Design For Manufacture


SparkFun has posted an excellent guide to the many different issues you could run into when you finally decide to get a circuit board professionally produced. We assume that most of you aren’t running a professional design firm and will appreciate these tips gleaned from years of experience. They provided a rule list, Eagle DRC, and CAM file to help you get it right the first time. The end goal is designing a board that won’t be prone to manufacturing errors. The tutorial starts by covering trace width and spacing. They recommend avoiding anything less than 10mil traces with 10mil spacing. For planes, they increase the isolation to 12mil to avoid the planes pouring onto a trace. They also talk about annular rings, tenting, labeling, and generating the appropriate gerber and drill files. SparkFun isn’t completely infallible though, and manages to produce a coaster from time to time.

SparkFun naturally followed up this strict tutorial with a guide to unorthodox header hole placement. If you want to learn more about Eagle, have a look at [Ian]’s overview of Eagle 5 and Ruin & Wesen’s layout videos.

4 thoughts on “Design For Manufacture

  1. I don’t know what board house they use, but in my experience, you take the specifications provided by the manufacturer, and set your DRC rules to be equal to their limits. If they mess up, then you can contact them to fix their problem.

  2. I’ve found that when I produce boards I run them through a set of design rules I know my manufacturer will accept. I send them away and they check the design to ensure they can manufacturer it. If they find a problem with the board that I didn’t pick up they’ll pop me and email telling me what the problem is. Sometimes if it is just something small they’ll fix it for me and let me know what they’ve done.

  3. The tutorial claim: “But a plane (sometimes called a polygon plane) increases the odds of the plane being mistakenly ‘poured’ onto a trace.”
    That’s bullshit.
    The picture show a PCB which have had dirt on the PCB or on the film when being manufactured. It has nothing to do with the polygob plane.

    The limit’s they use are also totally out of date.
    Any normal PCB manufacturer accept 0.5mm track/spacing (even for polys) and 0.2mm holes without a problem, these days. And that’s without additional costs.
    If _your_ manufacturer cant, find another.
    If your boards are produced by a ultra low-cost, low quality manufacturer like Olimex, you have only yourself to blame.

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