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Date: | Mon, 25 Jul 2011 15:18:00 +0800 |
Content-Type: | multipart/mixed |
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你好!
1. 图片中引脚周围焊锡表面的物质是什么?(颜色为黄黑色,清洗不掉)
(1).颜色为黄黑色:是助焊劑殘留. 是焊錫時平穩波(第二波峰)后無回流(錫未有流動性),平穩波中間殘留錫渣及松香
粘在PCB引腳上,一般不好清洗.建議:在不影響電器情況下,只有二次過爐(在萬不得以情況下是不準二次過爐).
(2).有時在焊錫時擾流波(第一波峰)與平穩波(第二波峰)互相沖積也會造成PCB板經過平穩波時向上爬錫灰粘到PCB板上.
2.这种现象的原因有哪些?怎样避免?
(1).焊錫時平穩波一定要有回流.
(2).兩波峰之間沖積,可找設備供應商來改善.
以上純屬個人意見:請FYI THANK!
-----Original Message-----
From: TGAsia [mailto:[log in to unmask]]On Behalf Of Eileen Xiang
Sent: Sunday, July 24, 2011 9:47 AM
To: [log in to unmask]
Subject: [TGAsia] 焊?上的?色物?接收否?
Hi all
哪位大侠能分享一下经验。图片中引脚周围焊锡表面的物质是什么?(颜色为黄黑色,清洗不掉)
现象出现在波峰焊之后,为无铅3级产品。
请问这种现象正常否,适用IPC 610E里的哪一条?是否可以接受?
这种现象的原因有哪些?怎样避免?
Thanks!
BR/Eileen
From: TGAsia [mailto:[log in to unmask]] On Behalf Of ??
Sent: Thursday, July 21, 2011 2:39 PM
To: [log in to unmask]
Subject: Re: [TGAsia] 板边白色粉尘状物质
原因分析:
1、可能是你PCB材质不易分板作业,所以在分板作业时,就会出现基板硬撕裂现象,也就是图示那种板边出现的物质。
2、可能是你PCB V_CUT设计不到位,所以在分板作业时,基板的分割切线不是正对V-CUT,因此也会出现图示那咱板边出现的物质。
影响说明:
1、在不影响装配、外观及其它性能方面外,个人认为是没有关系的。
2、对于CCD、镜头、摄像头基板页言,若基板分板后有这种物质出现,就要注意了,可能表象不会有什么特别影响,但若经过振动、摇晃等场合时,可能会出现边板物质的脱落,从而引起相应取影的不良、异物、杂点现象,所以此时个人建议制成警示,最好改变拼板方式!
以上
个人掘见!仅供参考!
----- Original Message -----
From: Kevin Qu <mailto:[log in to unmask]>
To: [log in to unmask]
Sent: Thursday, July 21, 2011 2:23 PM
Subject: [TGAsia] 板边白色粉尘状物质
All
参考附件图片,分板后有一部分板的板边发现有白色粉尘状物质,请问是什么原因导致? 有什么样的影响?
BRs!
Kevin Qu
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