Reasons and solutions for cold soldering and false soldering in reflow soldering

During the reflow soldering process, there may sometimes be some problems that affect product quality, and cold soldering false soldering is one of the more common adverse phenomena. JEENOCE will introduce the reasons and solutions for reflow soldering and false soldering.

1、 Reasons and Treatment of Reflow Welding and Cold Welding

1: Reason for occurrence: In reflow soldering, what we commonly refer to as cold soldering is that the surface of the solder joint is generally dark, rough, and does not completely melt with the object being soldered. The main reasons for the formation of cold welding in reflow soldering are improper heating temperature, expired solder, prolonged preheating time, or high temperature.

2: Solution: Based on the reflux temperature curve provided by the supplier, adjust the curve, and then adjust it according to the actual situation of the production product, replace it with new solder paste, check whether the equipment can function properly, and correct the preheating conditions.

2、 Reasons and treatment of false soldering in reflow soldering

1: Reasons for formation: The solderability of reflow soldering components and pads is relatively poor, the reflow soldering temperature or heating speed does not meet production and processing standards, there are errors in printing technical parameters, the dwell time after printing is too long, and the activity of solder paste decreases.

2: Solution: Improve the selection of PCB circuit boards and SMT components to ensure good soldering performance; Adjust the reflow soldering temperature curve; Modify the scraper pressure and speed for SMT processing to ensure a good printing effect for SMT processing; After solder paste printing, mount and reflow solder as early as possible.