pcb assembly question

Erik Friesen

I am hand assembling some boards, 9.5"x11.5", which are mixed with smt and through hole. I have close to 375 through hole pins. How do assembly houses do a board this big? Do they glue all the pieces in and dip them in a large pot, or what? I have been gluing my parts on and flipping the board, but that is time consuming gluing all those pieces, plus the glue can make a mess.(CR)

WBA Consulting

The most common method is using a wavesolder machine (Wikipedia link). Simple explanation:

Load through-hole parts into the board.
Load board onto the wave conveyor.
Board has flux applied (either sprayed on or foamed)
Board is preheated to precise temperatures to properly activate the flux.
Board goes across a solder pot that is flowing at a precise temperature and rate to solder all leads at the same time.
Board is cooled (usually just fans and room temp air)
Board is cleaned (ran through an aqueous cleaner for water soluble flux or flux-remover for removing excess no-clean flux)

Another alternative is using a slective wave soldering machine. It is basically a small wave that is on an X-Y gantry and computer controlled just like a CNC machine. At work we have a KISS-102 from ACE Production Technologies

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Andrew Williams
WBA Consulting
WBA-TH1M Sensirion SHT11 Module
Special Olympics Polar Bear Plunge, Mar 20, 2010
Propeller-Based Reverse Geo-Cache Birthday Present Project

Leon

For through-hole parts I used to use an assembly frame. The frame was adjustable and could hold a number of boards, the parts were inserted and the lid was closed, holding the parts in place with a large foam rubber pad. The frame was then inverted and the leads soldered. The frames are still available from RS but are very expensive. They can be used with wave-soldering machines.

Leon

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Amateur radio callsign: G1HSM

Erik Friesen

Do you know where I could find a picture of that machine, leon?

After this 25, I'll probably farm it out somewhere.

WBA Consulting

Leon, Good one, I completely forgot about flip frames......

ideal for you:
www.newark.com/cooper-tools-weller/weller-esf-120-antist-best-rah/weller-esf-120-antist-best/dp/15M6238

others:

www.newark.com/ideal-tek/pcsa-1/pcb-assembly-jig-esd/dp/34M7928

www.manixmfg.com/assembly.htm

www.newark.com/cliff-electronic-components/wf1/assembly-jig-pcb-aluminium/dp/08WX2622

www.bokar.com/?sub=35

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Andrew Williams
WBA Consulting
WBA-TH1M Sensirion SHT11 Module
Special Olympics Polar Bear Plunge, Mar 20, 2010
Propeller-Based Reverse Geo-Cache Birthday Present Project

Post Edited (WBA Consulting) : 2/19/2010 5:23:12 AM GMT

Erik Friesen

Thanks all, I will check into this further, the prices don't seem that bad.

Leon

This is something like the one I used to have:

uk.farnell.com/cliff-electronic-components/wfo/assembly-jig-pcb-aluminium/dp/439757

Mine was made from steel and is much more expensive now.

Leon

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Amateur radio callsign: G1HSM