Issue link: https://iconnect007.uberflip.com/i/1500943
20 DESIGN007 MAGAZINE I JUNE 2023 ical parameters to better correlate actual per- formance to the expected performance. What issue should PCB designers be more aware of? O v e r - s p e c i f i c a t i o n . S i g n i f i c a n t c o s t i s incurred by overspecifying requirements. One of the most c o m m o n r e a - sons for this is t h a t r e q u i r e - ment s get co p - ied from one design to another design with- o u t t h e d e s i g n e r ' s full understanding of whether they are appli- cable. Another reason is that PCB hardware engineers and designers are not sufficiently taught about cost impacts early in their career. For instance, how many PCB fabrication classes are taught at trade schools, community colleges, and four-year universities? Every day I listen to my Apple iPod that is 20 years old. It is a consumer product and probably wasn't designed or expected to last this long. I wonder how much cost was specified into the PCB that wasn't required for a board that only needed to last five or so years? How much revenue has been lost because I haven't needed to replace it? One common example of over-specification is the lack of use of IPC Class 1 requirements. ese were intended to provide sufficient mar- gin for the system to operate with a short life- time. But most non-Class 3 designers specify the PCB to be Class 2 by default. Decreas- ing the Class from 2 to 1 has the potential to increase the production yield, reduce process- ing cost, and reduce material cost, thus reduc- ing the product cost. What problem should PCB designers be more aware of? Documentation package quality. Designers who send their data to fabricators and assem- blers with Gerber-based packages require the manufacturer to manually interpret the draw- ings and specifications and manually associ- ate and enter the requirements into their CAM systems. For example, a separate netlist is required because it is assumed that the data may be wrong. Trace thickness is also manually entered. e industry has had intelligent data formats available for approxi- mately 25 years. e for- mat s are the Siemens ODB++ and IPC-2581 formats. It has been shown that less than 25% of all data packages are based on these formats. These are intelli- gent data formats that transfer the intelligent data from the CAD systems to the CAM systems such that they can automatically load a significant amount of the data with- out human intervention. ese intelligent formats also don't require as many ePaper documents, such as a fabrication drawing, bill of materials spreadsheet, stackup drawing, etc. ere are oen discrepancies between supplied documentation duplicate informa- tion that is sent. is extends the produc- tion or prototype cycle time and introduces errors. Designers should immediately work with their suppliers and switch to IPC-2581 or ODB++ to immediately reduce their design cycle time and improve data transfer quality. I wonder how much cost was specified into the PCB that wasn't required for a board that only needed to last five or so years?