Hi Jack I would not blame Hugo if he'd zap all of that gibberish I've send through and is hypothetically sitting in IPC archives for the generations to cherish ; but IF it's there; I did answered this one few times stating even cycles of carbon pill (on silicon membrane) switching onto flash gold pads ( 10-20umNi + 0.5umAu ) . You were told correctly not to bother with selective plating ; unless specs or standards given will force you to do so . Keep the Ni up to 20um (micrometers ; not microinches) ; and the gold optimally 0.8-1.2um to be on safe side ; however we clocked 1 Million cycles on 0.5umAu on 5.3umNi ; as I wanted to be as far from embrittlement as possible ; ITRI states 1.5umAu tops as safe limit for solder ; our internal spec states top 0.8um . We go as low as 0.3umAu ( 3.0umNi ) on some batches (yes ; very pale) without problems and switching resistivity changes . Tried the Alpha Level (silver) ; lasted only 60K's , cycled with 1/8" carbon pill ; went through to copper ; the NiAu dynamic duo is hard to beat ; logically if you see the compatible characters for this particular application . And ; in couple of decades on gold and millions of telephones behind living to tell (previous life) ; I don't think there's better, cheaper and simpler way . The only thing is if you did not solder on gold before you'll have to work harder on process than on tin ; creeps on pads much slower . So, check the classics again ; let me know if you'd get stuck . See you Jack Paul Klasek http://www.resmed.com > ---------- > From: Jack Olson[SMTP:[log in to unmask]] > Sent: Thursday, 18 March 1999 3:58 > To: [log in to unmask] > Subject: [TN] Flash Gold and Switch Contacts > > I have just read through about a thousand messages regarding gold plating > in > the Technet archive, but still couldn't find exactly what I need to know: > > We have a design with one side all contact switch patterns, and the other > side SMT components. Since we wanted to gold plate the contact patterns, > we > were told to just gold plate the whole board. > > So the question is: What gold thickness would be thin enough for the > SMT's > and still thick enough for good reliable contacts? Or is there a better > way? > > thanks in advance, > Jack > > ################################################################ > TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c > ################################################################ > To subscribe/unsubscribe, send a message to [log in to unmask] with > following text in the body: > To subscribe: SUBSCRIBE TechNet <your full name> > To unsubscribe: SIGNOFF TechNet > ################################################################ > Please visit IPC's web site (http://www.ipc.org) "On-Line Services" > section for additional information. > For technical support contact Hugo Scaramuzza at [log in to unmask] or > 847-509-9700 ext.312 > ################################################################ > ################################################################ TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c ################################################################ To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body: To subscribe: SUBSCRIBE TechNet <your full name> To unsubscribe: SIGNOFF TechNet ################################################################ Please visit IPC's web site (http://www.ipc.org) "On-Line Services" section for additional information. For technical support contact Hugo Scaramuzza at [log in to unmask] or 847-509-9700 ext.312 ################################################################