How to Generate Gerber Files for PCB Manufacturing: Complete Guide

How to Generate Gerber Files for PCB Manufacturing: A Complete Guide

If you have ever designed a printed circuit board (PCB), you may know that you usually cannot send the original CAD design file directly to a PCB manufacturer and expect production to begin immediately. Manufacturers typically need a set of standardized manufacturing data, most commonly Gerber files, along with drill data and other fabrication information.

Gerber files translate your PCB design into manufacturing-ready 2D artwork. They tell the fabricator where copper should remain, where solder mask should be applied or cleared, where silkscreen markings should appear, and where holes need to be drilled.

For first-time PCB designers, learning how to generate Gerber files for PCB manufacturing may seem complicated. However, once you understand the basic principles, the process becomes straightforward. Gerber files essentially serve as the communication interface between your PCB design software and the physical circuit board.

This guide explains how to create Gerber files for a PCB, from finalizing the design and selecting fabrication layers to generating drill files, validating the output, and preparing the final manufacturing package.

What Are Gerber Files?

Gerber files are industry-standard 2D image files used to represent individual layers of a PCB design. Each file generally corresponds to one manufacturing layer or fabrication feature.

Instead of sending the entire PCB design as one editable CAD file, the design is separated into individual manufacturing outputs. A typical PCB project may include:

Top copper layer
Bottom copper layer
Internal copper layers for multilayer PCBs
Top solder mask
Bottom solder mask
Top silkscreen
Bottom silkscreen
Board outline
Drill data
Additional fabrication or assembly documentation when required

Modern Gerber files commonly use the RS-274X or newer Gerber X2 format. Gerber X2 can include additional metadata that helps manufacturers interpret layer functions, although manufacturers may still specify which format they prefer.

Drill data is generally supplied separately, often in Excellon format.

Therefore, a complete PCB manufacturing file package normally consists of more than just Gerber artwork.

Why Are Gerber Files Important?

You may wonder why PCB manufacturers cannot simply use the original CAD file supplied by the designer.

The main reason is software compatibility and manufacturing consistency.

PCB design programs such as KiCad, Altium Designer, and Autodesk Fusion Electronics may use their own native project formats. These files can contain much more information than a manufacturer needs for physical fabrication, including schematic relationships, component libraries, design rules, editing information, and other project-specific data.

A manufacturer does not necessarily need all of that information to fabricate the bare PCB. Instead, they need clearly defined manufacturing outputs.

This is where Gerber files become important.

A properly generated Gerber package provides manufacturers with standardized artwork for individual PCB layers. Regardless of which CAD platform was used to create the original design, the manufacturer can import the manufacturing data into CAM software for engineering review and production preparation.

In this sense, Gerber data acts as a bridge between PCB design and PCB manufacturing.

However, Gerber files are not the complete manufacturing specification by themselves. Important information such as board thickness, copper weight, surface finish, material, solder mask color, impedance requirements, tolerances, and special fabrication instructions may need to be provided separately.

How to Generate Gerber Files for a PCB

The exact menu names vary between PCB design programs, but the overall workflow is similar.

Step 1: Finalize Your PCB Design

Before generating manufacturing files, complete the schematic and PCB layout.

Do not export Gerber files simply because the routing appears finished. First perform a comprehensive design review and run the appropriate Design Rule Check (DRC).

Pay particular attention to:

PCB layout and component placement
Trace width and spacing
Copper-to-edge clearance
Pad and via dimensions
Hole sizes
Annular rings
Solder mask clearances
Silkscreen placement
Board outline
Electrical connectivity
Power and ground routing
Design-for-manufacturing (DFM) requirements

Also verify that the board outline is a closed and clearly defined geometry. An incorrect board outline can cause serious problems during fabrication.

If the manufacturer has published minimum trace widths, spacing, hole sizes, or other fabrication limits, check the design against those requirements before generating the files.

Step 2: Open the Gerber Export Tool

After the design has passed your checks, open the manufacturing output or Gerber export function in your PCB design software.

The exact location depends on the software version.

For example, common workflows include:

KiCad: Use the PCB Editor’s Gerber and drill file generation tools.
Altium Designer: Use the manufacturing output options to generate Gerber and drill files.
Autodesk Fusion Electronics: Use the CAM or manufacturing output workflow appropriate to the PCB design environment.

The export window normally allows you to select the layers and output parameters required for fabrication.

Step 3: Select the Required PCB Layers

The next step is to select the correct manufacturing layers.

For a simple two-layer PCB, the package commonly includes:

Top copper
Bottom copper
Top solder mask
Bottom solder mask
Top silkscreen
Bottom silkscreen
Board outline
Drill files

For a multilayer PCB, all internal copper layers must also be exported.

For example, a four-layer PCB may require:

Top copper
Inner Layer 1
Inner Layer 2
Bottom copper
Top solder mask
Bottom solder mask
Top silkscreen
Bottom silkscreen
Board outline
Drill data

It is important to understand the difference between electrical layers and documentation layers. Do not accidentally export unrelated mechanical, assembly, courtyard, or documentation layers as fabrication artwork unless the manufacturer specifically requests them.

Step 4: Use a Clear File Naming Convention

A consistent naming convention makes the manufacturing package easier to review.

Common Gerber extensions include:

File Extension	Typical Layer
`.GTL`	Top Copper
`.GBL`	Bottom Copper
`.G1`, `.G2`, etc.	Internal Copper Layers, depending on CAD output
`.GTS`	Top Solder Mask
`.GBS`	Bottom Solder Mask
`.GTO`	Top Silkscreen
`.GBO`	Bottom Silkscreen
`.GKO` or `.GM1`	Mechanical/Board Outline, depending on software
`.DRL`	Drill File
`.TXT`	Drill File in some CAD workflows

These extensions are widely used, but naming conventions are not completely universal. Always follow the requirements of your selected PCB manufacturer when they specify a particular naming scheme.

For multilayer boards, make sure internal layers are clearly identifiable and ordered correctly.

Step 5: Configure the Gerber Output Parameters

When learning how to generate Gerber files, output settings deserve special attention.

Several parameters should be reviewed before exporting.

Units

Gerber data can be generated using metric or imperial units.

Choose the unit system required by your manufacturing workflow. More importantly, ensure that all exported files are interpreted consistently.

Format and Resolution

Modern Gerber formats support high precision, so the output format should provide sufficient coordinate resolution for the smallest features in your design.

Older tutorials may recommend specific settings such as 2:5 or 4:6. These are examples of coordinate formats rather than universal requirements.

For most modern PCB manufacturing workflows, the recommended approach is to use the output settings supported by your PCB CAD software and accepted by your manufacturer.

Coordinate System

Absolute coordinates are commonly preferred because they provide an unambiguous reference for the artwork.

Avoid changing coordinate conventions between different files in the same manufacturing package.

Aperture and Gerber Format

If your software offers RS-274X or Gerber X2, use the format recommended by your PCB manufacturer.

Gerber X2 can provide layer-function information that may help CAM systems identify the purpose of individual files. However, compatibility requirements should always take priority.

Step 6: Generate the PCB Drill Files

Gerber artwork does not normally contain all the information required to manufacture PCB holes.

You also need to generate drill data.

Excellon drill files are widely used to communicate hole information to PCB manufacturers. Depending on the design, the drill output may define:

Hole diameter
Hole location
Plated or non-plated hole information
Drill tool sizes
Hole quantities
Drill coordinates

Make sure all required holes are included.

This is particularly important for:

Plated through-holes
Vias
Mounting holes
Connector holes
Mechanical holes
Non-plated through-holes

For advanced boards, additional information may be required for special hole structures or sequential fabrication processes.

Step 7: Export the Board Outline

The board outline is one of the most important pieces of PCB manufacturing data.

Make sure the finished board dimensions and shape are clearly defined.

For a rectangular PCB, this is relatively simple. However, boards with slots, cutouts, rounded corners, castellations, or irregular shapes require additional attention.

Check that:

The outline is closed.
There are no duplicate lines.
The outline is located on the correct layer.
Internal cutouts are clearly defined.
Slots are represented according to the manufacturer’s requirements.
Board dimensions match the intended design.

An incorrect outline can result in incorrect routing, machining, or panelization.

Step 8: Check the Gerber Files Using a Gerber Viewer

Never send newly generated manufacturing files directly to the manufacturer without reviewing them.

A Gerber viewer allows you to inspect the exported files independently of your original PCB CAD environment.

Load all Gerber and drill files into the viewer and check them layer by layer.

Pay attention to:

Copper traces
Pads
Vias
Drill locations
Board outline
Solder mask openings
Silkscreen markings
Layer alignment
Internal copper layers
Text orientation
Polarity and layer interpretation

You should also inspect the complete stack of layers together.

For example, confirm that drill holes align correctly with pads and that silkscreen reference designators do not unnecessarily overlap component pads.

Step 9: Compare the Gerber Output With the Original PCB Layout

A Gerber viewer check should not replace a final comparison with your original PCB design.

Compare the exported manufacturing files with the source PCB layout and confirm that:

No copper features are missing.
No unwanted copper appears.
All required layers are present.
Vias are located correctly.
Drill locations match the design.
The board outline is correct.
Solder mask openings are correct.
Silkscreen information is readable.
Internal layers are in the correct order.

For high-density designs, high-speed PCBs, and complex multilayer boards, this additional review is particularly important.

Step 10: Prepare the Final PCB Manufacturing Package

Once the files have been verified, organize them into a single manufacturing package.

A typical package may contain:

Project_Name/
├── Top_Copper.GTL
├── Bottom_Copper.GBL
├── Top_Soldermask.GTS
├── Bottom_Soldermask.GBS
├── Top_Silkscreen.GTO
├── Bottom_Silkscreen.GBO
├── Board_Outline.GKO
├── Drill.DRL
└── Fabrication_Notes.pdf

The exact file list depends on the PCB layer count and manufacturing requirements.

Compress the required files into a ZIP archive if requested by your PCB manufacturer.

Before uploading, make sure there are no outdated revisions, duplicate files, temporary CAD outputs, or unrelated documentation inside the archive.

Common Mistakes When Generating Gerber Files

Even experienced designers can make mistakes when preparing manufacturing data.

Missing Internal Layers

A multilayer PCB requires every necessary copper layer to be exported. Forgetting an internal layer can make the manufacturing data incomplete.

Incorrect Board Outline

An ambiguous or incorrect board outline can affect board dimensions, routing, tooling, and panelization.

Missing Drill Data

Gerber copper artwork does not replace drill files. Missing drill data can prevent the manufacturer from correctly fabricating holes and vias.

Incorrect Layer Mapping

Incorrectly assigning a silkscreen, solder mask, or copper layer can produce serious manufacturing errors.

Silkscreen Over Pads

Although the manufacturer may remove or clip silkscreen that falls within restricted areas, designers should avoid unnecessary overlap whenever possible.

Wrong Revision

One of the most common practical problems is sending Gerber files generated from an older PCB revision.

Always verify the revision before submitting the manufacturing package.

Failing to Specify Manufacturing Requirements

Gerber files do not necessarily communicate every manufacturing requirement.

Your order information or fabrication drawing may also need to specify:

Board thickness
Copper thickness
PCB material
Surface finish
Solder mask color
Silkscreen color
Controlled impedance requirements
Special tolerances
Via requirements
Edge plating
Countersinks or counterbores
Slots and cutouts

Gerber Files vs. Native PCB Design Files

Gerber files and native PCB design files serve different purposes.

Feature	Gerber Files	Native PCB Design Files
Main purpose	PCB fabrication output	Design editing and development
Layer representation	Individual manufacturing layers	Complete PCB design environment
Manufacturer compatibility	Very high	Depends on software
Editable design information	Limited	Extensive
Schematic information	Usually not included	May be included
Component libraries	Not normally included	Often included
Manufacturing artwork	Yes	Generated from design
Used for fabrication	Yes	Usually not directly

The native CAD file remains valuable because it is the source design. Gerber files are manufacturing outputs generated from that source.

For this reason, designers should retain the original PCB project files even after generating Gerber data.

Do You Always Need Gerber Files?

Gerber remains one of the most widely accepted formats for bare PCB fabrication, but it is not the only possible manufacturing-data format.

Some modern manufacturing workflows may accept additional formats or direct CAD-based data exchange. However, the exact requirements depend on the PCB manufacturer and production process.

Therefore, the safest approach is to check the manufacturer’s current fabrication-data requirements before exporting.

If a manufacturer specifically requests Gerber X2, Excellon drill files, ODB++, IPC-2581, or additional fabrication drawings, provide the requested format rather than assuming one format is universally preferred.

How Kingda Can Support PCB Manufacturing

Preparing accurate manufacturing data is only one part of successful PCB production. The next step is ensuring that the files are correctly reviewed and translated into a manufacturable circuit board.

Kingda can support customers through the PCB manufacturing process by reviewing manufacturing data and helping identify potential fabrication issues before production.

A professional manufacturing review can help identify problems related to:

Trace and spacing requirements
Drill sizes
Board outline
Layer configuration
Copper thickness
Surface finish
Solder mask
Silkscreen
Manufacturability
Special fabrication requirements

For complex projects, early communication between the designer and PCB manufacturer can reduce avoidable revisions, manufacturing delays, and unexpected production costs.

Best Practices for Creating PCB Gerber Files

To make your manufacturing workflow more reliable, follow these best practices:

Complete schematic and PCB Design verification before export.
Run DRC before generating manufacturing files.
Confirm the PCB layer stack and layer order.
Export every required copper, solder mask, silkscreen, and outline layer.
Generate the required Excellon drill files.
Use the manufacturer’s preferred Gerber format and output settings.
Open the files in an independent Gerber viewer.
Compare the Gerber output with the original PCB layout.
Verify the board outline and drill alignment.
Confirm the PCB revision before submission.
Include fabrication drawings and special instructions when required.
Package only the correct and current manufacturing files.

Frequently Asked Questions About PCB Gerber Files

What files are needed to manufacture a PCB?

A typical PCB fabrication package includes Gerber files for copper, solder mask, and silkscreen layers, a board outline, and drill data. Depending on the project, fabrication drawings, stackup information, impedance requirements, or other documentation may also be required.

Are Gerber files the same as PCB design files?

No. Native PCB design files contain the editable design database and may include schematics, component information, footprints, design rules, and other project data. Gerber files are manufacturing outputs representing individual physical layers.

Can I generate Gerber files from KiCad or Altium Designer?

Yes. Most professional PCB CAD tools provide manufacturing-output functions for generating Gerber and drill data. The exact export workflow varies by software version.

Do I need a separate drill file?

Yes, in most conventional PCB manufacturing workflows. Drill information is typically supplied separately from Gerber artwork, often using Excellon drill data.

Should I check Gerber files before sending them to a manufacturer?

Absolutely. A final Gerber review can catch missing layers, incorrect outlines, misplaced drill holes, silkscreen problems, and other export errors before they reach production.

Can Gerber files be edited?

Gerber files are primarily manufacturing outputs rather than source design files. While CAM software can inspect or modify manufacturing data, design changes should normally be made in the original PCB CAD project and then re-exported.

Conclusion

Learning how to generate Gerber files for PCB manufacturing is an essential skill for PCB designers, engineers, electronics developers, and hardware startups.

The process is straightforward when handled systematically: finalize the PCB Design, verify the layout, select the correct manufacturing layers, configure the Gerber output, generate drill data, export the board outline, inspect the files in a Gerber viewer, compare the output against the original design, and prepare the final manufacturing package.

The most important point is that generating Gerber files is not simply an export operation. It is the final verification step between your digital PCB Layout and physical PCB Manufacturing.

By maintaining a consistent workflow and communicating clearly with your PCB manufacturer, you can reduce manufacturing errors, avoid unnecessary revisions, and improve the reliability of your production process. Whether you are developing a simple prototype or a complex multilayer circuit board, accurate manufacturing data provides the foundation for successful PCB Assembly and reliable end-product performance.