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What are the hazards of using expired PCBs

  • Categories:FAQ
  • Author:SAJ
  • Origin:
  • Time of issue:2021-08-20
  • Views:0

(Summary description)As we all know, in our daily life, everything has a shelf life. Generally, as long as it is used within the warranty period, there will be no problems, but once the warranty period is exceeded, some undesirable problems will occur. Today we are mainly going to understand the hazards of using expired PCBs. The following Sanjing will introduce for everyone:
①The bonding ability of expired PCB may be degraded and deteriorated. After the circuit board is produced, the bonding ability between the layers will gradually degrade or even deteriorate over time. In layman's terms, as time increases, the bonding force between the layers of the circuit board will gradually decrease.
When the circuit board goes through the high temperature of the reflow oven, because the circuit board composed of different materials will have different thermal expansion coefficients. Under the action of thermal expansion and contraction, the circuit board may be delamination and surface bubbles may be generated, which will seriously affect the reliability and long-term reliability of the circuit board, because the layer and layer...

What are the hazards of using expired PCBs

(Summary description)As we all know, in our daily life, everything has a shelf life. Generally, as long as it is used within the warranty period, there will be no problems, but once the warranty period is exceeded, some undesirable problems will occur. Today we are mainly going to understand the hazards of using expired PCBs. The following Sanjing will introduce for everyone:
①The bonding ability of expired PCB may be degraded and deteriorated. After the circuit board is produced, the bonding ability between the layers will gradually degrade or even deteriorate over time. In layman's terms, as time increases, the bonding force between the layers of the circuit board will gradually decrease.
When the circuit board goes through the high temperature of the reflow oven, because the circuit board composed of different materials will have different thermal expansion coefficients. Under the action of thermal expansion and contraction, the circuit board may be delamination and surface bubbles may be generated, which will seriously affect the reliability and long-term reliability of the circuit board, because the layer and layer...

  • Categories:FAQ
  • Author:SAJ
  • Origin:
  • Time of issue:2021-08-20
  • Views:0
Information

As we all know, in our daily life, everything has a shelf life. Generally, as long as it is used within the warranty period, there will be no problems, but once the warranty period is exceeded, some undesirable problems will occur. Today we are mainly going to understand the hazards of using expired PCBs. The following Sanjing will introduce for everyone:

 

①The bonding ability of expired PCB may be degraded and deteriorated. After the circuit board is produced, the bonding ability between the layers will gradually degrade or even deteriorate over time. In layman's terms, as time increases, the bonding force between the layers of the circuit board will gradually decrease.

 

When the circuit board goes through the high temperature of the reflow oven, because the circuit board composed of different materials will have different thermal expansion coefficients. Under the action of thermal expansion and contraction, the circuit board may be delamination and surface bubbles may be generated, which will seriously affect the reliability and long-term reliability of the circuit board, because the layer and layer of the circuit board may be broken by the delamination of the circuit board. The vias between the holes cause poor electrical characteristics. The most troublesome thing is that intermittent defects may occur, and it is more likely to cause micro short circuits (CAF).

 

 

②Expired PCB may cause oxidation of the solder pads (pads) on the surface of the PCB. Oxidation of the solder pads will cause poor soldering, which may eventually lead to functional failure or risk of parts dropout. Different surface treatments of circuit boards have different anti-oxidation effects. In principle, ENIG (chemical nickel gold) must be used up within 12 months, while OSP (copper protection agent) must be used up within six months. Therefore, it is recommended to follow the shelf life of the PCB board factory to ensure quality.

 

However, the OSP board can generally be sent back to the board factory to wash off the OSP film, and then a new layer of OSP is applied. It should be noted that the copper foil circuit of the OSP will be damaged when the OSP is removed by pickling, so it is better to The board factory knows if it can reprocess the OSP film. However, the ENIG board cannot be reprocessed. It is generally recommended to perform "press-baking" and then test whether there is any problem with the solderability.

 

③The expired PCB may absorb moisture and cause the board to burst. After the circuit board absorbs moisture and undergoes reflow soldering, it may cause problems such as popcorn effect, bursting or delamination. Although it can be solved by baking, not every kind of board is suitable for baking, and other quality problems are prone to occur during baking.

 

Generally, OSP board is not recommended to be baked, because high-temperature baking can easily damage the OSP film. However, if it is necessary to bake it under special circumstances, it is necessary to pay attention to the bake time not to be too long and the temperature not to be too high. The pad is oxidized, which affects welding.

 

The above is the content shared by Sanjing about the hazards of using expired PCBs. Do you understand now?

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