Double-sided multi-layer PCB circuit board assembly rules and techniques

1. PCB panel width ≤ 260mm (SIEMENS line) or ≤ 300mm (FUJI line); if automatic dispensing is required, PCB panel width × length ≤ 125 mm × 180 mm. 

2. The PCB panel shape should be as close to the conventional graphics as possible. It is recommended to use 2*5 or 3*3 panels. The panels can be assembled according to the thickness of the board;

3. The outer frame of the PCB panel should adopt a closed-loop design to ensure that the panel will not deform when fixed on the fixture.

4. The center distance between small plates is controlled between 75 mm and 145 mm.

5. There should be no large components next to the connection points between the panel shape and the small boards inside the PCB, or between small boards, and there should be a space of more than 0.5mm between the components and the edges of the board.

6. Drill four positioning holes in the four corners of the outer frame of the puzzle, add Mark points, and have a hole diameter of 4mm (±0.01mm); the strength of the holes should be moderate to ensure that they will not break during the loading and unloading process, and the hole walls should be smooth and burr-free. 

7. In principle, QFPs with spacing less than 0.65mm should be set at their diagonal positions; the positioning reference symbols used for imposition of PCB sub-boards should be used in pairs and arranged at the diagonal corners of the positioning elements.

8. When setting up the reference positioning point, usually leave a non-resistive welding area 1.5 mm larger than that around the positioning point.

9, for some large components to leave a positioning column or positioning holes, focusing on such as I / O interface, microphone, battery interface, microswitch, headset interface, etc.