Upinder,
Using IPA does not cause the residue, it simply exposes it.
Given that all fluxes leave reisdues, it follows that these MUST be benign - but how do you know, and how do you control it.
You are using flux to remove oxides and give you a good solder joint. Given that even no-cleans leave residues, it follows that these must not compromise reliability. If you are having difficulty achieving good solder joints, you turn up the fluxer, apply more flux and hey presto - you get a good joint... BUT:
Do you also have a reliable product?
Getting this under proper control may be helped by referring to ANSI-IPC-J-STD001 Appendix D.
I have more info but please ask me rather than bore everyone here on the SMTNet.
See you in Providence RI?
Regards Graham
Graham.Naisbitt@concoat.co.uk
| | All Y'll | | | | How do you clean components that must be added to an assembled board after water wash? | | | | BACKGROUND | | | | Our basic process goes like this: | | | | 1 Print paste with OA flux, place, reflow, wash | | 2 Repeat 1 | | 3 Insert PTH, OA flux, wave, wash | | 4 Insert PTH and hand solder with no-clean | | 5 Test and ship | | | | Someone has decided that for certain products the third process using no-clean produces insightly product. The solution was to scrub the boards with isopropal alcohol using "ESD paint brushes." This did a great job of making the no-clean solder joints less obvious and spreading the no-clean residue over the board surface. | | | | What do you think? | | | | Dave F | | | Dave, what kind of no-clean are u using? | | Yes, IPA will cause the residue.....try using distilled water. | | Upinder | ========== |
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