PCB新聞 - 表面貼裝焊接的缺陷及其預防措施

What are the defects of surface mount soldering and their preventive measures
Pay attention to product innovation in terms of energy saving and emission reduction. 印刷電路板工廠必須學會重視互聯網科技，通過綜合行業整體知識，實現自動化監控和智慧管理在生產中的實際應用.
What are the defects of surface mount soldering and their preventive measures:
1. Poor wetting
Poor wetting refers to the fact that the solder and the solder area of the substrate are wetted during the soldering process, 不會產生金屬對金屬反應, 導致漏焊或更少的焊接故障. The reason is mostly the surface of the weld zone
It is caused by contamination or welding flux or compound layer formed on the surface of the object to be joined, 如銀表面的硫化物, 錫表面的氧化物, 等.
出現潤濕不良. 此外, 當殘餘鋁, 鋅, 等. 在焊料中超過0.005%, 由於焊劑的吸濕性，活性降低, 也可能出現潤濕性差的情况. crest
If there is gas on the surface of the substrate during soldering, 這種故障也容易發生. 因此, 除了執行適當的焊接工藝外, 基板表面和部件表面必須處理好.
防污染措施, 選擇合適的焊料，設定合理的焊接溫度和時間.
二, bridging

The causes of bridging are mostly excessive solder or severe edge collapse after solder printing, 或基板焊接區域的尺寸超出公差. 貼片放置偏移, 等., 在SOP中,
QFP電路趨於小型化, 並且電橋會導致電力短路，影響產品的使用.
As a corrective measure:
1. To prevent poor solder paste collapse
2. The size of the soldering area of the substrate must meet the design requirements
3. The placement position of the SMD should be within the specified range
4. The substrate wiring gap and the coating accuracy of the flux must meet the specified requirements
5. Formulate appropriate welding process parameters to prevent mechanical vibration of the welding machine conveyor belt
Three, cracks
When the soldered 印刷電路板 剛離開焊接區, 由於焊料和粘合零件之間的熱膨脹差异, 在快速冷或快速熱的作用下, 由於凝固應力或收縮應力的影響,
SMD基本上會產生微裂紋, 在衝壓和運輸過程中，必須降低SMD上的衝擊應力 印刷電路板 焊接後. Bending stress surface mount 產品 are in design
When timing, 應考慮縮小熱膨脹間隙, 正確設定頂部加熱和冷切條件等條件, 選擇延展性好的焊料.
四, solder ball
The production of solder balls mostly occurs when the solder is scattered due to the rapid heating during the soldering process. 此外, 這也與印刷有關, 下垂, 錯位, 和焊料污染.
Preventive measures:
1. 避免焊接加熱過快和不良, 按照設定的加熱工藝進行焊接.
2. Defects such as sag and misalignment of solder printing should be deleted
3. The use of solder paste should meet the requirements without bad moisture absorption
4. Implement the corresponding preheating process according to the type of welding
5. Suspension Bridge (Manhattan)
Poor suspension bridge means that one end of the component leaves the soldering area and stands upright or obliquely upward. 原因是加熱速度太快, 加熱方向不平衡, and the choice of dry paste
The problem is related to the preheating before welding, SMD本身的形狀, 和潤濕性.
Preventive measures:
1. The storage of SMD must meet the requirements
2. The size of the substrate pad length should be properly formulated
3. Reduce the surface tension generated on the end of the SMD when the solder melts
4. The printing thickness of the solder should be set correctly
5. Adopt a reasonable preheating method to achieve uniform heating during welding
iPCB愛彼電路 已通過ISO9001:2008認證, ISO14001, UL, CQC和其他品質管制體系認證, 產品標準化、合格 印刷電路板 products, 掌握複雜工藝科技, 並使用AOI和Flying Probe等專業設備控制生產和X射線探傷機. 最後, 我們將使用雙FQC外觀檢查，以確保按照IPC II標準或IPC III標準裝運.