物料尺寸有沒有偏上下限? 要是手銲 ok, 應是應力問題.

YangYanBo wrote:
> 怎么有点像油墨发白啊？
> 建议用PCB板过波峰焊后看是否有此情况？如果没有，可能是你在压入插针时产
> 生的外力所致。
>
> ------------------------------------------------------------------------
> *发件人:* TGAsia [mailto:[log in to unmask]] *代表 *Wang, Jennifer
> *发送时间:* 2010年9月30日 10:19
> *收件人:* [log in to unmask]
> *主题:* Re: [TGAsia] 请教：此种情况是IPC-A-610D中的白斑还是微 裂纹
>
> 各位坛友
>
> 今日在生产过程中，看到了一个现象，就此异常现象是属于白斑还是微裂纹产生
> 了争议，照片如下。
>
> 附件中可见的焊点为压接的插针；整个PCBA有压接插针的地方有如图所示的异常
> 情况，其它焊接点周围及板面正常。
>
> 在试验过程中，插针压接在PCB上以后，并无白斑或微裂纹等异常情况；当过完
> 波峰焊之后，如图所示的情况就出现了。请问此种情况是应属于白斑还是微裂纹？
>
> 此种异常情况出现的可能原因有哪些？（注：插针压接及波峰焊过程我们试验过
> 程都做了记录，没有异常）
>
> 请指教！
>
> *王萍*
>
>
> *
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