从照片上看象是白斑。微裂纹和白斑的外观区别主要是分散状态还是连成一片。原因可能是你在压入插针时，在层压板内层产生的应力，受热后发生了内部分层。如果想更准确地确认和进行原因分析，建议做剖面分析。









Best Regards,



NEW：10月25-29日深圳 IPCWorks Asia众多技术活动期待您参与！



James Liu 刘春光

Director, Industry Programs 工业项目总监

IPC China

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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: Listserv TGAsia

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！

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王萍



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