Re: [EE] Board Manufacturing by Bob Axtell .

Right, always visit the assembly house so you can understand their process. The automated placement of SMD components is a ONE-SIDE process for most assemblers. THis is because the stencil process is a one-side process, using gravity to keep the devices in place. People who have components on both sides have the second side assembled by hand. Few shops can reliably mount SMD components automatically on both sides, and ever fewer are located inside the USA. I always mount SMD on top side, then install bottom SMD manually, finally top or bottom sided thru-connectors manually, I have almost NO confidence in SMD conectors. --Bob Roland wrote: {Quote hidden}>Well, I visited an assembly house on friday for my first auto place job, and was told, if possible, to keep all componenets on one side only. I have a mix of smd on top and bottom, and leaded on top, like I see on many boards. > >But, if you keep all smd on one side, then they only need to stencil the solder paste once, and possibly also reduce the stencil cost. Also, if you keep all smd on the top, then there's no need for the glue on the underneath to stop components falling off during the reflow. > >It's best to visit the guys first before you lay the board, to see what equipment they have, and their recommendations. No need to fight with them afterwards. Also check what size pads they require for various packages. > >regards >Roland > > > > >At 06:32 PM 15/10/2005 +0200, you wrote: > > >>> What is the normal procedure for assembling boards? Do you guy just >>>put the components where you need them or you try to think how to simplify >>>assembly to lower the costs? (the components where you need them, but off >>>course always with no constraint violations). >>> >>> Well... That's about it. Any comments? >>> >>> >>> >>Hi, >> >>Yes, I always try to put SMD components on the bottom side and through hole >>components on the top side. If I have to put a component, like a LED for >>example, on the top side I choose a trough hole instead of SMD to keep assembly >>cost down - SMD on one side only. >> >>Regards / Ruben >> >> >> >>============================== >>Ruben Jönsson >>AB Liros Electronic >>Box 9124, 200 39 Malmö, Sweden >>TEL INT +46 40142078 >>FAX INT +46 40947388 >>@spam@rubenspam_OUT.....pp.sbbs.se >>============================== >> >>-