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April 25, 2022
PCB assembly, the V-shaped dividing line between the two veneers and the veneers and the process edge, into a "V" shape;
After welding, it breaks off, so it is called V-CUT.
The purpose of the V - cut
The main purpose of designing V - cut is a convenient member points after PCB assembly board, board PCBA points tend to use when V - cut machine (Scoring machine), cut the PCB in advance good v-shaped grooves of huai Scoring circular blade, and then push hard in the past, some machines are automatically send board design, as long as a button, the blade will automatically move across the location of the circuit board V - cut cut the board, the height of the blade can be adjusted up and down in accordance with different V - the thickness of the cut.
Note: In addition to V-cut Scoring, PCBA Scoring also has other methods, such as Routing and stamp holes, etc.
Although PCB V - Cut above can also be used to break or break off manually, the V - the position of the Cut, but is not recommended to use broken or break off manually, the V - Cut, because it is because of the screws manually bent on PCB, it is very easy to cause PCBA above electronic parts is broken, and especially capacitance parts, thus reduce the yield and reliability of the products, some problems and even to use after a period of time will gradually emerge.
V-CUT design and usage limitations
While the V-Cut allows us to easily separate the boards and remove the edges, there are design and usage limitations.
1. A V-Cut can only Cut straight lines and Cut to the end. This means that a V-Cut can only be Cut into a straight line from the beginning to the end.
2, PCB thickness is too thin and not suitable for V - Cut grooves, generally if the thickness below 1.0 mm board, is not recommended to do V - Cut, this is because the V - Cut grooves can destroy the original PCB structure strength, when design V - Cut boards placed above are heavy parts, because the relationship between gravity and makes it easy to plate bending, this very bad SMT welding operation (cause empty welding or short circuit).
3. When the PCB is subjected to the high temperature of the backweld furnace, the board itself will be softened and deformed due to the high temperature exceeding the glass transfer temperature (Tg). If the V-cut position and groove depth are not designed properly, the PCB deformation will be more serious and the secondary backweld process will be disfavorable.
Angle definition of V-CUT
Generally speaking, V-CUT can be defined at 30°, 45° and 60° angles. The most commonly used Angle is 45°.
The higher the Angle of the V-cut, the more plates will be eaten by the V-cut at the edge of the board, and the lines on the opposite PCB will have to be retracted more to avoid being Cut by the V-cut or damaged when cutting the V-cut.
The smaller the V-cut Angle is, the better the space design of PCB in theory, but it is not good for the life of the V-cut saw blade in PCB board factory, because the smaller the V-cut Angle, the thinner the blade of the saw, and the easier it is to wear and break the blade.