Karen,
This is a REALLY generalized question, so I suspect you may get a wide range of answers. It depends on your situation, your equipment & processes (wave solder, selective solder, cleaning, etc), and also very much on PCB type, thickness, layout, and density.
I'll try to answer with a few specific examples from my own experience.
- TH soldering to very thick PCBs with metal cores on heavy copper weights can require a little more effort to heat the PCB sufficiently to get proper solder fill to meet IPC-610 requirements. Equipment selection is critical, and designs should be optimized as best as possible to allow soldering.
- Wave soldering vertically mounted TH parts can be sometimes problematic to keep parts "vertical" through the wave. This is best overcome with fixturing.
- TH soldering in general of parts without standoffs can also be problematic. It is generally a bad idea to flush mount, as you need to leave spacing not only for your solder fillets, but also cleaning. I've also TH soldered a multitude of connectors where the spacing of the panel-mount flange must be tightly controlled with relation to the PCB surface - also best controlled with fixturing.
- TH soldering of connectors with high pin densities and/or low-standoffs can make inspection of inner pin solder fillets difficult. With some sort of solder bath or rework equipment, removing multiple leaded components can also be an issue.
- Another component that can be difficult is the hybrid connector, with some SMT pads and some TH leads on the same part. You will see a multitude of past TN emails on the best methods to handle these as well.
I hope these examples help, but again, the question is pretty generalized.
Kevin
-----Original Message-----
From: Karen Tellefsen [mailto:[log in to unmask]]
Sent: Monday, September 28, 2009 11:34 AM
To: [log in to unmask]
Subject: [TN] What through-hole components cause the most process issues?
This is for all you process engineers.
What though-hole components cause the most trouble:
those with many high density pins
components with a lot of heat capaticty, such as heat sinks, transformers,
etc.?
Anything else?
Do you wave solder glued SMT components, are any of these problematic?
Thanks for your help.
Karen Tellefsen - Electrical Testing
[log in to unmask]
908-791-3069
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