2.54mm pin headers on a PnP - Page 1
Forum section: electronics / general

author: mpbrock
author_rank: Contributor
timestamp: May 30, 2020, 01:47:39 pm
content: Is it possible to place 2.54mm pin headers (e.g. the usual Atmega 2x3 2.54mm ISP header) on a PnP - i know you can get them in SMT footprint, but not sure how the nozzle would pick it up - unless you need special nozzles?

author: eb4fbz
author_rank: Regular Contributor
timestamp: May 30, 2020, 03:32:13 pm
content: You can order them with a PnP cap.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: May 30, 2020, 05:54:26 pm
content: You are showing a SMT part but AFAIK the same option applies to through-hole.I've never done high volume stuff, usually anything through-hole is done at second assembly by hand.But I don't see why it shouldn't work.

author: mpbrock
author_rank: Contributor
timestamp: May 30, 2020, 07:26:44 pm
content: Thats cool - thanks - do Mouser etc.. carry them with the cap?

author: Styno
author_rank: Regular Contributor
timestamp: May 30, 2020, 09:42:01 pm
content: Mouser stocks some or has them shipped directly from the manufacturer. Samtec has these in their catalog and you can order from them directly.Beware, this type of SMT connectors gave me some troubles on my (rather old) P&P:Some of my designs use an 1x8 connector and these come in reels of 250 pcs 44mm wide. They didn’t fit my feeder (the pockets in the tape are too deep) so I had to machine the slot of the brand new feeder some 4mm deeper to make it fit. The feeder also needed another modification because the transport spring didn’t have enough power to peel the top cover so it didn’t advance after a pick. I made a contraption with a bunch of extra springs to make it work.

author: SMTech
author_rank: Frequent Contributor
timestamp: May 30, 2020, 09:56:04 pm
content: As others point out you can usually get most connectors with a picking tab or piece of tape to make them more compatible with your SMT. However the very fact that you can get them in reels without those suggests that some places either use very specialised nozzles or gripper tools to place them too.As mentioned by many in threads all over, Toby in the UK can source you SAMTEC and generic parts and would understand the request if you wanted to make them do the hard work of finding the part number that has the picking tab fitted. Looking for those specific part numbers might force you to buy direct or choose the most generic sizes however.Connectors are indeed a pain as Styno points out however, you can spend a lot of money on a feeder to handle what is often quite wide tape so you do need to know that you want to place it automatically and need it to be SMT. Sometimes you get SM connectors that are simply intended to be manually placed.

author: Mangozac
author_rank: Frequent Contributor
timestamp: May 30, 2020, 10:21:26 pm
content: Has anybody tried reflowing through hole pin headers using paste in pad? I know the plastic of generically sourced ones will melt in the oven but I presume there must be some higher temp spec ones available?

author: SMTech
author_rank: Frequent Contributor
timestamp: May 31, 2020, 05:42:37 pm
content: I would only use connectors intended for that purpose (Pin in paste), on a PCB also intended for those connectors.Here's an examplehttps://cdn.amphenol-icc.com/media/wysiwyg/files/documentation/datasheet/boardwiretoboard/bwb_quickie_ctb_pip.pdfas you can see in this example its not just the plastic that's different, the pins and holes are also tweaked so all the paste isn't pushed out of the hole an you don't need as much sticking out the other side to solder too. I have also seen suggestions elsewhere that its an application where solder dispensing has an application to really get paste in the holes although I suspect that is for certain circumstances/designs.I have put a normal one through just for fun once, as expected it did melt although not as much as one might think.