Different Manufacturing Processes of PCB Pad 1
What are the effects and requirements of different PCB manufacturing processes on the pads? In this article, EPCB summarizes some guidelines for your reference.
1.The test components must be added at the two ends of the SMD component which is not connect other components. The diameter of the test point should be between 1.0mm~1.5mm to facilitate the test by the in-circuit tester. The pad edge of the test pad is at least 0.4 mm from the edge of the surrounding pad.
The diameter of the test pad which has network properties is more than 1mm. The center distance between two test pads should be greater than or equal to 2.54mm. If the via is used as a measurement point, a pad the diameter above 1mm must be added outside the via hole.
2.Holes with electrical connections must have pads. All pads must have network properties and different network names. The distance between the center of the positioning hole and the center of the test pad is more than 3mm.
Other irregular shapes but with electrically connected slots, pads, etc., are placed on the mechanical layer 1 (slotted holes such as single inserts, fuses, etc.).
3.Component pads (eg, ICs, swing sockets, etc.) with tight pin space (less than 2.0mm) must be added to the test pads if they are not connected to the hand pads. The diameter of the test point should be between 1.2mm~1.5mm so as to facilitate the test.
4.If the distance between the pads is less than 0.4mm, white oil must be spread to reduce the overspread.
5. If there is a hand-soldered component on a single board, the tin path must be fabricated. The direction is opposite to that of the tin. The width is decided by the hole size.
6.Conductive rubber button spacing and size should be consistent with the actual size of the conductive rubber keys, PCB board connected to this should be made as a gold finger, and the provisions of the corresponding gold-plated thickness is generally greater than 0.05um ~ 0.015um.
7.The pad size and spacing should match the size of the SMD component.
a.If no special requirement, the shape of the hole and pad should match the shape of the component pins, and the symmetry of the pad relative to the hole center must be ensured;
b.Adjacent component pins or pin-compatible devices in the same circuit should have separate pad holes, especially the compatible pads of the package-compatible relay. If PCB layout cannot set a separate pad hole, the two pads must be surrounded by the solder mask.
To be continued…