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SMT焊接不良及图片说明12--IC Crack(IC 裂開 )

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核心提示:12.IC Crack(IC 裂開 )拒收 良好情況 缺點描述 : Visible or internal cracking of IC packaging and leads.可能因素 : Pac

12.IC Crack(IC 裂開 )

拒收 良好情況

缺點描述 :

Visible or internal cracking of IC packaging and leads.

可能因素 :

  • Packages’ internal moisture expansion resulting from exposure of device to temperatures above the melting point of the solder 
  • 封裝內部含有水氣 , 在迴焊高溫時氣化造成
  • Mishandling of IC packages during insertion 
  • 零件置件時壓力過大
  • Excessive thermal processing during IC manufacturing.
  • 製程中整體溫度過大 , 零件材料裂化

可行的預防方式 :

  • Ensure that moisture is not present during fabrication
  • 零件封裝時避免濕氣產生
  • Ensure that the temperature of process stay within the IC tolerance
  • 確保製程溫度在零件規格的許可範圍

重工注意意事項 :

A thermode( heated tool of a shape which conforms to the pattern of the footprints of IC ) is pressed downwards against the horizontal ends of the gullwing legs to melt all the solder joints.The footprints is cleared by lightly fluxing and passing the tip of the chisel-shaped soldering tip across all of them.Again, the footprints is fluxed once more before the IC is soldered back.

 
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