Estimated reading time: 7 minutes

Design Circuit: IPC-2231A—Insights from the IPC 1-14 DFX Subcommittee

In mid-2019, IPC released IPC-2231 DFX Guidelines, a comprehensive guide for establishing best practice methodology in developing a formal DFX (design for excellence) process for laying out printed boards and assemblies. This process can be established at a systemic level—integrated into the workflow of departments of companies—or adhered to as an individual designer. DFX is multifold, and as defined by the document, includes design for manufacturing, fabrication, assembly, testability, cost, reliability, environment, and reuse. The sections pertaining to these major theme areas discuss how they impact the overall performance and cost of the final board assembly.

Of course, no document is perfect, and as is the case with nearly every industry standard, certain elements of the IPC-2231 were identified as needing to be changed shortly after its publication. Now, two years after its initial release, IPC-2231 is close to receiving an upgrade with a new revision—IPC-2231A. The standard is currently in Final Draft for Industry Review and the standard’s subcommittee is in the process of forming a ballot group. (For those who are unfamiliar with IPC standardization processes: All IPC documents are subject to a final vote for publication via an open ballot.)

While it can be dangerous to speak of the features of a document in the middle of its development cycle, it is safe to say that nearly every section of IPC-2231 has received an upgrade or addition, and an entirely new section regarding the impact of design choices on fabrication processes has been included. Speaking personally (not as a member of IPC staff), the new revision is a substantial upgrade; it’s more focused and yet more rich in content, more easily digestible, and more valuable as a resource.

But enough of what I have to say about the document. After all, other than a few minor editorial changes and tweaks, I am not the author; IPC documents are created “in the open” by industry volunteers. In fact, IPC-2231A is built from more than a century’s worth of collective experience through the participants of the IPC 1-14 DFX Subcommittee. For this column, I thought that it would be interesting to highlight some of the 1-14’s dedicated volunteers who have helped IPC-2231A come to fruition. Their insight and experience have helped to build the A Rev (and in some cases, the vanilla document) and I cannot think of better individuals to speak on its need and promise. I spoke with a few of these supporters and asked them about their involvement in IPC-2231A’s development as well as why they feel the document is needed.

Russ Steiner is a team leader in the ECAD Operations Department at CASCO Automotive, an Amphenol Company. He has been involved with the IPC 1-14 Subcommittee for the last two years. Russ manages a global team of engineering professionals who design robust products, and therefore has a critical need for a global DFX process that ensures complete compliance and integrity. When asked about the need for 2231A in industry, he responded, “Global operations and design portability is a key consideration for hedging against prospective manufacturing venue catastrophes, manufacturing redundancies, and predictable AQL/PPM.”

Others find value in how a guideline like IPC-2231A can help single employees work cohesively inside of a huge team, either as part of large companies or within manufacturing supply chains. Joe Clark of Lockheed Martin Missiles and Fire Control, PWB Fabrication and Design, has been involved with 1-14 for about a year. Referring to IPC-2231A, Joe said, “Knowledge continuity in the electronics industry is an issue at many companies since the design and manufacturing processes span many functions and roles. The IPC-2231 document helps bridge the gap in knowledge for those who may play a single part in the overall process.” Indeed, by capturing the knowledge and needs of the complex chain of requirements imposed by manufacturing, testing, and lifecycle considerations, guidelines like IPC-2231A can become the leverage that designers can use to justify design decisions. Patrick Phillips of Northrop Grumman put that more succinctly by replying that IPC-2231A contained “tools for people to use for building a case to drive product improvements.”

Others still found that the general mindset of DFX will not only help individual companies cohere their processes internally or the processes of their contractors and manufacturing verticals, but also to create some alignment between companies in general—even competitors—who all would benefit from best practices offered by a consensus document.

Pietro Vergine, president of Leading Edge, provided an excellent summary of this point: “I think that most companies are already using internally developed rules/methodologies that are DFX-oriented, but maybe call them something different (i.e., designing documents with design rules, rules for the assembly, design rules for manufacturing, or electrical design rules). As with all other IPC standards, I think that having [IPC-2231A] that has a general consensus from the electronics industries with the collaboration of several companies may have a great impact on all of their activities. It might not be perfect, but it will let us think about the global picture, and not just a single problem.”

Many found that certain sections of the document contained knowledge that is critical to help designers understand the effects of their design choices on downstream cost drivers, most notably manufacturing. Jasbir Bath has been integral in the development of the IPC-2231A, where he employed his experience as a support advisory engineer at Koki Solder to enhance its information regarding process engineering. “Manufacturing yield needs to be improved and documents such as 2231A [can] help designers understand more about the challenges in manufacturing to help design products with improved manufacturing yield,” Jasbir said, adding that he was most excited about “generally updated information on soldering materials, processing temperatures, board finishes, and reliability concerns” within IPC-2231A.

Jasbir was far from alone in feeling the need for more understanding of DFM within industry. Scott Vorhies, a primary contributor for all DFX-related information concerning the assembly of PCBAs within SpaceX, hopes that IPC-2231A will “provide a source of information helping manufacturing engineers troubleshoot assembly issues from start to finish,” noting that “this document, if allowed to be a source of truth, would greatly enhance the ability of designs to be manufactured at a lower cost and higher reliability, and help bridge the gulf between design and manufacturing.” Geok Ang Tan of DSO Laboratories agreed, and similar to Patrick’s sentiments, said that “with this, staff can share with management that there are a lot of details in the manufacturing process to produce electronics hardware; new staff will gain a lot from it.”

Jon Bruer of Creation Technologies is most excited about the design for testability (DFT) section of IPC-2231A, which he has helped shape for the new revision by channeling his more than 32 years of experience in test engineering and DFT. Regarding the need of a DFX guideline in industry, Jon said that “certainly from a test perspective there is a huge need for a stronger understanding of DFT and test requirements for production test, mostly with respect to OEM engineering teams. That said, as a contract manufacturer, my company helps to provide input and helps to fill the gaps for our customers. I think that the more awareness there is in the industry for DFT thinking to occur at the earliest stage in product design, the more testable product designs will be as they move into the production area.”

The overall outcome of IPC-2231A, according to Karen McConnell of Northrop Grumman and a current co-chair of the IPC 1-14 DFX Subcommittee, is to help companies that “do not have a DFX champion to facilitate the insertion of best practices into processes.” Moreover, she expects that the practices described in IPC-2231A should and will be rolled down to subcontractors, so that excellence can be maintained throughout the supply chain.

Regardless of which “X” in DFX is being considered, all members of the 1-14 DFX Subcommittee agree that no company is perfect, and any design process can be enhanced. IPC-2231A DFX Guidelines is expected to be available in early Q3 2021, and until then, I will leave you with one of my favorite quotes from my poll of the 1-14 Subcommittee. When asked about the importance of DFX in design, Murilo Levy Casotti of Embraer, simply replied that “[DFX is] primordial. All ‘design fors’ are very important.”

This column originally appeared in the March 2021 issue of Design007 Magazine.