Gerber Files: PCB Design to PCB Fabrication with Your Manufacturer

Introduction: Everything About Gerber Files in PCB Manufacturing

In the field of electronic design, Gerber files serve as the core component of the printed circuit board (PCB) industry, governing the entire workflow from design to production. All PCB designers, whether novices or seasoned engineers, must acquire a thorough understanding of Gerber file knowledge, as this directly determines the smooth execution of the circuit board manufacturing process and the achievement of flawless production.

When designing a printed circuit board, all design data—from schematic drawing to layout routing—is ultimately compiled into a set of standardized files that can be precisely read by manufacturing equipment. These files convey the complete physical manufacturing specifications of the circuit board to the manufacturer and are universally referred to as Gerber files for PCB production. PCB manufacturers worldwide rely on such standardized files as the production blueprint to accurately translate design plans into physical circuit boards with proper electrical functionality.

You’ll learn in this guide:

• Why Gerber files are essential for the manufacture of the PCB
• The meaning and structure of the Gerber file format
• How to generate and check files from every major PCB design software
• The critical role of Gerber files in PCB assembly, drilling, production and quality assurance
• Best practices for working with Gerber file extensions, fonts, viewers and file format compatibility

Gerber Files: The Foundation for PCB Fabrication and Manufacturing

Unlike schematic files or simulation data, Gerber files are the file format used by PCB manufacturers to describe every layer of the PCB in detail. PCB Gerber files act as digital blueprints. They are used to describe:

• Copper layers
• Solder mask layers
• Silkscreen text and symbols
• NC drill locations, cutouts, slots and vias
• Board outlines and mechanical features
• Paste masks for solder stencils

Manufacturers require files for PCB production in the Gerber file format, as each file contains straightforward instructions for fabrication machinery.

Why Gerber Files Are Used:

• They ensure compatibility between PCB designers and manufacturing companies—regardless of software platform.
• All types of PCB manufacturers, including vendors specializing in prototype fabrication and factories engaged in mass production, accept Gerber files as the standard format.
• Gerber files are applicable to all manufacturing stages, from basic single-layer boards to high-density interconnect boards. As the core medium that transforms design data into physical products, they serve a critical and irreplaceable role.

What is a Gerber File? Format, Role and History

A Gerber file is an ASCII text file designed specifically to convey all graphical and functional details of a circuit board. It defines exactly what is manufactured on every layer. Originally created by Joseph Gerber, Gerber files in PCB manufacturing have become the standard thanks to their universal readability and detail.

File Format Used by PCB Fabricators

Gerber files were originally designed as NC (Numerical Control) data sets to drive photoplotters—early machines that created photographic films for copper traces. Modern files for PCB are still text-based, but now include a wider variety of commands, metadata and formatting for today’s sophisticated automated production.

Key Elements in a Gerber File:

• All information needed for each individual layer of the PCB
• Numerical parameters (apertures, coordinates)
• Drawing commands (to trace paths, flash pads or drill holes)
• Configuration and layer-specific data

Gerber File Structure & Key Elements of the PCB

Proficiency in interpreting Gerber files is an essential core competency for every PCB designer. These ASCII text files utilize a structured format designed to address the dual needs of direct human review and efficient machine parsing.

A typical Gerber file contains:

1. Header/Configuration:File format version, units (mm or inches), coordinate settings.
2. Aperture Definitions:The shapes and sizes used to draw copper, silkscreen and mask features.
3. XY Coordinates:Numerical data specifying where each feature is placed on the PCB layout.
4. Draw and Flash Commands:Tells manufacturing tools to draw traces, create pads or perform other actions.
5. End-of-File Marker:Signals completion—ensures different Gerber viewers and machines interpret the file correctly.

Data in Gerber Files: Layer of the PCB Explained

A complete set of PCB Gerber files comprises separate files for each constituent element of the printed circuit board. The typically included layers and their functions are as follows:

Why separate Gerber files?

Each constituent element of a printed circuit board requires specific manufacturing process steps: copper layers undergo etching, solder layers involve printing or mask application, while vias and holes rely on mechanical drilling. This requirement for distinct manufacturing processes dictates that design software must generate separate files for each element. Consequently, all PCB design software outputs multiple files before sending designs to production.

Gerber File Formats and Extensions: RS-274 & Gerber X2/X3

The evolution of the Gerber file format closely parallels the technological advancement of the PCB manufacturing industry. Designers must master the characteristics and compatibility requirements of different Gerber formats. This knowledge ensures the smooth acceptance of design files by manufacturers and helps avoid disruptions in the production process due to format issues.

The Major Gerber File Formats

RS-274-D (Standard Gerber)

• The oldest file format used by PCB fabricators.
• Format:ASCII text file but lacks embedded aperture definitions (aperture: the “shape” of the tool that draws the PCB feature).
• Requires a separate aperture file; prone to errors due to manual synchronization.
• Use Today:Only legacy shops or very old workflows; almost never recommended in modern PCB fabrication.

RS-274-X (Extended Gerber)

• Adds embedded configuration parameters and aperture definitions right into the file.
• Became the global standard thanks to improved compatibility and fewer human errors.
• This is the default Gerber file format used by most of the PCB industry for the last two decades.
• Can easily be read by any Gerber viewer software.

Latest Gerber X2

• Builds on RS-274-X, adding intelligent PCB attributes (e.g., file contains explicit info about layer type, impedance-controlled traces, pads defined as plated or non-plated and netlist connections).
• Greatly improves automation, DFM checks and communication between PCB designer and PCB manufacturer.
• Modern PCB manufacturing companies and high-reliability industries prefer X2 for its clarity and traceability.

Gerber X3 (Emerging)

• Incorporates even more metadata, especially related to assembly, BOM and component info.
• Still being adopted, but will soon support a true digital twin for sophisticated, “intelligent PCB” production.

How to Create Gerber Files With PCB Design Software

No matter your preferred EDA tool, Gerber export is always the pivotal last step before you send a board for manufacturing. Here’s how the process works in leading PCB programs:

General Steps (Applicable to Any PCB Design Software)

1. Complete your PCB layout and ensure your schematic and board rules are validated.
2. Run a design rule check (DRC) – this checks that all spacings and trace widths meet fabrication specs.
3. Open the Gerber export or CAM output dialog in your software.
4. Choose which PCB layers to export—copper (all), solder mask, silkscreen, board outline and drill data.
5. Configure advanced settings: units (mm/inch), coordinate format, aperture format, decimal precision.
6. Generate the files and review output folder for a complete file set.

Creating Gerber Files in Altium Designer (Detailed Example)

• Use Files > Fabrication Outputs > Gerber Files
• Select required layers (top copper, bottom copper, inner layers, masks, silkscreen, outline).
• Configure format: RS-274-X or Gerber X2 preferred.
• Generate Drill Files as Excellon format for all holes and vias.
• Review each Gerber in Altium’s Gerber viewer before sending.

Creating Gerber Files in KiCad

• From PCB Editor, go to Plot
• Select each layer you wish to export as Gerber.
• Configure units, format, and output directory.
• Export drill file separately (.drl/.txt).
• Optionally, view exported files with built-in GerbView.

Creating Gerber Files in Autodesk Eagle

• Access CAM Processor.
• Select (or create) the appropriate CAM job for Gerber output.
• Assign outputs to .GTL, .GBL, .GTS, .GTO, etc.
• Generate NC drill file for PCB drilling.
• Preview with an external Gerber viewer to catch errors.

Tips for Creating Proper Gerber Files

• Always generate a separate Gerber file for each layer of the PCB.
• Double-check that every essential file is present before submitting.
• Include a README or layer info table for PCB manufacturing—especially useful if using custom file names/extensions.
• When new to PCB design, ask your PCB manufacturer for a sample set as a reference.

Viewing, Checking and Validating Gerber Files Before Sending

Before your Gerber files ever reach a PCB manufacturer, they should be rigorously checked. This step eliminates “surprise” mistakes that can ruin an entire PCB production run.

Best Practices: Check Files Before Sending

• Open your full Gerber file set in at least one dedicated Gerber viewer software (e.g., Gerbv, ViewMate, ZofzPCB or your EDA tool’s viewer).
• Verify each file contains exactly what you expect: copper traces, drill holes, text, mask and outline.
• Visually overlay all layers to confirm perfect alignment (misalignment is a top reason files are rejected in fabrication).
• Run built-in DRC/DFM checks in your viewer, if possible.
• Look for common errors: missing solder mask clearances, silkscreen text overlapping pads, board outline not closed or missing paste files for SMT assembly.

Different Gerber viewers sometimes reveal subtle issues missed by other tools. For full confidence, check your files in at least two viewers.

The Gerber File’s Role in PCB Manufacturing and Fabrication

Gerber files in PCB manufacturing are more than just maps—they are the step-by-step instructions used to describe exactly how to produce your circuit boards.

Fabrication Steps Driven by Gerber Files

1. Imaging:CAM software reads your Gerber copper and mask files, generating artwork for copper etching and solder mask application.
2. Drilling:Drill files specify locations and sizes for all vias and holes. CNC drills execute your exact plan—no guesswork.
3. Solder Mask and Silkscreen:Gerber mask and legend files tell printers/inkjets where to coat and where to print part numbers and text.
4. Board Outline & Routing:Mechanical outlines from Gerber files control PCB routers and v-cut machines, defining the final board shape.
5. Solder Paste Stencil:For SMT, separate Gerber file(s) define the exact pattern for laser-cutting solder paste stencils.

Every step, from chemical etching to the last assembly stage, is coordinated using the data in Gerber files. This robust, stepwise process is why Gerber files are used by PCB fabricators regardless of board complexity.

Manual Gerber File Editing, Optimization and File Compatibility

Sometimes, custom needs or factory feedback require direct changes to your Gerber outputs.

When to Edit or Optimize Gerber Files

• Merging/Panelizing multiple small boards into one array (for assembly efficiency).
• Fixing misplaced board outlines or mechanical drawings.
• Adding manufacturing marks, QR codes or logos not present in the original design.
• Streamlining files by removing redundant or excessive aperture definitions, reducing file size for transfer or upload.
• Preparing legacy files for compatibility with new fabrication equipment or intelligent PCB workflows.

Ensuring Compatibility

• Always save edited Gerber files in a format accepted by your PCB manufacturer.
• Whenever you edit, always check files in a separate Gerber viewer before sending.
• Include updated README documentation explaining changes—especially for advanced or non-standard edits.

Security, IP Protection and File Submission for PCB Production

Because Gerber files contain your full circuit board design, protecting IP is as vital as the technical details.

Security Best Practices

• Use password-protected or encrypted archives when sending files to your PCB manufacturer.
• Work only with reputable, NDA-bound fabrication partners for sensitive or proprietary designs.
• Watermark your silkscreen or include hidden copper pattern shapes for IP traceability—helpful for proof of authorship.
• For areas with high IP sensitivity, consider split fabrication strategies: produce inner layers at trusted sites and less sensitive ones at third-party fabs.

File Submission Checklist

Before sending files for PCB production, ensure the following steps are meticulously followed:

• All Gerber files for PCB boards are present:Copper layers, solder mask, silkscreen, drill files and board outline.
• All file names and extensionsmatch the format used by your PCB manufacturer (.GTL, .GBL, .DRL, etc.).
• txt or mapping table included: Match file names to layers and describe any special fabrication instructions.
• Files are zipped into a single, organized archive– makes transfer easy and tracks versions.
• Conduct a final review using different Gerber viewers:Viewing your files with another tool (besides your EDA’s built-in viewer) often catches hidden errors.
• Specify material, finish, stack-up requirementsin accompanying BOM or notes, especially for complex or high-frequency PCB fabrication.
• Ensure all data in Gerber files is complete:Double-check details like texts and fonts for Gerber silkscreen, clear drill layer definitions, unambiguous mechanical layer details and correct outline closure.
• Confirm netlist information to the PCB fabricator:If using intelligent file formats (like X2 or IPC-2581) include netlists for automated compliance checks.

Texts and Fonts for Gerber: Silkscreen Details and DFM

Silkscreen data in Gerber files—the labels, part designators and instructions—are critical for effective PCB assembly and maintenance. The importance of Gerber files here isn’t just readability: it’s manufacturability.

Tips for Effective Silkscreen and Text in Gerber:

• For text annotations in PCB design, it is recommended to use vector or standard linear fonts, while complex TrueType fonts should be avoided. This approach ensures that all design elements maintain clear graphic edges, precise geometric reproducibility and reliable mechanical recognition during the manufacturing process.
• Ensure silkscreen text is at least 1 mm tall and 0.15 mm (6 mils) line width; smaller text may blur or disappear in fabrication.
• Keep all text and symbols away from pads and copper layers to avoid solder mask or assembly errors.
• Use white, yellow or green inks as recommended by your PCB manufacturer for best contrast on your board design.
• Always check texts and fonts for Gerber output in several different Gerber viewer software tools to ensure no text is clipped or misaligned.

FAQs: Everything About Gerber Files in the PCB Industry

What is the importance of Gerber files in PCB fabrication?

Gerber files are essential because they provide the PCB manufacturer with precise, standardized instructions to fabricate every layer of the PCB. This ensures manufacturability, reduces guesswork and prevents costly mistakes in production and PCB assembly.

How are Gerber files generated in PCB design tools?

Every PCB design software (Altium Designer, KiCad, Eagle, EasyEDA) includes a Gerber export function. Users select the layers they wish to output, the desired file format, and coordinate precision, then review the results with integrated or separate Gerber viewer software.

What are Gerber file extensions and why are they important?

Gerber file extensions (.GTL, .GBL, .GTS, etc.) help the PCB industry quickly identify what layer or fabrication process the file contains. Correct extensions reduce errors, enhance compatibility between PCB designers and manufacturers and are used by PCB fabricators worldwide.

Can you edit or view Gerber files after export?

Absolutely. Before sending, PCB designers should always inspect and, if necessary, manually edit or optimize Gerber files using CAM software or Gerber viewers to catch mistakes undetected by the initial design tool.

Are there intelligent PCB file formats besides Gerber?

Yes! ODB++ and IPC-2581 are increasingly used for complex, high-speed, or high-reliability PCB production. These intelligent PCB formats combine Gerber-style geometry with netlist, stack-up, BOM and assembly information in a single package, streamlining data handoff and verification.

Gerber Alternatives: Intelligent PCB Manufacturing Formats

With the complexity of modern electronic design, intelligent PCB file formats are rising in popularity:

• ODB++: Includes geometry, netlist, BOM, testpoints and stack-ups—all in one. Many large PCB manufacturers are adopting ODB++ for its integration and error resistance.
• IPC-2581: An open, XML-based standard aiming to unite layout, netlist, stack-up and assembly instructions—leading the “digital twin” concept for smart manufacturing.
• Gerber X2/X3: An evolution of the original, adding intelligent metadata and file contains features for true automated DFM and DFA checks.

Despite these developments, the Gerber file format remains the most used by the PCB industry due to simplicity, legacy compatibility and universal acceptance by fabrication shops.

Importance of Gerber Files for PCB Board Design

Mastering Gerber files bridges the gap between innovative PCB design and flawless, high-yield PCB manufacturing.

Key Takeaways:

• Gerber files are essential for specifying every element and layer of the PCB.
• They are the format used by all PCB manufacturers to guarantee accurate fabrication.
• Proper files for PCB production include copper, solder mask, silkscreen, drilling and outline—each exported as a separate Gerber file.
• View, validate and check files before sending for seamless manufacturing, reduced delays and higher reliability.

About LHDPCB: Trusted PCB Manufacturer & Gerber File Experts

LHDPCB is a global leader in PCB manufacturing, assembly and prototyping. As a customer-focused PCB manufacturer, LHDPCB offers:

• Advanced multilayer, rigid, flex, and HDI PCB capabilities.
• Fast Gerber review, DFM feedback and problem-solving for new to PCB design professionals and large OEMs alike.
• Free Gerber file validation before fabrication and a dedicated engineering team to help you create, inspect and send proper Gerber files for any order.
• Online Gerber file upload and instant quote for everything from single prototypes to high-volume smart manufacturing.