It is true that the use of saponifiers (and other water soluble additives) will lower the surface tension and aid in under component penetration. It is also true, however, that other specific design features within a batch machine can also aid in under component penetration without the use of such chemical additives.
We have manufactured hundreds of batch machines. More than 50% of them are in use in OA flux / paste removal from fine-pitch, high-density SMT applications without the use of a chemical additive. The rest of them are cleaning no-clean and RMA, both of which require a chemical additive. I have seen some isolated cases, however, where a chemical additive is needed but these cases are quite rare.
My recommendation would be to try not to use any chemical additives if possible. The absence of chemicals provides the ability to close-loop the entire cleaning process very economically (not to mention lowering the cost of cleaning).
I would also recommend that you send samples of your boards (with plenty of flux under the components) to the equipment manufacturers to verify the acceptability of a chemical-free process.
| | Very shortly I will be evaluating OA flux and aqueous cleaning to replace our RMA and solvent cleaning process. I am primarily interested in batch aqueous cleaners for reasons of budget, floor space, etc. I am concerned about the ability of H2O to clean under low standoff components like TSOPs. Will a saponifier be necessary to help break the surface tension of the H2O (are saponifiers even compatible with OA fluxes)? I am hoping to be able to clean with just DI water. Your experiences with batch cleaners is much appreciated. | | | | Thanks, | | | | Bob | | | Some people say batch cleaners can't consistently clean fine pitch devices. Some contractors are using batch cleaners instead of in-line cleaners. But ya know Bob, you should solder some components on a board, clean it with different batch cleaners, pull the components, and measure the flux residues where the component was located. Alternately you could put some combs under the components and measure the SIR. | | My2� | | Dave F |