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How to Generate AD Files Into Gerber

Generating accurate Gerber files from Altium Designer (AD) is a crucial step in the PCB manufacturing process. This comprehensive guide will walk you through the process, best practices, and common pitfalls to avoid when generating Gerber files from your Altium Designer projects.

Understanding Gerber Files

Gerber File Types

File ExtensionLayer TypeDescription
.GTLTop LayerTop copper layer
.GBLBottom LayerBottom copper layer
.GTOTop OverlayTop silkscreen
.GBOBottom OverlayBottom silkscreen
.GTSTop Solder MaskTop solder mask
.GBSBottom Solder MaskBottom solder mask
.GTPTop PasteTop solder paste
.GBPBottom PasteBottom solder paste
.GKOKeep-OutBoard outline
.GML/.GM1Mechanical 1Dimensions, assembly

Gerber Format Standards

FormatDescriptionUsage
RS-274XExtended GerberModern standard
RS-274DStandard GerberLegacy format
X2Latest formatAdvanced features

Pre-Generation Checklist

Generate the Gerber Files

Design Verification

Check ItemDescriptionCritical Level
DRCDesign Rule CheckCritical
ERCElectrical Rule CheckHigh
Copper BalanceLayer copper distributionMedium
Component ClearanceSpacing verificationHigh
Board OutlineEdge clearancesCritical

Layer Stack Management

Standard Layer Stack

Layer NameTypeInclude in Gerber
Top OverlaySilk ScreenYes
Top PastePaste MaskYes
Top SolderSolder MaskYes
Top LayerCopperYes
Inner Layer 1CopperYes
Inner Layer 2CopperYes
Bottom LayerCopperYes
Bottom SolderSolder MaskYes
Bottom PastePaste MaskYes
Bottom OverlaySilk ScreenYes
Mechanical 1MechanicalYes
Drill DrawingDrillYes

Gerber Generation Process

Output Configuration

General Settings

SettingRecommended ValuePurpose
UnitsmmStandard metric
Format4:04Precision level
Zero SuppressionLeadingIndustry standard
Reference PointRelativePosition accuracy

Layer Setup

Export Options

OptionSettingReason
Polygon Fill ModeSolidBetter manufacturing
Drill PairsLayer PairsClear drill definition
Drill DrawingSeparate FileManufacturing requirement
MirrorAs RequiredLayer-specific

NC Drill Configuration

Drill Checks
Drill Checks

Drill File Settings

ParameterValueDescription
FormatExcellon 2Industry standard
UnitsMetricStandard measurement
ZerosKeep zerosAccuracy maintenance
Tool AssignmentOptimizeEfficient drilling

Drill Table Configuration

FieldIncludeFormat
Tool NumberYesInteger
Hole SizeYesMetric
Plated StatusYesBoolean
Hole CountYesInteger
Tool DescriptionOptionalText

Output Generation

File Naming Convention

File TypeNaming FormatExample
Top LayerProjectName_GTLPCB_GTL
Bottom LayerProjectName_GBLPCB_GBL
Drill FileProjectName_DRLPCB_DRL
AssemblyProjectName_AssemblyPCB_Assembly

Output Job Configuration

Job File Structure

SectionContentPurpose
DocumentationAssembly drawingsAssembly guide
FabricationGerber filesManufacturing
NC DrillDrill filesHole creation
ReportQuality recordsDocumentation

Verification Steps

Post-Generation Checks

Check TypeToolPurpose
Gerber ViewCAM EditorVisual verification
Layer StackLayer Stack ManagerStack-up verification
Drill DataNC Drill EditorHole verification
DFMDFM CheckerManufacturability check

Common Issues Table

IssueCauseSolution
Missing LayersIncorrect setupReview layer setup
Misaligned DataReference point errorCheck origin setting
Incomplete OutlineLayer assignmentVerify board layer
Drill MismatchFormat errorCheck drill settings

Manufacturing Package

Required Files

File CategoryContentsFormat
Gerber SetAll layers.gbr
Drill FilesThrough-holes.drl
Assembly DrawingComponent placement.pdf
BOMComponent list.xlsx
READMESpecial instructions.txt

Zip File Structure

FolderContentsPurpose
GerberLayer filesManufacturing
DrillDrill dataHole creation
AssemblyDrawings, BOMAssembly guide
DocumentationInstructionsReference

Frequently Asked Questions

Q1: What are the essential Gerber files needed for PCB manufacturing?

A: The essential Gerber files include:

  • Top and bottom copper layers (.GTL, .GBL)
  • Solder mask layers (.GTS, .GBS)
  • Silkscreen layers (.GTO, .GBO)
  • Board outline (.GKO)
  • NC drill file (.DRL)
  • Solder paste layers if required (.GTP, .GBP) Always verify manufacturer-specific requirements as they may vary.

Q2: How do I verify my Gerber files are correct?

A: Follow these verification steps:

  • Use Altium’s Built-in Gerber viewer
  • Check all layers are present
  • Verify drill file alignment
  • Confirm board dimensions
  • Review layer polarity
  • Check component clearances Consider using third-party Gerber viewers for additional verification.

Q3: What are common Gerber generation mistakes to avoid?

A: Common mistakes include:

  • Wrong unit selection (mil vs. mm)
  • Incorrect layer assignment
  • Missing drill files
  • Improper board outline definition
  • Wrong polarity on negative layers
  • Forgetting to include all required layers Regular verification prevents most common errors.

Q4: How should I organize Gerber files for manufacturers?

A: Organize files as follows:

  • Use clear, consistent naming conventions
  • Group files by type in separate folders
  • Include a README file with special instructions
  • Compress all files into a single ZIP
  • Maintain proper file hierarchy
  • Include all necessary documentation Good organization reduces manufacturing delays.

Q5: What Gerber format should I use in Altium Designer?

A: Use these recommended settings:

  • Format: RS-274X (Extended Gerber)
  • Units: Millimeters
  • Resolution: 4:4
  • Zero Suppression: Leading
  • Coordinate Format: Absolute These settings ensure maximum compatibility with manufacturers.

Conclusion

Generating Gerber files from Altium Designer requires attention to detail and a systematic approach. Success depends on proper setup, careful verification, and following industry standards. By following the guidelines in this document and maintaining good documentation practices, you can ensure your Gerber files are accurate and ready for manufacturing.