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30 DESIGN007 MAGAZINE I MARCH 2024 how they are produced. At a high level, these are the steps associated with PCB manufactur- ing: • e manufacturer receives a design, and the computer-aided manufacturing (CAM) tooling department translates it into information usable during each step in the manufacturing process. is is where potential production issues are identified and corrected. • Digital design files are transferred onto a physical copper-clad manufacturing panel, oen using a high-intensity UV light source and a light-sensitive polymer (pho- toresist). e panel is the Rosetta Stone for production: defining traces, pads, and through-holes. • Next, copper is added to through-holes and external circuitry, increasing the thick- ness and ensuring the electrical connec- tion of layers and components. • e photoresist and the exposed and unnecessary copper which lies underneath it are removed. • e etching process then reveals the final printed board layout and makes it easier to visualize the finished board. • Solder mask is applied to protect most of the board from oxidation, define solder- able components, and prevent solder- bridging between them during assembly. • e silkscreen, also called the legend or nomenclature, is applied. is is the pro- cess of printing specified labels, markers, and part reference designators onto the board that helps with component orien- tation, placement, and polarity during assembly. • Surface finish is added to the remaining exposed copper, bringing the board much closer to its finished form. • Finally, the PCBs are removed from the manufacturing panel, prepped for final inspection, and then prepared for ship- ment. I encourage designers to tour the facilities where their boards are produced to get a bet- ter sense of how these processes are completed by manufacturers. For a deeper dive into the PCB manufacturing process, please refer to my book Designing for Reality. Choosing the Right CAD Tools Every profession has its tools, and the design phase begins by choosing one. Carpenters use hammer s, doctor s have scalpels, and tarot card readers draw from a deck of 78. For PCB designers, the tool of the trade is CAD soware. e market offers a wide range of PCB design soware options and choosing which to use can become overwhelming. Your budget will likely influence your decision. CAD tools range from simple and free to complex and expensive to everything in between: • ere are many low-cost and free CAD tools available but be sure such tools are still being actively maintained and provide user support. • Some low-cost and free CAD tools are funded and developed by PCB manufac- turers. ey produce tools that specifically work with their manufacturing process, which can be great if a designer has a spe- cific manufacturer in mind for their design. • ere are also CAD tools available that charge a monthly subscription price. Most offer prices that range from about $75 all the way up to over $2,000. Pay attention to the limits placed on products with mul- tiple tiers of pricing when choosing this option. Regardless of budget requirements, design- ers should focus on soware providers that are best able to support the transition from design to manufacture. Look for design tools that will: • Automate most or all of the prototype quote and ordering process