It is always exciting to travel to a new country and explore the culture, sample the food and meet new people. On these trips, it seems like every day is an adventure that ends with greater understanding, an altered palate or new friends.
However, to make the most of the experience, it is great to learn to speak the language. Otherwise, you may wind up spending most of your time in a state of confusion. This is similar to the confusion that can exist between you and your PCB manufacturer when your design files aren’t in the correct format which can delay your board’s manufacture or result in PCBs that do not meet your requirements. Fortunately, in PCB design, there is a global language, Gerber files, that is almost universally understood and utilized by PCB manufacturers.
The Gerber file format, RS-274-D, for printed circuit board specification was originally introduced in 1980. Since, there have been two major revisions, X1 and X2. The currently used formats are open ASCII formats for 2-D binary images and serve as the unofficial industry standard for PCB design files. As most contract manufacturers (CMs) employ computer-aided manufacturing (CAM) equipment cable of reading Gerber files, their use provides you with the greatest pool of manufacturers capable of fabricating your boards.
Altium Designer® , the most advanced and comprehensive PCB design software package available, makes it easy to generate and export Gerber files and also provides you with other manufacturing output solutions for CMs that prefer other file formats.
Gerber Files: The Universal Language of PCB Design
Although there is no actual standard PCB layout format that must be followed, Gerber files have occupied that position for decades. As such, most CMs accept Gerbers, typically in addition to a preferred proprietary format. This widespread acceptance is probably the most significant advantage of using Gerber files.
Typically, Gerber files are generated as a set of images consisting of separate files for the top and bottom layer copper, silkscreen and solder mask, as well as separate drill hole and mechanical files. The use of multiple files may present problems, as the files must be accurately aligned. There is movement in the industry to adopt a standard CAD file format to replace Gerbers; however, the ability of most PCB design software packages to generate and export Gerber files coupled with its compatibility with fabrication equipment among CMs cements Gerbers as the de facto PCB manufacturing output solution for the present.
Fig. 1 PCB and Gerber file mask
How to Generate and Export Gerber Files in Altium
AD 18 provides various user-selectable options for generating and exporting Gerber files for both X1 and X2 formats. For X1, these can be accessed on the Gerber Setup dialog from an OutputJob Configuration file (*.OutJob) or from the main menu in an active PCB document by clicking on File » Fabrication Outputs » Gerber Files.
Fig. 2 Gerber Setup dialog
As shown in the dialog above, the resolution for the Gerbers can be set to 0.01 mil through 1 mil via the General setup options tab. Additional options can be set using the other tabs, as described below.
Setup Options Tabs
- Layers - Here you can specify which layers to plot and mirror, as well as which mechanical layers to add.
- Drill Drawing - This provides options for including and setting up drill drawings.
- Apertures - You can specify which apertures to include as well as dimensions here. Apertures may be embedded, which is the default for RS-274X, and includes all apertures from the design. Alternatively, you have the flexibility to have more control over setting aperture options.
- Advanced - Use this tab to specify film size, position on film, plotter type, choose between a single file or multiple files and generate a DRC Rules Export file.
If you prefer to use the newer, X2 format the setup dialog with available options can be accessed from the main menu under File » Fabrication Outputs » Gerber X2.
Fig. 3 Gerber X2 dialog
As shown in Fig. 3, the X2 dialog allows you to select layers to plot, set resolution (NOTE: 2:6 is for 0.001 mil), set aperture tolerances and plotter type. In addition to the ability to generate and export Gerber files, AD 18 also provides other manufacturing output options.
Other Manufacturing Output Solutions
Altium makes it easy to generate and export Gerber files in either standard X1 or X2 formats. This capability ensures that you can find a CM that can read and create your design as it was intended. Additionally, Altium provides you with other manufacturing output solutions, such as ODB++ CAD files and IPC-2581 format for CM’s that prefer alternatives to Gerber files. You can also print out separate drill files, mask set, board stack and test point reports to assist your CM in fabricating your boards. AD 18 will even package your assembly files.
Fig. 4 Other manufacturing output solutions
Just as the quality of your trip depends on your ability to communicate effectively, the quality of your manufactured PCB depends on your CM understanding your design. Today, the most used language or design format is Gerber files. Therefore, for the best opportunity to have your design intent understood by a CM, your PCB design, and development software must be able to generate and export Gerber files. If you are ready to check out these options and more with Altium, you can get a free trial here.
For more information on how to generate and export Gerber files in Altium , talk with an Altium PCB design expert.
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