How to Deal With Virtual Welding and Cold Welding Defects Caused by SMT Patch

Welding defects such as virtual welding and cold welding sometimes occur in electronic processing. These permissions will lead to poor welding of SMT patches. How to deal with these problems? Below, I will share how to deal with defects such as cold welding and virtual welding.

1. Reasons for cold welding

In actual electronic processing, the cold welding we often say is that the surface of the solder joint is dark, rough and not completely melted with the object to be soldered. In actual production and processing, the main reasons for the formation of cold welding of SMT chip processing are inappropriate heating temperature, deterioration of solder, long preheating time or high temperature.

Solution: Adjust the curve according to the reflow temperature curve provided by the supplier, and then adjust it according to the actual situation of the production product. Replace with new solder paste. Check whether the equipment is normal and correct the preheating conditions.

2. The Cause of False Welding

The solderability of SMT components and pads is poor, the reflow temperature or heating rate does not meet the processing requirements, the printing parameters are wrong, the residence time after printing is too long, and the activity of the solder paste is deteriorated.

Solution: strengthen the screening of PCB circuit boards and SMD components to ensure good soldering performance, adjust the reflow soldering temperature curve, change the pressure and speed of the squeegee to ensure good printing result, after the solder paste is printed, the SMD is reflowed as soon as possible.