Every batch of solder sample test materials we send to customers comes from the current month's production lot, not lab samples or leftover stock. Before solder sample testing, we must synchronously confirm the customer's stencil tension value, squeegee pressure, and printing speed; otherwise, even for the same Solder Paste, the solder joint bridging rate can differ by 12.7% under different printing parameters, and this difference is often misjudged as an equipment issue in AOI false alarms. During SMT production line testing, we will fixedly use the customer's original SPI equipment calibration parameters to horizontally compare the solder sample test data with their previous month's historical data. For example, a customer originally had a cold solder joint rate of 0.85% on 0.3mm pitch QFN devices with their previous solder paste, and after switching to Jia Jinyuan samples, the measured rate dropped to 0.23%, but the prerequisite is that they simultaneously fine-tune the reflow peak temperature from 238℃ to 242℃ and extend the soaking zone by 3 seconds. This action is not based on experience but is determined by the alloy melting plateau width in the DSC thermal analysis curve.

Wave soldering line testing places more emphasis on the dynamic wetting performance in solder sample testing. We do not only look at the static wetting angle, but pass the PCB through the furnace at a speed of 1.2 meters per minute, and continuously collect the solder joint fillet lifting length, solder penetration height, and shadow area void rate of 120 boards under the condition of chain speed fluctuation ±0.05 meters per minute. Among them, solder joints with a shadow area void rate exceeding 18% will be automatically marked and traced back to the nitrogen oxygen content in the corresponding furnace temperature zone. Because when the nitrogen purity is lower than 99.995%, even if the solder sample test uses a highly active no-clean Solder Bar, the void rate at the bottom of QFP64 pins will sharply increase to 31.4%. This value cannot be read at all on the customer's original production line nitrogen detector, and must be reverse-verified through solder sample testing.

The yield numbers in all solder sample test reports are bound to specific equipment models and firmware versions. For example, a customer using a KE2070 placement machine with V12.3 firmware had a 0.17% tombstoning rate when placing 0402 components, and after switching to Jia Jinyuan samples, the tombstoning rate dropped to 0.03%, but if they do not simultaneously adjust the nozzle vacuum value from -65kPa to -72kPa, this improvement will not occur at all. Free sample sending for solder sample testing is not a formality; it is to let customers use their own production lines, their own personnel, and their own process parameters to run real order boards. We only bring data collectors and portable XRF composition analyzers to stay on-site at the factory. All raw data is uploaded to an encrypted cloud drive in real time, and customers can access the furnace temperature curve screenshots and AOI defect coordinates of any test board at any time.