Issue link: https://iconnect007.uberflip.com/i/1512857
44 DESIGN007 MAGAZINE I DECEMBER 2023 4 Add a simple note to specify outline pro- file to be inspected within 0.XXX" of design data. PCB designers and their project stakeholders can benefit from a simple tech- nique which draws from the GDT concept of "profile of a surface." Using this technique helps eliminate countless dimensions from the fabrication print. All that is required is that the PCB designer determine an acceptable range of tolerance. Ask yourself, "If this board edge shrinks or grows by a certain amount, what are the effects?" e tolerance zone created by a profile callout automatically applies to the zone around the PCB profile regardless of its complex shape. Take a hint from Batman: "Zap" these four steps into your design workflow. Your PCB will "zing" through the manufacturing and inspec- tion phases. Your PCB stakeholder counter- parts will love you and your PCB edges sus- pended in air will be none the worse until you go back and ask that mechanical engineer why you can't lop off Batman's pointy ear so you can fit another image on the manufacturing panel. DESIGN007 Kelly Dack, CIT, CID+, provides DFX-centered PCB design and manufacturing liaison exper- tise for an EMS provider in the Pacific Northwest while also serving as an IPC design cer- tification instructor (CID) for EPTAC. To read past columns, click here. by Bill Hargin, Z-zero Chapter 7: Rigid-Flex Materials For most of my career, I worked exclu- sively with rigid PCBs. Rigid-flex boards were those things in my cellphone. Then, about six years ago, while working in the laminate space, I started getting requests for low-flow prepregs and getting pulled into rheology testing. Since then, I have learned a lot more about rigid-flex stack- ups and included rigid-flex support in our stackup-software solution. This chapter shares some of the lessons I learned along the way. Flex and rigid-flex designs refer to a PCB that is partially or entirely constructed using dynamic, flexible substrates instead of being exclusively made of rigid substrates. Flexible materials allow for denser designs because components and traces can be placed and routed in three dimensions, eliminating physical con- nectors. This reduces cost and imped- ance discontinuities while increasing reliability. Rigid-flex designs also have improved electromechanical functional- ity, including dynamic bending, vibration and shock tolerance, heat resistance, and weight reduction. Their increased shock and vibration tolerance makes flexible designs popu- lar within medical, automotive, military, and aerospace applications that neces- sitate dependable field operation. The ability to bend portions of the circuitry facilitates dense con- structions, leading to widespread use in flat panel displays and cellular devices, while also making wearable technology possible. Continue reading... BOOK EXCERPT The Printed Circuit Designer's Guide to... Stackups—The Design within the Design Figure 4: Board edge profile shall conform to supplied Gerber data within 0.XXX" (0.XX mm).