“Put ‘em down! Pick ‘em up! Put ‘em down! … Pick ‘em up!” was how my fellow enlistees and I were greeted upon arriving for basic training after traveling for most of the day. These loud commands continued until we finally adjusted to the cadence and our bags hit the ground in unison. To help us understand the purpose of this conformity, we were also subjected to the humiliation of straggling around the base in our civilian clothes as what is sarcastically referred to as rainbows. Over the next several weeks, we become quite good at moving as a unit in perfect synchronization.
Like in a military formation, uniformity has its advantages. For example, for the efficient manufacture of your boards, a well-defined format including all PCB design essentials is preferable. Without a standard format, the process of transferring your design to your contract manufacturer (CM) can include a series of time-consuming back and forth communications that will negatively impact the turnaround time and may result in errors if the information is incomplete or misunderstood. Although Gerbers have existed as a pseudo-standard for PCB design files for the past few decades, there are inherent problems that point to the need for a better one. To address this need, a number of industry principals have joined to develop IPC-2581. However, before exploring whether this standard is a better alternative to Gerber files, let’s see if we can define a criterion for a design file standard that promotes optimal PCB design and development.
Why a PCB Design File Transfer Standard?
Before defining a set of requirements for a PCB design file format, it seems important to establish why a standard is needed in the first place. Today, electronics and PCBs are pervasive in products that span virtually all industries. This utilization will only increase as we continue to add capabilities and functionality and further automate systems that have previously been operated by humans. All of these systems rely on the ability of PCB manufacturers to create boards that structurally reflect the intent of the designer, which is best accomplished when the CM has a complete understanding of the designer’s intent.
The single instrument that conveys a designer’s intent is the PCB design file. Therefore, this file must be formatted such that it includes all design information and can be easily understood by practically any CM. This basic objective was the motivation for the adoption of the Gerber file format as the unofficial industry standard, which is currently RX-74X or X1. There is a newer version, X2, that is not as widely used. X2 was created to address the thrust by CMs to have designs generated in CAD files that are more complete, concise and typically reduce the need for extensive back-and-forth with the designer.
As PCB manufacturing equipment is software-driven, most CMs prefer a CAD file format that allows for easier integration. Gerber files, by contrast, typically require the assembly and alignment of several files, which introduces the probability of error. To promote the use of CAD files, many CMs offer PCB design software that generates the design files in their proprietary format. Although this method of development does address the data accuracy issue, it works against the standardized format requirement, which does not serve the industry as a whole. Therefore, there is still a need for a PCB design file format that fulfills certain requirements.
PCB Design File Transfer Standard Requirements
The best PCB design file format standard should possess the following attributes:
- Can be easily generated by PCB designer software
- Can be easily processed by CMs
- Is concise and accurate
Establishing a PCB design file transfer standard that satisfies these criteria will facilitate a quick quote process and efficient PCB manufacturing. Let’s see if the IPC-2581 standard is adequate for this purpose.
Why the IPC-2581 PCB Design File Transfer Standard?
One of the strengths of the Gerber file format was its graphical basis, which worked well for designers using PCB design software. However, when combining multiple image formats, a degree of error is introduced for each alignment. This was a problem for CMs and could result in several cycles of design modifications before an accurate quote could be generated. Today, most CMs offer a preferred CAD file format option. The most generic of these is IPC-2581, which incorporated ODB++ and is used throughout the industry.
In contrast to the Gerber file format, which was developed and is owned by a single company, the IPC-2581 was developed by a consortium consisting of various organizations in the PCB industry. This group consisted of both designers/developers and CMs and operated with the goal of creating a freely available PCB design file format standard that seeks to increase the efficiency of PCB manufacturing, promote innovation and minimize development costs. This effort has paid dividends. In 2012, a Fujitsu design using the IPC-2581 format was manufactured and a 30% decrease in development time was achieved. The table below contrasts the attributes of the IPC-2581 format with the most popular Gerber file version, X1.
IPC-2581 versus Gerber Files Design File Transfer
|PCB DESIGN FILE ATTRIBUTES||Gerber Files||IPC-2581|
|Format is readily available to designers||✔||✔|
|Format is readily available for CMs||✔||✔|
|Requires multiple files||✔|
|All data in a single file||✔|
|Single entity development||✔|
|Prone to errors||✔|
As indicated by the listing above, IPC-2581 compares favorably to the Gerber file format. However, even when the advantages are clear, the transition from old to new can sometimes be painstakingly slow. Nevertheless, most advanced PCB software platform developers are capable of generating both formats, which allows you to make the best choice for your design.
Tempo Automation, a corporate member of the IPC-2581 Consortium, is the industry leader in fast, high-quality agile PCB manufacturing. We utilize a number of the most common comprehensive CAD file formats to facilitate your innovation and maximize fabrication and assembly efficiency. And we will work with you, beginning on day one of design, to optimize the development of your boards.
|Tempo‘s Custom PCB Manufacturing Service|
And to help you get started on the best path, we furnish information for your DFM and enable you to easily view and download DRC files. If you’re an Altium user, you can simply add these files to your PCB design software.
If you are ready to have your design manufactured, try our quote tool to upload your CAD and BOM files. If you want more information on the IPC 2581 design file format or other design file formats, contact us.