill files:
- Plated Holes: Include all plated through-holes and vias
- Non-Plated Holes: Include mounting holes and tooling holes
- Blind/Buried Vias: Include if present in design
- Micro Vias: Include if used (HDI designs)
Advanced Gerber Export Configurations
Advanced users often require specialized Gerber configurations to meet specific manufacturing requirements or to optimize files for particular fabrication processes.
Multi-Board Panel Configurations
When designing panels containing multiple PCBs, special considerations apply to Gerber export:
- Panel vs. Individual Board Export: Decide whether to export the entire panel or individual boards
- Tooling Hole Management: Include panel tooling holes in drill files
- Fiducial Marker Placement: Ensure fiducials are properly positioned for assembly
- V-Score and Tab Routing: Include mechanical layer information for depaneling
HDI (High Density Interconnect) Considerations
HDI designs with blind vias, buried vias, and micro vias require special attention during Gerber export:
Micro Via Configuration
| Parameter | Setting | Justification |
|---|---|---|
| Via Type Definition | Separate drill files | Different drill processes required |
| Layer Span Documentation | Include via span reports | Manufacturing process planning |
| Aspect Ratio Verification | Check manufacturer limits | Ensure manufacturability |
Impedance Control Documentation
For designs requiring controlled impedance, include additional documentation:
- Layer stack-up specifications
- Impedance requirements per net class
- Test coupon locations and configurations
- Dielectric constant and thickness specifications
Quality Assurance and File Verification
Generating Gerber files is only part of the process; thorough verification ensures that the files accurately represent your design intent and will produce the desired manufactured PCB.
Gerber File Viewing and Analysis
Use Gerber viewing software to inspect your generated files:
- Layer Alignment: Verify that all layers align correctly
- Aperture Usage: Check that apertures are properly defined and used
- Trace Continuity: Ensure traces are continuous without breaks
- Pad Registration: Verify pad alignment between layers
Common Issues and Troubleshooting
Several common issues can occur during Gerber generation. Understanding these problems and their solutions helps ensure successful file creation:
Aperture-Related Issues
| Issue | Cause | Solution |
|---|---|---|
| Missing Apertures | Undefined pad or trace sizes | Regenerate with proper aperture list |
| Aperture Overlap | Multiple similar sizes | Consolidate apertures within tolerance |
| Custom Shape Errors | Complex pad geometries | Simplify or use standard shapes |
Layer Registration Problems
Layer registration issues can cause serious manufacturing problems:
- Offset Layers: Check origin settings and coordinate systems
- Scaling Issues: Verify units are consistent across all files
- Rotation Problems: Ensure layer orientation is correct
Manufacturing File Package Organization
Organize your Gerber files in a logical, manufacturer-friendly structure:
PCB_Project_vX.X/
├── Gerber/
│ ├── Copper/
│ │ ├── Top_Copper.GTL
│ │ ├── Bottom_Copper.GBL
│ │ └── Internal_Layers.G*
│ ├── Mask/
│ │ ├── Top_Solder_Mask.GTS
│ │ ├── Bottom_Solder_Mask.GBS
│ │ ├── Top_Paste_Mask.GTP
│ │ └── Bottom_Paste_Mask.GBP
│ └── Drill/
│ ├── Plated_Holes.TXT
│ └── Non_Plated_Holes.TXT
├── Assembly/
│ ├── Pick_Place_Top.csv
│ ├── Pick_Place_Bottom.csv
│ └── Assembly_Drawings.pdf
└── Documentation/
├── Fabrication_Notes.pdf
├── Layer_Stack_Up.pdf
└── Drill_Chart.pdfWorking with Different Manufacturers
Different PCB manufacturers may have specific requirements for Gerber files. Understanding these variations helps ensure smooth manufacturing processes.
Manufacturer-Specific Requirements
Research your chosen manufacturer's requirements before generating files:
File Format Preferences
| Manufacturer Type | Preferred Format | Special Requirements |
|---|---|---|
| Prototype Houses | RS-274X Standard | Quick-turn compatibility |
| High-Volume Production | RS-274X with IPC standards | Detailed documentation |
| HDI Specialists | Advanced Gerber with via specifications | Detailed via documentation |
Communication with Manufacturing Partners
Effective communication with your manufacturer includes:
- Pre-Production Reviews: Discuss design intent and critical requirements
- DFM (Design for Manufacturing) Feedback: Incorporate manufacturer suggestions
- File Verification: Confirm files meet manufacturing capabilities
- Documentation Clarity: Provide clear fabrication notes and specifications
Automation and Batch Processing
For high-volume or repetitive projects, automating the Gerber export process can save significant time and reduce errors.
Output Job Files
Altium Designer's Output Job files (.OutJob) automate the generation of manufacturing deliverables:
- Create an Output Job file for your project
- Configure all required outputs (Gerber, drill, assembly files)
- Set up automatic file naming and organization
- Save the configuration for future use
Scripting and Customization
Advanced users can create custom scripts to automate specific aspects of the Gerber export process:
- Automated DRC checking before export
- Custom file naming conventions
- Batch processing of multiple designs
- Integration with version control systems
Documentation and Deliverables
A complete manufacturing package extends beyond just Gerber files. Professional PCB designs include comprehensive documentation to ensure successful manufacturing and assembly.
Essential Documentation Components
| Document Type | Content | Purpose |
|---|---|---|
| Fabrication Drawings | Board outline, dimensions, drill chart | Manufacturing reference |
| Assembly Drawings | Component placement, orientations | Assembly guidance |
| Bill of Materials | Component specifications, quantities | Procurement and assembly |
| Test Specifications | Test points, procedures | Quality assurance |
File Delivery Methods
Modern PCB projects require efficient file delivery methods:
- Compressed Archives: Standard ZIP files for email delivery
- Cloud Storage: Shared folders for large projects
- Manufacturing Portals: Direct upload to manufacturer systems
- Version Control: Git repositories for design history
Best Practices and Industry Standards
Following industry best practices ensures that your Gerber files meet professional standards and manufacturing requirements.
IPC Standards Compliance
Adhere to relevant IPC standards for PCB design and manufacturing:
- IPC-2221: Generic Standard on Printed Board Design
- IPC-2222: Sectional Design Standard for Rigid PCBs
- IPC-6012: Qualification and Performance Specification for Rigid PCBs
File Naming Conventions
Consistent file naming prevents confusion and errors:
| File Type | Naming Convention | Example |
|---|---|---|
| Top Copper | ProjectName_Top.GTL | MyProject_v1.2_Top.GTL |
| Bottom Copper | ProjectName_Bottom.GBL | MyProject_v1.2_Bottom.GBL |
| Drill Files | ProjectName_Drill.TXT | MyProject_v1.2_Drill.TXT |
Version Control and Revision Management
Implement proper version control for your Gerber files:
- Semantic Versioning: Use meaningful version numbers
- Change Documentation: Maintain revision logs
- Archive Management: Preserve historical versions
- Release Notes: Document changes between versions
Troubleshooting Common Export Issues
Even experienced designers encounter issues during Gerber export. Understanding common problems and their solutions helps maintain project schedules and quality.
File Size and Complexity Issues
Large or complex designs can cause export problems:
Optimization Strategies
- Aperture Consolidation: Reduce the number of unique apertures
- Layer Simplification: Combine similar layers where possible
- Region Management: Optimize polygon pour strategies
- Via Optimization: Use standard via sizes consistently
Compatibility Issues
Different software versions or settings can cause compatibility problems:
| Issue Type | Symptoms | Resolution |
|---|---|---|
| Version Conflicts | Import errors in CAM software | Use standard RS-274X format |
| Unit Mismatches | Scaling problems | Verify unit consistency |
| Coordinate Issues | Alignment problems | Check origin settings |
Manufacturing Feedback Integration
When manufacturers report issues with your Gerber files:
- Analyze Feedback: Understand the specific problem
- Design Review: Check if design changes are needed
- Export Reconfiguration: Adjust export settings as required
- Verification: Re-verify files before resubmission
Advanced Topics and Future Considerations
The PCB manufacturing industry continues to evolve, with new technologies and standards affecting Gerber file requirements.
Emerging Technologies
Stay informed about developing technologies that may affect your Gerber export process:
Advanced Manufacturing Techniques
- Additive Manufacturing: 3D printed electronics integration
- Embedded Components: Components within PCB layers
- Flexible-Rigid Combinations: Mixed substrate technologies
- Advanced Materials: New dielectric and conductor materials
Industry 4.0 Integration
Modern manufacturing increasingly relies on digital integration:
- Digital Twin Technology: Virtual manufacturing simulation
- IoT Integration: Connected manufacturing processes
- AI-Assisted Optimization: Automated design optimization
- Real-Time Quality Monitoring: Continuous process improvement
Frequently Asked Questions (FAQ)
What is the difference between RS-274D and RS-274X Gerber formats?
RS-274X (Extended Gerber) is the modern standard that includes aperture definitions within the file itself, making it self-contained and more reliable. RS-274D is the legacy format that required separate aperture files, leading to potential compatibility issues. Always use RS-274X for new designs as it provides better reliability and is universally supported by modern manufacturing equipment.
How do I ensure my Gerber files are compatible with my PCB manufacturer?
Before generating Gerber files, contact your manufacturer to obtain their specific requirements document. This typically includes preferred file formats, naming conventions, precision settings, and any special requirements for their equipment. Many manufacturers provide Altium Designer configuration files or detailed setup guides. Always request a pre-production review where the manufacturer verifies your files before starting production.
What should I do if my Gerber files are too large for email transmission?
Large Gerber files can be handled through several methods: compress files into ZIP archives to reduce size, use cloud storage services like Google Drive or Dropbox for sharing, upload directly to manufacturer portals if available, or use file transfer services for very large files. Most manufacturers accept files up to 25MB via email, but complex designs may exceed this limit and require alternative delivery methods.
Why do my drill files show incorrect hole sizes when viewed in CAM software?
This issue typically occurs due to unit mismatches or precision settings. Ensure your drill file units match your Gerber file units (preferably millimeters), verify that precision settings are appropriate for your hole sizes (3.3 format is standard), and check that your CAM viewing software is configured for the same units and precision as your exported files. Also confirm that via sizes in your design are within your manufacturer's capabilities.
How can I verify that my exported Gerber files accurately represent my PCB design?
Use a professional Gerber viewer to inspect your files layer by layer, checking for proper layer alignment, complete trace connectivity, correct pad sizes and locations, and proper aperture usage. Compare critical dimensions between your original design and the viewed Gerber files. Many manufacturers offer free DFM (Design for Manufacturability) checks that can identify potential issues before production. Additionally, generate a composite view of all layers to verify the complete PCB structure matches your design intent.
Conclusion
Mastering the export of Gerber files from Altium Designer is essential for successful PCB manufacturing. This comprehensive process involves careful preparation, precise configuration, thorough verification, and effective communication with manufacturing partners. By following the detailed procedures outlined in this guide, you can ensure that your PCB designs are accurately translated into manufacturable files that meet industry standards and manufacturer requirements.
The key to success lies in understanding not just the technical aspects of file generation, but also the manufacturing processes that will use these files. Regular communication with your manufacturing partners, adherence to industry standards, and continuous learning about evolving technologies will help you maintain the highest standards in PCB design and manufacturing.
Remember that Gerber export is not merely a technical process, but a critical bridge between your design vision and the physical realization of your PCB. Taking the time to properly configure, verify, and document your Gerber files will save time, reduce costs, and ensure the successful manufacture of your PCB designs.
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