On Tue, Mar 29, 2011 at 8:28 AM, Chris Kleeschulte <
laconia@...>wrote:
>
>
> Here is my real question about through hole parts and boards. There are a
> lot of parts the have flat through hole leads. Of course your drill bit
> yields a round hole. Even further, some pads intended for those flat (or
> square pins) are really thin (like 12 mils), such as the .1" pin headers
> used a lot on dev and breakout boards. The problem I am having is getting a
> good solid connection to the board with these parts. The pins always seem
> very precariously attached to the pcb since the pins are attached by so
> little copper on the board and the different shape between the hole and the
> pin. Do you guys glue the plastic headers down? Is this a good idea? What
> about the different shapes? Is the solder supposed to bridge the gap there
> or is there another way? I know solder really is not a structural
> component,
> but without some bonding agent, it really is, right?
>
> With SS boards you don't get the strength of the PTH that is normally there
on DS.
I try for the smallest possible hole and the maximum amount of copper for
the pad. Bonding of the copper to the board comes from the adhesives of the
copper foil to the laminate. Try to maximize that surface area. Bonding
strength between the part lead and the copper comes from the solder fillet,
again you want to try to maximize that. Also note that a too hot a soldering
iron tends to lift pads.
I try to avoid true slotted parts when possible on my toner transfer
boards, but when necessary I drill multiple holes and bridge them with small
router bit to open up the slot.
One example of avoiding slotted holes:
The dirt common 2.1mm power connector comes in the common lug style and an
uncommon pin style
http://goo.gl/eUypVvs
http://goo.gl/CHu7SI stock up on the tapered pin style.
-carl
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