Issue link: https://iconnect007.uberflip.com/i/1475604
64 DESIGN007 MAGAZINE I AUGUST 2022 Have you ever sat in an overcrowded meet- ing room? For me, this is never fun. I think of elbows knocking against others and poor ven- tilation. My performance degrades when I'm overcrowded. Conversely, when I sit in meet- ings within oversized conference hall rooms containing too much empty volume, I feel uncomfortable. I can't help being distracted by the hollow, reverberating sounds as well as thinking about the costs and waste of resources. To engage effectively, I need to be closer to my fellow attendees and the presenter. PCB Design Agoraphobia Just as I tend to exhibit discomfort in over- sized conference halls and meeting rooms, I self-diagnose as agoraphobic when it comes to entering PCB layouts full of wasted space. Mechanical constraints which utilize the printed circuit board substrate material as a mechanical or structural "filler" within an electronic product, under-utilizing the mate- rial for its intended purpose to support con- Practical Packaging Density in PCB Design ductive circuitry, grate on me like nails on a chalkboard. I've seen an eight-inch, triangular shaped support bracket designed out of 0.093" thick FR-4 laminate material. It was contrived and specified by an uninformed mechanical engineering overachiever who proposed trans- forming the original sheet metal bracket into a "dual purpose" PCB solution in order to sup- port the electronic engineer's connector and associated circuitry. e circuit added to this clumsy "printed circuit bracket" monstros- ity occupied just over a single square inch and seemed a ghastly waste of resources. I've lived through other well-intentioned mechanical engineering efforts to cut assembly costs—without scratching off my skin. Once, an uninformed mechanical engineer proposed a PCB to reduce assembly costs by eliminat- ing connector harnessing between multi-sec- tioned PCB assembly sets. It did not go well. It involved creating a single piece LED board which could be installed quickly into a machine using only six fasteners—a novel requirement but without consideration of all the materials and processes associated with the design for bare board manufactur- ability. Each single 19-inch diameter board ring—dubbed "the panel burner"—wasted an entire, oversized panel of copper-clad FR-4 material. e board could only be pro- cessed by a custom supplier at the time. Target Condition Feature Column by Kelly Dack, CIT, CID+ Figure 1: 3D pic of empty boardscape.