On Mon, 2 Jan 2012, andy pugh wrote: > Date: Mon, 2 Jan 2012 15:32:18 +0000 > From: andy pugh <bodge...@gmail.com> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: [Emc-users] Surface-Mount > > I have some surface-mount opto-sensors which have pads on the > underside, but no pins as such. > Can anyone suggest how to solder them to PCB pads? I currently have a > soldering iron, blowtorch, gas cooker and a hairdryer, though I am not > averse to buying other tools. > > -- > atp > The idea that there is no such thing as objective truth is, quite simply, > wrong.
A hair dryer is close but a little too cool. A hot air gun (the type used with heat-shrink tubing) will work. You will also want some solder paste, although it is also do-able by pre soldering the pads. With the solder paste, you apply the paste to the pads (no more than 5-10 mills thick over entire pad or equvalent blob in middle) Carefully hand place the part and heat from behind with the hot air gun. This take practice to not scorch the back of the card so a few practice runs soldering cheap parts is in order. You can see when the solder melts so just heat a little bit past this point. You can also do this without solder paste by pre-soldering the PCB pads. applying a lot of liquid flux and heating from behind. The disadvantage of this is that the bubbling flux will likely lift and displace the part so you need to build a "fence' around the part either with scrap PCB material or wire this fence needs maybe 5 -10 mills clearance around the part to allow the part to center by surface tension, and not interfere with the part pulling down to the board hen the solder melts. If you want to do more of this tha a few protos a hot-air rework station is in order, But we do BGA protos all the time this way with great success. > > ------------------------------------------------------------------------------ > Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex > infrastructure or vast IT resources to deliver seamless, secure access to > virtual desktops. With this all-in-one solution, easily deploy virtual > desktops for less than the cost of PCs and save 60% on VDI infrastructure > costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ Ridiculously easy VDI. With Citrix VDI-in-a-Box, you don't need a complex infrastructure or vast IT resources to deliver seamless, secure access to virtual desktops. With this all-in-one solution, easily deploy virtual desktops for less than the cost of PCs and save 60% on VDI infrastructure costs. Try it free! http://p.sf.net/sfu/Citrix-VDIinabox _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
