I don't believe the pin would cause any issues, except for the fact that trimming hard pins (brass, alloy 42, Kovar, etc.) after soldering can cause the solder joint to fracture and it is often not visible even at 20x, which is why it is a practice frowned upon by IPC and J-STD, at least for standard component leads in plated through holes. They recommend re-soldering after trimming. This brings up two questions; (1) is it absolutely necessary to trim the pin, from an interference fit standpoint or from a minimum electrical clearance standpoint, and (2) can these pins be either purchased at the right length to preclude trimming, or can they be trimmed prior to placement and reflow? If mill-max cannot provide a pin of just the right length, then consider looking at Autosplice. They have been very accommodating in making custom pins and tooling.
But from a reliability standpoint, in the old days we used to insert (press-fit) interfacial pins into plated-through vias as a matter of routine, just to make sure the vias were reliable, and sometimes had to trim them after wave solder. I don't see any difference between this practice and what you are doing, albeit a slightly larger plated through hole. The only real issue is the trimming after soldering. If there are only a few per board, then just have them touch them up after trimming. But if they are only used for test, even if the solder joint fractures from trimming it should not present a reliability issue, because the plated through hole will still provide a reliable path from the source layer to the next. I doubt very much that they could fracture such that they would come loose.
-----Original Message-----
From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of Gary Koven
Sent: Friday, April 24, 2015 2:30 PM
To: [log in to unmask]
Subject: [DC] Pogo Nail Trim
We would like to purchase this off-the-shelf pogo nail whichmust be trimmed after soldering: Mill-Max MPN 9228-0-00-80-00-00-38-0 https://www.mill-max.com/products/datasheet/recpin/9228-0-00-80-00-00-38-0 Essentially this is a 40mil brass nail head pin to be soldered into a44mil hole, then trimmed.
We would like to understand if there are any concerns withstress on the PCB and hole plating after trimming. We don t have IPC-CM-770 in house and are not certain whetherthis, or any other IPC spec, would characterize lead trim of hard metallicmaterials not meant to be trimmed. Any advice would be appreciated.
TIA and Best Regards,
Gary M. Koven, C.I.D.
InVue Security Products
Charlotte, NC, USA
Board Of Directors, RTP Chapter
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