Wave Soldering Flus Selection

Dear Greg H

On this link there is some usefull information about the choise of flux for wavesoldering.

http://www.epa.gov/docs/ozone/title6/snap/icel/noclean2.pdf

Anders

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In response No that�s not all you need to think about, but lets look at each and then talk of others.

a)The condition of the solderable surface on boards (and components) degrades over time or can be supplied in poor condition (to thin or thick HASL,Cleanliness etc..) all of which effect solderability. If you have good suppliers and turn material rather quickly you may be able to get away with a less aggressive flux. If you are a contact manufacture and have very little control you will want to use the most aggressive flux you can (and your customers allow).

b)The more aggressive (higher solid content) the flux the more corrosive it will be and vise versa. If you have a good cleaning process you can get away with using an aggressive flux but you better be monitoring it.

c)Again the higher the solid content the more conductive it will be.

d)The easier it is to remove the cleaner the boards will be with less effort which means less $$$. for example noclean is very easy to remove as you can leave it on!! no extra cost. RMA's can be Di washed, this adds cost equimpment,manpower maintenance, time.

e)Soldering temps may very between flux types some need a longer soak than others to burn off the alcohol or water. you would care about this if your products could not withstand the necessary time or temp. Or if your equipment couldn�t heat your product to the necessary temp within the needed times.

Of on to more variables.

1) Are you performing ICT if so be careful with the selection of any nocleans fluxes. Some are probable and others are not. If selecting a material that will be washed off don�t worry. 2) Can your current equipment support the flux. Spray or foam, some fluxes especially nocleans are easier to spray than foam. Can the preheaters heat high and long enough to burn off all of the alch/water prior to Pot. Washing if using a material that needs to be washed can the equipment clean it to your specified levels. 3) If this is not your own product what do your customers require or allow? 4) Does the material fit your process, If the boards being processed are mixed technology what type of flux is being used it your SMT process. If using noclean at SMT I dont think you would want to use a water sol at Wave.

Rather long I know but I hope it helps.

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ICT probe problems, appearance of res on the boards, and unexpected interactions in RF applications.

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