Gerber Files Explained: Their Role & Need in PCB Manufacturing

The use of PCBs in electronic devices can be tracked down to as late as 1936. With the passage of time & the increasing reduction in technology size, the demand for compact and high-density PCBs is increasing. After designing your PCB, your contract manufacturer creates reliable PCBs from your design. But, in order for him/her to do that he/she requires a set of documents containing info on the copper layers, solder mask, legend, drill data, etc. This set of information is available through a no. of files called Gerber files provided by the PCB designer.

What are the Gerber Files?

Gerber files are open ASCII vector format files that have info on each layer of your PCB design. Circuit board objects, like copper traces, vias, pads, solder mask, and silkscreen images, are all shown by a flash/draw code and defined by a series of vector coordinates. PCB manufacturers use these files to translate the details of your PCB design into the physical properties of the PCB.

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Necessity of Gerber Files

The reason why Gerber files are a necessary part of PCB production is pretty obvious. Without the provision of Gerber files by the PCB designer,  PCB manufacturers won’t be able to fully understand all details of a PCB design file, as the Gerber file serves as both the reference and guideline. Gerber format file also describes the design requirements of each image of a circuit board and works for both bare board fabrication and PCB assembly.

Use In Bare Board Fabrication

For Bare Board Fabrication, the need for Gerber files is in both standard photoplotters and other manufacturing equipment desiring image data like legend printers, direct imagers, or AOI (Automatic Optical Inspection) equipment, etc.

Use In PCB Assembly

When it comes to PCB assembly, a stencil layer is present in Gerber format and part locations are present as well, which are a significant reference data for SMT assembly, thru-hole assembly, and mix of them.

Features

Gerber files follow the ASCII format & provides the following info to the manufacturer:

• Configuration parameters
• Macro and aperture dimensions
• Draw and flash command codes
• XY Co-ordinate locations for draw and flash commands

Different Versions of Gerber Files

Today there are 3 versions of gerber file available, they are as following:

1. RS-274-D: The oldest format of Gerber file by Gerber Systems Corp. It was in numerical control (NC) format and was compatible with different photo plotters back in the 1970s.
2. RS-274-X/X – Gerber: This format utilizes ASCII commands which are interpretable. These commands create a 2D vector graphic. It is also known as extended Gerber.
3. Gerber X2: The newest Gerber format with stack up data and attributes. It widely serves in many CAM software applications.