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44 The PCB Design Magazine • September 2014 IPC-2581 Advances I am a strong advocate of the IPC-2581B unified file format, because it will simplify the transfer of PCB designs from CAD tools to board manufacturers, incorporate rich attributes that help thoroughly explain exactly what designers intend manufacturers to build, and ease stackup development. The standard aggre- gates all the elements of a de- sign, every aspect from the stackup to assembly opera- tions, in a single common format for transmission from the CAD platform to the manufacturer. In my November 2013 column in The PCB De- sign Magazine, I described what my company experi- enced as the manufacturer of a test vehicle, a 12-layer network line card designed by Fujitsu Network Com- munications, which was sent to us as an IPC-2581A file (version A preceded the current version of the standard). We traced some minor anomalies to evalu- ation software supplied by our CAM vendor, which I un- derstand have been corrected, but we proved the integrity of the IPC-2581A de- sign file. Under the auspices of the IPC-2581 Consortium, which now numbers 60 member companies (see www.ipc2581.com), there have since been major enhancements to the standard and there is work underway to explore how it could integrate other elements to augment con- ventional PCB description and manufacture, such as device firmware. The most significant new provision in the B version, from my vantage point as a manu- facturer, is the ability to develop a stackup in- teractively with a designer. Gary Carter, one of the consortium founders and senior manager for CAD engineering at Fujitsu Network Com- munications, put this in perspective during a recent conversation. "Material stackup is now supported in RevB. That's a big win in the early part of design, when designers spend a lot of time talking with their fabricator about the choice of materials to meet the design requirements they specified," Carter explained. "Today, it's the passing of napkins, telephone calls, and maybe at the end of the day a JPEG or PDF file from the fabricator fol- lowing the dialog. Then they [the designers] have to hand-enter the particulars back into their CAD system." Carter continued, "With RevB, we've dem- onstrated the capability to move information from a CAD system into a SI tool that has some knowledge of materials and from there, back over to a fab- ricator, who can respond with suggestions. We can then go back into the same tool and verify that the at- tributes of the suggested materials do in fact yield the correct results, and then [seamlessly] go back into the CAD system to fi- nalize the stackup, and off we go." There is no paper involved, and the bidirectional exchanges be- tween the designer and the manufacturer dur- ing the stackup development take place via the CAD tool that will render the design. The ability to develop and communicate design in- formation in a consistent format in the same electronic medium from the very inception of a project at the stackup stage all the way through to the CAM equipment used for production en- sures that no detail will be misplaced or misin- terpreted. This is indeed a big win. PCBDESIGN design for manufacturing Amit Bahl directs sales and marketing at Sierra Circuits, a PCB manufacturer in Sunnyvale, California. He can be reached by clicking here. Material stackup is now supported in RevB. That's a big win in the early part of design, when designers spend a lot of time talking with their fabricator about the choice of materials to meet the design requirements they specified. " " IPC-2581B EASES STACKUP DEVELOPMENT continues