IPC-2581 transfer standard gains momentum

Richard Goering is senior manager of technical communications at Cadence Design Systems. As an editor for Computer Design, EE Times, and SCDsource, he has been writing about EDA and IC design for 25 years.

The link between printed circuit board design and manufacturing may soon join the 21^st century as PCB design and supply chain companies test, refine, and adopt the emerging IPC-2581 data transfer standard. At the recent PCB West 2013, speakers from the IPC-2581 Consortium provided an update on a fast-moving standards effort now backed by 46 companies who have joined the consortium.

Aside from the expanded consortium membership, here’s what is new with IPC-2581 since last year’s PCB West:

• Two identical boards have been successfully fabricated by different vendors using a single IPC-2581 file
• A "Rev B" standard with many improvements was completed from start to finish in 12 months
• For the first time, individuals may join the consortium with an associate membership

Here’s some quick background. The venerable Gerber format (which goes back to the 1960s) can transfer image data to manufacturing, but it can’t transfer stackup data, materials information, design intent, or netlists. As a result, PCB designers typically ship multiple files to fabrication and assembly houses, along with documentation explaining what it all means.  

One attempt to create a more inclusive, intelligent format was ODB++ from Valor Computerized Systems, but with the 2010 acquisition of Valor by Mentor Graphics, that format came into ownership by Mentor. Thus, there is a renewed push behind IPC-2581 – originally released in 2004 but not deployed – as a vendor-neutral data exchange format that will provide a single file for fabrication, assembly, and test.

The PCB West 2013 update was provided by Hemant Shah, product marketing director at Cadence, and Gary Carter, manager of CAD engineering at Fujitsu Network Communications. "Our purpose is to provide an open standard unencumbered by any agreement you have to sign," Shah commented.

IPC-2581 consortium update

Shah opened the PCB West session with an update on the IPC-2581 Consortium, which represents systems companies in addition to providers of PCB CAD tools, design for manufacturability (DFM) software, electronic manufacturing services (EMS), fabrication, assembly, and test. The consortium has a detailed website that lists members, provides background, and explains current activities.

Last year the consortium announced the first PCB fabricated using IPC-2581. It was a 12-layer, plug-in optical module that’s in production at Fujitsu Network Communications. The board was fabricated with 30% less setup time compared to a traditional approach using the Gerber format and multiple files.  

At PCB West this year, Carter (right) showed two identical new boards that were recently fabricated using IPC-2581. The boards used Cadence Allegro software for PCB design, Wise Visual CAM software for pallet generation, and Frontline Genesis 10.2 fabrication software. One board was built by Sanmina and the other was built by Sierra Circuits.

"We were very pleased by the results," said Carter. "It really proves that IPC-2581 is rapidly proving the ability to move into production. It’s a big win for me because it is not only going to simplify fabrication, it is also going to replace the proprietary assembly output that we produce today." The next challenge, he said, is to assemble some parts on these boards using IPC-2581.

IPC-2581 RevB: quick revision

Another major accomplishment is IPC-2581 RevB, which has substantially enhanced the original 2004 standard. "We went from RevA to RevB in 12 months time," Carter said. "I’ve never seen an IPC standard move that fast."

Significant features in RevB include the following:

• Ability to define "build intent" through stack ordering, material types, technology attributes, and stackup composites
• Expanded bill of materials (BOM) section to include stackup
• Geometry object fill types, line types, user-defined primitives
• Back drilling support
• Pin one, origin/orientation standard criteria, and pick-up point for packages
• Pad stack reference definitions
• Z-axis definition, V-groove cavity/slot report
• Ability to add more notes on design intent

Shah noted that padstack information today is typically conveyed in Excel spreadsheets. Problems are not discovered until the board is in manufacturing—and by then, they are very expensive to fix. With IPC-2581 RevB, padstack information can be exported to, and imported from, PCB CAD and CAM tools. Thus, a PCB layout tool can take in a pre-layout stackup design, perform the layout, and output a final stackup design to fabrication. No data translations are required.

A final bit of news is that the IPC-2581 Consortium is now accepting memberships from individuals (until now, only companies could join). All you need to do is fill out a form at the consortium web site. Why join? You can be a "pioneer of the industry," Shah said, and network with other individuals who believe in the IPC-2581 standard. You’ll have access to the latest information and knowledge. And the price is right—it’s free.

To learn more, visit the IPC-2581 Consortium website.