Common problems in PCB design(6)

                                                   Common problems in PCB design (6)

       Surface mount device pad too short

       This is for on-off testing, for overcompact surface mount devices, where the distance between the two feet is fairly small, the pad is fairly thin, the mounting test pin must be staggered up and down (left and right), such as the pad is designed too short, Although does not affect the device installation, but will cause the test needle not to open the wrong position.

        Large mesh spacing is too small

        The edges between the same lines are too small (less than 0.3 mm). In the PCB manufacturing process, many broken films are easily formed after the screen is shown, resulting in broken lines.

        Large area copper foil is too close to the outer frame

        The distance between large area copper foil and outer frame should be at least 0.2 mm, because when milling to copper foil, it is easy to cause the copper foil to be raised and the flux shedding caused by it.

        Unclear design of outline border

        Some customers have designed contour lines in Keep layerboard, Top over layer and so on, and these lines do not coincide, which makes it difficult for PCB manufacturers to decide which contour line to use.

         Graphic design inhomogeneity

         During the graphic electroplating, the coating is not uniform and the quality is affected.

          Abnormal hole too short

          The length / width of the special-shaped hole should be ≥ 2: 1, and the width should be more than 1.0 mm. Otherwise, the drilling machine is easy to break the drilling hole when machining the irregular hole, resulting in difficulties in machining and increasing the cost.