EAST PROVIDENCE, R.I., July 16, 2013 — Nordson EFD has developed the Square Wave 745NC flux dispenser for noncontact precision jetting of low-viscosity flux onto solar cell bus bars. Operating at speeds up to 500 Hz/s, the device meets the photovoltaic (PV) industry’s need to deposit continuous lines of microdots on the solder-coated metal ribbons that connect adjoining PV wafers. Flux removes oxidation and contamination to improve solar cell efficiency and power output. The device’s solenoid technology delivers a high-speed cycle rate that minimizes process variation for repeatable dot-to-dot consistency. A low actuation speed of 2 ms prevents buildup of flux crystals on the valve’s nozzle, which could prevent the fluid from being deposited precisely on the bus bar. The pistons’ unique material reduces friction and wear; tests showed more than 880 million cycles of use without deterioration. With its noncontact design, the device never touches the delicate and brittle PV wafer, minimizing breakage and rejects. A special nozzle enables multiple orifice diameters from 100 to 175 µm, so deposit sizes and volumes can be changed. The company says that the device solves the problems of slow evaporation, excess nonactivated flux, flux buildup and clogging of the nozzle, and that it prevents encapsulation delamination caused by excessive flux application.