Re Graham's resonse, I have a couple of additional comments: > ---------- > From: Graham Naisbitt[SMTP:[log in to unmask]] > Sent: Friday, October 10, 1997 4:27 PM > To: [log in to unmask] > Subject: Re: [TECHNET] Assy: Water Soluble Flux > Are SIR tests required to prove cleaning methods? "Required"?? By contract: Depends on what spec you fab to. As I recall only MIL-STD-2000A (now cancelled) and ANSI/J-STD-001B specifically discuss SIR. In ANSI, it's only required for "non-traditional" fluxes (ie. fluxes not classified as "RO or RE - L0 or L1 (rosin or resin)-(<0.5% halide)". The ANSI doesn't require doing SIR for a change in cleaning (but it is strongly recommended). Required (ie. really good idea to check): We do SIR when we change flux chemistries, soldering or fluxing method, substrate (material or vendor) and cleaners. > Are SIR tests required for MIL/DOD contracts? See above, depends on contract. Typically not when just changing cleaner but in some cases when changing flux. > Can WS / OA be used on stranded wire? First off, most WS/OA fluxes are classified per ANSI/J-STD-004 as H0 or H1 (high activity/corrosivity). Per ANSI/J-STD-001B (see 4.2), type H fluxes "Type H fluxes may be used for tinning of terminals, solid wire and sealed components when performed as part of an integrated fluxing, soldering, cleaning, and cleanliness test system." Strictly speaking it's allowed but typically not recommeded (e.g. above exception allows H for SOLID wire). Problem is that these fluxes can be very corrosive and they wick up wire where they are not totally heated and not "extractable" for process control tools like Omegameter/SIR. Also, if stranded wire NEEDs OA to tin, you have bigger problems. Tossing the wire is cheaper than process controls necessary to assure no problems in OA process on stranded wire. > Which is the better process for WS / OA, Batch or In-line? Actually, depends on fluxing method, cleaning chemistry, etc. No "one answer"; we've qualified both and in some cases gotten BETTER results with batch (chemistry "a") vs. inline (chemistry "b"). Also, be aware that more power doesn't always equate to cleaner PWAs. We found REALLY high spray pressures just tend to "bounce" solvent off the substrate, leaving areas not in direct spray DIRTIER than with a lower spray pressure. ############################################################## TechNet Mail List 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 web site (http://www.ipc.org/html/forum.htm) for additional information. For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311 ##############################################################