Does someone have some experience or review in the past with roller tinning machines?
I mean low cost machines with two rollers and a molten solder tank. The finished soldermasked PCB pass through the rollers (like a lamination) but instead the molten solder is impregned in the copper exposed pads of the PCB. It was (and still is in some low-end countries) a low-tech and low cost alternative to HASL. I would like to know if you have some comments about the subject, like planarity, final quality of the board, etc. I do not want to invest in a HASL facility so I would like to know if for low volumes of PCBs (1000 to 5000 pieces) those low-end roller tinning machines may have a chance, or are totally worthless in terms of quality, warping of PCB, planarity of pads, etc.