Issue link: https://iconnect007.uberflip.com/i/1114420
MAY 2019 I DESIGN007 MAGAZINE 65 Leave Plenty of Breadcrumbs for Your Fabricator As I said, we can't read your mind. Fabrica- tor notes can make the difference between a quick turn and a protracted delay. If filenames are just a jumble of numbers or we have ques- tions about what services you want us to per- form, the notes are where we can go for guid- ance. Consider the following questions: • Will the fabrication notes conflict with your order form? • Do notes call for unnecessary services? • Do you reference documents that we do not have access to? • Does the design service you selected include a technician checking your notes? Not all quick-turn prototyping services of- fer human intervention. So, if you're relying on a technician for review of your design files ahead of the quote and production process, be sure to choose a service level that includes it. Finally, and this may seem obvious, make sure you are sending your fabricator the cor- rect file. You would be surprised how often we receive the wrong files and discover it after production of the PCBs is complete. So, please invest a few minutes in your de- sign and check your Gerber files before you hit send. We want to help your rush job and keep your boss from tapping their fingers impatient- ly on your desk. DESIGN007 Bob Tise is an engineer at Sunstone Circuits. To read past columns or contact, click here. • Copper/copper • Drill/drill • Drill/copper • Pad/pad Look at Each Layer This is really the only way to visually con- firm each is correct. And by doing so, you ac- celerate the quote process and avoid cost over- runs during the production of the boards. Be- fore submitting your quote request, consider: • Does each layer import at the correct scale and size? • Are the number of copper layers correct? • Are the silkscreen and solder mask layer counts accurate? • Did the drill file read as intended, as a single file or multiple files? If not, why? • Was the drill file updated at the same time as Gerber files? • Do drill holes line up with artwork? • Were all area fills refreshed just prior to generating Gerber files? • Did you intend to have potentially expensive blind vias or buried vias? • Even one misstep in this category can create problems down the road. Though the list may seem long, the potential return on investment of a few minutes can be significant. Check Solder Mask Layers When you are double-checking each board layer, pay careful attention to solder mask lay- ers. Oversights here cannot only cause delays but result in boards that do not function prop- erly or at all. Ask yourself: • Do all pins have mask openings? • Vias under components should not have mask openings. Do they? • Are solder mask openings slightly larger— at least 0.004"—than component pads? • Are plated through-hole pads 0.015" larger than the drill, and therefore, large enough to avoid breakout? Not all quick-turn prototyping services offer human intervention.