Solder Paste scrapping issues often trouble SMT process engineers. When solder paste dries and clumps, discarding it directly is the only option.

If solder paste has been opened for more than 48 hours without being used, it must be scrapped even if it appears normal. This is closely related to ambient temperature and humidity.

Foreign matter such as metal debris or dust mixed into solder paste will seriously affect soldering results. This situation must be handled decisively.

When solder paste has excessively high viscosity causing printing difficulties, it indicates that its activity has failed. At this point, performance cannot be restored through simple stirring.

Abnormal darkening of solder paste color or the appearance of odor indicates severe oxidation or contamination. Such solder paste can no longer be used in production.

If solder paste has been stored beyond the manufacturer's recommended period, it must be scrapped even if unopened. Extra caution is needed when storage conditions do not meet requirements.

If sagging or collapse occurs during solder paste use, it indicates that its thixotropy has been lost. Such solder paste cannot guarantee printing accuracy.

If opened solder paste is not stored sealed, it easily absorbs moisture and impurities when exposed to air. This situation must be handled immediately.

If solder paste is not fully stirred before use, it leads to uneven component distribution. This situation may affect soldering quality.

If solder paste has been stored in high-temperature environments for too long, active substances may be consumed prematurely. Such solder paste must be carefully evaluated before deciding whether to use it.