Printed circuit boards (PCBs) have been around since 1936. They are still an integral part of several advanced circuits. The demand for compact-sized and high-density printed circuit boards is increasing. This is owing to the increasing use of small devices, which demand compact-sized chips. Nowadays, achieving the smallest PCB sizes is easy owing to the increased utilization of advanced manufacturing technologies. Although PCB manufacturers experiment with various dimensions, materials, and technologies, they also rely on Gerber files to oversee the production of printed circuit boards. What are Gerber files? How do they add value to any PCB fabrication process? This post concentrates on these and various other aspects of Gerber files and their importance.
Gerber Files – Why Are They important
Gerber file is one of the important file formats used during the design of circuit boards. These files were initially developed by the company called Gerber Systems Corp, a subsidiary of Gerber Scientific. It describes the features of the circuit board such as a number of solder mask layers, conductor layers, legend, drill data, and so on.
Typically, the printed circuit boards are designed in computer-aided design (CAD) systems, which utilize manufacturing data to create two-dimensional or three-dimensional designs of the PCB. The data needs to be entered into these systems to produce these designs. It may sound easy, as someone may perceive it as a system that will automatically produce designs on entering the data. But that is not the case because users have to refer to guidelines and references mentioned in the Gerber file while entering the data. A Gerber file is developed such that it elaborates the requirements in each stage of the product development. These files are used for both processes— PCB fabrication and PCB assembly.
Get Introduced to 4 Important Features of Gerber Files
A Gerber file follows an ASCII vector format, and it provides the following information:
- Configuration parameters
- Macro and aperture dimensions
- Draw and flash command codes
- XY Coordinate locations for draw and flash commands
There is a Gerber file for each drill span and image layer of the circuit board. These files are archived in a single file and sent to the printed circuit board manufacturer. At times, a printed circuit board manufacturer may receive more than eight files for a standard two-layer PCB, and more. They may include the following:
- The image of the copper trace to be included on the bottom side of the PCB.
- The image of the copper trace to be included on the top side of the PCB.
Similarly, there would be two files each for the images of solder mask and silkscreen to be applied on the bottom and top of the PCB. There will be files indicating several drill holes, their location and purpose. Many times, surface mounted and plated through-holes are indicated in different files. There will be a detailed board outline describing machining processes to be conducted, internal cutouts to be made, and more. Also, there is a file included called README, which states the purpose of aforementioned files.
A Brief Discussion on Different Types of Gerber File Formats
The following are the two popular Gerber file formats:
- Rs-274-D: This is the oldest format of Gerber file designed by Gerber Systems Corp. The file was represented in the numerical control (NC) format, and it was compatible with different photo plotters used in the 1970s. There were several drawbacks of this format, which finally led to its revoking in 2014. This format is known as the Standard Gerber.
- RS-274-X of X-Gerber: This Gerber file format is being used since 1998. It utilizes ASCII commands which are interpretable. These commands are combined to create a 2D vector graphic. The format is also referred to as Extended Gerber.
- Gerber X2: The format is designed for most advanced CAM software applications.
Gerber files can be easily generated using several software applications such as Altium Designer, Cadence, EAGLE, and so on. If you do not have any of these software applications, then you can seek help from a PCB manufacturer whom you plan to work with. Many of them will help you create Gerber files from scratch. Rigiflex is one of the leading PCB manufacturing service providers in the US; they assist their clients to create Gerber files from scratch if they do not have it. The company accepts files in different formats.
