How to Convert DXF to Gerber Files: A Complete Guide for PCB Engineers

Complete DXF to Gerber conversion guide for PCB engineers. Step-by-step process, free and paid software options, troubleshooting tips, and best practices.

If you’ve ever tried converting a DXF file to Gerber and ended up with something that looks nothing like your original design, you’re not alone. I’ve spent countless hours troubleshooting conversions that went sideways, and I’ve learned that the “simple” task of DXF to Gerber conversion is anything but straightforward.

This guide walks you through everything you need to know about converting DXF files to Gerber format, including the tools that actually work, the mistakes that trip up most designers, and the best practices that will save you from manufacturing headaches.

Understanding DXF and Gerber File Formats

Before diving into conversion methods, let’s establish what we’re actually working with. These two formats serve fundamentally different purposes, and understanding their differences explains why conversion can be tricky.

What is a DXF File?

DXF (Drawing Exchange Format) was developed by Autodesk in the early 1980s as a universal format for transferring CAD drawings between different software packages. It’s essentially a tagged data representation containing all the geometric information from an AutoCAD drawing, including lines, arcs, circles, text, and more complex entities like splines and hatches.

The format sees heavy use in mechanical engineering, architecture, and RF/microwave circuit design where designers prefer AutoCAD’s powerful drafting capabilities over traditional EDA tools. About 10-15% of PCB and RF layouts are still designed using mechanical CAD software like AutoCAD, SolidWorks, or ProE.

What is a Gerber File?

Gerber is the industry-standard format for PCB manufacturing, developed over 35 years ago. Unlike DXF’s complex entity types, Gerber is remarkably simple: it’s an ASCII text file containing X,Y coordinates and shapes (apertures/dcodes). Each Gerber file represents a single layer of your PCB design, whether that’s copper, solder mask, silkscreen, or the board outline.

Modern PCB fabricators require Gerber files because they provide unambiguous manufacturing instructions. There’s no interpretation needed; the file describes exactly what the photoplotter should image.

Key Differences Between DXF and Gerber Formats

Feature	DXF Format	Gerber Format
Primary Use	General CAD design, mechanical engineering	PCB manufacturing only
Data Structure	Hundreds of entity types (hatches, splines, 3D objects)	Simple X,Y coordinates with aperture definitions
Layer Handling	Flexible, user-defined layers	Strict layer types (copper, mask, silk)
Manufacturing Ready	No	Yes
File Complexity	High (supports 3D, text styles, blocks)	Low (2D only, minimal formatting)
Industry Adoption	Architecture, mechanical, electronics design	PCB fabrication worldwide

Why Convert DXF to Gerber Files?

PCB manufacturers won’t accept DXF files for production, and here’s why that makes sense from a manufacturing standpoint.

Manufacturing Requirements

When you send files to a fab house, they need precise, unambiguous data. DXF files require interpretation because the same visual result can be achieved using different entity types. A filled rectangle might be created with a hatch pattern, a closed polyline, or a region entity. Each requires different handling during conversion.

Gerber files eliminate this ambiguity. What you see is exactly what gets manufactured. There’s no guessing about fill patterns, line weights, or entity interpretations.

Design Verification and DFM Analysis

CAM tools can only perform Design for Manufacturing (DFM) checks on Gerber data. If you want to verify trace widths, check clearances, or analyze copper pour distribution, you need Gerber files. Running DFM checks before conversion means you’re validating something that doesn’t represent what will actually be manufactured.

Faster Production and Fewer Errors

Fab houses that accept DXF files typically charge extra for the interpretation time and increase lead times. Converting to Gerber yourself means faster quotes, quicker turnaround, and eliminates the risk of misinterpretation by someone who doesn’t understand your design intent.

Preparing Your DXF Files for Successful Conversion

Here’s where most conversion problems actually start. The way you create your DXF file determines whether conversion will be smooth or disastrous.

The Five Fundamental DXF Entities for Gerber Conversion

After years of conversion headaches, the industry has settled on five DXF entity types that convert reliably to Gerber data:

1. Polylines (or LW Polylines) These are the workhorses of DXF to Gerber conversion, used in approximately 80% of layouts. Polylines consist of connected lines and arcs with variable widths, making them perfect for traces, filled areas, and pad construction.

2. Circles Use circles for round pads, vias, and circular features. These translate directly to circular apertures in Gerber format.

3. Text Stick fonts (AutoCAD SHX fonts) convert best because they output as trace segments. Avoid TrueType fonts, which create complex filled shapes that may not convert correctly.

4. Blocks Blocks allow you to create reusable components like standard pad shapes or via structures. They convert cleanly when their internal entities follow the other four fundamental types.

5. Inserts Inserts are instances of blocks placed in your drawing. Use them for repetitive elements like connector footprints.

DXF Entities to Avoid

Entity Type	Why It Causes Problems
Hatches	Complex fill algorithms don’t translate to Gerber’s simple fills
Splines	Gerber only supports lines and arcs, requiring approximation
3D Objects	Gerber is strictly 2D
TrueType Fonts	Create complex filled shapes instead of trace segments
Regions	Require complex boolean operations to convert
Tapered Polylines	Width variations may not transfer correctly

Setting Up Your DXF for Clean Conversion

Before exporting your DXF file, verify these critical settings:

Origin Placement: Keep your design close to the origin. A design starting at X=1750mm will cause problems during conversion.

Units Consistency: Ensure your drawing units match what you’ll specify during import. Mixing metric and imperial units is a common source of scaling errors.

Layer Organization: Separate your design elements onto distinct layers that correspond to PCB layers. A top copper layer should only contain top copper elements.

Clean Geometry: Remove construction lines, reference geometry, and any entities not intended for manufacturing.

DXF to Gerber Conversion Software Options

The right tool depends on your budget, complexity of designs, and how often you need to perform conversions.

Professional Software Solutions

Software	Key Features	Best For	Pricing
FAB 3000	Intelligent import, DFM checks, automated layer mapping	Professional PCB/RF engineers	Commercial
ACE 3000	Specialized translator, 2D/3D support	Complex conversions, MEMS designs	Commercial
ViewMate Pro	DXF import/export, Gerber editing, layer comparison	CAM editing and conversion	Commercial
GerbView	Multi-format support, PDF creation, batch conversion	Viewing and converting multiple formats	Commercial
Altium Designer	Full EDA suite with DXF import	Integrated PCB design workflow	Commercial

Free and Open Source Options

KiCad While not primarily a converter, KiCad can import DXF files and export Gerbers. Import your DXF to the Edge.Cuts or other appropriate layer, then use File → Plot to generate Gerber output.

FlatCAM This open-source tool specializes in PCB prototyping workflows. It can import various formats and generate manufacturing data, though it’s better suited for Gerber to DXF conversion.

dxf2gbr A free command-line converter available on SourceForge. It handles basic DXF to Gerber conversion but has limited entity support.

Online Converters

Online tools exist for quick, one-off conversions, but they come with significant limitations:

• Limited control over conversion parameters
• File size restrictions
• Potential confidentiality concerns for proprietary designs
• Less reliable results for complex geometries

For production work, desktop software remains the safer choice.

Step-by-Step DXF to Gerber Conversion Process

Here’s the workflow I follow for reliable conversions:

Step 1: Prepare Your Source File

Open your DXF in AutoCAD or your preferred CAD software and verify:

• All geometry uses supported entity types
• Layers are properly organized
• Units are correctly set
• Design is positioned near the origin

Step 2: Import into Conversion Software

Using FAB 3000 as an example:

1. Launch the software and create a new project
2. Select File → Import → DXF/DWG
3. Set import units to match your source file
4. Choose layer mapping options

Step 3: Verify Import Accuracy

This step catches most conversion problems before they become manufacturing issues:

• Use measurement tools to verify critical dimensions
• Check that all elements imported correctly
• Verify layer assignments match your intent
• Look for any missing or distorted geometry

Step 4: Configure Layer Mapping

Assign each imported layer to the appropriate Gerber layer type:

DXF Layer	Gerber Assignment
TOP_COPPER	Top Copper (GTL)
BOT_COPPER	Bottom Copper (GBL)
TOP_MASK	Top Solder Mask (GTS)
BOT_MASK	Bottom Solder Mask (GBS)
SILKSCREEN	Top Silk (GTO)
OUTLINE	Board Outline (GKO)

Step 5: Generate Gerber Output

Configure export settings:

• Format: RS-274X (Extended Gerber)
• Precision: 2:5 or 2:6 for inches
• Units: Match your design units
• Zero suppression: Consistent across all files

Step 6: Validate Output Files

Load the generated Gerbers into a viewer and verify:

• All layers are present
• Geometry matches the original design
• No artifacts or conversion errors exist
• Board outline is correct

Troubleshooting Common DXF to Gerber Conversion Issues

Problem: Converted Design Has Wrong Scale

Cause: Unit mismatch between source and destination Solution: Verify units in both your CAD software and conversion tool. Use reference measurements to confirm scale accuracy.

Problem: Filled Areas Appear as Outlines Only

Cause: Closed polylines without fill settings, or hatches that don’t convert Solution: Create filled areas using closed zero-width polylines with properly defined fill boundaries. Avoid hatches.

Problem: Text Appears Garbled or Missing

Cause: TrueType fonts or unsupported text styles Solution: Convert text to SHX (stick) fonts before export, or explode text to polylines if necessary.

Problem: Drill Holes Not Appearing

Cause: Circles not on a designated drill layer, or drill file not generated separately Solution: Ensure circles intended as drill hits are on a dedicated layer. Generate Excellon drill files separately from Gerber files.

Problem: Complex Geometry Missing

Cause: Unsupported entity types filtered out during import Solution: Simplify geometry to the five fundamental entities before export.

Useful Resources and Tools

Software Downloads

• FAB 3000 Demo: https://www.numericalinnovations.com (30-day trial)
• KiCad: https://kicad.org (Free, open source)
• GerbView: https://www.gerbview.com (30-day evaluation)
• FlatCAM: https://flatcam.org (Free, open source)
• dxf2gbr: https://sourceforge.net/projects/dxf2gbr (Free)

Documentation and Guides

• Gerber Format Specification: https://www.ucamco.com/en/gerber
• DXF Reference Guide: Autodesk Developer Documentation
• Bay Area Circuits Conversion Guide: https://bayareacircuits.com/dxf-to-gerber-conversion-guide/
• Numerical Innovations Tutorials: https://www.numericalinnovations.com/dxf-conversions

Gerber Viewers for Validation

Viewer	Platform	Cost
KiCad GerbView	Windows, Mac, Linux	Free
ViewMate	Windows	Free (basic)
ZofzPCB	Windows	Free
Online Gerber Viewer	Web	Free

Best Practices for DXF to Gerber Conversion

After handling hundreds of conversions, these practices consistently produce good results:

1. Simplify Before Converting Remove anything that isn’t essential for manufacturing. Construction geometry, reference dimensions, and notes should be on non-exported layers or deleted entirely.

2. Validate at Every Step Check your source file, verify the import, and validate the output. Finding problems early saves manufacturing delays later.

3. Maintain Unit Consistency Decide on metric or imperial units at the start and stick with them throughout the process.

4. Document Your Layer Mapping Keep a record of which DXF layers map to which Gerber files. This makes revisions easier and reduces errors on future projects.

5. Archive Both Formats Save your original DXF alongside the generated Gerbers. If you need to make changes, working from the source file is always better than editing Gerbers.

Frequently Asked Questions About DXF to Gerber Conversion

Can I Convert DXF Files to Gerber Online for Free?

Yes, several online tools offer free DXF to Gerber conversion, but they typically have limitations on file size, complexity, and conversion options. For professional work or complex designs, desktop software provides better control and more reliable results. Online converters work best for simple, one-off conversions where precision isn’t critical.

What is the Best Free DXF to Gerber Converter?

KiCad offers the most capable free solution for DXF to Gerber conversion. While it’s primarily a PCB design suite, you can import DXF files to specific layers and generate Gerbers using the Plot function. FlatCAM and dxf2gbr are alternatives, though they have more limited entity support.

Why Does My PCB Manufacturer Require Gerber Files Instead of DXF?

PCB manufacturers require Gerber files because they provide unambiguous manufacturing instructions. DXF files can represent the same geometry using many different entity types, each requiring interpretation. Gerbers eliminate this ambiguity, which means faster production, fewer errors, and consistent results across different manufacturers.

How Do I Handle Board Outlines in DXF to Gerber Conversion?

Board outlines should be created using a single, continuous closed polyline with zero width. Place this on a dedicated layer that maps to the Gerber mechanical layer or board outline. Avoid using multiple line segments or arcs, as gaps between segments can cause manufacturing issues.

Can I Convert Multiple DXF Layers to Separate Gerber Files in One Operation?

Most professional conversion tools support batch conversion of multiple layers. Configure your layer mapping to assign each DXF layer to the appropriate Gerber layer type, then export all layers simultaneously. This ensures consistent settings across all output files and maintains layer registration.

Working with Different CAD Software for DXF Export

Different CAD packages have their own quirks when exporting DXF files. Here’s what to watch for with common tools:

AutoCAD and AutoCAD LT

AutoCAD produces the most compatible DXF files since it created the format. Before exporting:

• Run AUDIT to check for drawing errors
• Use PURGE to remove unused elements
• Set LTSCALE appropriately for line types
• Export from Model Space, not Paper Space

SolidWorks

When exporting from SolidWorks, select the appropriate sketch or face to export. The DXF export options allow you to choose between 2D and 3D output. For PCB work, always select 2D and verify that spline geometry converts to polylines.

Fusion 360

Fusion 360’s DXF export requires sketches to be projected to a plane. Complex 3D geometry must be converted to 2D sketches before export. Use the Export sketch function rather than full assembly export.

Conclusion

Converting DXF files to Gerber format doesn’t have to be complicated, but it does require understanding what each format expects. By sticking to the five fundamental entity types, using proper layer organization, and validating your results at each step, you can achieve clean conversions consistently.

The key takeaway is this: preparation matters more than the conversion tool you choose. A well-organized DXF file will convert cleanly in almost any software, while a complex file filled with hatches, splines, and 3D objects will cause problems regardless of how sophisticated your converter is.

Take the time to set up your source files correctly, and the conversion process becomes almost trivial. Skip the preparation, and you’ll spend far more time troubleshooting than you would have spent doing it right from the start.