Maintenance of low oxygen concentration in reflow furnaces produces higher quality product, less product defect, and lower maintenance costs - potentially saving thousands of dollars per year. But only the advent of a unique non-depleting oxygen sensor by Servomex avoids problems with sensor contamination and depletion experienced by traditional sensing technologies.
THE ROLE OF OXYGEN ANALYSIS IN REFLOW FURNACES
Following the widespread elimination of chlorofluorocarbons (CFCs) due to environmental concerns, PCB manufacturers are usually required to create an inert environment in the solder furnace to reduce oxygen (O2) concentration. Historically, PCBs were cleaned with CFCbased agents, but newer solders are able to be applied in a nitrogen (N2) purged environment without any loss in quality.
The two common solder processes are wave and reflow soldering. In the wave process, the PC board is passed over a cylinder of molten solder. In the reflow process, the boards are pre-pasted with solder, and conveyed through a pre-heater to allow the solder paste to run onto the components and hold them in place.
When O2 is present in a solder furnace, it can compromise the wetting properties of the solder as it flows to the components. The result is poor solder joints: O2 compromise can be observed as grey solder joints which indicate oxidation has occurred as the solder joined the components. Monitoring the level of O2 in a furnace will ensure consistent welding quality. Also, metered N2 levels ensure optimized soldering without excessive N2 consumption.