Prevention of PCB buckling-PCBA manufacturer
PCB buckling. One of the reasons for the warp of printed circuit board is that the base plate (coated copper plate) used may warp, but in the process of printed circuit board processing, due to thermal stress, chemical factors, and improper production process, the warp of printed circuit board will also occur.
Therefore, for the PCB factory, the first thing is to prevent the PCB from warping in the process.In addition, there should be a proper and effective treatment method for PCB boards that have already been warped.
Prevent the printed circuit board from warping during processing
1. Prevent or increase base plate warping due to improper inventory methods
(1) as the copper clad plate will increase warping due to moisture absorption during storage, the moisture absorption area of the single coated copper plate is large. If the humidity of the inventory environment is high, the single coated copper plate will increase warping significantly.The moisture of double-sided copper clad plate can only infiltrate from the end face of the product.Therefore, it is necessary to pay attention to the condition of the storehouse for the copper clad plate without moisture-proof packaging, minimize the humidity of the storehouse and avoid the bare copper clad plate, so as to avoid the copper clad plate in storage from increasing warping.
(2) improper placement of copper clad plate will increase warping.If there is heavy weight on the vertical or copper clad plate, improper placement, etc. will increase the warping deformation of the copper clad plate.
2. Avoid warping caused by improper circuit design or processing technology of printed circuit board
For example, the PCB plate has unbalanced conductive circuit graphics or obvious asymmetry between two sides of the PCB board, one of which has a large area of copper skin, forming a large stress, causing the PCB plate to warp, and high processing temperature or large thermal shock in the PCB manufacturing process will cause the PCB plate to warp.As for the influence caused by the improper inventory method of cladding board, PCB factory can solve the problem more easily, so as to improve the storage environment, avoid vertical release and avoid pressure.For PCB board with large area of copper skin, it is best to mesh copper foil to reduce stress.
3. Eliminate the stress of the base plate and reduce the warp of the PCB plate during processing
In the process of PCB processing, the substrate is subjected to the action of heat and various chemical substances.For example, the substrate should be washed, dried and heated after etching, the electroplating of graphic plating is hot, the green oil and the marking characters should be dried by heating or dried by UV light, and the substrate should be subjected to a large thermal shock when the hot wind blows tin.These processes can warp the PCB board.
4. When wave soldering or dip welding, the soldering tin temperature is high and the operating time is long, which will increase the base plate warping.
For the improvement of wave soldering technology, the cooperation of electronic assembly plant is required.Since stress is the main cause of base plate warping, many PCB factories believe that if the coated copper plate is baked before it is put into use, it is beneficial to reduce the warp of the PCB plate.
The function of the baking sheet is to relax the stress of the substrate sufficiently, so as to reduce the warping deformation of the substrate during the PCB manufacturing process.
The method of casserole is: the qualified PCB factory USES large oven casserole.Before putting into production, a large stack of copper coated plate is fed into the oven, and the copper coated plate is baked for several hours to more than ten hours at the temperature near the vitrification temperature of the base plate.PCB boards made from coated copper plates with baked boards have less warping deformation and a much higher pass rate.For some small PCB factories, if there is not such a large oven, the base plate can be cut down and then baked. However, when baking the board, heavy weight should be pressed on the board to keep the base plate flat during the stress relaxation process.Baking sheet temperature should not be too high, too high temperature substrate will change color.Also should not be too low, too low temperature will take a long time to relax the stress of the substrate.(PCB buckling)
Details determine the success or failure. Only by adhering to the highest quality standards for the production details of each product can we give back the customers’ trust with high quality.Jing bang always firmly believes that “quality is our life”.(PCB buckling)
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