STS are your “eyes and ears” in the manufacturing lines!
Here are a few examples of some non-conformities identified in our recent quality inspections conducted at various PV module manufacturing facilities, around the Globe.
Carrying out production supervision, pre-shipment inspection and other quality control activities is the most cost-effective way to avoid some of the most common performance and safety issues in the field.

– Shadows on PV Modules During EL Test
The issue was observed after a LECO (Light Electroluminescence and Camera Observation) software update that caused the laser and signal to become unsynchronized, leading to insufficient laser firing. The EL detector failed to catch all instances, allowing defective modules to pass. In response, the factory optimized CDD delay, updated the LECO software, introduced a laser defect control template, adjusted the confidence value, started daily inspections of laser parameters, and recorded all hardware adjustments.

– Scratches On PV Modules During EL Test
The scratch defects were found in PV modules, intersecting vertically with the main grid line of the 210 TopCon cells. Sampling revealed that these scratches were due to a process bottleneck with the 210 TopCon cell. The factory’s daily sampling inspections failed to detect this defect. In response, the factory tightened cell IQC sampling inspections and re-trained production line employees on customer standards.

– Bubbles from Lamination on PV Modules
The problem was caused by a damaged adhesive tape and a vacuum leak in the lamination machine, leading to bubbles. The detection system’s settings were too broad, missing smaller bubbles. Even though cleaning staff identified some defects, small and sparse bubbles were hard to detect, leading to some being missed. The factory responded by replacing the damaged tape, fixing the vacuum leak, adjusting detection system settings, conducting weekly blind tests for cleaning staff, and training employees on bubble inspection standards to improve quality control.

– Improper Spacing Between Cells
This was caused by a dirty baseplate on the soldering machine during a shift change, affecting vacuum suction and spacing. The detection system’s settings were not sensitive enough for smaller gaps near the lower limit of the standard (0.9±0.5mm). Although cleaning staff visually identified some gaps using steel rulers, these tools couldn’t measure accurately to 0.1mm, leading to some gaps being missed. To address the issue, the factory cleaned and maintained the soldering machine, trained cleaning staff to use gauge film rulers for precise gap inspection and implemented weekly blind tests to ensure thorough inspections and reduce errors.

– Glass Damaged During Transportation
The damage occurred when a forklift operator, transporting large size glass from the warehouse to the workshop, accidentally hit a support column. This accident was attributed to the operator’s inexperience with larger glass sizes and his lack of attention, compounded by missing warning marks. To address the root cause, the factory now conducts regular forklift training and assessments, prohibits untrained staff from operating forklifts, and has installed guardrails and zebra crossing markings to alert drivers to potential hazards.