Yes it all depends on the assmebly house. For us, we have in-house SMD pick and place machines and reflow soldering and wave soldering machines. But we do not have automatic placement machine for PTH components since manual insertion is still cheaper. It is good to have less process on the SMD reflow if possible. For us, two side reflow is esitmated to be 10% more expensive than single side reflow. It is good to have all the SMD components on the same side as the PTH components if wave soldering is involved. If the SMD components are on the opposite side of the PTH components (thus on the same side as the leads of the through-hole components), then an extra glue process are required since it needs to withstand the wave soldering. The SMD pads which need to be glued and go through wave soldering process will generally be bigger than the reflow pads so it will take more space. Therefore if the PTH components count are not high, we normally use two side reflow and use manual soldering for the PTH components. SMD connectors can be difficult to deal with so we normally have mechanical design features to protect them from being lift up. Regards, Xiaofan On 10/16/05, Bob Axtell wrote: > 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 > -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist