The connection points (vias, vias) at each level on the circuit board limit board expansion
Most of today's circuit boards are multilayer boards, and there is a connection point (vias) between the layers and the layers. The connecting points are divided into through holes, blind holes and buried holes, and there is a point where the connection points The effect of cold shrinkage, but also indirectly caused by bending and plate Alice.
The weight of the circuit board itself will cause the board to be distorted
The general back to the furnace will use the chain to drive the circuit board in the reflow furnace in advance, that is, on both sides of the board when the fulcrum hold up the whole board, if the board above the heavy parts, or the board size is too large, It will be because of their own species and showing the phenomenon of the middle depression, resulting in bending.
V-Cut depth and connection strip will affect the amount of puzzle deformation
Basically V-Cut is the culprit to destroy the board structure, because V-Cut is in a large sheet of the original cut out the groove, so V-Cut place is prone to deformation.