Precautions for PCB puzzle
Under normal circumstances, PCB production will carry out so-called panelization operations, the purpose is to increase the production efficiency of the SMT production line, then what details should be paid attention to in the PCB panelization? Let's take a look together below.
1. The outer frame (clamping side) of the PCB panel should adopt a closed loop design to ensure that the PCB panel will not be deformed after being fixed on the fixture;
2. The shape of the PCB board is as close as possible to the square. It is recommended to use 2×2, 3×3, ……, but not to form a Yin-Yang board;
3. PCB panel width ≤260mm (SIEMENS line) or ≤300mm (FUJI line); if automatic dispensing is required, PCB panel width×length ≤125mm×180mm;
4. Each small board in the PCB jigsaw must have at least three positioning holes, 3≤aperture ≤6 mm, and no wiring or patching within 1mm of the edge positioning hole;
5. The center distance between the small plates is controlled between 75mm～145mm;
6. When setting the reference positioning point, usually leave a non-resistance area 1.5mm larger than it around the positioning point;
7. There should be no large devices or protruding devices near the connection point between the outer frame of the jigsaw and the inner small board, and the small board and the small board, and there should be more than 0.5mm space between the components and the edge of the PCB. To ensure the normal operation of the cutting tool;
8. Four positioning holes are made in the four corners of the frame of the jigsaw, with a diameter of 4mm±0.01mm; the strength of the holes should be moderate to ensure that they will not break during the upper and lower boards; the precision of the hole diameter and position should be high, and the hole wall should be smooth and free of burrs. ；
9. The reference symbols used for the positioning of the entire PCB and the positioning of fine-pitch devices. In principle, the QFP with a pitch less than 0.65mm should be set at its diagonal position; the positioning reference symbols used for the imposition PCB daughter board should be paired Used, arranged at the opposite corner of the positioning element;
10. Large components should have positioning posts or positioning holes, such as I/0 interface, microphone, battery interface, micro switch, earphone interface, motor, etc.