Gerber File Ultimate Guide-A Beginner’s Guide to Gerber

1. Circuit Board Vector In Gerber File

1. 1 So, What Are Printed Circuit Boards (PCBs)?

Primarily, PCBs are boards made of tough insulating material upon which circuits for electronic components (e.g., resistors, ICs, capacitors) are mounted.

The circuits mounted on the boards are often drawn using thin strips of conducting materials like copper overlaid with additional layers of circuits or insulating material.

As I noted in the introduction, they are the frameworks for nearly all modern electronics. Put: that’s why you need to know them well enough.

The invention of PCBs and Integrated Circuits (ICs) was a revolutionary step in reducing the size of modern electronics.

1.1.1 Do You Need PCBs? 

Even though the earliest uses of PCBs can be traced back to 1936(Harper, 2004), it is hard to imagine any modern commercially viable electronic gadget/project that will not employ PCBs.
You might have also noted that PCBs are the backbone of nearly all modern electronic devices.
So, even though the earliest uses of PCBs can be traced back to 1936(Harper, 2004), it is hard to imagine any modern commercially viable electronic gadget/project that will not involve learning about electronics or producing electronics. Therefore, you will inevitably need to learn about PCBs willy-nilly.

1.2 What Does “Gerber” Or “ Gerber File Format” Mean?

According to UCAMCO (the company that currently owns the rights to the Gerber File format), the Gerber file format is a de facto standard for PCB-designed data storage or transfer.

It can further be described as an open ASCII vector format for representing 2D binary images. A Gerber file describes and communicates the constituents of a PCB image, such as the number of copper layers, solder masks, and many other attributes.
Gerber files also act as input files to PCB printing devices like photo-plotters and Automated Optical Inspection (AOI) machines to print or compare circuit board images.

1.2.1 Gerber Formats

The three generations of Gerber are:

• Standard Gerber (Also known as RS-274-D) – the oldest form of Gerber
• Extended Gerber (Also known as RS-274X)
• Gerber X2 –The newest kind of Gerber

Chapter three will elaborate more on these formats. For now, let’s try to grasp the simple definitions.

1.3 Here’s Where Gerber Meets PCBs 

The preceding chapters will discuss the compositions of Gerber files and methods of manipulating Gerber files.

Note:

     ►An important point you need to note is that circuit boards were originally not made with CAD or CAM software applications. It is logical to c, include that PCBs are not limited to circuit boards drawn from CAM software applications.

With the increased use of PCBs came the demand for standards that could guide the production of circuit boards. Gerber emerged as a standard that could ease the process of developing PCBs. So, let’s try to understand what a “Gerber” defines.

     ►In 2014, UCAMCO declared the Standard Gerber as “technically obsolete” and gave preeminence to Extended Gerber over Standard Gerber. This is because aperture definitions for the standard Gerber were not standardized. 

2. The Gerber File

2.1 What Is A Gerber File?

A Gerber file contains information that guides the production of a PCB. As you might have observed, the Gerber file format is a de facto standard that defines 2D binary images using open ASCII vector format.

Modern Gerber files may also include metadata (data about other constituting data within a file) like solder mask, legend/silk, and number of copper layers, among other relevant printing information.

PCBs are made from Gerber 274-X data and NC drill files.

Each Gerber file corresponds to one layer in the physical board – the component overlay, top signal layer, bottom signal layer, solder masking layers, inner layers, etc.

Because there are so many different versions of PCB files in use today, we require our clients to provide us with a full set of Gerber and NC drill files to avoid version conflicts.

When submitting Gerber files for a quote or an order, it’s handy to have a simple text file accompanying the data explaining the requirements that do not appear in the Gerber files.

Important information that is not often easily identifiable includes solder mask and silkscreen colors, penalization requirements, pad finish, board thickness, and copper weight.

Also, any special PCB requirements or features such as slots or cutouts. Placing details like this on a mechanical layer is a good place for such data, Or in a text file.

A Gerber Setup dialog provides tools to configure your Gerber file output options completely.

At its inception, Gerber emerged as a standard that could guide the production of circuit boards among Engineers.

But because Gerber defined an open standard, it held a high generality and low particularity.
Gerber standards did not lay down fixed guidelines that could restrict the production of PCBs at their inception.
As a result, Gerber was easily adopted by various PCB designers and engineers in designing electronic circuits on boards.
This boosted its adoption and popularity among PCB designers and engineers.

2.1.1 Here Is Why You Need To Care About Gerber Anyway…

In 2015, UCAMCO estimated that about nine in every ten PCB productions are presented in Gerber form.

The increase in the production of electronic devices is parallel to PCBs produced.

This brings about a consistent and constant push for circuit improvements on Gerber files.

Because of this constant need to improve current designs and efficiency, studying Gerber files could make your skills relevant to PCBs.

2.2 Gerber File Viewer

A Gerber file viewer is software that allows you to view the contents of a Gerber file. Currently, there are a variety of Gerber viewing tools on the market.

Some of these tools work by installation (much like traditional software applications), but most work online without being installed on one’s computer. They allow you to upload files and view the Garber files online.

2.2.1 Key Features To Consider For Gerber File Viewers

To choose s good Gerber file viewer, you might need to consider the following three features:

1. Updated file format support: An ideal Gerber file viewer should be able to support popular modern file types like HPGL/HPGL-2 and Excellon, among others.
2. Support precision in viewing: Good Gerber viewers should also include features for zooming and precision measurements so that users can easily check through circuits and rectify errors.
3. Broad printer compatibility: Gerber file viewers should also be compatible with various printers. Besides, it should also give room for various printing options for various printers.

2.2.2 The Best Gerber Viewer Tools

Of all the several Geber viewing tools available in the market, the following three tools are currently the top-rated tools for viewing Gerber files:

2.2.3 The Online Gerber Viewer

It is compatible with Gerber274X and Excellon 1 and 2 file formats. This tool also allows you to zoom in whenever you need to check your boards for design errors.

2.3 The EasyEDA Gerber Viewer

EasyEDA is an awesome online Gerber viewer with nearly all the features of the Online Gerber tool. But unlike the Online Gerber, EasyEDA allows you to view the layers of an uploaded/imported PCB, zoom through and choose the color for the PCBs.

It also has some statistical features that allow you to compare the shapes and sizes of the holes and dimensions of the board. Once you have done this, EasyEDA will offer you the option of sharing your files using a URL.

2.4 The Numerical Innovation Gerber Viewer

Numerical Innovation is simply awesome. This tool has checked all the highlighted features as important aspects of an ideal Gerber Viewer.

Are you looking for clarity? Check that. How about the ability to zoom images?

Please check that. Also, please check file compatibility. Honestly, an experience with Numerical is seamless.

The Eagle and the Altium-generated files from Seed Studio are very easy to use. For beginners, this could be an indispensable tool.

In the following chapter, we’ll examine the Gerber file extensions available in the industry and then see how to manipulate Gerber files.

3. Gerber File Extensions (.gbr /.GBR)

Gerber files are often associated with the file extension “.gbr” or “GBR.” However, other extensions like “.GBX,” “.Top,” and “.BOT” are also used to define Gerber files.

 And even then, the “.gbr” extension does not exclusively apply to PCB Gerber files. Sometimes this extension is still used by other image editing software applications like GIMP to represent the applications’ image brush files.

3.1 So, Why Do We Have Such A Variety?

Do you still recall the three highlighted generations of the Gerber file format? That is where we will find the entire story of Gerber File extensions. Let’s begin with:

3.1.1 The Standard Gerber (Also Known As RS-274-D)

This was the oldest form of Gerber file representation that Gerber Systems Corp designed as a Numerical Control (NC) format to drive the photo plotters of the 1960s and 1970s.

The RS-274-D supported basic plotting capabilities, such as drawing trucks. However, it did not distinctly define the coordinates and margins of the drawing (Electronic Industries Association, 1979).

With time, the Standard Gerber became unpopular and was eventually revoked by its developers in 2014. Even then, the Standard Gerber was responsible for the origin and popularity of the “.gbr” file extension.

3.1.2 Extended Gerber (Also Known As RS-274-X of X-Gerber)

This form of Gerber was introduced in 1998 by UCAMCO. It combines human-readable ASCII commands to generate a 2D vector graphic.

X-Gerber also incorporated metadata to define graphics. It is associated with the “.gbr” and “.gbx” file extensions.

3.1.3 Gerber X2

This is the latest Gerber format for files. It includes improvements from all its predecessors. This file format supports all the extra vendor extensions like “.top” and “.bot.” This file format is compatible with most modern CAM software applications.

Now, because we have already looked at some software tools that can help us view Gerber files, it’s time to take some time and get our hands dirty manipulating Gerber files. Are you ready? In 5, 4, 3, 2, 1…

4. Hands On The Gerber File

4.1 Creating A Gerber File Using Eagle 3.55

Choosing a reliable manufacturer is an important thing when you after your design; there are some factors you need to take into consideration:

   1. Can I help you quickly check if there are any problems with your design?

   2. Can they meet any special requirements in your design?

   3. Lead-Time, Quality, and then the Price is acceptable.

4.1.1 Gerber File

Before we start the next step, you’ll need to download another definition file: the CAM file.

EAGLE provides a CAM job file, creating your Gerber easily file for a 2-layer board. Please follow these steps:

First, download these files：

   1, eagle to gerber1.doc;(39.5 KB)

   2, Eagle user brochure.pdf; (289 KB)

   3, IPC-a-600.pdf(1.50 MB )

1. Load your board on the screen.

To do this from the Eagle Control Panel, click on File/Open/Board and select the board you will use. 

2. Click on the Icon on the top Toolbar that says ULP.

When the dialog box appears, select the ULP file called DRILLCFG.ULP from the ULP directory. In a matter of seconds, on the command line, you will notice a message saying ULP has finished.

3. Now click on the Icon that stands for the CAM Processor.

This will load the CAM Processor Screen. From this screen click on File/Open/Job (when asked to save “Modified Job” reply NO) and select the CAM job called GERBER.CAM from the CAM directory and click OK.

4. Now click on the button that says Process Job.

This will prompt you with two messages. The first message will be “Delete the $$$ file after process.” This is a dummy file that EAGLE creates. Click OK. The second message will be “More than one signal layer Active.” Click OK to this message as well. Depending on the size and complexity of the board, the entire process will take a few minutes or hours.

5. When the CAM Processor stops all processes, it has finished.

This process created several files that will have the same name as your board with different extensions:

   .WHL Aperture Wheel File.PLC Silk Screen Component side

   .CMP Copper Component side.STC Solder Stop mask Component side

   .SOL Copper Solder side.STS Solder Stop mask Solder side

Then, you need to zip the following files and deliver them to the PCB Manufacturer.

Gerber Files	Extension
Top (copper) Layer	.GTL
Bottom (copper) Layer	.GBL
Top Overlay	.GTO
Bottom Overlay	.GBO
Top Paste Mask	.GTP
Bottom Paste Mask	.GBP
Top Solder Mask	.GTS
Bottom Solder Mask	.GBS
Keep-Out Layer	.GKO
Drill Drawing	.GD1
Drill Guide	.GG1
Internal Plane Layer1,2,…,16	.GP1, .GP2, … , .GP16

*The GTP file isn’t necessary for the PCB fabrication because it is used to create a stencil(if your design had SMD parts).

4.1.2 Excellon Files

(Make sure you have done steps 1 and 2 before proceeding with Excellon files)

• Directly from the CAM processor, click on File/Open/Job and select the CAM Job called EXCELLON.CAM from the CAM directory, then click OK.
• Now click on the small button that says Process. This will begin the EXCELLON file generation. Normally, this process only takes a few seconds.
• The following files are created when the process ends.

.DRL Tool Rack File.DRD Excellon. Output.DRI Drill Information file

ICONS

CAM Processor User Language Program (ULP)

Adding Layers to the existing GERBER.CAM file

(Refer to your EAGLE 3.55 manual page 86.

The first page of this document teaches you how to create all the necessary Gerber files for a 2 sided board. But due to the growing demand for more than 2 layers, wne decided to add this portion to this document.

Initially, GERBER.CAM generBy modifying the Gerber, ates all of the apertures needed to make a two-sided board, by modiess, we can easily add more steps to the CAM processor to take care of our additional layers.

Let’s begin:

1. From the EAGLE control panel, click on File/Open/Board and select the board you are interested in.

2. Click on the CAM processor ICON.

3. Now click File/Open/JOB and select the file GERBER.CAM from the CAM directory. If Eagle prompts you to save the current process, click NO.

4. Notice on the CAM processor screen a field called SECTION. If the section called “Generate a Wheel file” is not visible, click on the down arrow at the end of the section and select it.

5. You will notice the layer list on the right-hand side of the CAM processor screen. Tag the additional layers you wish to include: Inner layers or the bottom silkscreen layers (BPlace and BName). DO NOT UNTAG ANY OF THE OTHER LAYERS. Click on File/Save Job to save what we have done. I would recommend giving this CAM job a different name. For example, 4Layer.cam)

6. After tagging all the necessary layers, click the SECTION down arrow and select the last section called Solder Stop Mask SOL.

7. Click on the ADD button.

Eagle will ask you to name the new section you are creating. You can give it any name you feel comfortable with; for example, call it Inner Power Plane VCC, INNER SIGNAL Layer 2, or BOTTOM SILK SCREEN). Click OK when done.

8. Now select the appropriate layer for this section. An inner power plane (for example, $GND) selects that layer alone.

If it’s a bottom silkscreen layer, tag the Dimension, BPlace, and BName layers. If it’s a regular signal layer, combine it with PADs and VIA. MAKE SURE NO OTHER LAYERS ARE TAGGED.

9. Change the name of the output. Use the table at the bottom of this page as an example.

10. Create a new section for every new layer needed. Repeat steps 7, 8, 9, and 10 for every new layer.

Go to step 4 on page number 1.

Layers	Extension
Supply Layer	Supply layer only ($GND).GND
Signal Layer	Signal layer, Pad, Via.LY3
Bottom Silk screen	Dimension, Bplace, Bname.PLS

4.2 How To Export Gerber Files From Altium Designer

4.2.1 Generate Gerber

1: Select “File” menu, >> “Fabrication Outputs” >> “Gerber files”

2: in the dialog box, specify the parameters for measuring the PCB.

3: Select the layers: For a 2-layer board, uncheck layers G1, G2, and G3 ….

4: Check the Embedded Apertures

5: Once you affirm all settings are fine, click “OK” to generate Gerber.

4.2.2 Generate Excellon

1: Select “File” menu, >> “Fabrication Outputs” >> “NC Drill files”

2: Adjust the parameters to fit the parameters for the Gerber File and click “Ok” to generate.

3: Compress all the files generated into a .zip file and send them for Manufacturing.

4.3 Converting Gerber Files (“.gbr”) to “.pcb” files

4.3.1 What Are “.pcb” Files?

In a nutshell, the “.pcb” file extension is associated with CAD (Computer Aided Design) software application-generated files.

After designing your circuit through software applications like the ULTRIUM Designer, these files are generated to store information that can guide the creation of circuit boards.

4.3.2 Why Is This Important?

Though designing engineers can be comfortable sharing data in their PCB format, as it is easy to comprehend; manufacturers of PCBs might require additional guidelines on factors like drilling. These parameters may hinder successful WellPCB. Wne will provide you with one-stop service and high-quality products. You can send us the documents you need to make and get a quote immediately! What are we waiting for? We have ten years of PCB manufacturing if unchecked.

4.3.3 How Do I Convert It?: 12 Steps To Conversion (Using LinkCAD)

• First, download LinkCAD from their official site here.
• Next, install it on your computer (like any regular program). This will allow you to try the software for five days.
• Run LinkCAD on your computer.
• On the opening screen, click “Import Format” and select the PCB file type (the type you intend to convert) from among those listed in the drop-down.
• Select “Gerber” from among the “Export Format” drop-down.
• Uncheck the “Skip options” dialog option.
• Check the “Ignore text” menu option from the “GDSII Import Options” window.
• Modify any additional preferences you might need to modify within the “Export Options” menu that appears.
• Browse within your computer and choose the “PCB” file to convert.
• Click on the “Next” button in the window that appears and waits for the file to be converted.
• Check within the folder having the original “PCB” file for the converted Gerber files.
• If everything is okay, click on “Finish” and exit.

What Should The Gerber File Contain?

Manufacturers rely on Gerber files to make PCBs. These files hold instructions and settings for making PCBs, which are then laminated, etched, plated, drilled, and milled. 

Additionally, you’ll find information such as the size, position, color, and shape of the PCB. The Gerber files also have a section with guidelines on the colors of every element.
Here are some other specifics you’ll find in a Gerber file. 

PCB Dimensions

The board dimensions include the PCB board outline and dimensions. It also includes locations for the connector cutouts, displays, and components. 

Copper Traces

PCB boards use conductive copper to enable electrical data travel. Copper traces are the tracks in the boards along which these data signals travel. These copper traces have pads on the top and bottom layers. 

Panelization

You’ll likely find a Gerber file with panel layout guidelines if a PCB design features many copies of a similar circuit. Usually, the Gerber files are put in one panel, ready for mass production.

It’ll feature the panel layout and how many circuit copies are in each panel.

Copper Connections

Since the entire PCB needs full electrical conductivity, the copper connections must be continuous and cover the whole board. The Gerber file contains the copper pour dimensions for both layers. 

Solder Mask Layers (.GTS & .GBS)

Found on the top and bottom, solder mask layers keep copper traces from getting electrical shorting. They also protect pads and other components. They are in the same Gerber file as solder mask coverage. 

Silkscreen Layers

Silkscreen layers show where the manufacturer will place components in the assembly stage. The Gerber file with this information also has label sizes, symbols, and locations, as well as silkscreen markings for the bottom and top layers. 

Drill hole guidelines

Precise drill holes are vital for PCB function. The Gerber file contains guidelines on where to drill holes, their patterns, and sizes.

Usually, some details show drill bit target areas to ensure precision during drilling. These drill bit markings prevent wrong drill hole marking. 

Vias

A via is a tiny opening running through the PCB that allows conductivity between PCB layers. Gerber files should contain hidden and buried vias and guidelines on their positioning and sizes.

Surface Treatment

To finish off, Gerber files might have details on PCB surface finishing for the entire board or only sections of it.

PCB surface treatment determines how the PCB performs, and components respond to soldering.

What Is The Difference Between Gerber And CAD Files?

Gerber and CAD files share the similarity that they both contain the PCB design layout. However, their difference contributes to when and where manufacturers apply each. 

One of the standout differences is function. 

Gerber files’ portability makes them more suitable for PCB fabrication, while CAD files may have additional files missing in Gerber files that make them more suitable for intricate PCB design. 

Here are other differences between Gerber vs. CAD files.

Output Format

As stated, Gerber files’ output formats are portable, making them easy to debug and human-readable. This also means they are ready for fabrication at any time.

Comparatively, CAD files’ output formats are readable by machine. They are comprehensive and mostly best for design.

More Information

While Gerber files are an industry standard, CAD files may contain more information that you might not find in Gerber files. Detailed information, such as electrical data, is sometimes only available in CAD files. 

Generating Software

CAD software generates CAD files, whereas CAD or CAM software can generate Gerber files. You’ll find all the design information of a PCB, whereas you will find a graphical representation of individual layers of the PCB.

Conclusion

The common problem of missing lists like the aperture or tools list often follows this challenge.

And then, the challenge of compatibility within CAM software applications would make this task way too hard.

However, this process has become highly streamlined over time. Thanks to advancements in CAM software applications and file representation like Gerber, developers and designers can now fabricate PCBs from fabrication datasets.

Now, this creates an interesting loop, electronics depend on PCBs; PCBs depends on the Gerber file.

So, for electronics to thrive, PCBs must thrive; for PCBs to be great, Gerber designs must be outstanding.

For Gerber to improve, there must be an increased demand for improved electronics. You see it? Do you notice a funny loop?

That is why the future of electronics is likely to be filled with Gerber files on ends. Besides learning on your own, what other things can you do?

Hey! I am sure you might love this part.

After reading our guide, you might have developed an interest in learning more about Gerber files and PCBs.

Feel free to visit our official website and peruse our collection of tricks that can transform you from a beginner to a pro.