Issue link: https://iconnect007.uberflip.com/i/1475604
68 DESIGN007 MAGAZINE I AUGUST 2022 Over the past few years, project stakeholders have been faced weekly with rippling pandemic effects causing severely disruptive compo- nent and material shortages. e extenuating supply chain challenges are causing perfectly performing board design layouts to require making room for substitute parts which may only be available in larger form factors or less- than-ideal packaging technologies which do not match the "qi"—the vital life force—of the PCB design. Argh! Enough on the philoso- phies already. What can be done to fix this? I've actually been incorporating a PCB design concept of my own for quite a while. I call it practical packaging density, plus (or PPDP). It's rather simple. First, packaging density for electronics has long been considered an essential measurement for determining ease or difficulty of manufac- turing, reworking, or even re-designing a prod- uct. Packaging density can have a monumental effect on electronic performance. We should strive to start our electronics product design methodology by considering all materials, manufacturing, and performance constraints from the inside out for a product, to establish a practical packaging density for our PCBs. is means that the design layout will be stake- holder friendly and priced right for all project stakeholders, including the customer, through- out its design cycle. is means a project team will have to spend a lot more time on the front end of a project researching availability, manu- facturing constraints and, most importantly, dialing design rule settings away from limited IPC class C producibility to achieve the defini- tion of practical packaging density. However, I've met too many designers who are in the habit of calling up a local PCB pro- totype shop to ask about pushing the shop's capabilities: How small holes can be drilled, how close copper images can be spaced and etched, and how tight solder mask patterns can be registered. ey ask and are typically given minimum producibility requirements. Upon receiving the values, they go right to the design constraint settings in their layout tools and enter the (minimum) values given. is philosophy is counter-productive for all. Designing to minimum manufacturing con- straint capability is like continually red lining a running motor. It's hard on the systems, which are bound to break down. e final step in the PPDP concept is to incorporate some extra space. To move toward successful packaging design, designers need to reverse thrusters by adding more space and clearance to what is already considered practi- cal. is is the plus in PPDP. It is the plus that will end up helping reduce the domino effect of component placement if your team cannot find drop-in replacements for those components which have gone EOL (end-of-life). It is the plus that will help out that tech who needs just a bit of extra clearance to rework that compo- nent. It is the plus that is very minor regarding increasing material costs but can save count- less dollars in time and effort in manufactur- ing, rework, test, and re-redesign. Regardless of our viewpoints on metaphys- ics, feng shui, or any unfamiliar cultural tradi- tions involving proximity, energy, crystals, har- monic forces, and even a little "black magic," it may be surprising for us to realize that creating a holistically successful printed circuit assem- bly already includes most all these ancient ingredients plus a little bit more. DESIGN007 Kelly Dack, CIT, CID+, provides DFx centered PCB design and manu- facturing liaison expertise for a dynamic EMS provider in the Pacific Northwest while also serving as an IPC design certification instructor (CID) for EPTAC. To read past columns, click here. Enough on the philoso- phies already. What can be done to fix this?