Things to pay attention to in PCB Panel
In order to facilitate production, PCB circuit board panel generally needs to design Mark points, V-grooves, and process edges.
First, the pcb panel shape
1. The outer frame (clamping edge) of the PCB panel should adopt a closed-loop design to ensure that the PCB panel will not be deformed after it is fixed on the fixture.
2, PCB board width ≤ 260mm (SIEMENS line) or ≤ 300mm (FUJI line); if you need automatic dispensing, PCB board width × length ≤ 125 mm × 180 mm.
3, PCB layout as close to the square as possible, it is recommended to use 2 × 2, 3 × 3, ... puzzle; but do not spell into a yin and yang;
Second, V-shaped groove
1. After opening the V-groove, the remaining thickness X should be (1/4 to 1/3) plate thickness L, but the minimum thickness X must be ≥ 0.4 mm. The upper limit of the board with heavier load can be taken, and the lower limit can be taken for the board with lighter load.
2. The misalignment S of the upper and lower sides of the V-shaped groove should be less than 0.1mm; due to the limitation of the minimum effective thickness, the V-grooved plate method should not be adopted for the plate with the thickness less than 1.2mm.
Third, Mark points
1. When setting the reference positioning point, usually leave a non-resistance area 1.5 mm larger than the positioning point.
2, used to help the optical positioning of the placement machine with the chip device diagonally at least two asymmetric reference points, the entire PCB optical positioning reference point is generally in the corresponding position of the entire PCB diagonal; block PCB The reference point for optical positioning is generally at the corresponding position of the diagonal PCB circuit board.
3. For QFP (square flat package) with lead pitch ≤0.5mm and BGA (ball grid array package) with ball pitch ≤0.8mm, in order to improve the placement accuracy, it is required to set the reference point at two diagonals of the IC.
Fourth, the craft side
1. There should be no large devices or protruding devices near the connection point between the outer frame of the panel and the inner small plate, small plate and small plate, and the space between the components and the PCB circuit board should be more than 0.5mm. To ensure the normal operation of the cutting tool.
Five, the board positioning hole
1. The whole board positioning for PCB circuit board and the reference symbol for fine pitch device positioning. In principle, the QFP with a pitch less than 0.65mm should be set at its diagonal position; the positioning reference symbol for the imposition PCB sub-board should be Used in pairs, placed at the opposite corner of the positioning feature.
2, large components should be left with positioning posts or positioning holes, such as I / O interface, microphone, battery interface, micro switch, headphone interface, motor and so on.
A good PCB designer should consider the factors of production when making imposition design, so as to facilitate processing, improve production efficiency and reduce production cost.