How important are Gerber files in PCB manufacturing?

September 5, 2025

Gerber files are the most widely accepted design file format for manufacturing and assembling printed circuit boards (PCBs). They ensure an efficient manufacturing process by standardizing the transfer of design data between engineers and PCB manufacturers. Once the circuit design is finalized and the order is placed, the contract manufacturer will request these design files to accurately produce the PCBs.

Any errors in the provided data will inevitably lead to board defects, additional costs, and delays. To avoid these consequences, Gerber files play a critical role in PCB manufacturing.

What Are Gerber Files? What Information Do They Include?

Gerber files are a set of ASCII vector format files that define PCB design specifications. They are generated using electronic design automation (EDA) or computer-aided design (CAD) tools and provide information such as board configuration parameters, aperture descriptions, XY coordinate positions, and plotting instructions. Configuration details include the dimensions and shape of the PCB to be manufactured. Each layer of the board is recorded in a separate file, defining elements such as copper traces, pads, vias, solder mask, silkscreen, logos, and more. The XY coordinates of each geometric shape are marked in the Gerber files, and instructions are used to draw these shapes on the physical board.

The basic components of Gerber files include: board size, outline, top assembly, top silkscreen, top solder mask, top paste, top copper, internal signals, inner layers, bottom copper, bottom paste, bottom solder mask, bottom silkscreen, bottom assembly, and manufacturing information (providing details such as layer stack-up, drill data, and cut specifications). The file extensions for Gerber files generated by computer-aided manufacturing (CAM) tools can be customized by the user. Common naming conventions include ".TOP" for the top layer, ".BOT" for the bottom layer, and ".drl" for drill data.

The Importance of Gerber Files in PCB Manufacturing

PCB designers must use EDA tools compatible with the PCB manufacturer’s system to create Gerber files. Mismatches in format or tool versions may cause delays in the manufacturing process.

The primary goal of Gerber files is to ensure reliable PCB orders are delivered on time. Using Gerber files in PCB manufacturing offers several benefits, including:
Providing intricate design details that help manufacturers produce high-quality boards.
Enabling contract manufacturers to verify precise dimensions, pad locations, trace widths, and silkscreen legends.
Significantly reducing potential manufacturing errors through accurate data.

They are compatible with various CAM tools used by PCB manufacturers. Gerber files can be easily exported from most EDA tools, ensuring a smooth transition from design to production. Additionally, the flexibility of the data format allows contract manufacturers to employ different fabrication and assembly techniques, supporting advanced technologies.

The standardized format of Gerber files is essential for establishing a flawless PCB manufacturing process. These files are easy to read and facilitate collaboration among design engineers, layout specialists, and assembly technicians, thereby minimizing confusion and rework throughout production.

Typically, contract manufacturers use Gerber files for Design for Manufacturability (DFM) checks to evaluate production yield. These files are also used to create fixtures for board inspection and testing, contributing to quality control in PCB production.

Gerber File Versions and Other Output Formats

The type and number of Gerber files generated depend on the specifications and complexity of the board. Different Gerber file formats have varying data structures, but all serve as templates for PCB fabrication.

RS274-D is a standard Gerber file format that uses a numerical control (NC) format consisting of XY coordinates and plot codes, with the extension ".gbr". It was widely popular initially but required manual aperture code assignment to generate precise Gerber files, leading to the development of extended Gerber formats.

RS274-X is a revised version with the extension ".gbx". It uses an ASCII format that integrates the four major components of Gerber information (configuration parameters, aperture list, XY coordinates, and plotting instructions) into a single file. In this format, aperture positions are updated automatically.

Gerber X2 is the latest file version, incorporating additional data such as layer stack-up details, via and pad properties, impedance-controlled traces, etc. Supported extensions include ".top", ".bot", and others. This format is backward compatible with RS274-X but includes extensive manufacturing data, significantly reducing file errors and data ambiguity.

Open Database (ODB++) is another data exchange format that consolidates all information required to define PCB layers into a single file. It allows designers to capture all data needed for DFM checks, including board stack-up, bill of materials (BOM), dimensions, and drill details. It is supported by major CAM and DFM tools.

IPC-2581 is the latest standard for organizing PCB data and exchanging information from CAD to CAM systems during manufacturing and assembly. It is an open standard for data transmission without manual intervention. Based on XML, this file format provides all manufacturing data to CAM systems, allowing direct extraction of design data without interpretation.

Gerber files are universally adopted in the PCB manufacturing industry for data transmission, supporting high-volume mass production of PCB products. The latest version, Gerber X2, is highly favored among manufacturers for its ability to deliver high-performance and reliable PCBs. These files reduce manufacturing errors, improve efficiency, and accelerate time to market.