After completing a printed circuit board (PCB) design, the next critical step is preparing the manufacturing files for production. PCB manufacturers cannot directly fabricate a board from a raw CAD project because different PCB design software uses different native file formats. Instead, manufacturers rely on Gerber files, which are the universal standard used to describe the PCB layers, drilling information, solder masks and silkscreen details required for fabrication.
For beginners, learning how to make a Gerber file for PCB manufacturing may initially appear complicated. However, once the process is understood, Gerber generation becomes a routine and essential part of PCB design workflow. Gerber files serve as the direct link between the virtual PCB layout created in design software and the final physical circuit board produced by the factory.
In this guide, we will explain step by step how to create Gerber files correctly and prepare them for PCB manufacturing.
What is a Gerber File?
A Gerber file is a vector-based 2D manufacturing file that represents a specific layer of a PCB design. Each PCB layer is exported separately so that the fabrication facility can clearly understand how every section of the board should be manufactured.
A complete PCB project generally includes several Gerber files, such as:
Top copper layer
Bottom copper layer
Solder mask layers
Silkscreen layers
Drill data files
These files contain the precise instructions needed for copper etching, solder mask application, silkscreen printing and hole drilling. Because of their importance in PCB production, understanding how to make a Gerber file for PCB fabrication is a fundamental skill for electronics engineers, hardware developers and PCB hobbyists.
Why Gerber Files Are Important
Many PCB beginners ask why manufacturers cannot simply use the original PCB design file instead of requesting Gerber files. The answer mainly relates to compatibility and standardization.
PCB design tools such as KiCad, Altium Designer, Eagle and OrCAD all use their own proprietary project formats. Since manufacturers work with files from countless different software platforms, supporting every native design format would be highly impractical.
Gerber files solve this problem by acting as a universal manufacturing standard accepted throughout the PCB industry. Regardless of which PCB software is used during design, the exported Gerber files can be interpreted by almost any fabrication factory worldwide.
Learning how to make a Gerber file for PCB production ensures that the manufacturer receives accurate, readable and production-ready data. Gerber files clearly define where copper traces should be etched, where holes should be drilled and how silkscreen markings should appear on the final PCB.
In many ways, Gerber files function as the communication language shared between PCB designers and PCB manufacturers.
Step-by-Step: How to Make a Gerber File for PCB
1. Finalise Your PCB Design
Before exporting any Gerber data, the PCB layout must be fully completed and carefully checked for design errors.
Areas that should be reviewed include:
Proper electrical connectivity
Correct trace widths and spacing
Accurate drill hole dimensions
Correct placement of component labels and reference text
Running a Design Rule Check (DRC) is highly recommended to ensure the PCB layout complies with manufacturing requirements before file generation begins.
2. Open the Gerber Export Tool
Most PCB design software includes a dedicated Gerber export or CAM processing function.
Opening the Gerber Export Tool
KiCad: Plot → Gerber
Altium Designer: File → Fabrication Output → Gerber Files
Eagle: CAM Processor → Gerber
After opening the export window, you will be able to choose which PCB layers should be included in the final Gerber package.
3. Select the Necessary Layers
For a standard two-layer PCB, the following manufacturing layers are typically required:
Top Copper
Bottom Copper
Top Solder Mask
Bottom Solder Mask
Top Silkscreen
Bottom Silkscreen
Drill File
If your PCB design contains multiple internal copper layers, those layers must also be exported.
Selecting the correct layers is an important part of learning how to make a Gerber file for PCB manufacturing because omitted files can lead to incomplete board fabrication.
4. Define File Naming Conventions
Using proper file naming conventions helps manufacturers quickly identify each PCB layer.
Common Gerber extensions include:
.GTL — Gerber Top Layer
.GBL — Gerber Bottom Layer
.GTS — Top Solder Mask
.GBS — Bottom Solder Mask
.GTO — Top Silkscreen
.GBO — Bottom Silkscreen
.TXT / .DRL — Drill File
Maintaining clear and organized naming structures also helps reduce confusion during future design revisions.
5. Configuration of the Right Output Parameters
Correct export settings are essential when generating manufacturing-ready Gerber files.
Important parameters include:
Units: Use either millimeters or inches consistently.
Coordinate Format: Common formats include 2:5 or 4:6 precision.
Zero Suppression: Leading or trailing zero suppression is commonly used unless otherwise specified by the manufacturer.
Coordinate Mode: Absolute coordinates are generally preferred because they improve manufacturing accuracy.
Improper export settings may cause scaling or positioning problems during fabrication.
6. Generate Drill Files
In addition to Gerber files, manufacturers also require drill data, which is normally exported in Excellon format.
The drill file defines:
Hole diameters
Hole locations
Tool information
Without accurate drill files, plated through-holes and vias cannot be manufactured correctly. Therefore, drill generation is a critical stage in the PCB manufacturing workflow.
7. Verify with a Gerber Viewer
After generating the Gerber package, the files should always be inspected using a Gerber viewer before being sent to production.
The verification process helps confirm that:
Copper traces appear correctly
Drill holes align properly with pads
Silkscreen text does not overlap solder pads
Layer polarity and orientation are correct
Many free Gerber viewers are available online and can help detect problems before manufacturing begins.
Careful inspection at this stage can prevent costly fabrication mistakes and production delays.
8. Compress into a Single Zip File
Once all files have been checked and confirmed, place the Gerber files and drill files into a single ZIP archive.
Most PCB manufacturers prefer receiving compressed file packages because they simplify file management and reduce the possibility of missing data during upload.
After compression, the PCB manufacturing files are ready for submission.
Conclusion
Understanding how to make a Gerber file for PCB manufacturing is one of the most important skills in electronics design and PCB development. Gerber files convert a PCB layout into a standardized production format that fabrication factories can accurately process.
From completing the PCB layout and exporting the required layers to generating drill files and verifying the output with a Gerber viewer, every step plays a critical role in ensuring successful PCB fabrication. Proper attention to file settings, layer organization and final verification can greatly reduce production errors and improve manufacturing quality.
Whenever uncertainties arise regarding file requirements or fabrication standards, it is always recommended to communicate directly with the PCB manufacturer before submitting the final files.
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FAQs
Which software is commonly used to produce Gerber files?
Most PCB design software supports Gerber export functionality, including KiCad, Altium Designer, OrCAD and Eagle. Gerber generation tools are usually found within the CAM processing or plotting sections of the software.
What number of Gerber files does a simple two-layer PCB require?
A standard two-layer PCB typically requires at least six Gerber files covering copper, solder mask and silkscreen layers, along with one drill file.
Do firms accept native CAD files, rather than Gerber?
Some PCB manufacturers may occasionally accept native CAD files, but Gerber files remain the industry-standard format for professional PCB fabrication because of their universal compatibility and manufacturing reliability.
