In July last year, during a routine inspection by our South American customer, a new requirement caught us unprepared: the glass IK impact resistance test. While our 10W to 200W LED floodlights passed without issue, the 300W high-power floodlight failed dramatically-its glass shattered under impact. Crucially, the fragment pattern (see image below) convinced the customer this was not genuine tempered glass, resulting in full batch rejection.
The customer’s mandate was unequivocal: “300W glass must be fully tempered and pass IK08.”
We urgently engaged our supplier, requesting 4mm fully tempered glass samples meeting IK08. The results were disappointing – the new samples barely passed IK06, falling far short of the required protection level.
Could thicker glass solve the problem?
We escalated to 5mm thickness and produced new samples. While performance improved, it only reached IK07 – still insufficient for IK08.
These successive failures revealed a critical truth: The core determinant of IK protection isn’t thickness alone – it’s the quality of the tempering process. Substandard tempering creates uneven internal stress distribution, compromising impact resistance regardless of added thickness.
Key Lessons from a Costly Rework:
This forced full rework of our 300W floodlights became a pivotal learning opportunity:
IK Rating Decoded: The IK scale (IK00 = no protection to IK10 = maximum protection) quantifies a material’s resistance to mechanical impacts (shocks, vibrations). Higher rating = greater resilience.
Process is Paramount: True high-performance tempered glass requires precise high-temperature heating followed by rapid, uniform quenching. This creates the essential internal compressive stress layer needed to withstand IK08+ impacts.
The Outcome: Turning Failure into Foundation
Although the broader industry do not mandate strict IK ratings for such floodlights, and the client also didn’t ask for similar requirements before inspection. This incident significantly increased our glass and labor costs. Yet, the shattered glass became our most valuable teacher.
We extend sincere gratitude to our South American customer for their rigorous inspection standards. Their IK08 requirement provided a profound, practical education in glass impact resistance that transcends theoretical knowledge. This experience has fundamentally sharpened our understanding of IK ratings and reinforced that true quality lies in mastering the process, not just meeting a spec.
