At 07.22 2012.06.19, you wrote: >On Mon, Jun 18, 2012 at 9:35 AM, Electron wrote: >> Usually I make holes as tight as possibile, so that the TH components do= n't >> fall on the floor if I turn the board, but I can still insert them witho= ut >> making a war. >> >> Will this hole tolerance be still OK also for PTH, or must I make larger >> holes? High current will go through this connector and pads, so I really >> want to make sure that both sides are very well soldered. > >Not exactly an answer, but take a look at SparkFun. One of their guys >wrote up a little tutorial about staggering the pins in a multipin >header connector so that the part would hold itself in to the board. > >Josh Dear Josh, You mean this one? http://www.sparkfun.com/tutorials/114 Very interesting.. that was a good input for further Googling, that reveale= d the need for a 0.4mm bigger diameter (hole vs pin) in case of circular pins= , and 0.3mm in case of square ones (square pins measured as diagonal), to ens= ure that the solder passes through the hole and wets the other part of the PTH = board. That means pretty "big" holes, so big that the component will fall down to = the floor if the board is turned to the other side, so soldering is more diffic= ult than with tight holes, but these larger holes are necessary to let the sold= er pass through the hole (what is the English term for that?) and fill it, too= .. Optimal pad size seems as a minimum twice the diameter of the hole, three t= imes maximum (if board space allows). I would like to hear comments about these figures! I have designed and am using my own PCB software, that's why I need to figu= re these things out. Another thing that I wonder is how do other PCB software generate Gerber code for ground pours around pads (surrounding them), do th= ey use negative imaging (IIRC Gerber supports it), which is unlikely I think, = or to they "brute force" draw all the required copper around the pad and isola= tion? Cheers, Mario >--=20 >A common mistake that people make when trying to design something >completely foolproof is to underestimate the ingenuity of complete >fools. > -Douglas Adams > >--=20 >http://www.piclist.com PIC/SX FAQ & list archive >View/change your membership options at >http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .