Gerber Files problems

Solution To The Most Common Gerber Files Problems

Gerber files are digital blueprints meant to facilitate the process of manufacturing and building Printed Circuit Boards (PCBs) layer by layer. Most of the PCB design softwares are able to generate these files. Such software is EAGLE which we (RUSHPCB) recommend that you use since it is powerful and free all over the world. Creating Gerber Files which can reflect what will be manufactured is a big challenger even to experienced PCB designers.

However, through experience and long time expertise in the PCB world, we have a lot to share with you. In this blog post, we will introduce to you the most problems facing Gerber Files and give you the solutions to the problems. We are one of the best PCB manufacturers, assemblers, designers and fabricators in the world. Please pay us a visit at and interact with one of our sales representatives or experienced engineers.

Missing Excellon Drill files

An Excellon drill file is used to determine the size and location of a hole that is about to be drilled. Both plated and non-plated holes are included in one dill file but with entirely different tool numbers.

What should be provided in an Excellon Drill File?

  • Excellon format
  • ASCII code (Odd/None)
  • 4 Trailing Zero Suppression
  • English Unites
  • No Steps and Repeats

It is, therefore, crucial to ensure that all the above formats and requirements are provided in your drill file to avoid disappointments. All layout packages should produce an Excellon drill file. However, if you have problems creating one, we are here to serve you and help you achieve your design specifications with minimal errors. Kindly pay us a visit at RUSH PCB Ltd

Missing Aperture List

In Printed Circuit Boards world, an aperture list is used to specify what tool should be used in what stage and the corresponding location where the tool will be used. In this context, the Gerber File specifies what should be done and in what location. To ensure that your Gerber File works effectively, it is paramount that you send a single comprehensive aperture list for all the layers rather than sending a separate aperture list for a single layer. In the same token, it’s not compulsory that an aperture is sent in the 247X format files. However, if you use this format, please use a combination of your aperture list and the Gerber Files in the creation of your artwork.

To solve the problem of a missing aperture list in Printed Circuit Board manufacturing, ensure that you provide the following specifications:

  • A single comprehensive aperture list for all the layers
  • Use English Units throughout your list
  • Avoid modification of the aperture list that your software outputs.
  • An aperture list does not have to be send with the 247X format files.
  • Use extensions like .apr., and .apt. for the aperture list.

If you have problems with your aperture file such that adhering to the above specifications which lead to problems in your Gerber Files, please do not hesitate to contact us at and get professional advice from one of our experts. We can also design an aperture list and the entire Gerber File for you at a very fair price.

Missing Tool Lists

Tool lists are used in combination with Excellon drill files to create the drill. The drill file specifies the exact location of the holes whereas specifies what tool should be used in the respective position. Tool lists should always be embedded in the Excellon Drill Files or sent independently. However, we do not recommend the use of the tool list provided on the fabrication’s drawing since it eliminates most of the automatic verifications thus causing high chances of errors in the data entry procedure. Comparatively, the tool list should be comprehensive and should contain the list of all the tools that will be used in the design of the Printed Circuit Board.

To eradicate the problem of a missing tool list, it is paramount to ensure that the tool list (embedded in the Excellon Drill File) is sent as an independent text file. However, if the layout software outputs and Excellon Drill file, it should output a tool list as well. Please ensure that you use most of the common tool list extensions like .rep. and .tol. As always, if you have any coming up with your tool list, please do not hesitate to contact us at and our team of experts will be glad to work with you.

Insufficient size of Annular Ring

An annular ring is the radius of the donut (the ‘annulus’) which is formed when a drill pierces a layer of copper.  The annular ring should be designed in a way that it allows complete plating on component holes and via and the solderability on the component holes. It is, therefore, recommended that you ensure that you provide the required annular ring specifications.

A minimum of 0.005 inches annular ring should be used for vias and for component holes, a minimum of 0.007 inches should be used in the manufacturing of Printed Circuit Boards. Equally important, setting a sufficient annular ring in the layout software is more preferred so as to maintain proper spacing of copper.

Composite layers

Some PCB design softwares use composite layers in the creation of many layers. An example of such a situation is when a plane layer with embedded traces uses 3 layers to create a single layer. Some of these layers are negative images whereas others are positive images. These images should be combined and output as one Gerber layer to avoid problems in the Gerber File.

Inner clearances’ insufficiency

The inner clearance of a PCB is the minimum distance from a hole’s edge to an adjacent and unconnected inner layer copper. Maintaining sufficient inner clearances helps in ensuring that the drill doesn’t cause any shorts in the copper inner layers. It is significant that both non-plated and plated holes are cut into adjacent traces during the assembling process.

To prevent the problems caused by insufficient inner clearances on Gerber Files, we recommend that you use a minimum of 0.01 to 0.015 inches inner clearance. Moreover, modified negative image inners should be provided.

The clearance in your software is most recommended as it maintains the intended connectivity. Moreover, the affected copper traces can be moved to outer copper where they have fewer effects.Sequentially, even though most of the layout packages provide clearances as a DFM check, it is not every software that can do so. As a result, for those that cannot be manipulated, this violation should be checked by setting a higher value of annular ring and spacing as well.

If the above Gerber File problems or a new problem arises in the process of manufacturing your PCB and a permanent solution is not found, please contact us at RUSHPCB and enquire from one of our experts. Moreover, since we are one of the best PCB manufacturers, assemblers, designers and fabricators in the world, we provide any PCB or related services and a very fair price. Please visit us today and place your quote in our site.