I disagree about the maintenance issues with tin/copper solder. All high tin content solders are hard on machines (silver or not). More dross? Controlling the back flow, front flow velocity and AVOID constant surface cleaning will reduce your dross production (lead or lead-free). Also, only use the chip (turbulant) wave when required. I have noticed a tendency for some to use it for every assembly. This, regardless, if it is warranted or not.
Also, not all machine designs are created equal. Example: I have two diferent machines that run identical alloys and flux. One produces 5X more dross than the other. Both are setup as per the manufacturers instructions.
Oh yeah, if your running a 24 inch machine and 90% of your assemblies are 10 inches wide, yeah your gonna produce piles of dross.
I keep hearing this BS about how sac alloys for wave "improve wetting". Its the flux that will principly affect wetting.
As far as N2...its the same arguement we had in the early 90's. Nitrogen is a great fix all for a defective or marginal process....except it isn't free.
The bottom line here is materials and process evaluation!
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