Issue link: https://iconnect007.uberflip.com/i/1464168
52 DESIGN007 MAGAZINE I APRIL 2022 As noted in the introduction, the goal for addi- tive manufacturing is to achieve the same opti- mizations, ensuring a continuous digital thread so that there is absolutely no redesign as the design passes through various design and veri- fication tools and on through to manufacturing (Figure1). Part of the challenge today is that there are so many manufacturing technologies and materials in research that it's hard to focus on optimizing a moving target. At first glance, the process chart in Figure 1 could easily represent traditional PCB flows, but a closer look reveals many new challenges: • e delineation between ECAD and MCAD is blurring so much that electro- mechanical design may have to be done in one tool. • Design constraints will have to consider the variability of the materials used. • Given the operating conditions of these new structures, a host of multi-physics analysis will be required to ensure performance (e.g., signal, power, thermal, EMI, stress, vibration, stretch, moisture, impact, deformation, and manufacturability). • e product model transferred to manu- facturing will need to maintain design intent to eliminate redesign. Planar electronics could leverage existing PCB models (e.g., ODB++, IPC-2581), but today many of the tools in additive manufacturing don't accept them. Non-planar electronics will likely require a completely new model. In both cases, the path from design may flow through MCAD, rather than the traditional ECAD outputs. • In manufacturing, the process prepara- tion stage must apply to multi-material "slicing" and "tool-pathing" algorithms to ensure that the structure is printed as designed. be flexed or molded into the final form. Advanced technologies that fit the planar design model today include flexible hybrid electronics (everything's flexible, includ- ing the ICs and batteries), molded inter- connects, and 3D conformal "wraps" (e.g., 2D designs converted to fit a 3D structure, then printed). PCB design tool advances made over the years to support rigid-flex, localized dielec- trics, HDI, wire bonding, and embedded actives/passives can aid in the design of pla- nar structures (i.e., make the digital twin more intelligent, rather than creating work- arounds that must be explained or converted for manufactur ing ). Cer tainly, design for manufacturability takes on new meaning when you must ensure things like intercon- nect and impedance continuity in the final flexed/conformal structure. In this design chain, MCAD tools become more critical, but there's still the physical separation between electronics and associated mechanical enclo- sures or mounts. Non-planar electronics can have intercon- nects and components placed at any angle, in any location in a given space. ere's no func- tional reason to separate electronics from a mechanical enclosure. ey're one and the same—the ultimate in electro-mechanical structures. Given the geometrical challenges, current prototypes of these structures are oen designed in MCAD as non-electrically intelligent structures, forgoing much of the automation and verification technologies built up over decades in ECAD. ese structures are still relatively simple, so the trade-off is accept- able, but as complexity increases, the need to maintain electrical intelligence and model per- formance will increase. Optimizing the Tool Chain Over the last 50-plus years of PCB design and manufacturing, the tool chain from design through manufacturing has become fairly opti- mized (there are still areas for improvement).