1. Standard components should pay attention to the size tolerance of different manufacturers’ components, non-standard components must be designed in accordance with the actual size of the components pad graphics and pad spacing.
2. The design of high-reliability circuit should be widened solder plate processing, pad width = 1.1 to 1.2 times the width of the components solder end.
3. High-density design to the software library of components to correct the pad size.
4. The distance between various components, wires, test points, through-hole, pads and wire connections, solder resistance, etc. should be designed in accordance with different processes.
5. Consider the reworkability.
6. Consider heat dissipation, high frequency, anti-electromagnetic interference and other issues.
7. the placement of components and direction should be designed in accordance with the requirements of the reflow or wave soldering process. For example, when using reflow soldering process, the layout direction of the components to consider the direction of the PCB into the reflow oven. When using wave soldering machine, machine surface can not be placed PLCC, FP, connectors and large SOIC components; in order to reduce the wave shadow effect, improve the quality of welding, the layout of various components and the location of special requirements; wave soldering pad graphics design, rectangular components, SOT, SOP components pad length should be extended to deal with the two outermost SOP Wider pairs of solder pads to adsorb excess solder, less than 3.2mm × 1.6mm rectangular components, can be chamfered at both ends of the pad 45 ° processing, and so on.
8. Printed circuit board design also consider the equipment. Different mounting machine mechanical structure, alignment, printed circuit board transmission are different, so the positioning of the printed circuit board hole location, benchmark mark (Mark) graphics and location, printed circuit board edge shape, as well as the printed circuit board edge near the location of components can not be placed have different requirements. If the wave soldering process is used, it is also necessary to consider the process edge of the printed circuit board transmission chain needs to be left.
9. But also consider the corresponding design documents.
10. to reduce production costs under the premise of ensuring reliability.
11. the same printed circuit board design, the use of units must be consistent.
12. Double-sided assembly and single-sided assembly of printed circuit board design requirements are the same
13. But also consider the corresponding design documents.
Post time: Mar-10-2022