Prevention and leveling method of PCB board warpage

upamfva · 30-03-2022 04:05:39

People in the industry are well aware of the impact of PCB board warpage. If it makes it impossible to install SMT electronic components, or the electronic components (including integrated blocks) have poor contact with the solder joints of the printed circuit board, or when the electronic components are installed, some feet cannot be cut or will be cut to the substrate; In some parts of the substrate, the pads cannot contact the solder surface and cannot be soldered, etc.; one aspect of the cause of warpage of the printed circuit board is that the substrate (copper clad laminate) used may be warped, but during the processing of the printed circuit board, Because of thermal stress, chemical factors, and improper production process, the printed circuit board will also warp. Therefore, for the printed circuit board factory, the first is to prevent the printed circuit board from warping during the processing; the second is to have a suitable and effective treatment method for the warped PCB board.Get more news about Pcb Board Roller Leveller,you can vist our website!

1. Prevent the printed circuit board from warping during processing
1.1 Prevent or increase substrate warpage due to improper inventory methods
(1) Due to the moisture absorption of the CCL during the storage process, the warpage will be increased, and the moisture absorption area of the single-sided CCL is large. If the inventory environment humidity is high, the single-sided CCL will significantly increase the warpage. The moisture of the double-sided copper clad laminate can only penetrate from the end face of the product, the moisture absorption area is small, and the warpage change is slow. Therefore, for the CCL without moisture-proof packaging, pay attention to the warehouse conditions, minimize the humidity in the warehouse and avoid the bare copper clad laminate, so as to avoid the increased warpage of the copper clad laminate in storage.
(2) Improper placement of CCL will increase warpage. Such as vertical placement or heavy objects on the CCL, poor placement, etc., will increase the warpage and deformation of the CCL.

Soldered PCBA

1.2 Avoid warpage caused by improper circuit design or improper processing technology of printed circuit board.
For example, the conductive circuit pattern of the PCB board is unbalanced or the lines on both sides of the PCB board are obviously asymmetrical, and there is a large area of copper skin on one side, which forms a large stress and causes the PCB board to warp, and the processing temperature in the PCB process is high or large heat Impact, etc. will cause the PCB board to warp. For the impact caused by the improper inventory method of the cladding board, it is better for the PCB factory to solve it. It is enough to improve the storage environment and prevent vertical placement and avoid heavy pressure. For PCB boards with a large area of copper in the circuit pattern, the copper foil is meshed to reduce stress.

1.3 Eliminate substrate stress and reduce PCB board warpage during processing
Because in the process of PCB processing, the substrate is subjected to the action of heat many times and the action of various chemical substances. For example, after the substrate is etched, it needs to be washed with water, and it needs to be dried to be heated. When the pattern is electroplated, the electroplating is hot. After printing green oil and printing logo characters, it should be dried by heating or drying with UV light. Also big and so on. These processes may warp the PCB.

1.4 During wave soldering or dip soldering, the solder temperature is too high and the operation time is too long, which will also increase the warpage of the substrate. For the improvement of the wave soldering process, the electronic assembly factory needs to cooperate.