午夜夜伦鲁鲁片免费无码-国产裸拍裸体视频在线观看-亚洲无码视频在线-学生妹亚洲一区二区-国产亚洲欧美日韩亚洲中文色

鑫景福致力于滿足“快速服務,零缺陷,輔助研發”PCBA訂購單需求。
行業新聞
行業新聞
Harm of Lead in PCBA Processing
29Oct
Andy 0條評論

Harm of Lead in PCBA Processing

Harm of Lead in PCBA Processing


PCBA processing is to connect various electronIC components on PCB board through surface mount (SMT), plug-in (DIP) and other electronIC assemblies. PCBA process flow mainly includes SMT, AOI, DIP, FCT testing and other processes. Due to the size difference of electronic components, there will be different processes and requirements in assembly and insertion. The assembly density of PCBA is relatively high, and the SMAll size and light weight of electronic products also have certain changes and requirements in mounting. The reliability, seismic resistance and excellent weldability of the products have high requirements for the hardware and software facilities of PCBA processing.



circuit board


I. Hazards of lead

Lead has been used in various industries for more than 1000 years, and lead is used in PCB manufacturing. At present, the global annual consumption is about 5 million tons, of which 81% is used for batteries, followed by lead oxide white paint and weapons, both of which are also used for about 10%. They are the three places where large quantities of lead are used. In fact, only 0.49% of them are actually used in the circuit board manufacturing and electronic product welding industry. However, due to its wide distribution range and very difficult recovery and reuse, the pollution caused by them cannot be considered as serious! The harm of lead can be seen from this

Lead is the "killer" of cells. When the blood lead concentration reaches 15mg/100ml, it will cause children's growth retardation and mental retardation. The younger the age, the more serious the nerve damage. Lead poisoning is characterized by excessive movement, excitement, poor sleep, loss of appetite, frequent urination and enuresis, irritability, moodiness, and even poor hearing and language expression. The harm of lead is very terrible, so it is urgent to make the circuit board lead-free.

The harm of lead in PCBa blood

Lead compounds easily infiltrate into groundwater, which will become a potential crisis of drinking water. Taking Japan as an example, its environmental protection regulations require that the lead in groundwater should not exceed 0.3 ppm (0.3 mg/l). As for the United States, in its EPA40 CFR141, it is stipulated that the lead content in drinking water is more strict to a limit of only 15 ppb (0.015mg/l). For example, according to the TCLP poison dissolution test in EPA 40 CFR261 of the United States Environmental Protection Agency, the maximum dissolution amount of lead can only be analyzed to 5mg/l, while the loss amount of lead in various solder joints in general circuit board manufacturing after abandonment in the nature is hundreds of tiMES higher than that in the above dissolution test. How can the danger of lead be so dangerous that it can not be feared carefully! So it is imperative to make circuit boards in electronic products lead-free.

點擊
然后
聯系
主站蜘蛛池模板: 日韩少妇白浆无码系列| 久久久国产精品亚洲一区| 无码av无码免费一区二区| 日本最大色倩网站www| 精品亚洲国产成人av网站| 北条麻妃无码| 久久国产亚洲欧美久久| 国产久青青青青在线观看| 一出一进一爽一粗一大视频免费的| 国产成人精品亚洲午夜| 欧美不卡一卡二卡三卡| 暖暖视频 免费 日本社区| 国产欧美性成人精品午夜| 国产精品99久久免费观看| 久久无码潮喷a片无码高潮| аⅴ资源天堂资源库在线| 久久精品国产99久久久小说| 国产精品99久久久久久www| 性夜影院爽黄e爽| 久久国产劲爆∧v内射-百度| 欧美喷潮久久久xxxxx| 国产成人无码精品xxxx| 久热这里只有精品12| 免费无码又爽又刺激一高潮| 精品久久久无码中字| 亚洲中文字幕无码av正片| 国产精品免费福利久久| 国产在线高清理伦片a| 精品人妻无码一区二区三区抖音| 国产精品偷伦视频观看免费| 无码亲近乱子伦免费视频在线观看| 亚洲精品国产高清一线久久| 麻豆av传媒蜜桃天美传媒| 亚洲一区精品无码色成人| 午夜影视啪啪免费体验区| 久久狠狠中文字幕2017| 免费天堂无码人妻成人av电影| 一本大道在线无码一区| 芙宁娜被?吸乳羞羞A片| 91精品少妇一区二区三区蜜桃臀| 亚洲精品tv久久久久久久久|