Through Hole Component Support during soldering - Page 1
Forum section: electronics / general

author: forrestc
author_rank: Unknown
timestamp: July 20, 2017, 08:14:58 am
content: In our assembly line, we tend to have to solder a few through hole components (mostly connectors) on every board. Today, we use the same methods one would use to assemble a kit - basically insert the shortest component, flip the board, solder into place, repeat with the next shortest component, and on and on. This process tends to be slow.We'd like to move to a process where we can insert all the components, then flip the entire board. This should permit splitting of the insertion and the soldering tasks, improving takt time, etc. It will also enable the addition of a soldering robot into the line at some point (instead of a very expensive to buy and run selective soldering machine).Long ago, back in the days before surface mount was prevalent, there seemed to be lots of tools to permit an entire board of hand inserted, unsoldered components to be flipped over for soldering. The simplest one was a board with foam on it which you put over the circuit board, held tightly and flipped. This worked ok but wasn't even close to perfect. Others were more sophisticated. Unfortunately either these products are completely extinct or perhaps just as likely I just haven't hit on the magic google incantation to make them appear in my search window for further perusal. I specifically remember one which was a quickly adjustable and lockable bed of nails.My fallback position is to 3d print a jig for every board for support. I'd rather not do this just because of the time involved. I'd rather find something quick and easy which works.Anyone know what I should be searching for?

author: tszaboo
author_rank: Super Contributor
timestamp: July 20, 2017, 08:22:22 am
content: The search term is:"PCB assembly service""Selective wave soldering machine"If you need to hand solder more than 2-3 board in house, you are doing something wrong. The reason these jigs cannot be bought anymore, is because they are not relevant anymore. There are good assembly houses all over europe, solving any assembly requirements, and strange requests. I dont think it it would be otherwise in the US.

author: SMdude
author_rank: Frequent Contributor
timestamp: July 20, 2017, 08:25:07 am
content: I have thought about this and a dirt cheap simple fast way might be some plaster of paris, make a mould of a completed board(wrap some tape around caps etc to make the holes a bit larger).Then you can put the mould over the top of the board after all the through holes have been put through, flip and solder.Disclaimer, I have never tried this, but will when the need arises..Cheers

author: ar__systems
author_rank: Frequent Contributor
timestamp: July 20, 2017, 06:54:20 pm
content: Quote from: NANDBlog on July 20, 2017, 08:22:22 amThat's too general a statement to be true. So what, if you have to solder connectors to 20 boards, you run to an assembly service? that's ridiculous. A hired assembler will do 20 boards for me in a 2-3 hours, with a total cost around $50. Assembly service will take at least a week, and they will cost a lot more.

author: jmelson
author_rank: Super Contributor
timestamp: July 20, 2017, 07:39:46 pm
content: Quote from: SMdude on July 20, 2017, 08:25:07 amThat's brilliant! But, there might be a better material than plaster! I can think of some modelling clays and insta-pak that will harden after a certain time, without making all the dust that plaster would.I suppose you could paint the plaster to keep it from making dust, though.Jon

author: 2N3055
author_rank: Super Contributor
timestamp: July 20, 2017, 08:10:32 pm
content: How about these :http://www.tme.eu/en/details/bl142042/soldering-devices-others/isel/http://www.tme.eu/en/details/bl142043/soldering-devices-others/isel/and more expensive ... (i have two of these)http://www.tme.eu/en/details/idl-pcsa-1/soldering-devices-others/ideal-tek/pcsa-1/http://www.tme.eu/en/details/idl-pcsa-2/soldering-devices-others/ideal-tek/pcsa-2/That helps ?

author: nisma
author_rank: Regular Contributor
timestamp: July 20, 2017, 08:20:27 pm
content: Here in europe this type of equipment is cheap if you not buy from farnell or similar .Example here,http://gie-tec.de/w2d6project/00a7f14744a8bf4e276f583f04123efd/db_142042.pdfIt is not difficult to make, and the big handle is nice that allows it to solder it inclined. The foam is 40mm thick.http://www.nutsvolts.com/magazine/article/september2011_Collier.The foam is only 1" thick and as my experience is not working. Further it should be of conductive type.Hope this helps

author: forrestc
author_rank: Unknown
timestamp: July 20, 2017, 08:41:18 pm
content: Quote from: NANDBlog on July 20, 2017, 08:22:22 amWe have a wave solder machine in-house. We have actually discovered that for boards with less than a certain number of pins it is actually faster to solder them by hand (put connector on board, solder repeat) than do all of the handling related to the wave solder machine (pre-connectorize, put on tray, transport trays to wave machine, load board into wave machine, remove board, put on tray, transport back to inspection area, inspect and cleanup). About all we do is the higher pin count boards (>50 pins or so), and even they are questionable when you add the setup time for the wave solder machine itself.Part of what is driving this is the desire to over the next year or so move to some sort of automation and eventually rid ourselves of the wave solder machine. A 10-20K USD soldering robot is not out of the question here. A $50K + nitrogen system or consumable nitrogen + lots of energy selective solder machine is much less attractive. Unfortunately, every soldering robot I've encountered needs to have the board inverted to solder the pins, and also leaves the fixturing up to the user (or have a service to build one for each board for lots of money).So the thought process is this: If we can solve the board flip problem in a way that is inexpensive to do on a per-board basis (automatic fixturing, etc), then this both cuts down the time needed for hand assembly now, and also provides us a solution for the soldering robot when the financial numbers work for the robot. If we can't resolve the board flip problem in a reasonable fashion, then we need to buy the selective solder machine (no flip required) or just continue the way we are.One final note: I've toured several assembly lines recently. Every one I've been into employ a connection of workers who solder connectors on boards by hand. There was one in particular I remember which had a nice shiny selective solder machine which was not turned on, and in another area, a group of employees soldering connectors. I asked about why not use the selective solder machine, and their response was that they had found that the cost of setting up the selective solder machine wasn't worth it for all but the larger runs, so they still hand-soldered connectors on most of the smaller batches. I don't remember which threshold they said, but it was well over 100 boards.

author: forrestc
author_rank: Unknown
timestamp: July 20, 2017, 08:44:04 pm
content: Quote from: jmelson on July 20, 2017, 07:39:46 pmI too, find this intriguing. Not only that, but with the right material it could be trimmed. I hadn't even thought about plaster/clay/expandable foam/etc, which can be used for moldmaking....

author: jmelson
author_rank: Super Contributor
timestamp: July 20, 2017, 09:55:10 pm
content: Quote from: forrestc on July 20, 2017, 08:41:18 pmI have a board I do that has 40 small connectors on it, Some are just 0.1" grid single and dual-row bare headers, some Molex-type connectors. There are no SMT parts on the back of the board. I got a big Chinese solder pot and dip the board in the solder. I flux the back of the board before inserting the parts.So, this is kind of manual wave soldering. You are right, it would not make sense for just a few small connectors. But, it really works when you have 40 of them!Jon

author: KL27x
author_rank: Super Contributor
timestamp: July 20, 2017, 10:55:56 pm
content: Better if the parts hold themselves. If you can tweak the holes to be tighter, you might not need to mess with jigs.Personally, I think plain open cell foam is going to be faster and easier and more effective than a rigid mold. With a sharp knife or a foam cutter and some wood glue, you can quickly build up or remove areas where needed, and you don't have to be exact.Another option is perhaps some kind of goo. Like the white stuff they used to put around caps and whatnot. So when you stick the parts in, they stay?

author: tautech
author_rank: Super Contributor
timestamp: July 20, 2017, 11:32:15 pm
content: Quote from: KL27x on July 20, 2017, 10:55:56 pmI agree and some improvement on the board backed foam arrangement the OP is using should be the key and easy to accomplish.I'd use a 6mm HD conductive foam like this stuff and layer and/or carve it to accommodate the different component height requirements.http://nz.element14.com/multicomp/038-0016/high-density-foam-305x305x6mm/dp/1687855?ost=1687855&categoryIdBox=&selectedCategoryId=&searchView=table&iscrfnonsku=false

author: forrestc
author_rank: Unknown
timestamp: July 21, 2017, 12:18:47 am
content: Quote from: tautech on July 20, 2017, 11:32:15 pmI'm going to experiment with this.My experience with the old style foam-on-backing method was that while it worked really well when your components were similar height (i.e. through hole resistors, small caps, transistors), but as soon as you got to where you had significant variation in height, things quit working so well since you were both over and undercompressing the foam. Never thought about trimming it though....My original thought was to 3d print a basic jig to which you attached either foam or some other compressible material (springs, etc) to actually do the holding in place. Doing a mold combined with some foam glued inside it might acutally be the best of both worlds. ... but if I can just get away with cutting foam that would work.I also like the idea of combining it with a holder like as in:Quote from: nisma on July 20, 2017, 08:20:27 pm

author: forrestc
author_rank: Unknown
timestamp: July 21, 2017, 12:27:18 am
content: Quote from: jmelson on July 20, 2017, 09:55:10 pmSo, I have to devolve into the history about the wave solder machine.When I first started manufactuing products, I was hand soldering everything. Then someone told me about the molten pot of led dip process. Made things much faster, but it was one of the most horrible things I've ever done.Dip flux, use a rival indoor crock grill as a preheater. Once the flux was active, dip it into a electric skillet full of lead. The flux fumes were atrocious, had to use a big face mask, gloves, etc. etc. etc. Just not pleasant at all to operate. For someone else this probably was ok, but for me it was just horrible for the year or so I assembled that way.At some point I decided that I couldn't do it anymore and bought a wave solder machine, which was much nicer. We hand inserted and wave soldered everything for quite some time. A few years back I bought the SMD line, and the wave has been relegated to high pin count connectors for quite some time now.

author: tautech
author_rank: Super Contributor
timestamp: July 21, 2017, 12:39:50 am
content: Quote from: forrestc on July 21, 2017, 12:27:18 amWhat flux did you use ?Recently I've scored from another member a quantity of Multicore PC26, it's very liquid and can be brushed or sprayed for wave soldering. Sure the datasheet (attached) says the fumes should be avoided but I wonder if it would be better that what you have used.

author: forrestc
author_rank: Unknown
timestamp: July 21, 2017, 12:49:59 am
content: Quote from: tautech on July 21, 2017, 12:39:50 amI'm not sure which Kester flux I would have used. I know we use 959 in the wave today. It wouldn't have surprised me if it was something like 979 which is water based, which might have been part of the horriblemess)

author: mairo
author_rank: Unknown
timestamp: July 21, 2017, 10:22:14 am
content: As 2N3055 posted above,this type of jigis probably going to do the job!? The good thing about this particular jig is that you can position it flat or on an angle during soldering.

author: nisma
author_rank: Regular Contributor
timestamp: July 21, 2017, 11:39:39 am
content: or ordineringhttp://www.tme.eu/en/details/bl142043/soldering-devices-others/isel/trough tme , as tme ship to usa for 10$.as reference annother price,https://www.schukat.com/schukat/schukat_cms_en.nsf/index/CMSFFEDE67DB7032C11C1256DF1003EF651?OpenDocument&wg=T3511&refDoc=CMSD9880E5DB65EE9A9C1256D6E0044F0C1&kb=T3511If you don't use the springs,http://www.electro-tech-online.com/attachments/pcb-holder-gif.45266/I would suggest to buy additional pcb holder rails and ask tme if there could supply it, or you start with the frame and thenorder online the cut to order rails and hw items in order to increase capacity for smaller boards. as probably only 2 rows of boards are possible withstandard combination. The ones i have ordered was with 3 movable rails, probably this have changed.