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34 The PCB Design Magazine • September 2017 For years, DFM for flexible and rigid-flex cir- cuits has been ignored. However, as nearly 30% of all electronics companies have flex and rigid- flex circuits within their product portfolios, the segment merits attention. And, with more com- panies moving to flexible electronics, this trend and this segment's DFM needs will only con- tinue to accelerate. The materials and manufac- turing processes are quite different for flex and rigid-flex circuits, and the DFM tools must sup- port those needs. Being able to identify features within a bend area are critical, as is maintaining sufficient clearance around a coverlay zone, for example. Performing DFM analysis concurrent with the PCB design process increases the competi- tive advantage. But, to make this practical, the DFM software needs to be well-integrated with the EDA software so that the designer can run the analysis and review the results for ba- sic DFM within the environment of the layout tools. By doing so, they avoid having some- one downstream telling them there is an issue. Downstream is no longer adequate. Upstream is required to compete today. As evidence that the electronics industry has evolved beyond just DFM, NPI software is also used to design and optimize PCB panels. Many companies are inefficient in their pan- el-design process, even for assembly panels or arrays. Typically, a design organization will use a 2D mechanical CAD tool to create a drawing of what they need for their assembly panels to look like when received from the bareboard fab- ricator. They will spend an hour or more creat- ing this drawing and adding notes and dimen- sions, then they output it to their fabricator as a dumb drawing file. By "dumb," I mean the drawing file has no intelligence to it, no data that the fabricator can key off of in the tooling process. Rather, the fab engineers must recreate the assembly array within their CAM software and submit a proof image back to the designer at the OEM for ap- proval before proceeding with tooling. Needless to say, with good technology, this level of man- ual processes isn't necessary today. Instead, the same design organization can easily create their assembly panels using the NPI software and include all the elements needed— rails, tooling holes, fiducials, and rout or v-score features. Good NPI software will even automati- cally optimize the boards within the assem- bly panel to minimize the fabrication material costs. When trying to drive down the costs of electronic products, reducing fabrication mate- rial costs is often an overlooked opportunity. In a study we conducted with four different customer designs, we found panel optimization saved an average of $126,450 annually per cus- tomer, and these savings could be had with as few as four panels. Furthermore, DFM analysis done on the assembly array will identify poten- tial manufacturing issues not able to be identi- fied in the single-up stage. A couple of good ex- amples are having a breakaway tab too close to a SMD pad or a device that overhangs the edge of the PCB obstructing machine vision access to a global fiducial. Lastly, the NPI process involves creation, validation, and delivery of the design package to the fabrication and assembly providers. His- torically, it's delivered as a package comprised of some combination of the following: • Gerber files • Drill files • Netlist files • Test files • Centroid data • Manufacturing BOM • Drill drawings • Assembly panel drawings • Route drawings • Stackup drawing • Drawing notes For an industry that drives the digitalization of the world, we sure are heavily dependent on manual processes with instructions communi- cated through 2D, non-relational drawings and documents. What is in the drawing or documen- tation that cannot be represented as a data field (Figure 3)? Nets that are intentionally shorted? Data field tagged to the appropriate nets. Top- side soldermask color? Data field. Dielectric thickness for a given material? Data field. Dimensions are an interesting topic for digi- talization. An electronic product model theoret- ically does not required a dimensioned drawing. IT'S NOT YOUR FATHER'S DFM ANYMORE