SOLDERING

An issue often found during printing is that printing the first panel after a pause in production yields unstable results

Depending on the operation environment, if a printer is paused for an extended period of time during production a lower volume of solder is transferred, leading to poor quality printing that results in defective products. The most common reason is that the flux present in the apertures of the screen mask dries out. Flux acts as a lubricant against the mask when solder is being filled or during snap-off. But this lubricating effect does not happen when the flux becomes dried, causing poor solder filling and poor solder release.

Fuji has designed a printing mode geared toward maintaining quality

On Fuji printers, if the paused period exceeds a set time the print conditions are adjusted at the printer to ensure print quality when printing resumes and the timing to lower the table is adjusted automatically to match the progress at later stages in the line. This prevents flux from drying before the panel can be moved into the next stage of production and allows for stable print quality without losing productivity. Test data (graph 1) shows that the solder transfer volume is not reduced even after the machine was paused for a period of 60 minutes.