Why Your Team Should Consider IPC-2581 for Production Data

Ask any manufacturer, and they will tell you: just about every manufacturing deliverable package that comes into a modern facility will have something wrong with the production data. This is a well-known problem and attempts have been made to improve the set of outputs provided by designers so that all the data is consistent. The problem is multi-faceted, but one aspect that designers can control is the output file formats.

Due to the number of files required in a Gerber export, and the possibility that these files are mismatched with other deliverables, there is always the possibility that production data are inconsistent across the entire production file set. So what can be done about it? The IPC-2581 standard aims to change this by reducing the overall set of deliverables to a single file. If your company has not started using this more advanced format, here’s why you should start.

Reduce Your File Burden With IPC-2581

Currently, there are three major deliverable formats used to provide PCB manufacturers with the data they need to fabricate a bare printed circuit board. These are:

• Gerbers (RS-274-X and X2 formats)
• ODB++
• IPC-2581

Manufacturers overwhelmingly support the Gerber format as an entry-level file format for PCB fabrication. The format is something of a de facto standard; it is primarily used by a manufacturer because all other manufacturers and designers continue to use it. This is despite known problems with the workflow surrounding the use of this file format.

How Big Are Gerber-Based Databases?

The main issue surrounding Gerbers is the sheer number of files required to describe the set of layers in a PCB. The table below compares the number of different files required to describe a PCB for fabrication and assembly across the three major formats.

It should be quite clear that the IPC-2581 standard reduces the number of files needed to transfer PCB data into fabrication.

What’s The Problem With Gerbers/ODB++?

What’s the matter with using Gerbers or a large ODB++ archive? There are several problems that can arise.

One of the biggest problems with the Gerber standard is inconsistent data across files. For example, master fabrication/assembly drawings may have different information than drawing layers embedded in a PCB mechanical layer. There may also be inconsistent data in the BOM compared to the rest of the design, which can arise when supply chain teams start modifying the BOM manually. Currently, there is no mechanism for enforcing consistency across these files and the PCB layout data based on the definitions in the Gerber file format.

ODB++ solves some of these problems by embedding much of the information into the ZIP archive. With some viewers, it is possible to spit out BOM and assembly information. The main advantage of ODB++ is the embedding of net name information and layer information into the data archive, which helps with NRE processes in CAM software.

ODB++ review before fabrication.

What Will it Take to Switch?

IPC-2581 has two big advantages compared to Gerbers and ODB++: reduction in the number of files required for production, and the embedding of all the required data into a single file. With a single file, an entire design can be represented and used to create tooling for PCB fabrication. The same file is used for extracting a BOM and planning PCB assembly.

The drawbacks of Gerbers have been known for a significant amount of time, and the reasons people have still not switched are still unclear. There are likely several reasons that designers have not made the switch to using IPC-2581 as the primary deliverable format for their projects. Some of these could include:

• Manufacturers continue to demand Gerbers for quoting
• Designers continue to send Gerbers to fabricators for quoting
• There are many free viewers and editors for Gerbers
• Gerbers readily convert to DXF files
• IPC-2581 does not easily convert to Gerbers except with paid software
• Companies are not demanding their customers or vendors use IPC-2581

We can only speculate as to why there has not been a greater movement to make use of the IPC-2581 standard by manufacturers or designers. No matter what output format you or your customers demand, the best commercial CAD tools support all three output format standards with easy export options and workflows.

IPC-2581 export from Cadence OrCAD

No matter which manufacturing file formats you need to export, you can create a complete design and production database with the PCB design tools in Allegro PCB Designer. Allegro is the industry’s best PCB design and analysis software from Cadence, offering a range of product design features with a complete set of management and version control capabilities. Allegro users can access a complete set of schematic capture features, mixed-signal simulations in PSpice, and powerful CAD features, and much more.

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