soldering lots of pins... - Page 1
Forum section: electronics / beginners

author: LEDAero
author_rank: Regular Contributor
timestamp: May 12, 2015, 08:10:56 am
content: My father wants me to help him assemble his pcbs for his project.They are Arduino 'mega-shield' sized boards, with about 55 pin sockets and the same number of pins.Is there an easy way to mass-solder such simple connections?He has 50-odd boards to make and I'm sure the pro's don't sit there with a soldering iron and hand-solder 2500 pins and sockets.Any DIY/home factory advice would be gratefully received. I've ordered the parts to turn a toaster oven into a small flow oven, which has allowed us to significantly reduce the number of pth components. I've been hand-soldering the SMDs for the prototypes and while it's quite gratifying to produce a nice board, I can see my eyesight going faster than if I took a subscription to Onan's Promise.

author: Psi
author_rank: Super Contributor
timestamp: May 12, 2015, 08:17:07 am
content: If you have no SMD parts on the bottom of the PCB you could try touching the PCB bottom into a solder pot (after fluxing).You can get cheap solder pots for like $25. Obviously it needs to be large enough for your PCB though.

author: Rerouter
author_rank: Super Contributor
timestamp: May 12, 2015, 08:22:34 am
content: If he was still in layout stage, i would have said extend the pads away from the sockets, so you can drag solder down the rows, you may still be able to, it just comes down to how high a wattage your iron is (temp controlled prefered), the higher the maximum wattage, the faster you can drag as it will hold its temp and get the pads up to temp,The other key point is to give good access for an iron to come along at a 30-45 degree angle away from them,Still, seriously drag soldering will likely be the best way, get started on 2 corner pins to hold it in place, then drag down the rows feeding in solder at a comfortable rate, (flux core solder!), if you get the rate right, you will have a very low chance of forming bridges, and if you do, just lay the tip between the 2 pins and drag away, (this is where longer pads helps as the solder spreads out on its own rather than forming bridges)I've done 30 pin rows like this in under 5 seconds actual soldering time,

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 12, 2015, 08:27:48 am
content: When you get a rhythm going you can do a joint in 5s easily including cleaning the iron periodically. I'd just hammer through them myself. Probably a full day of work though. This is probably how it is done in China as wellI used to do this many years ago professionally and you can spend more time analysing shortcuts to take than actually doing it.Also flip frame (or board holder or whatever they are called these days) is required for such things however as is a relatively high power iron and a good light. Make a pattern i.e if you have a 25 pin connector, solder it in 5 pins spacings so not to heat up the board or the connector in once place too much or knock any SMD components off.SMD though - toaster oven FTW and do them first. Bugger soldering lots of them.

author: Shock
author_rank: Super Contributor
timestamp: May 12, 2015, 08:28:28 am
content: 1.5 hours with a K type or similar tip (add time for flux, soldering iron lifts and swapping boards).I would probably do that lot by hand and set up an automated system for the future if you are going to do larger volumes.

author: chibiace
author_rank: Regular Contributor
timestamp: May 12, 2015, 08:55:20 am
content: personally i enjoy soldering tons of lined up pins, helps to have something better than a $5 iron.

author: LEDAero
author_rank: Regular Contributor
timestamp: May 14, 2015, 01:45:40 am
content: Quote from: smjcuk on May 12, 2015, 08:27:48 amFTMFW! I agree.

author: SL4P
author_rank: Super Contributor
timestamp: May 14, 2015, 03:21:08 am
content: You've learned one of the first lessons about electronics manufacturing.Labour is expensive in $ and time!Next PCB or revision - plan for it to be manufactured, by someoneotherthan yourselves. (More objective)Get a quote - then you'll know where the labour input needs to be tuned!A batch of 50 is not unheard of, but pick & place setup is only cost-effective if you'll be doing moreidenticalboards later. Otherwise hand-loading and reflow is not too bad - but the choice of connectors and reduced hand wiring are a big help!

author: pickle9000
author_rank: Super Contributor
timestamp: May 14, 2015, 03:45:27 am
content: That's not really that many pins (2500) to do by hand. I would suggest that you sacrifice one board and make a pin holder out of it. That will make for a much neater and faster job.

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: May 14, 2015, 08:54:48 am
content: Quote from: smjcuk on May 12, 2015, 08:27:48 amMore like 5s per 5 pins.With some pre-fluxing and the right tip shape you can do pin headers in a continuous flow operation quite quickly.Something that helps a lot is to make a jig into which you insert the pins, then drop the board on top. Also if possible do it while the board is still panelised.

author: senso
author_rank: Frequent Contributor
timestamp: May 14, 2015, 09:10:35 am
content: Or at least use the staggered layout so that the pin headers stay pu when you flip the board.

author: smjcuk
author_rank: Frequent Contributor
timestamp: May 14, 2015, 09:28:41 am
content: Quote from: mikeselectricstuff on May 14, 2015, 08:54:48 am

author: suicidaleggroll
author_rank: Super Contributor
timestamp: May 14, 2015, 02:13:24 pm
content: 2500 pins really isn't much, you could knock that out in an hour or two easily. You'd spend FAR more time loading the boards 2-3 at a time in a small reflow oven, waiting for the bake cycle, etc.Just do it by hand, once you get in the rhythm it shouldn't take you any more than about a minute per board.

author: David_AVD
author_rank: Super Contributor
timestamp: May 14, 2015, 08:37:21 pm
content: At work we hand solder PTH boards all the time. Loading boards into a work frame can be worthwhile, but it depends on the board and component types.When the pins are in rows, you can get the time down to about a second per joint. A good soldering iron and 63/37 solder make it much easier to achieve.