11个回应

  1. JEFF.TSAI
    2019/01/17

    感谢熊大的回覆
    SMT产线怕第一层PIH的锡S/S置件后过Reflow锡会流到C/S面, 造成另一面Type pin脚插不进孔内, 会跪脚.
    有风险的设计产线似乎不买单 =.=

    Reply

    • 188金宝搏苹果下载
      2019/01/17

      Jeff,
      所以你的意思是说,双面都有Type-C连接器,且PIN脚对插在同一个PTH孔,这样的确可能会有问题,只是第一面不印锡,可能造成焊锡量不足,焊锡孔洞,所以第二面的锡量要多注意。

      Reply

  2. JEFF.TSAI
    2019/01/17

    hi 熊大你好~
    我在排一块PCBA,客人要求评估板子的正反面在同一个位置都要打上Type-c connector(SMD type)定位Pin0.6mm,板子厚1.6mm
    请问这样可以打吗?
    我的想法是投入面dip孔先不上锡,打产出面时在上锡并打上第二颗TYPE-C,请问这样的方式可行吗?会不会有什么问题
    谢谢

    Reply

    • 188金宝搏苹果下载
      2019/01/17

      Jeff,
      基本上是第一面是的孔洞(PTH)可以印锡膏做PIH制程,没有问题的,因为你的PIN脚长度只有0.6mm而板厚有1.6mm,所以锡膏不会溢到背面,我们的经验是孔洞内的锡膏都填不满。

      Reply

  3. Ming-Ching Chou
    2017/01/20

    Dear Sir,

    One interesting paper can be an example of that I described in 2.:
    https://www.mpif.org/AboutMPIF/PDFs/papers/outstanding15.pdf

    Best
    Chou

    Reply

    • 188金宝搏苹果下载
      2017/01/22

      Chou,
      Thanks for the information.

      Reply

  4. Ming-Ching Chou
    2017/01/16

    Dear Sir,

    I think there are three reasons for higher the remelting point of the solder alloy after fist soldering process.

    1. The element ratio of the alloy has been changed after first melting just like you described above.

    2. The solder paste is composed of two particle type solders, which the low temperature solder is minor and high temperature solder is the most. After re-flow process, the lower one melting firstly and soon solidified by changing its element ratio to nearly the same as the high temperature one due to diffusion.

    3. Even the element ratio of the alloy has no change after the re-flow soldering, the particle type solder has high surface energy due to its relatively large surface area to volume ratio, this can be seen as an effect come from Quantum mechanics. You can image that the smaller particle the closer to the status of melting, if the particle size is as small as one atom one particle, it is really melted even room temperature. Put a lot of this kind particles together will soon to form a solid solder, which need the temperature rise to the melting point for remelting.

    Best

    Chou

    Reply

    • 188金宝搏苹果下载
      2017/01/17

      Chou,
      Thanks for the information share. You give more directions to study this topic.

      Reply

  5. Lin Yi Hsien
    2016/10/05

    版主,我突然想到会不会跟EMI有关呢,是不是直接导到金属去外壳上

    Reply

  6. Lin Yi Hsien
    2016/10/02

    请问版主,一开始你放的这张电路板照片,板子看起来蛮厚的,好像超过1.6T,请问厚度多少? RJ45和USB附近的板边好像有局部镀金?请问用意是什么呢?感谢版主的回答。

    Reply

    • 188金宝搏苹果下载
      2016/10/03

      Lin Yi Hsien
      板子是1.6mm厚度。
      镀金一定有特别目的,但这不是我的专长,所以无法回答你。

      Reply

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