After we switched to JJY JY-901 high-oxidation-resistance Solder Bars on the wave soldering line, we found that under the same conditions of 320°C solder pot temperature and nitrogen protection flow maintained at 8L/min, the amount of solder dross scooped per shift dropped from the original average of 2.1kg to around 0.9kg. This change was not achieved by forcibly increasing nitrogen pressure, but because the rare earth composite antioxidant contained in the solder bar itself continuously forms a dynamic self-healing oxidation barrier layer in the molten state, reducing the oxidation rate of the solder surface by more than 63%, thereby greatly cutting the physical basis for tin oxide and unmelted metal particles to aggregate into dross.

The formation of solder dross is never determined by a single factor. It is closely related to the length of time the solder is exposed to air, and is also directly affected by the original oxygen content of the solder bar, the distribution uniformity of impurity elements, and the viscosity change gradient near the melting point. The ex-factory oxygen content of JJY JY-901 solder bars is controlled within 80ppm, and the fluctuation range of easily segregated elements such as lead, bismuth, and zinc is less than ±0.005%. This ensures that during repeated melting and cooling processes, local component segregation will not induce accelerated micro-area oxidation, thereby preventing the continuous accumulation and amplification of fine solder dross particles.

We compared the dross morphology differences between ordinary solder bars and JJY JY-901 used alternately on the same equipment. The solder dross produced by ordinary solder bars is mostly loose and flocculent, mixed with a large amount of black oxides and easily broken, while the solder dross formed by JY-901 is significantly denser, grayish-white and bright, with regular edges. This indicates that its oxidation reaction is effectively delayed, and the proportion of recoverable tin metal remaining in the dross is increased by about 35%, which directly reduces the solder material loss cost during each pot cleaning.

It is worth noting that high-oxidation-resistance solder bars cannot completely replace daily process control. For example, if the rail inclination deviates from the standard value by more than 0.5°, or the chain speed fluctuation exceeds the set value by ±3%, it will still cause Flux carbide residue on the bottom of the PCB to mix into the solder, forming composite solder dross together with trace tin oxide. Therefore, the upgrade of solder bars and the calibration of equipment status must be carried out simultaneously; otherwise, the effect of changing only the material will be largely offset by mechanical deviations.

On-site tracking data shows that without changing other parameters, after using JJY JY-901, the number of manual dross scooping operations per week in the solder pot dropped from 4.3 to 1.7, the stable duration of the solder surface level was extended by 5.2 hours, and the rework rate caused by solder joint spikes and bridging in AOI inspection decreased by 0.18 percentage points. All these changes come from the cascading improvements brought by the reduced generation of solder dross, rather than being achieved by increasing temperature or extending soldering time.

A colleague once tried to simulate the effect of high-oxidation-resistance solder bars by adding antioxidant powder, but found that the powder dispersed unevenly in the solder, and excessively high local concentration instead aggravated dross agglomeration. Moreover, it cannot establish a continuous antioxidant barrier in the early stage of solder bar melting like JY-901. Therefore, the metallurgical consistency of the material itself is more reliable than post-hoc remediation, especially in large-volume continuous production, where this difference becomes more and more obvious as the running time increases.