亚洲啊啊 I 黄色精品在线观看 I 国模吧久久 I 亚洲蜜臀av国产aⅴ综合小说 I 久草一区二区 I 亚洲欧美中文日韩v日本 I 毛片免费视频观看 I 九九视频在线观看视频6 I 亚洲免费在线观看 I 欧美三级韩国三级日本三斤 I 国产av一区最新精品 I 国内精品伊人久久久久av影院 I 国产成人福利 I 中国精品一区二区三区 I 亚洲一区二区三区中文字幂 I 午夜视频 I 免费观看中文字幕 I 国产精品热久久高潮av袁孑怡 I 干夜夜 I 三浦惠理子aⅴ一二三区

Common problems are easy to occur in the process of circuit board operation, personnel circulation, equipment gravity and other factors, through hole component insertion, In-circuit testing, single board segmentation, circuit board installation, circuit board point riveting, screw installation and other processes. This kind of crack generally originates from the upper and lower metal bonding ends of the device, and spreads to the inside of the device at 45 ℃. This type of defect is also the most common type of defect.

1. Mechanical stress factors:

(1) Test probe causing PCB bending

(2) The Influence of PCB Bending and Fracture on PCB

(3) The installation of the suction nozzle (the pressure of the suction nozzle is too high, the distance between the pressures is too deep) and the impact caused by the fixation of the middle claw.

(4) Excessive tin (such as a regular liner at one end).

2. Principle of mechanical stress crack generation:

Chip capacitors are a brittle material. If the PCB board is bent, it will be subjected to a certain amount of mechanical stress impact. When the stress exceeds the strength of ceramic bodies with patch capacitors, bending cracks will occur. Therefore, the cracks generated by this bending only appear after welding.

I have learned the precautions to pay attention to when using SMD capacitors. Although SMD capacitors are small, the compression energy should not be too large. We should pay attention to the necessity of protective measures.